Single-atom cadmium-N${}_4$ sites for rechargeable Li-CO${}_2$ batteries with high capacity and ultra-long lifetime

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. (© 2023 Wiley‐VCH GmbH)