Abstract

Characterising precisely the structural and dynamical properties of electrolytes at the interface with solids is important for a wide range of applications. Here, we focus on the interface between concentrated electrolytes and carbon surfaces, relevant for energy storage systems such as carbon-carbon supercapacitors, devices which store energy through ion adsorption at the electrode/electrolyte interface. Molecular dynamics simulations is a very useful tool in this context as it allows one to get a microscopic picture of the phenomena at play. Using this type of simulations, we investigated the interface between electrolytes and various carbons: planar and porous, ordered and disordered, with or without surface functional groups. Using coarse-grained models, complex relationships between ion size, pore size, surface functionalisation, degrees of confinement and diffusion coefficients were explored for a range of nanoporous carbons. In some cases, all-atom models are needed to characterise precisely ion orientations and configurations, and ultimately relate molecular simulations results with experiments (e.g. AFM ). In other cases, interpreting experiments requires simulations on much larger length and time scales than what is accessible with molecular simulations. In such instances mesoscopic models can be developed. An example for the simulation of capacitance and NMR spectra will be described.