Structural characterization of LiMn2−xNixO4 (x = 0 and 0.5) and their dielectric analysis

Recently, the development of cathode materials for lithium-ion batteries that provide high voltage and improved cyclability has advanced to meet the demands for high-power applications. LiMn2O4 spinel is regarded as one of the most promising cathode materials, it is considered to be attractive due to its low cost, environmental friendliness and good safety. In the present study, we have synthesized a pure LiMn2O4 and nickel doped spinel structure LiMn1.5Ni0.5O4 cathode material by the sol-gel combustion method using citric acid as the chelating agent. The structural identification, surface morphology and dielectric studies of the synthesized cathode materials are studied by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), electron spin resonance (ESR) and impedance spectroscopy. The XRD analysis shows that both samples exhibit the cubic spinel phase with the space group Fd3¯m. The SEM study reveals that LiMn2−xNixO4 (x = 0 and 0.5) have a fairly uniform grain size distribution throughout the samples. Also, we examined the arrangement of Mn/Ni ions within the lattice for both the compounds using FT-IR spectra. The paramagnetic behavior of the synthesized compounds is determined using ESR studies. The impedance and dielectric analysis of the LiMn2−xNixO4 (x = 0 and 0.5) samples were measured at room temperature. The LiMn1.5Ni0.5O4 compound shows a higher reversible capacity and relatively good rate behavior compared to LiMn2O4.