High‐Performance Solid Lithium Metal Batteries Enabled by LiF/LiCl/LiIn Hybrid SEI via InCl3‐Driven In Situ Polymerization of 1,3‐Dioxolane

Abstract The use of poly(1,3‐dioxolane) (PDOL) electrolyte for lithium batteries has gained attention due to its high ionic conductivity, low cost, and potential for large‐scale applications. However, its compatibility with Li metal needs improvement to build a stable solid electrolyte interface (SEI) toward metallic Li anode for practical lithium batteries. To address this concern, this study utilized a simple InCl 3 ‐driven strategy for polymerizing DOL and building a stable LiF/LiCl/LiIn hybrid SEI, confirmed through X‐ray photoelectron spectroscopy (XPS) and cryogenic‐transmission electron microscopy (Cryo‐TEM). Furthermore, density functional theory (DFT) calculations and finite element simulation (FES) verify that the hybrid SEI exhibits not only excellent electron insulating properties but also fast transport properties of Li + . Moreover, the interfacial electric field shows an even potential distribution and larger Li + flux, resulting in uniform dendrite‐free Li deposition. The use of the LiF/LiCl/LiIn hybrid SEI in Li/Li symmetric batteries shows steady cycling for 2000 h, without experiencing a short circuit. The hybrid SEI also provided excellent rate performance and outstanding cycling stability in LiFePO 4 /Li batteries, with a high specific capacity of 123.5 mAh g −1 at 10 C rate. This study contributes to the design of high‐performance solid lithium metal batteries utilizing PDOL electrolytes.