The aim of this project is to develop low-cost, high-safety media for the storage of hydrogen, which also have minimal technologic and maintenance requirements. Target storage media will be ideally suitable for space-based infrastructures on near planets (e.g., Mars) or satellites (e.g., Moon), where hydrogen will be produced from planetary water bodies by solar cell-powered electrolysis.
Currently, hydrogen is stored in pressurized cylinders, or in metal hydrides and similar compounds that require high energy consumption to store and recover H2.
The storage media that the present project will develop are clathrate hydrates of hydrogen, a class of supramolecular solids consisting of water molecules organized in cage structures that can host one or more gas molecules. These systems represent a safer, technologically simpler, and cheaper alternative for large-scale hydrogen storage than traditional storage methods. Clathrate hydrates are formed under conditions of pressures around 5-10 MPa and temperatures of around 250-280 K, or, importantly, under lower pressures and very low temperatures.
Thus, important features that we want to exploit in this research project are the following:
• clathrate hydrates are essentially made up of water, an economical, ecological and safe compound par excellence. Having a potentially infinite life cycle, water is an ideal material for this purpose.
• Water is found on (or just below) planet and satellite surfaces.
• Sun-shaded or deep crater areas of planets and satellites reach temperatures as low as 30 K
• Hydrogen hydrates can form at very low temperatures under mild gas pressures
This project aims to overcome some critical points of hydrogen storage in clathrates, namely (i) slow capture kinetics, and (ii) low gravimetric content. As for point (i), the PI has already developed and patented processes and molecules for improving the kinetics of the process of 1- 2 orders of magnitude. The increase of the gravimetric content (point (ii)) will instead be addressed with the design and test of stabilizers (co-formers) of the hydrate cages, through a combination of rational design, quantum mechanical and molecular dynamics approaches, stochastic methods, and chemical synthesis. The goal will be to develop a hydrogen storage medium with a gravimetric H2 content around 4 wt%, which is demonstrably competitive with current top technologies at a fraction of the technological level and economic cost.