Structural, electrical, and dielectric properties of nickel-doped spinel LiMn2O4 nanorods

Abstract

Spinel pure and Ni-doped LiMn2O4 nanorods were synthesized by a rapid microwave-assisted hydrothermal process followed by a solid-state reaction method. Their structural, morphological, electrical, and dielectric properties were investigated by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, transmission electron microscopy (TEM), and impedance spectroscopy techniques. Powder XRD studies revealed that all the synthesized samples have well-defined cubic crystal structure and the Ni2+ doping in manganese sites did not affect spinel LiMn2O4 structure. TEM images of pure and Ni-doped LiMn2O4 samples clearly showed the formation of well-dispersed nanorods with uniform distribution. The Ni2+ doping did not affect the nanorod morphology of pure LiMn2O4. The spinel LiMn2O4 nanorods showed an electrical conductivity of 3.13 × 10−4 S cm−1, at room temperature. The A.C conductivity studies revealed that the pure and Ni-doped LiMn2O4 nanorods obey Jonscher’s power law. The dielectric studies revealed that the dielectric constant of the samples decreases with frequency, which is due to decrease in charge accumulation at the interface.