Compression‐Guided Formation of Interlocked Membrane–Electrode Interfaces Using Nickel Sponge for Anion Exchange Membrane Electrolysis

Abstract Three‐dimensional membrane–electrode assemblies (MEAs) are widely used to improve gas transport and electrochemical performance in high‐current‐density anion exchange membrane water electrolysis (AEMWE). While simple compression offers a scalable route to form such structures, mismatch between rigid electrodes and weak membranes hampers reliable integration. This challenge is addressed by a nanofibrous nickel sponge that interlocks with pre‐swollen membranes under direct compression, forming a conformal, void‐free 3D MEA without complex or thermal processing. The sponge features a resilient fibrous architecture produced via a one‐pot wet process with trace iridium or iron precursors, ensuring catalytic function and reproducibility. With only 0.4 wt.% Ir, the Ni–Ir sponge achieves hydrogen evolution overpotentials of 18.2, 43.0, and 260 mV at 10, 100, and 1000 mA cm −2 . The Ni–Fe sponge delivers oxygen evolution overpotentials of 184, 236, and 324 mV, outperforming nickel‐foam–based benchmarks. The pressure‐optimized single stack achieves 1.3 and 3.7 A cm −2 at 1.8 and 2.0 V in 1 M KOH at 80 °C, demonstrating durable ampere‐scale hydrogen production for over 1200 h with minimal degradation. This direct compression‐induced interlocked MEA strategy overcomes interfacial and manufacturing barriers, enabling scalable integration for practical high‐current AEMWE.