High‐Performance Poly(biphenyl acetylpyridine) and Poly(ether ketone cardo) Blend Membranes for High‐Temperature Polymer Electrolyte Membrane Fuel Cells

Abstract Developing high‐temperature polymer electrolyte membranes with sufficient performance and competitive cost is a major scientific checkpoint for promoting the popularization of fuel cells. Herein, poly(biphenyl acetylpyridine) (PBAP) is synthesized by a facile one‐pot Friedel‐Crafts polymerization between 4‐acetylpyridine and biphenyl. The PBAP has excellent solubility in polar solvents, while its membrane shows a significantly high phosphoric acid (PA) absorption capacity due to the presence of amounts of pyridine groups. However, the pure PBAP membrane is dissolved in 85 wt.% PA solution. In order to solve excessive expansion and poor mechanical stability, a series of PBAP blend membranes are fabricated by mixing PBAP with commercial engineering thermoplastic of poly(ether ketone cardo) (PEKC). Blending PEKC significantly improves the dimensional and mechanical stabilities. In particular, blend membranes exhibit remarkable chemical stability as documented by Fenton test, while membranes after Fenton test display slightly higher acid uptakes and conductivities. As a result, the PBAP‐50wt.%PEKC/170%PA membrane shows a conductivity of 0.051 S cm −1 at 160 °C and mechanical strength of 8.3 MPa at 25 °C. The peak power density at 160 °C of the H 2 ‐O 2 single cell with above membrane is 632 mW cm −2 , indicating the potential of PBAP‐ x %PEKC/PA membranes for fuel cells.