Polybenzimidazole modification composite

Trogadas and Ramani summarized the modification of PEM membranes, including Nafion modified by zirconium phosphates, heteropolyacids, hydrogen sulfates, metal oxides, and silica. Membranes with sulfonated non-fluorinated backbones were also described. The base polymers polysulfone, poly(ether sulfone), poly(ether ether ketone), polybenzimidazole, and polyimide. Another interesting category is acid-base polymer blend membranes. This review also paid special attention to electrode designs based on catalyst particles bound by a hydrophobic poly-tetrafluoroethylene (PTFE) structure or hydrophilic Nafion, vacuum deposition, and electrodeposition method. Issues related to the MEA were presented. In then-study on composite membranes, the effects of particle sizes, cation sizes, number of protons, etc., of HPA were correlated with the fuel cell performance. To promote stability of the PTA within the membrane matrix, the investigators have employed PTA supported on metal oxides such as silicon dioxide as additives to Nafion. 

Nafion-based hybrid membranes are traditionally used electrolytes for both PEM fuel cell and DMFCs. " Besides Nafion, many composite engineering thermoplastic polymers based on poly(etheretherketone) (PEEK), polyvinyl alcohol (PVA), polysulfone, " polybenzimidazole (PBI), polyimide, and other organic-inorganic composite membranes have been employed as alternative membranes for both PEM fuel cells and DMFCs due to their lower cost, comparable conductivity, high mechanical and thermal stabilities, and easy modification as well. 

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