中文摘要：

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结构，孔径在介孔范围内分布集中，比表面积分别为73.7、69．9m^2·g^-1：碳纳米管以嵌入或包埋的形式在多孔LiMnPO4中形成了高导电性的三维网络．恒流充放电测试表明，与纯LiMnPO4相比，复合材料具有更高的放电比容量，在0．05C、2C倍率下的放电容量分别为108．8、33．2mAh·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．

英文摘要：

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.