Atomically dispersed Cu and Cr on N-doped hollow carbon nanocages for synergistic promotion of high-performance Li–CO2 batteries

Li–CO2 batteries have attracted considerable attention worldwide because of their high theoretical energy density and ability to capture CO2. However, the sluggish redox reaction kinetics, high overpotential, and insufficient durability of the cathodes remain a considerable challenge. In this study, we designed and prepared a Cu and Cr dual-atom co-doped carbon catalyst by chemically depositing both metal atoms on hollow bimodal porous carbon nanocages. For the batteries with our optimal sample as a cathode, a specific capacity of 23,928 mAh g−1, the lowest overpotential of only 0.8 V, and an ultralong cycle life of 338 cycles are achieved. Our developed sample exhibits superior characteristics over other existing cathode catalysts for Li–CO2 batteries. The synergetic effect between Cu and Cr was revealed by characterization and calculation, as well as its promotion mechanism. Meanwhile, the interconnected carbon nanocages provide excellent space for hosting discharge products while facilitating the access of CO2 and Li+ to the active sites. The encouraging performance of this work offers a new pathway for enhancing the performance of catalysts by introducing synergetic effects into the catalysts for Li–CO2 batteries.