Review and Perspectives of the In Situ Modification Strategy for Bifunctional Electrodes in a Vanadium Redox Flow Battery

A vanadium redox flow battery (VRFB) represents the most commercially advanced and mature technology among redox flow batteries presently available. However, the catalytic activity of the original electrode material significantly hinders the energy efficiency of the vanadium ion redox reactions. Therefore, improving the electrodes is imperative to enhance the performance of the battery. VRFB commercialization is facilitated by the utilization of bifunctional electrodes acquired through in situ modification techniques. This approach enhances the performance of both the positive and negative electrodes, thereby increasing the efficiency of the battery. This study provides a summary of research concerning bifunctional electrodes acquired through in situ modification, including acid treatment, electrochemical treatment, heat treatment, and some novel methods. Furthermore, the application and challenges associated with bifunctional electrodes in VRFB are also outlined. This review concludes with a perspective on the future trajectory of VRFB development, elucidating the direction of its commercial advancement.