Ni–CoSe2 heterojunction coated by N-doped carbon for modified separators of high-performance Li–sulfur batteries

Abstract

Functional separators modified by transition metal compounds have been proven to be effective in suppressing the shuttle effect of polysulfides and accelerating sluggish electrode dynamics in lithium–sulfur batteries (LSBs). However, the behaviors of heterojunctions composed of transition metals and their compounds in LSBs are still rarely studied. Herein, we report a novel Ni–CoSe₂ heterostructure coated with nitrogen-doped carbon. Compared to homogeneous cobalt diselenide, it exhibits much stronger adsorption and catalytic conversion abilities towards polysulfides. With the modified separators, the lithium–sulfur batteries exhibit significantly improved capacity retention and reduced polarization during cycling.