LiFePO4/C制备工艺的优化及其性能

Optimization of the synthesis technology of LiFePO_4/C and its performance

用共沉淀法制备了球形NH4FePO4.H2O前驱体,再与Li2CO3和葡萄糖混合用固相焙烧法制备了LiFePO4/C正极材料。利用正交实验考察了焙烧温度、焙烧时间、球磨时间、x(Li)∶x(Fe)和葡萄糖用量等对材料首次放电比容量的影响,得到了最佳工艺条件。通过XRD、SEM、FTIR和恒流充放电测试仪等测试了材料的结构和电化学性能。所得材料在室温下电流密度为0.1、0.5和1C时首次放电比容量分别为147.6、136.7和122.3mAh/g,循环50次后容量分别为142.8、127.3和106.7mAh/g;在60℃下电流密度为0.5C时,其首次放电比容量为163.8mAh/g,循环性能良好。

The precursor of NH4FePO4·H2O was synthesized by co-precipitation.The cathode material of LiFePO4/C was synthesized by sintering the NH4FePO4·H2O,Li2CO3 and dextrose.The effects of roasting temperature and time,ball-milling time,the molar ratio of x（Li）∶x（Fe） and the dosage of dextrose on the initial discharge specific capacity were studied through orthogonal tests,thus optimized technology were gained.With the help of XRD,SEM,FTIR and constant current charge-and-discharge instrument,the structure of material and its electrochemical performance were tested.Under the optimized technology,the initial discharge specific capacities were 147.6,136.7 and 122.3mAh/g at 0.1,0.5 and 1C rate respectively,at room temperature.After 50 times of circulation,its discharge specific capacities changed to 142.8,127.3 and 106.7mAh/g respectively.And its initial discharge specific capacity was 163.8mAh/g at 0.5C,at 60℃,and had good cycle performance.