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Phase stability and homogeneity in undoped and Mn‐doped LiFePO 4 under laser heating
Author(s) -
Galinetto Pietro,
Mozzati Maria Cristina,
Grandi Marco Simone,
Bini Marcella,
Capsoni Doretta,
Ferrari Stefania,
Massarotti Vincenzo
Publication year - 2010
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.2558
Subject(s) - maghemite , raman spectroscopy , homogeneity (statistics) , materials science , thermal stability , hematite , impurity , doping , magnetite , analytical chemistry (journal) , hydrothermal circulation , phase (matter) , mineralogy , chemical engineering , chemistry , optics , metallurgy , chromatography , optoelectronics , statistics , physics , mathematics , organic chemistry , engineering
Thermal stability and phase homogeneity of the triphylite LiFePO 4 compound were investigated by means of Raman spectroscopy. A detailed check of phase homogeneity of undoped samples obtained from different preparation routes—hydrothermal, sol–gel, and solid state synthesis—and Mn‐doped compounds from solid‐state synthesis was performed by means of a mapping of the Raman spectra. The triphylite compositional and structural properties were carefully investigated also with the help of structural refinements and magnetic techniques, which also allowed us to reveal and identify the impurity phases formed together with the olivine LiFePO 4 . The effect of laser irradiation on the triphylite thermal stability was thoroughly investigated and related to the synthesis route, to the doping, and to the sample homogeneity. The thermal stability of iron oxides, present both as synthesis products and as consequence of the irradiation itself, was also analyzed following the magnetite→maghemite→hematite phase transformation. All the experimental observations concur in indicating that the effectiveness of the laser heating on these compounds mainly depends on grain size and the degree of order of the olivine structure, the highest thermal stability being displayed in the case of the nonhomogenous undoped samples obtained from solid‐state preparation, which show a highly ordered triphylite phase. Copyright © 2010 John Wiley & Sons, Ltd.