Advanced aqueous Zn–halogen batteries with multi-electron transfer chemistry catalyzed by organic compounds: insights into mechanisms and prospects

Abstract

Rechargeable aqueous zinc–halogen batteries (ZHBs) are regarded as promising candidates for next-generation energy storage, due to their intrinsic safety, multi-electron redox chemistry, low redox potential, and high theoretical capacity. Nevertheless, their practical implementation is hindered by several critical challenges, such as sluggish reaction kinetics, an unexpected polyhalide shuttle effect, and poor electrode stability. In this review, we comprehensively summarize recent advances in halogen conversion chemistry facilitated by organic compounds, with a focus on their roles as cathode host materials and functional electrolyte additives in ZHBs. Results of the detailed analyses are provided of the electrochemical charge storage mechanisms and the selection criteria for organic compounds, emphasizing electrochemical stability, precise energy-level matching, dynamic interfacial adaptability, and the synergistic optimization of capacity and stability are provided. Furthermore, recent developments of representative organic compounds that enhance ZHB performance are summarized. For practical applications, current challenges and potential strategies to improve the electrochemical performance of ZHBs, specifically in terms of specific capacity, output voltage, cycle life, and rate capability, are proposed. Finally, perspectives on developing high-efficiency and high-energy ZHBs catalyzed by organic compounds with multi-electron transfer are discussed.