Polymer electrolyte with composite cathode for solid‐state Li–CO 2 battery

The rechargeable Li–CO 2 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–CO 2 batteries. With the good dispersion of CNTs and polymer electrolyte, the composite cathode is covered by film‐like discharge products Li 2 CO 3 . Furthermore, the Li–CO 2 battery shows high reversible capacity (~ 11,000 mAh·g −1 ), excellent cycle stability (1000 mAh·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–CO 2 battery prepared by this strategy can be a promising candidate to meet the demands of high safety and high‐performance energy storage devices.