Non-hydride systems of the main group elements as hydrogen storage materials

This review surveys the state of the art in non-hydride hydrogen storage materials composed of the elements B, C, N, O, Si, and Al. In the nitrogen-based systems Li3N and NH3BH3 hydrogen is chemically bound in the formal oxidation states +1 and −1, whereas carbon nanotubes and aluminosilicate-based zeolites adsorb or encapsulate molecular H2. The advantages and drawbacks of each system are discussed, and comparisons between them are made where appropriate.