In situ hybridization of LiNH2–LiH–Mg(BH4)2 nano-composites: intermediate and optimized hydrogenation properties

Abstract

Nano-composites of LiNH₂–LiH–xMg(BH₄)₂ (0 ≤ x ≤ 2) were prepared by plasma metal reaction followed by a nucleation growth method. Highly reactive LiNH₂–LiH hollow nanoparticles offered a favorable nucleus during a precipitation process of liquid Mg(BH₄)₂·OEt₂. The electron microscopy results suggested that more than 90% of the obtained nano-composites were in the range 200–400 nm. Because of the short diffusion distance and ternary mixture self-catalyzing effect, this material possesses enhanced hydrogen (de)sorption attributes, including facile low-temperature kinetics, impure gases attenuation and partial reversibility. The optimal hydrogen storage properties were found at the composition of LiNH₂–LiH–0.5Mg(BH₄)₂, which was tentatively attributed to a Li₄(NH₂)₂(BH₄)₂ intermediate. 5.3 wt% hydrogen desorption could be recorded at 150 °C, with the first 2.2 wt% release being reversible. This work suggests that controlled in situ hybridization combined with formula optimization can improve hydrogen storage properties.