LiCoO2 CERAMICS POWDERS DOPED WITH EUROPIUM

Abstract

Lithium cobaltate (LiCoO2) is one of the materials used to make cathodes for lithium-ion batteries. However, it is subject to various limitations, such as structural and thermal instability, low electrochemical capacity, irreversibility, and insecurity. Newer materials are designed and produced with rare earths a low concentration, to promote the better electrochemical performance of lithium-ion batteries. The europium ion (Eu3+) has advantageous properties, such as an ionic radius that is larger than the radii of lithium and cobalt, and thermomechanical and structural stability. In this paper, is reported on the production of crystalline lithium cobaltate (LiCoO2) powders doped with Eu3+ at different concentrations (0.01, 0.03, and 0.05 mol %). There are various methods for producing these powders, such as the solid-state, hydrothermal, and sol gel methods, among others. However, the sol-gel method makes it possible to obtain crystalline materials at low residence temperatures, to control variables during synthesis, and to produce materials of high purity at nanometric sizes. The materials obtained were analyzed by various characterization techniques such as, IR spectroscopy (FTIR), x-ray diffraction (XDR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM)  to determine the morphological and compositional properties after doping with Eu3+. Structural analysis and Rietveld refinement showed a hexagonal structure at 800 °C, with planes attributable to the R-3m space group. By means of FTIR, bands characteristic of LiCoO2 and the band corresponding to Eu3+ were observed. When the Eu3+ ion was added at different concentrations, the morphology of the particles was uniform and quasispherical. The elements were identified by EDS as cobalt and europium. Through TEM, the interplanar distance of the main plane of LiCoO2 doped with Eu3+ were obtained, that is, (003) and an increase in the plane took place when the Eu3+ was incorporated ion into the crystalline structure.