Sustained Release‐Driven Interface Engineering Enables Fast Charging Lithium Metal Batteries

Abstract LiNO 3 has attracted intensive attention as a promising electrolyte additive to regulate Li deposition behavior as it can form favorable Li 3 N, LiN x O y species to improve the interfacial stability. However, the inferior solubility in carbonate‐based electrolyte restricts its application in high‐voltage Li metal batteries. Herein, an artificial composite layer (referred to as PML) composed of LiNO 3 and PMMA is rationally designed on Li surface. The PML layer serves as a reservoir for LiNO 3 release gradually to the electrolyte during cycling, guaranteeing the stability of SEI layer for uniform Li deposition. The PMMA matrix not only links the nitrogen‐containing species for uniform ionic conductivity but also can be coordinated with Li for rapid Li ions migration, resulting in homogenous Li‐ion flux and dendrite‐free morphology. As a result, stable and dendrite‐free plating/stripping behaviors of Li metal anodes are achieved even at an ultrahigh current density of 20 mA cm −2 (>570 h) and large areal capacity of 10 mAh cm −2 (>1200 h). Moreover, the Li||LiFePO 4 full cell using PML‐Li anode undergoes stable cycling for 2000 cycles with high‐capacity retention of 94.8%. This facile strategy will widen the potential application of LiNO 3 in carbonate‐based electrolyte for practical LMBs.