基于纳米CT对磷酸铁锂三维形貌结构的研究

3D morphology and structure of LiFePO_4 based on nanoscale CT

磷酸铁锂具有理论电容量高,原料成本低,且对环境友好的优点,因而成为锂离子电池正极材料的研究热点。作为电极材料,压实的磷酸铁锂电极片的内部结构会显著影响其充放电性能。纳米尺度X射线计算机断层扫描技术(纳米CT)具有空间分辨率高,可无损探测材料内部的三维形貌结构。本文使用纳米CT对一种商业化磷酸铁锂电极片材料的内部形貌结构进行三维扫描;使用Avizo软件对扫描后的数据进行处理计算,从而对该材料的孔隙结构进行定性和定量分析。研究结果表明:该磷酸铁锂电极片材料的孔隙分布分散,孔隙体积分布跨度较大,孔隙率为29.16%。

LiFePO4 is a hot research topic as cathode material in Li-ion battery due to its high theoretic capacity, low cost of raw material and environmental friendliness. As an electrode material, the charge/discharge capacity of compacted LiFePO4 is remarkably affected by its inner structure. Nanoscale X-ray computed tomography （ Nano CT） is suitable for nondestructive characterization of materials 3d innermorphology and structure with high spatial resolution. In this paper, a commercialized LiFePO4 electron slice was characterized by Nano CT to obtain its inner 3d morphology and structure. The pore structure of LiFePO4 slice was qualitatively displayed and quantitatively computed by using software Avizo based on the scanned data by Nano CT. The results show that pores in LiFePO4 electron slice are dispersedly distributed and pore volume distributes in a very large range. The porosity is 29？16%.