System, methods and materials for storing and retrieving hydrogen

A system for storing and retrieving elemental hydrogen, said system comprising:

• a housing;
• a hydrogen storage element enclosed within the housing, the hydrogen storage element comprising a solid-state hydrogen storage material, at least a portion of the solid-state hydrogen storage material comprising:
• a porous matrix material comprising atoms of a first element capable of bonding with more than one hydrogen atom per atom of the first element, the atoms of the first element being molecularly arranged within the porous matrix material so that different atoms of the first element have bond sites available for different numbers of hydrogen atoms at correspondingly different levels of bonding energy;
• hydrogen atoms molecularly bonded to atoms of the first element, some atoms of the first element having more hydrogen atoms bonded thereto than other atoms of the first element;
• and
• atoms of a second element capable of molecularly bonding to atoms of the first element and the hydrogen atoms, the atoms of the second element being bonded to those atoms of the first element having bond sites for more than one hydrogen atom and as a consequence at lower bond energies than the bond sites of those atoms of the first element to which a fewer number of hydrogen atoms are bonded;
• and
• a control system for regulating storage of hydrogen into and retrieval of hydrogen from the solid-state hydrogen storage material.