The　rechargeable　Li-CO2　battery　has　attracted　much　attention　for　energy　storage　because　of　the　high　energy　density　and　efficient　utilization　of　greenhouse　gas.　However,　it＇s　still　suffered　by　low　safety　issue　of　liquid　electrolyte.　Herein,　a　composite　cathode　consisting　of　CNTs　and　polymer　electrolytes　was　fabricated　by　the　in-situ　polymerization　process　for　the　polymer　electrolyte-based　solid-state　Li-CO2　batteries.　With　the　good　dispersion　of　CNTs　and　polymer　electrolyte,　the　composite　cathode　is　covered　by　film-like　discharge　products　Li2CO3.　Furthermore,　the　Li-CO2　battery　shows　high　reversible　capacity　(similar　to　11,000　mAh　center　dot　g(-1)),　excellent　cycle　stability　(1000　mAh　center　dot　g(-1)　for　100　cycles)　under　low　charge　potential　(＜　4.5　V),　and　outstanding　rate　performances　at　room　temperature,　which　are　much　better　than　those　of　liquid　electrolyte-based　battery.　Therefore,　the　polymer　electrolyte-based　Li-CO2　battery　prepared　by　this　strategy　can　be　a　promising　candidate　to　meet　the　demands　of　high　safety　and　high-performance　energy　storage　devices.