A rechargeable all-solid-state Li–CO2 battery using a Li1.5Al0.5Ge1.5(PO4)3 ceramic electrolyte and nanoscale RuO2 catalyst

The fossil fuel crisis and global warming are becoming more and more severe in this century, while the exploration of human survival on Mars is being pushed forward steadily. Hence, it is meaningful to effectively utilize CO2, the main greenhouse gas and a major component of the Martian atmosphere. Due to their high capacity and ability to capture CO2, Li–CO2 batteries have received much attention. However, there are problems that still need to be solved relating to Li–CO2 batteries, including the instability of the electrolyte and the non-negligible polarization caused by the formation and decomposition of Li2CO3. To address these issues, an all-solid-state Li–CO2 battery, which uses RuO2 nanoparticles combined with single-walled carbon nanotubes (SWCNTs) as the cathode material and a sodium super ionic conductor (NASICON)-type ceramic solid electrolyte, Li1.5Al0.5Ge1.5(PO4)3 (LAGP), has been developed and it operates over a broad temperature range. Under a pure CO2 atmosphere, this well-designed battery shows a discharge capacity of 2499 mA h g−1 and a charge capacity of 2137 mA h g−1 in the first cycle at 60 °C, and stable cycling performance over 30 cycles under a capacity limitation of 500 mA h g−1 at a current density of 50 mA g−1. This result enhances the possibility of the utilization of the Li–CO2 battery in the future.