物理化学学报 >> 2012, Vol. 28 >> Issue (02): 367-372.doi: 10.3866/PKU.WHXB201112131

电化学和新能源 上一篇    下一篇

活性炭基Li2SO4水系电解液超级电容器

孙现众, 张熊, 张大成, 马衍伟   

  1. 中国科学院电工研究所, 北京 100190
  • 收稿日期:2011-10-11 修回日期:2011-12-07 发布日期:2012-01-11
  • 通讯作者: 马衍伟 E-mail:ywma@mail.iee.ac.cn
  • 基金资助:

    中国科学院知识创新工程重要方向项目(KJCX2-YW-W26), 北京市科技计划项目( Z111100056011007)和国家自然科学基金(21001103,51025726)资助

Activated Carbon-Based Supercapacitors Using Li2SO4 Aqueous Electrolyte

SUN Xian-Zhong, ZHANG Xiong, ZHANG Da-Cheng, MA Yan-Wei   

  1. Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China
  • Received:2011-10-11 Revised:2011-12-07 Published:2012-01-11
  • Contact: MA Yan-Wei E-mail:ywma@mail.iee.ac.cn
  • Supported by:

    The project was supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (KJCX2-YW-W26), Science and Technology Project of Beijing, China (Z111100056011007), and National Natural Science Foundation of China (21001103, 51025726).

摘要: 采用中性Li2SO4水溶液代替H2SO4和KOH作为电解液制备了活性炭(AC)基对称型超级电容器, 使水系超级电容器的工作电压由1.0 V提高到了1.6 V. 采用循环伏安和充放电测试研究了电容器的稳定电化学窗口.电化学充放电测试表明电容器在0.25 A·g-1电流密度下单电极比容量可达129 F·g-1, 在功率密度为160 W·kg-1时能量密度达到10 Wh·kg-1 (以正负极活性物质的总质量计). 1.6 V恒压充电1 h 后电容器漏电流为0.22mA. 超级电容器的库仑效率接近100%, 充放电循环5000 次后容量仍可保持在92%以上. 研究了电解液的浓度对电容器电化学性能的影响, 发现随着Li2SO4浓度的增大电容器的电荷转移电阻显著减小, 大电流充放电性能提高. 活性炭基Li2SO4水系电解液超级电容器具有工作电压高、能量密度高和对环境友好等优点, 因此有很好的产业化前景.

关键词: 超级电容器, 活性炭, 中性水系电解液, Li2SO4

Abstract: In this work, we prepared activated carbon-based symmetric supercapacitors using Li2SO4 aqueous electrolyte instead of H2SO4 and KOH, and obtained devices with an improved working voltage of 1.6 V from 1.0 V. Cyclic voltammetry and galvanostatic charging/discharging measurements were used to study the electrochemical properties. The results showed that the electrode specific capacitance can reach 129 F·g-1, and the energy density can be as high as 10 Wh·kg-1 at a power density of 160 Wh·kg-1. Electrochemical impedance analysis measurements showed that the charge-transfer resistance of the capacitors decreased markedly with the increase of the concentration of Li2SO4, and the rate capability improved accordingly. The leakage current of the supercapacitor was 0.22 mA after constant-voltage charging at 1.6 V for 1 h, and the columbic efficiency was nearly 100%. The capacitance of the supercapacitor remained above 90% after 5000 charge-discharge cycles. Activated carbon-based supercapacitors using Li2SO4 aqueous electrolyte have many advantages, such as high working voltage, high energy density, and environmental compatibility, and therefore have good industrialization prospects.

Key words: Supercapacitor, Activated carbon, Neutral aqueous electrolyte, Li2SO4

MSC2000: 

  • O646