Single-atomic nickel supported on nitrogen-doped porous carbon to boost polysulfide conversion in lithium-sulfur batteries

Single-atomic catalysts consisting of atomically dispersed metal sites within nitrogen-doped carbon matrix (M SAC@NC) have emerged as high-performance electrocatalytic materials in Li-S batteries due to their maximum atom utilization, unique physicochemical properties, and superior catalytic activity. In the present work, a series of M SAC@NC (M = Ni, Co, Fe) with similar structural and physicochemical properties have been successfully prepared by the combination of physical adsorption and pyrolysis. The combination of the aberration-corrected high-angle annular dark-field scanning transmission electron microscopy and X-ray adsorption spectra indicates the successful formation of single-atomic metal sites. Moreover, the catalytic activity trend toward sulfur redox reaction is observed to be Ni SAC@NC > Co SAC@NC > Fe SAC@NC, and the Ni SAC@NC delivers the highest capacity of 1,280.6 mAh g⁻¹ and long-time stability at a decay rate of 0.07% per cycle for 800 cycles at 0.5 C, demonstrating excellent battery performance.