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采用改进型原位限制聚合法制备具有核-壳结构的纳米LiFePO_4/C颗粒.。并通过XRD,HRTEM,电化学工作站等测试手段研究了所制备粉体的相组成,微观结构和电化学性能。XRD结果表明所制备的LiFePO4/C具有晶型完整的橄榄行结构,壳层炭为作晶。HRTEM照片显示所制备的LiFePO4/C粒径在18.2~54.5 nm之间,炭层均匀包覆在LiFePO4颗粒外表面,厚度在2~10nm之间。700℃合成的LiFePO_4/C核-壳材料的首次放电容量为142 mAh/g,经过40次充放电循环后,容量保持在132 mAh/g,容量保持率在93.0%。其充放电容量受电子导电、锂离子扩散速率的共同影响。
Preparation of nano-LiFePO 4 / C particles with core-shell structure by modified in situ polymerization. The phase composition, microstructure and electrochemical properties of the prepared powders were investigated by means of XRD, HRTEM and electrochemical workstation. XRD results show that the prepared LiFePO4 / C has a crystal structure of olive rows, shell carbon as a crystal. HRTEM photos show that the prepared LiFePO4 / C particle size is between 18.2 and 54.5 nm, the carbon layer is uniformly coated on the outer surface of the LiFePO4 particle and the thickness is between 2 and 10 nm. The initial discharge capacity of LiFePO 4 / C core-shell material synthesized at 700 ℃ was 142 mAh / g. After 40 charge-discharge cycles, the capacity was maintained at 132 mAh / g and the capacity retention was 93.0%. Its charge and discharge capacity by the electronic conductivity, lithium ion diffusion rate of the common impact.