The impact of carbon materials on the hydrogen storage properties of light metal hydrides

Abstract

The safe and efficient storage of hydrogen is still one of the remaining challenges towards fuel cell powered cars. Metal hydrides are a promising class of materials as they allow the storage of large amounts of hydrogen in a small volume at room temperature and low pressures. However, usually the kinetics of hydrogen release and uptake and the thermodynamic properties do not satisfy the requirements for practical applications. Therefore current research focuses on catalysis and the thermodynamic tailoring of metal hydride systems. Surprisingly, carbon materials used as additive or support are very effective to improve the hydrogen storage properties of metal hydrides allowing fast kinetics and even a change in the thermodynamic properties. Even though the underlying mechanisms are not always well understood, the beneficial effect is probably related to the peculiar structure of the carbon materials. This feature article gives an introduction to the different carbon materials, an overview of the preparation strategies to synthesize carbon/hydride nanocomposites, and highlights the beneficial effect of carbon by discussing two important hydrides: MgH 2 and NaAlH 4 .

Probing the Room Temperature Deuterium Absorption Kinetics in Nanoscale Magnesium Based Hydrogen Storage Multilayers Using Neutron Reflectometry, X-ray Diffraction, and Atomic Force Microscopy

“…5 Until now, the majority of efforts has been directed toward improving the catalytic activity and reducing diffusion limitations. The latter can be achieved by, for instance, confining Mg(H 2 ) inside a porous matrix 6 or by ball milling of Mg(H 2 ) with carbon allotropes 7 to keep the particle size small and diffusion distances short. Ball milling has the added advantage of introducing defects 8 and enabling mixing of transition metal (TM) catalysts to promote hydrogen dissociation on the surface.…”

Solid State NMR Characterization of Complex Metal Hydrides systems for Hydrogen Storage Applications

“…In particular, NMR analysis has been exceptionally crucial for materials that lose their long range order after thermal treatments, which include most borohydrides. Approaches based on nano-engineering have gained growing attention [3,4] since majority of solid state chemical reactions show poor kinetics due to slow mass transport limitations. Numerous studies by NMR appeared [5,6] along this line in the recent literature.…”

The role of Ni in increasing the reversibility of the hydrogen release from nanoconfined LiBH4

“…Nanosizing/nanoconfinement in porous materials such as carbon, [5][6][7][8][9][10] and the use of catalysts, [11][12][13][14][15][16][17] are among the strategies being explored to improve the dehydrogenation and rehydrogenation behaviour. These approaches have been shown to be effective for several hydrides such as NH 3 BH 3 18 and NaAlH 4 .…”