Rehydrogenation and cycle studies of LiBH4–CaH2 composite

Complex and liquid hydrides for energy storage

“…In this case, the dehydrogenation temperature of the composite should be lower than that of the less stable component. LiBH 4 -CaH 2 [212][213][214], LiBH 4 -CeH 2?x [215,216], LiBH 4 -YH 3 [217] and the Mg(NH 2 ) 2 -LiH [218] systems are known examples of these mutually destabilized RHCs. The main thermodynamic driving force to decrease the dehydrogenation temperature of them is the formation of more stable dehydrogenation products such as metal borides (CaB 6 , CeB 6 and YB 4 ) or mixed imide (Li 2 Mg(NH) 2 ).…”

Improved hydrogen storage reversibility of LiBH4 destabilized by Y(BH4)3 and YH3

“…The ball milling of LiBH 4 with a variety of hydrides including MgH 2 [6e9], CaH 2 [10,11], CeH 2 [10,12e14], YH 3 [12,15,16] and LaH 2 [17] is an effective approach to modify the thermodynamic stability of LiBH 4 . The addition of a hydride to LiBH 4 leads to the formation of more stable end products (metal boride), reducing the overall enthalpy change of the dehydrogenation reaction and thus the dehydrogenation temperature.…”

Rare Earth Borohydrides—Crystal Structures and Thermal Properties

“…Indeed, additives such as MgH 2 [62,63], CaH 2 [64,65], CeH 2 /LaH 2 [66] and Al [67,68] have been used successfully to lower the stability of LiBH 4 by the formation of MgB 2 , CaB 6 and AlB 2 , respectively. For a composite containing LiBH 4 -MgH 2 (2:1), a two-step decomposition is observed at high temperatures (>400 • C) [62,63,69] while for LiBH 4 -CaH 2 (6:1) decomposition occurs in a single step reaction, which is advantageous for reversible hydrogen storage applications [64]. In addition to hydrides, halides such as TiCl 3 , TiF 3 and ZnF 2 have been recently employed to reduce the decomposition temperature of LiBH 4 through cation exchange and formation of an unstable transition metal borohydrides [70].…”