Structural and Morphological Studies of Two-Step Synthesized LiCoO2 and Microwave Synthesized LiFePO4 Particles

Abstract

ABSTRACT Crystalline dispersible LiCoO2 nanoparticles were synthesized by a rapid two-step method. In the first step, Co3O4 nanoparticles were obtained by facile microwave assisted hydrothermal method. In the second step, the as-sy nthesiz ed Co 3O4 nanoparticles were transformed into LiCoO2 nanoparticles through solid-state reaction method. Olivine LiFePO4 with spindle like microstructure was prepared by rapid microwave assisted hydrothermal method within short time at 140°C. The synthesized samples were characterized by X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM ) and energy dispersive X-ray spectroscopy (EDX). The XRD reflection peaks revealed that the synthesized LiCoO2 belongs to R-3m space group with hexagonal crystal structure. No impurity phase of Co3O4 was detected in LiCoO2 after calcination at 750°C for 1 h. Powder XRD results also authenticated the formation of LiFePO4 phase with orthorhombic crystal structure. FTIR analysis revealed the structural co-ordination of the prepared L iF ePO4 particles. SEM analysis showed the formation of monodispersed LiCoO2 nanoparticles with spherical particle morphology. For LiFePO4, SEM analysis revealed the formation of porous spindle like microstructure, composed of densely packed secondary nanoflakes. Further, EDX spectra of the samples confirmed the presence of corresponding elements in the synthesized samples. GRAPHICAL ABSTRACT