Related Experiment Video
Updated: Jun 16, 2026

Evaluating the Electrochemical Properties of Supercapacitors using the Three-Electrode System
Published on: January 7, 2022
Does Electrode Spacing Truly Control Capacitance and Energy Density in Graphene-Based Supercapacitors? A Molecular
Davi de Oliveira Guedes1, Henrique de Araujo Chagas1, Iuliia V Voroshylova2
1Instituto de Física, Universidade Federal de Goiás, Goiânia, Goiás 74690-900, Brazil.
Abstract:
Electrode spacing is frequently considered a parameter in supercapacitor optimization, yet its intrinsic impact on capacitance and energy storage under nanoconfinement remains uncertain. In this study, classical molecular dynamics simulations were performed for graphene-based supercapacitors containing the ionic liquid [emim]-[ala] confined between planar electrodes separated by 4-12 nm. Electric potential profiles enabled the calculation of differential and total capacitances as well as stored energy densities. Mass density analyses show well-defined electric double layers (EDLs) at both electrodes. Strong overlap is observed at short separations, whereas a bulk-like central region is preserved at larger ones. Nevertheless, the total capacitance remains nearly constant (∼2.40-2.58 μF/cm2), and the differential capacitance at zero charge varies only slightly across all separations, indicating a surface-dominated storage mechanism. The integrated areal energy density up to 2.5 V is also essentially independent of spacing (∼7.4-7.7 μJ/cm2). In contrast, gravimetric and volumetric energy densities decrease with increasing separation due to mass and volume normalization effects. These results demonstrate that electrode spacing modulates EDL structure but only weakly affects intrinsic capacitive performance.
Related Concept Videos
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 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...
Energy Stored in a Capacitor
Capacitors and Capacitance
When the conductors are two identical parallel plates, it is called a parallel plate capacitor. When battery terminals are...
Equivalent Capacitance
The following strategies are adopted to calculate...
Equivalent Capacitance
