磷酸铁锂正极材料水热法制备及性能研究
刘晓斐1，黄佳琦2，朱万诚1,*，刘芯言2，彭翃杰2，张强2,* ，魏飞2
1曲阜师范大学化学工程系，山东省曲阜市静轩西路57号，273165
2清华大学化学工程系，北京市海淀区清华园1号，100084
*Email: zhuwancheng@https://www.doczj.com/doc/1a4460832.html, 1, zhangqiangflotu@https://www.doczj.com/doc/1a4460832.html, 2
摘要：橄榄石型LiFePO 4具有理论比容量高，热稳定性好等系列优点，是新一代动力型锂离子电池理想的正极材料之一，但本身结构缺陷、电子电导率低、锂离子扩散速率慢等限制了其实际应用。本文以H 3PO 4, FeSO 4·7H 2O 和LiOH·H 2O 为原料，考察了非纯水溶剂氮甲基吡咯烷酮（NMP ）对LiFePO 4水热合成的影响，并采用蔗糖为碳源对其进行碳包覆改性，探究了相关电化学性能。结果表明，NMP 能有效抑制晶粒过度生长改善分散性，碳包覆则能够促进LiFePO 4颗粒进一步细化；碳包覆LiFePO 4正极材料在0.2 C 和5 C (1 C=170 mA/g)
Fig.1 XRD pattern (a), SEM image (b), and electrochemical performance (c) of the LiFePO 4 cathode materials. 关键词：磷酸铁锂 正极材料 锂离子电池 水热 碳包覆
参考文献
[1] J.J. Wang; X.L. Sun. Energy Environ. Sci. 2011, DOI: 10.1039/c1ee01263k.
[2] O. Toprakci; L.W. Ji; Z. Lin; et al. J. Power Sources. 2011, 196:7692.
Hydrothermal synthesis and properties of LiFePO 4 cathode materials Xiaofei Liu 1, Jiaqi Huang 2, Wancheng Zhu 1,*, Xinyan Liu 2, Hongjie Peng 2, Qiang Zhang 2,*, Fei
Wei 2
1Department of Chemical Engineering, Qufu Normal University, 57#, W Jingxuan Rd, Qufu,
Shandong, 273165
2Department of Chemical Engineering, Tsinghua University, 1#, Tsinghua Rd, Beijing, 100084 Abstract: Olivine-type LiFePO 4 has been one of the most promising cathode materials for lithium ion batteries due to its series of advantages such as high theoretical capacity, and excellent thermal stability. However, the inherent structural defect, low electronic conductivity and Li + diffusion rate limit its practical applications. In this work, pure phase LiFePO 4 was successfully synthesized by a facile hydrothermal route, using H 3PO 4, FeSO 4·7H 2O and LiOH·H 2O as the raw materials. The effects of solvent and carbon coating on the as-synthesized product were investigated. The results showed that, N-methyl-2-pyrrolidone (NMP) was beneficial to inhibit the over growth of the nanocrystals and thus improve the dispersion, meanwhile, carbon coating was helpful to obtain ultra-fine particles. Moreover, the charge-discharge test indicated that the discharge specific capacities of the optimized samples under 0.2 C and 5.0 C (1 C=170 mA/g) at room temperature were of 130 mAh/g and 90 mAh/g, respectively.
Key words: LiFePO 4, cathode material, lithium ion battery, hydrothermal, carbon coating -5000
500
1000
1500
20002500300035004000LiFePO 4JCPDS NO.83-2092300 nm (b)