锂离子电池正极材料Li_2Fe_(0.5)Mn_(0.5)SiO_4/C的制备及电化学性能  

Preparation and Electrochemical Performance of Li_2Fe_(0.5)Mn_(0.5)SiO_4/C Cathode Material for Lithium Ion Batteries

作　　者：胡传跃[1] 郭军[1] 文瑾[1] 彭秧锡[1] 陈艳[1] 

机构地区：[1]湖南人文科技学院化学与材料科学系,娄底417000

出　　处：《材料导报（纳米与新材料专辑）》2012年第1期199-201,共3页

基　　金：湖南省教育厅资助科研项目(10B054);湖南省科技计划项目(2011FJ3160;2011GK2002);湖南省自然科学基金(07JJ6082)

摘　　要：采用液相法合成了锂离子电池Li2Fe0.5Mn0.5SiO4/C正极材料,考察了热处理温度对Li2Fe0.5Mn0.5-SiO4/C电化学性能的影响,运用XRD、SEM、充放电测试方法和循环伏安法表征了Li2Fe0.5Mn0.5SiO4/C的结构和电化学性能。结果表明,合成的Li2Fe0.5Mn0.5SiO4/C晶胞为斜方晶胞结构,属于Pmn21空间群。其中700℃焙烧7h制备的Li2Fe0.5Mn0.5SiO4/C材料具有较好的电化学性能,首次可逆容量为206.2mAh/g,库仑效率为94.9%,循环20次后的可逆容量为145.7mAh/g,Li2Fe0.5Mn0.5SiO4/C中Fe2+/Fe3+和Mn2+/Mn4+电对的氧化峰电位比较接近,均为4.5V(vs Li/Li+),3个还原峰峰电位分别为3.5V、2.9V和2.1V。The cathode material Li2Fe0.5Mn0.5SiO4/C was prepared with solution method. The effect of calcina- tions temperature on the electrochemical performance of Li2Fe0.5Mn0.5SiO4/C was studied. The structure and electro chemical performance of Li2Fe0.5Mn0.5SiO4/C were characterized by XRD, SEM, charge-discharge tests and cyclic vohammogram method. The results show that the crystal structure of all samples is orthorhombic unit cell （space group Pmn21 ）. Li2Fe0.5Mn0.5SiO4/C sample prepared at 700℃ for 7h delivers good electrochemical performance. The initial discharge specific capacity of 1.i2 Feo. s Mm ; SiO4/C is 206.2mAh/g, the Coulomb efficiency is 94.9%, the discharge capacity is 145.7mAh/g after 20 cycles, respectively. The Li2Fe0.5Mn0.5SiO4/C material exhibits a single oxidation peaks at about 4. 5V vs Li/Li＋and three reduction peaks at about 3.5V,2.9Vand 2. IV vs Li/Li＋ .

关 键 词：锂离子电池 正极材料 Li2Fe0.5Mn0.5SiO4/C液相法 

分 类 号：TM912.9[电气工程—电力电子与电力传动]