We propose a set of thermodynamic guidelines aimed at facilitating more robust screening of hydrogen-storage reactions. The utility of the guidelines is illustrated by reassessing the validity of reactions recently proposed in the literature and through vetting a list of more than 20 candidate reactions based on destabilized $\mathrm{Li}\mathrm{B}{\mathrm{H}}_4$ and $\mathrm{Ca}{\left(\mathrm{B}{\mathrm{H}}_4\right)}_2$ borohydrides. Our analysis reveals several reactions having both favorable thermodynamics and relatively high hydrogen densities (ranging from $5\text{to}9\mathrm{wt}\%$ ${\mathrm{H}}_2$ and $85\text{to}100\mathrm{g}$ ${\mathrm{H}}_2∕\mathrm{l}$), and it demonstrates that chemical intuition alone is not sufficient to identify valid reaction pathways.

• Received 13 October 2006

DOI:https://doi.org/10.1103/PhysRevB.76.134102