Ion migration and gas diffusion are two of the most critical topics in water electrolysis. Many self-supported electrodes (SSEs) exhibit efficient performance in fundamental research studies due to their excellent gas diffusion. However, such performance is not guaranteed in large-scale electrolyzers due to the extremely large ion-migration resistance of these SSEs. Here we find that a commercial SSE (Ni foam) exhibits efficient performance in fundamental research but performs poorly in an anion exchange membrane water electrolyzer (AEMWE). Further investigations reveal that the poor performance of the AEMWE originates from the large ion-migration resistance caused by the long OH⁻ migration distance within the SSE. After its design is optimized to minimize the ion-migration resistance and enhance gas-diffusion efficiency, the AEMWE is found to deliver a current density of 1 A/cm² at 1.778 V in 1 M KOH at 65 °C. A triple-cell stack is further assembled and found to reach 1 A/cm² at 5.464 V and to exhibit excellent stability over 216 h in 1 M KOH, showing its good potential for scalable production.

中文翻译：

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合理的自支撑电极设计，具有优化的离子迁移和气体扩散，适用于高效的阴离子交换膜水电解槽


离子迁移和气体扩散是电解水中最关键的两个主题。许多自支撑电极 （SSE） 由于其出色的气体扩散性，在基础研究中表现出高效的性能。然而，由于这些 SISE 的离子迁移电阻非常大，因此在大型电解槽中无法保证这种性能。在这里，我们发现商业 SSE（泡沫镍）在基础研究中表现出有效的性能，但在阴离子交换膜水电解槽 （AEMWE） 中表现不佳。进一步的研究表明，AEMWE 性能不佳是由于 SSE 内较长的 OH⁻ 迁移距离导致较大的离子迁移电阻。在优化其设计以最大限度地降低离子迁移阻力并提高气体扩散效率后，发现 AEMWE 在 65 °C 下在 1.778 V 和 1 M KOH 下可提供 1 A/cm² 的电流密度。 进一步组装三电池堆，发现在 5.464 V 下达到 1 A/cm²，并在 1 M KOH 中表现出超过 216 小时的出色稳定性，显示出其可扩展的良好潜力。