Showing papers on "Hydrogen storage published in 1993"
TL;DR: In this article, a systematic investigation was conducted detailing the kinetics, extent of hydrogen loading and cycling stability for both the Ni-doped and undoped MgH2-Mg systems as heat and hydrogen storage materials.
124 citations
Abstract: In a previous article we selected a preparation process of cerium and nickel oxides which permits catalysts to be obtained which contain as much hydrogen as the intermetallic compounds with the same composition, and which are more active in benzene hydrogenation. Moreover the catalysts' behaviour varies with the Ni/Ce ratio (x) and at least two zones can be distinguished. In the present paper we have found correlations between catalytic activity, hydrogen content and some physical and chemical characteristics of the solids, both in the oxidized and reduced states. The techniques used were electron microscopy (TEM, SEM, EPMA), X-ray diffraction and X-ray photoelectron spectroscopy. Whatever the method, the catalysts are classified into two families. Forx⩽ 0.5 nickel is inserted in the ceria lattice to form a solid solution. Above 0.5, both crystallized nickel oxide and solid solution coexist. In the reduced state anionic vacancies able to receive hydrogen, probably in an hydridic form, are created in the bulk and at the surface of the solid solution. The catalytic results can then be explained by assuming the existence of three kinds of active sites which differ from each other in terms of the environment of nickel, and an explanation for the higher efficiency of the catalyst withx =5 is advanced. Finally the situation is shown to be almost identical in ceria-supported nickel catalysts.
75 citations
TL;DR: In this paper, a fast solidified LaNi5-based hydrogen storage alloys were prepared by a melt-spinning method, which had very fine crystal grain of below 10 μm.
71 citations
TL;DR: In this article, negative electrodes were made from hydrogen storage alloys (MmNi36Mn04Al03Co07) modified by mixing them with metal oxide powders, and the discharge capacity of cathodes was greatly increased by the modification with metal oxides with high electric conductivity.
57 citations
TL;DR: In this paper, a multicomponent hydrogen storage alloy with composition MMNi3.31Mn0.37A10.28Co 0.64 was used as a negative electrode material.
Abstract: The multicomponent hydrogen storage alloy with composition MMNi3.31Mn0.37A10.28Co0.64 was used as a negative electrode material. After packing the alloy particles in a porous nickel substrate, press forming was carried out to bond them. The effects of particle size and forming pressure on electrode performance were examined in 6 m KOH solution. The electrochemical properties of the negative electrode, such as discharge capacity and high-rate dischargeability, were remarkably improved by increasing the alloy particle size and forming pressure.
50 citations
Patent•
27 Jan 1993TL;DR: A nickel positive electrode for use in alkaline storage batteries which is improved in the rate of utilization of the nickel hydroxide in a wide temperature range with an oxygen evolving overvoltage being increased by incorporating at least one selected from the group consisting of compounds of yttrium, indium, antimony, barium and beryllium into the nickel positive electrodes as discussed by the authors.
Abstract: A nickel positive electrode for use in alkaline storage batteries which is improved in the rate of utilization of the nickel hydroxide in a wide temperature range with an oxygen evolving overvoltage being increased by incorporating at least one selected from the group consisting of compounds of yttrium, indium, antimony, barium and beryllium, and at least one selected from the group consisting of compounds of cobalt and calcium into the nickel positive electrode (2), and a nickel-hydrogen storage battery using the same.
46 citations
TL;DR: In this paper, the surface of a Mm(Ni3.6Mn0.4Al0.3Co0.7)0.92 electrode was modified by electrodeposition of a foreign metal and the electrochemical characteristics of the resulting electrode were measured.
44 citations
TL;DR: In this paper, negative electrodes consisting of MmNi3.6Mn0.4Al0.3Co0.7 alloy in porous nickel substrate were modified by immersing them in an alkaline solution of potassium borohydride (KBH4).
43 citations
Patent•
31 Aug 1993
TL;DR: In this article, a hydrogen storage alloy with a formula of Mm1-a Ma Nib Mnc Cod Ale Xf has been revealed, where Mm is misch metal mainly containing La, Ce, Pr, Nd and the balance amount of unavoidable impurities; X is nitrogen, boron or the mixture thereof.
Abstract: The present invention discloses a hydrogen storage alloy having a formula of Mm1-a Ma Nib Mnc Cod Ale Xf wherein, Mm is misch metal mainly containing La, Ce, Pr, Nd and the balance amount of unavoidable impurities; M is titanium, zirconium or the mixture thereof; X is nitrogen, boron or the mixture thereof; and a is in the range of 0.01-0.2; b is in the range of 3.50-4.60; c is in the range of 0.20-0.60; d is in the range of 0.10-0.7; e is in the range of 0.1-0.5; f is in the range of 0.005-0.2; and b+c+d+e+f is in the range of 4.8-5.4.
43 citations
Patent•
27 Sep 1993TL;DR: In this article, a mixture of hydrogen and carbon dioxide is converted in a reactor into methane and/or methanol, and the carbon dioxide from the exhaust gas of fossil-fuelled energy (power) generation plants is used here.
Abstract: To store hydrogen energy, a mixture of hydrogen and carbon dioxide is converted in a reactor into methane and/or methanol. Preferably, the carbon dioxide from the exhaust gas of fossil-fuelled energy (power) generation plants is used here. Methane or methanol can be used as required as an energy source for vehicles, power stations and heating systems.
38 citations
Patent•
23 Aug 1993
TL;DR: In this paper, a hydrogen storage bed is made by distributing a hydride forming metal (10) within the polymeric material (8), which is in an uncured state.
Abstract: A hydrogen storage device (2) includes a vessel (4) and a hydrogen storage bed (6) disposed in the vessel (4). The hydrogen storage bed (6) includes a polymeric material (8) having a plurality of micropores less than about 1 nm in diameter and at least one hydride forming metal (10) imbedded within the polymeric material (8). The device also includes means for optically and thermally decomposing the metal hydride to release hydrogen and means for conveying hydrogen into and out of the storage device (2). The hydrogen storage bed (6) may be made by distributing a hydride forming metal (10) within the polymeric material (8) while the polymeric material (8) is in an uncured state. A metal hydride may be formed in the presence of hydrogen at a pressure such that the hydrogen bonds to the hydride forming metal (10) to form a metal hydride within the polymeric material (8). The hydrogen pressure may be reduced such that the metal hydride dissociates and any dissolved hydrogen escapes through the polymeric material (8), thereby forming a plurality of micropores less than about 1 nm in diameter. The micropores may be molded into the polymeric material (8) by cooling the polymeric material (8).
TL;DR: A few models about the activation of pure magnesium and magnesium alloys were reported also, for example, the cracking of surface oxide layer mechanism [5], the diffusion of surface oxygen atoms mechanism for pure magnesium [6], and the surface segregation and catalysis mechanism for Mg2Ni as discussed by the authors.
Abstract: Some mechanisms of the activation of hydrogen storage materials have been proposed, such as the surface segregation and catalysis mechanism [1], the surface oxide film cracking mechanism [2], the surface oxide film dissolution mechanism [3], the surface oxide layer permeation mechanism [4], etc. A few models about the activation of pure magnesium and magnesium alloys were reported also, for example, the cracking of surface oxide layer mechanism [5], the diffusion of surface oxygen atoms mechanism for pure magnesium [6], and the surface segregation and catalysis mechanism for Mg2Ni and Mg2Cu [7], yet the picture for the activation process of magnesium alloys remains unclear.
TL;DR: In this paper, the effect of impurities on the hydrogen storage capacity of magnesium powder was studied and the results were discussed and explanations for the observations are given. But the results of the experiments were limited to a mechanically produced magnesium powder with a mean particle diameter of 30 μm.
Patent•
05 Nov 1993
TL;DR: In this article, a metal hydride battery is used for storing hydrogen and a battery cell in another enclosure having the capability of fluid communication between the vessel and enclosure through in-line piping.
Abstract: A metal hydride battery includes a metal hydride vessel for storing hydrogen and a battery cell (12) in another enclosure having the capability of fluid communication between the vessel and enclosure through in-line piping (20). The in-line piping (20) includes a catalytic converter (24) and a molecular sieve dryer (30) for adsorbing water from the hydrogen being piped from the battery cell (12) enclosure to the hydrogen storage metal hydride vessel.
TL;DR: In this paper, the capacity of amorphous Ni-Zr alloys to absorb large amounts of hydrogen has been investigated in connection with their possible use for hydrogen storage, which makes them possible anodes in metal hydride-nickel hydroxide rechargeable batteries.
Abstract: The capacity of amorphous Ni-Zr alloys to absorb large amounts of hydrogen has been investigated recently in connection with their possible use for hydrogen storage. This property also makes them possible candidates as anodes in metal hydride-nickel hydroxide rechargeable batteries. The characteristic features of the electrochemical behavior of the amorphous Ni[sub 64]Zr[sub 36] alloy in alkaline media have been investigated. Changes occurring in both the physical state and the composition of the surface layer during chemical etching and electrochemical activation were studied by scanning electron microscopy, Auger electron spectroscopy, x-ray diffraction, and cyclic voltammetry. The kinetics of the hydrogen evolution reaction (HER) on the alloy under investigation was studied in terms of the cathodic polarization curves. The Tafel plots contain two different ranges: (i) a low-overpotential range, in which the slope of the linear [eta] versus log i is characteristic for charge transfer controlled processes; (ii) a high-overvoltage range, in which a combined mechanism, charge transfer and hydrogen diffusion into the bulk, is operative. To get information about the parameters influencing the hydrogen charging and discharging processes, chronopotentiometric experiments were performed. The changes of anodic overvoltage with time during constant current discharge were used to determine the electrochemical parameters i[submore » 0] and [beta], as well as the diffusion coefficients (D) of the H atoms in the bulk of the alloy.« less
TL;DR: In this article, the cycling lives of metal hydride electrodes using mischmetal (Mm)-based alloys were significantly impaired by a stoichiometric deviation to the Mm-deficient side, because elements such as manganese and aluminum were preferentially precipitated at grain boundaries.
TL;DR: In this article, the adsorption and absorption of hydrogen on and in various forms of supported and unsupported palladium were studied using heat-flow calorimetry, and it was found that the heat of formation and equilibrium for [beta]-hydride formation are functions of particle size.
Abstract: The adsorption and absorption of hydrogen on and in various forms of supported and unsupported palladium were studied using heat-flow calorimetry. The supports were found to have a tremendous effect on the nature of the hydrogen-palladium system. For palladium supported on silica or alumina, irreversible chemisorption was found to take place and be followed by bulk hydride formation. In contrast, it was found for carbon-supported particles that chemisorption does not take place and that the observed behavior could be explained by a model using only bulk hydride formation. It was further found that the heat of formation and equilibrium for [beta]-hydride formation are functions of particle size. It was not clear if surface adsorption takes place on unsupported palladium. 37 refs., 9 figs., 2 tabs.
Patent•
29 Jan 1993TL;DR: In this article, a sealed storage battery for portable power supply is improved by using metal oxide-hydrogen storage alloy to have a higher capacity and a smaller weight, where the battery has a structure which comprises a combination of a positive electrode having a high energy density in a wide range of temperature and consisting of a bulk high porosity body filled with an active material composed of solid solutions such as typical Co solid solution, oxide powders such as typically Ca(OH)₂ and ZnO, with an addition of graphite for rendering the electrode reaction effective.
Abstract: A sealed storage battery for use in portable power supply is improved by using metal oxide-hydrogen storage alloy to have a higher capacity and a smaller weight. The battery has a structure which comprises a combination of a positive electrode having a high energy density in a wide range of temperature and consisting of a bulk high porosity body filled with an active material composed of solid solutions such as typical Co solid solution, oxide powders such as typically Ca(OH)₂ and ZnO, with an addition of graphite for rendering the electrode reaction effective; and a high capacity negative electrode of hydrogen storage alloy having a reduced equilibrium hydrogen pressure, and where the aforementioned characteristics at high temperatures are further enhanced by an electrolyte suitable to high temperatures, short-circuits are prevented by a chemically stable separator, and a structure sealing a container and a safety vent is excellent in air-tightness and reliability.
TL;DR: The equilibrium pressure of the reaction between hydrogen and hydrogen storage alloys varies with temperature as mentioned in this paper, and the relation between compression ratio, thermal efficiency of compression and heat of hydride reaction is also discussed.
TL;DR: In this article, the feasibility of developing a man-portable power supply having a maximum power of 500 W, a stored energy capacity of 2000 W h and operating in environmental temperature conditions ranging from −40 to +40 °C is explored.
TL;DR: In this paper, the performance of composite materials with the general formula La2Mg17-xwt % LaNi5 (x=10, 20, 30 and 40) was investigated and the hydrogen storage capacity of these new composite materials was investigated.
Abstract: Alloys with the general formula La2Mg17-xwt % LaNi5 (x=10, 20, 30 and 40) have been synthesized and the hydrogen storage capacity of these new composite materials investigated. The materials were activated at temperatures of ∼ 360 °C under a hydrogen pressure of ∼ 33 kg cm−2. Optimum storage capacity of 5.24% in terms of pressure and composition was observed for La2Mg17-10 wt% LaNi5 at ∼ 400°C. This is one of the very highest hydrogen storage capacities known so far. The hydriding rate of La2Mg17 in the presence of LaNi5 is about 3–4 times that of La2Mg17 alone. In order to elucidate the role of LaNi5 in accelerating the hydrogen desorption rate of La2Mg17, the structural and microstructural characteristics of the composite material were carried out employing the XRD, SEM and EDAX techniques. The hydriding rate and hydrogen storage capacity are closely related to the microstructure and the types of phase present in the alloys.
TL;DR: In this article, a shape memory alloy was analyzed by neutron diffraction powder technique, and its reversible displacive transformations were checked for their long range ordering behaviour, and the cubic structured material was successfully hydrided by applying either an electrochemical procedure or H2 gas pressure under moderate conditions.
Abstract: NiTi, a shape memory alloy, was analysed by neutron diffraction powder technique, and its reversible displacive transformations were checked for their long range ordering behaviour. These transformations were controlled by other techniques as DSC, resistivity, and microanalysis. The cubic structured material was successfully hydrided by applying either an electrochemical procedure or H2 gas pressure under moderate conditions. The premartensite microstructure could play a favourable role on the hydridation reaction.
Patent•
24 May 1993
TL;DR: A hydrogen absorbing composition as mentioned in this paper comprises a porous glass matrix, made by a sol-gel process, having a hydrogen-absorbing material dispersed throughout the matrix A sol, made from tetraethyl orthosilicate, is mixed with a hydrogen absorbing material and solidified to form a porousglass matrix with the hydrogen absorption material dispersed uniformly throughout the matrices.
Abstract: A hydrogen absorbing composition The composition comprises a porous glass matrix, made by a sol-gel process, having a hydrogen-absorbing material dispersed throughout the matrix A sol, made from tetraethyl orthosilicate, is mixed with a hydrogen-absorbing material and solidified to form a porous glass matrix with the hydrogen-absorbing material dispersed uniformly throughout the matrix The glass matrix has pores large enough to allow gases having hydrogen to pass through the matrix, yet small enough to hold the particles dispersed within the matrix so that the hydrogen-absorbing particles are not released during repeated hydrogen absorption/desorption cycles
Patent•
28 Sep 1993
TL;DR: In this paper, the authors propose to improve energy efficiency as a system by imparting a function storing energy obtained by a solar cell, etc., to a fuel cell type electric vehicle.
Abstract: PURPOSE:To improve energy efficiency as a system by imparting a function storing energy obtained by a solar cell, etc., to a fuel cell type electric vehicle. CONSTITUTION:A fuel cell system A has the electrolytic device 100 of water, and the electrolytic device 100 is supplied with electrical energy by the reproduction of a solar cell installed to a car body and/or braking energy. Hydrogen gas generated by the electrolytic device 100 is stored in a high pressure tank 108 once, and a fuel cell 1 is supplied by utilizing the hydrogen system L1 of the fuel cell 1. When the internal pressure of the high pressure tank 108 is made higher hydrogen in the tank 108 is introduced into a hydrogen storage material tank 2 through a line 110, and stored in the hydrogen storage material tank 2.
Patent•
16 Mar 1993TL;DR: In this article, a hydrogen storage alloy consisting of base particles and fine particles consisting of at least one of metals, alloys, hydrophobic resins, catalyst materials, metal oxides having a particle size smaller than that of the base particles are employed as negative electrodes for alkaline storage batteries.
Abstract: A hydrogen storage alloy particles comprising base particles consisting of hydrogen storage alloy particles and fine particles consisting of at least one of metals, alloys, hydrophobic resins, catalyst materials, metal oxides having a particle size smaller than that of the base particles where the fine particles are very firmly bonded to the base particles are employed as negative electrodes for alkaline storage batteries. The bonding of the fine particles to the base particles is performed by a surface treatment so-called mechanofusion process (one of mechanochemical reaction process) where the base particles and the fine particles are subjected therebetween predominantly to a mechanical energy, practically those derived from the compression and attrition forces simultaneously to emboss the surfaces of the base particles and to allow the fine particles to be extended and bonded firmly under pressure onto the surfaces of the base particles, thereby coating at least a part of the surfaces of the base particles with the fine particles.
01 Jan 1993
TL;DR: In this article, performance evaluations coupled with cost analyses for four major alternatives for hydrogen storage show that storage on activated carbon compares quite favorably with the other three options: storage in pressurized cylinder, storage on metal hydride, and storage as liquid.
Abstract: In order to use hydrogen as an energy carrier in modern energy-use systems, it is necessary to find compact, efficient means for storing hydrogen for mobile and (or) stationary applications. Performance evaluations coupled with cost analyses for four major alternatives for hydrogen storage show that storage on activated carbon compares quite favorably with the other three options: Storage in pressurized cylinder, storage on metal hydride, and storage as liquid. Gravimetric, volumetric, and modified volumetric laboratory experiments can be used to assess the storage properties of various activated carbons and ultimately identify which carbons and which pressure and temperature windows meet desired storage requirements. 21 refs., 6 figs., 8 tabs.
TL;DR: In this article, the authors found that the formation of a cobalt compound on the alloy surface plus closer contact between particle enhanced the cyclic durability and discharge capacity of metal hydride anodes.
Abstract: This study attempted to find a simpler method for modifying hydrogen storage alloys that are used as anodes in Ni-MH batteries to prolong their cycle life. The alloy was modified by mechanical grinding with cobalt metal powder. A short grinding time yielded samples with a higher discharge capacity and longer cycle life than those of the alloy which was mixed with the cobalt powder without the mechanical treatment. However, prolonged grinding caused a decrease in the discharge capacity because of amorphization of the alloy by mechanical stress. The authors believed the formation of a cobalt compound on the alloy surface plus closer contact between particle enhanced the cyclic durability and discharge capacity of metal hydride anodes.
Patent•
30 Sep 1993
TL;DR: In this article, the authors proposed an explosion-proof countermeasures for a hydrogen filling station for filling hydrogen into a hydrogen automobile, where the roof of a car stop space is tilted and leaking very light hydrogen gas is promptly diffused to the atmosphere along a tilted lower surface of the roof.
Abstract: PURPOSE: To take explosion-proof countermeasures for a hydrogen filling station for filling hydrogen into a hydrogen automobile. CONSTITUTION: Roof 51 above a car stop space 2 is tilted, and leaking very light hydrogen gas is promptly diffused to the atmosphere along a tilted lower surface of the roof 51. By the first hydrogen storage tank 11, a large amount of hydrogen is stored in a condition stored in a hydrogen storage alloy. From the first hydrogen storage tank 11, the current necessary hydrogen gas is supplemented to the second hydrogen storage tank 12 of small capacity. Air in a high position of storage rooms 3, 4 for storing the hydrogen storage tanks 11, 12 is released to the atmosphere from ventilating fans 52, 53. The hydrogen storage tank 11 is cooled by a cooling unit 31, to store hydrogen in a stable condition. The hydrogen storage tanks 11, 12 can be also set up onto the roof 51 and can be also buried to be cooled in the ground. COPYRIGHT: (C)1995,JPO
TL;DR: In this article, the authors used X-ray photoelectron spectroscopy (XPS) and Auger electron spectrograms (AES) to analyze the surface of a hydrogen storage alloy electrode.