High‐Voltage Stimulation Effect on Lithium Deposition for 4.6 V‐Class Lithium Metal Batteries

Abstract Rechargeable Li‐ion batteries (LIBs) are ubiquitous in present society and play an important role in consumer electronics and electric vehicles. Increasing LIBs’ energy density is therefore becoming a crucial research challenge with great implications. Li metal is a high‐specific‐capacity anode, which suffers from uneven Li deposition, “dead” Li formation, dendrite growth, and the resulting severe capacity fading. Here, a strategy to enable a tremendous improvement for LiCoO 2 ‐based Li metal batteries (Li||LCO) is described and experimentally demonstrated. By simply adjusting the charge cut‐off voltage from 4.1 to 4.6 V, a high‐voltage stimulation effect (HvSE) is demonstrated, which offers a uniform, dense, and crack‐free Li deposition. As a result, the Li||LCO cell delivers a high energy density (ED) of 891 Wh kg ‐LCO −1 and a high capacity of 217 mAh g −1 can be maintained for more than 69 cycles. In contrast, the Li||LCO cell with the lower charge cut‐off voltage of 4.1 V only delivers a low ED (458 Wh kg ‐LCO −1 ), specific capacity (117 mAh g −1 ), and “capacity diving” occurs after only 35 cycles. This HvSE is also applied to run pouch cells, which generate greater than 20% capacity and cycling performance improvement with the higher charge cut‐off voltage.