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Manganese Dioxides: Structural Model and In-Situ Neutron Powder Diffraction Investigation of Thermal Annealing and Electrochemical Reduction‡

Published online by Cambridge University Press:  28 February 2011

M. Ripert ,
J. Pannetier ,
Y. Chabre  and
C. Poinsignon
M. Ripert
Affiliation:
Institut Laue-Langevin, 156X, 38042 Grenoble, France Laboratoire d'Ionique et d'Electrochimie du Solide, INP Grenoble BP 75, 38402 Saint Martin d'Hères, France
J. Pannetier
Affiliation:
Institut Laue-Langevin, 156X, 38042 Grenoble, France
Y. Chabre
Affiliation:
Laboratoire de Spectrométrie Physique, Université Joseph Fourier, BP 87, 38402 Saint Martin d'Hères, France
C. Poinsignon
Affiliation:
Laboratoire d'Ionique et d'Electrochimie du Solide, INP Grenoble BP 75, 38402 Saint Martin d'Hères, France
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Abstract

Starting from the seminal work of De Wolff [1], we have developed a structural description, based on two kinds of defects, which accounts for the scattering function of all γand ε-MnO2. Using numerical simulation results, we propose simple methods to estimate the parameters which characterize real manganese dioxide samples. Real time neutron powder diffraction has been used to investigate in situ the transformations undergone by γ-MnO2 during thermal annealing and electrochemical reduction in alkaline solutions. We have found that thermally induced transformation from MnO2 to ∝-Mn2O3 can involve up to seven different steps and that electrochemical reduction of γ-MnO2 in KOD electrolyte proceeds through three stages, the final one leading in most cases to a breakdown of the initial crystal lattice.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 210: Symposium L – Solid State Ionics II , 1990 , 359
Copyright
Copyright © Materials Research Society 1991

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Footnotes

‡

Work supported by the PIRSEM/CNRS (ARC-IPROM)

References

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