Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (11): 2071-2076.doi: 10.3866/PKU.WHXB201408292

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Experimental Investigation of Electrochemical Impedance Spectroscopy of Electrical Double Layer Capacitor

SUN Xian-Zhong, HUANG Bo, ZHANG Xiong, ZHANG Da-Cheng, ZHANG Hai-Tao, MA Yan-Wei   

  1. Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China
  • Received:2014-07-28 Revised:2014-08-29 Published:2014-10-30
  • Contact: MA Yan-Wei E-mail:ywma@mail.iee.ac.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (51307167, 51025726).

Abstract:

Electrochemical impedance spectroscopy (EIS) is a very useful technique for studying electrochemical behavior. The ideal Nyquist plot of electrochemical impedance spectroscopy for an electrical double-layer capacitor (EDLC) consists of a 45° line in the high-middle frequency region and a vertical line in the low frequency region, which can be explained by the transmission line model with pore size distribution. However, a semicircle loop in the high frequency region has been found in many studies. Hence, in this study, an equivalent model is proposed, in which the semicircle loop is ascribed to the contact resistance and contact capacitance between particles of activate materials, and between the activated carbon (AC) electrode and current collector. The effects of the charging process, conductivities of the active material and electrolyte, content of conductive additive and binder, porous separator, mass loading, and exerted pressure to the electrode on the EIS spectra of EDLCs were experimentally investigated. Among these effects, the most significant factors were the charging cut-off voltage, conductivity of activated carbon, content of conductive additive, and exerted pressure.

Key words: Electrochemical impedance spectroscopy, Electrical double layer capacitor, Activated carbon, Contact resistance, Contact capacitance

MSC2000: 

  • O646