催化化学气相沉积法(CCVD)制备多孔LiFePO_4/C复合材料的研究(英文)

Synthesis of Porous LiFePO_4/C Composite Materials by CCVD Method

以C2H2为碳源,Fe为催化剂,纳米FePO4为原料,采用催化化学气相沉积法(CCVD)合成多孔LiFePO4/C正极材料。经BET、SEM、CHON有机元素分析仪、XRD等手段对复合材料进行结构分析表征。结果表明,该复合材料具有连续贯通的三维导电网络结构,大的比表面积以及多重孔隙的类球形结构,含碳量为4.42%(质量分数),低于传统碳热还原法所制备的材料。电化学测试表明,该材料在0.1、1、5、10 C倍率下,放电比容量分别为147,141,126,110 m Ah·g-1,高倍率充放电性能大大提高,另外,该材料1 C循环80次后,放电比容量基本没有降低,显示了良好的循环稳定性能。

Porous LiFePO4/C composite was in-situ prepared by a catalytic chemical vapor deposition（CCVD） method in a fluidized bed reactor, using ethyne as carbon source, ferrum as catalyst, and nano-FePO4 as reactant. The composite was analyzed and characterized by BET, SEM, CHON organic element analyzer and XRD. Results show that the composite possesses a continuous three-dimensional conductive network, high specific surface area and hierarchical multimodal porous subsphere structure. Its carbon content is 4.42 wt%, which is less than that by the conventional method. The porous LiFePO4/C composite shows the discharge capacities of 147, 141, 126 and 110 m Ah·g^-1 at rates of 0.1, 1.0, 5.0 and 10 C, respectively, gaining better high rate charge-discharge performance. In addition, the discharge capacity of porous LiFePO4/C composite rarely loses at 1 C rate after 80 cycles, which exhibits better cycling performance than that of traditional carbon coated LiFePO4.