A Comprehensive review of underground hydrogen storage technology via hydrogen Hydrates: Analysis of nucleation Kinetics, phase characteristics and storage mechanisms

To address the issues of high-pressure gaseous hydrogen storage occupying large space and potential safety hazards such as leakage, underground hydrogen storage technology using hydrates has been widely regarded for its ability to provide large-scale, safe, efficient and long-term hydrogen storage solutions. This paper innovatively overcomes the limitations of traditional single-dimensional studies by constructing a cross-scale integration quantitative coupling relationship of “nucleation kinetics − phase characteristics − reservoir optimization.” Firstly, it clarifies the phase characteristics and temperature–pressure conditions of hydrogen hydrates, providing theoretical data for hydrogen storage applications; secondly, it focuses on kinetic mechanisms in bulk and confined spaces, revealing the synergistic effects of “pore size − surface hydrophilicity/hydrophobicity − fluid mobility” on nucleation in confined spaces; finally, it summarizes the mechanisms of hydrate-based hydrogen storage under reservoir conditions (marine reservoirs and permafrost layers). This innovation significantly differs from previous studies: earlier studies often investigated nucleation, phase characteristics, or reservoirs in isolation, and paid insufficient attention to the coupling effects of multiple factors in confined spaces and differentiated reservoir optimization. The main contribution of this research is the establishment of universal theoretical framework and differentiated strategies, providing key technical references and research paradigms for subsequent reservoir optimization and industrial applications.