Ultrafast Electrochemical Growth of Lithiophilic Nano‐Flake Arrays for Stable Lithium Metal Anode
Haorui Shen, Fulai Qi, Hucheng Li, Pei Tang, Xuning Gao, Shan Yang, Zichen Hu, Zhuangnan Li, Jun Tan, Shuo Bai, Feng Li
Abstract
Abstract Lithium dendrites caused by nonuniform Li + flux leads to the capacity fade and short‐circuit hazard of lithium metal batteries. The solid electrolyte interface (SEI) is critical to the uniformity of Li + flux. Here, an ultrafast preparation of uniform and vertical Cu 7 S 4 nano‐flake arrays (Cu 7 S 4 NFAs) on the Cu substrate is reported. These arrays can largely improve the lithiophilicity of the anode and form Li 2 S‐enriched SEI due to the electrochemical reduction of Cu 7 S 4 NFAs with lithium. A further statistical analysis suggests that the SEI, with a higher content of Li 2 S, is more effective to inhibit the formation of lithium dendrites and yields less dead lithium. A quite stable coulombic efficiency of 98.6% can be maintained for 400 cycles at 1 mA cm –2 . Furthermore, at negative to positive electrode capacity ratio of 1.5 (N/P = 1.5), the full battery of Li@Cu 7 S 4 NFAs||S shows 83% capacity retention after 100 cycles at 1 C, much higher than that of Li@Cu||S (33%). The findings demonstrate that high Li 2 S content in the SEI is crucial for the dendrite inhibition to achieve better electrochemical performance.