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Void-shell silicon/carbon/SiCN nanostructures: toward stable silicon-based electrodes

Vrankovic, Dragoljub and Reinold, Lukas Mirko and Riedel, Ralf and Graczyk-Zajac, Magdalena (2016):
Void-shell silicon/carbon/SiCN nanostructures: toward stable silicon-based electrodes.
In: Journal of Materials Science, Springer New York, pp. 6051-6061, 51, (12), ISSN 0022-2461,
[Online-Edition: http://dx.doi.org/10.1007/s10853-016-9911-x],
[Article]

Abstract

We present a systematic work to design a void-shell nanostructures for improving the stability of silicon electrodes while alloying with lithium. To enhance the electrical conductivity, silicon is coated with carbon by using a simple and non-hazard route prior to embedding the Si particles in silicon carbonitride (SiCN). An inactive matrix, namely a polymer-derived SiCN ceramic is used to stabilize the composite. Additionally, cavities around silicon to accommodate volume changes are introduced by partial carbon burning. Significant increase in porosity of more than one order of magnitude is found by means of BET measurements for the samples obtained after additional heat treatment in air. TGA coupled with FTIR spectrometry shows that the ceramic matrix is stable upon heating, while burned carbon originates from pyrolyzed fructose. TEM micrographs confirm the presence of carbon/void around silicon particles embedded in the ceramic matrix. Electrochemical investigations reveal an improved conductivity due to the presence of carbon coating. Contribution of silicon in lithium storage is identified, whereas voids introduced around the silicon particles are found to improve cycling stability of silicon.

Item Type: Article
Erschienen: 2016
Creators: Vrankovic, Dragoljub and Reinold, Lukas Mirko and Riedel, Ralf and Graczyk-Zajac, Magdalena
Title: Void-shell silicon/carbon/SiCN nanostructures: toward stable silicon-based electrodes
Language: English
Abstract:

We present a systematic work to design a void-shell nanostructures for improving the stability of silicon electrodes while alloying with lithium. To enhance the electrical conductivity, silicon is coated with carbon by using a simple and non-hazard route prior to embedding the Si particles in silicon carbonitride (SiCN). An inactive matrix, namely a polymer-derived SiCN ceramic is used to stabilize the composite. Additionally, cavities around silicon to accommodate volume changes are introduced by partial carbon burning. Significant increase in porosity of more than one order of magnitude is found by means of BET measurements for the samples obtained after additional heat treatment in air. TGA coupled with FTIR spectrometry shows that the ceramic matrix is stable upon heating, while burned carbon originates from pyrolyzed fructose. TEM micrographs confirm the presence of carbon/void around silicon particles embedded in the ceramic matrix. Electrochemical investigations reveal an improved conductivity due to the presence of carbon coating. Contribution of silicon in lithium storage is identified, whereas voids introduced around the silicon particles are found to improve cycling stability of silicon.

Journal or Publication Title: Journal of Materials Science
Volume: 51
Number: 12
Publisher: Springer New York
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Dispersive Solids
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 11 Apr 2016 12:02
Official URL: http://dx.doi.org/10.1007/s10853-016-9911-x
Identification Number: doi:10.1007/s10853-016-9911-x
Funders: We gratefully acknowledge the financial support of the German Research Foundation (DFG) SPP1473/ JP8.
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