A Li₃Bi/LiF interfacial layer enabling highly stable lithium metal anode

Lithium metal anode is considered the alternative to graphite anode due to its ultra-high theoretical capacity of 3860 mAh center dot g(-1). However, serious Li dendrite growth and drastic electrolyte side reactions restrain the commercial application of Li metal anode. In this work, a Li3Bi/LiF interfacial layer is constructed on the surface of the Li metal anode by a spontaneous substitution reaction. The composite interfacial layer possesses excellent ionic conductivity, high mechanical strength, and great electrolyte wettability, which ensures fast Li-ion transfer and uniform Li deposition of the Li3Bi/LiF@Li anode. Impressively, the Li3Bi/LiF@Li symmetric cell provides a cycle life of more than 400 h with only 73 mV voltage polarization at 10 mA center dot cm(-2). By pairing with commercial NCM622 cathode, the Li3Bi/LiF@Li full cell exhibits a long cycle at a rate of 2 C.