Exploring the Effect of Pore Morphology On Model Electrochemical Double-Layer Capacitor Systems

Electrochemical double-layer capacitors (EDLCs) have drawn much attention as energy storage devices in recent years due to their long cycle life as well as their ability to uptake and discharge energy very rapidly and to store more energy than typical capacitors. Molecular simulations are employed to study electrochemical properties of model EDLC systems. A variety of simple pore sizes, shapes, and configurations are studied, as well as model carbons, which reproduce structural features of disorder carbons used in EDLC experiments. Surface charge densities of 0 C/m², 5 C/m², 15 C/m², and 25 C/m² are applied to the carbon structure, which are representative of typical values for EDLCs. Solutions of 1M NaCl, NaF, and NaBF₄ are used as electrolytes in each system. We study the effect of surface charge on the electrochemical and structural properties of the electrolyte solution. Of particular interest are: capacitance of the model EDLC system, selectivity of ions to reside in various pore sizes, charge density of the electrolyte solution across the electrode system, and the solvation structure of ions in various confining geometries compared to the bulk solution between electrodes.