ENERGY MANAGEMENT & STORAGE LAB
YEUNGNAM UNIVERSITY

International

  • home
  • PUBLICATION
  • International
Competition between ionic adsorption and desorption on electrochemical double layer capacitor electrodes in acetonitrile solution at different currents and temperatures
Year of publication 2017
Title of paper Competition between ionic adsorption and desorption on electrochemical double layer capacitor electrodes in acetonitrile solution at different currents and temperatures
Authors Park, S., Kang, S.-W., and Kim, K.
Volume 372
Pages 8 - 15
Journal Journal of Power Sources
Link 관련링크 http://dx.doi.org/10.1016/j.jpowsour.2017.10.047 55회 연결
The operation of electrochemical double layer capacitors at high currents and viscosities and at low temperatures is difficult. Under these conditions, ion transport is limited, and some of the electrode area is unavailable for adsorption, which results in a low capacitance. Increasing the temperature helps to increase the ionic movement, leading to enhanced adsorption and increased capacitance. In contrast, ion desorption (self-discharge) surpasses the capacitance improvement when ions gain a high amount of energy with increasing temperature. For example, temperatures as high as 70 °C cause a very high rate of ionic desorption in acetonitrile solutions in which the individual properties of the two electrolytes—tetraethylammonium tetrafluoroborate (TEA BF4) and ethylmethylimidazolium tetrafluoroborate (EMI BF4)—are not distinguishable. The capacitance improvement and self-discharge are balanced, resulting in a capacitance peak at mid-range temperatures, i.e., 35–45 °C, in the more viscous electrolyte, i.e., TEA BF4. The less viscous electrolyte, i.e., EMI BF4 has a wider capacitance peak from 25 to 45 °C and higher capacitance than that of TEA BF4. Because the maximum power is obtained in the mid-temperature range (35–45 °C), it is necessary to control the viscosity and temperature to obtain the maximum power in a given device.