Research projects

Molecular dynamics simulations of supercapacitors

Supercapacitors are of great interest as energy storage systems because they exhibit very high rates of charge/discharge, long cycle lifes, and they are made of cheap and light materials. These attractive properties arise from the electrostatic nature of the charge storage which results from ion adsorption in the electrode pores. In 2006, it was demonstrated that ions can enter pores of sub-nanometer sizes leading to a huge increase of capacitance. This was an important breakthrough as the energy density of supercapacitors, relatively low compared to batteries, is what currently limits their application. The progress towards better supercapacitors is limited by our incomplete understanding of the relation between their performance, in particular their capacitance and charging rate, and the complex structure of the porous carbon electrodes.

To make progress we need a better fundamental understanding of the ion transport and electrolyte structure in the pores. In this research project, we carry out molecular dynamics simulations of supercapacitors in order to establish key trends for the relationship between geometrical descriptors and electrochemical performances. We use molecular simulations to calculate a number of properties relevant to the determination of the electrochemical performances (capacitance, diffusion coefficients, electrical conductivities,...) and extract the relevant microscopic information in order to propose relationships between structure and performance.

New Monte Carlo / lattice simulations for the prediction of macroscopic properties

This research project focuses on the development of new lattice methods to bridge the gap between molecular simulations and macroscopic properties typically measured experimentally. This has been shown to work for NMR spectra prediction in both porous carbons and battery materials and will now be applied to other macroscopic properties such as diffusion coefficients, capacitances, cyclic voltammetry curves, etc... The mesoscopic models developed in this work are very useful to study materials with different local orderings, e.g. different phases or different degrees of charge ordering in the case of battery materials.