Atomic Synergy Catalysis Enables High-Performing Aqueous Zinc–Iodine Batteries

Abstract

Aqueous zinc-iodine batteries (AZIBs) are attractive energy storage systems with the features of low cost, sustainability, and efficient multielectron transfer mechanism. However, the I₂ cathodes face obstacles due to the sluggish redox kinetics and severe shuttle effect. Herein, the atomically dispersed selenium single atoms (Se SAs) are embedded in ZIF-8-derived nitrogen-doped carbon. This design not only triggers the rapid redox conversion of I₂ but also enhances the anchoring of polyiodides, thereby enabling the excellent lifespan and rate capability of the Zn-I₂ battery. Specifically, the Se SAs and N dopants on carbon achieve a rapid I₂/I^- couple conversion reaction via modulation of the conversion energy barrier, as revealed by in situ results coupled with density functional theory analysis. This work demonstrates the application of atomic synergy in facilitating the reversible conversion of iodine species and provides valuable insights into designing efficient I₂ hosts for next-generation AZIBs.