Polyoxometalate Modified Separator for Performance Enhancement of Magnesium-Sulfur Batteries

The magnesium-sulfur (Mg-S) battery has attracted considerable attention as a candidate of post-lithium battery systems owing to its high volumetric energy density, safety, and cost effectiveness. However, the known shuttle effect of the soluble polysulfides during charge and discharge leads to a rapid capacity fade and hinders the realization of sulfur-based battery technology. Along with the approaches for cathode design and electrolyte formulation, functionalization of separators can be employed to suppress the polysulfide shuttle. In this study, a glass fiber separator coated with decavanadate-based polyoxometalate (POM) clusters/carbon composite is fabricated by electrospinning technique and its impacts on battery performance and suppression of polysulfide shuttling are investigated. Mg-S batteries with such coated separators and non-corrosive Mg[B(hfip)(4)](2) electrolyte show significantly enhanced reversible capacity and cycling stability. Functional modification of separator provides a promising approach for improving metal-sulfur batteries.

Automated summary

The magnesium-sulfur (Mg-S) battery is considered a promising candidate for post-lithium battery systems due to its high energy density, safety, and cost effectiveness. However, issues such as the shuttle effect of soluble polysulfides have hindered the realization of sulfur-based battery technology. This study investigates the use of a glass fiber separator coated with decavanadate-based polyoxometalate (POM) clusters/carbon composite to improve battery performance and suppress polysulfide shuttling, resulting in enhanced reversible capacity and cycling stability in Mg-S batteries.