Core–shell zeolite imidazole framework-derived ZnSe@CoSe2/C heterostructure enabling robust polysulfide adsorption and rapid Li+ diffusion in high-rate and high-loading lithium–sulfur batteries

Due to their remarkable energy density of 2600 Wh kg−1, light weight, and low cost, lithium–sulfur (Li–S) batteries find promising uses in such emerging transportation areas as large commercial vehicles, high-altitude pseudosatellites, electric passenger aircraft, and etc. However, several challenges including the shuttle effect and sluggish sulfur redox reaction hinder their availability. Herein, a catalytic interlayer ([email protected]2/[email protected]) integrated with the [email protected]2/C heterostructure, derived from well-designed core–shell zeolite imidazole frameworks, is proposed for Li–S batteries. On one hand, the ZnSe surface regulates dissolved polysulfides around the interlayer owing to its strong adsorption on polysulfides. On the other hand, the conductive CoSe2 surface offers fast lithium-ion diffusion paths to accelerate the polysulfide conversion. Through their respective advantages, both ZnSe and CoSe2 could make a concerted effort to facilitate a smooth adsorption-diffusion-catalytic conversion process of polysulfides and guide the 3D growth of lithium sulfides around their heterointerfaces. Therefore, a high initial capacity of 1041.9 mAh g−1 at 0.5C and stable cycling performance with a high capacity retention of 70% over 550 cycles at 5C are achieved by the Li–S cells containing [email protected]2/[email protected] Under a high sulfur loading of 8.2 mg cm−2 with a sulfur content of 85%, the high areal capacity and impressive capacity retention could also be obtained in the [email protected]2/[email protected] cell. We believe that the heterostructure arming itself with robust polysulfide adsorption and rapid surface ion diffusion might also find potential uses for other rechargeable metal (Na, Mg, Al, Ca, etc.)–sulfur batteries.