| POLYMERS Vol.72 No.11 |
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COVER STORY
Polymer Electrolyte Fuel Cell (PEFC) Today |
| COVER STORY: Highlight Reviews |
| The Role of Polymers, Membrane and Ionomer Used in PEFC | Akihiro SHINOHARA |
| <Abstract> Fuel cell vehicles (FCVs), which generate electrical energy from a chemical reaction between hydrogen and oxygen in the air, are expected to become widespread as a clean mobility. Two types of polymers, membranes and ionomers, are used in the polymer electrolyte fuel cells (PEFCs) installed in FCVs. Both polymers require high proton conductivity over a wide temperature range and durability to cope with the long-term operation of FCVs. However, for gas permeation, membranes require low gas permeability while ionomers require high gas permeability. Therefore, their design concepts are different. This article presents the role of these polymers and their required functions. It also suggests the improved polymer abilities required for advanced PEFCs around 2040. Keywords: Fuel Cell / Polymer Electrolyte / Membrane / Ionomer / Catalyst Layer |
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| Polymer Nanofiber Composite Electrolyte Membrane for Fuel Cell | Hiroyoshi KAWAKAMI |
| <Abstract> For fuel cells to become widely used, it is essential to achieve higher performance, higher durability, and lower cost of electrolyte membranes. However, since these three elements have a trade-off relationship, the creation of a new concept is required. The novel electrolyte membranes that are composed of polymer functional nanofiber frameworks and electrolyte polymers are attracting attention as novel membranes that can simultaneously achieve these three elements. Because the nanofibers are characterized by their ability to transport protons at their surface in addition to move protons inside the nanofibers, and these features have enabled their membranes to conduct protons rapidly over a wide temperature and humidity range. By developing their nanofiber frameworks based on a novel proton transport mechanism, the candidate we developed has succeeded in improving membrane durability over conventional membranes for fuel cell uses. In addition, these nanofiber frameworks have a potential as new polymer electrolyte membranes that can transport ions rapidly for all-solid-state Li-ion batteries or water electrolysis. Keywords: Fuel Cell / Polymer Electrolyte Membrane / Percolation Transport / Nanofiber Framework / Blend Nanofiber / Proton Conductivity |
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| Research and Development of Next-Generation Polymer Electrolyte Membranes | Atsushi NORO, Takato KAJITA |
| <Abstract> Polymer electrolyte membranes, which are one of the main components in polymer electrolyte fuel cells, exhibit high conductivities when used at lower temperatures than 100℃ under high humidity conditions. In this article, we review the current state of research on polymer electrolyte membranes that exhibit conductivities at higher temperatures than 100℃ under low humidity conditions, and propose guidelines or directions for the development of next-generation polymer electrolyte membranes that can be used at higher temperatures than 100℃ under low humidity conditions but withstand practical use. Keywords: Fuel Cell / Polymer Electrolyte Membrane / Proton Conductivity / Humidity / Carbon Nutrality / Green Transformation / Vinyl Polymer / Ion Exchange Capacity |
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| COVER STORY: Topics and Products |
| Importance of Gas Permeability of Polymer Electrolytes –For Durability and Fuel Cell Performance– | Masamichi NISHIHARA |
| <Abstract> Improvement of durability and performance on polymer electrolyte materials such as membranes (PEMs) and ionomers in fuel cells are critical issues for popularization of fuel cell technology. To solve strict targets, our group develops new ideas based on the mechanisms of chemical degradation and catalytic activity. These behaviors are strongly related to gas permeability of polymer electrolytes. In case of PEMs, oxygen permeation through PEMs is one of the reasons of PEM degradation. In case of ionomers, oxygen permeation through ionmers affects catalytic activity. Based on these facts, we developed new high gas barrier PEMs and high gas permeable ionomers. We could confirm the concept that high gas barrier PEMs show higher chemical durability than Nafion, and high gas permeable ionomers show higher performance than Nafion ionomer. These concepts are simple and applicable for many polymers, which could so far not be used in PEM and ionomer applications. We believe our concept will provide powerful tools for next generation fuel cell applications. Keywords: Polymer Electrolyte / Polymer Electrolyte Membrane (PEM) / Ionomer / Gas Permeability / PEM Durability / Performance / Fuel Cell |
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| Global Market Trends and Technical Targets of Fuel Cell Electric Vehicles | Masakazu YONEDA |
| <Abstract> The latest global market trends and technology targets of Fuel Cell Electric Vehicles (FCEVs) are reviewed. In the heavy duty transportations, FCEVs are considered superior to Battery Electric Vehicles (BEVs) in terms of cruising range and energy charging time, so the hydrogen fuel cell is expected to be used as a powertrain for trucks, railroads, ships, construction machinery, and agricultural machinery. Recently, a technology development roadmap was announced for the full-scale spread of FC trucks in the future from New Energy and Industrial Technology Development Organization (NEDO), and targets for high performance and durability of FC stacks are presented. In this roadmap, in order to achieve the ambitious targets, the polymer electrolyte is required to improve proton conductivity in a wide temperature range ensuring long-term durability. Furthermore, countermeasures against Per- and PolyFluoroAlkyl Substances (PFAS) regulations are becoming a new issue. Keywords: FCEV / Market / Technical Target |
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| Fluorinated Polymer Electrolyte for PEFCs | Takeshi HIRAI |
| <Abstract> Perfluorinated sulfonic acid polymers (PFSAs) are essential materials in modern society as they are the only suitable materials for use in membranes for chlor-alkali electrolysis, a process that produces caustic soda and chlorine, which are essential raw materials in the chemical industry. PFSAs are also used in proton exchange membranes, a critical component of polymer electrolyte fuel cells (PEFCs). The development of PFSAs with high durability and proton transport performance have contributed to the practical use of PEFCs. However, there are still challenges particularly those used in heavy-duty vehicles, such as the need for high chemical durability, proton conductivity at high temperatures, the development of tough and thin membranes, and the design of next-generation ionomers that have high oxygen permeability and low catalyst poisoning. The development of improved PFSAs can help to achieve high-performance and cost-effective PEFCs, contributing to the realization of a sustainable society. Keywords: Polymer Electrolyte Fuel Cell / Perfluorinated Sulfonic Acid Polymer / Chemical Stability / Radical Quencher / High Temperature Operation / Mechanical Durability / High Oxygen Permeable Ionomer |
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| Polymer Science and I: A Personal Account |
| Be an Expert in Synthesis | Yoshimasa MATSUMURA |
| <Abstract> I didn’t have a dream for my future when I was a child. However, my interest in chemistry led me to pursue graduate studies and become a chemist at the university. I want to continue my research and aim to develop into a reliable specialist in polymer synthesis. That is my dream now. |
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| Front-Line Polymer Science |
| Recent Research Trends on Photo-Functional Lanthanide Coordination Polymers | Yasuchika HASEGAWA |
| <Abstract> In recent years, studies on coordination polymers composed of metal ions and organic ligands have been actively pursued. Here, the latest research trends on the photo-functional lanthanide coordination polymers with abilities like “temperature sensors”, “pressure sensors”, and “metal ion and molecule sensors” are introduced. The latest research trends on amorphization and structural phase transition of coordination polymers with rigid structures are also demonstrated. Further studies on the photo-functional lanthanide coordination polymers is expected to open up a new frontier field of future science and technology. Keywords: Coordination Polymer / Lanthanide / Lumienscence / Emission / Sensor |
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