Additives in protic–hydridic hydrogen storage compounds: a molecular study†
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 (ΔEavg = 3.47 eV), LiNH2BH3·BH3 (ΔEavg = 3.75 eV), LiBH2NH3·BH3 (ΔEavg = 3.95 eV] but also compounds like LiNH2BH3:NH3BH3 (ΔEavg = 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.