水热法制备磷酸铁锂的研究.doc

水热法制备磷酸铁锂的研究 摘要 以H3PO4、FeSO4·7H2O、LiOH·H2O 为原料CTAB 和葡萄糖为分散剂和 还原剂 液相反应制备LiFePO4/C 复合材料。其中加入少量的CTAB 和葡萄糖有 利于LiFePO4 晶体的完整生长。X 射线衍射结果显示: 合成的LiFePO4/C 物相单 一、纯正 而未添加葡萄糖直接合成的LiFePO4 存在着杂相 扫描电镜表征表明: 合成的磷酸亚铁锂结晶度较高、粒度分布较均匀、晶粒完整。溶液的PH 值对磷 酸铁锂合成有重要影响在PH 值6-9 范围内得到比较纯净的磷酸铁锂而在 强酸性条件下得到立方相FePO4。充放电性能测试显示: LiFePO4 在0.1C 电流密 度下充放电 其初始放电比容量仅有83 mAh/g而包覆10 质量百分数的导电 碳的LiFePO4/C 复合材料其比容量高达128mAh/g 即使在0.5 C 高倍率充放电 仍保持108 mAh/g。结果表明LiFePO4/C 复合材料具有更优异的电化学性能。 关键词磷酸铁锂正极材料锂离子电池电动链水热法 水热法制备磷酸铁锂的研究 Hydrothermal Synthesis of lithium iron phosphate ABSTRACT With H3PO4 FeSO4 ?? 7H2O LiOH ?? H2O as raw material LiFePO4/C composite is synthesized vie hydrothermal method. A small amount of CTAB and glucose are added as well which is helpful to the crystal growth of LiFePO4. X-ray diffraction results show that LiFePO4/C prepared is single oviline phase with addition of glucose otherwise impurity are detected. Scanning electron microscopy characterization shows that: the synthesis of lithium iron phosphate crystallized well and the particle size distribution is uniform. PH value of the solution affects the reaction products of the synthesis. Charge-discharge performance test shows that at 0.1C rat its initial discharge capacity is only 83 mAh/g while the conductive carbon coating is 10 mass percentage the discharge capacity is up to 128 mAh/g even in the 0.5 C rate it still stays at 108 mAh/g. All the results above show that the LiFePO4 / C composite material synthesized by hydrothermal method has superior electrochemical performance. Key words:Lithium iron phosphate Cathode materialsHydrothermal synthesis lithium-ion batlery Electrie vehicle 水热法制备磷酸铁锂的研究 目录 1 绪论....................................................................................................................................1 1.1 引言.........................................................................................................................1 1.2 磷酸铁锂的基本性质....................................................................