Molecular dynamics simulations of hydrogen storage in various subsurface sandstone aquifers

Abstract

The advent of underground hydrogen storage technology provides innovative insights for safe, efficient, and sustainable hydrogen storage on a large scale. The diffusion and adsorption behavior of hydrogen in sandstone slits at different pressure and temperature were investigated using molecular dynamics simulations. The results indicate that: (1) There are two kinds of hydrogen storage states in aqueous environment: free state and adsorption states. (2) Relatively low temperature and moderate pressure could reduce hydrogen loss and promote hydrogen storage. In particular, the diffusion and storage of hydrogen are more sensitive to pressure than temperature. (3) The hydrogen diffusion coefficient decreases with the increasing salt concentrations, particularly for NaCl. (4) Hydrogen tends to adsorb on –CH₃ surface. Our findings will improve the understanding of underground hydrogen storage in salt-bearing sandstone aquifers and would help to further explore the feasibility of large-scale underground hydrogen storage.