A composite of Co-Mo2C/nitrogen-doped carbon nanotubes as efficient cathode catalyst for Li–CO2 batteries

Li–CO2 batteries have received increasing attention due to their high theoretical energy density. However, the insulating Li2CO3 formed in the discharge process is difficult to decompose in the charging process, resulting in high overpotentials, short cycle life, and poor rate capability. The rational design of cathode catalyst is crucial to form and decompose Li2CO3 during the discharge-charge cycles. Here, a Co-Mo2C/nitrogen-doped carbon nanotube composite has been achieved and introduced as the catalyst cathode for the Li–CO2 batteries. The bimetallic modified Co and Mo2C provide high catalytic activity during discharge and charge process, respectively. The assembled Li–CO2 batteries exhibit a low overpotential of 1.12 V at 100 mA g−1 with an extremely high discharge capacity of 18,001 mAh g−1, and provide a long-term stability of 120 cycles with a limited capacity of 500 mAh g−1. The bimetallic catalyst cathode design provides an efficient strategy to realize the high-performance Li–CO2 batteries.