Synthesis and Structural evaluation of Mg, Cu, Zn tri-doped lithium titanium oxide electrode materials for use in lithium ion battery

Abstract

Mg, Cu and Zn metals have been used to tri-dope into the tetrahedral and octahedral sites of Li₄Ti₅O₁₂ (LTO) electrode materials usually used in Li-ion battery. Li_4-xMg_xTi_5-yZn_y/2Cu_y/2O₁₂ (i. x = 0, y = 0 ii. x = 0.05, y=0.10 iii. x= 0.10, y= 0.20 iv. x= 0.15, y= 0.20) materials were synthesized by solid state reaction using the stoichiometric amount of raw materials. The structural and morphological characteristics of the tri-doped Li_4-xMg_xTi_5-yZn_y/2Cuy/2O₁₂ materials were methodically analyzed by using Fourier transform infrared spectroscopy (FT-IR), UV-visible spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopic (SEM) techniques. The results of infrared spectroscopy exhibit bands of TO₆ octahedra and Ti-O-Ti vibrations. Band gap energy calculation from UV-visible spectroscopy demonstrates a critical point of doping. Beyond this point band gap energy has been found to increase upon tri-doping. It has been observed from SEM images that all samples possess micro-porous and coral shape structures. The XRD patterns demonstrate that Mg, Cu and Zn metals tri-doped Li_4-xMg_xTi_5-yZn_y/2Cu_y/2O₁₂ materials have spinel structure as well as good crystallinity.

Journal of Engineering Science 11(1), 2020, 01-08