Akademik Veri Yönetim Sistemi
International Journal of Hydrogen Energy, cilt.48, sa.17, ss.6638-6656, 2023 (SCI-Expanded)
© 2021 Hydrogen Energy Publications LLCOperating proton exchange membrane fuel cells (PEMFCs) at higher temperatures (above the boiling point of water) offer several advantages. It enhances the electrodes' kinetics, allows the recovery of useful heat, and offers better water management due to the formation of water in the vapor phase. There is a crucial need to either, modify the existing perfluorosulfonic acid membranes (i.e. Nafion) or develop a new class of membranes that can withstand higher temperature operation. Heteropolyacids (HPAs) represent a class of inorganic materials that have been investigated as additives in PEMFCs membranes for the purpose of: 1) enhancing the proton conductivity and, 2) reducing the fuel crossover. This review focuses on discussing the recent developments attained upon the introduction of HPAs in proton exchange membranes. The review summarized the various efforts made on either modifying the existing Nafion membranes with HPAs, or by immobilizing them in other polymers such as PBI and SPEEK. Remarkable enhancements in proton conductivities, as well as a significant reduction in fuel crossover, were reported. However, the leaching of HPAs is still a major obstacle. The current review concludes that the successful implementation of HPAs in PEMFCs membranes can be achieved upon developing proper immobilization techniques within the polymers' matrix.