Simulated thermal decomposition and detonation of nitrogen cubane by molecular dynamics

Microscopic Simulations of Electrochemical Double-Layer Capacitors

Electrochemical double-layer capacitors (EDLCs) are devices allowing the storage or production of electricity. They function through the adsorption of ions from an electrolyte on high-surface-area electrodes and are characterized by short charging/discharging times and long cycle-life compared to batteries. Microscopic simulations are now widely used to characterize the structural, dynamical, and adsorption properties of these devices, complementing electrochemical experiments and in situ spectroscopic analyses. In this review, we discuss the main families of simulation methods that have been developed and their application to the main family of EDLCs, which include nanoporous carbon electrodes. We focus on the adsorption of organic ions for electricity storage applications as well as aqueous systems in the context of blue energy harvesting and desalination. We finally provide perspectives for further improvement of the predictive power of simulations, in particular for future devices with complex electrode compositions.

Measuring the surface diffusivity of argon in nanoporous carbon

Gas diffusion in porous media consists of surface hopping and non-surface ballistic/bulk diffusion. Unfortunately, only the overall diffusivity is usually measured, without being separated into various diffusion modes. Here, we report a numerical method to differentiate contributions from surface diffusion and non-surface diffusion for argon diffusion in nanoporous carbon using molecular dynamics simulations. The key is to truncate the argon trajectories based on the adsorption/desorption state, and thus attribute mass fluxes according to specific mechanisms during diffusion. Both the surface diffusivity and non-surface diffusivity increase and then decrease as a function of gas loading. Yet, surface diffusivity and non-surface diffusivity behave very differently as a function of the temperature and gas-substrate affinity of the nanoporous network.