(373a) Understanding the Interplay of Polymer Chemistry and Morphology on Polysulfide Transport in Metal-Sulfur Rechargeable Batteries

If the wide-scale adaptation of renewable energy is to be successful and implemented quickly, a similarly targeted approach to developing next-generation energy storage is also necessary. Renewable energy generated in times of excess needs to be stored for later use when the wind is not blowing or the skies are cloudy. Of the many promising means for energy storage, metal-sulfur based rechargeable batteries hold particular interest due to their high theoretical capacities, the widespread abundance of active material, and compatibility of many alkali or alkaline earth metals with sulfur redox chemistry. One of the major challenges facing metal-sulfur batteries is the phenomenon known as the polysulfide shuttle, wherein sulfur and sulfur intermediates known as polysulfides do not remain housed in the cell cathode. The polysulfide shuttle results in loss of active material and parasitic side reactions at the anode, leading to metal-sulfur cells having quick capacity fade and short life-spans. While this challenge has been approached from many directions, by far one of the most under-explored angles is the use of active polymers to control the transport behavior of sulfur and polysulfides.

Presented here is work on understanding the influence of crosslinked polymer chemistry and various scales of morphology on polymer-sulfur interactions. With careful attention to these properties, we have demonstrated polymers that interrupt the polysulfide shuttle in magnesium-sulfur batteries and identified a relationship between polymer dielectric constant and polysulfide absorption. From investigating an inherent failure mechanism for condensed acrylate-based polymers used in lithium-sulfur cells, we have proposed additional design rules for future polymeric materials that seek to alter sulfur transport. Using materials guided by these newly proposed design rules, specifically making use of intentional morphology, we present early results of controlling sulfur and polysulfide transport effectively in lithium- and magnesium-sulfur batteries with polymers.