Safety-reinforced rechargeable Li-CO2 battery based on a composite solid state electrolyte

The rechargeable Li-CO 2 battery has been receiving significant attention owing to its merits of high energy density and the efficient utilization of CO 2 . However, the widely application is plagued by severe security risks, such as leakage, flammability and lithium dendrites growth due to the use of liquid organic electrolytes. Here, a composite solid state electrolyte consisting of polyethylene oxide (PEO) and 20 wt.% Li 7 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) was prepared and first introduced into Li-CO 2 battery to solve the problems. The composite solid state electrolyte exhibited high ionic conductivity (1.03 × 10 −1 S·cm −1 at 70 °C), wide electrochemical window (5 V vs. Li + /Li), good mechanical properties and excellent flexibility. Ultimately, the Li symmetric cell with PEO/LLZTO composite solid state electrolyte can operate 1,500 h at a current density of 0.1 mA·cm −2 . The assembled all-solid-state Li-CO 2 battery behaved a long cycle life of 70 cycles at a current density of 100 mA·g −1 with fixed capacity of 1,000 mAh·g −1 . Our work provides new perspective to develop rechargeable all-solid-state Li-CO 2 batteries.