Poly(fluorene)‐Based Anion Exchange Membrane Demonstrating Excellent Durability at 1.5 A cm^‒2 for 2400 h in Water Electrolyzers

Abstract

Abstract Anion exchange membrane water electrolyzer (AEMWE) is a cost‐effective alternative to proton exchange membrane water electrolyzer for green hydrogen production. However, AEMWE commercialization is hindered primarily by the lack of a reliable anion exchange membrane (AEM) for long‐term cell durability. In this study, a poly(fluorene)‐based PFAA‐QA AEM is developed with a simple structure, exhibiting satisfactory OH − conductivity (>174.6 mS cm −1 at 80 °C), good mechanical properties (tensile strength >35 MPa and elongation at break >51%), and excellent alkaline stability (>2000 h in 3 m KOH at 80 °C). These characteristics allow PFAA‐QA‐based AEMWEs to demonstrate a high cell performance (3.95 A cm −2 at 70 °C and 1.95 V) and long‐term durability at high current densities (1.5 A cm −2 for 2400 h at 70 °C). Therefore, the durability of these AEMWEs surpasses that of most AEMWEs with a low voltage decay rate (>29 mV kh −1 ).