CF4 Plasma‐Generated LiF‐Li2C2 Artificial Layers for Dendrite‐Free Lithium‐Metal Anodes

Abstract Lithium metal anodes have long been considered as “holy grail” in the field of energy storage batteries, but dendrite growth and large volume changes hinder their practical applications. Herein, a facile and eco‐friendly CF 4 plasma treatment is employed for the surface modification of Li anodes, and an artificial layer consisting of LiF and Li 2 C 2 is fabricated for the first time. Experimental results and theoretical calculations reveal that the high adsorption energy of LiF and low Li + diffusion barriers in Li 2 C 2 induce uniform nucleation and planar growth of Li, guaranteeing a stable and dendrite‐free Li structure during the repeated plating/stripping process of cycling. Symmetric cells using CF 4 plasma‐treated Li operate stably for more than 6500 h (at 2 mA cm −2 and 1 mAh cm −2 ) or 950 h (at 1 mA cm −2 and 10 mAh cm −2 ). When paired with a LiFePO 4 cathode, full batteries deliver a high reversible capacity of 136 mAh g −1 (at 1 C) with considerable cycling stability (97.2% capacity retention over 200 cycles) and rate performance (116 mAh g −1 up to 5 C). This powerful application of plasma technology toward novel LiF‐Li 2 C 2 artificial layers provide new routes for constructing environment‐friendly and high‐performance energy storage devices.