This body of work is tackling some of the challenges in the field of lithium-ion
batteries (LIBs) for electric vehicles through in situ nuclear magnetic resonance
(NMR). In situ NMR allows for the simultaneous monitoring of both liquid and
solid components (electrolyte, cathode, anode, separator) and provides timely
data acquisition making it a great method to extract real-time information
about structural changes, degradation products and failure mechanisms in
batteries.
A combined in situ 7Li NMR and ex situ 29Si magic-angle spinning (MAS)
NMR study on silicon and silicon monoxide was used to compare structural
differences in these anode materials using a custom-made in situ cell. Some
key differences between the two materials were obtained, highlighting the
importance of in situ NMR to be used for identifying phases, which are not
present under ex situ conditions. In addition, fast charging of silicon anodes was
investigated to gain a better understanding of their performance at high current
rates. Magnetic resonance imaging was also implemented to localize lithium
metal deposition under these conditions, which was made possible by a unique
in situ parallel-plate resonator setup. Finally, the successful development of a
novel in situ MAS NMR technique is introduced, which for the first time allows
for an in situ analysis of a LIB under MAS. This strategy paves the way toward
acquisition of valuable in situ data on the formation and transformations of
metastable states within the active materials of both electrodes; data that is
difficult to obtain from static in situ NMR experiments alone. / Thesis / Doctor of Philosophy (PhD)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/26114 |
| Date | January 2020 |
| Creators | Freytag, Annica I. |
| Contributors | Goward, Gillian R., Chemistry and Chemical Biology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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