Date of Award

8-2024

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

Committee Chair/Advisor

Dr. Apparao M. Rao

Committee Member

Dr. Ramakrishna Podila

Committee Member

Dr. Srikanth Pilla

Committee Member

Dr. Endre Takacs

Abstract

The increasing demand for advanced batteries, driven by automotive and energy storage needs, emphasizes the need for improved energy density, longevity, and cost-effectiveness. While lithium-ion batteries (LIBs) offer high energy density, their traditional anode and cathode materials are reaching their limits. Innovations in battery chemistry, particularly using sulfur cathodes and silicon-based anodes, are crucial. Sulfur and silicon are attractive due to their abundance, environmental friendliness, and higher theoretical capacities. This research aims to enhance the electrochemical performance of lithium-sulfur batteries using three-dimensional architectures and solid-state electrolytes, and to improve silicon-based materials by modifying their surface architectures.

Chapter 1 reviews the current state of lithium-ion battery technology, and beyond, highlighting the challenges and strategies to enhance performance.

Chapter 2 discusses various electrochemical characterization and spectroscopic techniques.

Chapter 3 concentrates on developing a porous 3D architecture utilizing the natural porous structure of wood and engineered carbonized delignified wood (CDW) frameworks through a delignification/low-temperature pyrolysis process. Sulfurized polyacrylonitrile (SPAN) is employed as the cathode material due to its ability to inhibit the dissolution of lithium polysulfide.

Chapter 4 focuses on transitioning from liquid electrolyte batteries to solid electrolyte batteries by introducing a cellulose-based separator to enhance battery performance, including improved safety, flexibility, and a wider operating temperature range. This chapter introduces a novel Li-rich cellulose-based solid-state electrolyte fabricated using commercial printing paper.

Chapter 5 emphasizes the enhancement of electronic conductivity and providing a buffer medium for volume change during cycling by modifying the surface architecture. This is accomplished through carbon coating and anchoring reduced graphene oxide (rGO) to silicon particles. The dual carbon-coated silicon demonstrated notable practical applications when combined with NMC for full-cell use.

Chapter 6 explores a method to address Si-related issues by synthesizing high silicon content SiOC materials, where Si bonds with oxygen and carbon. This bonding reduces volume expansion and cracking during the cycling. It also explores SiOC's potential in LIBs with rGO to improve conductivity.

Chapter 7 concludes with a discussion of future research directions, building on the findings from Chapters 3 to 6 to guide further experimentation and development.

Author ORCID Identifier

https://orcid.org/0000-0002-2266-6562

Available for download on Sunday, August 31, 2025

Share

COinS