In situ Triggered Rich‐LiF/Mg Multifunctional Passivation Layer for Modifying the Anode Interface of All‐Solid‐State Lithium Metal Batteries
Chengdeng Wang, Jun Wu, Jiamao Hao, Haofeng Shi, Lu Yang, Jiashuai Wang, Wang Zhi, Xiangrui Chen, Jinpeng Li, Yan Gao, Xiaoqin Yan, Yousong Gu
Abstract
Abstract Lithium (Li) is a promising anode material for all‐solid‐state Li metal batteries (ASSLMBs) due to its high energy density. However, the interface incompatibility of Li/solid electrolyte and uneven Li deposition induces the penetration of Li dendrites. Herein, a multifunctional rich‐LiF/Mg artificial solid electrolyte interphase (SEI) layer is constructed from a MgF 2 ‐PVDF‐HFP film to passivate the Li anode and achieve effective inhibition of Li dendrites. Notably, the triggered Li x Mg alloys rivet the Li 6 PS 5 Cl (LPSCl) electrolyte and Li anode together well, producing satisfactory interface contact and reducing overpotential. The mechanism of LiF and Li x Mg alloys to enhance the stability of the Li/LPSCl interface is further elucidated by density functional theory (DFT). Moreover, the synergistic interaction of LiF with high interfacial energy and Li x Mg alloys with low diffusion barrier promotes uniform deposition of Li during plating/stripping and structural stability. Therefore, the modified Li‐symmetric cell exhibits ultra‐high critical current density (2.0 mA cm −2 ) and considerable cyclic stability (more than 1000 h at 0.5 mA cm −2 ). Remarkably, NCM//LPSCl//3% MgF 2 ‐PVDF‐HFP@Li ASSLMBs exhibit considerable long‐term cycle stability (86.9% capacity retention after 100 cycles at 0.2 C). This work highlights the critical role of the intermediate passivating layer in mitigating side reactions and preventing Li penetration.