有机模板剂辅助喷雾干燥法制备LiFePO4/C正极材料及其电化学性能研究  

Preparation and Electrochemical Performance of LiFePO_4/C by Spray Drying Method Assisted with Organic Template

作　　者：刘全兵[1] 蒋阳梅[1] 宋慧宇[1] 廖世军[1] 

机构地区：[1]华南理工大学广东省燃料电池技术重点实验室,化学与化工学院,广东广州510641

出　　处：《电化学》2012年第1期18-23,共6页Journal of Electrochemistry

基　　金：国家自然科学基金(No.20876062,No.21076089)资助

摘　　要：分别使用3种有机物辅助模板剂,由喷雾干燥制得LiFePO4/C复合正极材料,X射线衍射(XRD)、扫描电镜(SEM)表征、考察了不同模板剂对样品的形貌和性能的影响.交流阻抗(EIS)、循环伏安(CV)和恒电流充放电测试电极性能.结果表明:样品的形貌和结构因添加不同的有机模板剂而改变.无模板剂时,得到的样品是光滑实心球;以聚乙烯醇(PVA)、柠檬酸和葡萄糖等作有机模板剂,可制得纳米颗粒团聚成的均匀微米球形、多孔球形和鸟巢状样品.其中以PVA为辅助模板剂制得的LiFePO4/C电极,其电荷转移电阻和比容量都较优异.该样品在0.1C和5C倍率下放电比容量分别达156.7和92.1 mAh.g-1,并呈现出大的倍率充放电平台及优良的倍率循环性能.In this work, the LiFePO4/C composites were prepared by the spray drying and carbothermal method, and were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, cyclic voltammetry （CV）, electrochemical impedance spectroscopy （EIS）, and galvanostatic charge-discharge measurements. The effects of the organic assisted templates on the morphologies and electrochemical properties of the LiFePO4/ C composites were investigated. The results showed that the morphology and microstructure of the composites could be tuned by incorporating With the different templates. The morphology of the .composite appeared to be solid microspheres if no organic template was added, while porous microspheres, nest-like aggregation, and uniform nano-micro spheres,if citric acid,glucose and polyvinyl alcohol（PVA） were used as the templates,respectively. Among all the samples, the composite prepared with PVA as a template also exhibited the best properties in batteries, including the highest tap density, the lowest charge transfer resistances and the highest capacities. The best discharge capacities were measured to be 156.7 and 92.1 mAh · g-1 at 0.1 and 5.0C rate,respectively. The ob- vious charge-discharge plateaus at high rates and excellent cycling performance at various rates were achieved.

关 键 词：正极材料 喷雾干燥 辅助模板 聚乙烯醇 

分 类 号：TM912[电气工程—电力电子与电力传动]