Search results for "hydrogen storage"
showing 10 items of 56 documents
Improvement of the desorption kinetics and thermodynamics from CaH2+AlB2 system by NbF5 doping
2014
Effect of nano-structuring on hydrogen sorption properties of materials
2008
Storage of large quantities of hydrogen at safe pressures is a key factor in establishing a hydrogen-based economy [1]. Of the three ways of storing hydrogen, viz. by compressed gas, in liquid form, or as hydride, the latter is rather promising both for its relevant storage capacity and safety [2]. There are several materials which show reversible hydrogen absorption desorption properties. However, to be suitable for the on-board hydrogen storage for vehicular applications, the storage material should have the following properties: (a) high storage capacity; (b) moderate absorption/desorption temperatures; (c) fast hydrogenation/dehydrogenation kinetics; (d) high resistance to degradation a…
Preliminary Tests On A Miniaturized Hybrid Pv-Pemfc System
2007
A regenerative hybrid PV-PEMFC low power system is a suitable solution to replace batteries and to supply small electric devices placed in remote areas with no grid connection. Such a system was designed and built including a PV array, electrolyzer, PEMFC stack (6We) and hydrogen storage tank. As well known a hybrid PV-PEMFC energy system may represent a reliable solution to the renewable energy storage problem. Hydrogen produced by such a system is a clean fuel, suitable to replace traditional fuels which contain carbon damaging the environment. The paper reports results of a preliminary, non-dynamic experimental analysis performed on the system in order to study the effects of the anode p…
INVESTIGATIONS OF THE INFLUENCE OF DIFFERENT ADDITIVES TO THE LANTHANUM RICH MISCHMETAL
2007
Hydrogen Sorption Properties of Metal Hydride and Glass Phase
2009
This work is devoted to the development of a new composite material for hydrogen storage and to investigation of physical and chemical characteristics of material. The new composite material is formed by combination of AB5 type lanthanum nickel alloy with a glass based on silica. Thermogravimetric and XRD measurements prove that the new material absorbs more hydrogen than both constituents separately. That is explained by hydrogen sorption in the composite material due to the hydrogen spillover phenomena, where the hydrogen molecules dissociated on the surface of catalyst in atoms and spills over to the inert surface. That causes the increase of catalytic activity of an alloy and the presen…
ChemInform Abstract: Electrochemical Behavior of Metal Hydrides
2010
Metal hydride electrodes are of particular interest owing to their potential and practical application in batteries. A large number of hydrogen storage materials has been characterized so far. This paper deals with the effect of the chemical nature and stoichiometry of specific alloy families (AB5, A2B, AB/AB2 and AB2) on the hydride stability, hydrogen storage capacity and kinetics of hydrogen sorption-desorption in the solid phase/gas and solid phase/electrolyte solution systems. Special attention has been paid towards the electrochemical properties of metal hydrides in terms of their performance in Ni-MH rechargeable alkaline cells.
Optimal hydrogen storage in sodium substituted lithium fullerides
2017
Through the substitution of Li with Na in Li6C60, we synthesized a series of mixed alkali cluster intercalated fullerides, NaxLi6−xC60. These compounds share lattices of Na6C60 and Li6C60 with a cubic parameter linearly dependent on x. H2 absorption and desorption were studied by means of charge/discharge kinetic measurements and coupled calorimetric–manometric evaluation. By varying the stoichiometry, we found the best compromise among the absorption rate, temperature and amount of hydrogen for x = 0.5 and 1. Small concentrations of Na substituted to Li significantly lower the absorption temperature of Li6C60, improving the hydrogenation capacity, the kinetics, and the dehydrogenation enth…
From determination of the fugacity coefficients to estimation of hydrogen storage capacity: A convenient theoretical method
2015
Abstract The equation of state (EOS) from virial expansion (VE) is used in this work to pave the way for determining the fugacity coefficients of the hydrogen fluid at arbitrary temperature and pressure. The fugacity coefficients from our VE method have more physical meanings than the empirical values. In this way, the hydrogen storage capacity of a novel material model can be estimated by using few density functional theory (DFT) calculations with the aid of a continuum model. The efficient continuum model can provide a more accurate estimation of the hydrogen storage capacity than the pure DFT calculations. Furthermore, the expensive grand canonical ensemble (μNT) simulations combining wi…
Experimental investigation on lithium borohydride hydrolysis
2010
Abstract Lithium borohydride, one of the highest energy density chemical energy carriers, is considered as an attractive potential hydrogen storage material due to its high gravimetric hydrogen density (19.6%). Belonging to borohydride compounds, it presents a real issue to overcome aims fixed by the U.S. Department of Energy in the field of energy, and so crystallizes currently attention and effort to use this material for large scale civil and military applications. However, due to its important hygroscopicity, lithium borohydride is a hazardous material which requires specific handling conditions for industrial aspects. In order to understand much more the reaction mechanism involved bet…
Density functional theory based screening of ternary alkali-transition metal borohydrides: a computational material design project.
2009
We present a computational screening study of ternary metal borohydrides for reversible hydrogen storage based on density functional theory. We investigate the stability and decomposition of alloys containing 1 alkali metal atom, Li, Na, or K M1; and 1 alkali, alkaline earth or 3d / 4d transition metal atom M2 plus two to five BH4 groups, i.e., M1M2BH42‐5, using a number of model structures with trigonal, tetrahedral, octahedral, and free coordination of the metal borohydride complexes. Of the over 700 investigated structures, about 20 were predicted to form potentially stable alloys with promising decomposition energies. The M1Al/ Mn/ FeBH44, Li/ NaZnBH43, and Na/ KNi/ CoBH43 alloys are …