Raman scattering intensity on LiNi1−xCoxPO4 series orthophosphates

Herein, a series of cobalt-doped LiNi_1−xCo_xPO₄ orthophosphates (with a step of 0.1 in Co concentration x) were synthesized using the glycerol–nitrate method. X-ray photoelectron spectroscopy (XPS), X-ray diffraction, and Raman scattering were employed to investigate the crystalline structure of the synthesized LiNi_1−xCo_xPO₄ samples (x = 0.6, 0.7, 0.8, 0.9, and 1). Substitution of Ni²⁺ ions by Co²⁺ results in an increase in unit cell volume, longer interatomic distances, and weaker P–O and M–O bonds. A clear dependence of Raman scattering intensity on the cobalt concentration x was observed. The wide-scan XPS spectra confirm the presence of only Li, P, C, O, Ni, and Co elements, with no detectable impurities. Based on our findings, an effective strategy can be proposed to elucidate the fundamental relationship between the structure and chemistry of these materials and their resulting physical properties.