Rational Design of Co-NiSe2@N-Doped Carbon Hollow Structure for Enhanced Li-S Battery Performance

Lithium-sulfur (Li-S) batteries suffer from poor-cycle stability and low Coulombic efficiency, which are mainly caused by the intrinsic polysulfides shuttle, resulting from not only concentration gradient diffusion but also slow conversion kinetics of polysulfides. Herein, nitrogen-doped carbon-coated cobalt nickel selenide (Co-NiSe2@NC) with hollow structures is presented which can simultaneously accommodate the volume expansion of sulfur to maintain the integrity of the electrode, trap the polysulfides, and catalyze the conversion between lithium sulfide and lithium polysulfides to inhibit the polysulfides shuttle. When used to host 70 wt% sulfur, the resulted Co-NiSe2@NC-S composites electrode delivers a high initial discharge capacity of 930.4 mAh g(-1) at 0.5 C, and after 200 cycles, a reversible discharge capacity of 544.6 mAh g(-1) can still be maintained.