Structural Changes in a High-Energy Density VO2F Cathode upon Heating and Li Cycling
| Autor: | Jatinkumar Rana, Natasha A. Chernova, Yuh-Chieh Lin, M. Stanley Whittingham, Iek-Heng Chu, Shyue Ping Ong, Khim Karki, Fredrick Omenya, Shawn Sallis, Xiaoya Wang, Hui Zhou, Louis F. J. Piper |
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| Rok vydání: | 2018 |
| Předmět: |
Thermogravimetric analysis
Materials science Energy Engineering and Power Technology chemistry.chemical_element 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Electrochemistry 01 natural sciences Vanadium oxide Lithium-ion battery 0104 chemical sciences chemistry Materials Chemistry Chemical Engineering (miscellaneous) Physical chemistry Thermal stability Lithium Electrical and Electronic Engineering Absorption (chemistry) 0210 nano-technology Inert gas |
| Zdroj: | ACS Applied Energy Materials. 1:4514-4521 |
| ISSN: | 2574-0962 |
| Popis: | Structural changes in VO2F, which allow two-electron transfer during electrochemical Li cycling, were investigated. This compound adopts a rhombohedral structure, space group R3c, with O and F sharing one site, and was synthesized by high-energy ball-milling. The thermal stability of VO2F, which is related to the battery safety, is studied by in situ XRD upon heating and by thermal gravimetric analysis. VO2F is found to be stable up to 160 °C under inert atmosphere; above this temperature, it converts into vanadium oxide with fluorine loss. The structure evolution upon lithium cycling was studied by ex situ X-ray diffraction and absorption techniques. The results show that lithiation of VO2F goes through a solid-solution reaction, and the rhombohedral structure is preserved if no more than one lithium ion is intercalated. Upon a second Li insertion, an irreversible transition to a rock-salt structure occurs. We show using first-principles calculations that this irreversible transformation can be explaine... |
| Databáze: | OpenAIRE |
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