Molecular Simulation Studies Toward Robust Supercapacitors: Scalable Screening and Modeling of Complex Systems

Abstract

Supercapacitors are electrochemical energy-storage devices that store energy through the physical adsorption of ions at electrode surfaces. As a result, supercapacitors can store and deliver energy at a faster rate but store less energy in comparison to batteries. Supercapacitors are thus relegated to applications such as regenerative braking and memory backups on personal computers, where fast charge/discharge rates are a priority. In order to meet the growing energy demands of the 21st century, supercapacitors must be improved to achieve use in widespread applications.

In order to develop next-generation supercapacitors, the mechanisms of ion transport must be understood at a molecular level. This dissertation explores these mechanisms through the use of molecular simulation. First, trends between electrolyte solvent selection and ion dynamics and structure are investigated through a computational screening of 400+ mixtures of ionic liquids in organic solvents. The connection between local correlations of molecules and the physical properties of water and aqueous electrolytes are then studied through the Van Hove Correlation Function. Next, the topic of tailoring the interlayer spacings of 2-D metal carbides with ion selection for optimal performance is explored. Finally, the development of software for reproducible simulation workflows is briefly discussed.