Abstract: In order to improve the performance of LiFePO₄, Li_1-xTi_xFePO₄(x=0.00, 0.01, 0.02, 0.03, 0.05 and 0.07,mol fraction) with Ti(Ⅳ) dopant was prepared. Crystal structure and charge/discharge
performance of Ti(Ⅳ) doped LiFePO₄ were investigated by X-ray diffraction using the Rietveld method and electrochemical measurement, respectively. Single phase Li_1-xTi_xFePO₄
can be prepared by solid state reaction. Li_0.98Ti _0.02FePO₄ shows higher capacity than LiFePO₄ through the research on Li_1-xM_xFePO₄. As Li_0.98Ti_0.02PO₄ is
charged and discharged at 80mA/g, its 2nd and 20th discharge capacity is 136.606 and 128.388mAh/g, respectively. The results show that low concentration Ti(Ⅳ) dopant can increase
the capacity and cycle performances of LiFePO4. because it not only causes the change of atomic position and distance and the shrinkage of crystal cell, but also increases the concentration of coexisted
Fe^3+/Fe²⁺ in LiFePO4, which increases the electrical conductivity of LiFePO₄.

Key words: lithium ion battery, cathode material, LiFePO₄