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Wakolo SW, Syouji A, Sakai M, Nishiyama H, Inukai J. Coherent anti-Stokes Raman scattering spectroscopy system for observation of water molecules in anion exchange membrane. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 309:123875. [PMID: 38217988 DOI: 10.1016/j.saa.2024.123875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 12/30/2023] [Accepted: 01/06/2024] [Indexed: 01/15/2024]
Abstract
Anion exchange membrane fuel cells (AEMFCs) provide one of the most feasible remedies to fuel cells' dependency on the dwindling Pt group catalysts. Nevertheless, AEMFCs still suffer reduced durability, which requires an in-depth understanding of their membranes. The low thermal endurance of the anion exchange membranes (AEMs) usually limits the direct application of powerful techniques, such as Raman spectroscopy. We sought to establish a system for coherent anti-Stokes Raman scattering (CARS) spectroscopy capable of taking measurements inside an AEM rapidly and accurately without photodamage. A 785 nm CARS system was newly developed to study the water species in an AEM (QPAF-4) located vertically in a fuel cell. From the results of water measurement in a QPAF-4 membrane, the OH-related region was deconvoluted into nine Gaussian peaks: Five H-bonded OH peaks, non-H-bonded OH, OH-, and two CH peaks. The H-bonded species increased with increasing relative humidity, but the other species remained constant. These results open unlimited possibilities for studying and comparing different AEMFCs, enabling more rapid technology optimization.
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Affiliation(s)
- Solomon Wekesa Wakolo
- Integrated Graduate School of Medicine, Engineering, and Agricultural Sciences, University of Yamanashi, 4-4-37 Takeda, Kofu, Yamanashi 400-8510, Japan
| | - Atsushi Syouji
- Center for Basic Education in Faculty of Engineering, University of Yamanashi, 4-4-37 Takeda, Kofu, Yamanashi 400-8510, Japan
| | - Masaru Sakai
- Faculty of Engineering, Graduate Faculty of Interdisciplinary Research, University of Yamanashi, 4-4-37 Kofu, Yamanashi 400-8510, Japan
| | - Hiromichi Nishiyama
- Hydrogen and Fuel Cell Nanomaterials Center, University of Yamanashi, 6-43 Miyamae, Kofu, Yamanashi 400-0021, Japan.
| | - Junji Inukai
- Hydrogen and Fuel Cell Nanomaterials Center, University of Yamanashi, 6-43 Miyamae, Kofu, Yamanashi 400-0021, Japan; Clean Energy Research Center, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8510, Japan.
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Wakolo SW, Tryk DA, Nishiyama H, Miyatake K, Iiyama A, Inukai J. Various states of water species in an anion exchange membrane characterized by Raman spectroscopy under controlled temperature and humidity. Phys Chem Chem Phys 2024; 26:1658-1670. [PMID: 38009441 DOI: 10.1039/d3cp03660j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2023]
Abstract
Anion exchange membrane fuel cells (AEMFCs) hold the key to future mass commercialisation of fuel cell technology, even though currently, AEMFCs perform less optimally than proton exchange membrane fuel cells (PEMFCs). Unlike PEMFCs, AEMFCs have demonstrated the capability to operate independently of Pt group metal-based catalysts. Water characterization inside the membrane is one factor that significantly influences the performance of AEMFCs. In this paper, different water species inside an anion exchange membrane (AEM), QPAF-4, developed at the University of Yamanashi, were studied for the first time using micro-Raman spectroscopy. Spectra of pure water, alkaline solutions, and calculations based on density functional theory were used to identify the water species in the AEM. The OH stretching band was deconvoluted into nine unique Gaussian bands. All the hydrogen-bonded OH species increased steadily with increasing humidity, while the CH and non-H-bonded OH remained relatively constant. These results confirm the viability of micro-Raman spectroscopy in studying the various water-related species in AEMs. The availability of this technique is an essential prerequisite in improving the ionic conductivity and effectively solving the persisting durability challenge facing AEMFCs, thus hastening the possibility of mass commercialisation of fuel cells.
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Affiliation(s)
- Solomon Wekesa Wakolo
- Integrated Graduate School of Medicine, Engineering, and Agricultural Sciences, University of Yamanashi, 4-3-37 Takeda, Kofu, Yamanashi 400-8510, Japan
| | - Donald A Tryk
- Hydrogen and Fuel Cell Nanomaterials Research Center, University of Yamanashi, 6-43 Miyamae, Kofu, Yamanashi 400-0021, Japan.
| | - Hiromichi Nishiyama
- Hydrogen and Fuel Cell Nanomaterials Research Center, University of Yamanashi, 6-43 Miyamae, Kofu, Yamanashi 400-0021, Japan.
| | - Kenji Miyatake
- Hydrogen and Fuel Cell Nanomaterials Research Center, University of Yamanashi, 6-43 Miyamae, Kofu, Yamanashi 400-0021, Japan.
- Clean Energy Research Center, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8510, Japan
- Department of Applied Chemistry, Waseda University, Tokyo 169-8555, Japan
| | - Akihiro Iiyama
- Hydrogen and Fuel Cell Nanomaterials Research Center, University of Yamanashi, 6-43 Miyamae, Kofu, Yamanashi 400-0021, Japan.
| | - Junji Inukai
- Hydrogen and Fuel Cell Nanomaterials Research Center, University of Yamanashi, 6-43 Miyamae, Kofu, Yamanashi 400-0021, Japan.
- Clean Energy Research Center, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8510, Japan
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Chialvo AA. On the Elusive Links between Solution Microstructure, Dynamics, and Solvation Thermodynamics: Demystifying the Path through a Bridge over Troubled Conjectures and Misinterpretations. J Phys Chem B 2023; 127:10792-10813. [PMID: 38060479 DOI: 10.1021/acs.jpcb.3c04707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
We build a fundamentally based bridge between the solute-induced microstructural perturbation of the species environment and the dynamic as well as thermodynamic responses of the fluid system, regardless of the state conditions, composition, nature of the solvent, and either the magnitude or the type of solute-solvent intermolecular-interaction asymmetries. For that purpose, we advance a fluctuation-based solvation formalism of fluid mixtures to provide meaningful descriptors of solvation phenomena, the microstructural signatures of their solute-solvent intermolecular interaction asymmetry, and the thermodynamic manifestations linked to the solution nonideality. The rigorous foundations afford us to address some crucial issues frequently invoked in the literature including the microstructural perturbation domain, its proper identification and molecular-based meaning toward the interpretation of the solvation process, and the potential impact of the local differential behavior between anions and cations on the actual salt-induced perturbation of the solvent microstructure. Indeed, we link the precisely characterized species solvation behavior to fundamental thermodynamic residual-property relations, and the dynamics associated with either the viscous flow or diffusive behavior of the solvent, to finally illustrate their outcome with experimental data of aqueous electrolyte solutions from the available literature. Ultimately, this effort provides a highly desirable unambiguous identification of the cause-effect connections between the microstructurally perturbed domains and the experimentally measured macroscopic solvation properties, including their effect on the dynamics of the solvent environment. More importantly, it lends a well-established solvation framework to bridge rigorously the microstructural details of the mixture, its dynamics, and its solvation thermodynamics to enhance our understanding of well-defined ranked Hofmeister series, i.e., by avoiding ad hoc conjectures and unsupported microscopic interpretations of solvation phenomena.
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Affiliation(s)
- Ariel A Chialvo
- Retired Scientist, Knoxville, Tennessee 37922-3108, United States
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Leong KW, Pan W, Yi X, Luo S, Zhao X, Zhang Y, Wang Y, Mao J, Chen Y, Xuan J, Wang H, Leung DY. Next-generation magnesium-ion batteries: The quasi-solid-state approach to multivalent metal ion storage. SCIENCE ADVANCES 2023; 9:eadh1181. [PMID: 37556543 PMCID: PMC10411913 DOI: 10.1126/sciadv.adh1181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 07/06/2023] [Indexed: 08/11/2023]
Abstract
Mg-ion batteries offer a safe, low-cost, and high-energy density alternative to current Li-ion batteries. However, nonaqueous Mg-ion batteries struggle with poor ionic conductivity, while aqueous batteries face a narrow electrochemical window. Our group previously developed a water-in-salt battery with an operating voltage above 2 V yet still lower than its nonaqueous counterpart because of the dominance of proton over Mg-ion insertion in the cathode. We designed a quasi-solid-state magnesium-ion battery (QSMB) that confines the hydrogen bond network for true multivalent metal ion storage. The QSMB demonstrates an energy density of 264 W·hour kg-1, nearly five times higher than aqueous Mg-ion batteries and a voltage plateau (2.6 to 2.0 V), outperforming other Mg-ion batteries. In addition, it retains 90% of its capacity after 900 cycles at subzero temperatures (-22°C). The QSMB leverages the advantages of aqueous and nonaqueous systems, offering an innovative approach to designing high-performing Mg-ion batteries and other multivalent metal ion batteries.
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Affiliation(s)
- Kee Wah Leong
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Wending Pan
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Xiaoping Yi
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Shijing Luo
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Xiaolong Zhao
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Yingguang Zhang
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Yifei Wang
- School of Mechanical Engineering and Automation, Harbin Institute of Technology, Shenzhen 510006, China
| | - Jianjun Mao
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Yue Chen
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Jin Xuan
- Department of Chemical and Process Engineering, University of Surrey, Surrey GU2 7XH, UK
| | - Huizhi Wang
- Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Dennis Y. C. Leung
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
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Stefanutti E, Bove LE, Alabarse FG, Lelong G, Bruni F, Ricci MA. Vibrational dynamics of confined supercooled water. J Chem Phys 2019; 150:224504. [PMID: 31202218 DOI: 10.1063/1.5094147] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The quest for a possible liquid-liquid coexistence line in supercooled water below its homogeneous nucleation temperature is faced by confining water within a porous silica substrate (MCM-41). This system is investigated by synchrotron radiation infrared spectroscopy, exploring both the intramolecular and the intermolecular vibrational dynamics, in the temperature range from ambient down to ∼120 K, along several isobaric paths between 0.7 kbar and 3.0 kbar. Upon lowering the temperature, the OH-stretching band shows that the intramolecular vibrational dynamics continuously evolves from predominantly liquidlike to predominantly icelike. An abrupt change in the line shape of the intermolecular vibrational band between 220 K and 240 K, depending on the pressure, is the signature of nucleation of ice within the MCM-41 pores. These findings do not support the presence of two liquid phases and provide evidence for the coexistence of liquid water and ice in water confined in MCM-41.
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Affiliation(s)
- E Stefanutti
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 4 Place Jussieu, 75005 Paris, France
| | - L E Bove
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 4 Place Jussieu, 75005 Paris, France
| | - F G Alabarse
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 4 Place Jussieu, 75005 Paris, France
| | - G Lelong
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 4 Place Jussieu, 75005 Paris, France
| | - F Bruni
- Dipartimento di Scienze, Università Degli Studi Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy
| | - M A Ricci
- Dipartimento di Scienze, Università Degli Studi Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy
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Drexler CI, Miller TC, Rogers BA, Li YC, Daly CA, Yang T, Corcelli SA, Cremer PS. Counter Cations Affect Transport in Aqueous Hydroxide Solutions with Ion Specificity. J Am Chem Soc 2019; 141:6930-6936. [DOI: 10.1021/jacs.8b13458] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
| | - Tierney C. Miller
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | | | | | - Clyde A. Daly
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | | | - Steven A. Corcelli
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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Stefanski J, Schmidt C, Jahn S. Aqueous sodium hydroxide (NaOH) solutions at high pressure and temperature: insights from in situ Raman spectroscopy and ab initio molecular dynamics simulations. Phys Chem Chem Phys 2018; 20:21629-21639. [PMID: 30101256 DOI: 10.1039/c8cp00376a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrothermal diamond anvil cell experiments in combination with Raman spectroscopy and first principles molecular dynamics simulations were performed to investigate the structure and dynamics of aqueous NaOH solutions for temperatures up to 700 °C, pressures up to 850 MPa and two different solute concentrations. The significant changes observed in the O-H stretching region of the Raman spectra between ambient and supercritical conditions are explained by both dynamic effects and structural differences. Especially important are a Grotthuss-like proton transport process and the decreasing network connectivity of the water molecules with increasing temperature. The observed transfer of Raman intensity towards lower wavenumbers by the proton transfer affects a wide range of frequencies and must be considered in the interpretation of Raman spectra of highly basic solutions. We suggest a deconvolution of the spectra using a model with four Gaussian functions, which are assigned to the molecular H2O and OH- vibrations, and one asymmetric exponentially modified Gaussian (EMG) function, which is assigned to [HO(H2O)n]- vibrations.
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Affiliation(s)
- Johannes Stefanski
- Institute of Geology and Mineralogy, University of Cologne, Zülpicher Straße 49b, 50674 Köln, Germany.
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