Direct synthesis of trirutile-type LiMgFeF6 and its electrochemical characterization as positive electrode in lithium-ion batteries
| Autor: | Helmut Ehrenberg, Georg Lieser, Lea de Biasi, Christoph Dräger, Sven Glatthaar, Joachim R. Binder, Sylvio Indris, Michael J. Hoffmann, Holger Geßwein |
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| Rok vydání: | 2015 |
| Předmět: |
Nanocomposite
Materials science Lithium vanadium phosphate battery Renewable Energy Sustainability and the Environment Inorganic chemistry Energy Engineering and Power Technology chemistry.chemical_element Electrochemistry Redox Transition metal chemistry Electrode Fluorine Electrical and Electronic Engineering Physical and Theoretical Chemistry Cyclic voltammetry |
| Zdroj: | Journal of Power Sources. 274:1200-1207 |
| ISSN: | 0378-7753 |
| DOI: | 10.1016/j.jpowsour.2014.10.151 |
| Popis: | The energy density of lithium-ion batteries can be raised by increasing the redox potential of the positive electrode. This can be done in principle by substituting oxygen in commonly used lithium transition metal oxides with the more electronegative fluorine. To synthesize the quaternary lithium transition metal fluoride LiMgFeF 6 with triturile structure a sol–gel process without toxic chemicals was used. The as-synthesized LiMgFeF 6 was ball milled with carbon and binder to characterize the electrochemical properties of the LiMgFeF 6 /carbon/binder nanocomposite against lithium metal. After 20 cycles of galvanostatic cycling a reversible specific capacity of 107 mAh g −1 , which is 80% of the theoretical capacity (1 eq. Li = 133 mAh g −1 ), was retained. In a rate performance test up to a discharge rate of 1C the LiMgFeF 6 /carbon/binder nanocomposite provided a specific capacity of 64 mAh g −1 . Moessbauer spectroscopy and cyclic voltammetry confirmed the electrochemically active redox couple Fe 3+ /Fe 2+ during cycling against lithium metal. Structural changes of the trirutile structure after lithium insertion have been investigated by X-ray powder diffraction. |
| Databáze: | OpenAIRE |
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