The synthesis and structure of transition metal oxides for battery applications
The synthesis and structure of transition metal oxides for battery applications
The Synthesis and Structure of Transition Metal Oxides for Battery Applications by Matthew James Oliver Low temperature hydrothermal routes to bismuth (V) containing materials have been investigated. Results indicate that MgBiaOe, obtained by the hydrothermal reaction of magnesium chloride with sodium bismuthate, crystallises with a trimtile-type structure. Attempts to synthesise the equivalent calcium compound yielded CaiBiiO?, which was found to adopt a pyrochlore structure. The attempted synthesis of the strontium equivalent produced a material with an X-ray diffraction pattern indicative of a layered material with an inter-layer separation of 13.657(4)A. Single phase products were not obtained under a wide variety of reaction conditions in the case of Zn, Cd, and Ba. Two new alkali metal iron oxide materials have been synthesised, RbFeOi and CsFeOi. The structures of these two compounds have been investigated using powder X-ray diffraction and time of flight powder neutron diffraction. Powder neutron data confirmed an orthorhombic space group, Pbca, for KFeOz and RbFeOi and a cubic space group, Fd-3m, for CsFeOa. The increased symmetry, as a result of incorporating the larger cations into the structure, is reflected by an opening up of the Fe-O-Fe bond angle from 136.1° (KFe02) to 151.69° (RbFeOi) and 180° (CsFe02). Preliminary attempts at exchanging the potassium ion for lithium in these structures were inconclusive but energy dispersive X-ray analysis and ion-conduction data from related compounds indicate that this may be feasible. Hydrothermal reactions at high-pressures (up to 40000psi) and high temperatures (700°C) were utilised to try and synthesise structures containing manganese stabilised in unusually high oxidation states. The potassium equivalent of the mixed valent NaiMngOy could not be formed. X-ray diffraction data pointing to the formation of KuaMngOiG with the hollandite structure.
University of Southampton
Oliver, Matthew James
5de922ed-5c71-4dfb-9b69-35e7fafdbc27
2002
Oliver, Matthew James
5de922ed-5c71-4dfb-9b69-35e7fafdbc27
Oliver, Matthew James
(2002)
The synthesis and structure of transition metal oxides for battery applications.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The Synthesis and Structure of Transition Metal Oxides for Battery Applications by Matthew James Oliver Low temperature hydrothermal routes to bismuth (V) containing materials have been investigated. Results indicate that MgBiaOe, obtained by the hydrothermal reaction of magnesium chloride with sodium bismuthate, crystallises with a trimtile-type structure. Attempts to synthesise the equivalent calcium compound yielded CaiBiiO?, which was found to adopt a pyrochlore structure. The attempted synthesis of the strontium equivalent produced a material with an X-ray diffraction pattern indicative of a layered material with an inter-layer separation of 13.657(4)A. Single phase products were not obtained under a wide variety of reaction conditions in the case of Zn, Cd, and Ba. Two new alkali metal iron oxide materials have been synthesised, RbFeOi and CsFeOi. The structures of these two compounds have been investigated using powder X-ray diffraction and time of flight powder neutron diffraction. Powder neutron data confirmed an orthorhombic space group, Pbca, for KFeOz and RbFeOi and a cubic space group, Fd-3m, for CsFeOa. The increased symmetry, as a result of incorporating the larger cations into the structure, is reflected by an opening up of the Fe-O-Fe bond angle from 136.1° (KFe02) to 151.69° (RbFeOi) and 180° (CsFe02). Preliminary attempts at exchanging the potassium ion for lithium in these structures were inconclusive but energy dispersive X-ray analysis and ion-conduction data from related compounds indicate that this may be feasible. Hydrothermal reactions at high-pressures (up to 40000psi) and high temperatures (700°C) were utilised to try and synthesise structures containing manganese stabilised in unusually high oxidation states. The potassium equivalent of the mixed valent NaiMngOy could not be formed. X-ray diffraction data pointing to the formation of KuaMngOiG with the hollandite structure.
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Published date: 2002
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Local EPrints ID: 465062
URI: http://eprints.soton.ac.uk/id/eprint/465062
PURE UUID: 409620f9-5d56-4497-8e5e-b414a1b41df1
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Date deposited: 05 Jul 2022 00:20
Last modified: 16 Mar 2024 19:55
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Matthew James Oliver
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