4.7 Article

Triethylammonium thiocyanate ionic liquid electrolyte-based supercapacitor fabricated using coconut shell-derived electronically conducting activated charcoal electrode material

Journal

JOURNAL OF ENERGY STORAGE
Volume 55, Issue -, Pages -

Publisher

ELSEVIER
DOI: 10.1016/j.est.2022.105628

Keywords

Activated carbon; Supercapacitor; Triethylammonium thiocyanate; Ionic liquid electrolyte

Categories

Ask authors/readers for more resources

Organic solvents are commonly used in supercapacitors as electrolytes, but their drawbacks include high volatility, toxicity, and environmental issues. In this study, a novel and low-cost ionic liquid based on triethylammonium cation and thiocyanate anion was synthesized and used as the electrolyte in a low-cost supercapacitor. The electrode material used was electronically conducting activated carbon derived from cleaned coconut shells. The temperature dependence of electrolyte conductivity was investigated, and the ion transport kinetics behaved according to the Vogel-Tammann-Fulcher (VTF) model. The optimized electrode fabrication method resulted in the highest specific capacitance in the supercapacitor assembly.
Organic solvents are commonly used as commercial electrolytes in supercapacitors, but they have several drawbacks, such as high volatility, toxicity, and environmental issues. To overcome these problems, ionic liquids are used though their high costs hamper commercial applications. In this study, a novel and low-cost ionic liquid based on triethylammonium cation and thiocyanate anion were synthesized and used as the electrolyte in a low-cost supercapacitor fabricated using electronically conducting activated carbon derived from cleaned coconut shells as electrode material. The temperature dependence of electrolyte conductivity was investigated, in the frequency range of 1 Hz-500 kHz, using AC impedance analysis, in the temperature range from 30 degrees C -90 degrees C in ten-degree increments and found to be in the range of 4.5 to 14.4 mS cm- 1. The ion transport kinetics behaves according to the Vogel-Tammann-Fulcher (VTF) model with an activation energy (Ea) and the pre-exponential factor (A sigma T) of 0.0158 eV and 114.9 S m-1 K1/2, respectively. The activated carbon material developed has a high porosity and high electronic conductivity. The electrode fabrication methodology was optimized by varying the polyvinylpyrrolidone (PVP) binder amount with respect to the mass of activated carbon on a titanium sheet as a function of heat treatment temperature. The supercapacitor that gives the highest specific capacitance is based on the electrode constructed using 5 % w/w PVP in 0.50 g of activated carbon deposited on a titanium sheet by heat treating at 200 degrees C for 20 min. At the scan rate of 5 mV s- 1, two-electrode CV studies revealed a specific capacitance of 36.8 F g-1 for the optimized supercapacitor assembly. The electrolyte triethylammonium thiocyanate (TAT) demonstrated good electrochemical stability and a large operating voltage window of 1.8 V and high stability, with 94.4 % capacity retention after 1000 cycles. The AC impedance studies also gave comparable results. Prime novelty statement: The manuscript describes a method to prepare a novel and low-cost ionic liquid material triethylammoniumthiocyanate starting from triethylamine and ammonium thiocyanate, and its application as the ionic liquid electrolyte in a low-cost supercapacitor. The electrode material used in the supercapacitor was fabricated using electronically conducting activated carbon derived from cleaned coconut shells, which were deposited firmly adhering to titanium sheets using polyvinylpyrrolidone binder under optimized heat treatment conditions. As such, both the ionic liquid electrolyte and the activated carbon electrode material are novel and attractive materials for the commercial production of low-cost supercapacitors.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.7
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available