Facile one-pot synthesis of Co3Mo3N-loaded inside hierarchical porous bead-on-string as cathode host material for high-performance lithium-sulfur batteries

Abstract

• Develop an upgraded method for manufacturing bead-on-string structures. • A unique bead-on-string host material with a hierarchically porous structure inside. • The host material significantly enhances the stability of the sulfur cathode. • The battery performance is superior to commercial batteries under harsh conditions. • In-depth insight into the catalytic mechanism of Co 3 Mo 3 N on S conversion by DFT . A critical factor impeding the development of lithium-sulfur batteries is the deleterious shuttle effect. To address the issue, we devise a facile electrospinning approach to integrate catalysts and hierarchically porous structures into bead-on-string carbon host material as the host material. Compared to the traditional preparation of hierarchical porous structures, the upgraded electrospinning eliminates the need for etching templates, providing a larger specific surface area (333.39 m 2 g −1 ) and tremendous potential for large-scale production. The cathode utilizing bead-on-string Co 3 Mo 3 N as host material exhibits a remarkable capacity of 1257 mAh g −1 at 0.2 C and maintains a capacity retention rate of 90 % after 100 cycles. Even at 4.0 C, the capacity remains at 648 mAh g −1 with minimal capacity loss. Under harsh conditions (including high sulfur loading, high areal loading, and lean electrolyte), the composite cathode consistently delivers a capacity of 8 mAh cm −2 . Simultaneously, systematic electrochemical testing, in-situ assessments, and DFT calculations unveil the dual-metal synergistic effects of Co 3 Mo 3 N in suppressing the shuttle effect and catalyzing the conversion of lithium polysulfides. Co 3 Mo 3 N provides chemical adsorption to significantly promote the reaction kinetics of polysulfides. This work establishes a neoteric technique and a theoretical strategy for exploring the catalytic efficacy of dual-metal nitrides for Li-S batteries.