A mechanism for non-stoichiometry in the lithium amide/lithium imide hydrogen storage reaction.

We demonstrate, through structural refinement from synchrotron X-ray diffraction data, that the mechanism of the transformation between lithium amide and lithium imide during hydrogen cycling in the important Li-N-H hydrogen storage system is a bulk reversible reaction that occurs in a non-stoichiometric manner within the cubic anti-fluorite-like Li-N-H structure.