Kaspar, Jan ; Graczyk-Zajac, Magdalena ; Riedel, Ralf (2013)
Lithium insertion into carbon-rich SiOC ceramics: Influence of pyrolysis temperature on electrochemical properties.
In: Journal of Power Sources, 244
doi: 10.1016/j.jpowsour.2012.11.086
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
Carbon-rich silicon oxycarbide ceramics (SiOC) prepared via thermal conversion of polyorganosiloxane demonstrate high lithiation capacity and reliable rate capability when used as anode material in Li-ion batteries. The electrochemical properties of carbon-rich SiOC are strongly related to microstructure and phase composition, dependent on final pyrolysis temperature. Both, the increasing organization of free carbon segregated within the microstructure and the gradual degradation of the amorphous Si–O–C network with increasing pyrolysis temperature (Tpyr) lead to reduced capacities and changing voltage profiles. Within our study, the highest registered capacity of 660 mAh g−1 for Tpyr = 900 °C dropped below 80 mAh g−1 for SiOC pyrolyzed at 2000 °C. A continuous decrease in capacity is observed, when increasing Tpyr stepwise by 100 °C, which can be explained by major microstructural changes. First, the free carbon within the ceramic microstructure organizes toward higher ordered configurations, as determined by Raman spectroscopy. Second, X-ray powder diffraction demonstrates a decomposition of the amorphous Si–O–C network resulting in SiC crystallization and growth of SiC domains. Simultaneously, FTIR spectroscopy shows a strong increase of Si–C vibration with Tpyr, while Si–O vibration diminishes and almost disappears after annealing at 1700–2000 °C. According to our study we find, that i) increasing carbon organization provides less Li-ion storing sites, ii) gradual Si–O–C network decomposition reduces the structural stability of the free carbon phase and iii) formation of electrochemically inactive SiC account for reduced capacities and changing voltage profiles with increasing Tpyr.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2013 |
| Autor(en): | Kaspar, Jan ; Graczyk-Zajac, Magdalena ; Riedel, Ralf |
| Art des Eintrags: | Bibliographie |
| Titel: | Lithium insertion into carbon-rich SiOC ceramics: Influence of pyrolysis temperature on electrochemical properties |
| Sprache: | Englisch |
| Publikationsjahr: | 15 Dezember 2013 |
| Verlag: | Elsevier Science Publishing |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Journal of Power Sources |
| Jahrgang/Volume einer Zeitschrift: | 244 |
| DOI: | 10.1016/j.jpowsour.2012.11.086 |
| Kurzbeschreibung (Abstract): | Carbon-rich silicon oxycarbide ceramics (SiOC) prepared via thermal conversion of polyorganosiloxane demonstrate high lithiation capacity and reliable rate capability when used as anode material in Li-ion batteries. The electrochemical properties of carbon-rich SiOC are strongly related to microstructure and phase composition, dependent on final pyrolysis temperature. Both, the increasing organization of free carbon segregated within the microstructure and the gradual degradation of the amorphous Si–O–C network with increasing pyrolysis temperature (Tpyr) lead to reduced capacities and changing voltage profiles. Within our study, the highest registered capacity of 660 mAh g−1 for Tpyr = 900 °C dropped below 80 mAh g−1 for SiOC pyrolyzed at 2000 °C. A continuous decrease in capacity is observed, when increasing Tpyr stepwise by 100 °C, which can be explained by major microstructural changes. First, the free carbon within the ceramic microstructure organizes toward higher ordered configurations, as determined by Raman spectroscopy. Second, X-ray powder diffraction demonstrates a decomposition of the amorphous Si–O–C network resulting in SiC crystallization and growth of SiC domains. Simultaneously, FTIR spectroscopy shows a strong increase of Si–C vibration with Tpyr, while Si–O vibration diminishes and almost disappears after annealing at 1700–2000 °C. According to our study we find, that i) increasing carbon organization provides less Li-ion storing sites, ii) gradual Si–O–C network decomposition reduces the structural stability of the free carbon phase and iii) formation of electrochemically inactive SiC account for reduced capacities and changing voltage profiles with increasing Tpyr. |
| Freie Schlagworte: | Li-ion battery; Anode; Carbon-rich SiOC; Influence of pyrolysis; Temperature; High capacity |
| Zusätzliche Informationen: | SFB 595 A4 16th International Meeting on Lithium Batteries (IMLB) |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Disperse Feststoffe Zentrale Einrichtungen DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche > SFB 595: Elektrische Ermüdung DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche > SFB 595: Elektrische Ermüdung > A - Synthese DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche > SFB 595: Elektrische Ermüdung > A - Synthese > Teilprojekt A4: Neue Funktionskeramiken durch Anionensubstitution in oxidischen Systemen 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche DFG-Sonderforschungsbereiche (inkl. Transregio) |
| Hinterlegungsdatum: | 07 Jan 2013 14:16 |
| Letzte Änderung: | 21 Feb 2014 08:36 |
| PPN: | |
| Sponsoren: | The authors acknowledge the financial support by the Deutsche Forschungsgemeinschaft (DFG), Bonn, Germany within SPP1473/JP8 and SFB 595/A4 program. |
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