Sykes, Daniel;
(2024)
Materials for Renewable Energy: A study of cathode materials for sodium-ion batteries, and solar cell absorbers.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Climate change and its consequences have been at the centre of mainstream scientific discussion for decades. Since 1998, the concentration of atmospheric CO2 has risen from around 366 parts per million (ppm) to 414 ppm in 2021. This rise which occurs predominately from the burning of fossil fuels for power and transport must be slowed to maintain a stable and liveable climate. To this end, a transition away from fossil fuel power sources towards renewables is necessary. Renewable energy sources such as solar and wind do not emit CO2 and other pollutants during their operation, but they suffer from efficiency and formidable intermittency issues that inhibit their mainstream commercial adoption. The problem of intermittency may be overcome with stationary battery storage. To this end, sodium-ion batteries have recently become the target of much research over the last two decades. Sodium-ion batteries can fill this need for stationary storage where lithium-ion batteries may not be due to prohibitive scarcity. Additionally, improvements to renewable energy sources such as solar cell absorbers have been actively sought out. The discovery of methyl-ammonium lead iodide in 2009 has shown that perovskite-like structures can serve as excellent candidate materials. To further knowledge of these technologies, in this thesis, promising sodium-ion cathodes Na2FePO4F, Na2Fe2F7 and Na2FeVF7, as well as a group of novel vacancy-ordered quadruple perovskites (VOQPs) have been studied using first-principles density functional theory (DFT) calculations. A comprehensive defect study is carried out on Na2FePO4F to establish a quantitative survey and thorough workflow for finding ground-state defect structures. The polymorphs of weberite systems Na2Fe2F7 and Na2FeVF7 and any different electronic properties they have were investigated. Finally, a selection of twelve novel VOQPs underwent calculations to establish their potential optoelectronic properties as well as their thermodynamic and dynamic stability as candidates for potential solar cell absorbers.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Materials for Renewable Energy: A study of cathode materials for sodium-ion batteries, and solar cell absorbers |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2024. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10188462 |
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