Double-layer capacitors (DLCs) are developed with high surface electrodes to achieve a high capacitance value. In the present work, the initial bulk concentration of 1 mol/m3 and 3 mol /m3 are selected to show the consequential effects on the performance of a double-layer capacitor. A 1D model of COMSOL Multiphysics has been developed to analyze the electric field and potential in cell voltage, the electric displacement field and polarization induced by the field, and energy density in a double-layer structure. The electrostatics and the electric circuit modes in COMSOL are used to simulate the electrochemical processes in the double-layer structure. The analytical analysis of a double-layer capacitor with different initial bulk concentrations is investigated by using Poisson-Nernst-Plank equations. From the simulation results, the differential capacitance changes as a function of compact layer thickness and initial bulk concentration. The energy density varies with the differential capacitance and voltage window. The values of energy density are dominated by the interaction of ions in the solution and electrode surface.

Abstract
1. Introduction
2. Design and Methods
    2.1. Design Parameters for Double-Layer Capacitors
    2.2. Model Equation for Double-Layer Capacitors
    2.3. Electroanalysis
    2.4. COMSOL Multiphysics
3. Result and Discussion
    3.1. Effect of bulk concentration on the electric field
    3.2. Effect of bulk concentration on polarization
    3.3. Effect of bulk concentration on the electricdisplacement field
    3.4. Effect of bulk concentration on the energydensity
4. Conclusions
Acknowledgement
Nomenclature
References
Author Information

• Khaing Nee Nee Khaing(Department of Electronics Engineering, Mandalay Technological University) Corresponding author
• Tin Tin Hla(Department of Electronics Engineering, Mandalay Technological University)