LiAlH₄ as a “Microlighter” on the Fluorographite Surface Triggering the Dehydrogenation of Mg(BH₄)₂: Toward More than 7 wt % Hydrogen Release below 70 °C

Mg(BH4)2 is one of the most promising hydrides for hydrogen storage. Herein, the dehydrogenation properties of Mg(BH4)2 are significantly improved by LiAlH4 and fluorographite (FGi) addition. The metathesis reaction between Mg(BH4)2 and LiAlH4 has been strongly hindered by FGi, and a novel “chocolate cookie” structure is observed that Mg(BH4)2 and LiAlH4 particles scatter uniformly on the FGi surface. An unexpected hydrogen desorption capacity of 7.12 wt % is discovered in the Mg(BH4)2–LiAlH4–30FGi composite at a temperature as low as 68.2 °C. More encouragingly, the rapid dehydrogenation process can be fully accomplished in seconds, indicating an ultrafast hydrogen desorption kinetic behavior. Further investigations find that the remarkably enhanced dehydrogenation behavior is attributed to the interaction between FGi and the two hydrides, which greatly reduces the enthalpy change of the dehydrogenation reaction. This investigation reveals that the LiAlH4 can act as a “microlighter” to trigger the dehydrogenation of Mg(BH4)2 at low temperature.