摘要
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LiFePO_4/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,LiFePO_4/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0.1 C倍率下进行充放电测试,首次放电比容量可达161 m Ahg-1,在2 C下循环了100次后复合材料的容量为148 m Ahg~(-1),库仑效率高达98%,结果表明碳包覆的LiFePO_4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 of0.1 C shows that the initial discharge specific capacity can reach 161 m Ahg~(-1),The capacity of the composite after100 cycles is 148 m Ahg~(-1) at 2 C,Coulomb efficiency is 98%.The results show that the electrochemical properties of carbon-coated lithium iron phosphate samples has been greatly improved.
引文
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