Monoclinic β-Li₂TiO₃ nanocrystalline particles employing novel urea assisted solid state route: Synthesis, characterization and sintering behavior

Pure phase monoclinic nano-crystalline Li₂TiO₃ powder was synthesized by a novel urea assisted solid state synthesis method using readily available and economical precursors. A single phase and well crystalline Li₂TiO₃ powder has been obtained at slightly lower temperature (600–700 °C) and shorter duration (2 h) as compared to the conventional solid state method. The proposed method has significant advantages in comparison to other viable methods mainly in terms of phase purity, powder properties and sinterability. Analysis of chemical composition using inductively coupled plasma atomic emission spectroscopy (ICP-AES) shows no loss of lithium from Li₂TiO₃ in the proposed method. The emergence of monoclinic Li₂TiO₃ phase was confirmed by X-ray diffraction (XRD) pattern of as-synthesized powder. The crystallite size of Li₂TiO₃ powder was calculated to be in the range of 15–80 nm, which varied as a function of urea composition and temperature. The morphology of as-prepared Li₂TiO₃ powders was examined by scanning electron microscope (SEM). The effect of urea composition on phase and morphology was investigated so as to delineate the role of urea. Upon sintering at < 1000 °C temperature, the Li₂TiO₃ powder compact attained about 98% of the theoretical density with fine grained (grain size: 2–3 μm) microstructure. It indicates excellent sinter-ability of Li₂TiO₃ powder synthesized by the proposed method. The fine grained structure is desirable for better tritium breeding performance of Li₂TiO₃. Electrochemical impedance spectroscopy at variable temperature showed good electrical properties of Li₂TiO₃. The proposed method is simple, anticipated to be cost effective and convenient to realise for large scale production of phase pure nanocrystalline and having significantly enhanced sinter-ability Li₂TiO₃ powder.