STUDY OF THERMAL, STRUCTURAL AND ELECTROCHEMICAL PROPERTIES OF SPINEL CATHODE MATERIALS FOR LITHIUM ION BATTERIES

Abstract

In this study, spinel LiMn2O4, Li1.025(Mn1.95Ni0.025Fe0.025)O4 and Li1.025(Mn1.9Ni0.025Fe0.05)O4 cathode materials were effectively synthesized by two steps solid state reaction method. The thermal, structural and electrochemical properties of thesecathode materials were characterized by Thermogravimetric and Differential thermogravimetric analysis (TGA/DTA),x-ray powder diffraction (XRD), scanning electron microscope (SEM), Fouriertransform infrared spectroscopy (FT-IR) and Galvanostatic charge/discharge Test (GCDT).TGA/DTA analysis confirmed that 800 o C is the appropriate temperature for synthesizing LiMn2O4, Li1.025(Mn1.95Ni0.025Fe0.025)O4 and Li1.025(Mn1.9Ni0.025Fe0.05)O4 cathode materials using Li2CO3, Fe2O3, MnO2 and NiO precursors.The XRD analysis reveals that all synthesized spinel cathode materials are in cubic spinel structure with Fd-3m space group. From obtained XRD data, different structural parameters are also `suggested. To examine the surface morphology of the pure and doped LiMn2O4, SEM was used. From the FT-IR study of the material, two distinct strong absorption peaks are identified in the wavenumber region of512 cm -1 to 621 cm -1 .The room temperature the discharge specific capacity of all cathode materials,for LiMn2O4, Li1.025(Mn1.95Ni0.025Fe0.025)O4 and Li1.025(Mn1.9Ni0.025Fe0.05)O4 were found to be 96.4mAh/g, 108.4mAh/gand 112 mAh/g respectively.