Sc^(3+)掺杂LiMn_xSc_(1-x)O_2材料的合成及电化学性能研究  

Synthesis and Electrochemical Properties of Sc-doped LiSc_xMn_(1-x)O_2 Orthorhombic Structure Cathode Material for Lithium-ion Batteries

作　　者：粟智[1] 叶世海[2] 王永龙[2] 

机构地区：[1]新疆师范大学生命科学与化学学院,新疆乌鲁木齐830054 [2]南开大学化学学院新能源材料化学研究所,天津300071

出　　处：《中国稀土学报》2009年第6期779-785,共7页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金资助项目(20773070)

摘　　要：采用水热反应的方法,以LiOH.H2O,MnOOH和Sc2O3为原料,合成了一系列Sc3+掺杂的锂离子电池正极材料LiScxMn1-xO2(x=0.01,0.02,0.03,0.05)。利用X射线衍射和X光电子能谱测试研究了材料的结构和元素的化学状态。掺杂后的LiScxMn1-xO2材料仍保持正交相结构。电化学测试结果表明,掺杂后材料表现出较好的电化学性能,Sc3+的掺入使材料的循环稳定性能大幅度提高,掺杂量为2%时LiMn0.981Sc0.019O2材料的初次放电容量为140.5 mAh.g-1,60次循环后放电容量高达169.6 mAh.g-1,远高于未掺杂的LiMnO2材料的放电容量107.7 mAh.g-1。这种提高源于Sc3+的加入,很好地起到了稳定晶体结构、有效抑制Jahn-Teller效应的作用。电化学阻抗测试结果表明,Sc3+的掺入能改善材料的导电性能。A series of Sc3＋-doping layered lithium manganese oxides LiScxMn1-xO2（x=0.01,0.02,0.03 and 0.05） were synthesized by a hydrothermal reaction using LiOH·H2O,MnOOH,and Sc2O3 as starting materials.The structure and the chemical states of elements were analyzed by X-ray diffraction（XRD） and X-ray photoelectron spectra（XPS）.The results indicated that the Sc-doped LiScxMn1-xO2 materials maintained the orthorhombic structure.The electrochemical analyses exhibited better electrochemical properties after Sr3＋-doping,especially,the better cyclic capability.The initial discharge capacity of the doped LiMn0.981Sc0.019O2 material reached 140.5 mAh·g-1,and the discharge capacity after 60 cycles was 169.6 mAh·g-1,which was much higher than that of the undoped LiMnO2 materials（107.7 mAh·g-1 after 60 cycles）.It was due to that Sc3＋ doping effectively restricted Jahn-Teller effect and stabilized the crystal structure of layered LiMnO2.The EIS analysis showed that the conductivity of the as-prepared samples was evidently improved by the Sc3＋ doping.

关 键 词：正交结构LiMnO2 锂离子电池 水热反应 离子掺杂 稀土 

分 类 号：TQ15[化学工程—电化学工业] O61[理学—无机化学]