论文部分内容阅读
采用高温固相法合成锂离子正极材料LiFePO4/C,在合成过程中分别采用高能球磨和引入表面活性剂。用扫描电镜(SEM),粒度分布仪和X-ray粉末衍射仪(XRD)对材料微观形貌、晶体结构进行表征,并进行电化学性能测试。结果表明:所制备LiFePO4/C材料晶型完美,二次颗粒分布范围1~30μm,一次颗粒分布范围100~200nm,具有较高的振实密度1.3g/cm3和良好的电化学性能。在25℃时,0.1C和5C倍率下放电容分别达到161.5和120mAh/g。在-20℃,0.1C下放电容仍然能达到123.5mAh/g。在25℃,高倍率5C下,LiFePO4/C显示优异的循环性能,经过300次循环后容量保持率还能达到97%。研究结果表明所制备LiFePO4/C正极材料能够满足混合动力汽车应用。
High-temperature solid-state synthesis of Li-ion cathode material LiFePO4 / C, respectively, in the synthesis process using high-energy ball mill and the introduction of surfactants. The microstructure and crystal structure of the material were characterized by scanning electron microscopy (SEM), particle size distribution analyzer and X-ray powder diffraction (XRD). The electrochemical properties of the material were characterized. The results show that the prepared LiFePO4 / C materials have perfect crystal form, the distribution range of secondary particles is 1 ~ 30μm, the primary particles are distributed in the range of 100 ~ 200nm, and have high tap density of 1.3g / cm3 and good electrochemical performance. At 25 ℃, 0.1C and 5C rate of discharge capacity reached 161.5 and 120mAh / g respectively. At -20 ℃, 0.1C discharge capacity can still reach 123.5mAh / g. LiFePO4 / C shows excellent cycling performance at 25 ° C and 5C of high magnification with a capacity retention of 97% after 300 cycles. The results show that the prepared LiFePO4 / C cathode material can meet the hybrid vehicle applications.