Abstract
dc:description.abstractThe development of safer, more energy-dense rechargeable batteries is crucial for advancing electric vehicle technology and renewable energy integration to meet the Paris Agreement. Real-time monitoring of chemical processes within the cell is essential, but the complex and volatile nature of battery components makes the integration of diagnostic sensors non-trivial. Combining optical fibres and spectroscopy provides a chemically sensitive sensor that can be embedded directly into the battery with minimal disturbance to the cell operation. This thesis aims to develop and characterise an operando fibre-optic Raman probe, enhanced solely by optical phenomena, sensitive to the intricate and evolving surface chemistries within the cell. Experimental methods used in this thesis included optical characterisation of the forward excitation and signal collection capabilities of the fibre-probe, and ex-situ Raman measurements, using high-refractive-index microspheres and carefully selected test samples. A methodology for operando fibre-Raman analysis of battery electrolyte in lab-based electrochemical cells was developed, to correlate with future surface Raman studies. The findings demonstrated that high-refractive-index microspheres increase the intensity of sample excitation and increase the efficiency of multimodal collection of near-infrared light. In combination, this significantly improves the Raman signal collected by the fibre probe, making it more surface-sensitive. The results indicate promising potential for this surface-sensitive Raman-fibre probe in battery diagnostics. This thesis establishes a protocol for evaluating various fibre and microlens combinations, which can be used to optimise the excitation and collection for any sample. This thesis confirms that adding a microlens enhances the Raman scattering collected by a hollow core fibre. However, challenges remain, particularly in making the probe liquid-tight for practical applications. The operando liquid-fibre Raman methodology developed is suitable for lab-scale full and half-cell electrochemical studies, paving the way for correlated liquid and surface measurements, and investigations into new battery chemistries.
Degree
thesis:*- Name dc:type.qualificationname
- Doctor of Philosophy (PhD)
- Level dc:type.qualificationlevel
- Doctoral
- Grantor dc:publisher.institution
- University of Cambridge
- Year dc:date.issued
- 2024
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Groom, Megan Jessica
- Advisors dc:contributor.advisor
-
- Euser, Tijmen G
- Baumberg, Jeremy J
Subjects
dc:subject × 5Rights
dc:rightsIdentifiers
dc:identifier.*- DOI dc:identifier.doi
- https://doi.org/10.17863/CAM.115210
- OAI identifier oai:identifier
- oai:www.repository.cam.ac.uk:1810/378990