Structural and spectroscopic study of NaSbR(PO₄)₃ (R = Cr, Fe, In) phases

Abstract

Crystallographic structures of the three NaSbR(PO 4 ) 3 (R = Cr, Fe, In) phases were determined at room temperature from X-ray powder diffraction (XRD) data using the Rietveld analysis. The three compounds belong to the Nasicon structural family. The presence of the (303) reflection in all XRD spectra of NaSbR(PO 4 ) 3 shows clearly that all compounds crystallise in rhombohedral system with R 3 space group. Na atoms are practically ordered within the two positions, 3a and 3b, of M1 sites. Structure refinements show also a partially-ordered distribution of Sb 5+ and R 3+ ions within the Nasicon framework. A Raman and Infrared spectroscopic study was used to obtain further structural information about the nature of bonding in NaSbR(PO 4 ) 3 (R = Cr, Fe, In) phases.

Li3V2(PO4)3-coated Li1.17Ni0.2Co0.05Mn0.58O2 as the cathode materials with high rate capability for Lithium ion batteries

“…4a), which are assigned to the asymmetric stretching modes of M-O bonds in MO 6 octahedra and the O-M-O bending modes [32]. For LVP-coated samples (5 wt%), the bands at 1034 cm -1 are attributed to the symmetric non degenerate PO stretching modes (n 1 ) and the bands at 1090 and 1140 cm -1 are attributed to the symmetric, triply degenerate OPO bending modes (n 3 ) in terminal PO 4 units in Nasicon structure respectively [33][34][35][36][37][38]. The bands at 550 cm -1 shifts to lower wavenumber may due to the n 4 modes in PO 4 units.…”