| dc.contributor.author | Stevens, David Andrew. | en_US |
| dc.date.accessioned | 2014-10-21T12:33:45Z | |
| dc.date.available | 2000 | |
| dc.date.issued | 2000 | en_US |
| dc.identifier.other | AAINQ66682 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55814 | |
| dc.description | This thesis details the mechanisms for sodium insertion into different carbons using both electrochemical and vapour techniques. Room temperature electrochemical measurements were completed to examine the insertion and removal of sodium from soft (graphitizable) and nanoporous hard (non-graphitizable) carbons prepared by the heat treatment of organic precursors to a range of temperatures. The mechanisms identified from these studies were further investigated through a series of in situ x-ray scattering studies on operating electrochemical cells. The results obtained were then compared with x-ray scattering measurements on carbons after exposure to sodium vapour at 890C. | en_US |
| dc.description | This work is primarily driven by the aluminium industry's need to understand how sodium insertion causes carbon cathode blocks in aluminium reduction cells to swell. The results obtained are also of relevance to the lithium-ion battery field as they help to verify mechanisms proposed in the literature for lithium insertion into carbon hosts. Some carbons were also identified that could accommodate large amounts of sodium, making them attractive candidates for anodes in rechargeable sodium ion batteries. | en_US |
| dc.description | For soft carbons, the results showed that both sodium and lithium insert between approximately parallel carbon layers along the sloping voltage region of the electrochemical curves, increasing the average interlayer spacing. The sodium and lithium capacities decreased with increasing carbon heat treatment temperature. For the soft carbons studied, the sodium capacity was found to be consistently lower than the lithium capacity, implying that some lithium-accessible sites were unavailable for sodium insertion. | en_US |
| dc.description | The electrochemical profiles for the hard carbons also contained capacity along a sloping voltage region and, as with the soft carbons, this was shown to result from the insertion of sodium and lithium between approximately parallel carbon layers. In contrast to the soft carbons, however, the electrochemical profiles for the hard carbons also exhibited significant capacity along low voltage plateaus at chemical potentials close to the chemical potential of the metal. An in situ small angle x-ray scattering experimental method was therefore developed to examine changes in scattering from the nanopores during sodium and lithium insertion/removal. The results from this technique clearly showed that the low voltage plateau capacity resulted from the insertion of sodium and lithium into nanopores in the carbon. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 2000. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Chemistry, Inorganic. | en_US |
| dc.subject | Engineering, Chemical. | en_US |
| dc.subject | Engineering, Materials Science. | en_US |
| dc.title | Mechanisms for sodium insertion in carbon materials. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
