The　emerging　approach　of　in-situ　polymerization　of　solid　polymer　electrolytes　based　on　1,3-dioxolane　(DOL)　possesses　the　advantage　of　low　interfacial　impedance　and　relatively　high　Coulombic　efficiency.　However,　the　DOL　monomer　conversion　(C%)　under　Lewis　acid　catalysts　needs　to　be　further　improved,　besides　their　alloying　ability　with　lithium　metal　to　generate　protective　interfacial　layer　has　been　ignored.　Here,　the　above　two　aims　are　simultaneously　achieved　by　Indium　Trifluoride　(InF3)　catalyst.　It　is　demonstrated　that　the　highest　C%　is　up　to　94%　with　15　mg　of　InF3　in　the　1　mL　electrolyte　(1　M　LiTFSI/DOL).　The　optimized　ionic　conductivity　and　lithium-ion　transfer　number　are　8.9　×　10−5　S/cm　(30　°C)　and　0.42,　respectively.　The　stable　interface　between　poly-DOL　and　lithium　metal　anode　could　be　proved　by　the　stable　over-potential　(156mv,　900　h)　at　current　density　of　2.0　mA　cm−2.　X-ray　diffraction　results　confirm　the　presence　of　In　and　In–Li　alloy　peaks.　After　300　cycles　at　1C,　the　assembled　Li/PDI15/LiFePO4　cells　deliver　a　125.2mAh/g,　90%　capacity　retention　and　Coulombic　efficiency　of　99.75%,　respectively.　This　innovative　and　facile　strategy　of　dual　functional　InF3　on　the　in-situ　polymerization　of　DOL　and　solid　electrolyte　interphase　formation　provides　new　ideas　for　design　poly-DOL　based　solid　polymer　electrolytes.　©　2024　Elsevier　B.V.