A mechanical-force-driven physical vapour deposition approach to fabricating complex hydride nanostructures

Abstract

Nanoscale hydrides desorb and absorb hydrogen at faster rates and lower temperatures than bulk hydrides because of their high surface areas, abundant grain boundaries and short diffusion distances. No current methods exist for the direct fabrication of nanoscale complex hydrides (for example, alanates, borohydrides) with unique morphologies because of their extremely high reducibility, relatively low thermodynamic stability and complicated elemental composition. Here, we demonstrate a mechanical-force-driven physical vapour deposition procedure for preparing nanoscale complex hydrides without scaffolds or supports. Magnesium alanate nanorods measuring 20-40 nm in diameter and lithium borohydride nanobelts measuring 10-40 nm in width are successfully synthesised on the basis of the one-dimensional structure of the corresponding organic coordination polymers. The dehydrogenation kinetics of the magnesium alanate nanorods are improved, and the nanorod morphology persists through the dehydrogenation-hydrogenation process. Our findings may facilitate the fabrication of such hydrides with improved hydrogen storage properties for practical applications.

Catalysis and Downsizing in Mg-Based Hydrogen Storage Materials

“…Therefore, good kinetics is essential for hydrogen storage. It is reported that reducing the size of hydrogen storage materials could lead to a remarkable change in hydrogen absorption/desorption kinetics [12,[38][39][40][41]. It is well proven that small particles of hydrides have an influence on hydrogen absorption/desorption kinetic properties, mainly due to shortened hydrogen diffusion and dissociation pathways, and enlarged surface free energy when the size decreases to below a few nanometers [42,43].…”

Enhancing the Regeneration Process of Consumed NaBH4 for Hydrogen Storage

“…[1][2][3][4] However, both hydrogen production and storage are great challenges for realizing the so-called "hydrogen economy." [12][13][14][15][16][17][18] Unfortunately, no methods have been able to achieve the United States Department of Energy (DOE) standards for hydrogen storage so far. Furthermore, hydrogen storage is considered as a bottleneck for the dawn of hydrogen economy and it also attracts an extraordinary amount of research interest.…”

Direct mechanochemical formation of alkali metal borohydrides nanocrystals exhibiting kinetic and thermodynamic destabilizations

“…The reasons for the obtained destabilizations above can be understood from two aspects: (i) the NaBH 4 at a nanoscale level reduce the interdiffusion length of the constituents. This may accelerate mass transfer of the solid phases that is the common ratelimiting step for the dehydrogenation [32]; (ii) the nanosized NaBH 4 is thermodynamically less stable because of higher specific surface areas, abundant grain boundaries than the bulk one [26,33].…”