Promoting overall sulfur redox kinetics for Li–S batteries via interfacial synergy in a NiS–NiTe2 heterostructure-modified separator†

Abstract

Lithium–sulfur (Li–S) batteries have garnered significant attention as a promising alternative to conventional lithium-ion batteries due to their high theoretical energy density. However, challenges like the “shuttle effect” of sulfur dissolution, poor electrical conductivity, and the volume expansion during cycling have hindered their practical application. Herein, we successfully developed a highly efficient NiS–NiTe₂ heterostructure via a combination of solvothermal synthesis, sulfurization, and tellurization processes, which served as a functional layer on the traditional PP separator for high-performance Li–S batteries. The formed NiS–NiTe₂ heterostructure strengthened the chemical affinity for polysulfides, and accelerated sulfur redox conversion. The assembled Li–S cell with the NiS–NiTe₂ modified separator delivers a high specific capacity of 750 mA h g⁻¹ at 0.5C over 200 cycles, and high-rate performance of 480 mA h g⁻¹ at 2C. This work demonstrates that NiS–NiTe₂ enables durable sulfur electrochemistry and can impact future electrocatalytic designs related to various energy-storage applications. This work provides a novel approach for designing catalysts to facilitate the catalytic conversion of polysulfide intermediates.