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Influence of the microstructure and its stability on the electrochemical properties of EMD produced from a range of precursors

Biswal, A., Tripathy, B. C., Sanjay, K., Meyrick, D., Subbaiah, T and Minakshi, M. (2013) Influence of the microstructure and its stability on the electrochemical properties of EMD produced from a range of precursors. Journal of Solid State Electrochemistry, 17 (12). pp. 3191-3198.

Link to Published Version: http://dx.doi.org/10.1007/s10008-013-2231-z
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Abstract

The influence of the microstructure and the stable crystal structure on the electrochemical properties of the electrolytic manganese dioxide (EMD) produced from manganese cake (EMDMC), low-grade manganese ore (EMDLMO), and synthetic manganese sulfate solutions (EMDSMS) is reported. X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry/differential thermal analysis, field emission scanning electron microscopy (FESEM), and chemical analyses were used to determine the structural and chemical characteristics of the EMD samples. The charge-discharge profile was studied in 9 M KOH using a galvanostatic charge-discharge unit. All the samples were found to contain predominantly γ-phase MnO2, which is electrochemically active for energy storage applications. FESEM images show that preparation method significantly influences surface morphology, shape, and size of the EMD particles. In almost all cases, nanoparticles were obtained, with spindle-shaped nanoparticles for EMDMC, platy nanoparticles in the case of EMDLMO, and anisotropic growth of tetra-branched star-like nanoparticles of EMDSMS. These nanoparticles arrange themselves in a near net-like fashion, resulting in porosity of the flakes of EMD during electrochemical deposition. Thermal studies showed loss of structural water and formation of lower manganese oxides. The EMDMC showed superior discharge capacity of ~280 mAh g-1 as compared to EMDLMO (275 mAh g-1) and EMDSMS (245 mAh g-1).

Publication Type: Journal Article
Murdoch Affiliation: School of Chemical and Mathematical Science
School of Veterinary and Life Sciences
Publisher: Springer Verlag
Copyright: © 2013 Springer-Verlag Berlin Heidelberg
URI: http://researchrepository.murdoch.edu.au/id/eprint/17847
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