Understanding and optimizing the interfacial mechanisms of next-generation energy storage and conversion materials

Thornburg, Eric Scott

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https://hdl.handle.net/2142/122038 Copy

Description

Title

Understanding and optimizing the interfacial mechanisms of next-generation energy storage and conversion materials

Author(s)

Thornburg, Eric Scott

Issue Date

2023-12-01

Director of Research (if dissertation) or Advisor (if thesis)

Gewirth, Andrew A.

Doctoral Committee Chair(s)

Gewirth, Andrew A.

Committee Member(s)

• Murphy, Catherine J.
• Nuzzo, Ralph G.
• Chen, Qian

Department of Study

Chemistry

Discipline

Chemistry

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• lithium
• sulfur
• batteries
• electrolyte
• characterization
• electrochemistry

Abstract

The general intent of the work presented in this dissertation is to jointly leverage the capabilities of modern chemical research and characterization methods to advance the development of energy-relevant materials. Of primary focus is the interrogation of the interfacial (electro)chemical mechanisms that underpin the failure modes of next-generation, rechargeable Li metal and S batteries. By making small, but rationally designed alterations to a single component of a battery cell prior to assembly and tracking the cascading effects of these alterations throughout the life of the cell, this research aims to isolate and reveal specific chemical pathways that can be further tuned to achieve the capacity, stability, and longevity demanded of batteries by a world of ever-increasing energy consumption. After introducing the ground principles of current (Li-ion) and future (Li-S) rechargeable battery chemistries in chapter 1, two specific efforts guided by the goals stated above are detailed herein. The first effort, in chapter 2, is centered on the surface modification of Li metal anodes designed for multiple battery chemistries. Following the brief exposure of pristine Li electrodes to two analogous halogenated solvents, high stability is observed in long-term cycling using a previously incompatible electrolyte formulation, and valuable insights about the interplay of electrolyte components and Li surface speciation are established. The second effort, in chapter 3, is centered on S cathodes, specifically targeting the improvement of their electrochemical performance when cycled together with Li metal anodes. Here, the simple addition of two similar heterocyclic electrolyte cosolvents shifts electrolyte properties and solvation dynamics to help mitigate S shuttling and improve capacity retention, rate capability, and activation and utilization of S cathodes. Last, in chapter 4, the scope of this dissertation broadens somewhat. Three examples of the use of advanced characterization methods to inform mechanistic understandings of the operative structural and chemical features at the interfaces of Co-containing O2 reduction catalysts, bimetallic Cu-alloy NO3- reduction catalysts, and Co-decorated catalytic host materials for S cathodes in Na-S batteries are described. The two techniques of interest, TEM and XPS, elucidate nanoscale morphological differences, surface-localized oxidation discrepancies, and both compositional and microstructural transformations.

Graduation Semester

2023-12

Type of Resource

Thesis

Copyright and License Information

Copyright 2023 Eric Thornburg

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