In-situ formation of LiF-rich solid-electrolyte interphases on 3D lithiophilic skeleton for stable lithium metal anode

Abstract

Lithium (Li) metal with high theoretical capacity is considered as one of the important anode materials for the next-generation high-energy density batteries. However, the further commercial application of Li metal anode is hindered by the severe growth of uncontrollable Li dendrites and the destructive regrowth of unstable solid-electrolyte interphases (SEI) layer. Herein, through the combination of thin film deposition coating and in-situ fluoridation, a composite layer with the lithophilic layer and the LiF-rich SEI layer is realized on Cu foam current collector. Specifically, the lithiophilic layer on the surface of current collector helps to regulate the homogeneous Li plating/stripping behavior. More importantly, after in-situ fluoridation, the LiF-rich layer as a robustly artificial SEI can be in-situ generated on the surface of current collector during initial activation process to stabilize cycling performance with dendrite-free. Consequently, the well-designed 3D current collector enables dendrite-free Li deposition behavior, high average coulombic efficiency (97.74% for 500 cycles at 1 mA cm−2 & 1 mAh cm−2), stable Li plating/stripping behavior (over 2400 h with an ultra-low overpotential of 10 mV at 2 mA cm−2 & 2 mAh cm−2) and remarkable cycling stability/rate performance in both coin-type and pouch full cells. These encouraging results provide new insights into the design of high-performance Li metal anodes for the development of Li metal batteries.