TU Darmstadt / ULB / TUbiblio

Synthesis, structure, magnetic, electrical and electrochemical properties of Al, Cu and Mg doped MnO2

Hashem, Ahmed M. and Abuzeid, Hanaa M. and Narayanan, N. and Ehrenberg, Helmut and Julien, C. M. (2011):
Synthesis, structure, magnetic, electrical and electrochemical properties of Al, Cu and Mg doped MnO2.
In: Materials Chemistry and Physics, pp. 33-38, 130, (1-2), ISSN 02540584, [Online-Edition: http://dx.doi.org/10.1016/j.matchemphys.2011.04.074],
[Article]

Abstract

Pure and doped manganese dioxides were prepared by wet-chemical method using fumaric acid and potassium permanganate as raw materials. X-ray diffraction patterns show that pure and Al, Cu and Mg doped manganese dioxides (d-MnO2) crystallized in the cryptomelane-MnO2 structure. Thermal analysis show that, with the assistance of potassium ions inside the 2 × 2 tunnel, the presence of Al, Cu and Mg doping elements increases the thermal stability of d-MnO2. The electrical conductivity of d-MnO2 increases in comparison with pure MnO2, while Al-doped MnO2 exhibits the lower resistivity. As shown in the magnetic measurements, the value of the experimental effective magnetic moment of Mn ions decreases with introduction of dopants, which is attributed to the presence of a mixed valency of high-spin state Mn4+/Mn3+. Doped MnO2 materials show good capacity retention in comparison with virgin MnO2. Al-doped MnO2 shows the best electrochemical results in terms of capacity retention and recharge efficiency.

Item Type: Article
Erschienen: 2011
Creators: Hashem, Ahmed M. and Abuzeid, Hanaa M. and Narayanan, N. and Ehrenberg, Helmut and Julien, C. M.
Title: Synthesis, structure, magnetic, electrical and electrochemical properties of Al, Cu and Mg doped MnO2
Language: English
Abstract:

Pure and doped manganese dioxides were prepared by wet-chemical method using fumaric acid and potassium permanganate as raw materials. X-ray diffraction patterns show that pure and Al, Cu and Mg doped manganese dioxides (d-MnO2) crystallized in the cryptomelane-MnO2 structure. Thermal analysis show that, with the assistance of potassium ions inside the 2 × 2 tunnel, the presence of Al, Cu and Mg doping elements increases the thermal stability of d-MnO2. The electrical conductivity of d-MnO2 increases in comparison with pure MnO2, while Al-doped MnO2 exhibits the lower resistivity. As shown in the magnetic measurements, the value of the experimental effective magnetic moment of Mn ions decreases with introduction of dopants, which is attributed to the presence of a mixed valency of high-spin state Mn4+/Mn3+. Doped MnO2 materials show good capacity retention in comparison with virgin MnO2. Al-doped MnO2 shows the best electrochemical results in terms of capacity retention and recharge efficiency.

Journal or Publication Title: Materials Chemistry and Physics
Volume: 130
Number: 1-2
Uncontrolled Keywords: Manganese oxides; Sol–gel growth; Magnetic properties; Conductivity; Galvanometry measurements
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 Sep 2011 14:17
Official URL: http://dx.doi.org/10.1016/j.matchemphys.2011.04.074
Additional Information:

SFB 595 B4

Identification Number: doi:10.1016/j.matchemphys.2011.04.074
Export:

Optionen (nur für Redakteure)

View Item View Item