摘要
采用固相反应法在真空气氛下合成了橄榄石型的LiFePO4正极材料。并用X射线衍射、扫描电子显微镜、恒流充放电以及交流阻抗法对其晶体结构、表观形貌及电化学性能进行了研究。与氮气气氛下合成的LiFePO4相比,真空气氛下合成LiFePO4晶体结构并未发生变化,且粒径较小,分布均匀,具有更低的电荷转移电阻和更高的放电比容量。以0.1 C倍率充放电,首次放电比容量可达131.1 mAh/g,即使以1.0 C倍率充放电,首次放电比容量也达107.9 mAh/g;而氮气保护下合成的LiFePO4在0.1 C倍率下首次放电比容量仅118.3 mAh/g,1.0 C倍率下也只有83.0 mAh/g。
Lithium iron phosphate, LiFePO4, as positive electrode material for lithium ion batteries was prepared by high temperature solid - state reaction under vacuum condition. The crystalline structure, particle morphology, and electrochemical performance of the resulting samples were investigated by X - ray diffraction, scanning electron mi- croscopy, charge - discharge tests and a. c. impedance techniques. The results show that under vacuum condition the LiFePO4 has a pure olive -type phase structure with small and uniform particle size, the material exhibits lower in- ternal resistance and higher charge - discharge specific capacity than that prepared under nitrogen atmosphere. The first discharge specific capacity of vacuum prepared LiFePO4 can reach 131. 1 mA1Cg at C/10 rate and 107.9 mAh/g at 1.0 C rate, while for the nitrogen atmosphere prepared material, it is only 118.3 mAh/g at C/10 rate and 107.9 mAh/g at 1.0C rate.
出处
《南昌大学学报（理科版）》
CAS
北大核心
2008年第3期239-242,255,共5页
Journal of Nanchang University(Natural Science)
基金
江西教育厅科研基金资助项目(200715)
关键词
LIFEPO4
真空煅烧
正极材料
锂离子电池
LiFePO4
vacuum calcinations
positive electrode material
lithium ion batteries
