Simulation Study of Electric Double-Layer Capacitance of Ordered Carbon Electrodes

Abstract

Supercapacitors are electrochemical energy storage devices having high capacitance, high power density, long cycle life, low cost, easy maintenance, and negligible environmental pollution. The formation of an electric double layer at the electrode–electrolyte interface is mostly responsible for supercapacitors’ energy storage. The simulation study of equilibrium electric double-layer capacitance (EDLC) in 3D arranged mesoporous carbon electrodes with a simple cubic morphology and interdigitated electrodes has been done. Continuum theory has been utilized to study the underlying processes involved in EDLC. Interfacial polarization and ion crowding depend on the electrode’s critical thickness. Porosity increases the capacitance due to the increase in the electrode surface area. The diffuse-layer specific capacitance of ordered mesoporous carbon electrodes in a (C2H5)4NBF4/propylene carbonate organic electrolyte is in the range of 3.2–13.3 μF cm–2, varying according to the electrode thickness. The Stern-layer specific capacitance is 167.6 μF cm–2, and total equilibrium EDLC is in the range of 3.1–12.3 μF cm–2. The effect of the electric field at the electrode–electrolyte interface on reducing electrolyte permittivity has also been discussed. The EDLC of carbonized interdigitated electrodes is analyzed in a 6 M KOH electrolyte. The diffuse-layer specific capacitance ranges from 118.7 to 352.0 μF cm–2 depending on the width of the interdigitated electrodes. The Stern-layer specific capacitance is 91.2 μF cm–2, and the total EDLC value is 51.6–72.4 μF cm–2. The modeling and simulation approach can be applied to different mesoporous electrodes by varying the supercapacitor component’s parameters and geometry.

RETRACTED: Capacitive Behavior of Aqueous Electrical Double Layer Based on Dipole Dimer Water Model

“…In Molecular Dynamics and Monte Carlo simulations [ 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ] of the EDLCs, realistic force fields can be used; for example, solvent water is modeled by popular water models such as the SPC/E model. Ions can have very complex structures, such as organic ionic liquids.…”

Effect of simple cubic, face-centered cubic, and body-centered cubic-electrodes on the electric double layer capacitance of supercapacitors

“…The positive interfacial potential is constant at 0.81 V till 36 no. of spheres in SC morphology [22].…”

“…The changes in the orientation of the electrolyte ions due to the ion crowding effect vary the compactness of the EDL and balance the maximum interfacial potential, which reduces to 0.9 V from 72 unit cells [40]. The magnitude of the minimum diffuse-layer potential increases and stabilizes at 0.11 nV from 37 to 72 spheres in SC morphology due to the ion crowding effect [22]. Similarly, as in BCC, the interfacial potential decreases to 0.80 V between 37 to 72 spheres in SC morphology.…”

Molecular Insights into Curvature Effects on the Capacitance of Electrical Double Layers in Tricationic Ionic Liquids with Carbon Nanotube Electrodes

“…The simulation systems consist of CNT electrodes and the TIL [C 6 (mim) 3 ](Tf 2 N) 3 or the MIL [C 6 mim][Tf 2 N] electrolyte. The (6,6), (8,8), (12,12), and (15,15) CNTs, which correspond to radii (R) of 0.41, 0.54, 0.81, and 1.02 nm, respectively, were immersed in the center of the IL boxes. These boxes were set to be 2(R + 4) nm and 7.61 nm along the radius direction and z-direction, respectively (Figure S1) to meet a bulk density far from the electrode.…”

“…Electrochemical capacitors, also named supercapacitors, store energy by adsorbing counterions at the charged electrode surfaces. , By providing the capability of yielding rapid charge and discharge, and enduring cycle lifetimes, supercapacitors supply the gap between batteries with great charge capacity but modest power and conventional capacitors with high power but limited energy density, which have stimulated a great deal of interest in supercapacitors in the field of energy storage. − Carbonaceous materials such as onion-like carbons, activated carbons, multi- and single-walled carbon nanotubes (SWCNTs), and graphene have attracted a great deal of attention as supercapacitor electrodes. − In these materials, CNT-based electrodes are favorable for high-power and high-energy density supercapacitors. , As verified by the result, high-density SWCNT-based electrodes residing parallel to electrolytes in supercapacitors have exceptional capacitive performance and conductivity, which is facilitated by their large surface areas that are available for ionic adsorption and remarkable ion transportation ability.…”