高温固相法制备LiFePO4/C正极材料及其性能

Preparation and Properties of Lithium Iron Phosphate Cathode Materials by High Temperature Solid State Method

为了提高磷酸铁锂的能量密度,本文通过两步高温固相反应法合成了锂离子电池正极LiFePO4/C复合材料,利用XRD、SEM、TEM等方法对该正极材料的晶体结构、表面形貌进行了分析研究。实验结果表明,LiFePO4/C具有单一的橄榄石结构,通过掺杂前驱体10%(质量分数)的葡萄糖合成的材料具有良好的充放电性能和循环稳定性能球状,LiFePO4为锂离子的迁移和扩散提供了通道,有利于电化学性能的提升。在0.1C倍率下进行充放电测试,首次放电比容量可达161mAhg^-1,在2C下循环了100次后复合材料的容量为148mAhg^-1,库仑效率高达98%,结果表明碳包覆的LiFePO4样品的电化学性能得到了很大提高。

In this paper, the cathode LiFePO 4 /C composite material of being used in inlithium ion battery was synthesized by two- step high temperature solid state reaction. The crystal structure and morphology of the LiFePO 4 /C were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM). The experimental results show that LiFePO 4 /C has a single olivine structure, The materials synthesized by doping 10%(mass fraction) of glucose precursor have good charge -discharge performance and cyclic stability. The spheroidal LiFePO 4 Provides a channel for the transport and diffusion of lithium ions, which is beneficial to the improvement of electrochemical performance.The charge -discharge test at a rate of 0.1C shows that the initial discharge specific capacity can reach 161 mAhg^-1 ,The capacity of the composite after 100 cycles is 148 mAhg^-1 at 2C,Coulomb efficiency is 98%.The results show that the electrochemical properties of carbon -coated lithium iron phosphate samples has been greatly improved.