Electrically and thermally conductive Al2O3/C nanofiber membrane filled with organosilicon as a multifunctional integrated interlayer for lithium-sulfur batteries under lean-electrolyte and thermal gradient

Abstract

The development of lithium-sulfur (Li-S) batteries is dogged not only by severe limitations in cycling and rate performances arising from the shuttle effect of lithium polysulfides (LiPSs) but also severe degradation under harsh evaluation conditions of high sulfur loading, lean-electrolyte, and prominent thermal gradient. To achieve high performance and safety in Li-S batteries, a flexible and multifunctional integrated interlayer consisting of dual-functional alumina/carbon (Al2O3/C) nanofiber skeleton and organosilicon (OSi) filler is fabricated. Electrically and thermally conductive nanofibers are continuous and interlaced, enhancing the reutilization of LiPSs and the homogenization of temperature gradient through constructed dual-conductive networks. The interval-filled OSi helps in the diffusion of LiPSs and the absorption and retention of electrolytes, providing significant support to stabilize the Li-S batteries for long-term cycling. As a result, considerable enhancements in cycle stability and rate performance either under a high sulfur loading of ∼5.5 mg cm-2, low electrolyte/sulfur (E/S) rate of 4 μL mg-1, or artificial temperature gradients are achieved for a typical sulfur/carbon black cathode simply by incorporating multifunctional Al2O3/C@OSi interlayer. The new design and configuration of the interlayer may practically be used in high-energy applications since it can effectively address severe limitations of the current Li-S batteries.