锂离子电池正极材料LiNi_(0.75-x)Co_xMn_(0.25)O_2的合成及电化学性能研究  

Synthesis and Electrochemical Properties of LiNi_(0.75-x)Co_xMn_(0.25)O_2 as Cathode Materials for Li-ion Batteries

作　　者：袁超群[1] 李道聪[1] 沈玉芳[1] 彭正合[1] 周运鸿[1] 

机构地区：[1]武汉大学化学与分子科学学院,武汉430072

出　　处：《无机化学学报》2006年第9期1645-1650,共6页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金资助项目(No.29771025);国家九五重点攻关项目(No.29833090)。

摘　　要：以LiOH·H2O、Ni(OAc)2·4H2O、Co(OAc)2·4H2O和MnO2为原料,在水热反应釜中预处理,然后进行高温固相反应,合成了一系列锂镍钴锰氧化物LiNi0.75-xCoxMn0.25O2(x=0.05,0.10,0.15,0.20,0.25)。通过X射线衍射(XRD)、扫描电子显微镜(SEM)和电化学性能测试对所得样品的结构、形貌、粒径及电化学性能进行了表征。结果表明,当x=0.20时,所合成的正极材料具有很好的α-NaFeO2型层状晶体结构,晶胞参数a=0.2861nm,c=1.4164nm,V=0.1004nm3,以50mA·g-1的电流密度在3～4.3V(vsLi/Li+)充放电时,首次放电比容量达172.5mAh·g-1,首次放电效率高达90.9%,30个循环后其放电比容量依然保持在161.1mAh·g-1。LiNi0.75-xCoxMn0.25O2 （x=0.05, 0.10, 0.15, 0.20, 0.25） compounds were synthesized from LiOH·H2O, Ni （OAc）2·4H2O, Co （OAc）2·4H2O and MnO2. The starting materials were pre-treated in an autoclave and then calcined at 730℃ under flowing oxygen. The products were analyzed by X-ray diffraction spectroscopy（XRD）, scanning electron microscopy （SEM） and electrochemical tests. XRD results showed that all samples were of layered α-NaFeO2 （space group R^-3m） structure. The initial discharge capacities were all more than 160 mAh·g^-1 in the voltage range of 3-4.3 V （vs Li/Li^＋） and all samples had good cyclic performance. LiNi0.55Co0.20Mn0.25O2 exhibited the best electrochemical properties in the five compounds. It showed an initial discharge capacity of 172.5 mAh· g^-1 and remained 161.1 mAh·g^-1 after 30 cycles.

关 键 词：LiNi0.75-xCoxMn0.25O2 锂离子电池 正极材料 电化学性能 

分 类 号：O614.111[理学—无机化学] O614.81[理学—化学]