Sonochemical synthesis of the high energy density cathode material VOPO4·2H2O

We report on a high energy density VOPO4·2H2O cathode material prepared by the sonochemical method. VOPO4·2H2O is rapidly prepared within 15 min by ultrasonic irradiation of an aqueous solution containing V2O5 and H3PO4. The sonochemically synthesized VOPO4·2H2O forms rectangular polycrystals 1¯3 mu m in size as observed by transmission electron microscopy (TEM) and selected area electron diffraction. X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopic studies confirmed the phase purity. The electrochemical test of the onochemically synthesized VOPO4·2H2O in a nonaqueous Li salt electrolyte showed a cell voltage of 3.6 V and an energy density of 486 Wh/kg, along with a good reversibility for lithium insertion/extraction.