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

Li–CO 2 batteries that integrate energy storage with CO 2 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 Li 2 CO 3 are major challenges hindering the practical implementation of Li–CO 2 batteries. To address these challenges, herein, a breakthrough Li–CO 2 battery leading to a soluble and easily-decomposed discharge product, C 2 O 4 2–, 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 C 2 O 4 2–, while simultaneously suppressing direct reduction of CO 2 to Li 2 CO 3 . The tough problems with Li–CO 2 batteries caused by solid products are effectively solved by production of soluble C 2 O 4 2–, which provides a promising solution for research on non-aqueous metal–air batteries.