用水热法制备FeF3(H2O)4.5前驱体,在惰性气体保护下将前驱体制备成含微量水的FeF3(H2O)0.33,FeF3(H2O)0.33与乙炔黑球磨制备成锂二次电池新型纳米级的复合正极材料。通过傅里叶红外光谱(FT-IR)、X射线衍射(XRD)、扫描电镜(SEM)和电化学测试等研究了材料的结构和电化学性能。结果表明,所制备的FeF3是含微量水的FeF3(H2O)0.33,具有典型正交晶系结构,并且所制备的材料粒径均匀。FeF3(H2O)0.33/C复合材料在充放电倍率为0.1C和电压范围在2.0~4.5V内,具有较高的放电比容量和容量保持率。其首次放电比容量为190mAh/g,在循环30次后容量保持率为第2次的86%。
The precursor of FeF3(H2O)4.5 was synthesized by hydrothermal method. Then the precursor was prepared in the inert gases to get the minim-water FeF3(H2O)4.5. The novel cathode material carbon-metal fluoride composites of lithium rechargeahle batteries were prepared through mechanical milling with acetylene black. The structural and electrochemical properties of the as-prepared samples were investigated by fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM) and electrochemical experiments. The results showed that the prepared FeF3 was actually the minim-water FeF3(H2O)4.5 with typical orthorhombic structure, and the particle sizes of the samples were distributed uniformly. It's found that FeF3(H2O)4.5 composite showed an improved discharge capacity retention and a very high discharge specific capacity at 0.1C rate in the voltage range of 2. 0-4. 5V. The FeF3(H2O)4.5 composite electrode delivered an initial discharge capacity of 190mAh/g during the first cycle and the capacity retention at the 30th cycle was 86% relative to the second cycle.