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Silicon oxycarbide/nano-silicon composite anodes for Li-ion batteries: Considerable influence of nano-crystalline vs. nano-amorphous silicon embedment on the electrochemical properties

Kaspar, Jan and Graczyk-Zajac, Magdalena and Lauterbach, Stefan and Kleebe, Hans-Joachim and Riedel, Ralf (2014):
Silicon oxycarbide/nano-silicon composite anodes for Li-ion batteries: Considerable influence of nano-crystalline vs. nano-amorphous silicon embedment on the electrochemical properties.
In: Journal of Power Sources, pp. 164-172, 269, ISSN 03787753, [Online-Edition: http://dx.doi.org/10.1016/j.jpowsour.2014.06.089],
[Article]

Abstract

Silicon oxycarbide/nano-silicon composites (SiOC/nSi) are prepared by mixing of nano-sized silicon, either crystalline (nSi_c) or amorphous (nSi_a), with commercially available polyorganosiloxane RD-684a and subsequent pyrolysis. The influence of the type of nano-silicon, namely crystalline vs. amorphous, on the electrochemical properties and performance is analyzed and correlated with the corresponding composite microstructure. In the case of crystalline nano-silicon, a high reversible capacity of 905 mAh g−1 is registered, whereas that for amorphous nano-silicon embedment reaches 704 mAh g−1. However, regarding the cycling stability, SiOC/nSi_c shows a significant capacity fading upon continuous cycling, related to SiOC matrix failure. The host phase is not able to accommodate the arising mechanical stresses upon Si grain expansion and contraction when alloying/dealloying with Li. SiOC/nSi_a on the contrary, demonstrates a stable cycling performance for up to 100 cycles. This excellent performance is explained by the enhanced matrix integrity of the compound, rationalized by a smaller size of the embedded crystallized Si grains and an intrinsically enhanced electrical conductivity due to the formation of SiC.

Item Type: Article
Erschienen: 2014
Creators: Kaspar, Jan and Graczyk-Zajac, Magdalena and Lauterbach, Stefan and Kleebe, Hans-Joachim and Riedel, Ralf
Title: Silicon oxycarbide/nano-silicon composite anodes for Li-ion batteries: Considerable influence of nano-crystalline vs. nano-amorphous silicon embedment on the electrochemical properties
Language: English
Abstract:

Silicon oxycarbide/nano-silicon composites (SiOC/nSi) are prepared by mixing of nano-sized silicon, either crystalline (nSi_c) or amorphous (nSi_a), with commercially available polyorganosiloxane RD-684a and subsequent pyrolysis. The influence of the type of nano-silicon, namely crystalline vs. amorphous, on the electrochemical properties and performance is analyzed and correlated with the corresponding composite microstructure. In the case of crystalline nano-silicon, a high reversible capacity of 905 mAh g−1 is registered, whereas that for amorphous nano-silicon embedment reaches 704 mAh g−1. However, regarding the cycling stability, SiOC/nSi_c shows a significant capacity fading upon continuous cycling, related to SiOC matrix failure. The host phase is not able to accommodate the arising mechanical stresses upon Si grain expansion and contraction when alloying/dealloying with Li. SiOC/nSi_a on the contrary, demonstrates a stable cycling performance for up to 100 cycles. This excellent performance is explained by the enhanced matrix integrity of the compound, rationalized by a smaller size of the embedded crystallized Si grains and an intrinsically enhanced electrical conductivity due to the formation of SiC.

Journal or Publication Title: Journal of Power Sources
Volume: 269
Uncontrolled Keywords: Li-ion battery; Anode; Silicon oxycarbide; SiOC; Nano-silicon; Polymer-derived ceramic
Divisions: 11 Department of Materials and Earth Sciences > Earth Science > Geo-Material-Science
11 Department of Materials and Earth Sciences > Material Science > Dispersive Solids
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > A - Synthesis > Subproject A4: Novel functional ceramics using anionic substitution in oxidic systems
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > B - Characterisation > Subproject B3: Structure Characterization of Piezoelectric Ceramics With Respect to Electrical Fatigue
11 Department of Materials and Earth Sciences > Earth Science
11 Department of Materials and Earth Sciences > Material Science
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > A - Synthesis
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > B - Characterisation
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue
11 Department of Materials and Earth Sciences
Zentrale Einrichtungen
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
DFG-Collaborative Research Centres (incl. Transregio)
Date Deposited: 18 Jul 2014 09:50
Official URL: http://dx.doi.org/10.1016/j.jpowsour.2014.06.089
Additional Information:

SFB 595 Cooperation A4, B3

Identification Number: doi:10.1016/j.jpowsour.2014.06.089
Funders: This work was financially supported by the Deutsche Forschungsgemeinschaft (DFG), Bonn, Germany within the priority program SPP1473/JP8 and the collaborative research center SFB595.
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