Ammonia-borane (NH3BH3), a potential candidate for effective chemical hydrogen storage, garnered much interest due to its high hydrogen storage capacity of 19.6 wt% and low molecular weight, which are ideal features for hydrogen storage material. Even though ammonia-borane has a high molecular hydrogen storage capacity, only 2/3 of this hydrogen is readily accessible. The modification of ammonia-borane is desirable to improve many of the properties of this promising hydrogen storage material. We have undertaken a systematic study of ammonia-borane derivatives that can quickly release hydrogen and be reprocessed using hydrogen pressure. The materials we have prepared are derivatives of ammonia-borane where a new covalent bond between the nitrogen and a metal or a main group element, has been formed (eg: M(NH2BH3)n, where; M = Ca, Mg, Ti, Sc etc. n = 1-6). They have significantly different thermal properties than ammonia-borane, undergo loss of H2 without significant foaming, a common problem associated with solid NH3BH3 and offer several advantages over NH3BH3 including better thermal stability and more controlled hydrogen release over a wider temperature range.
