Zinc-Bromine Batteries Revisited: Unlocking Liquid-Phase Redox Chemistry for Next-Generation Energy Storage

Abstract

Aqueous zinc-bromine batteries (ZBBs) have attracted considerable interest as a viable solution for next-generation energy storage, owing to their high theoretical energy density, material abundance, and inherent safety. In contrast to conventional aqueous batteries constrained by sluggish ion diffusion through solid-state materials, ZBBs leverage the liquid-phase redox activity of bromine to achieve significantly higher power output, making them particularly attractive for grid-scale and stationary energy storage. However, persistent challenges such as zinc dendrite growth, bromine shuttle effects, and long-term cycling instability continue to limit their commercial viability. This review presents a comprehensive overview of the structural design, fundamental operating principles, and critical challenges of zinc-bromine batteries, with a particular emphasis on recent advances in electrode materials, electrolyte formulations, and separator development. Strategies aimed at addressing key limitations— such as stabilizing zinc deposition and suppressing bromine crossover — are systematically analyzed. By bridging the gap between laboratory-scale innovations and practical deployment, this review highlights the promise of zinc-bromine batteries as a high-performance, cost-effective, and sustainable energy storage technology, and outlines key future research directions.