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Correlative investigations into advanced silicon and silicon hybrid anode microstructures for high capacity Li-ion batteries
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Malik, Romeo (2020) Correlative investigations into advanced silicon and silicon hybrid anode microstructures for high capacity Li-ion batteries. PhD thesis, University of Warwick.
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Official URL: http://webcat.warwick.ac.uk/record=b3684447~S15
Abstract
There is a continuing need for global attention to focus on further development of devices to enable efficient energy storage. This must align with a new and stringent renewable energy target of 32 % for the European Union by 2030. Present materials used within Li-ion batteries currently have a limitation on the amount of energy they can store and for a specified duration.
In order to advance the capacity of their most advanced cylindrical cells, Tesla, Samsung, LG and Sony at present use a small fraction of silicon in graphite-dominant anodes to overcome issues around volume expansion and to extend operational life. However, to date, no successful commercial product has been reported that contains silicon as the predominant lithium host material. The solutions offered so far in literature involve complex chemical synthesis or intricate processing routes, which are not realistic solutions to produce practical or cost-effective devices. The thesis core is based on innovative approaches to stabilising silicon-based anodes via additives, which can be conveniently synthesised or commercially available and are chemically compatible with the electrode components.
This research work reports on the use of metal-organic frameworks, namely UiO-66 and UiO-67, to enhance the electrochemical performance of high-capacity silicon anodes in lithium-ion batteries. This research work also studied other hybrid anode systems, based on silicon-graphene and silicon-tin powders, using conventional formulation approaches to compare with an advanced electrode manufacturing technique. This study demonstrates that certain additives improve the flexural capability and mechanical integrity of electrode materials. These additives extend the durability of silicon anodes to enable extended reversible transfer of Li-ions, and hence enable a longer lifespan of the battery.
This study reports the use of high-quality physicochemical characterisation from a variety of experimental techniques to correlate the anode’s microstructure, dynamics and atomic-scale structure with the maintained performance of the battery. Focused ion beam-scanning electron microscopy (FIB-SEM) tomography, in conjunction with impedance spectroscopy and associated physical characterisation, has been employed to capture and quantify key aspects of the evolution of internal morphology and resistance build up within anodes. FIB-SEM tomography has been employed to explore the hierarchical structure of battery electrodes and for diagnosing battery failure mechanisms with high-resolution imaging. This approach will enable us to observe and quantify failures in Li-ion batteries at the electrode level. It is anticipated that this study will influence major improvements in the design of Li-ion battery materials and their processing which in turn positively impact cell performance.
Item Type: | Thesis (PhD) | ||||
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Subjects: | Q Science > QD Chemistry T Technology > TK Electrical engineering. Electronics Nuclear engineering |
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Library of Congress Subject Headings (LCSH): | Lithium ion batteries, Silicon, Anodes, Metal-organic frameworks | ||||
Official Date: | February 2020 | ||||
Dates: |
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Institution: | University of Warwick | ||||
Theses Department: | Warwick Manufacturing Group | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Bhagat, Rohit ; Loveridge, Melanie | ||||
Sponsors: | Engineering and Physical Sciences Research Council ; Faraday Institution ; Warwick Manufacturing Group ; Horizon 2020 (Programme) | ||||
Format of File: | |||||
Extent: | xxvii, 203 leaves : illustrations (some colour) | ||||
Language: | eng |
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