POLYMER/CERAMIC HYBRID SEPARATORS FOR LITHIUM-SULFUR BATTERIES

Abstract

Lithium-sulfur (Li-S) is a promising candidate for next-generation batteries. There has been much effort in researching novel Li-S cathode materials to overcome inherent drawbacks, but limited attention to separator improvements, which can drastically affect ion diffusion and overall battery safety aspects. In this work, gas-assisted electrospinning is used to develop polymer/ceramic non-woven separators with polyimide (PI) and a polysilsesquioxane (PSSQ) ceramic. These separators are thermally stable well above temperatures seen in typical battery abuse conditions and retain their structural integrity even after being ignited. In Li-S cells, superior cycling performance is seen at high charge/discharge rates, owing to high ionic conductivity through the fibrous structure and favorable electrolyte interactions with PSSQ. To extend the previous work, a graphene interlayer was coated onto PI/PSSQ with an air-controlled electrospray method. This interlayer served as a physical barrier to hinder polysulfide shuttling and a “secondary cathode” to further improve battery rate capability performance.