Related Experiment Video
Updated: Aug 13, 2025

Evaluating the Electrochemical Properties of Supercapacitors using the Three-Electrode System
Published on: January 7, 2022
Exploration of Charge Storage Behavior of Binder-Free EDL Capacitors in Aqueous Electrolytes
Bhupender Pal1, Kalyan Jyoti Sarkar1, Bing Wu1
1Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technicka 5, 166 28 Prague 6, Czech Republic.
Abstract:
Charge storage in electrochemical double-layer capacitors (EDLCs) is via the adsorption of electrolyte counterions in their positive and negative electrodes under an applied potential. This study investigates the EDLC-type charge storage in carbon nanotubes (CNT) electrodes in aqueous acidic (NaHSO4), basic (NaOH), and neutral (Na2SO4) electrolytes of similar cations but different anions as well as similar anions but different cations (Na2SO4 and Li2SO4) in a two-electrode Swagelok-type cell configuration. The physicochemical properties of ions, such as mobility/diffusion and solvation, are correlated with the charge storage parameters. The neutral electrolytes offer superior charge storage over the acidic and basic counterparts. Among the studied ions, SO4 2- and Li+ showed the most significant capacitance owing to their larger solvated ion size. The charge stored by the anions and cations follows the order SO4 2- > HSO4 - > OH- and Li+ > Na+, respectively. Consequently, the CNT//Li2SO4//CNT cell displayed outstanding charge storage indicators (operating voltage ∼0-2 V, specific capacitance ∼122 F·g-1, specific energy ∼67 W h·kg-1, and specific power ∼541 W·kg-1 at 0.5 A·g-1) than the other cells, which could light a red light-emitting diode (2.1 V) for several minutes. Besides, the CNT//Li2SO4//CNT device showed exceptional rate performance with a capacitance retention of ∼95% at various current densities (0.5-2.5 A·g-1) after 6500 cycles. The insights from this work could be used to design safer electrochemical capacitors of high energy density and power density.
More Related Videos
08:59Synthesizing a Gel Polymer Electrolyte for Supercapacitors, Assembling a Supercapacitor Using a Coin Cell, and Measuring Gel Electrolyte Performance
Published on: November 30, 2022
12:28Non-aqueous Electrode Processing and Construction of Lithium-ion Coin Cells
Published on: February 1, 2016
Related Concept Videos
Dielectric Polarization in a Capacitor
Energy Stored in Capacitors
By integrating the equation that relates voltage and current in a capacitor, one can derive an equation for the voltage across the capacitor at any given time. This equation is crucial in understanding and predicting the behavior of capacitors in...
Capacitor With A Dielectric
Dielectrics are non-conducting materials with no free or loosely bound electrons. When a dielectric is...
MOS Capacitor
The metal gate is typically made from highly conductive materials such as aluminum or polysilicon. Beneath the metal gate lies a thin layer of...
Energy Stored in a Capacitor
Energy Stored in a Capacitor: Problem Solving
Capacitor-discharge ignition is a type of ignition system commonly found in small engines where the energy released from a capacitor ignites an induction coil that, in turn, fires the spark plug.
To calculate the energy stored in a capacitor of...