In Situ Constructing Ultrathin, Robust‐Flexible Polymeric Electrolytes with Rapid Interfacial Ion Transport in Lithium Metal Batteries

Abstract Safety of lithium metal batteries (LMBs) has been improved by using the solid‐state polymer electrolytes, but the performance of LMBs is still troubled by the poor interface of solid electrolytes/electrodes, leading to insufficient interfacial Li⁺ transport. Here, a novel ultrathin, robust‐flexible polymeric electrolyte is achieved by in situ polymerization of 1,3‐dioxolane in soft nanofibrous skeleton at room temperature without any extra initiator or plasticizer, leading to the electrolyte with rapid interfacial ion transport. This facilitated Li⁺ transportation is demonstrated by molecular dynamics simulation. Consequently, the as‐prepared electrolyte exhibits excellent cycling performance. The results indicate that the electrolyte works well in the LiFePO₄//Li cell at elevated temperature up to 90 °C, and further matches with the high‐voltage LiNi_0.8Mn_0.1Co_0.1O₂ cathode. This study provides an effective approach to constructing a practical polymeric electrolyte for fabrication of safe, high performance LMBs.