Molecular dynamics simulation on hydrate-based hydrogen storage: A review from the perspective of hydrate nucleation and growth

Hydrogen holds a prominent place in the future energy structure due to its high energy density, environmental friendliness, and wide range of production pathways. However, the optimal hydrogen storage and transportation method have not been discovered. Hydrate-based hydrogen storage technology has gained substantial attention owing to its advantages of safety, nonpollution, and easy release. Molecular dynamics (MD) simulation is a vital approach for exploring its underlying mechanisms. Based on MD simulation techniques, we can monitor the process of hydrate nucleation and growth at the molecular level. Here, we systematically reviewed the existing studies on hydrogen hydrate formation from a microscopic perspective. We initially explore the microstructure, basic properties, and phase equilibrium characteristics of hydrogen hydrates. Subsequently, we summarize the research progress in pure hydrogen systems and hydrogen-additive binary systems. In addition, we illustrate various key factors affecting the formation of hydrogen hydrates, including cage occupancy ratio, guest concentration, and diffusion. Based on these findings, the development of hydrogen storage technology in the MD simulation area has been further summarized. Furthermore, the hydrogen storage density, hydrogen storage rate and nano confinement effect under different systems have been presented. According to the recent study, the restrictions and future directions of MD simulation on hydrogen hydrates are discussed. This review provides theoretical guidance and insights for the future development of hydrate-based hydrogen storage technology.