Hildebrandt, Sandra (2012)
Synthesis and thin film growth of alkaline cobaltates NaxCoO2 and LixCoO2.
Technische Universität Darmstadt
Ph.D. Thesis, Primary publication
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Dissertation Sandra Hildebrandt AL.pdf Copyright Information: CC BY-NC-ND 2.5 Generic - Creative Commons, Attribution, NonCommercial, NoDerivs . Download (5MB) | Preview |
Item Type: | Ph.D. Thesis | ||||
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Type of entry: | Primary publication | ||||
Title: | Synthesis and thin film growth of alkaline cobaltates NaxCoO2 and LixCoO2 | ||||
Language: | English | ||||
Referees: | Alff, Prof. Dr. Lambert ; Donner, Prof. Dr. Wolfgang ; Ensinger, Prof. Dr. Wolfgang ; Albert, Prof. Dr. Barbara | ||||
Date: | 14 December 2012 | ||||
Place of Publication: | Darmstadt | ||||
Date of oral examination: | 18 February 2013 | ||||
Corresponding Links: | |||||
Abstract: | In this study sol-gel synthesis was used to fabricate NaxCoO2, LiNi1/2Co1/2O2 and LiNi1/3Mn1/3Co1/3O2. By using acetate precursors a lower process temperature was accessible, which has a positive effect on the sodium and lithium loss during synthesis. The lithium based powders were single phase and kept cation stoichiometry after sintering. A small grain size is favourable for battery applications. Sodium content was slightly reduced after temperature treatment compared to the initial cation mixture, due to the high volatility of Na. To fabricate thin films PLD was used for deposition. All films were deposited on SrTiO3 substrates. The growth mechanism of NaxCoO2 on SrTiO3 was investigated and an in-plane and out-of-plane relation between film an substrate was found. The films grow 15° and 45° rotated with respect to the ab-plane of the substrate and grow in c-axis direction out-of-plane. The sodium content and the crystallinity of the NaxCoO2 was investigated as a function of the post deposition treatment. A change of x between 0.38 and 0.84 can be achieved. The gamma-phase was preserved in all films despite of the change of the sodium content. The in-situ variation of sodium stoichiometry, allows to tune the film properties in a wide range. This feature is an advantage compared to bulk NaxCoO2, in which only certain stoichiometries can be stabilized. Fabrication of superconducting thin films Na0.33CoO2• 1.3H2O was challenging, since the superconducting phase is metastable and hardly to stabilize as a thin film. LiNi1/3Mn1/3Co1/3O2 and LiNi1/2Co1/2O2 thin films were grown by PLD in (104)-orientation. These thin film materials are promising candidates as cathode materials for the development of thin film batteries. |
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Uncontrolled Keywords: | NaxCoO2, Sol-Gel-Synthesis, LixCoO2, thin film, pulsed laser deposition, epitaxial relation | ||||
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URN: | urn:nbn:de:tuda-tuprints-33716 | ||||
Classification DDC: | 500 Science and mathematics > 500 Science | ||||
Divisions: | 11 Department of Materials and Earth Sciences 11 Department of Materials and Earth Sciences > Material Science 11 Department of Materials and Earth Sciences > Material Science > Advanced Thin Film Technology |
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Date Deposited: | 24 May 2013 08:43 | ||||
Last Modified: | 09 Jul 2020 00:19 | ||||
URI: | https://tuprints.ulb.tu-darmstadt.de/id/eprint/3371 | ||||
PPN: | 386275688 | ||||
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