Synthesis of Cr doped LiMnPO₄ cathode materials and investigation of their dielectric properties

Lithium manganese phosphate (LiMnPO₄) and a series of chromium-doped lithium manganese phosphate with variation in Cr content LiCr_xMn_1−xPO₄ (x = 0.03, 0.06, 0.1) were prepared via conventional sol-gel method and their dielectric properties have been explored as a function of frequency. The structure and morphology were investigated by X-ray diffraction technique (XRD), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. The influence of frequency upon electrical conductivity as well as di-electric properties of the as-synthesized LiCr_xMn_1−xPO₄ materials have been analyzed by dielectric parameters and AC conductivity using impedance analyzer. It was observed that dielectric constant increased with frequency at lower chromium concentration while at higher chromium contents, the dielectric constant was decreased with increasing frequency. Hence, the composition with highest Cr content (ie, x = 0.1) is proved as best material for various applications owing to its lowest AC-conductivity and lowest dielectric loss. Therefore, it is revealed that chromium doping is quite advantageous for performance of LiMnPO₄ in device applications as Cr doped LiMnPO₄ unveiled improved dielectric loss.