Separator Engineering Regulating Reversible Li Electrodeposition Enabled by Lithiophilic Polyimide@Ag Coating Layer for Dendrite‐Free Lithium Metal Batteries

Abstract Heterogeneity Li deposition predominantly induce the growth of Li dendrite, which hinders the practical application of lithium metal batteries (LMBs). Previous researches have mainly focused on the modification of lithium anode, but lithium is sensitive to water and oxygen, which consequently limits its industrialization process. Herein, a novel polyimide@Ag coated polyethylene separator ((PI@Ag)/PE) strategy is reported to inhibit Li dendrites growth. It has been clarified that the lithiophilic PI@Ag microspheres can greatly reduce the nucleation barrier of Li electrodeposition. Consequently, the Li//Li cells with this separator exhibit stable and dendrite‐free Li ⁺ plating/stripping over 2000 h at 1 mAh cm ⁻² and 500 h at 5 mAh cm ⁻² . Moreover, the LiFePO ₄ //Li cells and Ni _0.8 Co _0.1 Mn _0.1 //Li cells exhibit excellent cycling performance and capacity retention after 400 cycles at 1C. Multiple characterization analyses have proved that the lithiophilic PI@Ag layer can significantly inhibit the growth of Li dendrites and help to construct a stable solid electrolyte interfacial (SEI) layer. The above results manifest that the present strategy provides a simple and generalized achievable method to solve the lithium dendrite problem, demonstrating bright engineering application value and broad prospect.