Ordered Armor Engineering Enabling Ten-Ampere-Level Performance for Anion Exchange Membrane Water Electrolyzers under an Ultrathin Membrane.

Abstract

The application of anion exchange membrane water electrolyzers (AEMWEs) is restricted by low performance, poor catalyst layer stability, and severe gas crossover. To address these challenges, we propose an ordered enhanced-armored membrane electrode assembly (En-Armored MEA) with a stable "cork-neck" structure, which is built by integrating a compression-tuned mesh as armor and a 3D-ordered array membrane together. Compared with the conventional MEA, this compact encapsulation significantly promotes the MEA from three aspects. First, the electrochemically active surface area (ECSA) is increased 4.5 times. Second, the in-plane resistance is reduced by 77.5%. Third, mass transfer is improved by directing bubble release. As a result, the En-Armored MEA boosts current density by 522% to a ten-Ampere-level performance of 15.83 ± 0.30 A/cm² at 2.0 V (80 °C, 1 M KOH) and maintains 1000 h durability at 1.5 A/cm² without decay. Notably, the highly interlocked "cork-neck" structure enables stable operation with ultrathin membranes down to 4 μm, whereas conventional MEAs suffer short circuits and severe hydrogen crossover below 15 μm because of the membrane pierced by Ni foam. This work presents an innovative MEA engineering strategy that combines "cork-neck" and armored structures together to greatly improve the performance, catalyst layer stability, and membrane integrity for AEMWEs and other membrane-based electrochemical energy devices.