CaF nanoparticles enabling LiF-dominated solid electrolyte interphase for dendrite-free and ultra-stable lithium metal batteries.

The uncontrollable growth of Li dendrites and severe interfacial parasitic reactions on the Li anode are the primary obstacles to the practical application of lithium (Li) metal batteries. Effective artificial solid electrolyte interphase is capable of regulating uniform Li deposition and isolateing Li from electrolyte, thereby eliminating parasitic reactions. Herein, we rationally design a uniform LiF-dominated solid electrolyte interphase through an in-situ reaction between CaF nanoparticles and the Li anode, which allows dendrite-free Li deposition and restrains interfacial deterioration. Accordingly, the protective Li electrode demonstrated exceptional stability, sustaining over 6000 h at a current density of 2 mA cm in symmetric cells and attaining over 1000 cycles with a low capacity decay rate of 0.015 % per cycle in coupling with LiFePO cathodes.