ISSN:
0935-9648
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
A New class of highly electroactive hydride-forming compounds is described as well as simple metallurgical methods for producing these materials. The new type of metal alloys consist of two different crystallographic phases. The bulk phase is responsible for hydrogen storage and is formed by the stable multicomponent “standard alloy” of the AB5 type. The second phase homogeneously decorates the surface of the bulk phase and ensures a high electrocatalytic activity. In composing this second phase no precious metals are required, but carefully selected combinations of transition metals can be used. Very high overall exchange currents and discharge efficiencies are obtained, even at low temperature. Cycle life and storage capacities are comparable with the values found for the standard alloy. Substituting small amounts of B-metals with highly electrocatalytic elements was also found to be effective in improving the electroactivity of AB5 compounds. However, a drawback of this method is that significant improvements are obtained only when precious metals are incorporated. Double-phase materials must therefore be considered as more serious candidates for use in future nickel/metal-hydride batteries with high charge/discharge capability.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/adma.19910030704
