DISSERTATION PROPOSAL DEFENSE

by

Rebecca Glaser

Title: Tuning Active Material Microstructure and Electrolyte Composition for Enhanced Performance of High-Loading Cathodes For Lithium-Sulfur Batteries

Thursday, August 15, 2019

10:00 AM
in MRDC 3515

Committee Members:

Prof. Gleb Yushin, Advisor, MSE

Prof. Jud Ready, GTRI

Mohan Sanghadasa, Ph.D., US Army CCDC Aviation and Missile Center, Redstone Arsenal, AL

Prof. Preet Singh, MSE

Prof. Meilin Liu, MSE

Abstract:

Lithium sulfur (Li-S) batteries have the potential to revolutionize rechargeable energy storage technologies because they promise high theoretical gravimetric capacity combined with lower cost and lower toxicity. Fabrication of high areal loading (thicker) S cathodes is particularly important for maximizing Li-S cell energy storage characteristics because the weight and volume of inactive cell components (metal current collectors and separator membranes) undesirably contribute a significant portion of that for the otherwise lightweight Li-S cells. Unfortunately, making high-performance energy-dense Li-S cells with thick and dense electrodes is extremely challenging. Here I aim to systematically investigate two strategies for enhancing performance of high-loading S cathodes and uncover fundamental mechanisms that govern the complex structure/chemistry – electrochemical performance relationships. First, I will explore the incorporation of layered lithium metal oxides into the design of S-based cathodes. The use of lithium metal oxides has largely not been explored, except in a few earlier studies by our group. I aim to investigate different strategies for the formation of core-shell Li2S/Li-M-O particles, where M is the selected metal or metal combinations. The selection of particular metals has been motivated by their prior use as polysulfide absorbers with S cathodes. I further aim to study exactly how and why lithium metal oxides affect (possibly improve) cell performance, their dependence on the M composition and relative oxide fraction and the differences between Li-containing metal oxides and their Li-free metal oxide analogs. Second, I will study a relatively unexplored class of electrolytes that offer reduced viscosity, improved wettability, and sufficient solubility of a broader array of salt additives choices. A range of electrolyte compositions will be screened and studied to understand their behavior in cells.