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Table sugar as preparation and carbon coating reagent for facile synthesis and coating of rod-shaped MnO2

Hashem, Ahmed M. and Abuzeid, Hanaa M. and Nikolowski, Kristian and Ehrenberg, Helmut (2010):
Table sugar as preparation and carbon coating reagent for facile synthesis and coating of rod-shaped MnO2.
In: Journal of Alloys and Compounds, pp. 300-303, 497, (1-2), ISSN 09258388, [Online-Edition: http://dx.doi.org/10.1016/j.jallcom.2010.03.039],
[Article]

Abstract

Rod-shaped α-MnO2 has been synthesized by a novel and facile wet chemical method using simple sugar and potassium permanganate. Redox reaction between KMnO4 and sucrose is carried out in an acidic medium. Acidic medium provides a reducing character to sucrose through its decomposition to elemental carbon. Carbon coating process was done using simple sugar also as a source for carbon in an absolute ethanol with heating the mixture of α-MnO2 and sugar at 350 °C for an hour in an ambient atmosphere. A single phase of cryptomelane-like phase MnO2 was observed from XRD patterns for bare and carbon coated samples. TGA analysis shows the presence of carbon layer through more weight loss percent of carbon coated sample in comparison with that of carbon free MnO2. Both virgin and carbon coated MnO2 have high thermal stability due to high percent of K inside the tunnel determined from ICP analysis. Transmission Electron Microscope (TEM) showed a rod-shaped crystal for both the parent and carbon coated α-MnO2 and confirmed the presence of a thin film of carbon around MnO2 particles. Both XRD and TEM investigations show that the prepared powders are in nano-scale. Initial capacity of about 140 mAh/g was obtained for the parent and carbon coated samples. The results show also that carbon coating process improves the capacity retention and the efficiency of α-MnO2 in comparison with that carbon free sample.

Item Type: Article
Erschienen: 2010
Creators: Hashem, Ahmed M. and Abuzeid, Hanaa M. and Nikolowski, Kristian and Ehrenberg, Helmut
Title: Table sugar as preparation and carbon coating reagent for facile synthesis and coating of rod-shaped MnO2
Language: English
Abstract:

Rod-shaped α-MnO2 has been synthesized by a novel and facile wet chemical method using simple sugar and potassium permanganate. Redox reaction between KMnO4 and sucrose is carried out in an acidic medium. Acidic medium provides a reducing character to sucrose through its decomposition to elemental carbon. Carbon coating process was done using simple sugar also as a source for carbon in an absolute ethanol with heating the mixture of α-MnO2 and sugar at 350 °C for an hour in an ambient atmosphere. A single phase of cryptomelane-like phase MnO2 was observed from XRD patterns for bare and carbon coated samples. TGA analysis shows the presence of carbon layer through more weight loss percent of carbon coated sample in comparison with that of carbon free MnO2. Both virgin and carbon coated MnO2 have high thermal stability due to high percent of K inside the tunnel determined from ICP analysis. Transmission Electron Microscope (TEM) showed a rod-shaped crystal for both the parent and carbon coated α-MnO2 and confirmed the presence of a thin film of carbon around MnO2 particles. Both XRD and TEM investigations show that the prepared powders are in nano-scale. Initial capacity of about 140 mAh/g was obtained for the parent and carbon coated samples. The results show also that carbon coating process improves the capacity retention and the efficiency of α-MnO2 in comparison with that carbon free sample.

Journal or Publication Title: Journal of Alloys and Compounds
Volume: 497
Number: 1-2
Uncontrolled Keywords: α-MnO2; Carbon coating; Li-batteries
Divisions: DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > B - Characterisation > Subproject B4: In situ investigations of the degradation of intercalation batteries and their modelling
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
Zentrale Einrichtungen
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
DFG-Collaborative Research Centres (incl. Transregio)
Date Deposited: 15 Aug 2011 09:15
Official URL: http://dx.doi.org/10.1016/j.jallcom.2010.03.039
Additional Information:

SFB 595 B4

Identification Number: doi:10.1016/j.jallcom.2010.03.039
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