Redox Mediator Chemistry Regulated Aqueous Batteries: Insights into Mechanisms and Prospects

Abstract

Redox mediators (RMs), serving as intermediate electron carriers or reservoirs, play vital roles in developing new charge transfer energy storage systems with high voltage or capacity in aqueous batteries. However, the underlying mechanism and selection criteria of RMs remain unclear in aqueous batteries, which hinders the further exploitation of new RMs and aqueous battery chemistries. Herein, rather than simply compiling recent progress, we critically appraise the potential correlation between the electrochemical charge storage mechanisms and the selection criteria of RMs. For practical applications, current challenges and promising strategies are synergistically proposed, corresponding to representative applications in holistic deposition- dissolution aqueous batteries, sulfur-based aqueous batteries, and redox flow aqueous batteries. Last, this perspective provides synergistic concerns on and a roadmap for RM chemistry to render the future development of RM-assisted high-efficiency and high-energy aqueous batteries.