Date of Graduation

Summer 2024

Degree

Master of Science in Materials Science

Department

Physics, Astronomy, and Materials Science

Committee Chair

Saibal Mitra

Abstract

High energy density materials have evolved energy storage systems to cope with rising demand for environmental friendly power. On this ground, quartz and stainless substrates were utilized to prepare LiCoO2 thin films on quartz and stainless steel (SS) substrates at the temperatures of 400, 650°C, and 700°C using pulsed laser deposition (PLD) technique. The oxygen (O2) partial pressure was maintained at 10 mTorr and 100 mTorr during the deposition. X-ray diffraction (XRD) study confirmed the rhombohedral structure with the R3m space group of the prepared LiCoO2 films. Using Raman spectroscopy, the vibrational modes were recognized and the films' multi-phase nature was confirmed, yielding the structural hallmark of the deposited films. UV-VIS investigation determined that the optical bandgap of films grown on quartz substrates spans between 2.27 eV and 2.52 eV. Electrical analysis of the films produced on quartz substrates demonstrated that films grown under increased O2 pressure have a greater DC electrical conductivity, with the electrical conductivity ranging from 4.5×10-8 S cm-1 to 4.1×10-3 S cm-1. The highest discharge capacity of 30.10 µA.h/cm².µm was measured for Sample-2_SS_650°C_10 mTorr. Over the duration of ten cycles, the cell's discharge capacity stayed constant.

Keywords

LiCoO2, crystal structure, bandgap, conductivity, discharge capacity.

Subject Categories

Condensed Matter Physics

Copyright

© Fahad Munshe

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Available for download on Sunday, May 30, 2027

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