Constructing a lithiophilic and mixed conductive interphase layer in electrolyte with dual-anion solvation sheath for stable lithium metal anode

The application of lithium metal batteries (LMBs) is greatly inhibited by the uncontrollable growth of Li metal dendrites and the consequent safety hazards. Herein, we introduce AgSO3CF3 and LiNO3 into the electrolyte to form a stable mixed conductive interphase (MCI) layer on Li metal via in-situ surface reaction. Upon the surface reaction, ultrafine Ag nanoparticles uniformly formed on the Li surface that effectively seed dendrite-free lithium deposition. Besides, the SO3CF3- and NO3- anions in the solvation shell of Li+ can be reduced to produce an AgLiF-Li3N rich interface layer. The as-obtained uniform and robust layer renders a smooth Li morphology and fast interfacial kinetics. Therefore, Li||Li symmetrical cell exhibits a long lifespan over 2000 hours with an ultralow overpotential, and Li||LiFePO4 full cell maintains capacity retention of ~85% after 1100 cycles. The strategy proposed here opens a new avenue for addressing dendrite issues and makes the application of lithium metal batteries feasible.

Automated summary

This study introduces a stable mixed conductive interphase (MCI) layer on the surface of lithium metal through in-situ surface reaction, effectively inhibiting the growth of lithium metal dendrites and improving the interfacial kinetics. The electrochemical performance of lithium metal batteries is greatly enhanced, with a long lifespan and high capacity retention. This strategy provides a new approach to address dendrite issues and promotes the application of lithium metal batteries.