Design of a La@Sn3o4/Ceo2 Heterostructure Based on Rare-Earth Element Modification to Enhance the Polysulfide Catalytic Conversion Rate of Lithium-Sulfur Batteries

Abstract

Currently, the obstacles to the feasibility of practical applications of lithium-sulfur batteries mainly come from the poor conductivity of the active substance sulfur, the slow kinetics of the polysulfide reaction, and the severe shuttle effect. Considering these issues, in this paper, a multicomponent La@Sn3O4/CeO2 heterostructure modified by rare-earth elements is constructed by a facile hydrothermal method to promote the catalytic conversion of LiPs and improve the cycling stability of the battery. In this heterostructure, the rare-earth La3+ modified substrate has a defect-rich and highly active interface that provides a large number of reaction sites, while the Sn3O4-CeO2 heterostructure interface has a strong interfacial electronic effect that accelerates the electron mobility and enhances the catalytic conversion efficiency to LiPs. In addition, the unique 4f5d electronic orbitals and variable valence states of the rare-earth elements effectively enhance the advantages of the heterostructures, exhibiting efficient sulfur utilization as well as good reaction kinetic rates, which are clearly confirmed by experimental and in situ Raman characterization. As a result, the La@Sn3O4/CeO2 heterostructure exhibits excellent initial discharge capacity (up to 1560 mAh·g-1 at 0.1 C) and good cycling stability (0.09% decay rate over 500 cycles at 1 C), proving that the combination of rare-earth elements and multi-component electrocatalysts has a promising future for the application of lithium-sulfur batteries.

Keywords: Lithium-sulfur batteries, Rare-earth elements, Multi-component electrocatalysts, Fast catalytic conversion, In-situ Raman