SAFE-BIOBATT · Fire-safe and bio-based polymer electrolytes for new generation lithium-sulfur batteries

Low ionic conductivity as well as insufficient ability to suppress the shuttle effect and lithium dendrite growth has been a crucial problem constraining the development of polymer electrolytes, which further leads to the fact that the vast majority of solid-state lithium-sulfur batteries (SSLSBs) have to be operated above room temperature. Moreover, researchers have given much more emphasis on the energy density of batteries, while the fire-safety property is not given as much attention as the batterys performance. Therefore, facing these challenges, the overarching target of this ambitious yet achievable project (SAFE-BIOBATT) is to develop high energy density and fire-safe SSLSBs and to systematically investigate the electrochemical reaction mechanism based on these fabricated SSLSBs. In details, cross-linking biopolymer Carrageenan (Car), a promising and potential bio-based solid electrolyte with high ion conductivity at room temperature, with functionalized -cyclodextrin (CDP-Car) will be produced with the aim to not only facilitate the fire-safety of fabricated polymer-based electrolytes but also enhance the mechanical strength to suppress the lithium dendrite growth for their application in SSLSBs. The Car is not only fabricated as electrolyte but also developed as binder for sulfur electrode with the aim of effectively capturing lithium polysulfides. By introducing this bio-based fire-safe electrolyte in this project, the room-temperature polymer-based SSLSB can be achievable as breakthrough. Furthermore, LiN(CF3SO2)2 as a typical candidate salt will be employed in this bio-based electrolyte (CDP-Car-salt), expecting its effects in stabilizing the solid electrolyte interface and preventing the lithium dendrite. As compared to the current electrolytes and key components of the batteries which mainly rely on fossil-based sources, the strategy proposed here provides a safe and sustainable solution to the development of new generation fire-safe batteries.