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

Abstract

Lithium–sulfur\n(Li–S) batteries are promising candidates\nfor next-generation energy storage systems due to their high theoretical\nenergy density and the low cost of sulfur. However, slow conversion\nkinetics between the insulating S and lithium sulfide (Li₂S) remains as a technical challenge. In this work, we report a catalyst\nfeaturing nickel (Ni) single atoms and clusters anchored to a porous\nhydrogen-substituted graphdiyne support (termed Ni@HGDY), which is\nincorporated in Li₂S cathodes. The rapidly synthesized\ncatalyst was found to enhance ionic and electronic conductivity, decrease\nthe reaction overpotential, and promote more complete conversion between\nLi₂S and sulfur. The addition of Ni@HGDY to commercial\nLi₂S powder enabled a capacity of over 516 mAh g_Li₂S^–1 at 1 C for over 125 cycles, whereas\nthe control Li₂S cathode managed to maintain just over\n200 mAh g_Li₂S^–1. These findings\nhighlight the efficacy of Ni as a metal catalyst and demonstrate the\npromise of HGDY in energy storage devices.