Materials Science & Engineering PhD Student Lunch and Seminar

One of the students in the Materials Science and Engineering PhD program will provide an update on their graduate research. Students in the program and students interested in learning more are welcome!

To RSVP, contact Heidi Deethardt for the meeting invitation.


Piyush Deshpande, Department of Chemical and Biomolecular Engineering

Title: Engineering All-Solid Metal-Sulfur Batteries with Polymer Electrolytes

Abstract: High energy density and high-performance metal-sulfur batteries are sought after as a potential improvement on the current Li-ion battery technology. The high energy density that would be achieved from metal-sulfur batteries can be used to power large vehicles, such as semi-trucks and airplanes, aiding in the global movement towards more sustainable energy. The use of sulfur as a cathode material in these devised batteries is beneficial due to the abundance of sulfur as well as its low cost. A solid polymer electrolyte will be used for the battery in this study as opposed to the standard liquid electrolyte. This is a safety benefit since the volatile, flammable liquid components would be eliminated from the batteries. Liquid electrolyte batteries are also more susceptible to the polysulfide shuttle effect where reaction intermediate metal sulfides (MxSy) dissolve into the electrolyte, “shuttle” to the anode, and then react with it, thus diminishing the electrochemical capacity of the cell. In this work, we investigate lithium-sulfur batteries based on solid polymer electrolytes and sulfur copolymer cathodes with built-in ion transport channels. We report on the synthesis of the crosslinked sulfur copolymer as well as the characterization of the bulk material properties of the copolymer and the overall composite cathode. These characterizations include differential scanning calorimetry for determining the glass transition temperature to examine the existence of unincorporated elemental sulfur in the synthesized copolymer, dielectric / impedance spectroscopy for characterizing ionic conductivity and Li+ transference in this copolymer system, absorption spectroscopy for evaluating the absorption of the lithium polysulfides into the polar region of the polymers, and Raman spectroscopy during cycling of the battery for gaining information on the charge / discharge reaction pathways with sulfur and polysulfide speciation along with the ionic interactions that impact cation transport in the solid state.