Practical operating flexibility of a bifunctional freestanding membrane for efficient anion exchange membrane water electrolysis across all current ranges
Hong‐Jin Son,
Jeemin Hwang,
Min Young Choi,
Seung Hee Park,
Jae Hyuk Jang,
Byungchan Han,
Sung Hoon Ahn
Affiliations
Hong‐Jin Son
Department of Bio‐Chemical Engineering Chosun University Gwangju Republic of Korea
Jeemin Hwang
Fuel Cell Research and Demonstration Center, Hydrogen Energy Research Division Korea Institute of Energy Research (KIER) Buan‐gun Jeollabuk‐do Republic of Korea
Min Young Choi
Center for Research Equipment Korea Basic Science Institute Daejeon Republic of Korea
Seung Hee Park
Department of Bio‐Chemical Engineering Chosun University Gwangju Republic of Korea
Jae Hyuk Jang
Center for Research Equipment Korea Basic Science Institute Daejeon Republic of Korea
Byungchan Han
Department of Chemical and Biomolecular Engineering Yonsei University Seoul Republic of Korea
Sung Hoon Ahn
Department of Bio‐Chemical Engineering Chosun University Gwangju Republic of Korea
Abstract This study explores a symmetric configuration approach in anion exchange membrane (AEM) water electrolysis, focusing on overcoming adaptability challenges in dynamic conditions. Here, a rapid and mild synthesis technique for fabricating fibrous membrane‐type catalyst electrodes is developed. Our method leverages the contrasting oxidation states between the sulfur‐doped NiFe(OH)2 shell and the metallic Ni core, as revealed by electron energy loss spectroscopy. Theoretical evaluations confirm that the S–NiFe(OH)2 active sites optimize free energy for alkaline water electrolysis intermediates. This technique bypasses traditional energy‐intensive processes, achieving superior bifunctional activity beyond current benchmarks. The symmetric AEM water electrolyzer demonstrates a current density of 2 A cm−2 at 1.78 V at 60°C in 1 M KOH electrolyte and also sustains ampere‐scale water electrolysis below 2.0 V for 140 h even in ambient conditions. These results highlight the system's operational flexibility and structural stability, marking a significant advancement in AEM water electrolysis technology.