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Moehring NK, Naclerio AE, Chaturvedi P, Knight T, Kidambi PR. Ultra-thin proton conducting carrier layers for scalable integration of atomically thin 2D materials with proton exchange polymers for next-generation PEMs. NANOSCALE 2024; 16:6973-6983. [PMID: 38353333 DOI: 10.1039/d3nr05202h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
Scalable approaches for synthesis and integration of proton selective atomically thin 2D materials with proton conducting polymers can enable next-generation proton exchange membranes (PEMs) with minimal crossover of reactants or undesired species while maintaining adequately high proton conductance for practical applications. Here, we systematically investigate facile and scalable approaches to interface monolayer graphene synthesized via scalable chemical vapor deposition (CVD) on Cu foil with the most widely used proton exchange polymer Nafion 211 (N211, ∼25 μm thick film) via (i) spin-coating a ∼700 nm thin Nafion carrier layer to transfer graphene (spin + scoop), (ii) casting a Nafion film and cold pressing (cold press), and (iii) hot pressing (hot press) while minimizing micron-scale defects to <0.3% area. Interfacing CVD graphene on Cu with N211 via cold press or hot press and subsequent removal of Cu via etching results in ∼50% lower areal proton conductance compared to membranes fabricated via the spin + scoop method. Notably, the areal proton conductance can be recovered by soaking the hot and cold press membranes in 0.1 M HCl, without significant damage to graphene. We rationalize our finding by the significantly smaller reservoir for cation uptake from Cu etching for the ∼700 nm thin carrier Nafion layer used for spin + scoop transfer compared to the ∼25 μm thick N211 film for hot and cold pressing. Finally, we demonstrate performance in H2 fuel cells with power densities of ∼0.23 W cm-2 and up to ∼41-54% reduction in H2 crossover for the N211|G|N211 sandwich membranes compared to the control N211|N211 indicating potential for our approach in enabling advanced PEMs for fuel cells, redox-flow batteries, isotope separations and beyond.
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Affiliation(s)
- Nicole K Moehring
- Interdisciplinary Graduate Program in Materials Science, Vanderbilt University, Nashville, TN 37235, USA.
- Chemical and Biomolecular Engineering Department, Vanderbilt University, Nashville, TN 37212, USA
- Vanderbilt Institute of Nanoscale Science and Engineering, Nashville, TN 37212, USA
| | - Andrew E Naclerio
- Chemical and Biomolecular Engineering Department, Vanderbilt University, Nashville, TN 37212, USA
| | - Pavan Chaturvedi
- Chemical and Biomolecular Engineering Department, Vanderbilt University, Nashville, TN 37212, USA
- Vanderbilt Institute of Nanoscale Science and Engineering, Nashville, TN 37212, USA
| | - Thomas Knight
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
| | - Piran R Kidambi
- Interdisciplinary Graduate Program in Materials Science, Vanderbilt University, Nashville, TN 37235, USA.
- Chemical and Biomolecular Engineering Department, Vanderbilt University, Nashville, TN 37212, USA
- Vanderbilt Institute of Nanoscale Science and Engineering, Nashville, TN 37212, USA
- Mechanical Engineering Department, Vanderbilt University, Nashville, TN, 37212, USA
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2
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Srivastav H, Weber AZ, Radke CJ. Colloidal Stability of PFSA-Ionomer Dispersions Part II: Determination of Suspension pH Using Single-Ion Potential Energies. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:6666-6674. [PMID: 38498907 DOI: 10.1021/acs.langmuir.3c03904] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
Perfluorosulfonic acid (PFSA) ionomers serve a vital role in the performance and stability of fuel-cell catalyst layers. These properties, in turn, depend on the colloidal processing of precursor inks. To understand the colloidal structure of fuel-cell catalyst layers, we explore the aggregation of PFSA ionomers dissolved in water/alcohol solutions and relate the predicted aggregation to experimental measurements of solution pH. Not all side chains contribute to measured pH because of burying inside particle aggregates. To account for the measured degree of dissociation, a new description is developed for how PFSA aggregates interact with each other. The developed single-counterion electrostatic repulsive pair potential from Part I is incorporated into the Smoluchowski collision-based kinetics of interacting aggregates with buried side chains. We demonstrate that the surrounding solvent mixture affects the degree of aggregation as well as the pH of the system primarily through the solution dielectric permittivity, which drives the strength of the interparticle repulsive energies. Successful pH prediction of Nafion ionomer dispersions in water/n-propanol solutions validates the numerical calculations. Nafion-dispersion pH measurements serve as a surrogate for Nafion particle-size distributions. The model and framework can be leveraged to explore different ink formulations.
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Affiliation(s)
- Harsh Srivastav
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, 201 Gilman South Drive, Berkeley, California 94720, United States
- Energy Technologies Area, Lawrence Berkeley National Laboratory, Building 30, Cyclotron Road, Berkeley, California 94720, United States
| | - Adam Z Weber
- Energy Technologies Area, Lawrence Berkeley National Laboratory, Building 30, Cyclotron Road, Berkeley, California 94720, United States
| | - Clayton J Radke
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, 201 Gilman South Drive, Berkeley, California 94720, United States
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3
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Girod R, Lazaridis T, Gasteiger HA, Tileli V. Three-dimensional nanoimaging of fuel cell catalyst layers. Nat Catal 2023; 6:383-391. [PMID: 37252670 PMCID: PMC10212762 DOI: 10.1038/s41929-023-00947-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 03/14/2023] [Indexed: 05/31/2023]
Abstract
Catalyst layers in proton exchange membrane fuel cells consist of platinum-group-metal nanocatalysts supported on carbon aggregates, forming a porous structure through which an ionomer network percolates. The local structural character of these heterogeneous assemblies is directly linked to the mass-transport resistances and subsequent cell performance losses; its three-dimensional visualization is therefore of interest. Herein we implement deep-learning-aided cryogenic transmission electron tomography for image restoration, and we quantitatively investigate the full morphology of various catalyst layers at the local-reaction-site scale. The analysis enables computation of metrics such as the ionomer morphology, coverage and homogeneity, location of platinum on the carbon supports, and platinum accessibility to the ionomer network, with the results directly compared and validated with experimental measurements. We expect that our findings and methodology for evaluating catalyst layer architectures will contribute towards linking the morphology to transport properties and overall fuel cell performance.
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Affiliation(s)
- Robin Girod
- Institute of Materials, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Timon Lazaridis
- Chair of Technical Electrochemistry, Department of Chemistry and Catalysis Research Center, Technische Universität München, Garching, Germany
| | - Hubert A. Gasteiger
- Chair of Technical Electrochemistry, Department of Chemistry and Catalysis Research Center, Technische Universität München, Garching, Germany
| | - Vasiliki Tileli
- Institute of Materials, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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4
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Lee S, Hong S, Park J, Koh Y, Lee H, Yang J, Seo SW, Kim SJ. dCas9-Mediated PCR-Free Detection of Oncogenic Mutation by Nonequilibrium Nanoelectrokinetic Selective Preconcentration. Anal Chem 2023; 95:5045-5052. [PMID: 36893461 DOI: 10.1021/acs.analchem.2c05539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Cutting-edge nanoelectrokinetic technology in this work provides a breakthrough for the present clinical demands of molecular diagnosis to detect a trace amount of oncogenic mutation of DNA in a short time without an erroneous PCR procedure. In this work, we combined the sequence-specific labeling scheme of CRISPR/dCas9 and ion concentration polarization (ICP) mechanism to separately preconcentrate target DNA molecules for rapid detection. Using the mobility shift caused by dCas9's specific binding to the mutant, the mutated DNA and normal DNA were distinguished in the microchip. Based on this technique, we successfully demonstrated the dCas9-mediated 1-min detection of single base substitution (SBS) in EGFR DNA, a carcinogenesis indicator. Moreover, the presence/absence of target DNA was identified at a glance like a commercial pregnancy test kit (two lines for positive and one line for negative) by the distinct preconcentration mechanisms of ICP, even at the 0.1% concentration of the target mutant.
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Affiliation(s)
- Sangjun Lee
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Seongjun Hong
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Jihee Park
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Youngil Koh
- Department of Internal Medicine, Seoul National University Hospital, Seoul 03080, Republic of Korea
| | - Hyomin Lee
- Department of Chemical and Biological Engineering, Jeju National University, Jeju 63243, Republic of Korea
| | - Jina Yang
- Department of Chemical and Biological Engineering, Jeju National University, Jeju 63243, Republic of Korea
| | - Sang Woo Seo
- School of Chemical and Biological Engineering, Institute of Chemical Process, Seoul National University, Seoul 08826, Republic of Korea
| | - Sung Jae Kim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Republic of Korea
- SOFT Foundry Institute, Seoul National University, Seoul 08826, Republic of Korea
- Inter-university Semiconductor Research Center, Seoul National University, Seoul 08826, Republic of Korea
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5
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Long DM, Singh MK, Small KA, Watt J. Cryo-FIB for TEM investigation of soft matter and beam sensitive energy materials. NANOTECHNOLOGY 2022; 33:503001. [PMID: 36121746 DOI: 10.1088/1361-6528/ac92eb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 09/18/2022] [Indexed: 06/15/2023]
Abstract
Primarily driven by structural biology, the rapid advances in cryogenic electron microscopy techniques are now being adopted and applied by materials scientists. Samples that inherently have electron transparency can be rapidly frozen (vitrified) in amorphous ice and imaged directly on a cryogenic transmission electron microscopy (cryo-TEM), however this is not the case for many important materials systems, which can consist of layered structures, embedded architectures, or be contained within a device. Cryogenic focused ion beam (cryo-FIB) lift-out procedures have recently been developed to extract intact regions and interfaces of interest, that can then be thinned to electron transparency and transferred to the cryo-TEM for characterization. Several detailed studies have been reported demonstrating the cryo-FIB lift-out procedure, however due to its relative infancy in materials science improvements are still required to ensure the technique becomes more accessible and routinely successful. Here, we review recent results on the preparation of cryo-TEM lamellae using cryo-FIB and show that the technique is broadly applicable to a range of soft matter and beam sensitive energy materials. We then present a tutorial that can guide the materials scientist through the cryo-FIB lift-out process, highlighting recent methodological advances that address the most common failure points of the technique, such as needle attachment, lift-out and transfer, and final thinning.
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Affiliation(s)
- Daniel M Long
- Sandia National Laboratories, Albuquerque, NM 87123, United States of America
| | - Manish Kumar Singh
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
| | - Kathryn A Small
- Sandia National Laboratories, Albuquerque, NM 87123, United States of America
| | - John Watt
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States of America
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6
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Jiang X, Sun J, Zuckermann RN, Balsara NP. Effect of hydration on morphology of thin phosphonate block copolymer electrolyte membranes studied by electron tomography. POLYM ENG SCI 2021. [DOI: 10.1002/pen.25646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Xi Jiang
- Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley California USA
| | - Jing Sun
- Key Laboratory of Biobased Polymer Materials, Shandong Provincial Education Department, School of Polymer Science and Engineering Qingdao University of Science and Technology Qingdao China
| | - Ronald N. Zuckermann
- Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley California USA
- Molecular Foundry Lawrence Berkeley National Laboratory Berkeley California USA
| | - Nitash P. Balsara
- Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley California USA
- Department of Chemical and Biomolecular Engineering University of California Berkeley California USA
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7
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Jo A, Huet C, Naguib HE. Template-Assisted Self-Assembly of Conductive Polymer Electrodes for Ionic Electroactive Polymers. Front Bioeng Biotechnol 2020; 8:837. [PMID: 32850715 PMCID: PMC7412994 DOI: 10.3389/fbioe.2020.00837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 06/30/2020] [Indexed: 11/29/2022] Open
Abstract
Ionic electroactive polymers (ionic EAPs) can greatly aid in biomedical applications where micro-sized actuators are required for delicate procedures. Since these types of actuators generally require platinum or gold metallic electrodes, they tend to be expensive and susceptible to delamination. Previous research has solved this problem by replacing the metallic electrodes with conductive polymers (CP) and forming an interpenetrating polymer network (IPN) between the conductive polymer (CP) and the solid polymer electrolyte (SPE). Since these actuators contain toxic ionic liquids, they are unsuitable for biological applications. In this study, we present a novel and facile method of fabricating a biocompatible and ionic liquid-free actuator that uses semi-IPN to hold the CP and Nafion-based SPE layers together. Surface activated fabrication treatment (SAFT) is applied to the precursor-Nafion membrane in order to convert the sulfonyl fluoride groups on the surface to sulfonate. Through template-assisted self-assembly, the CP electrodes from either polyaniline (PANI) or poly(3,4-ethylenedioxythiophene) (PEDOT) interlock with the surface treated precursor-Nafion membrane so that no delamination can occur. The electrodes growth pattern, interfacial layer's thickness, and shape can be controlled by adjusting the SAFT concentration and duration.
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Affiliation(s)
- Andrew Jo
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Clémence Huet
- Department of Material Science and Engineering, Polytech Nantes, Nantes, France
| | - Hani E. Naguib
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
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8
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Martens I, Melo LGA, West MM, Wilkinson DP, Bizzotto D, Hitchcock AP. Imaging Reactivity of the Pt–Ionomer Interface in Fuel-Cell Catalyst Layers. ACS Catal 2020. [DOI: 10.1021/acscatal.0c01594] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Isaac Martens
- European Synchrotron Radiation Facility, Grenoble 38043, France
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Lis G. A. Melo
- Department of Chemistry & Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Marcia M. West
- Department of Chemistry & Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - David P. Wilkinson
- Department of Chemical Engineering, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Dan Bizzotto
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Adam P. Hitchcock
- Department of Chemistry & Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1, Canada
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9
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Zeng R, Zhang HY, Liang SZ, Wang LG, Jiang LJ, Liu XP. Possible scenario of forming a catalyst layer for proton exchange membrane fuel cells. RSC Adv 2020; 10:5502-5506. [PMID: 35498292 PMCID: PMC9049289 DOI: 10.1039/c9ra09864j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 01/22/2020] [Indexed: 11/21/2022] Open
Abstract
Ionomer in the catalyst layer provides an ion transport channel which is essential for many electrochemical devices. As the ionomer and electrochemical catalyst are packed together in the catalyst layer, it is difficult to have a clear image of the ionomer distribution in the catalyst layer and how the ionomer is in contact with Pt or carbon. A highly dispersed catalyst was deposited on the TEM SiN grid directly using the same (ultrasonic spray) or a similar way as the catalyst was deposited on the membrane. By analyzing the distribution of various elements (C, F, S, Pt etc.), we found that the ionomer may coexist in the catalyst layer in three ways: ionomer covered Pt particles due to the relatively strong interaction between Pt and the ionomer; ionomer covered C particles; packed free ionomer in between the aggregated catalyst particles. The results show that the ionomer is prone to covering the surface of Pt particles as further evidenced by the accelerated degradation test (ADT). Ionomer in the catalyst layer provides an ion transport channel which is essential for many electrochemical devices.![]()
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Affiliation(s)
- R. Zeng
- GRINM Group Co. Ltd
- Beijing
- P. R. China
- National Engineering Research Center of Nonferrous Metals Materials and Products for New Energy
- Beijing
| | - H. Y. Zhang
- GRINM Group Co. Ltd
- Beijing
- P. R. China
- National Engineering Research Center of Nonferrous Metals Materials and Products for New Energy
- Beijing
| | - S. Z. Liang
- GRINM Group Co. Ltd
- Beijing
- P. R. China
- National Engineering Research Center of Nonferrous Metals Materials and Products for New Energy
- Beijing
| | - L. G. Wang
- GRINM Group Co. Ltd
- Beijing
- P. R. China
- GRIMAT Engineering Institute Co., Ltd
- Beijing
| | - L. J. Jiang
- GRINM Group Co. Ltd
- Beijing
- P. R. China
- National Engineering Research Center of Nonferrous Metals Materials and Products for New Energy
- Beijing
| | - X. P. Liu
- GRINM Group Co. Ltd
- Beijing
- P. R. China
- National Engineering Research Center of Nonferrous Metals Materials and Products for New Energy
- Beijing
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10
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Melo LGA, Hitchcock AP. Electron beam damage of perfluorosulfonic acid studied by soft X-ray spectromicroscopy. Micron 2019; 121:8-20. [PMID: 30875488 DOI: 10.1016/j.micron.2019.02.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 02/08/2019] [Accepted: 02/19/2019] [Indexed: 10/27/2022]
Abstract
Scanning transmission X-ray microscopy (STXM) was used to study chemical changes to perfluorosulfonic acid (PFSA) spun cast thin films as a function of dose imparted by exposure of a 200 kV electron beam in a Transmission Electron Microscope (TEM). The relationship between electron beam fluence and absorbed dose was calibrated using a modified version of a protocol based on the positive to negative lithography transition in PMMA [Leontowich et al, J. Synchrotron Rad. 19 (2012) 976]. STXM was used to characterize and quantify the chemical changes caused by electron irradiation of PFSA under several different conditions. The critical dose for CF2-CF2 amorphization was used to explore the effects of the sample environment on electron beam damage. Use of a silicon nitride substrate was found to increase the CF2-CF2 amorphization critical dose by ∼x2 from that for free-standing PFSA films. Freestanding PFSA and PMMA films were damaged by 200 kV electrons at ∼100 K and then the damage was measured by STXM at 300 K (RT). The lithography cross-over dose for PMMA was found to be ∼2x higher when the PMMA thin film was electron irradiated at 120 K rather than at 300 K. The critical dose for CF2-CF2 amorphization in PFSA irradiated at 120 K followed by warming and delayed measurement by STXM at 300 K was found to be ∼2x larger than at 300 K. To place these results in the context of the use of electron microscopy to study PFSA ionomer in fuel cell systems, an exposure of 300 e-/nm2 at 300 K (which corresponds to an absorbed dose of ∼20 MGy) amorphizes ∼10% of the CF2-CF2 bonds in PFSA. At this dose level, the spatial resolution for TEM imaging of PFSA is limited to 3.5 nm by radiation damage, if one is using a direct electron detector with DQE = 1. This work recommends caution about 2D and 3D morphological information of PFSA materials based on TEM studies which use fluences higher than 300 e-/nm2.
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Affiliation(s)
- Lis G A Melo
- Dept. Chemistry and Chemical Biology, McMaster University, Hamilton, ON, L8S4M1, Canada.
| | - Adam P Hitchcock
- Dept. Chemistry and Chemical Biology, McMaster University, Hamilton, ON, L8S4M1, Canada
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11
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Abstract
In this comprehensive review, recent progress and developments on perfluorinated sulfonic-acid (PFSA) membranes have been summarized on many key topics. Although quite well investigated for decades, PFSA ionomers' complex behavior, along with their key role in many emerging technologies, have presented significant scientific challenges but also helped create a unique cross-disciplinary research field to overcome such challenges. Research and progress on PFSAs, especially when considered with their applications, are at the forefront of bridging electrochemistry and polymer (physics), which have also opened up development of state-of-the-art in situ characterization techniques as well as multiphysics computation models. Topics reviewed stem from correlating the various physical (e.g., mechanical) and transport properties with morphology and structure across time and length scales. In addition, topics of recent interest such as structure/transport correlations and modeling, composite PFSA membranes, degradation phenomena, and PFSA thin films are presented. Throughout, the impact of PFSA chemistry and side-chain is also discussed to present a broader perspective.
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Affiliation(s)
- Ahmet Kusoglu
- Energy Conversion Group, Energy Technologies Area, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, MS70-108B, Berkeley, California 94720, United States
| | - Adam Z Weber
- Energy Conversion Group, Energy Technologies Area, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, MS70-108B, Berkeley, California 94720, United States
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12
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Nanohybrids of graphene oxide chemically-bonded with Nafion: Preparation and application for proton exchange membrane fuel cells. J Memb Sci 2016. [DOI: 10.1016/j.memsci.2016.04.062] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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13
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Allen FI, Comolli LR, Kusoglu A, Modestino MA, Minor AM, Weber AZ. Morphology of Hydrated As-Cast Nafion Revealed through Cryo Electron Tomography. ACS Macro Lett 2015; 4:1-5. [PMID: 35596390 DOI: 10.1021/mz500606h] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nafion is an ion-containing random copolymer used as a solid electrolyte in many electrochemical applications thanks to its remarkable ionic conductivity and mechanical stability. Understanding the mechanism of ion transport in Nafion, which depends strongly on hydration, therefore requires a complete picture of its morphology in dry and hydrated form. Here we report on a nanoscale study of dry versus hydrated as-cast 100 nm Nafion membranes using analytical transmission electron microscopy (TEM) and cryogenic TEM tomography, respectively. For the dry membrane, spherical clusters ∼3.5 nm in diameter corresponding to the hydrophilic sulfonic-acid-containing phase are identified. In contrast, cryo TEM tomography of the hydrated membrane reveals an interconnected channel-type network, with a domain spacing of ∼5 nm, and presents the first nanoscale 3D views of the internal structure of hydrated Nafion obtained by a direct-imaging approach.
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Affiliation(s)
- Frances I. Allen
- Department of Materials Science and Engineering and ⊥Department of Chemical
and Biomolecular
Engineering, University of California, Berkeley, California 94720, United States
- National Center for Electron Microscopy, Molecular
Foundry, §Life
Sciences Division, and ∥Environmental
Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Luis R. Comolli
- Department of Materials Science and Engineering and ⊥Department of Chemical
and Biomolecular
Engineering, University of California, Berkeley, California 94720, United States
- National Center for Electron Microscopy, Molecular
Foundry, §Life
Sciences Division, and ∥Environmental
Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Ahmet Kusoglu
- Department of Materials Science and Engineering and ⊥Department of Chemical
and Biomolecular
Engineering, University of California, Berkeley, California 94720, United States
- National Center for Electron Microscopy, Molecular
Foundry, §Life
Sciences Division, and ∥Environmental
Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Miguel A. Modestino
- Department of Materials Science and Engineering and ⊥Department of Chemical
and Biomolecular
Engineering, University of California, Berkeley, California 94720, United States
- National Center for Electron Microscopy, Molecular
Foundry, §Life
Sciences Division, and ∥Environmental
Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Andrew M. Minor
- Department of Materials Science and Engineering and ⊥Department of Chemical
and Biomolecular
Engineering, University of California, Berkeley, California 94720, United States
- National Center for Electron Microscopy, Molecular
Foundry, §Life
Sciences Division, and ∥Environmental
Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Adam Z. Weber
- Department of Materials Science and Engineering and ⊥Department of Chemical
and Biomolecular
Engineering, University of California, Berkeley, California 94720, United States
- National Center for Electron Microscopy, Molecular
Foundry, §Life
Sciences Division, and ∥Environmental
Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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