Highly durable and efficient anion exchange membrane water electrolyzer using one-step fabrication of the integrated electrode by the hot-press process

Herein, we develop a commercial-scale anion exchange membrane (AEM) water electrolyzer with exceptional durability that employs a Co oxide anode and commercial Pt/C cathode. The anode of the AEM water electrolyzer was developed using a simplified one-step hot-pressing process utilizing a single-phase Co oxide to achieve a uniform electrode surface and simplify the fabrication process. The Co oxide electrode obtained at the optimal hot-pressing temperature of 250 °C, exhibited excellent durability and catalytic activity compared to electrodes synthesized at other temperatures. This can be attributed to its spinel structure and the presence of Co³⁺ as the primary active site for the oxygen evolution reaction. The AEM water electrolyzer demonstrated remarkable performance, with a high hydrogen production efficiency of 79.46% and ultra-low degradation rate of only 2 mV kh⁻¹ during a long-term durability test of 1000 h at 50 °C. These results indicate the exceptional potential of the AEM water electrolyzer comprising a Co oxide anode as a promising technology for efficient and sustainable production of high-purity hydrogen.