Selective transport of ions and molecules in
nanoscale energy storage devices
Chemical conversion of solar energy in non-biological systems represents a promising approach to meet the ever increasing global energy demand. The most direct approach involves the catalyzed photodissociation of water to produce oxygen and hydrogen. The latter can be used either directly in combustion processes or in fuel cells generating electricity. In all of these processes, membranes are used to provide physical separation of the various intermediate species or products. Recently, various supra-molecular structures have been proposed where the "molecular sieving" is achieved by carbon nanotubes (CNTs) with high permeability and high selectivity.
The main goal of this project is to understand the sieving mechanism at a molecular level by performing simulations of transport of small molecules through CNTs by means of molecular dynamics simulations. The interaction of molecules with the CNT walls is not only modeled at an empirical level, but the relevant forces are also calculated by quantum chemical methods from first principles, i. e. DFT molecular dynamics simulations. By considering longer and wider CNTs, the transition from molecular dynamics regime to the hydrodynamics regime shall be investigated, eventually resulting in hybrid schemes for the simulation of molecular flow through nanoporous materials.