摘要
以柠檬酸为络合剂, 采用溶胶-凝胶法制备了多孔LiMnPO4和LiMnPO4/MWCNT(多壁碳纳米管)复合材料. 用X射线衍射(XRD)、场发射扫描电镜(FE-SEM)、N2吸脱附等温曲线(BET)和透射电镜(TEM)对其晶体结构与微观形貌进行了表征. 结果表明, 得到的样品具有橄榄石晶体结构, 物相较纯; 两种材料均具有丰富的多级孔道LiM结n构PO, 孔4中径形在成介了孔高范导围电内性分的布三集维中网, 比络表. 恒面流积充分放别电为测73试.7表、6明9.,9 与 m纯2·gL-iM1; n碳P纳O4米相管比以, 复嵌合入材或料包具埋有的更形高式的在放多孔电比容量, 在0.05C、2C倍率下的放电容量分别为108.8、33.2 mAh·g-1. 电化学交流阻抗谱(EIS)表明MWCNT可以有效提高LiMnPO4的电子导电性. LiMnPO4/MWCNT复合材料具有较优的电化学性能可归因于增强的电子导电性, 连接的孔道结构和高的比表面积.
Porous LiMnPO4 and LiMnPOJMWCNT （multi-walled carbon nanotube） composites were prepared using a citric acid assisted sol-gel method. X-ray diffraction （XRD）, field emission scanning electron microscopy （FE-SEM）, nitrogen adsorption-desorption isotherms （BET）, and transmission electron microscopy （TEM） were performed to characterize their morphologies and structures. The results indicated that fine-sized, well-crystallized olivine LiMnPO4 was synthesized. The interlaced carbon nanotube networks were intimately embedded and incorporated into the porous LiMnPO4 particle to form highlyconductive three-dimensional （3D） networks. The LiMnPO4 particle and LiMnPO,/MWCNT composite had rich hierarchical pores. A detailed analysis showed that the average pore size was in the mesoporous range and specific surface areas of 73.7 and 69.9 m^2·g^-1 were obtained, respectively. Compared with the LiMnPO, particle the LiMnPOJMWCNT composite exhibited much higher specific capacity. When discharged at a rate of 0.05C and 2C the capacities were 108.8 and 33.2 mAh ·g^-1, respectively. The MWCNT effectively improved the electronic conductivity of the hybrid materials as shown by electrochemical impedance spectroscopy （EIS）. The improved electrochemical performance of the LiMnPO4/MWCNT electrode is attributed to the enhanced electrical conductivity caused by the tighter binding of the carbon nanotubes with the LiMnPO4 primary particles as well as by the interconnected open pores with a high surface area.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2011年第9期2123-2128,共6页
Acta Physico-Chimica Sinica
基金
国家重点基础研究发展计划项目(973) (2007CB209703)
国家自然科学基金(20873064)
江苏省普通高校科研创新计划(CXZZ11_0204)
南京航空航天大学博士学位论文创新与创优基金(BCXJ11-10)资助~~
