A First-Principles Approach to Modeling Interfacial Capacitance in Graphene-Based Electrodes

Abstract

We present a first-principles computational model to calculate the interfacial capacitance of low-dimensional materials in contact with a bulk substrate. The model is based on density functional theory (DFT) calculations and incorporates key electrostatic and quantum mechanical components of electric field shielding in a nanoscopic interface. A material-agnostic formalism based on classical electromagnetic theory is introduced that allows the quantification of the electrostatic interfacial capacitance. The case studies investigated are the interfaces of monolayer graphene and bilayer graphene adsorbed on a silica substrate. Our model predicts the electrostatic capacitance in the studied interfaces to be field-independent, resulting in a reduction of the slope of the quantum capacitance with a shift in its minimum, aligning accurately and consistently with experimental measurements for both monolayer and bilayer graphene. The model provides an improved representation of the interfacial capacitance of low-dimensional materials, offering a better understanding of the electrochemical behavior of nanoscopic interfaces.

Unraveling the Quantum Capacitance of Graphene Slit Pores with Ions under Extreme Confinement: A First-Principles Study

“…While existing microporous models generally capture experimental trends, they tend to overestimate capacitance by an order of magnitude . This discrepancy can be attributed to the absence of quantum capacitive contributions that impacts the overall capacitance of the pore/ion system . In addition, the hard-sphere assumption for the confined ions may overestimate their diameter within extreme confinement conditions, neglecting atomistic irregularities and conformational changes that may occur due to steric hindrance and pore/ion interactions .…”

“…Energy storage at the nanoscale is governed by both electrostatic and quantum mechanical principles. , The quantum capacitance ( C q ) directly relates to the morphological and material properties of the pore and the composition of the confined ion, dictated by their respective electronic structures . The pore’s electronic structure is also sensitive to the presence of defects or impurities. − Additionally, under ionic confinement, the electronic structures can be further perturbed by the ion–pore interactions due to molecular orbital overlap and (partial) charge transfer. , The C q of a given system can be numerically evaluated from its electronic density of states (DOS), which can be approximated at room temperature using C q = e 2 DOS .25em ( e V ) where e is the electron charge and V is the electrode potential.…”

Electronic structures and quantum capacitance of twisted mixed-dimensional van der Waals heterostructures of graphene/C2H based on tight-binding model

“…For instance, the small C q of graphene sets obstacles in graphene serving as electrodes in electronic devices owing to the induced additional voltage drop during the carriers modulation, which limits the development of low-power consumption electronic devices [7]. Moreover, the series relation between C q and the traditional electrical double layer capacitance results in the limited effective electrical double layer capacitance, which severely depresses the energy density of supercapacitors with graphene as electrodes [8,9]. In order to improve the C q of graphene, it is significant to explore effective schemes to improve the DOS around the E F .…”