Hydro-quebec

Mcgill University

Jacques Huot

Robert Schulz

Sabin Boily

Daniel Guay

Guy Lalande

Guoxian Liang

John O Strom-Olsen

Leszek Zaluski

Alicja Zaluska

Andre Van Neste

Salim Bouaricha

André Van Neste

Marie-Chantal Denis

Guoxiang Liang

Reynald Rioux

Jean-Pol Dodelet

The invention concerns a method for preparing a nanocomposite based on magnesium and another element or compound known to absorb hydrogen and hardly miscible when ground with magnesium or its hydride, such as vanadium, titanium or niobium. The method is characterised in that it consists in submitting magnesium or a compound based on magnesium known to absorb hydrogen to hydrogenation to obtain the corresponding hydride in powder form. Said resulting powder hydride is then mixed with the other element or compound or a hydride of said other element or compound and the resulting mixture is subjected to intense mechanical grinding until the corresponding nanocomposite is obtained in the form of a hydride. Finally, if necessary, the resulting nanocomposite is subjected to hydrogen desorption. The invention also concerns the resulting nanocomposite based on Mg, which has the advantage of being inexpensive and highly efficient for storing hydrogen owing to its microstructure (that is owing to the nature of its interfaces and the spatial distribution of its constituents) which is extremely fine and provides an excellent synergistic effect between Mg and the other element or compound.

Nanocomposites with activated interfaces prepared by mechanical grinding of magnesium hydrides and use for storing hydrogen

Disclosed is a method for rapidly carrying out a hydrogenation of a material capable of absorbing hydrogen. It was discovered that when a powder of a material capable of absorbing hydrogen is ground under a hydrogen pressure, not at room temperature but at a higher temperature (about 300&deg; C. in the case of magnesium) and in the presence of a hydrogenation activator such as graphite and optionally a catalyst, it is possible to transform completely the powder of this material into a hydride. Such a transformation is achieved in a period of time less than 1 hour whereas the known methods call for periods of time as much as 10 times longer. This is an unexpected result which gives rise to a considerable reduction in the cost of manufacture of an hydride, particularly MgH .

Method of rapidly carrying out a hydrogenation of a hydrogen storage material

The invention concerns an apparatus for the titration and circulation of gases to determine metal hydride storing properties, with improved response time, greater dynamic range in terms of the usable amount of powder and the maximum pressure accessible and increased sensitivity. The invention also concerns a circulating apparatus considerably reducing the time for analysing and determining the properties of absorbent and adsorbent materials during a large number of adsorption-desorption cycles. Both sets of apparatus are provided with a reference tube inside their oven, near the sample-holder. Said sample-holder tube and reference tube are connected on either side of the differential pressure sensor, thereby considerably enhancing the overall performance of the titration system.

Apparatus for titration and circulation of gases and circulation of an absorbent or adsorbent substance

An improved method is disclosed for producing gaseous hydrogen by subjecting a metal or a metal hydride to a chemical reaction. In this method, the metal or metal hydride subjected to the chemical reaction is nanocrystalline. Indeed, it has been found that when, instead of using conventional metal hydrides (Mg-based or others), use is made of a metal or metal hydride that is or has been subjected to intensive mechanical deformations, such as a metastable nanocrystalline metal hydride, then the chemical reaction, especially hydrolysis, will take place much more readily, at a much higher rate and, most of the time, up to completion.

Method for producing gaseous hydrogen by chemical reaction of metals or metal hydrides subjected to intense mechanical deformations

Disclosed is a nanocrystalline composite useful for hydrogen storage, which provides optimum hydrogenation conditions along with high hydrogen storage capacity. This composite is the combination of at least one high temperature metal hydride such as Mg or Mg.sub.2 Ni, which has a high hydrogen storage capacity by weight but requires high temperatures for hydrogen absorption and desorption, with at least one low temperature metal hydride such as FeTi, LaNi.sub.5, Nb, Mn or Pd, which has a low hydrogen storage capacity by weight but does not require high temperatures for hydrogen absorption and desorption. The high and low temperature metal hydrides are in direct contact with each other and each in the form of a nanocrystalline powder or layer. This composite is particularly useful as a hydrogen supply source for hydrogen-fueled vehicles.

Nanocrystalline composite for hydrogen storage

Leached nanocrystalline materials having a high specific surface are particularly useful for storing hydrogen or as catalysts or electrocatalysts in the manufacture electrodes, especially for fuel cells. Such materials can be manufactured by preparing a nanocrystalline material consisting of a metastable composite or alloy of at least two different chemical elements. To be nanocrystalline, this material must have a crystalline structure with the grain size lower than 100 nm. Then, the so prepared nanocrystalline material can be subjected to a leaching treatment in order to eliminate partially or totally one of the elements of the composite or alloy. This leaching results in nanocrystalline materials having a porous structure and, thereby, the requested high specific surface.

Leached nanocrystalline materials process for manufacture of the same,

A process is described for preparing a nanocrystalline powder of an alloy of at least two metals by an intensive mechanical grinding step performed upon powders of the metals which make up the alloy. The grinding is performed at atmospheric pressure under an inert atmosphere, and is carried out at a temperature in the range of 100.degree.-400.degree. C. In this manner, one obtains crystallites of the alloy having a grain size lower than 100 nm by grinding for a period of time lower by about an order of magnitude than the time necessary to achieve this grain size by a similar grinding step carried out at ambient temperature.

Growing community of inventors

Boucherville, Canada

Jacques Huot