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An Electron Paramagnetic Resonance (EPR) study of battery and functional materials

Spencer, Jacob 2021. An Electron Paramagnetic Resonance (EPR) study of battery and functional materials. PhD Thesis, Cardiff University.
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Abstract

The optimisation of solid-state functional materials towards the desired redox activity, optical or magnetic properties is fundamental in the understanding and development of important industrial materials. These properties are generally afforded by the inclusion of metal ions, point defects, or other local centres that can participate in single-electron transfer processes. Electron Paramagnetic Resonance (EPR) spectroscopy is clearly a powerful, but often under-utilised tool in their characterisation and development. Chelating exchange resins (CERs) are a widely used technology for metal extraction in aqueous acidic media. A systematic CW EPR study was performed on a range of model complexes to identify uptake and speciation of Cu2+ within two commercial chelating exchange resins, Dowex M4195 and CuWRAM. Rare earth activated phosphors have long been of interest owing to their efficient luminescent properties and tuneability, for a variety of optical applications. A series of commercial and prepared CaS:Eu2+ phosphors were investigated to understand process control and defect chemistry with respect to their luminescent properties. Disordered glassy materials have attracted considerable interest for application as solid-state Li-ion battery components. The local defect structure was investigated for a series of LiBO2-V2O5 mixed conductive glasses of varying V2O5 content, providing a detailed insight into distinct network-forming and modifying sites. The characterisation of Li-ion battery materials is a critical aspect in the continued development of energy storage systems. A systematic ex situ EPR investigation of common electrode materials was performed to understand the relation of local electronic structure, and electrochemical activity. The development of a home-built in situ electrochemical cell was also presented, with respect to the challenges of in situ electrochemical measurements. The outcomes of this work have illustrated that through careful investigation, EPR can provide a mechanistic understanding of important commercially relevant function materials often not available via other techniques.

Item Type: Thesis (PhD)
Date Type: Completion
Status: Unpublished
Schools: Chemistry
Date of First Compliant Deposit: 15 June 2021
Last Modified: 15 Jun 2021 09:37
URI: http://orca.cardiff.ac.uk/id/eprint/141901

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