Investigation of intrinsic electrical properties of cerium doped lithium cobalt oxide, nanostructured materials

Abstract

Cerium doped lithium cobalt oxide LiCo1−xCexO2 (0≤x≤0.08) compositions have been synthesized by a modified ‘Pechini’ process. The structural and electrical properties of the doped compositions were investigated through XRD, FTIR, EDX, Raman, and (EIS) experiments. X-Ray Diffraction (XRD) analysis established the formation of single phase crystalline nature of the synthesized powders. Ce doped samples crystallized in the R3m space group, with expansion along the ‘c’ lattice. Whereas scanning electron microscopic (SEM) analysis revealed that due to Ce doping the microstructure has altogether changed, with the presence of grains and grain boundaries. Raman and FTIR (Fourier transform infra-red) studies assisted to attribute ordered crystalline realms within the lattice. Energy Dispersive X-ray (EDX) confirmed the presence of no additional peak thus ruling out the presence of impurities. In order to discover the effects of the altered microstructure and existence of the crystalline domains on the resistive and dielectric properties all the compositions were exposed to EIS (electrical impedance spectroscopy) study at room temperature and in wide frequency range. Electrical properties demonstrated that LiCo1−xCexO2 (x = 0.04 and 0.06) had more resistance in comparison to x = 0 and 0.08 compositions. According to crystal field splitting theory, incoming electron from the doped metal created an insulating phase responsible for the enhanced resistance. Modified Debye behavior was exhibited by frequency dependent dielectric measurements at room temperature. As a result of tailored properties LiCo1−xCexO2 compositions can be used in high frequency devices.