The subject of this thesis is the application of magnetic resonance methods to the characterization and quantification of lithium-ion transport in a wide range of lithium-ion battery electrolyte materials relevant to the electromobility and energy storage sectors. In particular, field-gradient magnetic resonance techniques, in the form of PFG-NMR diffusivity measurements of both liquid- and solid-state electrolytes and in situ MRI of electrochemical cells, comprise the core means by which these characterizations were performed. PFG-NMR and ionic conductivity studies of a range of liquid-state electrolyte mixtures were performed, as a function of temperature, to assess how key mass and charge transport properties reflect differences in composition. In situ MRI was used to study the effect of temperature on steady-state concentration gradient formation in polarized liquid electrolytes, with the results quantitatively compared to model predictions. This approach was then extended, using a combination of MRI and spatially-resolved PFG-NMR, to study the interlinked effects of temperature and current density on concentration gradient formation, and to attempt a comprehensive characterization of the ion transport parameters with spatial resolution. Finally, PFG-NMR and MAS-NMR were applied in a solid-state electrolyte context to investigate compositional effects on ion transport in the argyrodite family of lithium-sulphide ion conductors, and the influence of macroscopic sample format (glass, crystalline powder, compressed crystalline pellet) on micro-scale ion transport in a thio-LISICON ion conductor. Taken together, the studies demonstrate the effectiveness of magnetic resonance methods for the robust elucidation of the means by which material properties impact ion transport in technologically-relevant lithium-ion electrolyte systems. / Dissertation / Doctor of Science (PhD) / Lithium-ion batteries are a critical component of the ongoing efforts to transition the global automobile fleet to electric vehicles and integrate renewable energy sources into the electricity grid. An important aspect of designing and optimizing lithium-ion batteries is a comprehensive understanding of the factors which impact the ability of the electrolyte in the battery to ferry the lithium ions from one electrode to the other, the process which enables them to release energy into the circuit to power a device. This thesis describes results obtained from measuring the diffusion of the ions within the electrolyte for both conventional liquid-state electrolytes, and emerging solid-state electrolyte materials. It also includes studies which make use of MRI to image the flow of ions within the liquid-state electrolyte of an operating battery mimic, and monitor the concentration changes of the ions across the electrolyte as a current is applied to it.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/25193 |
| Date | January 2020 |
| Creators | Bazak, Jonathan David |
| Contributors | Goward, Gillian, Chemistry and Chemical Biology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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