Energy Storage Science and Technology ›› 2021, Vol. 10 ›› Issue (2): 491-496.doi: 10.19799/j.cnki.2095-4239.2020.0339

• Energy Storage Materials and Devices • Previous Articles     Next Articles

Study on effect of an asymmetric design of the mass on the cathode and anode on supercapacitor performance

Rui FENG1(), Hai LU1(), Xinyi LIU1, Hao LI2, Xiangyuan LI2   

  1. 1.College of Materials Science and Engineering, Xi'an University of Science and Technology, Xi'an 710054, Shaanxi China
    2.Xi'an Herong New Energy Technology Co. Ltd. , Xi'an 710200, Shaanxi, China
  • Received:2020-10-16 Revised:2020-11-09 Online:2021-03-05 Published:2021-03-05

Abstract:

A series of activated carbon-based supercapacitors were assembled in an electrolyte consisting of ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4) mixed with propylene carbonate (PC) and dimethyl carbonate (DMC) by adjusting the mass ratio of the active materials on the cathode and anode (P/N ratio). The influence of the asymmetric electrode mass design on the overall performance of supercapacitors was investigated through galvanostatic charge/discharge, cyclic voltammetry, and electrochemical impedance spectroscopy. The results show that the oxidation decomposition of the electrolyte at high voltage is restrained. The 3V cycle stability and specific capacitance of the capacitor at low rates are improved by increasing the P/N ratio. However, it also leads to an increase in the discharge voltage drop and equivalent series resistance of the capacitor. The capacitance retention of the capacitor with the P/N ratio of 1.4 is 90.4% after 5000 cycles at 10 mA. Its specific energy and specific power are 9.95 W·h/kg and 4480 W/kg, respectively, at a discharge rate of 50 mA. This reflects better cycle performance but weaker power capability of the asymmetric capacitor than those of the symmetrical one. The research exhibits the merit of the asymmetric electrode structure but points out the difficulty in achieving an improved overall performance of the capacitor.

Key words: supercapacitor, asymmetric, P/N ratio, work voltage, power characteristic

CLC Number: