Influence of citrate/nitrate ratio on the preparation of Li0.5La0.5TiO3 nanopowder by combustion method

Preparation of nano-crystalline Li0.5La0.5TiO3 perovskite material using citrate–nitrate redox reaction by the combustion technique is reported. The role of the ammonium nitrate concentration used to co-precipitate the Li0.5La0.5Ti-citrate precursor is revealed by ATD/TG, XRD, SEM-EDX and HRTEM techniques. Thermo-gravimetric analysis data show how the intensity of the exothermic peak associated with the citrate–nitrate redox reaction decreases until disappearance as the citrate/nitrate molar ratio increases. The XRD study indicates that a single-phase cubic Li0.5La0.5TiO3 phase is formed at 350°C when the citrate/nitrate ratio varies between 0.13 and 0.17. The formed Li0.5La0.5TiO3 powders show an average particle size of 15–20nm. Electrochemical impedance spectroscopy technique reveals a relative high ionic conductivity inside the grain for the nanometric Li0.5La0.5TiO3 material, with values of around 10−4S/cm at room temperature.