Asymmetric N, O‐Coordinated Single Atomic Co Sites for Stable Lithium Metal Anodes

Lithium metal has been considered one of the most promising anodes for next‐generation rechargeable batteries, but its practical application is largely hindered by the uncontrollable dendrite growth and infinite volume change. Here, inspired by superior catalytic effects of single‐atom catalysts, carbon‐supported single atomic Co with asymmetric N, O‐coordination (Co‐N/O) is developed for Li metal battery. Experimental results and theoretical calculations indicate that single atomic Co atoms with asymmetric N, O‐coordination present enhanced binding ability toward Li in comparison with N‐coordinated atomic Co site and isolated O site, enabling uniform Li plating/stripping. Moreover, the asymmetric N, O‐coordination around Co atoms induces co‐activation effects, lowering the energy barriers toward Li+ to Li0 conversion and largely promoting the deposition kinetics. When used as a Li deposition host, the Co‐N/O achieves a high average coulombic efficiency of 98.6% at a current density of 1 mA cm−2 and a capacity of 2 mAh cm−2, long cycling life of 2000 h in symmetrical cells, and excellent rate performance (voltage hysteresis of 23 mV at 8 mA cm−2). This work provides a comprehensive understanding of single atomic metals with asymmetric heteroatom coordination in the design of Li metal anode.