Regulating the Intermediate Process of Zinc–Bismuth Batteries by Iodide Ions

Abstract

Neutral aqueous electrolytes are more compatible with the anode of zinc metal batteries than alkaline electrolytes. Previous reports have shown that Zn||Bi2O3 batteries with mild electrolytes have not been able to function effectively, though Bi2O3 stands out as a promising cathode material with a low cost and potentially high capacity. Herein, iodide ions are introduced as a multifunctional electrolyte additive, allowing for a reversible multielectron conversion reaction of Bi(0) ↔ Bi­(III) in mild aqueous electrolyte. Iodide ions significantly alter the intermediate reaction steps, leading to a kinetically favorable mechanism through coordination with Bi3+ to continuously refresh and activate the interface. The resulting secondary neutral Zn||Bi2O3 battery delivers a high specific capacity (1960 mAh cm–3), exceptional rate performance, and remarkable cycling stability (1225 mAh cm–3 at 10 A g–1, retaining 85% after 1500 cycles) with the conversion efficiency close to 100% per cycle. This work provides an energetic perspective for reversible battery chemistry.

Rational Molecular Engineering via Electron Reconfiguration toward Robust Dual-Electrode/Electrolyte Interphases for High-Performance Lithium Metal Batteries

“…As a pragmatic and low-cost approach, additives are efficient to the integrated modification of electrolytes. − Based on the above discussion, the promising additives should simultaneously satisfy the following principles. (i) Strong interaction with Li ions can ensure adequate solubility and the regulation of solvation structure.…”