Zero-gap membrane electrode assembly (MEA) CO electrolyzer stands as a promising technology for circular carbon economy. However, current CO electrolyzers are energetically inefficient when operating at ampere-level current densities. Here, by analyzing the performance discrepancies between MEA and flow cells, we identify the depletion of K⁺ and water at the cathode as the main contributor to the low performance of MEA CO electrolyzers. This is attributed to the unique cathodic interface in catholyte-free MEA, where there is no aqueous electrolyte to maintain the three-phase interface. Through the development of needle-array catalysts with intensified electric fields (EFs) at their tips, we are able to concentrate the limited K⁺ cations onto the tips of the cathode, while simultaneously facilitating water uptake via electro-osmosis. We construct an MEA CO electrolyzer that achieves a large current density of 2,500 mA cm⁻² at a voltage of only 2.7 V.

中文翻译：

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脱水界面处膜电解槽中的场增强 CO 电还原


零间隙膜电极组件 （MEA） CO 电解槽是一种很有前途的循环碳经济技术。然而，目前的 CO 电解槽在安培级电流密度下运行时能量效率低下。在这里，通过分析 MEA 和流通池之间的性能差异，我们确定了阴极 K⁺ 和水的消耗是导致 MEA CO 电解槽性能低下的主要原因。这归因于无阴极 MEA 中独特的阴极界面，其中没有水性电解质来维持三相界面。通过开发尖端具有增强电场 （EF） 的针状催化剂，我们能够将有限的 K⁺ 阳离子集中在阴极的尖端，同时通过电渗透促进水分吸收。我们构建了一个 MEA CO 电解槽，在仅 2.7 V 的电压下实现了 2,500 mA ^cm-2 的大电流密度。