Reclaiming Inactive Lithium with a Triiodide/Iodide Redox Couple for Practical Lithium Metal Batteries
Chengbin Jin, Xue‐Qiang Zhang, Ouwei Sheng, Shu‐Yu Sun, Li‐Peng Hou, Peng Shi, Bo‐Quan Li, Jia‐Qi Huang, Xinyong Tao, Qiang Zhang
Abstract
Abstract High‐energy‐density lithium (Li) metal batteries suffer from a short lifespan owing to apparently ceaseless inactive Li accumulation, which is accompanied by the consumption of electrolyte and active Li reservoir, seriously deteriorating the cyclability of batteries. Herein, a triiodide/iodide (I 3 − /I − ) redox couple initiated by stannic iodide (SnI 4 ) is demonstrated to reclaim inactive Li. The reduction of I 3 − converts inactive Li into soluble LiI, which then diffuses to the cathode side. The oxidation of LiI by the delithiated cathode transforms cathode into the lithiation state and regenerates I 3 − , reclaiming Li ion from inactive Li. The regenerated I 3 − engages the further redox reactions. Furthermore, the formation of Sn mitigates the corrosion of I 3 − on active Li reservoir sacrificially. In working Li | LiNi 0.5 Co 0.2 Mn 0.3 O 2 batteries, the accumulated inactive Li is significantly reclaimed by the reversible I 3 − /I − redox couple, improving the lifespan of batteries by twice. This work initiates a creative solution to reclaim inactive Li for prolonging the lifespan of practical Li metal batteries.