Bøger af Ryota Gemma

Ever since the energy crisis in 1970¿s, hydrogen (H) has been regardedas one of the carbon-free secondary energy sources. In this context, hydrogenstorage materials have been considered as possible candidates ofclean energy storage media (see e.g. website of Department of Energy inUS [DOE]). Hydrogen is the smallest and the lightest element and thuscan be easily absorbed in interstitial sites of metal lattice. A pioneeringwork in this field is known by Sieverts [Siev29]. In some of metal alloyswith tailored composition, considerable amount of hydrogen (several wt%)can be reversibly stored through metal/metal hydride (MH) phase transition,just by controlling pressure or temperature [Vught70]. Practically,some of them (LaNi5, TiFe) are really easy to handle and have alreadybeen utilized for technical applications like in fuel cell system [Iwas03] orin MH refrigerator [Uchi04] after intensive studies and developments inthis field. Owing to its extraordinary high volume density and high stability,such metal hydrides still hold advantage to other storage methodslike liquid hydrogen or high-pressure H2 gas tanks. Currently, further researchand development is on the way focusing on improvement of gravimetrichydrogen density and reaction kinetics [Orimo07, Dornh07].