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.
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