Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (02): 367-372.doi: 10.3866/PKU.WHXB201112131

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

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
  • 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).

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


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