复合掺杂改性LiMn_(2-x)Cr_xO_(4-3x)F_(3x)正极材料的制备及性能  

SYNTHESIS AND CHARACTERIZATION OF CO-DOPING MODIFIED SPINEL LiMn_(2-x)Cr_xO_(4-3x)F_(3x) AS CATHODE MATERIALS

作　　者：禹筱元[1] 余仕禧[1] 周武艺[1] 胡国荣[2] 刘业翔[2] 

机构地区：[1]华南农业大学理学院生物材料研究所,广州510642 [2]中南大学冶金科学与工程学院,长沙410083

出　　处：《硅酸盐学报》2010年第6期1053-1058,共6页Journal of The Chinese Ceramic Society

基　　金：广东省自然科学基金(9151064201000039);广东省科技计划(2009B010900025);校"211工程"(2009B010100001)资助项目

摘　　要：以CrF3为掺杂原料,采用高温固相法合成阴阳离子共掺杂LiMn2–xCrxO4–3xF3x锂离子电池正极材料。用X射线衍射、扫描电镜、充放电实验、循环伏安及交流阻抗等表征材料的结构、形貌和电化学性能,分析阴阳离子复合掺杂对材料结构和性能的影响。结果表明:掺杂材料LiMn2–xCrxO4–3xF3x具有完整的尖晶石结构。阴阳离子复合掺杂能改善尖晶石LiMn2O4的循环性能,当摩尔掺量x=0.10,电压为3.0～4.35V、充放电倍率为0.1C时,首次放电容量为120.1mA·h/g,室温、高温循环20次容量保持率分别为97.5%和94.1%。循环伏安实验发现:复合掺杂改性材料具有两对更完整、对称性更好的氧化还原峰。Co-doping modified spinel LiMn2–xCrxO4–3xF3x cathode materials for lithium ion battery were synthesized by the high tem-perature solid-state reaction method,utilizing CrF3 as co-doping reagent. The X-ray diffraction,scanning electron microscope charge/discharge tests,cyclic voltammetry,and electrochemical impedance spectroscopy were used to analyze structure,surface morphology and electrochemical performances of LiMn2–xCrxO4–3xF3x materials. Effects of co-doping modification on the structure and electrochemical properties were also investigated. The results show that LiMn2–xCrxO4–3xF3x materials have pure spinel structure and exhibit good cycle performance. The LiMn2–xCrxO4–3xF3x （x = 0.10） cathode material has an initial capacity of 120.1 mA·h/g at a current rate of 0.1 C and a voltage window of 3.0–4.35 V,and its capacity retain 97.5% and 94.1% after cycling 20 times at room tem-perature and elevated temperature （55 ℃）,respectively. The cyclic voltammetry results indicate that the shape of two couples of re-dox peaks of the co-doping modification material is more integrate and symmetrical than that of the pure spinel LiMn2O4.

关 键 词：锂离子电池 尖晶石锂锰氧化物 电化学性能 共掺杂改性 正极材料 

分 类 号：TM912.9[电气工程—电力电子与电力传动]