Highly Hydrophilic Zirconia Composite Anion Exchange Membrane for Water Electrolysis and Fuel Cells

To prepare anion exchange membranes with high water electrolysis and single fuel cell performance, an inorganic–organic composite (IOC) strategy with click cross-linked membranes coated with different contents of hydrophilic polar nanozirconia is proposed to fabricate composite membranes (CM) PBP-SH-Zrx. The performance test results showed that the CM PBP-SH-Zr4 not only has good through-plane ionic conductivity (167.7 mS cm^–1, 80 °C), but also exhibits satisfactory dimensional stability (SR 16.5%, WU 206.4%, 80 °C), especially demonstrating excellent alkaline stability with only 16% degradation (2 M NaOH for 2200 h). In water electrolysis, the “microgap” between the membrane and catalyst layer (solid–solid interface) is alleviated, and the membrane electrode assembly (MEA) interfacial compatibility (liquid–solid–solid interface) is enhanced. The CM PBP-SH-Zr4 showed the lowest charge transfer resistance (R_ct, 0.037 Ω cm²) and a high current density of 2.5 A cm^–2 at 2.2 V, while the voltage drop was 0.361 mV h^–1 after 360 h of endurance (six start–stop cycles) at 60 °C and 500 mA cm^–2, proving a good water electrolysis durability. Moreover, an acceptable peak power density of 0.464 W cm^–2 at 80 °C is achieved in a H₂/O₂ fuel cell with a PBP-SH-Zr4-AEM. Therefore, the IOC strategy can enhance the membrane’s comprehensive performance and interface compatibility of MEA and may promote the development of anion exchange membranes (AEMs) for water electrolysis and fuel cells.