Engineering All-Solid Metal-Sulfur Batteries: Transport, Speciation, and Kinetics in Sulfur Copolymer Composite Cathodes

Metal-sulfur rechargeable batteries are a potentially cost-effective solution for replacement of Li-ion batteries for use in electric transportation. The energy density of lithium-sulfur and magnesium-sulfur batteries can exceed that of Li-ion, but only at low electrolyte-to-sulfur ratios. However, it is difficult to engineer sulfur batteries for high performance with low levels of liquid electrolyte.

In addition, elimination of volatile battery components to improve safety is preferred. In this project, the investigator will investigate solid-state metal-sulfur batteries based on copolymerized sulfur cathodes. The influence of the chemistry and morphology of the sulfur copolymer cathode on the ion transport, sulfur speciation, and reaction rates will be investigated.

The use of a solid copolymer interlayer to prevent the dissolution of sulfur species into the bulk polymer electrolyte will also be explored. This research will engage graduate and undergraduate Notre Dame students and visiting undergraduates from the Xavier University of Louisiana to promote the training and retention of researchers in the field of electrochemical engineering.

Additionally, the number, diversity, and training of the next generation of researchers in the chemical sciences and engineering will be enhanced by development of afterschool enrichment programming.

This fundamental engineering science research will be transformative for its contributions to the understanding of the effects of local environment on sulfur and poly(sulfide) electrochemical properties in the solid-state. Copolymerization of elemental sulfur and organic monomers will be leveraged to facilely tune the sulfur cathode environment, including the size and morphology of sulfur-rich and ion-rich domains, the interactions of ion-solvating components with poly(sulfide)s, and charge-transfer kinetics.

Spectroelectrochemical techniques will be used to investigate sulfur/(poly)sulfide speciation and reaction pathways. Separately, copolymer interlayers for active cation transport and polysulfide rejection in the solid-state will be investigated. Ion transport in both the cathode and interlayer nanostructured solid-state environments will be probed.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.