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Title: Characterization and performance of modified 1 M LIPF6: EC: DEC electrolyte for Lithium ion cells
Authors: Mohd Zieauddin Kufian
Keywords: Lithium cells
LiPF6
Electrolyte for Lithium
Liquid electrolyte
EC
DEC
Issue Date: 2009
Publisher: University Malaya
Abstract: In this study, three systems of liquid electrolyte have been investigated. These are 1 M LiPF6:EC:DEC (v/v=1/2) as a baseline electrolyte, Methyl acetate added with baseline electrolyte and ethyl propionate added with baseline electrolyte. The room temperature ionic conductivity for the highest conducting samples in the baseline electrolyte, baseline electrolyte added with 28.6 vol.% of methyl acetate and baseline electrolyte added with 28.6 vol.% of ethyl propionate systems is (5.42 ± 0.20) mS cm-1, (9.62 ± 0.20) mS cm−1 and (8.05 ± 0.16) mS cm−1 respectively. At 50 oC and -30 oC the ionic conductivity of baseline electrolyte is 8.59 mS cm-1 and 0.66 mS cm-1 respectively. Ionic conductivity of the baseline electrolyte added with 28.6 vol.% methyl acetate at 50 oC and -30 oC is 11.4 mS cm-1 and 3.08 mS cm-1 respectively. For baseline electrolyte added with 28.6 vol.% ethyl propionate, the conductivity is 12.6 mS cm-1 and 1.09 mS cm-1 at 50 oC and -30 oC respectively. Linear sweep voltammetry shows that baseline electrolytes with additives decompose at a lower potential compared to baseline electrolyte. However, the decomposition potential is outside the working potential of a liquid lithium ion electrolyte. Fourier transform infrared spectroscopy (FTIR) spectra of methyl acetate and ethyl propionate added baseline electrolytes showed small shifting to lower wavenumbers. Due to the change in conductivity with additive content and with temperature, methyl acetate and ethyl propionate may serve as plasticizers or lubricants that may lead to higher ionic mobility and conductivity. The cells using baseline electrolyte containing 28.6 vol. % of methyl acetate showed the best performance at temperatures -30 oC, -20 oC and 25 oC. This is followed by the cells using 28.6 vol.% of ethyl propionate added electrolyte. However, at 30 oC, the cells using 28.6 vol.% of ethyl propionate added electrolyte has higher capacity than the cells using 28.6 vol.% of methyl acetate added electrolyte.
Description: Dissertation -- Faculty of Science, University of Malaya, 2009.
URI: http://dspace.fsktm.um.edu.my/handle/1812/532
Appears in Collections:Masters Dissertations : Science

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chapter 6.pdfChapter 616.04 kBAdobe PDFView/Open
content.pdfContent15.05 kBAdobe PDFView/Open
TITLE PAGE.pdfTitle Page8.54 kBAdobe PDFView/Open
chapter 5.pdfChapter 543.49 kBAdobe PDFView/Open
chapter 2.pdfChapter 2400.81 kBAdobe PDFView/Open
acknowledgement.pdfAcknowledgement10.08 kBAdobe PDFView/Open
chapter 1.pdfChapter 117.52 kBAdobe PDFView/Open
chapter 4.pdfChapter 48.79 MBAdobe PDFView/Open
chapter 3.pdfChapter 3109.11 kBAdobe PDFView/Open
ABSTRACT ENGLISH.pdfAbstract En.11.84 kBAdobe PDFView/Open
references.pdfReferences38.33 kBAdobe PDFView/Open
ABSTRACT MALAY.pdfAbstract Malay14.38 kBAdobe PDFView/Open
FRONT COVER.pdfFront Page Cover7.04 kBAdobe PDFView/Open


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