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化学学报
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化学学报 ›› 2000, Vol. 58 ›› Issue (9): 1090-1094. 上一篇    下一篇

研究论文

锂离子二次电池正极材料 Li~0~.~7~5Na~0~.~2~5MnO~1~.~9~2I~0~.~0~8化合物 的合成与表征

刘兴泉;陈召勇;刘培松;李庆;于作龙   

  1. 中国科学院成都有机化学研究所.成都(610041);中国科学院功能材料研究开发 中心
  • 发布日期:2000-09-15

Synthesis and characterization of Li~0~.~7~5Na~0~.~2~5MnO~1~. ~9~2I~0~.~0~8 a cathode material for lithium-ion secondary batteries

Liu Xingquan;Chen Zhaoyong;Liu Peisong;Li Qing;Yu Zuolong   

  1. Chengdu Inst Organ Chem, CAS.Chengdu(610041)
  • Published:2000-09-15

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采用LiOH·H~2O为锂源，化学纯MnO~2(CMD)为锰源，NaI为添加剂，乙腈为非水介质，在常温常压下合成了锂离子二次电池正极材料Li~0~.~7~5Na~0~.~2~5MnO~1~.~9~2I~0~.~0~8化合物，并采用XRD，BET，TEM及电化学测试等手段对该化合物进行了表征。结果表明该化合物原料呈非晶态超细粉末，平均粒径在45～60nm之间，具有较大的比表面积(35～48m^2/g)。经260℃真空干燥后，样品转化为纳米晶态，以该化合物作正极材料与Li作对电极构成的锂电池，在1.5～4.3V之间和0.353mA/cm^2条件下恒流充放电，首次充放电比容量超过280(mA·h)/g。充放电效率大于95％。循环20次后，其充放电比容量仍大于260(mA·h)/g，是很有应用前景的锂离子二次电池正极材料。

关键词: 锂离子, 电池, 氢氧化锂, 二氧化锰, Ｘ射线衍射分析, 透射电子显微术

The positive electrode (cathode) material Li~0~.~7~5Na~0~.~2~5MnO~1~. ~9~2I~0~.~0~8 for lithium-ion secondary batteries was synthesized using LiOH as the Li source, MnO~2 as the Mn source, NaI as an additive, and acetonitrile as non-aqueous solvent at room temperature under atmospheric pressure, and was characterized by XRD, BET and TEM as well as electrochemical testing. The results have demonstrated that Li~0~.~7~5Na~0~.~2~5MnO~1~.~9~2I~0~.~0~8 as-synthesized compound is amorphous ultrafine powder with the mean diameter being approximately 45～60nm. Li~0~.~7~5Na~0~.~2~5MnO~1~.~9~2I~0~.~0~8 has a large specific surface area (about 35～48m^2/g). After dried at 260 ℃ in vacuum, the sample was transformed into nano-sized crystals, The results of electrochemical studies have revealed that when this dried compound as cathode material and the lithium metal was used as counter-electrode material to compose of a lithium cell, and charged/discharged with a stable current under the conditions of 1.5～ 4.3V range and 0.353mA/cm^2, the first charge and discharge specific capacity was more than 280(mA·h)/g, and the discharge/charge ratio was more than 95%. After 20 cycles, the charge and discharge specific capacity was also more than 260(mA·h)/g. Therefore, this compound is a cathode material for lithium-ion secondary batteries with remarkable application prospects.

Key words: LITHIUM ION, BATTERIES, LITHIUM HYDROXIDE, MANGANESE DIOXIDE, X-RAY DIFFRACTION ANALYSIS, TRANSMISSION ELECTRON MICROSCOPY

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