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, carbonsupported 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.