Evaluating the Electrochemical Properties of Supercapacitors using the Three-Electrode System

Summary

The protocol describes the evaluation of various electrochemical properties of supercapacitors using a three-electrode system with a potentiostat device.

Abstract

The three-electrode system is a basic and general analytical platform for investigating the electrochemical performance and characteristics of energy storage systems at the material level. Supercapacitors are one of the most important emergent energy storage systems developed in the past decade. Here, the electrochemical performance of a supercapacitor was evaluated using a three-electrode system with a potentiostat device. The three-electrode system consisted of a working electrode (WE), reference electrode (RE), and counter electrode (CE). The WE is the electrode where the potential is controlled and the current is measured, and it is the target of research. The RE acts as a reference for measuring and controlling the potential of the system, and the CE is used to complete the closed circuit to enable electrochemical measurements. This system provides accurate analytical results for evaluating electrochemical parameters such as the specific capacitance, stability, and impedance through cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). Several experimental design protocols are proposed by controlling the parameter values of the sequence when using a three-electrode system with a potentiostat device to evaluate the electrochemical performance of supercapacitors. Through these protocols, the researcher can set up a three-electrode system to obtain reasonable electrochemical results for assessing the performance of supercapacitors.

Introduction

Supercapacitors have attracted enormous attention as suitable power sources for a variety of applications such as microelectronic devices, electric vehicles (EVs), and stationary energy storage systems. In EV applications, supercapacitors can be used for rapid acceleration and can enable the storage of regenerative energy during the deceleration and braking processes. In renewable energy fields, such as solar power generation¹ and wind power generation², supercapacitors can be used as stationary energy storage systems^3,4. Renewable energy generation is limited by....

Protocol

1. Fabrication of electrode and supercapacitor (Figure 1)

1. Prepare the electrodes prior to the electrochemical analysis by combining 80 weight (wt)% of the electrode active material (0.8 g activated carbon), 10 wt% of the conductive material (0.1 g carbon black), and 10 wt% of the binder (0.1 g polytetrafluoroethylene (PTFE)).
   1. Drop isopropanol (IPA; 0.1-0.2 mL) into the above-mentioned mixture, then spread the mixture thinly into a dough with a roller.
2. Before attaching the electrode to stainless steel (SUS) mesh, cut the SUS mesh to dimensions of 1.5 cm (widt....

Results

The electrodes were manufactured according to protocol step 1 (Figure 1). Thin and homogeneous electrodes were attached to SUS mesh with a size of 1 cm² and 0.1-0.2 mm thickness. After drying, the weight of the pure electrode was obtained. The electrode was immersed in a 2 M H₂SO₄ aqueous electrolyte, and the electrolyte was allowed to sufficiently permeate the electrode before the electrochemical analyses. The production sequence and system setting for the e.......

Discussion

This study provides a protocol for various analyses using a three-electrode system with a potentiostat device. This system is widely used to evaluate the electrochemical performance of supercapacitors. A suitable sequence for each analysis (CV, GCD, and EIS) is important for obtaining optimized electrochemical data. Compared with the two-electrode system having a simple setup, the three-electrode system is specialized for analyzing supercapacitors at the material level¹⁵. However, the selection of.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Activated carbon	GS		Active material
Ag/AgCl electrode	BASi	RE-5B	Reference electrode
Carbon black	Hyundai		Conductive material
Desicator	Navimro
Electrode pressing machine	Rotech
Extractor	WonA Tech		Convert program (raw data to excel form)
Isopropanol(IPA)	Samchun	I0346	Solvent to melt the binder
Polytetrafluoroethylene(PTFE)	Hyundai		Binder
Potentiostat	WonA Tech	Zive SP1
Pt electrode	BASi	MW-018122017	Counter electrode
Reaction flask	Duran		Container for electrolyte
SM6	WonA Tech		Program of setting sequence and measuring electrochemical result
Sulfuric acid	Samshun	S1423	Electrolyte
SUS mesh	Navimro		Current collector
Teflon cap	WonA Tech		Cap of the electrolyte continer
Zman	WonA Tech		EIS program