Transition Metal d-band Center Tuning by Interfacial Engineering to Accelerate Polysulfides Conversion for Robust Lithium-Sulfur Batteries

Abstract

Although lithium-sulfur batteries (LSBs) promise high theoretical energy density and potential cost effectiveness, their applications are severely impeded by the shuttling and sluggish redox kinetics of lithium polysulfides (LiPSs). In this context, a Co₉ S₈ @MoS₂ heterostructure is sophisticatedly designed as an efficient catalytic host to boost the sulfur reduction reaction/evolution reaction (SRR/SER) kinetics and suppresses the LiPSs shuttling in LSBs. The results indicate that the electronic structure is manipulated in the Co₉ S₈ @MoS₂ heterostructure, where the built-in electric fields (BIEFs) within the heterointerfaces enable the sufficient adsorption sites to accelerate the ionic diffusion/charge transfer kinetics for LiPSs redox, thus enhancing the sulfur conversion. By tuning the electronic structure, the metal d-band of Co₉ S₈ @MoS₂ heterostructure plays an important role in adsorbing and catalyzing the conversion of LiPSs, thus promoting the reaction kinetics of the corresponding LSBs. This work unlocks the potential of heterostructures as promising catalysts to the design of high-energy and stabilized LSBs.

Keywords: Co 9S 8@MoS 2 heterostructures; d-band center tuning; lithium-sulfur batteries; sulfur reduction reaction/evolution reaction (SRR/SER) kinetics.