Single‐Atom Cadmium‐N4 Sites for Rechargeable Li–CO2 Batteries with High Capacity and Ultra‐Long Lifetime

Abstract The rechargeable Li–CO 2 battery shows great potential in civil, military, and aerospace fields due to its high theoretical energy density and CO 2 capture capability. To facilitate the practical application of Li–CO 2 battery, the design of efficient, low‐cost, and robust non‐noble metal cathodes to boost CO 2 reduction/evolution kinetics is highly desirable yet remains a challenge. Herein, single‐atom cadmium is reported with a Cd‐N 4 coordination structure enable rapid kinetics of both the discharge and recharge process when employed as a cathode catalyst, and thus facilitates exceptional rate performance in a Li–CO 2 battery, even up to 10 A g −1 , and remains stable at a high current density (100 A g −1 ). An unprecedented discharge capacity of 160045 mAh g −1 is attained at 500 mA g −1 . Excellent cycling stability is maintained for 1685 and 669 cycles at 1 A g −1 and capacities of 0.5 and 1 Ah g −1 , respectively. Density functional theory calculations reveal low energy barriers for both Li 2 CO 3 formation and decomposition reactions during the respective discharge and recharge process, evidencing the high catalytic activity of single Cd sites. This study provides a simple and effective avenue for developing highly active and stable single‐atom non‐precious metal cathode catalysts for advanced Li–CO 2 batteries.