Effect of vacancies and vanadium doping on the structural and magnetic properties of nano LiFe<inf>2.5</inf>O<inf>4</inf>

Abstract

Nano LiFe2.5-xVxO4 and LiFe2.5-1.667xVxO4 systems were prepared by a sol–gel procedure at low temperatures. The influence of vacancies and vanadium doping on the structure parameters; lattice parameter, cation distribution, crystallite size, dislocation density, intrinsic distances, and bond angles between different cations and anions was fully studied by x-ray diffraction analysis applying Rietveld method. The nano nature and the particles morphology of the formed samples were examined by the transmission electron microscope. The change and the splitting, upon doping, of vibration bands obtained by Fourier-transform infrared spectroscopy were discussed. Magnetic measurements manifested that all samples exhibited a superparamagnetic behavior with a single domain characteristic. The change of saturation magnetization (Ms) and remnant magnetization (Mr) was correlated with the change in the crystallite size, and the cation distribution of different ions between different sites. The high concentrations of vacancies presented due to doping with vanadium ions is enhancing the electrochemical charge–storage properties of the samples making them a good potential electrode for Li-ion batteries.