水热法制备富锂型Li_(2+4x)Mn_(0.6+2x)Ni_(0.6-6x)Cr_(0.8)O_4及其结构与电化学特性  

Structure and Electrochemical Properties of Li-rich Li_(2+4x)Mn_(0.6+2x)Ni_(0.6-6x)Cr_(0.8)O_4 Spinel Prepared by Hydrothermal Method

作　　者：赵利芳[1] 张茜[2] 贺诗词 刘伟伟[2] 杨裕生[4] 郑军伟[2] 潘勤敏[1] 李德成[2] 

机构地区：[1]苏州大学材料与化学化工学部,苏州215123 [2]苏州大学江苏省锂离子电池材料重点实验室化学电源研究所,苏州215006 [3]安徽省阜阳市产品质量监督检验所,阜阳236000 [4]北京防化研究院,北京100083

出　　处：《高等学校化学学报》2014年第2期362-367,共6页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:20973200)资助~~

摘　　要：采用水热法制备了系列富锂尖晶石型正极材料Li2+4xMn0.6+2xNi0.6-6xCr0.8O4(x=1/30,1/20,1/15,1/12),通过X射线衍射(XRD)、电感耦合等离子体-原子发射光谱(ICP-AES)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、傅里叶变换红外光谱(FTIR)、拉曼光谱、循环伏安(CV)和充放电测试等手段对其结构及电化学性能进行表征.结果表明,所制备的系列材料为富锂型高电压尖晶石结构正极材料,该系列样品在4.7 V左右有放电平台.x=1/15和x=1/12时,样品中的Cr为+3价,没有观测到Cr6+.随着x值的增大,样品中Li离子与过渡金属离子的混排减小,样品的充放电比容量逐渐增大,且2.7 V处的放电平台容量也增加.当x=1/12时,样品具有较好的充放电比容量和倍率特性,首次放电比容量为107.3 mA·h/g,20次循环后容量保持率为84.9%.A series of cathode materials, Li2＋4xMn0.6＋2xNi0.6-6xCr0.8O4（x=1/30, 1/20, 1/15, 1/12）, was prepared via hydrothermal method, and their composition, structure and electrochemical properties were inves-tigated using X-ray diffraction（XRD）, inductively coupled plasma-atomic emission spectrometry（ICP-AES）, scanning electron microscopy （ SEM ） , X-ray photoelectron spectroscopy （ XPS ） , Fourier transform infrared spectrometry （ FTIR ） , Raman spectrometry and charge-discharge tests. XRD measurements combining with ICP results reveal that the obtained samples are Li-rich type spinel structure. Moreover, XPS results suggest that the valence for Cr is＋3 for x=1/15 and 1/12 and no Cr6＋exist. As to their electrochemical properties, it is found that these materials have a high-voltage plateau near 4.7 V and a low-voltage near 2.7 V. With the increase of x value, both charge and discharge capacities of the samples increase. The sample with x=1/12 shows a good cyclic performance as well as good rate capability.

关 键 词：锂离子电池 正极材料 富锂尖晶石结构 水热法 高电压 

分 类 号：O646[理学—物理化学] O614.111[理学—化学]