Highly stable and dendrite-free lithium metal batteries enabled by a novel artificial interphase layer

The practical application of lithium metal batteries (LMBs) has been significantly hindered by two critical challenges: inferior cycling stability and potential safety risks arising from uncontrollable lithium dendrite growth. Herein, a multifunctional hybrid protection layer consisting of Li₃Bi/LiF was in-situ constructed by spontaneous reduction reaction between Li and BiF₃. In this configuration, the highly lithiophilic Li₃Bi component serves as nucleation seeds to decrease the nucleation barrier and guide a uniform Li deposition. Meanwhile, LiF with high ionic conductivity promotes Li⁺ diffusion kinetics and homogenous Li⁺ flux during Li plating/stripping. Benefiting from these merits, the Li∥Li symmetric cell with BiF₃-Li exhibits excellent Li plating/stripping behaviors over 2500 h at 3 mA cm⁻² for 3 mAh cm⁻² with a low voltage hysteresis of 60 mV. Furthermore, the BiF₃-Li∥LiFePO₄ full cell demonstrates a remarkable capacity retention of 73% after 1700 cycles at 1 C. This work not only provides a facile strategy for developing multifunctional artificial inter-layers but also offers valuable insights for the design and fabrication of high-performance LMBs. (Figure presented.)