Many of the biggest challenges in the hydrogen storage research are associated with the fact that the operating mechanisms often involve the complicated coupling of chemical/physical processes over vast ranges of multiple length and time scales. These kinetic phenomena tend to occur at or near several types of solid/solid and solid/gas interfaces, which in turn play key roles in determining the overall performance of hydrogen storage processes. Examples include surface reactions with hydrogen gas; surface, bulk, and interface mass transport processes; structural modifications occurring under operation; and intermediate phase nucleation-and-growth processes associated with hydrogen incorporation. Essentially, these are collective dynamic processes of atomic/molecular species that determine the thermodynamics and kinetics of nano- or micro-level characteristics. However, the lack of clear understanding of associated mechanisms and their impacts on hydrogen generation and solid-state storage reactions has hampered the acceleration of materials discovery and development. Therefore, it is obvious that several modeling approaches that cover different length and time scales ought to be properly integrated in order to comprehensively explore the underlying mesoscale science during the co-evolution of relevant processes. Mesoscale continuum modeling frameworks can provide a unified platform for integrating the necessary atomistic approaches, which typically provide higher accuracy for nanoscale chemical processes, and continuum approaches, which offer far greater flexibility and scalability and can describe materials at the microstructural level. In this talk, we present our integrated effort as part of the DOE Hydrogen Storage Materials—Advanced Research Consortium (HyMARC) under the Energy Materials Network (EMN) towards the multiscale modeling of metal hydrides for solid-state hydrogen storage. In particular, we will discuss our recent efforts on the development of an integrated mesoscale modeling framework that can directly incorporate parameters derived from predictive atomistic modeling approaches such as ab initio calculations and molecular dynamics simulations. Several case studies will be presented, such as modeling phase transformations of simple or complex metal hydrides during the (re/de)hydrogenation.

Mesoscale modeling of metal hydrides for hydrogen storage

255th National Meeting (2018)

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