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Metal hydride material requirements for automotive hydrogen storage systems  [PDF]
Jose Miguel Pasini,Claudio Corgnale,Bart A. van Hassel,Theodore Motyka,Sudarshan Kumar,Kevin L. Simmons
Physics , 2013, DOI: 10.1016/j.ijhydene.2012.08.112
Abstract: The United States Department of Energy (DOE) has published a progression of technical targets to be satisfied by on-board rechargeable hydrogen storage systems in light-duty vehicles. By combining simplified storage system and vehicle models with interpolated data from metal hydride databases, we obtain material-level requirements for metal hydrides that can be assembled into systems that satisfy the DOE targets for 2017. We assume minimal balance-of-plant components for systems with and without a hydrogen combustion loop for supplemental heating. Tank weight and volume are driven by the stringent requirements for refueling time. The resulting requirements suggest that, at least for this specific application, no current on-board rechargeable metal hydride satisfies these requirements.
Synthesis and Characterization of Metal Hydride/Carbon Aerogel Composites for Hydrogen Storage
Kuen-Song Lin,Yao-Jen Mai,Su-Wei Chiu,Jing-How Yang,Sammy L. I. Chan
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/201584
Abstract: Two materials currently of interest for onboard lightweight hydrogen storage applications are sodium aluminum hydride (NaAlH4), a complex metal hydride, and carbon aerogels (CAs), a light porous material connected by several spherical nanoparticles. The objectives of the present work have been to investigate the synthesis, characterization, and hydrogenation behavior of Pd-, Ti- or Fe-doped CAs, NaAlH4, and MgH2 nanocomposites. The diameters of Pd nanoparticles onto CA’s surface and BET surface area of CAs were 3–10 nm and 700–900 m2g−1, respectively. The H2 storage capacity of metal hydrides has been studied using high-pressure TGA microbalance and they were 4.0, 2.7, 2.1, and 1.2 wt% for MgH2-FeTi-CAs, MgH2-FeTi, CAs-Pd, and 8 mol% Ti-doped NaAlH4, respectively, at room temperature. Carbon aerogels with higher surface area and mesoporous structures facilitated hydrogen diffusion and adsorption, which accounted for its extraordinary hydrogen storage phenomenon. The hydrogen adsorption abilities of CAs notably increased after inclusion of metal hydrides by the “hydrogen spillover” mechanisms.
The effect of palladium coating on hydrogen storage alloy electrodes for nickel/metal hydride batteries
Visintin, A.;Tori, C.A.;Garaventta, G.;Triaca, W.E.;
Journal of the Brazilian Chemical Society , 1997, DOI: 10.1590/S0103-50531997000200007
Abstract: charge / discharge studies carried out on pd - coated misch metal - based alloys for use in nickel-metal hydride batteries are presented. the effect of pd coating on the voltammetric characteristics, life cycle behavior, and rate capability of the alloy electrodes was determined. the number of cycles required to activate the alloy electrodes decreases with an increase in the pd content. the results also show that pd - coated alloys exhibit higher storage capacities and better performance than bare alloys.this improved performance can be attributed to the catalytic effect of pd on the hydrogen electrode reaction.

JIANG Jianjun,

金属学报 , 1997,
Abstract: To determinate an appropriate method measuring the performance of a metal hydride electrode, three different electrochemical apparatus were designed. The results showed that electrochemical capacity of hydride measured by a conventional three-electrode open cell was higher than that determined in a sandwiched and in a sealed Ni/MH test cell.The electrochemical capacity of a hydride electrode measured in a sandwiched Ni/MH cell was very close to that measured in a sealed test cell. In order to optimize the metal hydride electrode alloy and elevalute the discharge capacity of an alloy, the factors affecting the discharge process of an actual hydride electrode were examined theoretically and experimentally. It can be concluded that the electrochemical capacity of a hydride electrode depends not only on the intrinsic properties of a hydrogen storage alloy, but also on the electrode preparation method and its working environment.
Hydrogen storage in complex metal hydrides  [PDF]
Journal of the Serbian Chemical Society , 2009,
Abstract: Complex metal hydrides such as sodium aluminohydride (NaAlH4) and sodium borohydride (NaBH4) are solid-state hydrogen-storage materials with high hydrogen capacities. They can be used in combination with fuel cells as a hydrogen source thus enabling longer operation times compared with classical metal hydrides. The most important point for a wide application of these materials is the reversibility under moderate technical conditions. At present, only NaAlH4 has favourable thermodynamic properties and can be employed as a thermally reversible means of hydrogen storage. By contrast, NaBH4 is a typical non- -reversible complex metal hydride; it reacts with water to produce hydrogen.
Experimental Investigations of Hydrogen Purification by Purging through Metal Hydride  [cached]
Blinov D.V.,Malyshenko S.P.,Borzenko V.I.,Dunikov D.O.
Proceedings of the International Conference Nanomaterials : Applications and Properties , 2012,
Abstract: In an experimental stand [1] for investigation of properties of hydrogen accumulating the materials investigated a new type of reactor cleaning and storage of hydrogen. The applicability of hydrogen purging through metal hydride beds for the purification from non-poisoning admixtures is studied experimentally. The main characteristics of the process together with the main technical barriers of the proposed technology are defined. Specially designed stainless steel continuous flow reactor filled with LaFe0.1Mn0.3Ni4.8 intermetallic compound is tested at variable inlet hydrogen/inert gas composition with measuring mass flow, pressure, temperature and hydrogen content at the outlet both for charging and discharging mode. The estimations of hydrogen losses and purification capacity show certain advantages of the studied technology in comparison with PSA-like mode [1], especially from the point of view of operation regime simplification. The evident process slow-down observed in the experiment is connected with saturation of metal hydride porous bed by hydrogen and with temperature increase due to high thermal effect at sorption (~ 40 kJ/mole Н2). The ways for heat and mass transfer optimization together with the range of applicability of the method for fine hydrogen purification are described and discussed.

GUO Jin,LI Chonghe,CHEN Nianyi,

金属学报 , 1996,
Abstract: The partial least square(PLS) method is applied to the formability of hydride and hydrogen storage properties of binary transition metal alloys. The results show that the mathematical model describing the formation of hydrogen storage materials of binary transition metal alloys can be built by using chemical bond parameters and pattern recognition method, which is useful for hydrogen storage materials design.
Metastable Metal Hydrides for Hydrogen Storage  [PDF]
Jason Graetz
ISRN Materials Science , 2012, DOI: 10.5402/2012/863025
Abstract: The possibility of using hydrogen as a reliable energy carrier for both stationary and mobile applications has gained renewed interest in recent years due to improvements in high temperature fuel cells and a reduction in hydrogen production costs. However, a number of challenges remain and new media are needed that are capable of safely storing hydrogen with high gravimetric and volumetric densities. Metal hydrides and complex metal hydrides offer some hope of overcoming these challenges; however, many of the high capacity “reversible” hydrides exhibit a large endothermic decomposition enthalpy making it difficult to release the hydrogen at low temperatures. On the other hand, the metastable hydrides are characterized by a low reaction enthalpy and a decomposition reaction that is thermodynamically favorable under ambient conditions. The rapid, low temperature hydrogen evolution rates that can be achieved with these materials offer much promise for mobile PEM fuel cell applications. However, a critical challenge exists to develop new methods to regenerate these hydrides directly from the reactants and hydrogen gas. This spotlight paper presents an overview of some of the metastable metal hydrides for hydrogen storage and a few new approaches being investigated to address the key challenges associated with these materials. 1. Introduction The doubling of the world’s energy consumption over the next fifty years [1] will require significant changes in the way we produce, distribute, store, and use energy. A crucial step in this process will be reducing our dependence on carbon-based fossil fuels. The rapidly growing global demand for oil will likely outpace production within a few decades (if it has not already). Although petroleum fuels can be produced from coal through a Fischer-Tropsch process, this method is costly and will likely result in greater greenhouse gas (e.g., CO2) emissions. Hydrogen is a versatile, clean energy carrier that can be produced from natural gas reforming and a variety of carbon free energy sources such as solar, wind, and nuclear energy through water electrolysis. Hydrogen can easily be converted into mechanical or electrical energy through a combustion reaction or fuel cell, respectively. In both cases the hydrogen reacts with oxygen to produce water and energy ( with a theoretical energy of theoretical energy density of 120?kJ/g). Hydrogen storage remains one of the more challenging technological barriers to the advancement of hydrogen fuel cell technologies for mobile applications. Since hydrogen is a gas at standard pressure
A Review of Recent Advances on the Effects of Microstructural Refinement and Nano-Catalytic Additives on the Hydrogen Storage Properties of Metal and Complex Hydrides  [PDF]
Robert A. Varin,Leszek Zbroniec,Marek Polanski,Jerzy Bystrzycki
Energies , 2011, DOI: 10.3390/en4010001
Abstract: The recent advances on the effects of microstructural refinement and various nano-catalytic additives on the hydrogen storage properties of metal and complex hydrides obtained in the last few years in the allied laboratories at the University of Waterloo (Canada) and Military University of Technology (Warsaw, Poland) are critically reviewed in this paper. The research results indicate that microstructural refinement (particle and grain size) induced by ball milling influences quite modestly the hydrogen storage properties of simple metal and complex metal hydrides. On the other hand, the addition of nanometric elemental metals acting as potent catalysts and/or metal halide catalytic precursors brings about profound improvements in the hydrogen absorption/desorption kinetics for simple metal and complex metal hydrides alike. In general, catalytic precursors react with the hydride matrix forming a metal salt and free nanometric or amorphous elemental metals/intermetallics which, in turn, act catalytically. However, these catalysts change only kinetic properties i.e. the hydrogen absorption/desorption rate but they do not change thermodynamics (e.g., enthalpy change of hydrogen sorption reactions). It is shown that a complex metal hydride, LiAlH 4, after high energy ball milling with a nanometric Ni metal catalyst and/or MnCl 2 catalytic precursor, is able to desorb relatively large quantities of hydrogen at RT, 40 and 80 °C. This kind of behavior is very encouraging for the future development of solid state hydrogen systems.
MMorinaga,H Yukawa,

金属学报(英文版) , 2000,
Abstract: The electronic structures are calculated by the DV-Xa molecular orbital method employing small model clusters in order to clarify the roles of the hydride forming elements, A, (e.g., La, Zr Ti, Mg) and non-forming elements, B, (e.g., Ni, Mn, Fe) in hydrogen storage alloys. It is confirmed from this calculation that hydrogen interacts more strongly with hydride non-forming elements, B, than hydride forming elements, A, in agreement with our previous calculations. However,the B-H interaction is enhanced only when some A element exists in the neighborhood. Otherwise, such a B-H interaction never operates in the alloy. In this sense,the coexistence of A and B elements are essential in the constitution of hydrogen storage alloys. Also, it is shown that the A/B compositional ratio of hydrogen storage alloys is understood in terms of a simple parameter, 2Bo(A - B) / /Bo(A - A) Bo(B-B)], where the Bo(A-B), Bo(A-A) and the Bo(B-B) are the bond strengths between atoms given in the parentheses.
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