The Challenge of Storage in the Hydrogen Energy Cycle: Nanostructured Hydrides as a Potential Solution

Hydrogen has the capacity to provide society with the means to carry ‘green’ energy between the point of generation and the point of use. A sustainable energy society in which a hydrogen economy predominates will require renewable generation provided, for example, by artificial photosynthesis and clean, efficient energy conversion effected, for example, by hydrogen fuel cells. Vital in the hydrogen cycle is the ability to store hydrogen safely and effectively. Solid-state storage in hydrides enables this but no material yet satisfies all the demands associated with storage density and hydrogen release and uptake; particularly for mobile power. Nanochemical design methods present potential routes to overcome the thermodynamic and kinetic hurdles associated with solid state storage in hydrides. In this review we discuss strategies of nanosizing, nanoconfinement, morphological/dimensional control, and application of nanoadditives on the hydrogen storage performance of metal hydrides. We present recent examples of how such approaches can begin to address the challenges and an evaluation of prospects for further development.