Efficient bubble removal in superhydrophilic gas diffusion electrodes via poly(vinyl alcohol) coating for high-current anion-exchange membrane water electrolysis

Abstract

Bubble-induced performance degradation caused by gas bubble accumulation, particularly at high current density, significantly hinders the performance of anion-exchange membrane water electrolysis (AEMWE). Herein, we present a simple and cost-effective strategy for enhancing mass transport in AEMWE: applying a hydrophilic polyvinyl alcohol (PVA) coating to carbon paper (CP) to create gas diffusion electrodes (GDEs). This simple and scalable GDE modification with enhanced hydrophilic and aerophobic properties promotes efficient bubble detachment and suppresses bubble-induced transport losses, resulting in improved GDE performance. The optimized PVA-coated GDE achieved a 35% improvement in cell performance compared to untreated bare CP GDEs, reaching a current density of 2.85 A cm⁻² at 2 V. Additionally, the PVA-coated GDE exhibited sustained operational stability, maintaining stable operation for over 100 h. These findings offer a practical approach to mitigating bubble-induced performance degradation and highlight the importance of electrode-level transport engineering for high-performance AEMWE hydrogen production.