Solvothermal synthesis and electrochemical characterization of amorphous lithium titanate materials

Lithium titanate materials used for anode in Li-ion batteries were solvothermally synthesized from tetrabutyl titanate and LiOH at 140 degrees C. The synthesized powders show mainly amorphous state with a little amount of crystalline phase. The synthesized powders are a mixture composed of lithium titanium oxide and a complex compound (CH3(CH2)(3)O)(4-x)Ti(OLi)(x). Sample with Li/Ti = 1.0 shows larger particle size and relatively good crystallinity compared to sample with Li/Ti = 0.8. Both of them display excellent cycleability with reversible capacity of ca. 85 mA/g at current density of 175 mA/g. When charged and discharged at 525 mA/g, the former keeps a good cycling stability, however, the later exhibits rapid capacity degradation. The relatively good crystallinity is certainly favorable to the structure stability and thus the cycling stability of electrode. Despite the low specific capacity of the synthesized lithium titanate material, the excellent cycling stability at high current density will make it a promising candidate for electrode material used in high power Li-ion batteries or capacitors. (C) 2007 Elsevier B.V. All rights reserved.