Plasma and magnetron sputtering constructed dual-functional polysulfides barrier separator for high-performance lithium-sulfur batteries

In order to fundamentally suppress the shuttle effect, N 2 Plasma & Al 2 O 3 magnetron sputtered separators (Al 2 O 3 @ 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 Al 2 O 3 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 Al 2 O 3 film seals the shuttle channel of LiPSs to a certain extent. Chemically, N 2 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 Al 2 O 3 film, more stable chemical bonds are formed between Al 3+ 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.