Anion Exchange Membrane Based on Cross-Linked Poly(2,6-dimethyl-1,4-phenylene oxide)/Poly(dimethylaminophenyl bisdiphenol) for Fuel Cell Applications

Anion exchange membranes (AEMs) as an essential electrolyte material having high hydroxide ion conductivity, strong alkaline stability, and outstanding single-cell performance are in great demand for use in anion exchange membrane fuel cells (AEMFCs). This article reports the synthesis and characterization of cross-linked AEMs based on poly(2,6-dimethyl-1,4-phenylene oxide) and poly(dimethylaminophenyl bisdiphenol) for AEMFC applications. The morphological, thermal, chemical, mechanical, and electrochemical properties of cross-linked AEMs are systematically investigated. Notably, the optimized P-BDB-14 μm membrane achieves a hydroxide conductivity of 88.9 mS cm^-1 at 90 °C. The AEMFC single-cell performance utilizing the P-BDB-14 μm membrane reaches a peak power density (PPD) of 294.2 mW cm^-2 when operating with H₂/air at 60 °C. In contrast, the P-BDB-40 μm membrane achieves a hydroxide conductivity of 65.7 mS cm^-1 at 90 °C and maintains a PPD of 128 mW cm^-2 in H₂/air under the same fuel cell temperature and open-circuit voltage conditions for 500 min. Therefore, this study demonstrates that the AEMs based on cross-linked poly(2,6-dimethyl-1,4-phenylene oxide)/poly(dimethylaminophenyl bisdiphenol) hold significant potential as efficient anion exchange membranes for use in fuel cell applications.