Cesium Lead Chloride as an Artificial Solid Electrolyte Interphase for Enhanced Anode Protection in Lithium Metal Batteries

Lithium metal has the potential to further increase the energy density of lithium batteries. However, its inherent instability with conventional liquid electrolytes, which leads to low coulombic efficiency, has limited its practical application. In this study, we introduce a simple, low-cost drop-casting method to create an artificial solid electrolyte interphase (SEI) on the lithium surface using cesium lead chloride (CsPbCl₃). This inorganic protective coating enhances the interfacial stability between the lithium anode and the liquid electrolyte, effectively addressing common failure mechanisms. Symmetrical Li||Li cells with CsPbCl₃-Li demonstrate cycling stability for 600 h at a current density of 1 mA/cm² and a capacity of 1 mAh/cm². When paired with LiFePO₄ (LFP) cathodes (7.5 mg/cm²), CsPbCl₃-Li||LFP batteries retained 99.46% capacity at 1C for 250 cycles, outperforming uncoated lithium anodes. The coating strategy provides a promising solution for producing stable lithium metal and paves the way for developing rechargeable batteries with high energy density.