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Issue 45, 2005
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Structural and electrochemical properties of new nanospherical manganese oxides for lithium batteries

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Abstract

The products of decomposition of manganese carbonate with and without doping by copper or cobalt, at temperatures <500 °C in air were studied. Doped systems with 20 atom% Cu or Co give new nanometric manganese oxides agglomerated in submicronic spheres at 370 °C. Transmission electron microscopy (TEM) shows that these X-ray amorphous compounds are nanocrystalline with grain size in the 10 nm range and a spinel substructure. The electrochemical behaviour of these materials in lithium cells was studied. Whereas non-doped manganese oxide exhibits poor intercalation capabilities, the freshly co-precipitated Cu or Co doped materials can be cycled successfully around 3 V vs. Li/Li+. Step-potential electrochemical spectroscopy shows that the initial discharge gives rise to a two-phase transition and is followed by stable, reversible, single-phase cycling. Best results are obtained on a cobalt-doped manganese oxide (Co : Mn = 1 : 5), which can sustain more than 100 charge–discharge cycles with a 175 mA h g−1 capacity in the 1.8–4.2 V range. XAS spectra were measured on pristine and electrochemically discharged materials, showing that (1) in the cobalt-doped material, cobalt is divalent and manganese is the only redox-active species, (2) the variations in local structure around Mn on discharge are much smaller than in long-range ordered compounds such as Li–Mn–O spinels.

Graphical abstract: Structural and electrochemical properties of new nanospherical manganese oxides for lithium batteries

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Article information


Submitted
29 Jun 2005
Accepted
16 Sep 2005
First published
03 Oct 2005

J. Mater. Chem., 2005,15, 4799-4808
Article type
Paper

Structural and electrochemical properties of new nanospherical manganese oxides for lithium batteries

P. Strobel, F. Thiéry, C. Darie, O. Proux, A. Ibarra-Palos, M. Bacia and J. B. Soupart, J. Mater. Chem., 2005, 15, 4799
DOI: 10.1039/B509210H

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