Recent advances of aqueous zinc-bromine batteries: electrochemistry, challenges and perspectives

Aqueous zinc-bromine batteries (AZBBs) gain considerable attention as a next-generation energy storage technology due to their high energy density, cost-effectiveness and intrinsic safety. Despite these advantages, challenges such as the polybromide ion shuttle effect, self-discharge, and zinc anode instability hinder their widespread applications. This review provides a comprehensive and systematic examination of recent advancements in AZBBs, beginning with an in-depth discussion of the fundamental electrochemical mechanisms underlying bromine redox reactions and the principal challenges inherent to these systems. Subsequently, it elucidates the most recent developments in the fabrication and optimization of electrode materials, electrolytes and separators, with particular emphasis on innovative strategies to ameliorate existing limitations. Furthermore, this article delineates the persisting challenges and prospective research directions for advancing AZBBs, including the design of advanced cathode materials, electrolyte optimization and device engineering. By addressing these critical aspects, this work endeavors to provide valuable insights and guidance for the development of high-performance AZBBs, paving the way for their practical implementation in large-scale energy storage applications.