Solvation and Stabilization of Superior Alanate Nanostructures

Abstract

NaAlH4 and LiAlH4 are promising materials for hydrogen storage due to their high hydrogen density (7.4 and 10.5 mass%, respectively). However, their practical application is hampered from the slow hydrogen kinetics and poor reversibility. To improve the hydrogen properties of alanates, the alternative core–shell strategy has been proposed. In this respect, a simple solvent evaporation method is presented to synthesize the alanate core. In this approach, NaAlH4 and LiAlH4 are stabilized by solvation and electrostatic forces, respectively, through the addition of ionic salts. Remarkably, it is found that the size of the alanate nanoparticles can be tuned by varying the concentration of the introduced ion. More importantly, the partial substitution of Na+ and Li+ with cations of higher electronegativity enables the release of hydrogen at much lower temperatures.