采用高速球磨与高温固相反应相结合的方法合成了LiMnyFe1-yPO4(0.1≤ y≤1.0)锂离子电池正极材料, 并对其晶体结构、表观形貌和电化学性能进行了研究. 结果表明, 所合成的LiMnyFe1-yPO4为单一橄榄石型结构, 粒径分布较均匀. 当以小电流密度(0.1C)充放电时, LiMn0.1Fe0.9PO4具有最高的放电比容量, 为145mAh/g; LiMn0.6Fe0.4PO4质量比能量最高, 达568Wh/kg. LiMnyFe1-yPO4的倍率放电性能随着y的增加而降低, 这主要是材料在4.0V平台的容量损失造成的; LiMn0.1Fe0.9PO4具有最佳的倍率性能: 以0.5、1.5C倍率进行放电, 放电容量分别达到130、109mAh/g.
The LiMnyFe1-yPO4 (0.1≤ y≤1) cathode materials for lithium-ion batteries were synthesized by solid-state reaction combined with high-rate ball milling. The crystalline structure, morphology of particles, and electrochemical performance of the sample were investigated by X-ray diffraction, scanning electron microscope, charge-discharge test and cyclic voltammetry. The results show that all LiMnyFe1-yPO4 samples are simple pure olive-type phase with small particles, and uniformly distribution of gain sizes. At low rate of 0.1C, the first specific discharge capacity of LiMn0.1Fe0.9PO4 is the highest with 145mAh/g and LiMn0.6Fe0.4PO4 shows the highest energy density of 568Wh/kg. The rate capabilities of the samples are strongly influenced by y value of LiMnyFe1-yPO4. LiMn0.1Fe0.9PO4 shows the best rate capabilities with discharge capacity of 130mAh/g at 0.5C rate and 109mAh/g at 1.5C rate.
1 Padlhi A K, Nanjundaswamy K S, Goodenough J B. J. Electrochem. Soc., 1997, 144 (4): 1188-1194.
2 Andersson Anna S, Thomas John O, Kalska Beata, et al. Electrochemical and Solid-state Letters, 2000, 3 (2): 66-68.
3 Padhi A K, Nanjundaswamy K S, Masquelier C, et al. J. Electrochem. Soc., 1997, 144 (5): 1609-1613.
4 Chen J, Zhang Y S. Int. J. Hydrogen Energy, 1995, 20: 235-240.
5 Atsuo Yamada, Sai-Cheong Chung. J. Electrochem. Soc., 2001, 148 (8): A960-A967.
