Structural, Microstructural and Raman spectral studies of LiMn_2-xZn_xO₄ (x = 0.02, 0.12 and 0.22) for Lithium-ion batteries

The LiMn_2-xZn_xO₄ simultaneously doped with Cu has been tried to improve the cathode performance in lithium-ion batteries. In this paper, the layered LiMni_1-xZn_xO₄ (x = 0.02, 0.12 and 0.22) cathodes are synthesized by the sol-gel method at high temperature of 850°C for 8 h. The structural properties of synthesized materials are characterized using the results from X- ray diffraction (XRD), Scanning electron micrograph (SEM), Fourier infrared spectra (FT-IR) and Raman spectroscopic studies. The XRD pattern indicates that the pure spinel cubic structure is of space group Fd-3m. The SEM results show uniform crystallinity and the particle size tends to decrease with increasing Zn content. The FT-IR spectra of the materials are used to explain the vibrational bonding nature. From the Raman Spectroscopy all the peaks observed in doped Zn samples matched with the Raman active modes of crystal structure. The main characteristic peak at 439 cm-1 indicates the spinel structure observed. (paper)