Mechanically alloyed magnesium-based materials For hydrogen storage

Mechanical alloying is very promising technique for fabrication of hydrogen storage materials possessing good hydriding properties. Magnesium and magnesium-based alloys are attractive from hydrogen capacity point of view, but the kinetics of hydridingdehydriding of magnesium are not sufficiently fast even at elevated temperature. Moreover, the theoretical hydrogen capacity is never achieved in practice. In this work, various approaches to improving hydrogen storage properties of magnesium-based materials with the help of mechanical alloying are discussed and some experimental results illustrate the possibility of each approach. It is demonstrated that improving the hydrogen storage properties of known hydrogen absorbing materials is possible by affecting their structure, morphology, surface properties and so on, using mechanical activation and mechanical alloying with various types of additives. It is possible to search for new hydrogen absorbing materials by means of mechanochemical fabrication of metastable composites of components very different in nature including thermodynamically immiscible ones. These composites may possess very interesting hydrogen storage properties and serve as precursors for the synthesis of new phases. Direct synthesis of metastable intermetallic compounds or hydrided phases in the course of mechanical alloying also opens opportunities to obtain materials promising for hydrogen storage

Metal hydrides for concentrating solar thermal power energy storage

The development of alternative methods for thermal energy storage is important for improving the efficiency and decreasing the cost for Concentrating Solar-thermal Power (CSP). We focus on the underlying technology that allows metal hydrides to function as Thermal Energy Storage (TES) systems and highlight the current state-of-the-art materials that can operate at temperatures as low as room-temperature and as high as 1100 oC. The potential of metal hydrides for thermal storage is explored while current knowledge gaps about hydride properties, such as hydride thermodynamics, intrinsic kinetics and cyclic stability, are identified. The engineering challenges associated with utilising metal hydrides for high-temperature thermal energy storage are also addressed

Cooperative effects at decomposition of powder magnesium hydride

The detailled kinetic analysis of decomposition of powder magnesium hydride revealed tat the particles of magnesium hydride react not independently from each other..

Mechanochemically prepared magnesium-based materials for hydrogen storage

Various mechanochemical approaches to improvement of hydrogen storage properties of Mg-based materials are discussed and some experimental results illustrate the possibility of each approach. It is demonstrated that mechanochemical methods are effective both for improving hydriding characteristics of known hydrogen absorbing phases and for search for new materials for hydrogen storage

Mechanochemically prepared magnesium-based materials for hydrogen storage

Various mechanochemical approaches to improvement of hydrogen storage properties of Mg-based materials are discussed and some experimental results illustrate the possibility of each approach. It is demonstrated that mechanochemical methods are effective both for improving hydriding characteristics of known hydrogen absorbing phases and for search for new materials for hydrogen storage

Cooperative effects at formation and decomposition of magnesium hydride in powders

The detailed kinetic analysis of formation and decomposition of powder magnesium hydride has shown that in contrast to conventional coarse-grained magnesium in which particles seem to react independently from each other, contacts between particles are important at hydriding of nanostructural magnesium because it facilitates the nucleation process hampered in nano-sized particles. The cooperative effects have been revealed also at decomposition of powder magnesium hydride. Being limited by recombination and desorption of hydrogen, the reaction of decomposition of magnesium hydride starts on the particles containing metal impurities or being in contact with the metal surface of container. The nuclei of metallic magnesium formed in these particles initiate the nucleation in the neighboring particles being in contact with them. Nucleation propagates like a chain process. Separation of particles by dilution of the sample by inert additive leads to considerable decrease of the reaction rate

Cooperative effects at decomposition of powder magnesium hydride

The detailled kinetic analysis of decomposition of powder magnesium hydride revealed tat the particles of magnesium hydride react not independently from each other..