Facile synthesis of nanosized Li4Ti5O12 in supercritical water

The high rate capability of lithium titanate (Li4Ti5O12, LTO) is prepared using supercritical hydrothermal synthesis (SHS). The particle size, morphology, crystalline structure and electrochemical properties are analyzed and compared to the properties of LTO particles prepared using a typical solid-state method (SS). Nanosized LTO particles having a high crystallinity are produced in a very short reaction time (15 min) and with subsequent calcination at a low temperature (700 °C) or it can be produced in 6 h without calcination. The size of SHS particles is much smaller (20–200 nm, BET surface area of 10–38 m2 g−1) than that of the SS particles (micron size, BET surface area of 5.4 m2 g−1). The SHS LTO particles are highly phase-pure while the SS particles have impurity phases such as anatase TiO2, rutile TiO2 and Li2TiO3. The SHS LTO show higher initial discharge capacity (212 mAhg−1) and better cycling stability compared to those of the SS LTO particles (149 mAhg−1).

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► Nanosized Li4Ti5O12 was synthesized in supercritical water followed by calcination.
► Li4Ti5O12 shows high initial discharge capacity of 212 mAhg−1.
► Li4Ti5O12 shows good rate performance at high rates of up to 20C (~140 mAhg−1).
► Li4Ti5O12 by supercritical water has better properties than solid state method.