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Title: The electrochemical production of filled carbon nanotubes and their use as anode materials in lithium-ion batteries
Author: Das Gupta, R.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2010
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This thesis examines the electrochemical production of filled carbon nanotubes and their application in lithium-ion batteries. Tin filled carbon nanotubes were produced via an electrolysis process in mixed LiCl/SnCl2 electrolytes with graphite electrodes at 775°C. The reaction mechanism of the production process was investigated, in addition to the relationship between the physical and chemical properties of the post-electrolysis product and the experimental method/conditions used. The link between the post-electrolysis product’s composition and morphology and their electrochemical performance in lithium-ion batteries was also analysed in detail. A variety of experimental setups and electrolytic processes were compared. The electrolytic production processes examined included constant current electrolysis, constant voltage electrolysis with respect to a molybdenum pseudo reference and a switching electrolysis with respect to the molybdenum reference using two identical electrodes where the polarity was changed after a set time. The novel switching electrolysis method was examined in most detail due to the superior product and consistency results achieved. An optimised switching electrolysis procedure was developed. To assess their potential use as a lithium-ion battery anode material, the post-electrolysis material containing tin filled carbon nanotubes were examined as the active material in half-cells. The cells were composed of lithium metal foil as the counter electrode and a mixture containing a majority of post electrolysis material along with carbon black, binder and in the case of some cells, graphite, as the working electrode. The post-electrolysis material displayed promising characteristics, with high capacity and stable cycling performance. The post-cycled electrode material was characterised by SEM and HRTEM to assess changes to the morphology of the electrode material resulting from the cycling environment.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available