| LiFePO4/C composite materials is considered to be one of the most potential cathode materials for lithium-ion, there are many synthesis methods, however, LiFePO4 precursor prepared by microwave drying method is reported rarely. In this paper, LiFePO4 precursor was prepared by microwave drying method, and through high temperature sintering synthesized the LiFePO4/C cathode material, the preparation process was optimized, and researched the scale-up experiment. The samples were analyzed and characterized by TG-DSC, FTIR, XRD, SEM, TEM, CV and constant current charge-discharge experiments, the results showed that:(1) LiFePO4 precursor was prepared by microwave drying method with high efficiency, the preparation time is only about one-fifth of the rotary evaporation method, and the composite material has good electrochemical properties, its initial discharge capacities under 0.1C and 1C rates were 165.7mAh/g and 147.3mAh/g.(2) With the reduction in the amount of added citric acid, the precursor preparation time and volume expansion also reduced, but the discharge capacity of the synthetic material was decreased; The LiFePO4/C composite material synthesized with n(CA):n(Fe)=0.2:1 had the best comprehensive properties:Initial discharge capacities were up to 159.8mAh/g and 142.5mAh/g at 0.1C and 1C; Cycle stability was excellent, only 3.7% capacity fading after 100 discharge-charge circles at 1C.(3) The particle morphology and electrochemical properties of LiFePO4/C composite material synthesized by the scale-up experiment were relatively close with the small test sample, and its initial discharge capacities under 0.1C and 1C rates were 160.6mAh/g and 139.1mAh/g. |
