Hydrogen Storage: Essential Material Properties for Efficient and Sustainable Applications

(a) 'Viscosity': Lower viscosity is desirable for hydrogen storage materials as it enables smoother transport of the carrier materials throughout the reactor/storage system, improving overall efficiency.

(b) 'Gas stream purity': Contaminants such as CO or NH3 in the hydrogen gas stream can negatively impact the efficiency of energy production by poisoning catalysts used in fuel cells. Therefore, materials or processes that produce contaminant-free hydrogen gas are highly desirable.

(c) 'Reversibility': To ensure sustainable hydrogen storage, both the discharge of hydrogen from the charged fuel and the regeneration of the charged fuel from spent fuel need to be feasible in a cost-effective and environmentally friendly manner. The thermodynamics of both the dehydrogenation and regeneration processes must be considered.

(d) 'Stability': Thermal and photolytic stability of both the charged fuel and spent fuel is crucial to maintain the continuity of the charging/discharging cycle in hydrogen storage systems.

(e) 'Toxicity': The selected materials for hydrogen storage should have low toxicity to guarantee safe handling and storage practices.