"Raman Spectroscopic and Quantum Chemical Investigation of Ethylene Car" by Kenneth T. Arnett and Nathan I. Hammer
 

Honors Theses

Date of Award

Spring 5-10-2025

Document Type

Undergraduate Thesis

Department

Chemistry and Biochemistry

First Advisor

Nathan Hammer

Second Advisor

Ryan Fortenberry

Third Advisor

Sujay Ray

Relational Format

Thesis

Abstract

Lithium-ion batteries are a critical component of modern technology and are responsible for providing power for many devices. However, these batteries are not permanent, even if they are rechargeable. Over time, battery life dwindles and eventually completely disappears. For lithium-ion batteries, this degradation is partially due to the solid electrolyte interface, which is formed by a reaction of ethylene carbonate with other molecules and electrons inside the battery itself. In this paper, the properties of ethylene carbonate are investigated using computational methods and through Raman spectroscopy. The results of the computational work indicate that the five-membered ring, which is not planar, begins to flatten out when under H-bonding interactions. This change in point group has not been reported previously. The other computational results are that many vibrational modes agree with experimental results, with the notable exception of a C=O band for pure ethylene carbonate. The most likely reason for this discrepancy between the simulated Raman spectrum and the observed Raman spectrum is the crystalline structure, which was not accounted for in the calculation input file due to the additional computational load. In order to simulate a polar environment like the inside of a battery, clusters of both water and methanol were also performed. The agreement between the methanol cluster computational data and experimental data was much better than clusters of water, and several peaks could be assigned. Some peaks, particularly those involving C-H and C=O vibrational modes, suggest that multiple clusters are present experimentally.

Available for download on Tuesday, May 02, 2028

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