Thiosulfate‐Mediated Polysulfide Redox for Energetic Aqueous Battery

Abstract

Sulfur‐based aqueous batteries (SABs) are regarded as promising candidates for safe, low‐cost, and high‐energy storage. However, the sluggish redox kinetics of polysulfides pose a significant challenge to the practical performance of SABs. Herein, we report a unique redox regulation strategy that leverages thiosulfate‐mediated ligand‐chain interaction to accelerate the polysulfide redox process (S0/S2−). The S2O32− species in the electrolyte can induce the rapid reduction of polysulfide through a spontaneous chemical reaction with sulfur species, while facilitating the reversible oxidation of short‐chain sulfides. Moreover, the thiosulfate redox pair (S2O32−/S4O62−) within the K2S2O3 electrolyte contributes additional capacity at higher potential (E0 > 0 V vs SHE). Consequently, the elaborate SAB delivers an unprecedented K+ storage capacity of 2470 mAh gs−1, coupled with a long cycling life exceeding 1000 cycles. Remarkably, thiosulfate‐mediated SAB achieves an energy density of 616 Wh kgS+Zn−1, surpassing both organic K−S batteries and conventional aqueous battery systems. This work elucidates the mechanism underlying the thiosulfate‐mediated polysulfide redox process, thereby opening a pathway for the development of high‐energy aqueous batteries.