锰掺杂磷酸铁锂/碳正极材料的制备及电化学性能  

Synthesis of Manganese-Doped Lithium Iron Phosphate/Carbon Composite and Its Electrochemical Performances

作　　者：杨则恒[1] 赵刚[1] 张卫新[1] 

机构地区：[1]合肥工业大学化学工程学院,合肥230009

出　　处：《硅酸盐学报》2011年第10期1608-1612,共5页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(20871038;20976033);安徽省教育厅资助项目(TD200702);国家大学生创新基金(101035925)资助

摘　　要：以MnPO4.H2O、FePO4.2H2O为锰源和铁源,碳酸锂为锂源,葡萄糖为还原剂和碳源,采用高温碳热还原法,一步制备了改性的锂离子电池正极材料LiMn0.45Fe0.55 PO4/C,并讨论了合成温度对材料的影响。采用X射线衍射、扫描电子显微镜和充放电测试等手段,对最终产物的物相、形貌和电化学性能进行了表征。结果表明:在500～600℃可以制备LiMn0.45Fe0.55PO4/C固溶体材料。室温条件下充放电测试表明:600℃制备的LiMn0.45Fe0.55PO4/C具有最好的电化学性能,以15、75 mA/g和150 mA/g进行充放电,首次放电比容量分别为146.6、133.5 mA h/g和124.1 mA h/g,50次循环后容量保持率分别为97.5%、95.8%和97.6%;以300 mA/g的电流密度放电,首次放电比容量达到94.4 mA h/g。材料在55℃时电化学性能明显优于25℃的结果。LiMn0.45Fe0.55 PO4/C, as a cathode material of lithium ion batteries, was prepared with MnPO4H20, FePO2H20 and Li2CO3 as precursors and glucose as both reducing agent and carbon source by one-step carbothermal reduction. The effect of synthesis temperature on the performances of LiMn0.asFe0.55PO4/C composites was investigated. The morphology and microstructure of the products were characterized by X-ray diffraction and scanning electron microscopy. The results show that LiMno.45Feo.55PO4/C solid solution can be prepared from 500 to 600 ℃. As an electrode material for rechargeable lithium ion batteries, the solid solution prepared at 600 ℃ exhibited a superior electrochemical performance. The initial discharge capacity of the sample reached 146.6, 133.5, 124.1 and 94.4 mA＇h/g at the current density of 15, 75, 150 mA/g and 300 mA/g, respectively. In addition, this sample showed a good cycle performance. After 50 cycles it retained 97.5%, 95.8% and 97.6% of the initial discharge capacity at 15, 75 mA/g and 150 mA/g, respectively. It was indicated that the electrochemical performance of the sample at 55℃ was better than that at 25 ℃.

关 键 词：锂离子电池 正极材料 锰掺杂 碳热还原 

分 类 号：TM912[电气工程—电力电子与电力传动]