分别以5种含碳有机物为碳源,通过固相热裂解法制备了5种LiFePO_4/C复合正极粉体材料,利用XRD和拉曼光谱表征了复合粉体中碳的结构.复合材料含有单一的磷酸铁锂相,裂解碳以无定型形式存在.不同裂解碳D、G拉曼峰的强度有所不同,其比值R反映了石墨化程度的强弱.对于石墨化程度高的LiFePO_4/C复合正极材料,其电子电导性能高,反映在电池容量性质上就是电池容量高.比较不同有机前驱体对复合正极材料的作用效果,聚乙烯醇是较佳的选择.
LiFePO_4/C composite cathode material was prepared by solid-phase pyrolysis process with five kinds of organic carbon as the source. The structure of the carbon in the composite powder was characterized by XRD and Raman spectrum. The single LiFePO_4 phase and amorphous carbon can be found in the products. The intensity of the D, G bands in different organic matter is varied. The Raman intensity ratio of D/G bands reflects the degree of graphitization. The LiFePO_4/C compound cathode material with high degree of graphitization has high electronic conductivity, which also has high battery capacity. Comparing the effect of different organic precursor on the performance of the compound cathode material, PVA is optimum.
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