Enhanced high rate capability of dual-phase Li4Ti5O12-TiO2 induced by pseudocapacitive effect

The dual-phase Li4Ti5O12-TiO2 nanocomposite is successfully synthesized by a hydrothermal route with adding thiourea. The electrochemical performance of the dual-phase nanocomposite as anode for lithium-ion batteries is investigated by the galvanostatic method, cyclic voltammetry and electrochemical impedance spectra. It is demonstrated that the dual-phase Li4Ti5O12-TiO2 nanocomposite presents the improved electrochemical performance over individual single phase Li4Ti5O12 and anatase TiO2 samples. After 300 cycles at 1 C, the dual-phase Li4Ti5O12-TiO2 nanocomposite can still maintain the large discharge capacity of 116 mAh g(-1). It indicates that the as-prepared nanocomposite can endure great changes of various discharge current densities to retain a good stability. The large discharge capacity of 132 mAh g(-1) is also obtained at the large current density of 1600 mA g(-1) upon cycling. In particular, as verified by the cyclic voltammetry, the pseudocapacitive effect is induced due to the presence of abundant phase interfaces in the dual-phase Li4Ti5O12-TiO2 nanocomposite, which is beneficial to the enhanced high rate capability and good cycle stability. (C) 2011 Elsevier Ltd. All rights reserved.