A Self‐Reconfigured, Dual‐Layered Artificial Interphase Toward High‐Current‐Density Quasi‐Solid‐State Lithium Metal Batteries

The uncontrollable dendrite growth and unstable solid electrolyte interphase have long plagued the practical application of Li metal batteries. Herein, a dual-layered artificial interphase LiF/LiBO-Ag is demonstrated that is simultaneously reconfigured via an electrochemical process to stabilize the lithium anode. This dual-layered interphase consists of a heterogeneous LiF/LiBO glassy top layer with ultrafast Li-ion conductivity and lithiophilic Li-Ag alloy bottom layer, which synergistically regulates the dendrite-free Li deposition, even at high current densities. As a result, Li||Li symmetric cells with LiF/LiBO-Ag interphase achieve an ultralong lifespan (4500 h) at an ultrahigh current density and area capacity (20 mA cm-2 , 20 mAh cm-2 ). LiF/LiBO-Ag@Li anodes are successfully applied in quasi-solid-state batteries, showing excellent cycling performances in symmetric cells (8 mA cm-2 , 8 mAh cm-2 , 5000 h) and full cells. Furthermore, a practical quasi-solid-state pouch cell coupling with a high-nickel cathode exhibits stable cycling with a capacity retention of over 91% after 60 cycles at 0.5 C, which is comparable or even better than that in liquid-state pouch cells. Additionally, a high-energy-density quasi-solid-state pouch cell (10.75 Ah, 448.7 Wh kg-1 ) is successfully accomplished. This well-orchestrated interphase design provides new guidance in engineering highly stable interphase toward practical high-energy-density lithium metal batteries.