Ultrathin RuRh Alloy Nanosheets Enable High-Performance Lithium-CO2 Battery

The aprotic Li-CO2 battery with high energy density is an attractive energy-storage technology. However, its development is largely impeded by the sluggish kinetics of CO2 reduction and evolution reactions. Here, we demonstrate a class of ultrathin triangular RuRh alloy nanosheets as an exceptionally active catalyst for greatly accelerating the kinetics of CO2 reduction and evolution reactions and achieving a high-performance Li-CO2 battery. The RuRh alloy nanosheets-based battery can achieve the lowest voltage gap of 1.35 V during the charge-discharge process and stably cycle for 180 cycles with a cutoff capacity of 1,000 mAh g−1 at 1,000 mA g−1. Density functional theory calculations demonstrate the pivotal roles of Rh introduction in RuRh alloy nanosheets, which evidently activate the electron-transfer ability of surface Ru and balance the CO2 binding near Ru sites. We find that the d-d correlation between Rh and Ru contributes to the energetically favorable cycle of the Li-CO2 battery.