A novel sol-gel method based on FePO4·2H2O to synthesize submicrometer structured LiFePO4/C cathode material

▶ LiFePO4/C cathode material was synthesized with a novel sol-gel method-cheap FePO4·2H2O was chosen as both iron and phosphorus sources which could reduce the synthesis cost; cheap H2C2O4 was chosen as both reductant and complexant which was able to form transparent and homogeneous sols; in the calcination process, the produced CO and CO2 gases could prevent the particles from aggregating and growing up which was helpful to synthesize small and well-distributed particles. The initial discharge capacities of the obtained LiFePO4/C material were as high as 160, 150, 134, 128, 118 and 106 mAh g−1 at 0.1, 1, 2, 3, 5 and 10 C rates, respectively, in the potential range of 2.5-4.2 V. The cyclic performances were good, with a discharge capacity retention of 98.7% after 50 cycles at 0.1 C rate. The improvement of the electrochemical performances could be attributed to fast electronic conductivity and lithium-ion diffusivity resulting from the carbon-coated submicrometer-size particles.