Structure and Dielectric Studies of LiNi0.92Mg0.02 (M) 0.06O2 (M = Co and Zn) Cathode Materials for Lithium-Ion Batteries

Abstract

At present, the promising cathode materials for lithium ion batteries are layered structure LiCoO 2 and LiNiO 2. The LiCoO 2 (LiNiO 2) have some disadvantages due to structural instability at high temperatures. In the present paper, we discuss the effect of Co, Zn and Mg substitution in LiNiO 2 for cathode materials on structural and electrical properties. The layered structure LiNi 0.92 Mg 0.02 (M) 0.06 O 2 (M = Co and Zn) cathode materials were synthesized by the solid state reaction method at high temperature. The materials were systematically characterized by TG/DTA, XRD, FESEM, FT-IR and electrical impedance spectroscopy (EIS) studies. The synthesized material has configuration temperature is confirmed from thermogravimetry by differential thermal analysis. All the characterizations show that the cathode materials with their Ni compound substituted by Co, Zn and Mg keep a typical α-NaFeO 2 layered structure with 3 R m space group. The FESEM reveals that the particle size of the samples is about 2 to 4 µm. The local cation (Li-O) of the materials is understood from Fourier transform infrared spectroscopy (FT-IR) studies. The electrical conductivity is calculated from the synthesized sample Co content it is found to be 9.26x10-6 S cm-1 at 110 °C temperature is compared to Zn content. The dielectric constant studies are also discussed through impedance spectroscopy.