Plasma and magnetron sputtering constructed dual-functional polysulfides barrier separator for high-performance...

In order to fundamentally suppress the shuttle effect, N₂ Plasma & Al₂O₃ magnetron sputtered separators (Al₂O₃@N-PP) are proposed for lithium-sulfur batteries (LSBs). Such a dual-functional polysulfides (LiPSs) barrier separator greatly inhibits the shuttle effect from the perspective of physical and chemical interaction. Physically, the inherently electronegative amorphous Al₂O₃ first achieves the repulsion of LiPSs to the sulfur cathode through the electrostatic repulsive effect, effectively preventing a large amount of soluble LiPSs from accumulating at the separator. At the same time, the Al₂O₃ film seals the shuttle channel of LiPSs to a certain extent. Chemically, N₂ plasma-doped N heteroatoms form a lithium bond with Li⁺ in LiPSs to achieve the first step chemical adsorption and anchoring of LiPSs. When the LiPSs reaches the amorphous Al₂O₃ film, more stable chemical bonds are formed between Al³⁺ and S^2-, Li⁺ and O^2- to achieve more effective adsorption and anchoring of LiPSs. At 1C with a high sulfur loading up to 3-5 mg cm^-2 the LSB contributes a specific charge capacity of 717.4 mAh g^-1, with high retention rate up to 75.49 % after 450 cycles. The U-shaped electrolytic cell experiment and ultraviolet-visible spectrum experiment confirmed the LiPSs barrier function of the functional separator.