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化学学报
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化学学报 ›› 2007, Vol. 65 ›› Issue (17): 1911-1916. 上一篇    下一篇

研究论文

不同工作介质下二氧化锰/膨胀石墨复合材料的电化学电容器行为

万传云*,1, Kazuhisa AZUMI2, Hide-taka KONNO2   

  1. (1上海应用技术学院化学工程系 上海 200235)
    (2 Laboratory of Advanced Materials Chemistry, Graduate School of Engineering, Hokkaido University,
    Sapporo, 060-8628 Japan)
  • 投稿日期:2006-11-02 修回日期:2007-04-25 发布日期:2007-09-14
  • 通讯作者: 万传云

Behavior of Manganese Dioxide/Exfoliated Graphite Composite as Materials for Electrochemical Capacitor in Different Electrolytes

WAN Chuan-Yun*,1; AZUMI Kazuhisa2; KONNO Hide-taka2   

  1. (1 Department of Chemical Engineering, Shanghai Institute of Technology, Shanghai 200235, China)
    (2 Laboratory of Advanced Materials Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan)
  • Received:2006-11-02 Revised:2007-04-25 Published:2007-09-14
  • Contact: WAN Chuan-Yun

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760

被引次数

20 | 4

研究了氧化还原法制备二氧化锰/膨胀石墨复合材料用作电化学电容器, 利用热重分析、比表面及X射线衍射方法对材料的组成及结构进行了表征, 利用三电极循环伏安及充放电循环法研究了材料在硫酸钠、氯化钠、氯化钾及硝酸钾不同电解质中的电化学行为. 研究结果表明, 二氧化锰以非晶态的形式在复合材料中存在, 膨胀石墨起良好电导作用, 随其用量的增加, 复合材料的比表面下降, 但二氧化锰的比电容增加. 不同工作介质中电化学行为显示, 复合材料电化学行为的不同主要跟阳离子的种类有关. 在钠离子电解质中, 复合材料电极体现较高的表观电容和真实电容, 在钾盐电解质体系中, 复合材料电极的电流响应速度比较快, 这是由于钠盐和钾盐溶液具有不同的水合数、水合半径和电导率. 当复合材料中膨胀石墨的用量为24%左右时, 复合材料在2 mV/s扫描速度下, 在1 mol/L Na2SO4溶液中体现的比电容为220 F/g, 复合材料显示优良的循环性能.

关键词: 二氧化锰, 膨胀石墨, 复合材料, 电化学电容器

Manganese dioxide/exfoliated graphite composite as materials for electrochemical capacitor was synthesized using a redox reaction. The synthesized product was characterized using thermogravimetric analysis, nitrogen adsorption-desorption (BET) method, and X-ray diffraction. Electrochemical characterization was performed by cyclic voltammetry using a three-electrode setup and also by constant current charge-discharge method. Aqueous Na2SO4, NaCl, KCl and KNO3 solutions were used as electrolytes. The results showed that the structure of manganese dioxide in composite was amorphous and the exfoliated graphite (EG) functioned to give good conductivity. The capacitances of the manganese dioxide increased with increasing amount of EG, while the BET surface area of the composites decreased. The electrochemical behavior of the MnO2/EG composite electrode in different electrolytes suggested that cation species mainly affect the electrochemical performance. The charge from the accessible total sites (QT) and the apparent charge in Na＋-containing electrolyte are larger than those in K＋-containing electrolytes while a good current response could be found in K＋-containing electrolytes due to their different hydration number, hydrated radius and ion conductivity. The optimized sample, MnO2/EG24, exhibited a specific capacitance of around 220 F/g in 1 mol/L Na2SO4 solution at 2 mV/s scan rate with a good cycleability.

Key words: manganese dioxide, exfoliated graphite, composite, electrochemical capacitor