Engineering Multifunctional Silicon Nanostructures from Biorenewable Cellulose Nanocrystals

Author

Nancy ChenFollow

Date of Award

5-2024

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Automotive Engineering

Committee Chair/Advisor

Srikanth Pilla

Committee Member

Morteza Sabet

Committee Member

Craig Clemons

Committee Member

Apparao M. Rao

Committee Member

Jiangfeng Zhang

Abstract

The imperative search for alternative materials to address the pressing demand for advance energy storage is underscored by the escalating environmental predicaments. Lithium-ion batteries (LIBs) with graphite anodes have become the benchmark in energy storage; however, they are approaching a saturation point in terms of energy density. Silicon emerges as a promising contender to supplant graphite, owing to its profuse availability, cost-effectiveness, and impressive specific capacity of 4200 mAh g^-1. By integrating silicon anodes, LIBs stand to undergo a radical transformation, markedly diminishing in weight and size, thus heralding a novel wave of compact, lightweight energy storage systems. Nonetheless, the incorporation of silicon in LIBs is not without its share of technical impediments, particularly the volume change (approximately 300%) during electrochemical cycling. This volumetric fluctuation can lead to compromised electrical contacts and diminishing capacity retention through the battery’s lifespan.

In the burgeoning realm of sustainable materials, bio-based substances have carved a niche, capturing attention for their renewable credentials and the potential for realizing high-value end products with minimized ecological footprint. Cellulose, crowned as the planet's most abundant biopolymer, can offer a greener approach to synthesizing Si nanomaterials. This study adopts an economical and eco-conscious method to develop hollow and porous silicon-based anodes, leveraging bio-derived cellulose nanocrystals as a sacrificial template. The resulting silica materials unveil remarkable attributes, including enhanced porosity and a hollow structure, resulting in an exceptionally high surface area and pore volume when compared to commercial products. This research also explores the conversion of silica to elemental silicon while preserving the unique templated morphology, yielding SiNQ materials with performance metrics comparable to commercially available silicon materials. This approach also addresses and mitigates environmental concerns associated with conventional metallothermic conversion processes. Furthermore, we scrutinize the lithium-ion diffusion within SiNQ, whose intricate composition encompasses pure silicon, silicon monoxides, and silicon dioxide. Employing GITT, we evaluate SiNQ's electrochemical attributes, focusing on kinetic rate constants and transport properties. This investigation strives to reconcile the promise of silicon-based anodes with their practical deployment in LIBs, advancing towards high-performance, environmentally responsible energy storage solutions.

Recommended Citation

Chen, Nancy, "Engineering Multifunctional Silicon Nanostructures from Biorenewable Cellulose Nanocrystals" (2024). All Dissertations. 3603.
https://tigerprints.clemson.edu/all_dissertations/3603

Author ORCID Identifier

0000-0002-5377-1314