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, due 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 ZBBs, with a particular emphasis on recent advances in electrode materials and electrolyte formulations. 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 ZBBs as a high-performance, cost-effective, and sustainable energy storage technology, and outlines key future research directions.