Effects of reactant dispersion on the structure and electrochemical performance of Li1.2V3O8

The pure-phase Li1.2V3O8 was synthesized by ultrasonically dispersing Li2CO3 and NH4VO3 reactants. Its structure and morphology compared with the pristine Li1+xV3O8 obtained from the solid-state reaction were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that the compound synthesized at 570 degrees C from the precursor obtained by ultrasonic treatment in anhydrous ethanol has low crystallinity and homogeneous morphology with bar-like shape. Charge-discharge cycling, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) experiments indicate that this sample has relatively high initial discharge capacity and good cycle ability, and it is beneficial to the reversible insertion/extraction of Li+ ions because of the low kinetic resistance. Its discharge capacity reaches 270 mAh g(-1) in the 2nd cycle at 0.2C discharge rate and still retains 210 mAh g(-1) in the 100th cycle in the range of 2.0-4.0 V. (C) 2008 Elsevier B.V. All rights reserved.