Influence of nickel content on the chemical bonding character of LiMn2−xNixO4 spinel oxides

Versatile Approach Combining Theoretical and Experimental Aspects of Raman Spectroscopy To Investigate Battery Materials: The Case of the LiNi0.5Mn1.5O4 Spinel

“…Experimental and calculated Raman spectra of LNMO family Indeed, several groups have reported Raman spectra with the most intense peak at 509 cm −1 for LNMO synthesized at 800°C, 2,30-32 whereas other groups (including ours) noted the peak at 642 cm −1 as the most intense. 1,9,33,34 It appears that these differences are related to neither the laser wavelength of the Raman spectrometer nor the synthesis temperature, since there is no logical trend in the peak/intensity evolution. To exclude the impact of the synthesis temperature on the particle shape, we synthesized d-LNMO at various temperatures (730 to 900 °C) and evaluated the impact on the Raman spectra (results are displayed in Figure S4) but no differences were observed for the intensity ratio of 509/642 cm −1 peaks.…”

“…8,9 To date, no direct proof 3 of the validity of such pre-cited concept has been given. Proposing a novel methodology and solving such a problem could afford a new dimension to Raman spectroscopy, enabling it to follow the oxidation states of transition metals.…”

Preparation and catalytic activity of nickel–manganese oxide catalysts in the reaction of partial oxidation of methane

“…This Raman feature is assigned as an A 1g mode for regular Mn IV O 6 octahedra [20]. This band might, then, correspond to the manganese in the ilmenite structure as this band was absent from the Raman spectra of the solids calcined at 900 C, this band is more intense in the solid prepared via the coprecipitation method which indicates that the ilmenite is more important in this solid than in the solid prepared via solegel method.…”

“…In spinel oxides and in other manganese oxides energies of 600e650 cm À1 are characteristic of vibrations involving motion of oxygens inside the octahedral unit MnO 6 [20]. The broadening of this peak in the direction of lower energies corresponds to a spinel with disordered cationic occupation (inverted spinel) [21].…”

Effects of synthesis temperature and precursor composition on the crystal structure, morphology, and electrode activity of 1D nanostructured manganese oxides

“…1. All the precursor compounds show typical XRD patterns of cubic spinel lattice [1,14,16]. There is no Bragg reflection corresponding to impurity phase like Cr 2 O 3 , indicating .…”