N -Ethylcarbazole-Modified Poly(terphenyl piperidinium) Membranes and Systematic Membrane Electrode Assembly Optimization for High-Performance Alkaline Water Electrolysis

Anion exchange membrane water electrolysis (AEMWE) is critical for green hydrogen production, and its performance is tightly linked to membrane intrinsic properties and system-level optimization. Herein, N -ethylcarbazole-modified polyarylpiperidine anion exchange membranes (PCTP- x ) were synthesized via superacid-catalyzed condensation, with PCTP-10 (containing 10% N -ethylcarbazole) showing 63 mS cm −1 (20 °C) and 120 mS cm −1 (80 °C) OH – conductivity. To boost AEMWE performance, systematic membrane electrode assembly (MEA) fabrication optimization was implemented, encompassing three key strategies: adoption of the catalyst-coated substrate (CCS) method to minimize interfacial resistance, design of an asymmetric anode−cathode gasket thickness configuration, and selection of 80 °C as the operating temperature to enhance ionic conductivity. Under these conditions, PCTP-10-based AEMWE achieved 2000 mA cm −2 at 1.9 V, outperforming the reference PTP system (1600 mA cm −2 ). The PCTP-10 MEA also exhibited good stability, with a voltage decay rate of 0.45 mV h −1 over 350 h of operation. This study highlights the critical role of systematic MEA fabrication optimization in boosting the performance of AEMWE technologies for efficient green hydrogen production.