A Highly Reversible Lithium–Carbon Dioxide Battery Based on Soluble Oxalate

Li–CO2 batteries that integrate energy storage with CO2 fixation are expected to be a promising technology in the pursuit of carbon neutrality. However, cathode passivation and structural damage caused by the solid discharge product Li2CO3 are major challenges hindering the practical implementation of Li–CO2 batteries. To address these challenges, herein, a breakthrough Li–CO2 battery leading to a soluble and easily-decomposed discharge product, C2O42–, driven by regulating the solvation sheath of Li+, has been achieved by introducing the high-polarity dimethyl sulfoxide electrolyte. Experimental results and theoretical calculations show that the increased Li+ interaction and electrolyte molecule can induce the solution-phase formation of stabilized C2O42–, while simultaneously suppressing direct reduction of CO2 to Li2CO3. The tough problems with Li–CO2 batteries caused by solid products are effectively solved by production of soluble C2O42–, which provides a promising solution for research on non-aqueous metal–air batteries.