A Reversible Six‐Electron Transfer Cathode for Advanced Aqueous Zinc Batteries

Abstract The electrochemical reactions for the storage of Zn 2+ while embracing more electron transfer is a foundation of the future high‐energy aqueous zinc batteries. Herein, we report a six‐electron transfer electrochemistry of nano‐sized TeO 2 /C (n‐TeO 2 /C) cathode by facilitating the reversible conversion of TeO 2 ↔Te and Te↔ZnTe. Benefitting from the integrated conductive nanostructure and the proton‐rich environment in providing optimized electrochemical kinetics (facilitated Zn 2+ uptake and high electronic conductivity) and feasible thermodynamic process (low Gibbs free energy change), the as‐prepared n‐TeO 2 /C with stable cycling performance exhibits a superior reversible capacity of over 800 mAh g −1 at 0.1 A g −1 . A precise understanding of the reaction mechanism via ex situ and in situ characterizations presents that the reversible six‐electron transfer reaction is proton‐dependent, and a proton generating and consuming mechanism of three‐phase conversion n‐TeO 2 /C in the weakly acidic electrolyte is thoroughly revealed.