锂离子电池LiNi_xFe_(1-x)PO_4正极材料的制备及其电化学性能

Synthesis and electrochemical properties on LiNi_xFe_(1-x)PO_4 cathode materials of lithium-ion battery

本文以蔗糖为碳源,采用固相法合成了锂离子电池LiNixFe1-xPO4(x=0、0.05、0.1、0.2和0.3)正极材料,通过XRD和SEM等表征所合成的产物为多孔炭和LiFePO4相以恒电流充放电和电化学阻抗谱研究了材料的电化学性能,结果LiNi0.1Fe0.9PO4的性能最佳,其粒径大小在500～1000nm左右,在2C的充放电条件下,其放电比容量为70.3mAh·g-1,15次循环后容量保持率达90%。

We used sucrose as carbon source to synthesize LiNixFe1-xPO4 （ x=0,0.05,0.1,0.2 and 0.3） cathode material by the solid state method. The samples were characterized by XRD and SEM, the results indicated that LiNixFe1-xPO4/C composite consists of a single LiFePO4 phase and amorphous carbon. The electrochemical performance was investigated by the charge-discharge curves, cycle life and electrochemical impedance spectroscopy. It was found that the electrochemical properties of LiNi0.1Fe0.9PO4 is the best among all the synthesized material. The particle size was about 500-1000 nm, an initial discharge capacity of 70.3 mAh·g^-1 was achieved at room temperature with discharge rate of 2 C, and the capacity retaining was 90 % after 15 cycles.