凝胶燃烧法合成5V级正极材料LiNi_(0.5)Mn_(1.5)O_4及其高倍率放电性能  

High Rate Capability of 5V LiNi_(0.5)Mn_(1.5)O_4 Cathode Materials Synthesized via a Gel-Combustion Method

作　　者：代克化[1] 毛景[1] 翟玉春[1] 

机构地区：[1]东北大学材料与冶金学院,沈阳110004

出　　处：《物理化学学报》2010年第8期2130-2134,共5页Acta Physico-Chimica Sinica

基　　金：高等学校博士学科点专项科研基金(20090042120013);沈阳市人才资源开发专项资金(2009010103040)资助项目~~

摘　　要：采用聚乙烯吡咯烷酮(PVP)作为络合剂和燃料以凝胶燃烧法制备了具有优异高倍率放电性能的亚微米LiNi0.5Mn1.5O4材料.用热重/差热分析(TG/DTA)研究了凝胶的燃烧过程,用X射线衍射(XRD)、扫描电镜(SEM)和循环伏安(CV)研究了LiNi0.5Mn1.5O4材料的结构和形貌.结果表明材料为结晶良好的纯尖晶石相结构,由5μm左右的二次颗粒组成,颗粒大小分布均匀,一次晶粒发育良好,粒径在500nm左右.充放电测试表明材料的倍率性能和循环性能十分优异.在3.5至4.9V进行充放电测试,0.5C、1C、4C、8C和10C倍率下放电容量分别为131.9、127.6、123.4、118.4和113.7mAh·g-1.在10C大倍率放电条件下循环100、500和1000次的容量保持率分别为91.4%、80.9%和73.5%.Sub-micron LiNi0.5Mn1.5O4 with excellent high rate performance was synthesized by a polyvinylpyrrolidone-assisted gel-combustion method. Thermogravimetric and differential thermal analyses （TG/DTA） were used to determine the nature of the combustion process of the gel. The structure and morphology of the as-prepared materials were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and cyclic voltammetry （CV）. The results showed that the LiNi0.5Mn1.5O4 powders were single-phase spinel and consisted of uniform secondary particles （5 μm）, which were formed by small primary particles （500 nm）. Galvanostatic charge-discharge tests indicated that the LiNi0.5Mn1.5O4 had an excellent rate capability and cyclic performance. When discharged at a rate of 0.5C, 1C, 4C, 8C, and 10C between 3.5 and 4.9 V, the discharge capacity is 131.9, 127.6, 123.4, 118.4, and 113.7 mAh·g-1, respectively. Upon long cycling under a high discharge rate of 10C, the capacity retentions after 100, 500, and 1000 cycles were 91.4%, 80.9%, and 73.5%, respectively.

关 键 词：锂离子电池 正极材料 LINI0.5MN1.5O4 凝胶燃烧法 聚乙烯吡咯烷酮 

分 类 号：TM912[电气工程—电力电子与电力传动]