SYNTHESIS, DIELECTRIC AND IMPEDANCE STUDIES OF LiNi1-X-0.02Mg0.02ZnXO2 (X = 0.0 and 0.02) CATHODE MATERIALS FOR LITHIUM-ION BATTERIES.

Zn-Mg co-substituted layered structure cathode materials LiNi1-x-0.02ZnxMg0.02O2 (x = 0.00 and 0.02) is prepared by a solid state reaction method. These materials are characterized by structural, morphological and electrochemical impedance studies. The X-ray diffraction (XRD) data revealed that the formation of phase and possessed the ?-NaFeO2 structure of the rhombohedral-hexagonal system (space group, ) with no evidence of any impurities. The morphology and uniform distribution of the synthesized samples are studied with Field Effect Scanning Electron Microscopy (FESEM). The substitution of Mg and Zn for Ni can enlarge the particle size and improve the crystallinity. Electrochemical impedance studies (EIS) in the frequency range from 42 Hz to 1 MHz with temperature variation from 30° to 100° C are studied by high ionic conductivity for amount of x = 0.02 doping material. The temperature dependent non-Debye type of dielectric relaxation has been studied and the Nyquist plots showed the negative temperature coefficient of resistance behavior of these compounds.