Impact of ionomer-free anode electrodes on mass transport and durability of proton exchange membrane water electrolyzer

초록

The advancement of durable and efficient anode electrodes is indispensable for enhancing of proton exchange membrane water electrolysis (PEMWE) as a sustainable hydrogen production technology. Herein, we investigate the design of an ionomer-free anode electrode, featuring IrRuOx nanoparticles encapsulated within a carbon shell and supported on carbon nanofibers (CNF) (IrRuOx@CS/CNF), directly integrated onto titanium porous transport layers (IrRuOx@CS/CNF-Ti). Compared to the traditional ionomer-containing electrode (IrRuOx@CS/CNF-P), the ionomer-free electrode highlights superhydrophilic surface behaviors, which markedly enhance interfacial wettability, mass transport, and catalytic effectiveness. Comprehensive characterizations of electrocatalyst confirm the formation of uniformly distributed IrRuOx nanoparticles, revealing comparable size, chemical composition, and oxidation states in both anode electrodes, with wettability emerging as the one contributing factor for performance. During unit-cell PEMWE testing, the IrRuOx@CS/CNF-Ti electrode demonstrates superior activity, achieving over 3.51 A/cm2 at 1.8 V cell voltage, surpassing the U.S. DOE 2026 target. Furthermore, it exhibits considerably reduced overpotentials, lower charge-transfer resistance, and excellent stability with a degradation rate of only approximately 100 mu V/h during 100 h operation, outperforming both IrRuOx@CS/CNFP and commercial IrO2. These findings highlight the pivotal role of electrode wettability in governing mass transport dynamics and durability, and establish ionomer-free superhydrophilic electrodes as a promising pathway toward high-performance, cost-effective PEMWE systems.

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