Publication Date


Document Type


Committee Members

David Grossie (Committee Member), Vladimir Katovic (Advisor), Suzanne Lunsford (Committee Member)

Degree Name

Master of Science (MS)


Finding a cathode material to operate a high-temperature Li-ion battery in the presence of an ionic liquid has become an attractive area of research. Three cathode materials, LiCoO2, Li4Ti5O12, and LiFePO4, were received from Electrochemical Systems Inc. of Knoxville, TN. Three ionic liquids were synthesized using a 1-alkyl-3-methylimidazolium (XMI+) cation, where the alkyl group was either ethyl, pentyl or hexyl, and contained a bis(pentafluoroethylsulfonyl)imide (Beti-) anion. The thermal and electrochemical properties of each ionic liquid, of each cathode material, and each combination of cathode material in the presence of ionic liquid were studied. All of the ionic liquids were found to be thermally stable to nearly 400 °C. Potential windows of the ionic liquids increased when chain length increased from 4.3 V (EMIBeti) to 4.8 V (HMIBeti). All cathode materials begin to lose mass significantly sooner than the ionic liquids, around 200 °C. LiCoO2 in the presence of EMIBeti was the most thermally stable material at ~ 416 °C. Cyclic voltammograms of the cathode materials in the presence of ionic liquids showed potential windows of ~4 V.

Page Count


Department or Program

Department of Chemistry

Year Degree Awarded


Included in

Chemistry Commons