Freestanding oxidized poly(acrylonitrile-co-vinylpyrrolidone)/SnCl2 nanofibers as interlayer for Lithium-Sulfur batteries

Abstract

Lithium-Sulfur batteries are one of the most promising energy storage systems among the next generation batteries due to their high energy density and the natural abundance of sulfur. Nevertheless, some limitations hinder their implementation to the marketplace which are mostly linked to the shuttle effect resulting fast capacity lost and lithium poisoning by dissolved polysulfides. One of the possible solutions is the use of poly sulfide adsorptive interlayers between anode and cathode to inhibit the shuttle effect protecting lithium anode. In this work, oxidized poly(acrylonitrile-co-vinylpyrrolidone) nanofibers containing SnCl2 (oPANVP/SnCl2) are used as an interlayer to enhance the performance of Li-S cells. Unlike most of the current literature, the electrospun nanofiber mats are oxidized at 200 degrees C under air, but not further pyrolyzed to benefit from the functional groups and the partial formation of SnOx. 700 mAh g(-1) discharge capacity is obtained at C/5 after 100 cycles by using oPANVP/SnCl2, which is higher than the cells with oPANVP and without interlayer. The improved capacity is mostly associated with the complementary adsorption effect of SnCl2 particles, partially formed SnOx and functional groups of oPANVP. Polysulfide adsorption effect of SnCl2, SnOx, and nitrogen- and oxygen-rich functional groups of oPANVP is proven by X-Ray Photoelectron Spectroscopy.