Shakespeare, Yiana Scott;
(2022)
Transition metal oxide composite nanomaterials as anodes in Lithium-ion energy storage devices.
Doctoral thesis (Eng.D), UCL (University College London).
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Abstract
The work in this thesis explores the use of a Continuous Hydrothermal Flow Synthesis (CHFS) method to create nano-sized transition metal oxides and carbon-metal oxide composites for use as anodic active materials in lithium-ion batteries (LIBs) and hybrid ion capacitors (HICs). In the first study, the novel use of a CHFS method to create the target nanomaterial TiNb2O7, (TNO) was investigated. The electrochemical properties in LIBs were explored. The CHFS TNO exhibited high capacity at low and high currents, good long term cycling stability and prominent levels of pseudocapacitive charge storage. The formation of a composite carbon/TNO material was also explored. This composite material was found to have improved capacity at all currents tested. The second investigation was a materials discovery study centering around tertiary mixed metal oxides. A library of V/Nb/Mo oxides were synthesised and characterised physically and electrochemically in LIBs. The relationships between composition, physical properties and electrochemical behaviour were studied. The novel material, V0.3Nb0.1Mo0.6 oxide (VNM316) was discovered, which showed high capacity at low and high currents. The third study built on the second and investigated the formation of carbon/metal oxide composite materials of the promising VNM composition. Nanoparticles of carbon-VNM316 were successfully synthesised by an assisted CHFS method. These materials showed a large improvement in capacity at high current and performed well as LIB and HIC anodes. Lastly, lessons learnt from previous studies were applied to a library of mixed metal oxides containing Fe, Mn, and Zn. Electrochemical and physical characterisation highlighted the composition Fe0.2Mn0.75Zn0.05. Carbon composite materials based on mixed Fe/Mn/Zn were then formed. The materials C(Fe0.66Mn0.21Zn0.11)-4HT and C(Fe0.72Mn0.17Zn0.09)-5HT displayed high capacities of 932 and 715 mAh g−1 at low current and 271 and 202 mAh g−1 at high current respectively. CV and EIS analysis indicated degradation over long-term cycling causing a drop in capacity retention.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Eng.D |
| Title: | Transition metal oxide composite nanomaterials as anodes in Lithium-ion energy storage devices |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2022. 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 > 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 UCL > Provost and Vice Provost Offices > UCL BEAMS UCL |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10147688 |
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