462263 Influence of Molecular Simulation Model Accuracy on the Interfacial Properties of an Ionic Liquid

Wednesday, November 16, 2016: 3:45 PM
Union Square 25 (Hilton San Francisco Union Square)
Justin B. Haskins and John W. Lawson, Thermal Protection Materials Branch, NASA Ames Research Center, Moffett Field, CA

Increasing the energy storage capability of ionic liquid supercapacitors will require better understanding of ion-electrode interactions. We have probed the influence of these interactions on the structure and differential capacitance of an ionic liquid ([EMIM][BF4]) at an ideal graphite interface as a function of model accuracy. Of note, differential capacitance is determined through newly derived and validated fluctuation formulas. In terms of model accuracy, we test electrostatic techniques, electrode charging techniques, and electrolyte interatomic potentials. For electrostatic summations, we employ high cost, high fidelity techniques as well as less expensive, approximate techniques for summation in slab geometry. For electrode charging, uniform, constant-charge and environmentally responsive, constant-potential conditions are employed. For the ionic liquid, constant charge and atomically polarizable models are employed. We comment on the role of model accuracy on the structure and energetics of the electric double layer as well as on the magnitude and shape of differential capacitance.

Extended Abstract: File Not Uploaded
See more of this Session: Interfacial Phenomena in Ionic Liquids
See more of this Group/Topical: Engineering Sciences and Fundamentals