Monomers, Polymers and Cross-Linked Membranes for Membrane Fuel Cells and Electrolysis

Abstract

This contribution comprises an overview in the development of ionomers/ionomer (blend) membranes for fuel cells. The topics include the development of novel sulfonated monomers and homoand copolymers; the preparation of ionically cross-linked membranes prepared by mixing these polymers with different polybenzimidazoles (PBI); the application of these membranes to PEFC and DMFC; development of novel base-excess PBI/sulfonated polymer/H 3 PO 4 blend membranes, and test of these membranes in fuel cells at intermediate fuel cell operation temperatures (170-200°C). These membranes have been tested in a DMFC. The i/U polarization curves of the membranes showed a better performance than Nafion ® . Acid-base blend membranes were also applied to the HyS electrolysis process, showing good stability and electrolysis performance. Phosphonated polymers and ternary blend membranes for the application in intermediate T fuel cells have been developed as well. These membranes showed good chemical stability rivalling that of pure PBI membranes.

Thermo-Stable Non-PFSA Cation-Conductive Fluoropolymers for Medium-Temperature PEMFCs

“…In the past, extensive efforts have been focused on developing novel cation-exchange membranes that can tolerate medium-range temperatures. For example, phosphoric aciddoped polybenimidazole (PBI) membranes were examined for medium-temperature phosphoric acid fuel cells (11). Hybrid Nafion TM membranes doped with TiO 2 (12), imidazole (13), triazole (14), heteropolyacids (15), zirconia (13), zirconium phosphates (13), etc.…”