In-Situ-Polymerized 1,3-Dioxolane Solid-State Electrolyte with Space-Confined Plasticizers for High-Voltage and Robust Li/LiCoO₂ Batteries

In-situ-polymerized solid-state electrolytes can significantlyimprove the interfacial compatibility of Li metal batteries. Typically,in-situ-polymerized 1,3-dioxolane electrolyte (PDOL) exhibits goodcompatibility with Li metal. However, it still suffers from the narrowelectrochemical window (4.1 V), limiting the application of high-voltagecathodes. Herein, a novel modified PDOL (PDOL-F/S) electrolyte withan expanded electrochemical window of 4.43 V and a considerable ionicconductivity of 1.95 x 10(-4) S cm(-1) is developed by introducing high-voltage stable plasticizers (fluoroethylenecarbonate and succinonitrile) to its polymer network. The space-confinedplasticizers are beneficial to construct a high-quality cathode-electrolyteinterphase, hindering the decomposition of lithium salts and polymersin electrolytes at high voltage. The as-assembled Li|PDOL-F/S|LiCoO2 battery delivers superior cycling stability (capacity retentionof 80% after 400 cycles) at 4.3 V, superior to that of pristine PDOL(3% after 120 cycles). This work provides new insights into the designand application of high-voltage solid-state lithium metal batteriesby in situ polymerization.