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Study of the spectro‐chemical signatures of cobalt–manganese layered oxides (asbolane–lithiophorite and their intermediates) by Raman spectroscopy
Author(s) -
Burlet C.,
Vanbrabant Y.
Publication year - 2015
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.4755
Subject(s) - raman spectroscopy , manganese , chemistry , analytical chemistry (journal) , diffraction , cobalt , spectroscopy , raman scattering , oxide , full width at half maximum , materials science , inorganic chemistry , optics , physics , optoelectronics , organic chemistry , chromatography , quantum mechanics
In this study, Raman microspectroscopy is applied to investigate two manganese oxide phases: lithiophorite [(Al,Li)Mn 4+ O 2 (OH) 2 ] and asbolane [(Ni,Co) x Mn 4+ (O,OH) 4 ·nH 2 O], along with their intermediates (‘asbolane–lithiophorite intermediates’: ALI). These oxides typically incorporate variable concentrations of Co, Ni, Cu and Li. They represent a group of economically interesting phases that are difficult to identify and characterize with classical X‐ray diffraction techniques. We show that Raman micro spectroscopy is useful to the investigation of those phases, but they require to be tested in very low laser power conditions to avoid sample degradation (e.g. 0.2 mW with λ = 532 nm). We propose reference Raman spectroscopic signatures for lithiophorite, asbolane and ALI phases. These spectra are mainly composed of two spectral domains, the first one is located between 370 and 630 cm −1 and the second one between 900 and 1300 cm −1 . We then assess the impact of their highly variable chemistry on their Raman peak positions, intensities and FWHM using a semi‐systematic curve‐fitting method profiled for these phases. Copyright © 2015 John Wiley & Sons, Ltd.