Impact of high-frequency current ripples on LT-PEM fuel cells materials degradation

Résumé fourni par la source

The impact of high-frequency current ripples generated by power electronic on the degradation of membrane electrode assembly (MEA) materials is not yet understood. In this study, two single-cell aging tests were performed at 0.8 A cm −2 : one under constant current and one subjected to sinusoidal current ripples at 10 kHz (±20 % amplitude variation), with respective durations of 455 h and 504 h. Electrochemical properties were monitored through periodic operando characterizations, while post mortem structural, microstructural and chemical analyses were carried out on the aged MEAs after disassembly. Our results show that both aging protocols ultimately led to membrane failure through increased hydrogen crossover and short-circuit formation. Nevertheless, catalyst degradation (i.e., increase in Pt nanoparticles’ size) remained limited under both conditions and substantially lower than that observed during conventional catalyst accelerated stress tests. No chemical degradation of the membrane was detected, although X-ray tomography revealed localized mechanical cracking. Overall, under the investigated single-cell conditions, sinusoidal current ripples with an amplitude of ±20 % did not produce additional detectable MEA-component degradation relative to the constant-current baseline. This conclusion is restricted to the tested frequency range, operating point, MEA architecture and aging durations.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.