Decreasing the Overpotential of Aprotic Li‐CO2 Batteries with the In‐Plane Alloy Structure in Ultrathin 2D Ru‐Based Nanosheets

Abstract The aprotic Li‐CO 2 battery is emerging as a promising energy storage technology with the capability of CO 2 fixation and conversion. However, its practical applications are still impeded by the large overpotential. Herein, the general synthesis of a series of ultrathin 2D Ru‐M (M = Co, Ni, and Cu) nanosheets by a facile one‐pot solvothermal method is reported. As a proof‐of‐concept application, the representative RuCo nanosheets are used as the cathode catalysts for Li‐CO 2 batteries, which demonstrate a low charge voltage of 3.74 V, a small overpotential of 0.94 V, and hence a high energy efficiency of 75%. Ex/in situ studies and density functional theory calculations reveal that the excellent catalytic performance of RuCo nanosheets originates from the enhanced adsorption toward Li and CO 2 during discharge as well as the elevated electron interaction with Li 2 CO 3 during charge by the in‐plane RuCo alloy structure. This work indicates the feasibility of boosting the electrochemical performance of Li‐CO 2 batteries by in‐plane metal alloy sites of ultrathin 2D alloy nanomaterials.