Long-term atomistic simulation of hydrogen diffusion in metals

Whereas great strides have been taken towards the characterization of metal-based nanomaterials for high-speed, high capacity, reversible hydrogen storage applications, most mesoscopic approaches to date have relied on molecular dynamics (MD) as their chief representational and computational paradigm. However, the absorption and desorption of hydrogen in nanomaterials is characterized by an atomic, deformation-diffusion coupled process with a time scale of the order of seconds to hours-far beyond the characteristic time windows of MD-based simulations. In this work, we present an application of a novel deformation-diffusion coupled computational framework, which allows the long-term simulation of such slow processes and at the same time maintains a strictly atomistic description of the material. Specifically, we have studied the diffusion of hydrogen in palladium nanofilms and compared our predictions with previous hydrogen desorption results obtained by electrochemical cycling experiments.