Reactivating the Dead Lithium by Redox Shuttle to Promote the Efficient Utilization of Lithium for Anode Free Lithium Metal Batteries

Abstract

AbstractAnode free lithium metal batteries (AFLMBs), as a kind of novel battery configuration with zero excess lithium, can improve the energy density to the limit compared with lithium metal batteries and effectively ensure the safety. However, the lifespan of AFLMBs is a tricky problem because there is no extra lithium source to compensate for the irreversible loss of active lithium, which is mainly caused by the continuous decomposition of electrolyte and the formation of dead lithium. Herein, a redox shuttle additive, which can be oxidized in the cathode and reduced in the electrolyte reversibly, is introduced to improve the lithium utilization and lifespan of AFLMBs by reactivating the dead lithium. During the charging process, the redox shuttle additive can be oxidized on the cathode surface and serve as electron acceptor toward dead lithium. The electrically isolated dead lithium in the electrolyte can be re‐activated into active lithium ions when captured by oxidized redox shuttle additive.As a result, electrolyte with redox shuttle achieves average higher coulombic efficiency of 99.13% than electrolyte without redox shuttle (97.71%). In addition, the AFLMB with redox shuttle exhibits improved cycling performance with extended lifespan.