Ni Anchored to Hydrogen-Substituted Graphdiyne for Lithium Sulfide Cathodes in Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries are promising candidates for next-generation energy storage systems due to their high theoretical energy density and the low cost of sulfur. However, slow conversion kinetics between the insulating S and lithium sulfide (Li₂S) remains as a technical challenge. In this work, we report a catalyst featuring nickel (Ni) single atoms and clusters anchored to a porous hydrogen-substituted graphdiyne support (termed Ni@HGDY), which is incorporated in Li₂S cathodes. The rapidly synthesized catalyst was found to enhance ionic and electronic conductivity, decrease the reaction overpotential, and promote more complete conversion between Li₂S and sulfur. The addition of Ni@HGDY to commercial Li₂S powder enabled a capacity of over 516 mAh g_Li^-1 at 1 C for over 125 cycles, whereas the control Li₂S cathode managed to maintain just over 200 mAh g_Li^-1. These findings highlight the efficacy of Ni as a metal catalyst and demonstrate the promise of HGDY in energy storage devices.