Synthesis and Electrochemical Performance of Li0.99Nb0.01Fe1-xMgxPO4/C Cathode

The multiple doping Li-ion battery cathode materials Li0.99Nb0.01Fe1-xMgxPO4/C(x=0, 0.01, 0.02, 0.03, 0.04) were synthesized by two-step solid state reaction. The prepared samples were characterized by X-ray diffractometry, SEM and galvanostatic charge-discharge test. The results show that Li0.99Nb0.01Fe1-xMgxPO4/C samples are pure olive phase, and appropriate amount of doping ions of NV and Me can reduce the particle size. Li0.99Nb0.01Fe0.97Mg0.03PO4/C has the best electrochemical performance. At room temperature, The initial discharge capacity of the sample delivers 153.7, 149.7, 144.6 and 126.4 mAh.g(-1) at 0.2, 1, 2 and 4C rates (1C=170 mA.g(-1)), even at 8C rate, the initial discharge capacity of the sample remains 92.2 mAh.g(-1). In addition, it shows excellent cycle stability at different rates.