In Situ Catalytic Polymerization of a Highly Homogeneous PDOL Composite Electrolyte for Long‐Cycle High‐Voltage Solid‐State Lithium Batteries

High energy density solid-state lithium batteries require good ionic conductive solid electrolytes (SE) and stable matching with high-voltage electrode materials. Here, a highly homogeneous poly(1,3-dioxolane) composite solid electrolyte (CSE) membrane that can satisfy the above-mentioned requirements by in situ catalytic polymerization effect of yttria stabilized zirconia (YSZ) nanoparticles on the polymerization of 1,3-dioxolane (DOL), is reported. The well-dispersed YSZ nanoparticle catalyst leads to the polymerization conversion of DOL monomers up to 98.5%, which enlarges its electrochemical window exceeding 4.9 V. YSZ also significantly improves the room temperature ionic conductivity (2.75 × 10−4 S cm−1) and enhances the cycle life of lithium metal anode. Based on this CSE, the Li(Ni0.6Co0.2Mn0.2)O2 (NCM622)-based solid-state lithium battery shows a long cycle life over 800 cycles. This investigation encourages polymer SE toward practical high energy solid-state batteries.