The development of new rechargeable battery systems employing novel chemistries is imperative to meet the increasing energy storage demands of electric transportation and to support the increase of electricity generation via intermittent renewable resources. Of particular interest is the development of battery systems employing abundant materials and with increased energy density. The magnesium-sulfur (Mg-S) rechargeable battery could potential excel along the metrics of both material resource availability and system energy density, but the Mg-S system is plagued by many challenges. We show that self-discharge is a serious problem in Mg-S batteries based on a wide variety of demonstrated electrolytes. Furthermore, both self-discharge and purposeful discharge result in the formation of magnesium polysulfides in the electrolyte that undesirably precipitate in various locations of the cell. The detailed composition of the electrolyte (chemical identity of solvents, salts, and concentration thereof) influence the speciation of the polysulfides. Finally, we show that various polymers have varying interactions with polysulfides, influencing their stability.

Magnesium polysulfides in Mg-S batteries: Solubility and interactions

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.