Electrolyte Engineering for Long‐Term Stable Anion Exchange Membrane Water Electrolysis

Abstract Anion exchange membrane water electrolysis (AEM‐WE) has emerged as a promising technology for green hydrogen production, offering advantages such as high energy efficiency and compatibility with intermittent renewable energy sources. However, maintaining stable operation at high current densities to minimize energy consumption requires the development of more active and durable catalysts, along with the optimization of interfacial interaction between the electrode with electrolyte. In this study, Fe ²⁺ into NiFe layered double hydroxides (LDHs) is incorporated to synthesize a highly active NiFe ²⁺ Fe ³⁺ ‐LDHs anode, which demonstrated excellent performance with required voltages of 1.64 V at 1.0 A cm ⁻² and 2.0 V at 4.2 A cm ⁻² . Then, through comprehensive screening of various anions (PO ₄ ³⁻ , B(OH) ₄ ⁻ , CO ₃ ²⁻ , and SO ₄ ²⁻ ) as potential electrolyte additives, phosphate ions are employed to reduce the electrolyzer degradation rate to 87 µV h ⁻¹ over 120 h at 3.0 A cm ⁻² . This work presents a dual strategy involving the design of an intrinsically active anode material and the establishment of an anion‐based protective layer to inhibit dissolution, thereby enhancing both the energy efficiency and operational longevity of AEM water electrolysis systems.