THE STUDY ON SYNTHESIS AND MODIFICATION FOR IRON PHOSPHATE

In order to improve the electrochemical performance of FePO4, the method of Cr3+ ion-doped FePO4 was proposed in this paper. FePO4 and doped Fe1-xCrxPO4 (x = 0.02, 0.04, 0.06 and 0.08) were prepared by homogeneous co-precipitation followed by spray drying method, and then the samples were sintered at different temperatures (380 degrees C, 460 degrees C, 550 degrees C and 650 degrees C). Physical-chemical properties were characterized by using thermogravimetric analysis (TG), X-ray diffraction (XRD) and scanning electron microscope (SEM); electrochemical behavior of the samples were analyzed using charge-discharge test, electrochemical impedance spectroscopy (EIS). The results indicated that the Cr3+ doping can effectively improve the electrochemical performance of FePO4. Fe0.96Cr0.04PO4 sintered at 460 degrees C showed the highest specific capacity of 109.7 mAh/g for the 1st cycle at 0.05 C. In addition, the doping mechanism for FePO4 was discussed in this paper.