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

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.