In-Situ Polymerization of 1,3-Dioxane Driven by a Bifunctional Initiator as Polymer Electrolytes for High Performance Solid-State Lithium Metal Batteries

Solid-state lithium metal batteries (SLMBs) are regarded as promising energy storage and conversion systems for the future due to their high energy density and safety, especially in the fields of electric vehicles and large-scale energy storage. However, the lithium metal anode easily generates irregular lithium dendrites during the charging and discharging process in SLMBs, which results in a short circuit and the loss of active lithium. These problems significantly reduce the Coulombic efficiency and cycle life of the SLMBs as well as seriously hinder practical progress. In this work, we reported the in situ preparation of poly(1,3-dioxolane) (PDOL) polymer electrolytes and Li–In alloy anode phases by introducing a bifunctional initiator (In(OTF)₃) into 1,3-dioxolane (DOL) electrolytes. The designed PDOL electrolytes not only exhibited an excellent wide electrochemical stability window (4.5 V vs Li/Li⁺), high ionic conductivity (0.51mS cm^–1), and high Li⁺ transfer number (0.61), but also inhibited lithium dendrites formation by forming Li–In alloy phases. Moreover, the assembled LFP|PDOL|Li batteries revealed excellent cycle stability and outstanding rate performance. In detail, the SLMBs presented a high specific capacity of 157 mAh g^–1 and a high capacity retention of 91.7% after 450 cycles at 0.2C. This work provides a strategy for designing in situ-polymerized electrolytes with the function of suppressing lithium dendrite growth and promotes the progress of practical application of SLMBs.