Highly Conductive, Sulfonated, UV Cross Linked Separators for Li S Batteries
Metal (based on Li, Na, Mg, or Al) sulfur batteries are promising candidates for rechargeable electrochemical energy storage devices capable of high charge storage. However, the success of metal sulfur battery technology calls for solutions of fundamental problems associated with the inherently complex solution chemistry and interfacial reactivity of sulfur and polysulfide species in commonly used electrolytes. It is understood that the dissolution and shuttling of polysulfides induce rapid capacity degradation, poor cycling stability, and low efficiency of these cells. Herein, we report on the synthesis and transport properties of membranes containing sulfonate groups that are able to rectify transport of polysulfide species in liquid electrolytes. Composed of a cross linked polyethylene glycol (PEG) framework containing pendant SO32 groups, the membranes facilitate electrolyte wetting and Li+ ion transport, but are highly selective in preventing migration of negatively charged sulfur species (Sn2 dis.