摘要
以草酸亚铁为铁源,磷酸二氢锂为锂源,以葡萄糖为第一相碳源,乙炔黑为第二相碳源,两步高温固相法合成碳包覆磷酸铁锂(LiFePO4/C)正极材料,采用X射线衍射(XRD)、扫描电子显微镜(SEM)和显微激光拉曼光谱等分析方法对合成样品的物相、表面形貌及碳结构进行表征,并对样品的恒流充放电性能进行了测试,探讨了乙炔黑的加入对材料电化学性能的影响。结果表明采用二相碳合成的LiFePO4/C材料为纯相磷酸铁锂;碳包覆LiFePO4材料中有石墨结构的有序碳生成,且电子电导率达到6.89×10-5S/cm;具有良好的电化学性能,在0.5 C下放电比容量达到161mAh/g,5 C下放电比容量为122.7 m Ah/g,3 C下循环30次后容量保持率为95.97%。
Carbon-coated LiFePO4/C composite material was synthesized via two step high-temperature solid-state reaction method using FeC204 as Fe source, LiH2PO4as Li source and using glucose for the first phase of carbon and acetylene black for the second phase. The phase composition, surface morphology and carbon structure of the LiFePO4/C were studied by the methods of XRD, SEM and Raman. The constant current charge and discharge performance of the sample was tested, and the effects of acetylene black on the electrochemical performance of samples were investigated. The results show that LiFePO4/C synthesized with two phases of carbon sources are all single-phase materials and carbon-coated LiFePO4 generates ordered carbon with graphite structure, improving the conductivity of LiFePO4/C to 6.89 ×10^-5S/cm, having good electrochemical performance. The discharge specific capacities are 161 and 122.7 mAh/g at 0.5 C and 5 C, respectively. The capacity retention is 95.97% after 30 cycles at3C.
出处
《电源技术》
CAS
CSCD
北大核心
2015年第6期1162-1164,共3页
Chinese Journal of Power Sources
基金
国家自然科学基金(51064004
51364004
21063003)
广西自然科学基金(2011GXNSFA018016)
关键词
锂离子电池
正极材料
磷酸铁锂
固相反应
乙炔黑
lithium ion batteries
cathode materials
LiFePO4
solid-phase reaction
acetylene black
