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Du X, Zhang P, Zhang G, Gao H, Zhang L, Zhang M, Wang T, Gong J. Confinement of ionomer for electrocatalytic CO 2 reduction reaction via efficient mass transfer pathways. Natl Sci Rev 2024; 11:nwad149. [PMID: 38213529 PMCID: PMC10776366 DOI: 10.1093/nsr/nwad149] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 05/21/2023] [Indexed: 01/13/2024] Open
Abstract
Gas diffusion electrodes (GDEs) mediate the transport of reactants, products and electrons for the electrocatalytic CO2 reduction reaction (CO2RR) in membrane electrode assemblies. The random distribution of ionomer, added by the traditional physical mixing method, in the catalyst layer of GDEs affects the transport of ions and CO2. Such a phenomenon results in elevated cell voltage and decaying selectivity at high current densities. This paper describes a pre-confinement method to construct GDEs with homogeneously distributed ionomer, which enhances mass transfer locally at the active centers. The optimized GDE exhibited comparatively low cell voltages and high CO Faradaic efficiencies (FE > 90%) at a wide range of current densities. It can also operate stably for over 220 h with the cell voltage staying almost unchanged. This good performance can be preserved even with diluted CO2 feeds, which is essential for pursuing a high single-pass conversion rate. This study provides a new approach to building efficient mass transfer pathways for ions and reactants in GDEs to promote the electrocatalytic CO2RR for practical applications.
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Affiliation(s)
- Xiaowei Du
- School of Chemical Engineering and Technology, Key Laboratory for Green Chemical Technology of the Ministry of Education, Tianjin University, Tianjin300072, China
- CollaborativeInnovation Center of Chemical Science and Engineering (Tianjin), Tianjin300072, China
| | - Peng Zhang
- School of Chemical Engineering and Technology, Key Laboratory for Green Chemical Technology of the Ministry of Education, Tianjin University, Tianjin300072, China
- CollaborativeInnovation Center of Chemical Science and Engineering (Tianjin), Tianjin300072, China
- National Industry-Education Platform of Energy Storage, Tianjin University, Tianjin300350, China
| | - Gong Zhang
- School of Chemical Engineering and Technology, Key Laboratory for Green Chemical Technology of the Ministry of Education, Tianjin University, Tianjin300072, China
- CollaborativeInnovation Center of Chemical Science and Engineering (Tianjin), Tianjin300072, China
| | - Hui Gao
- School of Chemical Engineering and Technology, Key Laboratory for Green Chemical Technology of the Ministry of Education, Tianjin University, Tianjin300072, China
- CollaborativeInnovation Center of Chemical Science and Engineering (Tianjin), Tianjin300072, China
| | - Lili Zhang
- School of Chemical Engineering and Technology, Key Laboratory for Green Chemical Technology of the Ministry of Education, Tianjin University, Tianjin300072, China
- CollaborativeInnovation Center of Chemical Science and Engineering (Tianjin), Tianjin300072, China
| | - Mengmeng Zhang
- School of Chemical Engineering and Technology, Key Laboratory for Green Chemical Technology of the Ministry of Education, Tianjin University, Tianjin300072, China
- CollaborativeInnovation Center of Chemical Science and Engineering (Tianjin), Tianjin300072, China
| | - Tuo Wang
- School of Chemical Engineering and Technology, Key Laboratory for Green Chemical Technology of the Ministry of Education, Tianjin University, Tianjin300072, China
- CollaborativeInnovation Center of Chemical Science and Engineering (Tianjin), Tianjin300072, China
- National Industry-Education Platform of Energy Storage, Tianjin University, Tianjin300350, China
- Joint School of the National University of Singapore and Tianjin University, International Campus of Tianjin University, Fuzhou350207, China
| | - Jinlong Gong
- School of Chemical Engineering and Technology, Key Laboratory for Green Chemical Technology of the Ministry of Education, Tianjin University, Tianjin300072, China
- CollaborativeInnovation Center of Chemical Science and Engineering (Tianjin), Tianjin300072, China
- Haihe Laboratory of Sustainable Chemical Transformations, Tianjin300192, China
- National Industry-Education Platform of Energy Storage, Tianjin University, Tianjin300350, China
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Xu Y, Zhang L, Chen W, Cui H, Cai J, Chen Y, Feliu JM, Herrero E. Boosting Oxygen Reduction at Pt(111)|Proton Exchange Ionomer Interfaces through Tuning the Microenvironment Water Activity. ACS Appl Mater Interfaces 2024; 16:4540-4549. [PMID: 38227931 DOI: 10.1021/acsami.3c14208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
A proton exchange ionomer is one of the most important components in membrane electrode assemblies (MEAs) of polymer electrolyte membrane fuel cells (PEMFCs). It acts as both a proton conductor and a binder for nanocatalysts and carbon supports. The structure and the wetting conditions of the MEAs have a great impact on the microenvironment at the three-phase interphases in the MEAs, which can significantly influence the electrode kinetics such as the oxygen reduction reaction (ORR) at the cathode. Herein, by using the Pt(111)|X ionomer interface as a model system (X = Nafion, Aciplex, D72), we find that higher drying temperature lowers the onset potential for sulfonate adsorption and reduces apparent ORR current, while the current wave for OHad formation drops and shifts positively. Surprisingly, the intrinsic ORR activity is higher after properly correcting the blocking effect of Pt active sites by sulfonate adsorption and the poly(tetrafluoroethylene) (PTFE) skeleton. These results are well explained by the reduced water activity at the interfaces induced by the ionomer/PTFE, according to the mixed potential effect. Implications for how to prepare MEAs with improved ORR activity are provided.
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Affiliation(s)
- Yujun Xu
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Lulu Zhang
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Wei Chen
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Haowen Cui
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Jun Cai
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yanxia Chen
- Hefei National Research Center for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Juan M Feliu
- Instituto de Electroquímica, Universidad de Alicante, Apdo. 99, Alicante E-03080, Spain
| | - Enrique Herrero
- Instituto de Electroquímica, Universidad de Alicante, Apdo. 99, Alicante E-03080, Spain
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Ube T. Three-dimensional nanostructure analysis of non-stained Nafion in fuel cell electrode by combined ADF-STEM tomography. Microscopy (Oxf) 2024:dfae002. [PMID: 38226523 DOI: 10.1093/jmicro/dfae002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/23/2023] [Accepted: 01/11/2024] [Indexed: 01/17/2024] Open
Abstract
The polymer electrolyte fuel cell (PEFC) is one of the strongest candidates for a next-generation power source for vehicles which do not emit carbon dioxide gas (CO2) as exhaust gas. The key factor in PEFCs is the nano-scaled electrochemical reactions that take place on the catalyst material and an ionomer supported by a carbon support. However, because the nano-scaled morphological features of the key materials in the catalyst compound cannot be observed clearly by transmission electron microscopy, improvement of PEFC performance had been approached by an imaginal schematic diagram based on an electrochemical analysis. In this study, we revealed the nano-scaled morphological features of the PEFC electrode in three dimensions and performed a quantitative analysis of the nanostructure by the newly-developed "Combined ADF-STEM tomography technique." This method combines information from plural ADF detectors with different electron collection angles and can emphasize the difference of the electron scattering intensity between the ionomer and carbon in the cross-sectional image of the reconstructed three-dimensional data. Therefore, this segmentation method utilizing image contrast does not require a high electron beam current like that used in EDX analysis, and thus is suitable for electron beam damage-sensitive materials. By eliminating the process of manually determining the thresholds for obtaining classified component data from grayscale data, the obtained 3D structures have sufficient accuracy to allow quantitative analysis and specify the nano-scaled structural parameters directly related to power generation characteristics.
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Affiliation(s)
- Takuji Ube
- Nano-scale Characterization Center, JFE Techno-Research Corporation, Tokyo, Japan
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Corona-García C, Onchi A, Santiago AA, Soto TE, Vásquez-García SR, Pacheco-Catalán DE, Vargas J. Synthesis, Characterization, and Proton Conductivity of Muconic Acid-Based Polyamides Bearing Sulfonated Moieties. Polymers (Basel) 2023; 15:4499. [PMID: 38231907 PMCID: PMC10707785 DOI: 10.3390/polym15234499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/13/2023] [Accepted: 11/16/2023] [Indexed: 01/19/2024] Open
Abstract
Most commercially available polymers are synthesized from compounds derived from petroleum, a finite resource. Because of this, there is a growing interest in the synthesis of new polymeric materials using renewable monomers. Following this concept, this work reports on the use of muconic acid as a renewable source for the development of new polyamides that can be used as proton-exchange membranes. Muconic acid was used as a comonomer in polycondensation reactions with 4,4'-(hexafluoroisopropylidene)bis(p-phenyleneoxy)dianiline, 2,5-diaminobencensulfonic acid, and 4,4'-diamino-2,2'-stilbenedisulfonic acid as comonomers in the synthesis of two new series of partially renewable aromatic-aliphatic polyamides, in which the degree of sulfonation was varied. Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H, 13C, and 19F-NMR) techniques were used to confirm the chemical structures of the new polyamides. It was also observed that the degree of sulfonation was proportional to the molar ratio of the diamines in the feed. Subsequently, membranes were prepared by casting, and a complete characterization was conducted to determine their decomposition temperature (Td), glass transition temperature (Tg), density (ρ), and other physical properties. In addition, water uptake (Wu), ion-exchange capacity (IEC), and proton conductivity (σp) were determined for these membranes. Electrochemical impedance spectroscopy (EIS) was used to determine the conductivity of the membranes. MUFASA34 exhibited a σp value equal to 9.89 mS·cm-1, being the highest conductivity of all the membranes synthesized in this study.
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Affiliation(s)
- Carlos Corona-García
- Instituto de Investigaciones en Materiales, Unidad Morelia, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex Hacienda de San José de la Huerta, Morelia C.P. 58190, Michoacán, Mexico; (C.C.-G.); (A.O.)
| | - Alejandro Onchi
- Instituto de Investigaciones en Materiales, Unidad Morelia, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex Hacienda de San José de la Huerta, Morelia C.P. 58190, Michoacán, Mexico; (C.C.-G.); (A.O.)
| | - Arlette A. Santiago
- Escuela Nacional de Estudios Superiores, Unidad Morelia, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex Hacienda de San José de la Huerta, Morelia C.P. 58190, Michoacán, Mexico;
| | - Tania E. Soto
- Centro de Investigaciones Químicas, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Cuernavaca C.P. 62209, Morelos, Mexico;
| | - Salomón Ramiro Vásquez-García
- Facultad de Ingeniería Química, Universidad Michoacana de San Nicolás de Hidalgo, General Francisco J. Múgica s/n, Morelia C.P. 58060, Michoacán, Mexico;
| | - Daniella Esperanza Pacheco-Catalán
- Unidad de Energía Renovable, Centro de Investigación Científica de Yucatán, A.C. Carretera Sierra Papacal-Chuburná Puerto Km 5, Sierra Papacal, Mérida C.P. 97302, Yucatán, Mexico;
| | - Joel Vargas
- Instituto de Investigaciones en Materiales, Unidad Morelia, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex Hacienda de San José de la Huerta, Morelia C.P. 58190, Michoacán, Mexico; (C.C.-G.); (A.O.)
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García-Salaberri PA. A Numerical Assessment of Mitigation Strategies to Reduce Local Oxygen and Proton Transport Resistances in Polymer Electrolyte Fuel Cells. Materials (Basel) 2023; 16:6935. [PMID: 37959530 PMCID: PMC10647390 DOI: 10.3390/ma16216935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 11/15/2023]
Abstract
The optimized design of the catalyst layer (CL) plays a vital role in improving the performance of polymer electrolyte membrane fuel cells (PEMFCs). The need to improve transport and catalyst activity is especially important at low Pt loading, where local oxygen and ionic transport resistances decrease the performance due to an inevitable reduction in active catalyst sites. In this work, local oxygen and ionic transport are analyzed using direct numerical simulation on virtually reconstructed microstructures. Four morphologies are examined: (i) heterogeneous, (ii) uniform, (iii) uniform vertically-aligned, and (iv) meso-porous ionomer distributions. The results show that the local oxygen transport resistance can be significantly reduced, while maintaining good ionic conductivity, through the design of high porosity CLs (ε≃ 0.6-0.7) with low agglomerated ionomer morphologies. Ionomer coalescence into thick films can be effectively mitigated by increasing the uniformity of thin films and reducing the tortuosity of ionomer distribution (e.g., good ionomer interconnection in supports with a vertical arrangement). The local oxygen resistance can be further decreased by the use of blended ionomers with enhanced oxygen permeability and meso-porous ionomers with oxygen transport routes in both water and ionomer. In summary, achieving high performance at low Pt loading in next-generation CLs must be accomplished through a combination of high porosity, uniform and low tortuosity ionomer distribution, and oxygen transport through activated water.
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Affiliation(s)
- Pablo A García-Salaberri
- Department of Thermal and Fluids Engineering, University Carlos III of Madrid, 28911 Leganés, Spain
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Harada M, Kadoura H, Takata SI, Iwase H, Kajiya S, Suzuki T, Hasegawa N, Shinohara A, Kato S. Equation Elucidating the Catalyst-Layer Proton Conductivity in a Polymer Electrolyte Fuel Cell Based on the Ionomer Distribution Determined Using Small-Angle Neutron Scattering. ACS Appl Mater Interfaces 2023; 15:42594-42602. [PMID: 37650483 DOI: 10.1021/acsami.3c08432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
The performance of a polymer electrolyte fuel cell can be enhanced by improving the proton conductivity of the catalyst layer, where the oxygen reduction reaction generates electrochemical power. Protons are conducted through the ionomer coatings on catalyst-supporting carbon particles, which form porous structures that facilitate oxygen diffusion during the reaction within the catalyst layer. Therefore, while a higher ionomer content in the catalyst layer is favorable, the proton conductivity is additionally governed by the type of carbon support. As the influence of the ionomer distribution is not fully understood, we introduce a novel proton conductivity model for use in simulating catalyst layers with various amounts of ionomers and different carbon types. This proton conductivity model considers that several ionomers occur as thin films with drastically suppressed proton conductivities. Although evaluating the thin-film ionomer fraction is challenging, proton-conducting ion clusters in thick-film ionomers have been detected by characterizing the catalyst layers via small-angle neutron scattering. Our model reveals that reducing the fraction of the thin-film ionomer or avoiding factors that suppress its proton conduction improves the performance of the catalyst layer.
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Affiliation(s)
- Masashi Harada
- Toyota Central R&D Laboratories, Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan
| | - Hiroaki Kadoura
- Toyota Central R&D Laboratories, Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan
| | - Shin-Ichi Takata
- J-PARC Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - Hiroki Iwase
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), Tokai, Ibaraki 319-1106, Japan
| | - Shuji Kajiya
- Toyota Central R&D Laboratories, Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan
| | - Takahisa Suzuki
- Toyota Central R&D Laboratories, Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan
| | - Naoki Hasegawa
- Toyota Central R&D Laboratories, Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan
| | - Akihiro Shinohara
- Toyota Central R&D Laboratories, Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan
| | - Satoru Kato
- Toyota Central R&D Laboratories, Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan
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Dony P, Berzin F. Thermogravimetric, Morphological and Infrared Analysis of Blends Involving Thermoplastic Starch and Poly(ethylene-co-methacrylic acid) and Its Ionomer Form. Molecules 2023; 28:molecules28114519. [PMID: 37298994 DOI: 10.3390/molecules28114519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/26/2023] [Accepted: 05/27/2023] [Indexed: 06/12/2023] Open
Abstract
This study focuses on the thermal properties and structural features of blends consisting of thermoplastic starch (TPS) and poly(ethylene-co-methacrylic acid) copolymer (EMAA) or its ionomer form (EMAA-54Na). The aim is to investigate how carboxylate functional groups of the ionomer form intervene in blends compatibility at the interface of the two materials and how this impacts their properties. Two series of blends (TPS/EMAA and TPS/EMAA-54Na) were produced with an internal mixer, with TPS compositions between 5 and 90 wt%. Thermogravimetry shows two main weight losses, indicating that TPS and the two copolymers are primarily immiscible. However, a small weight loss existing at intermediate degradation temperature between those of the two pristine components reveals specific interactions at the interface. At a mesoscale level, scanning electron microscopy confirmed thermogravimetry results and showed a two-phase domain morphology, with a phase inversion at around 80 wt% TPS, but also revealed a different surface appearance evolution between the two series. Fourier-transformed infrared spectroscopy analysis also revealed discrepancies in fingerprint between the two series of blends, analysed in terms of additional interactions in TPS/EMAA-54Na coming from the supplementary sodium neutralized carboxylate functions of the ionomer.
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Affiliation(s)
- Philippe Dony
- Institue de Thermique, Mécanique et Matériaux (ITheMM), Université de Reims Champagne Ardenne, EA 7548, CEDEX 2, 51687 Reims, France
| | - Françoise Berzin
- Fractionnement des AgroRessources et Environnement (FARE), Université de Reims Champagne Ardenne, INRAE, UMR 0614, 51100 Reims, France
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Grandi M, Gatalo M, Kamšek AR, Kapun G, Mayer K, Ruiz-Zepeda F, Šala M, Marius B, Bele M, Hodnik N, Bodner M, Gaberšček M, Hacker V. Mechanistic Study of Fast Performance Decay of PtCu Alloy-based Catalyst Layers for Polymer Electrolyte Fuel Cells through Electrochemical Impedance Spectroscopy. Materials (Basel) 2023; 16:ma16093544. [PMID: 37176426 PMCID: PMC10180127 DOI: 10.3390/ma16093544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/06/2023] [Accepted: 04/17/2023] [Indexed: 05/15/2023]
Abstract
In the past, platinum-copper catalysts have proven to be highly active for the oxygen reduction reaction (ORR), but transferring the high activities measured in thin-film rotating disk electrodes (TF-RDEs) to high-performing membrane electrode assemblies (MEAs) has proven difficult due to stability issues during operation. High initial performance can be achieved. However, fast performance decay on a timescale of 24 h is induced by repeated voltage load steps with H2/air supplied. This performance decay is accelerated if high relative humidity (>60% RH) is set for a prolonged time and low voltages are applied during polarization. The reasons and possible solutions for this issue have been investigated by means of electrochemical impedance spectroscopy and distribution of relaxation time analysis (EIS-DRT). The affected electrochemical sub-processes have been identified by comparing the PtCu electrocatalyst with commercial Pt/C benchmark materials in homemade catalyst-coated membranes (CCMs). The proton transport resistance (Rpt) increased by a factor of ~2 compared to the benchmark materials. These results provide important insight into the challenges encountered with the de-alloyed PtCu/KB electrocatalyst during cell break-in and operation. This provides a basis for improvements in the catalysts' design and break-in procedures for the highly attractive PtCu/KB catalyst system.
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Affiliation(s)
- Maximilian Grandi
- Institute of Chemical Engineering and Environmental Technology, Graz University of Technology, Inffeldgasse 25/C, 8010 Graz, Austria
| | - Matija Gatalo
- Department of Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Ana Rebeka Kamšek
- Department of Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Gregor Kapun
- Department of Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Kurt Mayer
- Institute of Chemical Engineering and Environmental Technology, Graz University of Technology, Inffeldgasse 25/C, 8010 Graz, Austria
| | - Francisco Ruiz-Zepeda
- Department of Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Martin Šala
- Department of Analytical Chemistry, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Bernhard Marius
- Institute of Chemical Engineering and Environmental Technology, Graz University of Technology, Inffeldgasse 25/C, 8010 Graz, Austria
| | - Marjan Bele
- Department of Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Nejc Hodnik
- Department of Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Merit Bodner
- Institute of Chemical Engineering and Environmental Technology, Graz University of Technology, Inffeldgasse 25/C, 8010 Graz, Austria
| | - Miran Gaberšček
- Department of Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Viktor Hacker
- Institute of Chemical Engineering and Environmental Technology, Graz University of Technology, Inffeldgasse 25/C, 8010 Graz, Austria
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Yuan D, Li X, Yao H, Li Y, Zhu X, Zhao J, Zhang H, Zhang Y, Jie ETJ, Cai Y, Srinivasan M. A Liquid Crystal Ionomer-Type Electrolyte toward Ordering-Induced Regulation for Highly Reversible Zinc Ion Battery. Adv Sci (Weinh) 2023; 10:e2206469. [PMID: 36646504 PMCID: PMC10015864 DOI: 10.1002/advs.202206469] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Indexed: 06/17/2023]
Abstract
Novel electrolyte is being pursued toward exploring Zn chemistry in zinc ion batteries. Here, a fluorine-free liquid crystal (LC) ionomer-type zinc electrolyte is presented, achieving simultaneous regulated water activity and long-range ordering of conduction channels and SEI. Distinct from water network or local ordering in current advances, long-range ordering of layered water channels is realized. Via manipulating water activity, conductivities range from ≈0.34 to 15 mS cm-1 , and electrochemical window can be tuned from ≈2.3-4.3 V. The Zn|Zn symmetric cell with LC gel exhibits highly reversible Zn stripping/plating at 5 mA cm-2 and 5 mAh cm-2 for 800 h, with retained ordering of water channels. The capability of gel for inducing in situ formation of long-range ordered layer SEI associated with alkylbenzene sulfonate anion is uncovered. V2 O5 /Zn cell with the gel shows much improved cycling stability comparing to conventional zinc electrolytes, where the preserved structure of V2 O5 is associated with the efficiently stabilized Zn anode by the gel. Via long-range ordering-induced regulation on ion transport, electrochemical stability, and interfacial reaction, the development of LC electrolyte provides a pathway toward advancing aqueous rechargeable batteries.
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Affiliation(s)
- Du Yuan
- College of Materials Science and EngineeringChangsha University of Science and TechnologyChangshaHunan410004P. R. China
| | - Xin Li
- College of Materials Science and EngineeringChangsha University of Science and TechnologyChangshaHunan410004P. R. China
| | - Hong Yao
- College of Materials Science and EngineeringChangsha University of Science and TechnologyChangshaHunan410004P. R. China
| | - Yuhang Li
- College of Materials Science and EngineeringChangsha University of Science and TechnologyChangshaHunan410004P. R. China
| | - Xiaobo Zhu
- College of Materials Science and EngineeringChangsha University of Science and TechnologyChangshaHunan410004P. R. China
| | - Jin Zhao
- State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM)Nanjing University of Posts & Telecommunications9 Wenyuan RoadNanjing210023China
| | - Haitao Zhang
- Institute of Process EngineeringChinese Academy of SciencesBeijing100190China
| | - Yizhou Zhang
- School of Chemistry and Materials ScienceInstitute of Advanced Materials and Flexible Electronics (IAMFE)Nanjing University of Information Science and TechnologyNanjing210044China
| | - Ernest Tang Jun Jie
- School of Materials Science and EngineeringNanyang Technological UniversityBlock N4.150 Nanyang AvenueSingapore639798Singapore
| | - Yi Cai
- School of Materials Science and EngineeringNanyang Technological UniversityBlock N4.150 Nanyang AvenueSingapore639798Singapore
| | - Madhavi Srinivasan
- School of Materials Science and EngineeringNanyang Technological UniversityBlock N4.150 Nanyang AvenueSingapore639798Singapore
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Wang Q, Li Y, Xiao J, Xia L. Intelligent Eucommia ulmoides Rubber/ Ionomer Blends with Thermally Activated Shape Memory and Self-Healing Properties. Polymers (Basel) 2023; 15. [PMID: 36904423 DOI: 10.3390/polym15051182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/16/2023] [Accepted: 02/23/2023] [Indexed: 03/02/2023] Open
Abstract
Intelligent Eucommia ulmoides rubber (EUR) and ionomer Surlyn resin (SR) blends were prepared and studied in this manuscript. This is the first paper to combine EUR with SR to prepare blends with both the shape memory effect and self-healing capability. The mechanical, curing, thermal, shape memory and self-healing properties were studied by a universal testing machine, differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA), respectively. Experimental results showed that the increase in ionomer content not only improved mechanical and shape memory properties but also endowed the compounds with excellent self-healing ability under the appropriate environmental conditions. Notably, the self-healing efficiency of the composites reached 87.41%, which is much higher than the efficiency of other covalent cross-linking composites. Therefore, these novel shape memory and self-healing blends can expand the use of natural Eucommia ulmoides rubber, such as in special medical devices, sensors and actuators.
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Sharma R, Morgen P, Chiriaev S, Lund PB, Larsen MJ, Sieborg B, Grahl-Madsen L, Andersen SM. Insights into Degradation of the Membrane-Electrode Assembly Performance in Low-Temperature PEMFC: the Catalyst, the Ionomer, or the Interface? ACS Appl Mater Interfaces 2022; 14:49658-49671. [PMID: 36315079 DOI: 10.1021/acsami.2c12327] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Here, we report a study on the structural characteristics of membrane electrode assembly (MEA) samples obtained from a low-temperature (LT) polymer electrolyte membrane (PEM) fuel cell (FC) stack subjected to long-term durability testing for ∼18,500 h of nominal operation along with ∼900 on/off cycles accumulated over the operation time, with the total power production being 3.39 kW h/cm2 of MEA and the overall degradation being 87% based on performance loss. The chemical and physical states of the degraded MEAs were investigated through structural characterizations aiming to probe their different components, namely the cathode and anode electrocatalysts, the Nafion ionomer in the catalyst layers (CLs), the gas diffusion layers (GDLs), and the PEM. Surprisingly, X-ray diffraction and electron microscopy studies suggested no significant degradation of the electrocatalysts. Similarly, the cathode and anode GDLs exhibited no significant change in porosity and structure as indicated by BET analysis and helium ion microscopy. Nevertheless, X-ray fluorescence spectroscopy, elemental analysis through a CHNS analyzer, and comprehensive investigations by X-ray photoelectron spectroscopy suggested significant degradation of the Nafion, especially in terms of sulfur content, that is, the abundance of the -SO3- groups responsible for H+ conduction. Hence, the degradation of the Nafion, in both of the CLs and in the PEM, was found to be the principal mechanism for performance degradation, while the Pt/C catalyst degradation in terms of particle size enlargement or mass loss was minimal. The study suggests that under real-life operating conditions, ionomer degradation plays a more significant role than electrocatalyst degradation in LT-PEMFCs, in contrast to many scientific studies under artificial stress conditions. Mitigation of the ionomer degradation must be emphasized as a strategy to improve the PEMFC's durability.
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Affiliation(s)
- Raghunandan Sharma
- Department of Green Technology, University of Southern Denmark, Campusvej 55, 5230Odense, Denmark
| | - Per Morgen
- Department of Green Technology, University of Southern Denmark, Campusvej 55, 5230Odense, Denmark
| | - Serguei Chiriaev
- NANOSYD, The Mads Clausen Institute, University of Southern Denmark, Alison 2, 6400Sønderborg, Denmark
| | - Peter Brilner Lund
- Department of Green Technology, University of Southern Denmark, Campusvej 55, 5230Odense, Denmark
- IRD Fuel Cells A/S, Emil Neckelmanns Vej 15, 5220Odense, Denmark
| | | | - Bertil Sieborg
- IRD Fuel Cells A/S, Emil Neckelmanns Vej 15, 5220Odense, Denmark
| | | | - Shuang Ma Andersen
- Department of Green Technology, University of Southern Denmark, Campusvej 55, 5230Odense, Denmark
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12
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Nallayagari AR, Sgreccia E, Pasquini L, Sette M, Knauth P, Di Vona ML. Impact of Anion Exchange Ionomers on the Electrocatalytic Performance for the Oxygen Reduction Reaction of B-N Co-doped Carbon Quantum Dots on Activated Carbon. ACS Appl Mater Interfaces 2022; 14:46537-46547. [PMID: 36194150 DOI: 10.1021/acsami.2c11802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Composite electrocatalytic electrodes made from B-N co-doped carbon quantum dots (CQD) and various anion exchange ionomers (AEI) are studied for the oxygen reduction reaction (ORR) in alkaline solutions. The quantity and positions of dopants in CQD, prepared by hydrothermal synthesis, are analyzed by various spectroscopies, including 11B NMR spectroscopy that evidenced boronic acid at edge sites. The AEI are synthesized with various backbones, including more hydrophilic polysulfone, hydrophobic poly(alkylene biphenyl), and poly(2,6-dimethyl-1,4-phenylene oxide) with intermediate hydrophilicity; the functional groups are trimethylammonium moieties grafted on long (LC) or short (SC) side chains. The CQD/AEI ink is drop-casted on activated carbon paper, and the samples are fixed on a rotating disk electrode and studied in three-electrode configuration in oxygen-saturated 0.1 M KOH. The onset potentials are among the best in the literature (Eonset ≈ 0.94 V vs RHE). The highest electrocatalytic activity is observed for electrodes containing AEI with long side chains; the sample containing PPO LC attains excellent ORR currents approaching that of benchmark Pt/C cloth. The electrocatalytic performances are discussed in view of the many relevant AEI parameters, including hydrophilicity, oxygen permeability, catalyst dispersivity, and ionic conductivity.
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Affiliation(s)
- Ashwini Reddy Nallayagari
- Dep. Industrial Engineering and International Laboratory: Ionomer Materials for Energy, University of Rome Tor Vergata, 00133Roma, Italy
- MADIREL (UMR 7246) and International Laboratory: Ionomer Materials for Energy, Aix Marseille Univ, CNRS, Campus St Jérôme, 13013Marseille, France
| | - Emanuela Sgreccia
- Dep. Industrial Engineering and International Laboratory: Ionomer Materials for Energy, University of Rome Tor Vergata, 00133Roma, Italy
| | - Luca Pasquini
- MADIREL (UMR 7246) and International Laboratory: Ionomer Materials for Energy, Aix Marseille Univ, CNRS, Campus St Jérôme, 13013Marseille, France
| | - Marco Sette
- Dep. Chemical Sciences and Technologies, University of Rome Tor Vergata, via della Ricerca Scientifica, 00133Roma, Italy
| | - Philippe Knauth
- MADIREL (UMR 7246) and International Laboratory: Ionomer Materials for Energy, Aix Marseille Univ, CNRS, Campus St Jérôme, 13013Marseille, France
| | - Maria Luisa Di Vona
- Dep. Industrial Engineering and International Laboratory: Ionomer Materials for Energy, University of Rome Tor Vergata, 00133Roma, Italy
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13
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Chatterjee S, Zamani E, Farzin S, Evazzade I, Obewhere OA, Johnson TJ, Alexandrov V, Dishari SK. Molecular-Level Control over Ionic Conduction and Ionic Current Direction by Designing Macrocycle-Based Ionomers. JACS Au 2022; 2:1144-1159. [PMID: 35647599 PMCID: PMC9131371 DOI: 10.1021/jacsau.2c00143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/22/2022] [Accepted: 04/28/2022] [Indexed: 06/15/2023]
Abstract
Poor ionic conductivity of the catalyst-binding, sub-micrometer-thick ionomer layers in energy conversion and storage devices is a huge challenge. However, ionomers are rarely designed keeping in mind the specific issues associated with nanoconfinement. Here, we designed nature-inspired ionomers (calix-2) having hollow, macrocyclic, calix[4]arene-based repeat units with precise, sub-nanometer diameter. In ≤100 nm-thick films, the in-plane proton conductivity of calix-2 was up to 8 times higher than the current benchmark ionomer Nafion at 85% relative humidity (RH), while it was 1-2 orders of magnitude higher than Nafion at 20-25% RH. Confocal laser scanning microscopy and other synthetic techniques allowed us to demonstrate the role of macrocyclic cavities in boosting the proton conductivity. The systematic self-assembly of calix-2 chains into ellipsoids in thin films was evidenced from atomic force microscopy and grazing incidence small-angle X-ray scattering measurements. Moreover, the likelihood of alignment and stacking of macrocyclic units, the presence of one-dimensional water wires across this macrocycle stacks, and thus the formation of long-range proton conduction pathways were suggested by atomistic simulations. We not only did see an unprecedented improvement in thin-film proton conductivity but also saw an improvement in proton conductivity of bulk membranes when calix-2 was added to the Nafion matrices. Nafion-calix-2 composite membranes also took advantage of the asymmetric charge distribution across calix[4]arene repeat units collectively and exhibited voltage-gating behavior. The inclusion of molecular macrocyclic cavities into the ionomer chemical structure can thus emerge as a promising design concept for highly efficient ion-conducting and ion-permselective materials for sustainable energy applications.
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14
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Krivina RA, Lindquist GA, Yang MC, Cook AK, Hendon CH, Motz AR, Capuano C, Ayers KE, Hutchison JE, Boettcher SW. Three-Electrode Study of Electrochemical Ionomer Degradation Relevant to Anion-Exchange-Membrane Water Electrolyzers. ACS Appl Mater Interfaces 2022; 14:18261-18274. [PMID: 35435656 DOI: 10.1021/acsami.1c22472] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Among existing water electrolysis (WE) technologies, anion-exchange-membrane water electrolyzers (AEMWEs) show promise for low-cost operation enabled by the basic solid-polymer electrolyte used to conduct hydroxide ions. The basic environment within the electrolyzer, in principle, allows the use of non-platinum-group metal catalysts and less-expensive cell components compared to acidic-membrane systems. Nevertheless, AEMWEs are still underdeveloped, and the degradation and failure modes are not well understood. To improve performance and durability, supporting electrolytes such as KOH and K2CO3 are often added to the water feed. The effect of the anion interactions with the ionomer membrane (particularly other than OH-), however, remains poorly understood. We studied three commercial anion-exchange ionomers (Aemion, Sustainion, and PiperION) during oxygen evolution (OER) at oxidizing potentials in several supporting electrolytes and characterized their chemical stability with surface-sensitive techniques. We analyzed factors including the ionomer conductivity, redox potential, and pH tolerance to determine what governs ionomer stability during OER. Specifically, we discovered that the oxidation of Aemion at the electrode surface is favored in the presence of CO32-/HCO3- anions perhaps due to the poor conductivity of that ionomer in the carbonate/bicarbonate form. Sustainion tends to lose its charge-carrying groups as a result of electrochemical degradation favored in basic electrolytes. PiperION seems to be similarly negatively affected by a pH drop and low carbonate/bicarbonate conductivity under the applied oxidizing potential. The insight into the interactions of the supporting electrolyte anions with the ionomer/membrane helps shed light on some of the degradation pathways possible inside of the AEMWE and enables the informed design of materials for water electrolysis.
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Affiliation(s)
- Raina A Krivina
- Department of Chemistry and Biochemistry and Materials Science Institute, University of Oregon, Eugene, Oregon 97403, United States
- Oregon Center for Electrochemistry, University of Oregon, Eugene, Oregon 97403, United States
| | - Grace A Lindquist
- Department of Chemistry and Biochemistry and Materials Science Institute, University of Oregon, Eugene, Oregon 97403, United States
- Oregon Center for Electrochemistry, University of Oregon, Eugene, Oregon 97403, United States
| | - Min Chieh Yang
- Department of Chemistry and Biochemistry and Materials Science Institute, University of Oregon, Eugene, Oregon 97403, United States
- Oregon Center for Electrochemistry, University of Oregon, Eugene, Oregon 97403, United States
| | - Amanda K Cook
- Department of Chemistry and Biochemistry and Materials Science Institute, University of Oregon, Eugene, Oregon 97403, United States
| | - Christopher H Hendon
- Department of Chemistry and Biochemistry and Materials Science Institute, University of Oregon, Eugene, Oregon 97403, United States
- Oregon Center for Electrochemistry, University of Oregon, Eugene, Oregon 97403, United States
| | - Andrew R Motz
- Nel Hydrogen, Wallingford, Connecticut 06492, United States
| | | | | | - James E Hutchison
- Department of Chemistry and Biochemistry and Materials Science Institute, University of Oregon, Eugene, Oregon 97403, United States
| | - Shannon W Boettcher
- Department of Chemistry and Biochemistry and Materials Science Institute, University of Oregon, Eugene, Oregon 97403, United States
- Oregon Center for Electrochemistry, University of Oregon, Eugene, Oregon 97403, United States
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15
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Jin WS, Sahu P, Park SM, Jeon JH, Kim NI, Lee JH, Oh JS. Design of Self-Healing EPDM/ Ionomer Thermoplastic Vulcanizates by Ionic Cross-Links for Automotive Application. Polymers (Basel) 2022; 14:polym14061156. [PMID: 35335487 PMCID: PMC8953676 DOI: 10.3390/polym14061156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/09/2022] [Accepted: 03/10/2022] [Indexed: 11/16/2022] Open
Abstract
The development of smart elastomeric materials with inherent self-repairing abilities after mechanical damage has important technological and scientific implications, particularly in regard to the durability and life cycle of rubber products. The interest in self-healing materials for automotive applications is rapidly growing along with the increasing importance of vehicle scratch quality and quantity. The creation of a reversible network by noncovalent ionic cross-linking in elastomer/rubber blends is an effective approach to generate the self-healing phenomenon, with reprocessing and recycling properties. In this work, thermoplastic vulcanizates (TPVs) were prepared using ethylene-propylene-diene (EPDM) polymers and high-acid-containing thermoplastic ionomers. Along with the general EPDM, maleic anhydride grafted EPDM (EPDM-g-MAH) was also used for the preparation of the TPVs. The strategy was based on a simple ionic crosslinking reaction between the carboxyl groups present in the ionomer and zinc oxide (ZnO), where the formation of reversible Zn2+ salt bondings exhibits the self-healing behavior. The heterogeneous blending of EPDM and ionomers was also used to investigate the thermal and mechanical properties of the TPVs. The experimental findings were further supported by the surface morphology of the fracture surfaces viewed using microscopy. The self-healing behavior of the TPVs has been identified by scratch resistance testing, where the EPDM-g-MAH TPVs showed excellent healing efficiency of the scratch surface. Therefore, this work provides an efficient approach to fabricate new ionically cross-linked thermoplastic vulcanizates with excellent mechanical and self-repairing properties for the skins of automotive interior door trims and instrument panel applications.
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Affiliation(s)
- Woo Seok Jin
- Department of Materials Engineering and Convergence Technology, ReCAPT, Gyeongsang National University, 501, Jinju-daero, Jinju 52828, Korea; (W.S.J.); (P.S.)
| | - Pranabesh Sahu
- Department of Materials Engineering and Convergence Technology, ReCAPT, Gyeongsang National University, 501, Jinju-daero, Jinju 52828, Korea; (W.S.J.); (P.S.)
| | - Sung Min Park
- With Advanced Passion & System, WAPS Co., Ltd., 8F, 45, Centum dong-ro, Haeundae-gu, Busan 48059, Korea;
| | - Jun Ha Jeon
- Industrial Materials Research Center, Korea Institute of Footwear & Leather Technology, 152, Danggamseo-ro, Busanjin-gu, Busan 47154, Korea;
| | - Nam Il Kim
- Energy Materials R&D Center, Korea Automotive Technology Institute, Cheonan 31214, Korea; (N.I.K.); (J.H.L.)
| | - Jae Hyeon Lee
- Energy Materials R&D Center, Korea Automotive Technology Institute, Cheonan 31214, Korea; (N.I.K.); (J.H.L.)
| | - Jeong Seok Oh
- Department of Materials Engineering and Convergence Technology, ReCAPT, Gyeongsang National University, 501, Jinju-daero, Jinju 52828, Korea; (W.S.J.); (P.S.)
- Correspondence: ; Tel.: +82-055-772-1658
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16
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Zhao N, Shi Z, Girard F. Superior Proton Exchange Membrane Fuel Cell (PEMFC) Performance Using Short-Side-Chain Perfluorosulfonic Acid (PFSA) Membrane and Ionomer. Materials (Basel) 2021; 15:ma15010078. [PMID: 35009232 PMCID: PMC8745893 DOI: 10.3390/ma15010078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/13/2021] [Accepted: 12/17/2021] [Indexed: 06/07/2023]
Abstract
Optimization of the ionomer materials in catalyst layers (CLs) which sometimes is overlooked has been equally crucial as selection of the membranes in membrane electrode assembly (MEA) for achieving a superior performance in proton exchange membrane fuel cells (PEMFCs). Four combinations of the MEAs composed of short-side-chain (SSC) and long-side-chain (LSC) perfluorosulfonic acid (PFSA) polymers as membrane and ionomer materials have been prepared and tested under various temperatures and humidity conditions, aiming to investigate the effects of different side chain polymer in membranes and CLs on fuel cell performance. It is discovered that SSC PFSA polymer used as membrane and ionomer in CL yields better fuel cell performance than LSC PFSA polymer, especially at high temperature and low RH conditions. The MEA with the SSC PFSA employed both as a membrane and as an ionomer in cathode CL demonstrates the best cell performance amongst the investigated MEAs. Furthermore, various electrochemical diagnoses have been applied to fundamentally understand the contributions of the different resistances to the overall cell performance. It is illustrated that the charge transfer resistance (Rct) made the greatest contribution to the overall cell resistance and then membrane resistance (Rm), implying that the use of the advanced ionomer in CL could lead to more noticeable improvement in cell performance than only the substitution as the membrane.
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17
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Truszkowska A, Porfiri M. Molecular dynamics of ionic polymer-metal composites. Philos Trans A Math Phys Eng Sci 2021; 379:20200408. [PMID: 34455834 DOI: 10.1098/rsta.2020.0408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/10/2021] [Indexed: 06/13/2023]
Abstract
Ionic polymer-metal composites (IPMCs) constitute a promising class of soft, active materials with potentially ubiquitous use in science and engineering. Realizing the full potential of IPMCs calls for a deeper understanding of the mechanisms underpinning their most intriguing characteristics: the ability to deform under an electric field and the generation of a voltage upon mechanical deformation. These behaviours are tightly linked to physical phenomena at the level of atoms, including rearrangements of ions and molecules, along with the formation of sub-nanometre thick double layers on the surface of the metal electrodes. Several continuum theories have been developed to describe these phenomena, but their experimental and theoretical validation remains incomplete. IPMC modelling at the atomistic scale could beget valuable support for these efforts, by affording granular analysis of individual atoms. Here, we present a simplified atomistic model of IPMCs based on classical molecular dynamics. The three-dimensional IPMC membrane is constrained by two smooth walls, a simplified analogue of metal electrodes, impermeable only to counterions. The electric field is applied as an additional force acting on all the atoms. We demonstrate the feasibility of simulating counterions' migration and pile-up upon the application of an electric field, similar to experimental observations. By analysing the spatial configuration of atoms and stress distribution, we identify two mechanisms for stress generation. The presented model offers new insight into the physical underpinnings of actuation and sensing in IPMCs. This article is part of the theme issue 'Progress in mesoscale methods for fluid dynamics simulation'.
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Affiliation(s)
- A Truszkowska
- Department of Mechanical and Aerospace Engineering, New York University, Brooklyn, NY, USA
| | - M Porfiri
- Department of Mechanical and Aerospace Engineering, New York University, Brooklyn, NY, USA
- Department of Biomedical Engineering, New York University, Tandon School of Engineering, Brooklyn, NY, USA
- Center for Urban Science and Progress, New York University, Tandon School of Engineering, Brooklyn, NY, USA
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18
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Scalet JM, Suekama TC, Jeong J, Gehrke SH. Enhanced Mechanical Properties by Ionomeric Complexation in Interpenetrating Network Hydrogels of Hydrolyzed Poly (N-vinyl Formamide) and Polyacrylamide. Gels 2021; 7:80. [PMID: 34209543 PMCID: PMC8293209 DOI: 10.3390/gels7030080] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/18/2021] [Accepted: 06/20/2021] [Indexed: 02/02/2023] Open
Abstract
Tough hydrogels were made by hydrolysis of a neutral interpenetrating network (IPN) of poly (N-vinyl formamide) PNVF and polyacrylamide (PAAm) networks to form an IPN of polyvinylamine (PVAm) and poly (acrylic acid) (PAAc) capable of intermolecular ionic complexation. Single network (SN) PAAm and SN PNVF have similar chemical structures, parameters and physical properties. The hypothesis was that starting with neutral IPN networks of isomeric monomers that hydrolyze to comparable extents under similar conditions would lead to formation of networks with minimal phase separation and maximize potential for charge-charge interactions of the networks. Sequential IPNs of both PNVF/PAAm and PAAm/PNVF were synthesized and were optically transparent, an indication of homogeneity at submicron length scales. Both IPNs were hydrolyzed in base to form PVAm/PAAc and PAAc/PVAm IPNs. These underwent ~5-fold or greater decrease in swelling at intermediate pH values (3-6), consistent with the hypothesis of intermolecular charge complexation, and as hypothesized, the globally neutral, charge-complexed gel states showed substantial increases in failure properties upon compression, including an order of magnitude increases in toughness when compared to their unhydrolyzed states or the swollen states at high or low pH values. There was no loss of mechanical performance upon repeated compression over 95% strain.
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Affiliation(s)
| | | | | | - Stevin H. Gehrke
- Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, KS 66045, USA; (J.M.S.); (T.C.S.); (J.J.)
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19
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Koga M, Matsumoto H, Kunishima M, Tokita M, Masunaga H, Ohta N, Takeuchi A, Mizukado J, Sugimori H, Shinohara K, Uemura S, Yoshida T, Hirai S. Microstructure Investigation of Polymer Electrolyte Fuel Cell Catalyst Layers Containing Perfluorosulfonated Ionomer. Membranes (Basel) 2021; 11:466. [PMID: 34202780 DOI: 10.3390/membranes11070466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/16/2021] [Accepted: 06/22/2021] [Indexed: 11/17/2022]
Abstract
Perfluorosulfonated ionomers are the most successful ion-exchange membranes at an industrial scale. One recent, cutting-edge application of perfluorosulfonated ionomers is in polymer electrolyte fuel cells (PEFCs). In PEFCs, the ionomers are used as a component of the catalyst layer (CL) in addition to functioning as a proton-exchange membrane. In this study, the microstructures in the CLs of PEFCs were characterized by combined synchrotron X-ray scattering and transmission electron microscopy (TEM) analyses. The CL comprised a catalyst, a support, and an ionomer. Fractal dimensional analysis of the combined ultrasmall- and small-angle X-ray scattering profiles indicated that the carbon-black-supported Pt catalyst (Pt/CB) surface was covered with the ionomer in the CL. Anomalous X-ray scattering revealed that the Pt catalyst nanoparticles on the carbon surfaces were aggregated in the CLs. These findings are consistent with the ionomer/catalyst microstructures and ionomer coverage on the Pt/CB surface obtained from TEM observations.
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20
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Guo Y, Yang D, Li B, Yang D, Ming P, Zhang C. Effect of Dispersion Solvents and Ionomers on the Rheology of Catalyst Inks and Catalyst Layer Structure for Proton Exchange Membrane Fuel Cells. ACS Appl Mater Interfaces 2021; 13:27119-27128. [PMID: 34086430 DOI: 10.1021/acsami.1c07070] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
This study investigated the effects of the dielectric constant (ε) of a dispersion solvent and ionomer content on the rheology of graphitized carbon (GC)-supported Pt catalyst ink and the structure of catalyst layers (CLs). The ionomer dispersions and catalyst inks were tested using rheological techniques, zeta (ξ) potential, and dynamic light scattering measurements. Results showed that increases in the solvent ε or ionomer content increased the ξ-potential of catalyst particles in the ink, which reduced the catalyst agglomerate size. Steady-state and oscillation scans showed that the Pt/GC catalyst ink had shear-thinning properties and gel-like behavior. The ink with a solvent ε of 40 tended to be more Newtonian fluid, with low yield stress (σy). The ionomer content altered the rheology of the ink by changing the internal interaction of inks. Solvents with ε of 70 and 55 enhanced the adsorption of ionomers onto catalysts, thereby increasing the adhesion between ink particles and reducing the risk of CL cracking. As the ionomer content increased, the catalyst absorbed more ionomers in inks, increasing the fracture toughness of CLs, which reduced the crack width.
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Affiliation(s)
- Yuqing Guo
- School of Automotive Studies, Tongji University, Jiading Campus, 4800 Cao'an Road, Shanghai 201804, China
- Clean Energy Automotive Engineering Center, Tongji University, Jiading Campus, 4800 Cao'an Road, Shanghai 201804, China
| | - Daozeng Yang
- School of Automotive Studies, Tongji University, Jiading Campus, 4800 Cao'an Road, Shanghai 201804, China
- Clean Energy Automotive Engineering Center, Tongji University, Jiading Campus, 4800 Cao'an Road, Shanghai 201804, China
| | - Bing Li
- School of Automotive Studies, Tongji University, Jiading Campus, 4800 Cao'an Road, Shanghai 201804, China
- Clean Energy Automotive Engineering Center, Tongji University, Jiading Campus, 4800 Cao'an Road, Shanghai 201804, China
| | - Daijun Yang
- School of Automotive Studies, Tongji University, Jiading Campus, 4800 Cao'an Road, Shanghai 201804, China
- Clean Energy Automotive Engineering Center, Tongji University, Jiading Campus, 4800 Cao'an Road, Shanghai 201804, China
| | - Pingwen Ming
- School of Automotive Studies, Tongji University, Jiading Campus, 4800 Cao'an Road, Shanghai 201804, China
- Clean Energy Automotive Engineering Center, Tongji University, Jiading Campus, 4800 Cao'an Road, Shanghai 201804, China
| | - Cunman Zhang
- School of Automotive Studies, Tongji University, Jiading Campus, 4800 Cao'an Road, Shanghai 201804, China
- Clean Energy Automotive Engineering Center, Tongji University, Jiading Campus, 4800 Cao'an Road, Shanghai 201804, China
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21
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Deng G, Schoch TD, Cavicchi KA. Systematic Modification of the Glass Transition Temperature of Ion-Pair Comonomer Based Polyelectrolytes and Ionomers by Copolymerization with a Chemically Similar Cationic Monomer. Gels 2021; 7:45. [PMID: 33924350 PMCID: PMC8167584 DOI: 10.3390/gels7020045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/02/2021] [Accepted: 04/04/2021] [Indexed: 11/20/2022] Open
Abstract
Ion-pair comonomers (IPCs) where both the anion and cation contain polymerizable functional groups offer a route to prepare polyampholyte, ion-containing polymers. Polymerizing vinyl functional groups by free-radical polymerization produces bridging ion-pairs that act as non-covalent crosslinks between backbone segments. In particular the homopolymerization of the IPC vinyl benzyl tri-n-octylphosphonium styrene sulfonate produces a stiff, glassy polymer with a glass transition temperature (Tg) of 191 °C, while copolymerization with a non-ionic acrylate produces microphase separates ionomers with ion-rich and ion-poor domains. This work investigates the tuning of the Tg of the polyelectrolyte or ion-rich domains of the ionomers by copolymerizing with vinyl benzyl tri-n-octylphosphonium p-toluene sulfonic acid. This chemically similar repeat unit with pendant rather than bridging ion-pairs lowers the Tg compared to the polyelectrolyte or ionomer containing only the IPC segments. Rheological measurements were used to characterize the thermomechanical behavior and Tg of different copolymers. The Tg variation in the polyelectrolyte vs. weight fraction IPC could be fit with either the Gordon-Taylor or Couchman-Karasz equation. Copolymerization of IPC with a chemically similar cationic monomer offers a viable route to systematically vary the Tg of the resulting polymers useful for tailoring the material properties in applications such as elastomers or shape memory polymers.
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Affiliation(s)
- Guodong Deng
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH 44325, USA; (G.D.); (T.D.S.)
- Promerus LLC., 225 W Bartges St, Akron, OH 44307, USA
| | - Timothy D. Schoch
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH 44325, USA; (G.D.); (T.D.S.)
- Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, USA
| | - Kevin A. Cavicchi
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH 44325, USA; (G.D.); (T.D.S.)
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Kumeda T, Hoshi N, Nakamura M. Effect of Hydrophobic Cations on the Inhibitors for the Oxygen Reduction Reaction on Anions and Ionomers Adsorbed on Single-Crystal Pt Electrodes. ACS Appl Mater Interfaces 2021; 13:15866-15871. [PMID: 33755425 DOI: 10.1021/acsami.1c01421] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Weakening of the poisoning by the specifically adsorbed anions assists in developing next-generation electrocatalysts for use in low-temperature fuel cells. In this study, we evaluated how hydrophobic cations with different alkyl chain lengths affect the oxygen reduction reaction (ORR) activities on the single-crystal Pt surfaces in contact with sulfuric acid solution and Nafion ionomers. Interfacial tetraalkylammonium cations with longer alkyl chains activated the ORR on the Pt(111) surface. In a solution containing tetrahexylammonium cations (THA+), the ORR activities on Pt(111) in sulfuric acid solution and on Nafion-modified Pt(111) in perchloric acid solution were four and eight times higher than those in the solutions without THA+, respectively. Infrared spectroscopy revealed the reduction of the amount of (bi)sulfate anions and the sulfonate group of Nafion adsorbed on Pt(111) due to the presence of THA+. The hydrophobic cations weaken the noncovalent interactions between specifically adsorbed species and promote the ORR.
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Affiliation(s)
- Tomoaki Kumeda
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan
| | - Nagahiro Hoshi
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan
| | - Masashi Nakamura
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan
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23
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Pasquini L, Zhakisheva B, Sgreccia E, Narducci R, Di Vona ML, Knauth P. Stability of Proton Exchange Membranes in Phosphate Buffer for Enzymatic Fuel Cell Application: Hydration, Conductivity and Mechanical Properties. Polymers (Basel) 2021; 13:polym13030475. [PMID: 33540921 PMCID: PMC7867367 DOI: 10.3390/polym13030475] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 11/16/2022] Open
Abstract
Proton-conducting ionomers are widespread materials for application in electrochemical energy storage devices. However, their properties depend strongly on operating conditions. In bio-fuel cells with a separator membrane, the swelling behavior as well as the conductivity need to be optimized with regard to the use of buffer solutions for the stability of the enzyme catalyst. This work presents a study of the hydrolytic stability, conductivity and mechanical behavior of different proton exchange membranes based on sulfonated poly(ether ether ketone) (SPEEK) and sulfonated poly(phenyl sulfone) (SPPSU) ionomers in phosphate buffer solution. The results show that the membrane stability can be adapted by changing the casting solvent (DMSO, water or ethanol) and procedures, including a crosslinking heat treatment, or by blending the two ionomers. A comparison with NafionTM shows the different behavior of this ionomer versus SPEEK membranes.
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Affiliation(s)
- Luca Pasquini
- CNRS, MADIREL (UMR 7246) and International Laboratory: Ionomer Materials for Energy, Aix Marseille Univ, Campus St. Jérôme, 13013 Marseille, France; (B.Z.); (P.K.)
- Correspondence:
| | - Botagoz Zhakisheva
- CNRS, MADIREL (UMR 7246) and International Laboratory: Ionomer Materials for Energy, Aix Marseille Univ, Campus St. Jérôme, 13013 Marseille, France; (B.Z.); (P.K.)
| | - Emanuela Sgreccia
- Department Industrial Engineering and International Laboratory: Ionomer Materials for Energy, University of Rome Tor Vergata, 00133 Roma, Italy; (E.S.); (R.N.); (M.L.D.V.)
| | - Riccardo Narducci
- Department Industrial Engineering and International Laboratory: Ionomer Materials for Energy, University of Rome Tor Vergata, 00133 Roma, Italy; (E.S.); (R.N.); (M.L.D.V.)
| | - Maria Luisa Di Vona
- Department Industrial Engineering and International Laboratory: Ionomer Materials for Energy, University of Rome Tor Vergata, 00133 Roma, Italy; (E.S.); (R.N.); (M.L.D.V.)
| | - Philippe Knauth
- CNRS, MADIREL (UMR 7246) and International Laboratory: Ionomer Materials for Energy, Aix Marseille Univ, Campus St. Jérôme, 13013 Marseille, France; (B.Z.); (P.K.)
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Lo Vecchio C, Carbone A, Trocino S, Gatto I, Patti A, Baglio V, Aricò AS. Anionic Exchange Membrane for Photo-Electrolysis Application. Polymers (Basel) 2020; 12:E2991. [PMID: 33333931 DOI: 10.3390/polym12122991] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/11/2020] [Accepted: 12/12/2020] [Indexed: 11/17/2022] Open
Abstract
Tandem photo-electro-chemical cells composed of an assembly of a solid electrolyte membrane and two low-cost photoelectrodes have been developed to generate green solar fuel from water-splitting. In this regard, an anion-exchange polymer-electrolyte membrane, able to separate H2 evolved at the photocathode from O2 at the photoanode, was investigated in terms of ionic conductivity, corrosion mitigation, and light transmission for a tandem photo-electro-chemical configuration. The designed anionic membranes, based on polysulfone polymer, contained positive fixed functionalities on the side chains of the polymeric network, particularly quaternary ammonium species counterbalanced by hydroxide anions. The membrane was first investigated in alkaline solution, KOH or NaOH at different concentrations, to optimize the ion-exchange process. Exchange in 1M KOH solution provided high conversion of the groups, a high ion-exchange capacity (IEC) value of 1.59 meq/g and a hydroxide conductivity of 25 mS/cm at 60 °C for anionic membrane. Another important characteristic, verified for hydroxide membrane, was its transparency above 600 nm, thus making it a good candidate for tandem cell applications in which the illuminated photoanode absorbs the highest-energy photons (< 600 nm), and photocathode absorbs the lowest-energy photons. Furthermore, hydrogen crossover tests showed a permeation of H2 through the membrane of less than 0.1%. Finally, low-cost tandem photo-electro-chemical cells, formed by titanium-doped hematite and ionomer at the photoanode and cupric oxide and ionomer at the photocathode, separated by a solid membrane in OH form, were assembled to optimize the influence of ionomer-loading dispersion. Maximum enthalpy (1.7%), throughput (2.9%), and Gibbs energy efficiencies (1.3%) were reached by using n-propanol/ethanol (1:1 wt.) as solvent for ionomer dispersion and with a 25 µL cm-2 ionomer loading for both the photoanode and the photocathode.
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25
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Abdullayeva N, Kumtepe A, Altaf CT, Seckin H, Sankir ND, Sankir M. Dual- Ionomer-Based Device: Acetylcholine Transport and Nonenzymatic Sensing. ACS Appl Mater Interfaces 2020; 12:50039-50051. [PMID: 33084309 DOI: 10.1021/acsami.0c13725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The malfunctioning in the release of acetylcholine (ACh+), leading to consequential damages in the neural system, has become an impulsion for the development of numerous progressive transport and detection gadgets. However, several challenges, such as laterality and complexity of transport devices, low precision of amperometric detection systems, and sumptuous, multistaged enzymatic quantification methods, have not yet been overcome. Herein, ionomers, because of their selective ion transporting nature, are chosen as suitable candidates for being implemented into both targeted ACh+ delivery and sensing systems. Based on these two approaches, for the very first time in the literature, the disulfonated poly(arylene ether sulfone) membrane is concurrently (i) used in the mimicry of transduction of the electrical-to-ionic signal in a neural network as "Acetylcholine Pen" (ACh+ Pen) and (ii) operated as a highly sensitive, conductivity-based ACh+ quantifier. Our dual device, being able to operate under an actual action potential of 55 mVbias, shows a strong potential of future applicability in real-time ionic delivery-and-sensing systems.
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Affiliation(s)
- Nazrin Abdullayeva
- Micro and Nanotechnology Graduate Program, TOBB University of Economics and Technology, Sogutozu Caddesi No. 43, Sogutozu, 06560 Ankara, Turkey
| | - Alihan Kumtepe
- Micro and Nanotechnology Graduate Program, TOBB University of Economics and Technology, Sogutozu Caddesi No. 43, Sogutozu, 06560 Ankara, Turkey
| | - Cigdem Tuc Altaf
- Micro and Nanotechnology Graduate Program, TOBB University of Economics and Technology, Sogutozu Caddesi No. 43, Sogutozu, 06560 Ankara, Turkey
| | - Hakan Seckin
- Neurosurgery Clinic, Medicana Bursa Hospital, Izmir Yolu No. 41, Odunluk Nilufer, 16110 Bursa, Turkey
| | - Nurdan Demirci Sankir
- Micro and Nanotechnology Graduate Program, TOBB University of Economics and Technology, Sogutozu Caddesi No. 43, Sogutozu, 06560 Ankara, Turkey
- Department of Materials Science and Nanotechnology Engineering, TOBB University of Economics and Technology, Sogutozu Caddesi No. 43, Sogutozu, 06560 Ankara, Turkey
| | - Mehmet Sankir
- Micro and Nanotechnology Graduate Program, TOBB University of Economics and Technology, Sogutozu Caddesi No. 43, Sogutozu, 06560 Ankara, Turkey
- Department of Materials Science and Nanotechnology Engineering, TOBB University of Economics and Technology, Sogutozu Caddesi No. 43, Sogutozu, 06560 Ankara, Turkey
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Dickinson EJF, Smith G. Modelling the Proton-Conductive Membrane in Practical Polymer Electrolyte Membrane Fuel Cell (PEMFC) Simulation: A Review. Membranes (Basel) 2020; 10:E310. [PMID: 33126688 PMCID: PMC7692588 DOI: 10.3390/membranes10110310] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/21/2020] [Accepted: 10/22/2020] [Indexed: 11/23/2022]
Abstract
Theoretical models used to describe the proton-conductive membrane in polymer electrolyte membrane fuel cells (PEMFCs) are reviewed, within the specific context of practical, physicochemical simulations of PEMFC device-scale performance and macroscopically observable behaviour. Reported models and their parameterisation (especially for Nafion 1100 materials) are compiled into a single source with consistent notation. Detailed attention is given to the Springer-Zawodzinski-Gottesfeld, Weber-Newman, and "binary friction model" methods of coupling proton transport with water uptake and diffusive water transport; alongside, data are compiled for the corresponding parameterisation of proton conductivity, water sorption isotherm, water diffusion coefficient, and electroosmotic drag coefficient. Subsequent sections address the formulation and parameterisation of models incorporating interfacial transport resistances, hydraulic transport of water, swelling and mechanical properties, transient and non-isothermal phenomena, and transport of dilute gases and other contaminants. Lastly, a section is dedicated to the formulation of models predicting the rate of membrane degradation and its influence on PEMFC behaviour.
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27
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Mardle P, Thirunavukkarasu G, Guan S, Chiu YL, Du S. Comparative Study of PtNi Nanowire Array Electrodes toward Oxygen Reduction Reaction by Half-Cell Measurement and PEMFC Test. ACS Appl Mater Interfaces 2020; 12:42832-42841. [PMID: 32865384 DOI: 10.1021/acsami.0c11531] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A clear understanding of catalytic activity enhancement mechanisms in fuel cell operation is necessary for a full degree translation of the latest generation of non-Pt/C fuel cell electrocatalysts into high-performance electrodes in proton-exchange membrane fuel cells (PEMFCs). In this work, PtNi nanowire (NW) array gas diffusion electrodes (GDEs) are fabricated from Pt NW arrays with Ni impregnation. A 2.84-fold improvement in the oxygen reduction reaction catalytic activity is observed for the PtNi NW array GDE (cf. the Pt NW array GDE) using half-cell GDE measurement in a 0.1 M HClO4 aqueous electrolyte at 25 °C, in comparison to only a 1.07-fold power density recorded in the PEMFC single-cell test. An ionomer is shown to significantly increase the electrochemically active surface area of the GDEs, but the PtNi NW array GDE suffers from Ni ion contamination at a high temperature, contributing to decreased catalytic activities and limited improvement in operating PEMFCs.
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Affiliation(s)
- Peter Mardle
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
| | | | - Shaoliang Guan
- School of Chemistry, Cardiff University, Cardiff CF10 3AT, U.K
- HarwellXPS-The EPSRC National Facility for Photoelectron Spectroscopy, Research Complex at Harwell (RCaH), Didcot OX11 0FA, Oxon, U.K
| | - Yu-Lung Chiu
- School of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
| | - Shangfeng Du
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
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28
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Farzin S, Johnson TJ, Chatterjee S, Zamani E, Dishari SK. Ionomers From Kraft Lignin for Renewable Energy Applications. Front Chem 2020; 8:690. [PMID: 33005600 PMCID: PMC7480228 DOI: 10.3389/fchem.2020.00690] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/03/2020] [Indexed: 01/03/2023] Open
Abstract
Converting industrial/agricultural lignin-rich wastes to efficient, cost-effective materials for electrochemical devices (e.g., fuel cells) can aid in both bio- and energy economy. A major limitation of fuel cells is the weak ion conductivity within the ~2-30-nm thick, ion-conducting polymer (ionomer)-based catalyst-binder layer over electrodes. Here, we strategically sulfonated kraft lignin (a by-product of pulp and paper industries) to design ionomers with varied ion exchange capacities (IECs) (LS x; x = IEC) that can potentially overcome this interfacial ion conduction limitation. We measured the ion conductivity, water uptake, ionic domain characteristics, density, and predicted the water mobility/stiffness of Nafion, LS 1.6, and LS 3.1 in submicron-thick hydrated films. LS 1.6 showed ion conductivity an order of magnitude higher than Nafion and LS 3.1 in films with similar thickness. The ion conductivity of these films was not correlated to their water uptake and IECs. Within the three-dimensional, less dense, branched architecture of LS 1.6 macromolecules, the -SO3H and -OH groups are in close proximity, which likely facilitated the formation of larger ionic domains having highly mobile water molecules. As compared to LS 1.6, LS 3.1 showed a higher glass transition temperature and film stiffness at dry state, which sustained during humidification. On the contrary, Nafion stiffened significantly upon humidification. The smaller ionic cluster within stiff LS 3.1 and Nafion films thus led to ion conductivity lower than LS 1.6. Since LS x ionomers (unlike commercial lignosulfonate) are not water soluble, they are suitable for low-temperature, water-mediated ion conduction in submicron-thick films.
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Affiliation(s)
| | | | | | | | - Shudipto K. Dishari
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, NE, United States
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29
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Halabi M, Mann-Lahav M, Beilin V, Shter GE, Elishav O, Grader GS, Dekel DR. Electrospun Anion-Conducting Ionomer Fibers-Effect of Humidity on Final Properties. Polymers (Basel) 2020; 12:E1020. [PMID: 32369925 PMCID: PMC7284427 DOI: 10.3390/polym12051020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 04/27/2020] [Accepted: 04/27/2020] [Indexed: 11/16/2022] Open
Abstract
Anion-conducting ionomer-based nanofibers mats are prepared by electrospinning (ES) technique. Depending on the relative humidity (RH) during the ES process (RHES), ionomer nanofibers with different morphologies are obtained. The effect of relative humidity on the ionomer nanofibers morphology, ionic conductivity, and water uptake (WU) is studied. A branching effect in the ES fibers found to occur mostly at RHES < 30% is discussed. The anion conductivity and WU of the ionomer electrospun mats prepared at the lowest RHES are found to be higher than in those prepared at higher RHES. This effect can be ascribed to the large diameter of the ionomer fibers, which have a higher WU. Understanding the effect of RH during the ES process on ionomer-based fibers' properties is critical for the preparation of electrospun fiber mats for specific applications, such as electrochemical devices.
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Affiliation(s)
- Manar Halabi
- The Wolfson Department of Chemical Engineering, Technion−Israel Institute of Technology, Haifa 3200003, Israel; (M.H.); (M.M.-L.); (V.B.); (G.E.S.); (O.E.)
| | - Meirav Mann-Lahav
- The Wolfson Department of Chemical Engineering, Technion−Israel Institute of Technology, Haifa 3200003, Israel; (M.H.); (M.M.-L.); (V.B.); (G.E.S.); (O.E.)
| | - Vadim Beilin
- The Wolfson Department of Chemical Engineering, Technion−Israel Institute of Technology, Haifa 3200003, Israel; (M.H.); (M.M.-L.); (V.B.); (G.E.S.); (O.E.)
| | - Gennady E. Shter
- The Wolfson Department of Chemical Engineering, Technion−Israel Institute of Technology, Haifa 3200003, Israel; (M.H.); (M.M.-L.); (V.B.); (G.E.S.); (O.E.)
| | - Oren Elishav
- The Wolfson Department of Chemical Engineering, Technion−Israel Institute of Technology, Haifa 3200003, Israel; (M.H.); (M.M.-L.); (V.B.); (G.E.S.); (O.E.)
- The Nancy & Stephan Grand Technion Energy Program (GTEP), Technion, Israel Institute of Technology, Haifa 3200003, Israel
| | - Gideon S. Grader
- The Wolfson Department of Chemical Engineering, Technion−Israel Institute of Technology, Haifa 3200003, Israel; (M.H.); (M.M.-L.); (V.B.); (G.E.S.); (O.E.)
- The Nancy & Stephan Grand Technion Energy Program (GTEP), Technion, Israel Institute of Technology, Haifa 3200003, Israel
| | - Dario R. Dekel
- The Wolfson Department of Chemical Engineering, Technion−Israel Institute of Technology, Haifa 3200003, Israel; (M.H.); (M.M.-L.); (V.B.); (G.E.S.); (O.E.)
- The Nancy & Stephan Grand Technion Energy Program (GTEP), Technion, Israel Institute of Technology, Haifa 3200003, Israel
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30
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Uddin A, Dunsmore L, Zhang H, Hu L, Wu G, Litster S. High Power Density Platinum Group Metal-free Cathodes for Polymer Electrolyte Fuel Cells. ACS Appl Mater Interfaces 2020; 12:2216-2224. [PMID: 31850728 DOI: 10.1021/acsami.9b13945] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Low cost and high-performing platinum group metal-free (PGM-free) cathodes have the potential to transform the economics of polymer electrolyte fuel cell (PEFC) commercialization. Significant advancements have been made recently in terms of PGM-free catalyst activity and stability. However, before PGM-free catalysts become viable in PEFCs, several technical challenges must be addressed including cathode's fabrication, ionomer integration, and transport losses. Here, we present an integrated optimization of cathode performance that was achieved by simultaneously optimizing the catalyst morphology and electrode structure for high power density. The chemically doped metal-organic framework derived Fe-N-C catalyst we used allows precise tuning of the particle size over a wide range, enabling this unique study. Our results demonstrate the careful interplay between the catalyst primary particle size and the polymer electrolyte ionomer integration. The primary particles must be sufficiently large to permit uniform ionomer thin films throughout the surrounding pores, but not so large as to impact intraparticle transport to the active sites. The content of ionomer must be carefully balanced between sufficient loading for the complete catalyst coverage and adequate proton conductivity, while not being excessive and inducing large oxygen transport losses and liquid water flooding. With the optimal 100 nm size catalyst and ionomer loading, we achieved a high power density of 410 mW/cm2 at a rated voltage and a peak power density of 610 mW/cm2 in an automotive-relevant operating condition.
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Affiliation(s)
- Aman Uddin
- Department of Mechanical Engineering , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Lisa Dunsmore
- Department of Mechanical Engineering , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Hanguang Zhang
- Department of Chemical and Biological Engineering , University at Buffalo, The State University of New York , Buffalo , New York 14260 , United States
| | - Leiming Hu
- Department of Mechanical Engineering , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Gang Wu
- Department of Chemical and Biological Engineering , University at Buffalo, The State University of New York , Buffalo , New York 14260 , United States
| | - Shawn Litster
- Department of Mechanical Engineering , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
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31
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Khandavalli S, Park JH, Kariuki NN, Zaccarine SF, Pylypenko S, Myers DJ, Ulsh M, Mauger SA. Investigation of the Microstructure and Rheology of Iridium Oxide Catalyst Inks for Low-Temperature Polymer Electrolyte Membrane Water Electrolyzers. ACS Appl Mater Interfaces 2019; 11:45068-45079. [PMID: 31697470 DOI: 10.1021/acsami.9b14415] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We present an investigation of the structure and rheological behavior of catalyst inks for low-temperature polymer electrolyte membrane water electrolyzers. The ink consists of iridium oxide (IrO2) catalyst particles and a Nafion ionomer dispersed in a mixture of 1-propanol and water. The effects of ionomer concentration and catalyst concentration on the microstructure of the catalyst ink were studied. Studies on dilute inks (0.1 wt % IrO2) using zeta potential and dynamic light scattering measurements indicated a strong adsorption of the ionomer onto the catalyst particles which resulted in an increase in the ζ-potential and the z-average diameter. Steady-shear and dynamic-oscillatory-shear rheological measurements of concentrated IrO2 dispersions (35 wt % IrO2) indicated that the particles are strongly agglomerated in the absence of the ionomer. The addition of even a small amount of the ionomer (2.4 wt % with respect to total solids) caused the rheology to transition from shear thinning to Newtonian because of the reduction in agglomerated structure due to stabilization of the aggregates by the ionomer, consistent with the behavior of dilute inks. At intermediate ionomer loadings, between 2.4 and 9 wt %, the viscosity increased with increasing ionomer wt %, though remained Newtonian, predominantly due to the increasing ionomer volume fraction in the ink. For ionomer loadings greater than 9 wt %, the particles were found to be flocculated, likely induced by a dispersed ionomer. The flocculated inks exhibited strong shear-thinning and gel-like behaviors in steady-shear and oscillatory-shear rheology. The onset of flocculation was found to be sensitive to the catalyst concentration, where below 35 wt % of IrO2, flocculation was not observed. The rheological observations were further verified by ultra-small-angle X-ray scattering.
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Affiliation(s)
- Sunilkumar Khandavalli
- Chemistry and Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - Jae Hyung Park
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Nancy N Kariuki
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Sarah F Zaccarine
- Department of Chemistry , Colorado School of Mines , Golden , Colorado 80401 , United States
| | - Svitlana Pylypenko
- Department of Chemistry , Colorado School of Mines , Golden , Colorado 80401 , United States
| | - Deborah J Myers
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Michael Ulsh
- Chemistry and Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - Scott A Mauger
- Chemistry and Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
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32
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Pramounmat N, Loney CN, Kim C, Wiles L, Ayers KE, Kusoglu A, Renner JN. Controlling the Distribution of Perfluorinated Sulfonic Acid Ionomer with Elastin-like Polypeptide. ACS Appl Mater Interfaces 2019; 11:43649-43658. [PMID: 31644259 DOI: 10.1021/acsami.9b11160] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Proton-exchange-membrane (PEM)-based devices are promising technologies for hydrogen production and electricity generation. Currently, the amount of expensive platinum catalyst used in these devices must be reduced to be cost-competitive with other technologies. These devices typically contain Nafion ionomer thin films in the catalyst layers, which are responsible for transporting protons and gaseous species to and from electrochemically active sites. The morphology of the Nafion ionomer thin films in the catalyst layers with reduced platinum loading is impacted by interactions with the catalyst and the confinement to nanometer thicknesses, which leads to performance losses in PEM-based devices. In this study, an elastin-like polypeptide (ELP) is designed to modulate the morphology of Nafion ionomer on platinum surfaces. The ELP shows an ability to assemble into a monolayer on platinum and change the ionomer interaction with platinum, thereby modifying its thin-film structure and improving the Nafion ionomer coverage. As a proof of concept, an ELP-modified catalyst ink was prepared and morphological differences were observed. Overall, we discovered an engineered ELP that can modulate the ionomer-catalyst interface in the electrodes of PEM-based devices.
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Affiliation(s)
- Nuttanit Pramounmat
- Department of Chemical and Biomolecular Engineering , Case Western Reserve University , Cleveland , Ohio 44106 , United States
| | - Charles N Loney
- Department of Chemical and Biomolecular Engineering , Case Western Reserve University , Cleveland , Ohio 44106 , United States
| | - ChulOong Kim
- Department of Chemical and Biomolecular Engineering , Case Western Reserve University , Cleveland , Ohio 44106 , United States
| | - Luke Wiles
- Nel Hydrogen Inc. , 10 Technology Drive , Wallingford , Connecticut 06492 , United States
| | - Katherine E Ayers
- Nel Hydrogen Inc. , 10 Technology Drive , Wallingford , Connecticut 06492 , United States
| | - Ahmet Kusoglu
- Energy Conversion Group, Energy Technologies Area , Lawrence Berkeley National Laboratory , 1 Cyclotron Road, MS70-108B , Berkeley , California 94720 , United States
| | - Julie N Renner
- Department of Chemical and Biomolecular Engineering , Case Western Reserve University , Cleveland , Ohio 44106 , United States
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33
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Oh DK, Nguyen DT, Lee S, Ko P, Heo GS, Yun CH, Ha TW, Youn H, Ok JG. Facile and Scalable Fabrication of Flexible Reattachable Ionomer Nanopatterns by Continuous Multidimensional Nanoinscribing and Low-temperature Roll Imprinting. ACS Appl Mater Interfaces 2019; 11:12070-12076. [PMID: 30843383 DOI: 10.1021/acsami.8b21915] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We develop a facile route to the scalable fabrication of flexible reattachable ionomer nanopatterns (RAINs) by continuous nanoinscribing and low-temperature roll imprinting, which are repeatedly attachable to and detachable from arbitrarily shaped surfaces. First, by sequentially performing continuous nanoinscribing over a polymer substrate along the multiple directions, we readily create the multidimensional nanopattern, which otherwise demands complex nanofabrication. After its transfer to an elastomer pad for use as a soft nanoimprinting stamp, we then conduct a low-temperature roll imprinting of the ionomer film to fabricate a flexible and highly transparent RAIN. Reversible loosening of ionic units in the ionomer material at the mild temperature as low as ∼60-70 °C enables the faithful nanopatterning over thermosensitive organic compounds and fragile materials under a slight pressure. The excellent adhesion purely emerging from ionic interactions uniquely realizes the conformal attachability and clean detachability of RAINs for universal targets in ambient conditions, particularly beneficial for individual wearable and mobile devices requiring the user-specific "on/off" of the nanopattern-driven functionalities. As one vivid example, we demonstrate that a single light-emitting device can be switched from the focused pointer to the widespread flashlight depending on the RAIN application upon user's purpose.
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Affiliation(s)
- Dong Kyo Oh
- Department of Mechanical and Automotive Engineering , Seoul National University of Science and Technology , Seoul 01811 , Korea
| | - Dang Thuan Nguyen
- Department of Mechanical Engineering , Hanbat National University , Daejeon 34158 , Korea
| | - Seungjo Lee
- Department of Mechanical and Automotive Engineering , Seoul National University of Science and Technology , Seoul 01811 , Korea
| | - Pyeongsam Ko
- Department of Mechanical Engineering , Hanbat National University , Daejeon 34158 , Korea
| | - Gi-Seok Heo
- Center for Nano-Photonics Convergence Technology , Korea Institute of Industrial Technology , Gwangju 61012 , Korea
| | - Chang-Hun Yun
- Center for Nano-Photonics Convergence Technology , Korea Institute of Industrial Technology , Gwangju 61012 , Korea
| | - Tae-Won Ha
- Center for Nano-Photonics Convergence Technology , Korea Institute of Industrial Technology , Gwangju 61012 , Korea
| | - Hongseok Youn
- Department of Mechanical Engineering , Hanbat National University , Daejeon 34158 , Korea
| | - Jong G Ok
- Department of Mechanical and Automotive Engineering , Seoul National University of Science and Technology , Seoul 01811 , Korea
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Khandavalli S, Park JH, Kariuki NN, Myers DJ, Stickel JJ, Hurst K, Neyerlin KC, Ulsh M, Mauger SA. Rheological Investigation on the Microstructure of Fuel Cell Catalyst Inks. ACS Appl Mater Interfaces 2018; 10:43610-43622. [PMID: 30525374 DOI: 10.1021/acsami.8b15039] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present a rheological investigation of fuel cell catalyst inks. The effects of ink parameters, which include carbon black-support structure, Pt presence on carbon support (Pt-carbon), and ionomer (Nafion) concentration, on the ink microstructure of catalyst inks were studied using rheometry in combination with ultrasmall-angle X-ray scattering (USAXS) and dynamic light scattering (DLS). Dispersions of a high-surface-area carbon (HSC), or Ketjen black type, demonstrated a higher viscosity than Vulcan XC-72 carbon due to both a higher internal porosity and a more agglomerated structure that increased the effective particle volume fraction of the inks. The presence of Pt catalyst on both the carbon supports reduced the viscosity through electrostatic stabilization. For carbon-only dispersions (without Pt), the addition of ionomer up to a critical concentration decreased the viscosity due to electrosteric stabilization of carbon agglomerates. However, with Pt-carbon dispersions, the addition of ionomer showed contrasting behavior between Vulcan and HSC supports. In the Pt-Vulcan dispersions, the effect of ionomer addition on the rheology was qualitatively similar to Vulcan dispersions without Pt. The Pt-HSC dispersions showed an increased viscosity with ionomer addition and a strong shear-thinning nature, indicating that Nafion likely flocculated the Pt-HSC aggregates. These results were verified using DLS and USAXS. Further, the observations of the effect of ionomer:carbon ratio and a comparison between carbons of different surface areas provided insights on the microstructure of the catalyst ink corresponding to the optimized I/ C ratio for fuel cell performance reported in the literature.
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Affiliation(s)
- Sunilkumar Khandavalli
- Chemistry and Nanoscience Department , National Renewable Energy Laboratory , 15013 Denver West Parkway , Golden , Colorado 80401 , United States
| | - Jae Hyung Park
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Nancy N Kariuki
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Deborah J Myers
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Jonathan J Stickel
- National Bioenergy Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - Katherine Hurst
- Chemistry and Nanoscience Department , National Renewable Energy Laboratory , 15013 Denver West Parkway , Golden , Colorado 80401 , United States
| | - K C Neyerlin
- Chemistry and Nanoscience Department , National Renewable Energy Laboratory , 15013 Denver West Parkway , Golden , Colorado 80401 , United States
| | - Michael Ulsh
- Chemistry and Nanoscience Department , National Renewable Energy Laboratory , 15013 Denver West Parkway , Golden , Colorado 80401 , United States
| | - Scott A Mauger
- Chemistry and Nanoscience Department , National Renewable Energy Laboratory , 15013 Denver West Parkway , Golden , Colorado 80401 , United States
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Peng F, Zhao Z, Xia X, Cakmak M, Vogt BD. Enhanced Impact Resistance of Three-Dimensional-Printed Parts with Structured Filaments. ACS Appl Mater Interfaces 2018; 10:16087-16094. [PMID: 29658697 DOI: 10.1021/acsami.8b00866] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Net-shape manufacture of customizable objects through three-dimensional (3D) printing offers tremendous promise for personalization to improve the fit, performance, and comfort associated with devices and tools used in our daily lives. However, the application of 3D printing in structural objects has been limited by their poor mechanical performance that manifests from the layer-by-layer process by which the part is produced. Here, this interfacial weakness is overcome using a structured, core-shell polymer filament where a polycarbonate (PC) core solidifies quickly to define the shape, whereas an olefin ionomer shell contains functionality (crystallinity and ionic) that strengthen the interface between the printed layers. This structured filament leads to improved dimensional accuracy and impact resistance in comparison to the individual components. The impact resistance from structured filaments containing 45 vol % shell can exceed 800 J/m. The origins of this improved impact resistance are probed using X-ray microcomputed tomography. Energy is dissipated by delamination of the shell from PC near the crack tip, whereas PC remains intact to provide stability to the part after impact. This structured filament provides tremendous improvements in the critical properties for manufacture and represents a major leap forward in the impact properties obtainable for 3D-printed parts.
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Affiliation(s)
- Fang Peng
- Department of Polymer Engineering , University of Akron , Akron , Ohio 44325 , United States
| | - Zhiyang Zhao
- Department of Polymer Engineering , University of Akron , Akron , Ohio 44325 , United States
| | - Xuhui Xia
- Department of Polymer Engineering , University of Akron , Akron , Ohio 44325 , United States
| | - Miko Cakmak
- Departments of Materials Engineering and Mechanical Engineering , Purdue University , West Lafayette , Indiana 47907 , United States
| | - Bryan D Vogt
- Department of Polymer Engineering , University of Akron , Akron , Ohio 44325 , United States
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Li S, Terao K, Sato T. Colloidal Dispersion of a Perfluorosulfonated Ionomer in Water⁻Methanol Mixtures. Polymers (Basel) 2018; 10:polym10010072. [PMID: 30966107 PMCID: PMC6414853 DOI: 10.3390/polym10010072] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 01/05/2018] [Accepted: 01/10/2018] [Indexed: 11/18/2022] Open
Abstract
We have investigated the dispersion state of a perfluorosulfonated ionomer (PFSI; Nafion®) in aqueous dispersion and the effect of methanol (MeOH) added to the aqueous dispersion by small-angle X-ray scattering (SAXS) as well as static and dynamic light scattering (SLS and DLS, respectively). Although both electrostatic and hydrophobic interactions of PFSI are expected to be strong in the dispersions, SAXS profiles obtained were satisfactorily fitted by the spherical particle model of a bimodal molar mass distribution. The rod-like aggregate model proposed in previous papers was denied at least for the present PFSI dispersion. Although the SAXS profiles exhibited a weak peak and the auto-correlation functions of DLS showed a log-time decay by the “repulsive cage effect” due to the long-ranged electrostatic interaction among PFSI particles, the concentration dependence of SLS results was probably normal because the cancellation of the electrostatic and hydrophobic interactions. The addition of MeOH into the aqueous dispersion of PFSI weakened both the hydrophobic and electcrostatic interactions of PFSI, and it is rather difficult to classify whether MeOH is a good or poor solvent (dispersant) for PFSI.
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Affiliation(s)
- Sinan Li
- Department of Macromolecular Science, Osaka University, Toyonaka Osaka 560-0043, Japan.
| | - Ken Terao
- Department of Macromolecular Science, Osaka University, Toyonaka Osaka 560-0043, Japan.
| | - Takahiro Sato
- Department of Macromolecular Science, Osaka University, Toyonaka Osaka 560-0043, Japan.
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Lopez-Perez PM, da Silva RMP, Strehin I, Kouwer PHJ, Leeuwenburgh SCG, Messersmith PB. Self-healing hydrogels formed by complexation between calcium ions and bisphosphonate-functionalized star-shaped polymers. Macromolecules 2017; 50:8698-8706. [PMID: 29403089 DOI: 10.1021/acs.macromol.7b01417] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Star-shaped poly(ethylene glycol) (PEG) chain termini were functionalized with alendronate to create transient networks with reversible crosslinks upon addition of calcium ions. The gelation ability of alendronate-functionalized PEG was greatly dependent on the number of arms and arm molecular weight. After mixing polymer and calcium solutions, the formed hydrogels could be cut and then brought back together without any visible interface. After 2 minutes of contact, their connection was strong enough to allow for stretching without tearing through the previous fracture surface. Oscillatory rheology showed that the hydrogels recovered between 70 and 100% of the original storage and loss modulus after rupture. Frequency sweep measurements revealed a liquid-like behavior at lower frequencies and solid-like at high frequencies. Shifting frequency curves obtained at different calcium and polymer concentrations, all data collapsed in a single common master curve. This time-concentration superposition reveals a common relaxation mechanism intrinsically connected to the calcium-bisphosphonate complexation equilibrium.
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Affiliation(s)
- Paula M Lopez-Perez
- Biomedical Engineering Department, Materials Science and Engineering Department, Chemical and Biological Engineering Department, Chemistry of Life Processes Institute, Institute for Bionanotechnology in Medicine, Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Evanston, IL, USA.,Department of Biomaterials, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ricardo M P da Silva
- Centre for Craniofacial and Regenerative Biology, King's College London, London, SE1 9RT, UK
| | - Iossif Strehin
- Biomedical Engineering Department, Materials Science and Engineering Department, Chemical and Biological Engineering Department, Chemistry of Life Processes Institute, Institute for Bionanotechnology in Medicine, Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Evanston, IL, USA
| | - Paul H J Kouwer
- Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
| | | | - Phillip B Messersmith
- Biomedical Engineering Department, Materials Science and Engineering Department, Chemical and Biological Engineering Department, Chemistry of Life Processes Institute, Institute for Bionanotechnology in Medicine, Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Evanston, IL, USA.,Departments of Bioengineering and Materials Science and Engineering, University of California, Berkeley, CA, USA
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38
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Wang Y, Liu J, Zhu Y, Zhu D, Chen H. Formation and Characterization of Dendritic Interfacial Electrodes inside an Ionomer. ACS Appl Mater Interfaces 2017; 9:30258-30262. [PMID: 28841281 DOI: 10.1021/acsami.7b08012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Formation of dendritic interfacial electrodes (DIEs) between metal/polymer interfaces has high demands in a variety of areas. By combining impregnation electroplating (IEP) step with impregnation-reduction (IR) step under straightforward conditions, we report a novel method of preparation of dendritic interfacial metal electrodes of palladium, platinum, silver and copper inside an ionomer for ionic polymer-metal composites (IPMC) application. The depth of palladium DIEs can be controlled by adjusting the reaction time, and the maximum depth can almost reach up to contact from the both sides of ionomer with a total thickness of 200 μm. The capacitance and actuation performance of IPMC was dramatically enhanced because of the presence of DIEs.
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Affiliation(s)
- Yanjie Wang
- School of Mechanical and Electrical Engineering, Hohai University, Changzhou Campus , Changzhou 213022, People's Republic of China
| | - Jiayu Liu
- Department of Mechanical Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Yetao Zhu
- School of Mechanical and Electrical Engineering, Hohai University, Changzhou Campus , Changzhou 213022, People's Republic of China
| | - Denglin Zhu
- School of Mechanical and Electrical Engineering, Hohai University, Changzhou Campus , Changzhou 213022, People's Republic of China
| | - Hualing Chen
- School of Mechanical Engineering, Xi'an Jiaotong University , Xi'an 710049, People's Republic of China
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Wang K, Zhang Z, Liu C, Fu Q, Xu W, Huang C, Weiss RA, Gong X. Efficient Polymer Solar Cells by Lithium Sulfonated Polystyrene as a Charge Transport Interfacial Layer. ACS Appl Mater Interfaces 2017; 9:5348-5357. [PMID: 28116895 DOI: 10.1021/acsami.6b13642] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this paper, we report the highly efficient bulk heterojunction (BHJ) polymer solar cells (PSCs) with an inverted device structure via utilizing an ultrathin layer of lithium sulfonated polystyrene (LiSPS) ionomer to reengineer the surface of the solution-processed zinc oxide (ZnO) electron extraction layer (EEL). The unique lithium-ionic conductive LiSPS contributes to enhanced electrical conductivity of the ZnO/LiSPS EEL, which not only facilitates charge extraction from the BHJ active layer but also minimizes the energy loss within the charge transport processes. In addition, the organic-inorganic LiSPS ionomer well circumvents the coherence issue of the organic BHJ photoactive layer on the ZnO EEL. Consequently, the enhanced charge transport and the lowered internal resistance between the BHJ photoactive layer and the ZnO/LiSPS EEL give rise to a dramatically reduced dark saturation current density and significantly minimized charge carrier recombination. As a result, the inverted BHJ PSCs with the ZnO/LiSPS EEL exhibit an approximatively 25% increase in power conversion efficiency. These results indicate our strategy provides an easy, but effective, approach to reach high performance inverted PSCs.
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Affiliation(s)
- Kai Wang
- Department of Polymer Engineering, College of Polymer Science and Polymer Engineering, The University of Akron , Akron, Ohio 44325, United States
| | - Zhan Zhang
- Department of Polymer Engineering, College of Polymer Science and Polymer Engineering, The University of Akron , Akron, Ohio 44325, United States
| | - Chang Liu
- Department of Polymer Engineering, College of Polymer Science and Polymer Engineering, The University of Akron , Akron, Ohio 44325, United States
| | - Qiang Fu
- Department of Polymer Engineering, College of Polymer Science and Polymer Engineering, The University of Akron , Akron, Ohio 44325, United States
| | - Wenzhan Xu
- Department of Polymer Engineering, College of Polymer Science and Polymer Engineering, The University of Akron , Akron, Ohio 44325, United States
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, P. R. China
| | - Chongwen Huang
- Department of Polymer Engineering, College of Polymer Science and Polymer Engineering, The University of Akron , Akron, Ohio 44325, United States
| | - R A Weiss
- Department of Polymer Engineering, College of Polymer Science and Polymer Engineering, The University of Akron , Akron, Ohio 44325, United States
| | - Xiong Gong
- Department of Polymer Engineering, College of Polymer Science and Polymer Engineering, The University of Akron , Akron, Ohio 44325, United States
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, P. R. China
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Morris DRP, Liu SP, Villegas Gonzalez D, Gostick JT. Effect of water sorption on the electronic conductivity of porous polymer electrolyte membrane fuel cell catalyst layers. ACS Appl Mater Interfaces 2014; 6:18609-18618. [PMID: 25275957 DOI: 10.1021/am503509j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A method is described for measuring the effective electronic conductivity of porous fuel cell catalyst layers (CLs) as a function of relative humidity (RH). Four formulations of CLs with different carbon black (CB) contents and ionomer equivalent weights (EWs) were tested. The van der Pauw method was used to measure the sheet resistance (RS), which increased with RH for all samples. The increase was attributed to ionomer swelling upon water uptake, which affects the connectivity of CB aggregates. Greater increases in RS were observed for samples with lower EW, which uptake more water on a mass basis per mass ionomer. Transient RS measurements were taken during absorption and desorption, and the resistance kinetics were fit using a double exponential decay model. No hysteresis was observed, and the absorption and desorption kinetics were virtually symmetric. Thickness measurements were attempted at different RHs, but no discernible changes were observed. This finding led to the conclusion that the conducting Pt/C volume fraction does not change with RH, which suggests that effective medium theory models that depend on volume fraction alone cannot explain the reduction in conductivity with RH. The merits of percolation-based models were discussed. Optical micrographs revealed an extensive network of "mud cracks" in some samples. The influence of water sorption on CL conductivity is primarily explained by ionomer swelling, and its effects on the quantity and quality of interaggregate contacts were discussed.
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Affiliation(s)
- David R P Morris
- Department of Chemical Engineering, McGill University , H3A 2B2 Montreal, Québec, Canada
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