LiBH$_{4}$+Ca(BH$_{4})_{2}$ composite system for hydrogen storage

LiBH$_{4}$ is one of the promising candidates for hydrogen storage materials because of its high gravimetric and volumetric hydrogen capacity. However, dehydrogenation of LiBH$_{4}$ occurs above 400$^{\circ}$C, which limits its use in its pristine form. By mixing with Ca(BH$_{4})_{2}$, we have tried to lower the dehydrogenation temperature. The underlying design principle of this composite system is the recently proven reversibility of 6LiBH$_{4}$+CaH$_{2}$ composite and Ca(BH$_{4})_{2}$ itself. Using differential scanning calorimetry and in-situ synchrotron XRD measurement, we observed eutectic melting of (1-$x)$LiBH$_{4}+x$Ca(BH$_{4})_{2}$ at around 200$^{\circ}$C in a wide range of $x$. The decomposition characteristics and the hydrogen capacity of this composite vary with $x$, and at a certain value of $x$ we found that decomposition was finished below 400$^{\circ}$C showing more than 10 wt{\%} hydrogen capacity. Reversibility of this system was also confirmed.