Unexpected dehydrogenation behavior of LiBH4/Mg(BH4)2 mixture associated with the in situ formation of dual-cation borohydride

In this paper, we report an experimental study of the mixed alkali metal and alkaline-earth metal borohydrides. It was found that dual-cation (Li, Mg) borohydride was in situ formed during the mechanical milling and subsequent heating process of 1:1 LiBH4/Mg(BH4)2 mixture. Compared with the constituent phases, the dual-cation borohydride exhibits lower onset dehydrogenation temperature. Furthermore, property examination results showed that the dehydrogenation reaction of the dual-cation borohydride may involve different mechanistic pathway from that of the constituent borohydrides. These findings suggest a viable approach for tailoring the dehydrogenation property of borohydrides, and should be of significance for better understanding the structure and property of ionic borohydrides.