Synthesis of nanocrystalline Li4Ti5O12 by a novel aqueous combustion technique

Lithium titanate (Li4Ti5O12) powder has been synthesized by a novel aqueous combustion process using a common amino acid alanine, as fuel. Thermogravimetric analysis of the gel indicates sharp single step combustion at ∼200 °C where nearly 80% weight loss occurs. X-ray analysis shows that the as-synthesized powder contains mostly spinel Li4Ti5O12 phase along with anatase TiO2. About 90% phase purity is obtained when calcined at 800 °C in air. Observation under a Field Emission Scanning Electron Microscope reveals spherical shaped particles with uniform morphology. The particle size as estimated from the micrograph is in the range 40–80 nm. Fourier transformed infrared spectroscopy shows the characteristics bands of Li4Ti5O12 at 652 and 462 cm−1 even in the as-synthesized powder. A wide optical band gap of 1.80 eV has been determined from UV–vis spectroscopy.