Preparation of Spherical LiFePO4/C Cathode Materials by Spray Drying Method Assisted by PEG

Spherical LiFePO4/C cathode materials were successfully prepared by spray drying method combined with hightemperature sintering method using Fe(NO3)3·9H2O, LiH2PO4 and PEG400 as iron, lithium, phosphorus and carbon sources. The influences of solution concentration, inlet air temperature and feeding rate on the sample morphology and tap density of LiFePO4/C during the spray drying were studied. Upon reducing the solution concentration, the sphericity was deteriorated, and the particle size decreased while the particle size distribution became narrow. Inlet air temperature has great impact on the sphericity and particle size distribution of particles obtained. The optimized temperature is 140 ℃. The particle size reduced upon increasing the feeding rate. However, over high feeding rate deteriorated the sphericity. The obtained LiFePO4/C particles have a tap density of 1.43 g/cm3, a discharge capacity of 120.5 mAh/g under 5C. Their capacity almost don′t decay after 50 cyclings.