通过固相法合成了裂解碳包覆的具有亚微米球形颗粒团簇微结构的LiFePO4粉体材料.材料中裂解碳百分含量为5.01%,一次颗粒粒径在200-600nm,团簇体粒径在10μm左右. 在0.1、0.2、0.5和1C的充放电速率下,研究了材料的比容量和循环稳定性的变化.当充放电速率<1C时,随着充放电速率的增大,材料的充放电平台和比容量并不随速率的增大而发生较大变化,当充放电速率≥1C时,材料的充放电电压平台迅速升高(充电)或降低(放电),比容量也有较大的降低;随着充放电次数的增加,材料的比容量有所增加,然后趋于稳定.在30 个循环后材料的放电比容量分别为:131.7、129.1、123.5和114.4mAh/g.
Carbon covered LiFePO4 powders with the microstructure of submicro-particles aggregated 5.01wt% carbon content,
and the diameter of aggregated particle of 10μm were synthesized by solid state sintering processing. The capacity and cycle performance were studied
at the charge and discharge rate of C/10, C/5, C/2 and 1C. The results show that below the rate of C/2, the voltage platform and capacity is not sensitive to the rate.
When the rate is increased to 1C, the capacity is decreased and the voltage platform is increased in charge processing and decreased in discharge
processing. Along with the increasing of cycle number, the capacity is increased to its saturate value. After 30 cycles, the capacities are
131.7, 129.1, 123.5 and 114.4 mAh/g, respectively.
参考文献
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