Term of Award

Spring 2022

Degree Name

Master of Science, Applied Physical Science

Document Type and Release Option

Thesis (open access)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Department

Department of Chemistry and Biochemistry

Committee Chair

Ji Wu

Committee Member 1

James LoBue

Committee Member 2

Amanda Stewart

Abstract

Lithium-ion batteries (LIB) are a key aspect of our daily lives, from smartphones to electric vehicles. Commercially available LIB use graphite anodes due to their reliability and safety. Graphite anodes present one key disadvantage: a relatively low theoretical capacity of 372 mAh g-1. It is of great importance that new research focuses on high-capacity anode materials to further our sustainability and usage of LIB. While increasing the performance of LIB is of great interest, developing alternative energy storage devices is gaining attention in academia and industry R&D. Sodium has become a topic of interest in recent years due to sodium’s much higher abundance relative to lithium. Intensive research has been done on one-dimensional morphologies of anode materials, such as nanobelts for lithium/sodium-ion batteries alike. One-dimensional electrode materials are believed to provide superior cycling performance due to the continuous framework for electron transfer they provide. To increase the performance of LIB, molybdenum oxides are considered due to the relatively high theoretical capacity of 838 mAh g-1 for molybdenum dioxide (MoO2). MoO2 has one significant flaw: upon lithiation, a severe volume expansion is experienced. To accommodate this volume expansion we present a scalable, low-cost method of embedding MoO2 nanoplatelets and nanobelts into a conductive carbon asymmetric membrane structure. The large voids within the asymmetric membrane structure can provide an area for the active materials to undergo volume expansion without damaging the electrode. Anodes consisting of both MoO2 nanoplatelets and nanobelts exhibit excellent capacity retentions of 97.3% and 97.4%, respectively, after nearly 160 cycles. In spite of the difference in morphologies used, we have found that the incorporation of either morphology into asymmetric membranes presents highly stable anode materials, as the lithium-ion diffusion is a limiting factor. We also present promising preliminary findings of antimony nanomaterials embedded in asymmetric membranes for sodium-ion battery anodes. It has been determined that the choice of polymer, active material concentration/morphology, and surface coating play important roles in the performance of the anodes. These two projects can further our understanding of LIB/SIB anode materials, as well as present promising alternatives to commercially available energy storage devices.

OCLC Number

1366106364

Research Data and Supplementary Material

No

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