KOSEN 한인과학기술자네트워크

1. Introduction
2. sII hydrates of hydrogen
3. Semi-clathrates of hydrogen
4. sH hydrates of hydrogen
5. sI hydrates of hydrogen
6. sVI clathrates storing hydrogen
7. Organic and inorganic compounds forming hydrogen hydrates
8. Polymeric materials storing hydrogen clathrates
9. Hybrid storage of hydrogen
10. Multiple hydrogen occupancy
11. Tuning effect observed in hydrogen hydrates
12. Energy analysis for hydrate based hydrogen storage process
13. Future directions
14. Conclusion

Hydrogen is looked upon as the next generation clean energy carrier, search for an efficient material and method for storing hydrogen has been pursued relentlessly. Improving hydrogen storage capacity to meet DOE targets has been challenging and research efforts are continuously put forth to achieve the set targets and to make hydrogen storage a commercially realizable process. This review comprehensively summarizes the state of the art experimental work conducted on the storage of hydrogen as hydrogen clathrates both at the molecular level and macroscopic level. It identifies future directions and challenges for this exciting area of research. Hydrogen storage capacities of different clathrate structures ？ sI, sII, sH, sVI and semi clathrates have been compiled and presented. In addition, promising new approaches for increasing hydrogen storage capacity have been described. Future directions for achieving increased hydrogen storage and process scale up have been outlined. Despite few limitations in storing hydrogen in the form of clathrates, this domain receives prominent attention due to more environmental-friendly method of synthesis, easy recovery of molecular hydrogen with minimum energy requirement, and improved safety of the process.