Additives in protic–hydridic hydrogen storage compounds: a molecular study

Abstract

Here we have studied the dehydrogenation energetics of protic–hydridic based hydrogen storage compounds. Various set of compounds are studied having different ratio of protic and hydridic hydrogens. Moreover, protic–hydridic based chemical additives (NH₃, BH₃ and NH₃BH₃) are added to protic–hydridic based hydrogen storage compounds to increase their hydrogen gravimetric density. Our study shows such chemical additives not only increase their hydrogen gravimetric density but also improve their dehydrogenation properties. Such practice turned out to be excellent as we not only generated some model compounds [LiBH₂NH₃ (ΔE_avg = 3.47 eV), LiNH₂BH₃·BH₃ (ΔE_avg = 3.75 eV), LiBH₂NH₃·BH₃ (ΔE_avg = 3.95 eV] but also compounds like LiNH₂BH₃:NH₃BH₃ (ΔE_avg = 3.85 eV), which has already been reported to be a promising hydrogen storage material. We find the dehydrogenation properties of the reported compounds are best when they have close to equal numbers of protic and hydridic hydrogens.