Interrupting the Hydroxide Enrichment‐Induced Electrode Degradation Loop for Achieving Stable Aqueous Zn‐I <sub>2</sub> Batteries
Hanlin Ding, Zhenxin Lin, Xiaoting Lin, Jiachi Chen, Xiaoxin Huang, Minghui Ye, Zhipeng Wen, Yongchao Tang, Xiaoqing Liu, Yufei Zhang, Chengchao Li
Abstract
Abstract Severe adverse reactions, including hydrogen evolution reaction (HER) and polyiodide shuttle, lead to short lifetimes of rechargeable aqueous zinc‐iodine (Zn‐I 2 ) batteries and have aroused widespread attention. However, few studies have specifically investigated the impact of hydroxide ion (OH − ) disturbance generated by side reactions on the Zn anode and I 2 cathode in aqueous electrolytes. Herein, a facile electrolyte additive strategy was introduced to break the OH − enrichment‐induced bidirectional electrode degradation loop toward achieving stable Zn‐I 2 cells. Particularly, the bidirectional additive restricts the crossover of OH − , suppressing the iodine hydrolysis reaction‐induced polyiodide formation and capturing polyiodides to prevent shuttling. It also preferentially interacts with Zn, simultaneously reconstructing the solvation shell and promoting the formation of a hybrid ZnS‐rich solid electrolyte interface (SEI) to improve Zn kinetics and inhibit HER. Therefore, a stable cycling of Zn//Zn cells can be sustained for 1700 and 400 h in acidic and alkaline electrolytes, respectively. Impressively, the Zn‐I 2 cell achieved a cycle life of 9000 cycles at a high mass loading of 12 mg cm −2 . The concept of bi‐directional synergetic regulation for accounting for the aqueous environment is expected to provide a new approach for highly stable aqueous Zn‐I 2 batteries.