Engineering the Electrochemical Capacitive Properties of Activated Carbon by Correct Selection of Ionic-Liquid Electrolytes

Authors

Qiu-hong ZHANG, Jiangsu Key Laboratory of Biomass-based Green Fuels and Chemicals, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037,China;
Bao-shou SHEN, Jiangsu Key Laboratory of Biomass-based Green Fuels and Chemicals, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037,China;
Song-lin ZUO, Jiangsu Key Laboratory of Biomass-based Green Fuels and Chemicals, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037,China;Follow
Xin-yu WEI, Jiangsu Key Laboratory of Biomass-based Green Fuels and Chemicals, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037,China;

Corresponding Author

Song-lin ZUO(zslnl@njfu.com.cn)

Abstract

In order to improve the electrochemical capacitive properties and to apply coconut shell activated carbon (AC) serving as electrode materials in ionic liquid (IL)-based supercapacitor (SC), the coconut shell AC material was re-activated using a steam as an activating agent in this work, forming a secondary AC (W-AC). The results showed that the specific capacitance of the W-AC electrode was much larger than that of the raw activated carbon electrode (R-AC) in 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM]BF₄). The electrochemical techniques including cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) measurement, and electrochemical impedance spectroscopy (EIS) were used to systematically study the capacitive properties of W-AC electrode in a series of ILs composed of different cations and anions. The electrochemical performances of the W-AC electrode using different ILs as electrolytes varied because of the different ion diameters, liquid viscosities and ionic conductivities for various ILs. Among them, the IL electrolytes composed of EMIM+, BMIM⁺ and BF₄^-, TFSI- were found to be most suitable for W-AC electrode. The specific capacitance of W-AC electrode reached 153 F•g^-1 in [EMIM]BF4 IL electrolyte, and the as–assembled SCs could achieve a high energy density of 57 Wh•kg^-1 with a potential window of 3.5 V in [BMIM]BF₄. These results may provide valuable information for selecting appropriate ionic liquids and designing high-performance supercapacitors to meet different needs.

Graphical Abstract

DOI Link

https://doi.org/10.13208/j.electrochem.161215

Publication Date

2017-12-28

Online Available Date

2017-03-01

Revised Date

2017-03-01

Received Date

2016-12-15

Recommended Citation

Qiu-hong ZHANG, Bao-shou SHEN, Song-lin ZUO, Xin-yu WEI. Engineering the Electrochemical Capacitive Properties of Activated Carbon by Correct Selection of Ionic-Liquid Electrolytes[J]. Journal of Electrochemistry, 2017 , 23(6): 684-693.
DOI: 10.13208/j.electrochem.161215
Available at: https://jelectrochem.xmu.edu.cn/journal/vol23/iss6/6