Tuning CO₂ Electrocatalytic Reduction Path for High Performance of Li‐CO₂ Battery

Abstract The production of Li₂CO₃/C through CO₂ reduction reaction in nonaqueous systems is a complex four‐electron, multi‐step process, and the short existence time of intermediate monomers is not conducive to observation, which causes great difficulties in clarifying and regulating the CO₂ reduction path. Herein, ferrocene (Fc) as a functional additive into the electrolyte can stabilize the discharge intermediates and favor the occurrence of the two‐electron reaction path during CO₂RR, which leads to more stable operation of the Li‐CO₂ battery; with the assistance of Fc, the CO₂ reduction pathway in Li‐CO₂ battery is also clarified. Theoretical calculation analysis combined with experimental characterization observation confirms that Fc can shorten the CO₂ reduction distance through interaction with CO₂ and affecting the solvent environment around Li⁺, stabilize intermediate products to clarify the discharge path. The existence time of intermediates and discharge depth of the battery are key factors affecting the CO₂ reduction pathway. The Li₂C₂O₄ formed by CO₂ reduction through the 2‐electron pathway is more favorable for the reversible operation of the Li‐CO₂ battery than Li₂CO₃/C through the 4‐electron pathway. This work provides inspiration for clarifying the reaction mechanism and regulating the CO₂ reduction pathway to improve the electrochemical performance of Li‐CO₂ battery in the future.