Date of Award

8-2024

Document Type

Campus Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry/Physical/Analytical Chemistry

First Advisor

Niya Sa

Second Advisor

Neil Reilly

Third Advisor

Daniel Dowling, Matthew Bell

Abstract

Alloy-type anodes, such as silicon (Si) and tin (Sn), are among the most promising next-generation battery materials due to their high theoretical specific capacity, abundant availability, and cost-effectiveness. However, their practical application is hindered by several challenges, including the instability of the solid electrolyte interface (SEI), exacerbated by substantial volume changes during charging and discharging cycles, leading to rapid capacity decay and a shortened cycle life. Furthermore, there are considerable gaps in the fundamental understanding of the complex alloying processes and SEI evolution at the anode/electrolyte interface. This thesis addresses these gaps through a quantitative in situ investigation of the SEI formation and evolution at Si in conventional Li electrolytes and lays the groundwork for mechanisms of stabilizing the interfaces by implementing a binary cation matrix. This work highlights the advantages of a tailored electrolyte environment, revealing significant improvements in SEI stability on Si and offering valuable insights into the interfacial viscoelastic and electronic properties. Beyond Li-ion technology, this thesis explores the three-dimensional structural and phase evolution of Sn anodes in Ca electrolytes under various voltage conditions. This breakthrough knowledge holds the potential to revolutionize the development of high-performance, cost-effective multivalent battery systems with superior energy density. The employed methodologies are extended beyond the anode/electrolyte chemistries to investigate the Prussian Blue (PB) cathode, which is of interest due to its ability to accommodate various-sized cations and its effectiveness in both aqueous and non-aqueous electrolytes. New insights into the concentration-dependent intercalation processes of PB in potassium-based aqueous electrolytes are revealed. This research delivers a comprehensive understanding of the electrochemical processes at electrode/electrolyte interfaces. It sheds light on the mechanisms governing reaction dynamics, SEI evolution, and stability and paves the way for the next generation of high-performance energy storage systems.

Comments

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Signature page.pdf (615 kB)

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