锂离子电池LiFePO_4新型合成方法及改性研究

A Novel Synthesis Method of LiFePO_4 and Its Modification Research

采用乙醇体系的溶胶-凝胶法制备了LiFePO_4,通过Mg^(2+)掺杂对其进行了改性,最后以葡萄糖为碳源,制备了不同含碳量的Li_(0.98)Mg_(0.01)FePO_4/C复合材料。采用X射线衍射、扫描电子显微镜表征了材料的微观结构,对材料进行了电化学性能测试。结果表明,在Mg^(2+)掺杂产物中,Li_(0.98)Mg_(0.01)FePO_4在0.1C下首次放电比容量高达140.1mAh·g^(-1);Li_(0.98)Mg_(0.01)FePO_4/C复合材料中,含碳量为6%的材料性能最佳,尤其是高倍率放电性能有显著提高。

In this work,LiFePO4 is prepared applying an ethanol based sol-gel mute. And then the material is modified through Mg-doping. Lio. 9s Mg0. 01 FePO4/C composite materials of different carbon contents are synthesized using glucose as carbon resource. The structural and microstructural characterizations are performed by the study of X- ray diffraction and scanning electron microscopy. The charge-discharge cycling test is used to characterize the electro- chemical performances of the obtained LiFePO4. The results demonstrate that Li0.98Mg0. 01 FePO4 has the highest initial discharge specific capacity among all the materials with different Mg contents doped. It is as high as 140. 1mAh · g-1 with a discharge rate of 0. 1 C. Among the Li0.98 Mg0. 01 FePO4/C composite materials, the sample with6% carbon has the best performances, especially the high-rate discharge performance of which is improved obviously.