Regulating Li deposition by constructing LiF-rich host for dendrite-free lithium metal anode

Abstract

Lithium (Li) metal anode is among the most promising anodes due to its high energy density. However, the long-standing issue of Li dendrites growth hinders the practical application of lithium metal batteries (LMBs) in portable electronics and electric vehicles. Engineering a dendrite-free Li metal anode is therefore critical for the development of long-life batteries. Here, an artificial LiF host with cuboid feature is constructed on Li metal surface by a facial one-step reaction of ammonium hydrogen difluoride (NH4HF2) with bare Li metal. During cycling, Li grows continuously from the bottom gaps to the top of the LiF host and finally cover the surface of the modified anode. Particularly, with the increasing of cycling capacity, the Li metal tend to deposit into scaly morphology which contributes to a dendrite-free anode. The as-obtained smooth Li anodes enabled stable cycling in working batteries with a low overpotential and a high Coulombic efficiency (CE) of 98.5% at the current density of 1 mA cm−2. This work provides a facile approach to prepare LiF-rich Li anode which paves the way to construct high-energy and safe LMBs.