Effect of lithium doping on frequency-dependent dielectric properties of manganese ferrite nanoparticles

For enhancing the charge storage of nanoparticles by modifying the grains, a novel lithium-doped iron-based nanoparticle (Li2xMn1-xFe2O4) was designed and synthesized. Lithium-doped manganese ferrite (Li2xMn1-xFe2O4) nanoparticles were prepared using sol-gel route with different doping concentrations of lithium, i.e., x = 0, 0.25, 0.50, 0.75, and 1.0 when annealed at 500 degrees C temperature. The structure (crystal structure and crystallite size), vibrational modes (functional groups of molecules), morphology, and composition were investigated and confirmed by X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The vibrational bands shifted towards high wavenumbers due to small ionic radii of Li+1 to Mn+2 which indicated the successful replacement of lithium with manganese in Li2xMn1-xFe2O4 nanoparticles and redistribution of cations between octahedral and tetrahedral sites. Moreover, the dielectric parameters of Li2xMn1-xFe2O4 nanoparticles were investigated using LCR at room temperature. The dielectric parameters revealed improved dielectric properties (epsilon ' 168, epsilon '' 332, tan delta 2.63, and sigma(ac) 3.78 x 10(-4) Omega(-1) m(-1)) with increasing concentrations of lithium in Li2xMn1-xFe2O4 nanoparticles owed to increasing Fe2+ ions at the octahedral sites. Furthermore, these Li2xMn1-xFe2O4 nanoparticles offered large places and provoke more active sites for storage due to their high ac-conductivity. Henceforth, it can be suggested that lithium-doped manganese ferrite nanoparticles can be the best candidate for energy storage devices.