Single-Atom Cadmium-N-4 Sites for Rechargeable Li-CO2 Batteries with High Capacity and Ultra-Long Lifetime

Abstract

The rechargeable Li-CO2 battery shows great potential in civil, military, and aerospace fields due to its high theoretical energy density and CO2 capture capability. To facilitate the practical application of Li-CO2 battery, the design of efficient, low-cost, and robust non-noble metal cathodes to boost CO2 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-CO2 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 Li2CO3 formation and decomposition reactions during the respective discharge and recharge process, evidencing the high catalytic activity of single Cd sites. This work provides a simple and effective avenue for developing highly active and stable single-atom non-precious metal cathode catalysts for advanced Li-CO2 batteries.