MXPA97007964A - Improved electrochemical hydrogen storage alloys for nickel metal hydride batteries - Google Patents

Abstract

A disordered electrochemical hydrogen storage alloy comprising:(Base Alloy)aCobMncFedSne where the Base Alloy comprises 0.1 to 60 atomic percent Ti, 0.1 to 40 atomic percent Zr, 0 to 60 atomic percent V, 0.1 to 57 atomic percent Ni, and 0 to 56 atomic percent Cr;b is 0 to 7.5 atomic percent;c is 13 to 17 atomic percent;d is 0 to 3.5 atomic percent;e is 0 to 1.5 atomic percent;and a + b + c + d + e=100 atomic percent.

Description

ALLOYS OF ELECTROCHEMICAL HYDROGEN STORAGE.

IMPROVED FOR NICKEL METAL HYDRIDE BATTERIES DESCRIPTION OF THE INVENTION The present invention is a continuation in part of U.S. Patent Application No. 08 / 136,066 filed October 14, 1993. U.S. Patent Application No. 08 / 136,066 is a continuation. in part of U.S. Patent No. 5,277,999 (filed as U.S. Patent Application No. 07 / 934,976 on August 25, 1992). U.S. Patent No. 5,277,999 is a continuation in part of U.S. Patent No. 5,238,756 (filed as U.S. Patent Application No. 07 / 746,015 on August 14, 1991). U.S. Patent No. 5,238,756 is a continuation in part of U.S. Patent No. 5,104,617 (filed as U.S. Application No. 07 / 515,020 on April 26, 1990). The present invention relates to electrochemical hydrogen storage alloys and rechargeable electrochemical cells using these alloys. More particularly, the invention relates to rechargeable cells and batteries having negative electrodes formed from multi-component electrochemical hydrogen storage alloys. Cells incorporating these alloys have performance characteristics, such as energy density, charge retention, life cycle, and low temperature operation, which are significantly improved over known rechargeable cells using hydrogen storage alloys . The present invention also discloses unique alloys that utilize significantly reduced amounts of Co without a loss in performance. The rechargeable cells that use a positive electrode of nickel hydroxide and a negative hydrogen storage electrode for metal hydride ("metal hydride cells") are known in the art.

When an electrical potential is applied between the electrolyte and a metal hydride electrode in a metal hydride cell, the negative electrode material (M) is charged through the electrochemical absorption of the hydrogen and the electrochemical evolution of an ion hydroxyl; when unloaded, the stored hydrogen is released to form a water molecule and develop an electron: Load M + H20 + e_ < > MH + OH "discharge The reactions that occur in the positive electrode of a nickel metal hydride cell are also reversible.Most metal hydride cells use a positive electrode of nickel hydroxide. and discharge are presented in a positive electrode of nickel hydroxide: Load Ni (OH) 2 + OH '< --- > NiOOH + H20 + e "discharge In a metal hydride cell having a positive nickel hydroxide electrode and a negative hydrogen storage electrode, the electrodes are typically separated through a nylon or felt separator, polypropylene, not The electrolyte is usually an alkaline aqueous electrolyte, for example, from 20 to 45% by weight of potassium hydroxide.The first hydrogen storage alloys that were investigated as battery electrode materials were TiNi and LaNi. years to study these simple binary intermetallics, since they were known to have a suitable hydrogen-bonding strength for use in electrochemical applications.However, despite extensive efforts, the researchers found that these intermetallics were extremely inadequate and of electrochemical value marginal due to a variety of harmful effects such as low discharge, ox oxidation, corrosion, poor kinetics, and poor catalysis. These simple alloys for battery applications reflect the traditional deviation of battery developers towards using pairs of individual elements of crystalline materials such as NiCd, NaS, LiMS, ZnBr, NiFe, NiZn, and Pb acid. In order to improve the electrochemical properties of binary intermetallics, while maintaining hydrogen storage efficiency, workers began to modify the TiNi and LaNi systems. . The modification of TiNi and LaNi5 was initiated by Stanford R. Ovshins and at Energy Conversion Devices (ECD) of Troy, Michigan. Ovshinsky and his group at ECD showed that confidence in simple, relatively pure compounds was a major disadvantage of the prior art. The prior art determined that the catalytic action depends on the surface reactions at sites of irregularities in the crystal structure. It was found that relatively pure compounds have a relatively low density of hydrogen storage sites, and the type of available sites occurred by accident and were not designed in the volume of the material. In this way, the hydrogen storage efficiency and the subsequent release of hydrogen was determined to be less substantial than would be possible if a large number and variety of active sites were available.

Ovshinsky previously found that the number of surface sites can be significantly increased by making an amorphous film that resembles the surface of relatively pure, desired materials. As Ovshinsky explained in Principi es and Applications of Amorphici ty, Structural Change, and Optical Information Encoding, 42 Journal De Physique to C4-1096 (October 1981): The term amorphous is a generic term that refers to the lack of evidence X-ray diffraction of large scale periodicity and is not a sufficient description of a material. To understand amorphous materials, several important factors must be considered: the type of chemical union, the number of bonds generated by the local order, that is, their coordination, and the influence of the entire local environment, both chemical and geometric, after the result of variable configurations. The amorphous character is not determined by random bundles of atoms seen as hard spheres nor is the amorphous solid merely a host with atoms embedded randomly. Amorphous materials must be seen as being composed of an interactive matrix, whose electronic configurations are generated by free energy forces that can be specifically defined by the chemical nature and coordination of the constituent atoms. Using elements of multiple orbits and various preparation techniques, normal relaxations reflecting equilibrium conditions can be simulated and, due to the three-dimensional freedom of the amorphous state, they make completely new kinds of amorphous materials, chemically modified materials. Once the amorphous aspect has been understood as a means to introduce surface sites into a film, it was possible to produce "disturbances" in a planned way, not only in amorphous materials, but also in crystalline materials; "disorders" that represent the entire spectrum of local effects such as porosity, topology, crystallites, site characteristics and distances between sites. In this way, instead of looking for material modifications that could produce ordered materials that have a maximum number of surface irregularities accidentally existing, the Ovshinsky group at ECD began to construct "deranged" materials where desired irregularities could develop. See United States Patent 4,623,597, the description of which is incorporated herein by reference. The term "deranged" as used herein, corresponds to the meaning of the term as used in the literature, such as the following: A deranged semiconductor can exist in several structural states. This structural factor constitutes a new variable with which the physical properties of the [material] can be controlled. In addition, the structural disorder opens the possibility of preparing new compositions and mixtures in a metastable state that exceed the limits of thermodynamic equilibrium. Therefore, the following is observed as an aspect of additional distinction. In many depleted [materials], it is possible to control the short scale order parameter and in this way obtain drastic changes in the physical properties of these materials, including numbers of new elements of forced coordination. MR . Ovshinsky, The Shape of Disorder, 32 Journal of Non-Crystalline Solids at 22 (1979) (emphasis added). The "short scale order" of these deranged materials is further explained by Ovshinsky in The Chemical Basis of Amorphici ty. Structure and Function, 26: 8-9 Rev. Roum. Phys at 893-903 (1981): The order of short scale is not conserved ... In fact, when the crystal symmetry is destroyed, it becomes impossible to retain the order of short scale. The reason for this is that the order of short scale is controlled by the force fields of electron orbits, therefore, the environment must be fundamentally different in corresponding crystalline and amorphous solids. In other words, this is the interaction of local chemical bonds with their surrounding environment, which determines the electrical, chemical and physical properties of the material and these can never be the same in amorphous materials as they are in crystalline materials ... Orbital relationships that can exist in three-dimensional space in amorphous but non-crystalline materials are the new geometric bases, many of which are inherently anti-crystalline by nature. Bond distortions and displacement of atoms may be an adequate reason to cause amorphous character in individual component materials. But to understand sufficiently the amorphous aspect, one must understand that the three-dimensional relationships inherent in the amorphous state, for which the internal topology is generated, incompatible with the translational symmetry of the crystal structure network ... What is important in the amorphous state is the fact that one can make an infinity of materials that have no crystalline counterpart, and that even those who have it are mainly similar in chemical composition. The spatial and energetic relationships of these atoms may be completely different in amorphous and crystalline forms, although their chemical elements may be the same ...

The short or local scale order is elaborated in U.S. Patent 4,520,039 by Ovshinsky, entitled Compositional and Varied Ma terials and Method for Synthesizing the Ma terials, the contents of which are incorporated herein for reference. This patent discusses how decontaminated materials do not require any periodic local order and how, using Ovshinsky's techniques, spatial placement and orientation of atoms or similar or different groups of atoms is possible with such increased precision and control of local configurations that it is possible to produce new phenomena coalitionally. In addition, this patent argues that the atoms used do not need to be restricted to "band d" or "band f" atoms, but can be any atom where the controlled aspects of the interaction with the local environment play a significant, physical, electrically or chemically, in order to affect the physical properties and therefore the functions of the materials. These techniques result in means for synthesizing new materials, which are disrupted in several different ways, simultaneously. By forming metal hydride alloys of such deranged materials, Ovshinsky and his group were able to greatly increase the reversible hydrogen storage characteristics required for efficient battery and economic applications, and produce batteries that have a high density energy storage capacity. efficient reversion, high electrical efficiency, bulky storage of hydrogen without change or structural poisoning, a long life cycle, and a deep discharge capacity. The improved characteristics of these alloys result in the development of local chemical order and hence the local structural order by the incorporation of selected modifying elements in a host matrix. Undrained metal hydride alloys have a substantially increased density of catalytically active sites and storage sites compared to simple, ordered crystalline materials. These additional sites are responsible for the improved electrochemical charge / discharge efficiency and an increase in electrical energy storage capacity. The nature and number of storage sites can still be designed independently of the catalytically active sites. More specifically, these alloys are developments to allow bulky storage of dissociated hydrogen atoms to bond strengths within the appropriate reversion capacity scale for use in secondary battery applications.

Based on the primary principles described above7 some of the most efficient electrochemical hydrogen storage materials were formulated. These included the modified LaNi5 type, as well as the TiVZrNi type active materials. Ti-V-Zr-Ni active materials are described in U.S. Patent No. 4,551,400 ("the 400 Patent"), the disclosure of which is incorporated herein by reference. These materials reversibly form hydrides in order to store hydrogen. All of the materials used in the 400 patent use a generic Ti-V-Ni composition, wherein at least Ti, V and Ni are present with at least one or more of Cr, Zr, and Al. Patent 400 are multi-phase materials, which may contain, but are not limited to, one or more TiVZrNi type phases with a C14 and C15 type crystal structure. The following formulas are specifically described in the 400 patent: (TiV2-xNix> l-yMy where x is between 0.2 and 1.0, and is between 0.0 and 0.2, and M = Al or Zr; Ti2-xZrxV4-yNiy wherein Zr is partially substituted for Ti; x is between 0.0 and 1.5; and y is between 0.6 and 3.5; Y Til-xCrxV2-yNiy where Cr is partially substituted by Ti; x is between 0.0 and 0.75; and y is between 0.2 and 1.0. Other Ti-V-Zr-Ni alloys can also be used for a negative rechargeable hydrogen storage electrode. One of these families of materials are those described in U.S. Patent No. 4,728,586 ("the 586 Patent") by Venkatesan, Reichman, and Fetcenko for Enchanced Cherge Retention Electrochemical Hydrogen Storage Alloy s and an Enchanced Charge Retention The ectrochemi Cell lime, the description of which is incorporated for reference. Patent 586 discloses a specific subclass of these Ti-V-Ni-Zr alloys comprising Ti, V, Zr, Ni and a fifth component, Cr. In a particularly preferred illustration of the 586 patent, the alloy has the composition (Ti2-xZrxV4-y Vl-zCrz where x is from 0.00 to 1.5, and is from 0.6 to 3.5, z is an effective amount less than 0.20.These alloys can be seen stoichiometrically as comprising 80 atomic percent of a portion of V-Ti-Zr-Ni and up to 20 atomic percent of Cr, where the ratio of (Ti + Zr + Cr + optional modifiers) to (Ni + V + optional modifiers) is between 0.40 and 0.67. , mentions the possibility of additives and modifiers beyond Ti, V, Zr, Ni and Cr that are components of alloys, and generally discusses specific additives and modifiers, the interaction amounts of these modifiers, and the particular benefits that may be expected. The alloy family of V-Ti-Zr-Ni described in Patent 586 has an inherently higher discharge rate capability than the previously described alloys This is the result of substantially larger surface areas in the interface of m etal / electrolyte for electrodes made of V-Ti-Zr-Ni materials. The roughness factor of the surface (total surface area divided by the geometric surface area) of the V-Ti-Zr-Ni alloys is approximately 10,000. This value indicates a very high surface area and is supported by the inherently high speed capacity of these materials. The surface roughness characteristic of the metal / electrolyte interface is a result of the deranged nature of the material. Since all constituent elements, as well as many alloys and phases thereof, are present throughout the material, they are also represented on the surface and in the cracks that form at the metal / electrolyte interface. In this way, the characteristic surface roughness is descriptive of the interaction of the physical and chemical properties of the host metals as well as the alloys and crystallographic phases of the alloys, in an alkaline environment.

These chemical, physical and crystallographic, microscopic parameters of the individual phases within the hydrogen storage alloy material are believed to be important in determining their macroscopic electrochemical characteristics. In addition to the physical nature of its rough surface, it has been observed that V-Ti-Zr-Ni alloys tend to achieve a stable state surface composition and a particle size. This phenomenon is described in U.S. Patent No. 4,716,088. This subcomposition of fixed state surface is characterized by a relatively high concentration of metallic nickel. These observations are consistent with a relatively high rate of removal through precipitation of the titanium and zirconium oxides from the surface, and at a much lower rate of solubilization of the nickel, providing a degree of porosity to the surface. The resulting surface appears to have a higher concentration of nickel than would be expected from the bulky composition of the negative hydrogen storage electrode. Nickel in the metallic state is electrically conductive and catalytic, imparting these properties to the surface. As a result, the surface of the negative hydrogen storage electrode is more catalytic and conductive than if the surface contained a higher concentration of insulation oxides. In contrast to the Ti-V-Zr-Ni based alloys described above, the modified LaNi5-type alloys have generally been considered as "ordered materials" having a different chemistry and microstructure, and exhibiting different electrochemical characteristics compared to the alloys of Ti-V-Zr-Ni. However, the analysis reveals, while the LaNi type alloys? formerly unmodified were ordered materials, highly modified LaNi5 alloys, more recently developed, are not. The operation of the LaNi materials? Previous orders were deficient. Nevertheless, the alloys of LaNi? modified at present have a high degree of modification (ie, since the number and number of elementary modifiers has increased) and the operation of these alloys has been significantly improved. This is due to the disorder contributed by the modifiers, as well as their electrical and chemical properties. This evolution of modified LaNic-type alloys forms a specific class of "ordered" materials to the current, multi-component, "deranged" multi-component alloys that are now very similar to the Ti-V-Zr-Ni alloys that are shown in the following patents: (i) U.S. Patent No. 3,874,928, (ii) U.S. Patent No. 4,214,043; (iii) U.S. Patent No. 4,107,395, (iv) U.S. Patent No. 4,107,405; (v) United States Patent No. 4,112,199; (vi) U.S. Patent No. 4,125,688: (vii) U.S. Patent No. 4,214,043; (viii) U.S. Patent No. 4,216,274; (ix) U.S. Patent No. 4,487,817; (x) U.S. Patent No. 4,605,603; (xii) U.S. Patent No. 4,696,873; and (xiii) U.S. Patent No. 4,699,856. (These references are discussed extensively in U.S. Patent No. 5,096,667 and this discussion is incorporated specifically by reference). Simply established, in type alloys LaNi5 modified, such as alloys of type Ti-V-Zr-Ni, as the degree of modification is increased, the role of the initially ordered base alloy becomes of secondary importance compared to the properties and the disorder attributable to particular modifiers . In addition, the analysis of current multiple components of type of modified LaNi5 alloys, indicate that these alloys are modified following the guidelines established by TiVZrNi type systems. The highly modified LaNic type alloys are identical to the TiVZrNi type alloys in that both are deranged materials -characterized by multiple components and multiple phases.

In this way, there is no longer any significant distinction between these two types of multi-component, multi-phase alloys. Since the hydrogen storage alloys of the prior art frequently incorporate several individual modifiers and combinations of modifiers to improve their performance characteristics, there is no clear teaching of the role of any individual modifier, the interaction of some modifier with other components of the alloy or the effects of the modifier in the specific operations parameters. Since the highly modified LaNic alloys were analyzed within the context of the ordered crystalline materials, the effect of these modifiers, in particular, was not clearly understood. Prior art hydrogen storage alloys have generally been able to provide improved performance attributes, such as life cycle, discharge velocity, discharge voltage, polarization, self discharge, low temperature capacity, and low temperature voltage. However, alloys of the prior art produced cells that exhibit a quantitative improvement in one or two performance characteristics at the expense of a quantitative reduction in other performance characteristics. As a rule, the main operating characteristics of these cells are sometimes only slightly better than the comparable characteristics of other cell types such as NiCds. In this way, all the cells produced from the alloys of the prior art were special purpose cells, whose performance characteristics, both good and bad, represented an engineering commitment and, therefore, were developed closely to the intended use of the cell. . BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows regions enriched with nickel at the oxide interface. An object of the present invention are hydrogen storage alloys that exhibit improved capacity. These and other objects of the present invention will be met through the following electrochemical hydrogen storage alloys and methods for forming such alloys: A deranged electrochemical hydrogen storage alloy comprising: (Base Alloy) aCobMncFedSne wherein the Alloy Base comprises from 0.1 to 60 atomic percent of Ti, from 0.1 to 40 atomic percent of Zr, from 0 to 60 atomic percent of b, from 0.1 to 57 atomic percent of Ni and from 0 to 56 atomic percent of Cr; b is from 0 to 7.5 atomic percent; c is from 13 to 17 atomic percent; d is from 0 to 3.5 atomic percent, e is from 0 to 1.5 atomic percent and a + b + c + d + e = 100 atomic percent. An electrochemical hydrogen storage alloy having an alloy surface enriched with Ni at the oxide interface. A method for forming an electrochemical hydrogen storage alloy having regions enriched with Ni at the oxide interface comprising the steps of: formulating an electrochemical hydrogen storage alloy containing components that are preferentially corroded during activation; and activate the alloy to produce regions enriched with Ni. A method for forming an electrochemical hydrogen storage alloy having regions enriched with Ni at the oxide interface comprising the steps of: formulating a first electrochemical hydrogen storage alloy; formulating a second alloy containing components that are preferably corroded during activation to leave regions enriched with Ni; forming an alloy mechanically of the first alloy and the second alloy; and activating the first and second alloys mechanically formed in the alloy. An electrochemical hydrogen storage cell comprising: A negative electrode composed of a deranged electrochemical alloy having the following composition: (Base Alloy) aC? JDMncFecjSne wherein the Base Alloy comprises from 0.1 to 60 atomic percent Ti, 0.1 at 40 atomic percent of Zr, from 0 to 60 atomic percent of b, from 0.1 to 57 atomic percent of Ni and from 0 to 56 atomic percent of Cr; b is from 0 to 7.5 atomic percent; c is from 13 to 17 atomic percent; d is from 0 to 3.5 atomic percent, e is from 0 to 1.5 atomic percent and a + b + c + d + e = 100 atomic percent. The deranged metal hydride alloy materials of the present invention are designed to have unusual bi-or three-dimensional electronic configurations, varying the three-dimensional interactions of constituent atoms and their various orbits. The disorder in these alloys comes from the compositional, positional and translational relationships, as well as the disorder provided by the number, position and size of crystallites of the atoms that are not limited by the symmetry conventional crystallizes in their freedom to interact. This disorder can be of an atomic nature in the form of a compositional or configurational disorder provided through the volume or in numerous regions of the material. These deranged alloys have a lower order than the highly ordered crystalline structures, which provide the individual phase materials such as those used for many of the electrode alloys in the prior art. The types of deranged structures, which provide the local structural chemical environments for improved hydrogen storage characteristics in accordance with the present invention, are multi-component polycrystalline materials lacking long-range compositional order; microcrystalline materials; amorphous materials that have one or more faces; multi-phase materials containing both amorphous and crystalline faces; or mixtures thereof. The structure for the deranged metal hydride alloys is a host matrix of one or more elements. The host elements are generally chosen to be hydride formers and may be lightweight elements. The elements of the host matrix can be, for example, based on LaNi or TiNi. The host matrix elements are modified by incorporating selected modifying elements, which may or may not be hydride formers.

The inventors have found through extensive analysis that considering the initial host matrix materials, when numerous modifying elements are introduced (such as those described in the present invention), the result is a deranged material having superior electrochemical properties. The improvement in electrochemical properties is due to an increase in the number and spectrum of catalytically active, hydrogen storage sites. In particular, multiple orbital modifiers, for example transition elements, provide an enormously increased number of storage sites due to the various connection configurations available. This results in an increase in energy density. The modification that results from an unbalanced material that has a high degree of disturbance, provides unique binding configurations, orbital overlap and therefore a spectrum of binding sites. Due to the different degrees of orbital overlap and deranged structure, an insignificant amount of structural position networks occurs during the load / unload cycles, or during rest periods, resulting in a long cycle and storage life. The storage characteristics of hydrogen and other electrochemical characteristics of the electrode materials of the present invention can be altered in a controlled manner depending on the type and amount of the host matrix material and modifying elements selected to make the negative electrode materials. The negative electrode alloys of the present invention are resistant to degradation by poisoning due to the increased number of selectively designed and catalytically active storage sites, which also contribute to the long life cycle. Also, some of the designated sites in the material can join with and resist poisoning without affecting the active hydrogen sites. The materials thus formed have a very low self-discharge and therefore a good storage life. As discussed in U.S. Patent No. 4,716,088 (the contents of which are specifically incorporated for reference) it is known that the stable state surface composition of V-Ti-Zr-Ni alloys can be characterized as having a concentration relatively high nickel metal. One aspect of the present invention is a significant increase in the frequency of occurrence of these nickel regions as well as a more pronounced localization of these regions. More specifically, the materials of the present invention have regions enriched with nickel of 50-70 A in diameter distributed through the oxide interface and varying in the neighborhood of 2-300 A, preferably 50-100 A, region to region. This is illustrated in Figure 1, where the nickel 1 regions are shown as appearing as grains on the surface of the oxide interface 2 at 178,000 X. As a result of the increase in the frequency of occurrence of these nickel regions, The materials of the present invention exhibit significantly increased catalysis and conductivity. The increased density of the Ni regions in the present invention provides powder particles having a surface enriched with Ni. Prior to the present invention, Ni enrichment was attempted unsuccessfully using microencapsulation. The Ni encapsulation method results in the decomposition of a Ni layer with a thickness of approximately 100 Á at the metal-electrolyte interface. Said quantity is excessive and results in no improvement in the operating characteristics. The Ni-enriched regions of the present invention can be produced through two general manufacturing strategies: 1) Specifically formulating an alloy having a surface region that is preferentially corroded during activation to produce the Ni-enriched regions described. Without wishing that this bound by theory, it is believed, for example, that Ni is in association with an element such as Al in specific surface regions and that this element preferentially corrosion during activation, leaving the regions enriched with Ni described above. "Activation" as used herein, specifically refers to "chemical etching" or other methods for removing excess oxides, such as those described in U.S. Patent No. 4,716,088, as applied to the electrode, the finished electrode or at any point between these in order to improve the hydrogen transfer rate. 2) Carry out mechanically the alloy of an alloy secondary to a hydride battery alloy, where the secondary alloy will preferentially be corroded to leave enriched nickel regions. An example of such a secondary alloy is NiAl. The alloys that have regions enriched with Nor can they be formulated for each known type of hydride battery alloy system, including, but not limited to, Ovonic, TiVZrNi type, modified LaNi5 type, mischmetal, and LaNi5 alloys as well as the Mg alloys described in the Patent Application. United States Comp. No. 08 / 259,793. More specific examples of hydride alloys that can be specifically formulated or mechanically formed in alloys with a second alloy as described in 1) and 2) above, to produce regions enriched with Ni are as follows: Alloys represented by the formula ZrMnwV? MyNiz , where M is Fe or Co, and, x, y and z are molar ratios of the respective elements where 0.4 sws 0.8, 0.1 sxs 0.3, O sys 0.2, 1.0 = z = 1.5 ys 2.0 = w + x + y + z = 2.4. The alloys corresponding substantially to the formula LaNic in which one of the components La or Ni is replaced by a metal M selected from groups la, II, III, IV, and Va of the Periodic Table of the Elements other than lanthanides, in an atomic proportion, which is greater than 0.1% and less than 25%. The alloys that have the formula TiV2_? Ni ?, where x = 0.2 to 0.6. The alloys that have the formula TiaZrj =) NicCrcjM ?, where M is Al, Si, V, Mn, Fe, Co, Cu, Nb, Ag, or Pd, 0.1 = a = 1.4, 0.1 = b = 1.3 , 0.25 < c = 1.95, 0.1 = d = 1.4 a + b + c + d = 3 and 0 = x = 0.2. The alloys that have the formula ZrMo ^ Ni where d = 0.1 to 1.2 and e = 1.1 to 2.5. The alloys that have the formula Ti1_? Zr? Mn2_y_zCr Vz where 0.05 s x = 0.4, O = y s 1.0 and 0 < < 0.4. The alloys having the formula LnMc wherein Ln is at least one lanthanide metal and M is at least one metal selected from the group consisting of Ni and Co. The alloys comprising at least one transition metal forming 40-75% by weight of the chosen alloy of groups II, IV and V of the Periodic System, and at least one additional metal, developing the rest of the alloy, formed in alloy with at least one transitional metal, this additional metal chosen from the group consisting of Ni, Cu, Ag, Fe, and Cr-Ni steel. Alloys that comprise a main texture of the Mn-Ni system; and a plurality of compound phases wherein each compound phase is segregated into the main texture, and wherein the volume of each of the compound phases is less than about 10 μm-. The most preferred alloys having Ni-enriched regions are alloys having the following composition: (Base Alloy) aC?];) MncFecjSne wherein the Base Alloy comprises from 0.1 to 60 atomic percent of Ti, from 0.1 to 40 atomic percent of Zr, 0 to 60 atomic percent of b, 0.1 to 57 atomic percent of Ni, and 0 to 56 atomic percent of Cr; b is from 0 to 7.5 atomic percent; c is from 13 to 17 atomic percent; d is from 0 to 3.5 atomic percent; e is from 0 to 1.5 atomic percent; and a + b + c + d + e = 100 atomic percent. The production of the Ni regions of the present invention are consistent with a relatively high removal rate through the precipitation of the titanium and zirconium oxides from the surface and at a much lower rate of solubilization of the nickel, providing a degree of porosity to the surface. The resulting surface has a higher concentration of nickel than would be expected from the bulky composition of the negative hydrogen storage electrode. Nickel in the metallic state is electrically conductive and catalytic, imparting these properties to the surface. As a result, the surface of the negative hydrogen storage electrode is more catalytic and conductive than if the surface contained a higher concentration of insulation oxides. An important consideration in formulating the alloys of the present invention involves the formulation of specific alloys that have the proper balance of corrosion and passivation characteristics to form exceptional electrochemical alloys. In accordance with the present invention, this method involves choosing modifiers from those set forth in Table 1, below.

In general, when the elements described in Table I are added as modifiers, they make the following contributions to the final alloy mixture: i) in group I, the elements alter the corrosion as well as the storage and binding characteristics; ii) in groups II, V, Ti and Zr alter both resistance and corrosion, and Cr, Al, Fe, and Sn alter corrosion, passivation and catalysis; iii) in group III, all elements are glass formers and affect crystal lattice formation; and iv) in group IV, Cu, Th, Si, Zn, Li, La, and F affect the disorder and alter the density of the state. As used herein, the term "Base Alloy" refers to a deranged alloy having a base alloy (as this term is described in U.S. Patent No. 4,551,400) which is an alloy of deranged multiple components having at least one selected structure from the group consisting of amorphous, microcrystalline, polycrystalline and any combination of these structures. The terms "amorphous", "microcrystalline", and "polycrystalline" are used as defined in U.S. Patent No. 4,623,597, the contents of which are incorporated by reference. The alloys of the present invention are not limited to any particular structure. Preferably, the materials of the present invention are classified as having a disrupted structure and encompass materials that have been commonly referred to by a variety of other terms such as type AB, TiVZrNi, modified LaNi5, LANic, mischmetal, Laves phase of C14, C15 , etc. More specific examples of base alloys are the following: An alloy represented by the formula ZrMnwV? M Niz, where M is Fe or Co, and W, x, y and z are molar ratios of the respective elements, where 0.4 w = 0.8 , 0.1 = x < 0.3, 0 = y < 0.2, 1.0, < z = 1.5, and 2.0 < w + x + y + z < 2.4. An alloy corresponding substantially to the formula LaNic, wherein one of the components La or Ni is replaced by a metal M selected from groups la, II, III, IV and Va of the Periodic Table of the Elements other than lanthanides, in an anatomical proportion which is greater than 0.1% and less than 25%. An alloy that has the formula TiV2_? Ni ?, where x = 0.2 to 0.6. An alloy that has the formula TiaZrbNicCrdM ?, where M is Al, Si, V, Mn, Fe, Co, Cu, Nb, Ag, or Pd, 0.1 = a = 1.4, 0.1 = b if, 3, 0.25 = c = 1.95, 0.1 = d = 1.4 a + b + c + d = 3 and 0 = x = 0.2. An alloy that have the formula ZrMo¿Nie where d = 0.1 to 1.2 and e = 1.1 to 2.5. An alloy having the formula Ti1_? Zr? Mn2_ zCr Vz where 0.05 s x s 0.4, 0 s and s l.O and O < z s 0.4. An alloy having the formula LnM5 wherein Ln is at least one lanthanide metal and M is at least one metal selected from the group consisting of Ni and Co. An alloy comprising at least one transition metal forming 40-75% by weight of the chosen alloy of groups II, IV and V of the Periodic System, and at least one additional metal, forming the rest of the alloy, with the last transitional metal, this additional metal chosen from the group consisting of Ni, Cu, Ag, Fe, and Cr-Ni steel. An alloy comprising a main texture of the Mn-Ni system; and a plurality of compound phases wherein each compound phase is segregated into the main texture, and wherein the volume of each of the compound phases is less than about 10 μm3. Preferred formulations of the base alloy described in the present invention contain from 0.1 to 60 atomic percent Ti, from 0.1 to 40 atomic percent Zr, from 0 to 60 atomic percent b, from 0.1 to 57 percent Atomic atom of Ni and from 0 to 56 atomic percent of Cr. The highly preferred formulations of this base alloy contain from 0.1 to 60 atomic percent of Ti, from 0.1 to 40 atomic percent of Zr, from 0.1 to 60 percent atomic of b, from 0.1 to 57 atomic percent of Ni and from 0 to 56 atomic percent of Cr.

In general, the alloys of the present invention comprise negative electrodes for metal hydride cells exhibiting an extremely high storage capacity and other significant quantitative improvements in their performance characteristics compared to the cells of the prior art. Surprisingly, the embodiments of the present invention show an improvement in most, if not all, of their operating characteristics, and thus can be considered cells of universal application. In accordance with the present invention, it has been found that the preferred alloys of the present invention described above in the Brief Description of the Invention can be further classified as having a disturbed microstructure, wherein the hydrogen in a particular phase is not easily discharged anymore. that through a low surface area or through an oxide of limited property or catalytic property. Specific examples of the alloys of the present invention are set forth in Table 2, below.

The effects of the addition of Mn can be seen in negative electrode materials of the present invention, wherein the Base Alloy is modified by 12 to 17 atomic percent Mn. In addition, the effects of Mn can also be observed when the base alloy is modified by one of the following combinations: (i) from 6.5 to 7.5 atomic percent of Co, from 13 to 17 atomic percent of Mn and from 0.5 to 2.5 percent-Atomic Fe; (ii) from 5.5 to 6.5 atomic percent of Co, 13.5 to 14.5 atomic percent of Mn, 1.5 to 2.5 atomic percent of Al and 0.25 to 1.0 atomic percent of Fe; (iii) from 3.5 to 5.5 percent Co atom, from 14.5 to 15.5 atomic percent of Mn, from 0.5 to 2.5 of Fe and from 0.2 to 1.0 of Zn; (iv) from 3.5 to 5 atomic percent of Co, from 14.5 to . 5 atomic percent of Mn, of 0.5 to 2.5 atomic percent of Fe and of 0.2 to 1.0 atomic percent of Sn. Co has become one of the most widely used elements in rechargeable batteries. Due to its limited supply, Co has become very expensive to use. Recently, the price of Co has increased 5%. It is estimated that the price of Co will increase as much as 30% by the year 2000. In response to these market forces, the inventors have successfully reduced the amount of Co needed in alloys of the present invention, so that the alloys optimized contain from 0-6 percent total atom of Co. In particular, alloy No 1, as set forth in Table 1, above, has been successfully used in prismatic electric vehicle batteries.

Although not intended to be bound by theory, it is believed that in the alloys of the present invention, Mn alters the microstructure in such a way that the precipitation of phases having hydrogen bonding resistances that are outside the scale of the electrochemical utility. One way in which Mn seems to achieve this is to increase the mutual solubility of the other elements within the primary phases during solidification. In addition, Mn functions in the electrochemically active surface oxide as a catalyst. For the multiple oxidation states of Mn it is believed that the electrochemical discharge reaction is catalyzed by increasing the porosity, conductivity and surface area of the active surface oxide film. This results in a significant increase in storage capacity (see Table 4). In addition to increasing capacity, Mn has other effects such as improved low temperature performance, low cell pressure, and a high life cycle. These effects are discussed in detail in U.S. Patent No. 5,277,999, the contents of which are incorporated herein by reference. Mn also acts as a replacement for Faith. Although not intended to be bound by theory, it is believed that when Mn is present without Faith, Mn helps the electrochemical discharge reaction at a low temperature by promoting bulk diffusion of hydrogen at low temperature and also catalyzing the reaction of hydrogen and hydroxyl ions on the surface of the alloy. Due to the low temperature properties of such alloys, it appears that the catalytic properties of Mn are emphasized when Fe is not present, or at least it is present only at low concentrations. Mn can also be substituted for Co. Although not intended to be bound by theory, it is believed that in the alloys described above, Mn alters the microstructure and acts as a catalyst in the electrochemically active surface oxide. The beneficial effects of Mn and Fe are also described in detail in U.S. Patent No.5,096,667, U.S. Patent No. 5,104,617, and United States Patent No. 5,238,756. The contents of all these references are incorporated herein by reference. It is noted in U.S. Patent No. 5,104,617 that it was widely believed that the inclusion of Fe in metal hydride hydrogen storage alloy materials could adversely affect electrochemical performance. This belief was due to the knowledge that Fe oxidizes easily and corrodes, particularly in the presence of an alkaline electrolyte. Oxidation reduces the performance of a metal hydride electrode in many forms, and Fe oxides in the prior art are known to adversely affect the positive electrode of nickel hydroxide, particularly with respect to charging efficiency and thus the capacity and life cycle. Many of the alloys of the present invention involve Mn. The effects of the addition of Mn to these alloys are generally described in U.S. Patent No. 5,096,667. The Mn alloy usually results in improved loading efficiency. Although not intended to be bound by theory, this effect seems to result from Mn's ability to improve alloy loading efficiency, it is added by improving oxidation resistance and oxygen recombination. It has been observed that oxygen gas was generated at the positive electrode of recombined nickel hydroxide on the surface of the metal hydride electrode. The recombination of oxygen is an oxidant especially aggressive of its environment, even compared to the alkaline electrolyte. It is possible that the modifying elements of the base alloy of the present invention, particularly Mn and Fe and very particularly Co, either alone in combination with Mn and / or Al, for example, act to catalyze the reduction of oxygen, avoiding or thus reducing the oxidation of the surrounding elements in the metal hydride alloy. It is believed that this function of the modified alloys reduces or even eliminates the formation- and development of harmful surface oxide, thus providing a thinner and more stable surface. Although not intended to be bound by theory, it is believed that several additional factors may explain the unexpected behavior of Mn and Fe in the base alloys of the present invention: (1) The combination of Mn and excess Fe can affect the alloy in volume by inhibiting the volume diffusion rate of hydrogen within the metal through the formation of complex phase structures, thus effecting either the grain boundaries or affecting the equilibrium binding strength of the hydrogen within the metal. In other words, the temperature dependence of the hydrogen bonding resistance can be increased thereby reducing the available voltage and capacity available under the low temperature discharge. (2) It is believed that the combination of Mn and excess Fe can result in a lower electrode surface area for metallurgical reasons by increasing the ductility of the alloy and thus reducing the amount of surface area formation during the activation process . (3) It is believed that the combination of Mn and Fe excess for these alloys can inhibit the low temperature discharge through the alteration of the same oxide layer with respect to the conductivity, porosity, thickness and / or catalytic activity . The oxide layer is an important factor in the discharge reaction and promotes the reaction of hydrogen from the base alloy of the present invention and the hydroxyl ion of the electrolyte. It is believed that this reaction is promoted by a thin, conductive, porous oxide that has some catalytic activity. The combination of Mn and excess Fe does not appear to be a problem under ambient temperature discharge, but has shown a surprising tendency to retard the reaction at low temperature. The formation of a complex oxide can result in a change in the structure of the oxide such as the pore size distribution or porosity. Since the discharge reaction produces water on the metal hydride surface and within the same oxide, a small pore size can cause a low diffusion of K + ions and OH "from the volume of the electrolyte to the oxide." Under discharge at room temperature, where the polarization is almost completely ohmic to the discharge of the low temperature, where the Activation and concentration polarization components dominate the physical structure of the oxides with Fe and Mn compared to Mn alone can be substantially different.

Yet another possible explanation is that Mn and Fe have multivalent oxidation states. - It is considered that some elements within the oxide can actually change the oxidation state during the normal state of charge variation as a function of the rate of discharge and they can be both temperature, manufacturing, can depend compositionally. It is possible that these multiple oxidation states have different catalytic activities, as well as different densities that together affect the porosity of the oxides. A possible problem with a complex oxide that contains both Mn and an excess of Fe, may be that the Fe component retards Mn's ability to change the oxidation state if it is present in large quantities. The function of addition Sn to the alloy is doubled. First of all, a small addition of Sn aids the activation of the alloy as the electrodes of the NiMh battery are used. Although not intended to be bound by theory, this is due to the desirable corrosion during the initial heat treatment. The addition of Sn also has the desirable function of cost reduction, since the Sn-containing alloy allows the use of lower cost versions of Zirconium metal, such as Zirvcalloy. Through the foregoing discussion with respect to the oxide, it should be understood that the oxide also contains other components of the Base Alloy of the present invention, such as V, Ti, Zr, Ni, and / or Cr and other modifying elements. The discussion of a complex oxide of Mn and Fe is purely for brevity and one skilled in the art should not infer that the current mechanism can not be included in a different or more complex explanation involving such elements. The negative electrodes using the alloys of the present invention can be used in many types of hydrogen storage cells and batteries. These include flat cells having a negative electrode of substantially flat plate, a separator, and a positive electrode or electrode that is substantially flat and aligned to be in operative contact with the negative electrode; gelatinous roller type cells made by spirally winding a flat cell about an axis; and prismatic cells for use in electric vehicles, for example. The metal hydride cells of the present invention can use any suitable type of container and can be constructed, for example, of metal or plastic. A 30 weight percent aqueous solution of potassium hydroxide is a preferred electrolyte. In a particularly preferred embodiment, the alloys used in conjunction with the advanced spacer materials such as those described in US Pat. No. 5,330,861, produce improved performance over the alloys of the prior art for certain electrochemical applications. In addition to the improved technical performance discussed above, the alloy modification offers cost advantages of up to 30%. One of the dominant factors that affect the cost of the base alloy is the cost of the vanadium metal. In U.S. Patent No. 5,002,730 incorporated for reference, vanadium in the form of V-Ni or V-Fe offers significant cost advantages over pure vanadium. Such cost improvements can be increased in the base alloys of the present invention through the use of V-Fe. EXAMPLES Preparation of negative electrode materials. The alloy materials described in Table 2, above, and the comparison materials described in Table 3 were prepared and manufactured as described below in negative electrode materials. The specific alloys used are presented in the Tables of each specific Example. The numbering of the alloys is consistent through the application and refers to Table 2 or Table 3.

TABLE 3 COMPARISON MATERIALS C1. V "Ti1ßZr, aNi" Cr-Cot C3. V2 } Ti1ßZr "NiMFßt C5 V21Ti15Zr, 5Ni31CrßCoaFeß C6. V, 5Ti1sZr2lNi3, CraCoaFeß C7. V, aT¡ "Zr" Ni31CrßCoíFßß C8. VZ2Ti11ZrJ, Ni3ßF «7 C9. V1ßTitsZruN¡2ßCriCo7Mn, The alloys of Tables 2 and 3 were prepared by loading and mixing starting materials of component elements in a graphite crucible as described in U.S. Patent No. 5,002,730 to Fetcenko and 4,948,423 to Fetcenko, et al. The crucible and its contents were placed in a vacuum oven, which was evacuated and then pressurized with approximately one atmosphere of argon. The contents of the crucible were fused by induction at high frequency while heating, while under an argon atmosphere. The melting was performed at the temperature of about 1500 ° C until a uniform melting bath was obtained. At this time, the heating was completed and the -fusion bath was allowed to solidify under a template of inert atmosphere. The alloy material ingot was then reduced in size in a multi-step procedure. The first step involved a hydride / dehydration procedure substantially as described in U.S. Patent No. 4,983,756 to Fetcenko, et al., Entitled Hydride Reactor. Append your Hydrogen Comminution of Metal Hydride Hydrogen Storage Alloy Material, the description of which is incorporated for reference. In this first step, the alloy was reduced in size to less than 100 meshes. Subsequently, the material obtained from the hydriding / dehydrating process was further reduced in size by an impact grinding process in which the particles were tangentially and radially accelerated against an impact block. This process is described in U.S. Patent No. 4,915,898 entitled Method for the Con tinuous Fabrication of Comminuted Hydrogen Storage Alloy Nega tive Electrode Material, the description of which is incorporated specifically for reference. A fraction of the alloy material having a particle size of less than 200 mesh and a mass average particle size of about 400 mesh (38 microns) was recovered from the impact milling process and ligated to a wire mesh screen current collector. nickel by a process involving the arrangement of a layer of alloy material on the current collector and compaction of the powder and collector. The compaction was carried out under an inert atmosphere with two separate compaction steps, each at a pressure of approximately 16 tons per square centimeter. After compaction, the current collector and the powder adhered thereto were sintered in an atmosphere of about 2 atomic percent hydrogen, the remainder being argon to form the negative electrode materials. (In general, sintering may not be required in all applications.) The need for sintering depends, of course, on the total cell design and factors such as the state of charge equilibrium.These alloys and negative electrodes were activated using the treatment of alkaline chemical attack described in U.S. Patent No. 4,716,088, the description of which is incorporated specifically for reference.As a practical matter of some oxidation occurs during the fabrication of the electrode, and thus, exposing the powder of alloy or negative electrodes of the present invention to an alkaline solution to "chemically attack" or alter the nature of the surface oxides they form, a variety of beneficial results are produced, for example, it is believed that the chemical attack alters the condition of the surface of the alloy powder or negative electrode material formed in such a way that it is achieved an improved load efficiency even in the first load cycle; promotes the ionic diffusion required for the electrochemical discharge process; creates a gradient of oxidation state on the surface of the material; and it alters the oxide of the surface to produce a greater acceptance of load. As mentioned by Ogawa in Proceedings of the 1988 Power Sources Symposium, Chapter 26, Hydride Meets the ectrode for High Energy Density and Seal ed Ni ckel-Metal Hydride Ba ttery similar effects can be obtained by "chemical etching" the dust alloy and then forming a negative electrode from this chemically attacked powder. See also, JPA 05/021 059 and JPA 05/013 077. Cell Preparation Negative electrodes prepared with positive electrodes of nickel hydroxide were assembled in sealed "C" cells having a resealable ventilation, as described in FIG. U.S. Patent No. 4,822,377, using 30% KOH electrolyte. Example 1 The finished cells prepared as described above, using the alloys set forth in Table 3, below, were subjected to loading and unloading conditions and to the determined Energy Density (mAh / g). The data obtained from these tests are set forth in Table 4 below.

Example 2 Corrosion measurements were conducted using electrodes made from the alloys listed in Table 5. These electrodes were prepared by cutting a thin slice (thickness ~ mm) of an ingot of alloy material. A copper wire for electrical measurements was attached to one side of the slice using a silver epoxy cement. The electrode was mounted on epoxy resin, so that only the face on which the copper wire was joined was covered; the opposite side of the electrode was exposed. The exposed face was polished using a 0.3 micron aluminum oxide paste and its geometric area determined for corrosion measurements. The corrosion potentials (Ecorr) and corrosion currents (icorr) of these electrodes were measured using a EG &G PARC corrosion measuring instrument. The measurements were conducted in a 30% solution of KOH. The corrosion potential of each electrode was determined by measuring the open circuit potential against a reference electrode Hg / HgO approximately 20 minutes after the electrode was immersed in the solution. Corrosion currents were measured using the polarization resistance technique (linear polarization). This technique was carried out by applying a tracer with a controlled potential of 0.1 mV / sec on a scale of ± 20 mV with respect to E.

The resulting current is plotted linearly against the potential. The inclination of this potential current function Ecorr e-sl-a Resistance d-e Polarization (** R "_p) '. * R" _p was used together with the Tafel constant ß (assumed as O.lV/decada) to determine icorr using the formula R = ßAßc / (2.3 (icorr1 (ßA ßc> > > In view of the foregoing, it is obvious to those skilled in the art that the present invention identifies and encompasses a scale of alloy compositions, which, when incorporated as a negative electrode into metal hydride cells, result in batteries having improved performance characteristics. The drawings, discussions, descriptions and examples of this specification are merely illustrative of particular embodiments of the invention and do not claim limitations of its practice. The claims are presented below, including all equivalents defining the scope of the invention.

Claims (43)

1. CLAIMS 1. A disrupted electrochemical hydrogen storage alloy characterized by comprising: (Base Alloy) gCo ^ Mnj ^ Fe ^ Sng where the Base Alloy comprises from 0.1 to 60 by atomic percent of Ti, from 0.1 to 40 per atomic percent of Zr, from 0 to 60 atomic percent of b, from 0.1 to 57 atomic percent of Ni and from 0 to 56 atomic percent of Cr; b is from 0 to 7.5 atomic percent; c is from 13 to 17 atomic percent; d is from 0 to 3.5 atomic percent, e is from 0.2 to 1.0 atomic percent; and a + b + c + d + e = 100 atomic percent.
2. 2. The disrupted electrochemical hydrogen storage alloy, according to claim 1, characterized in that c ee of 13 to 17 atomic percent; b and d are equal to 0.
3. 3. The disrupted electrochemical hydrogen storage alloy, according to claim 1, characterized in that b is from 4.5 to 7.5 atomic percent; c is from 12 to 17 atomic percent; and d is from 0.5 to 5.5 atomic percent.
4. 4. The disrupted electrochemical hydrogen storage alloy, according to claim 1, characterized in that b is from 0.5 to 7.0 atomic percent; c is from 12.0 to 14.5 atomic percent; and d is from 0.5 to 2.5.
5. 5. The disrupted electrochemical hydrogen storage alloy, according to claim 2, characterized in that there is no functional amount of Cr present.
6. 6. The disrupted electrochemical hydrogen storage alloy, according to claim 2, characterized in that there is 0.5 to 7.5 atomic percent of Cr present.
7. 7. The disrupted electrochemical hydrogen storage alloy according to claim 2, characterized in that there is no functional amount of Co present.
8. The decontaminated electrochemical hydrogen storage alloy according to claim 1, characterized in that the alloy comprises a disrupted microstructure, wherein the hydrogen in a particular phase is not easily discharged either through a low surface area or through an oxide of limited porosity or catalytic property.
9. 9. The decontaminated electrochemical hydrogen storage alloy, according to claim 1, characterized in that the alloy has a composition selected from the group consisting of: V, T¡, ZrJ7NijaCrs n, _ V4T¡sZr2rN¡j7Co5Mn "FßjSn04 V5Ti9Zr.7NiMCosMn? «Vyp9ZríßNiMCo, n1lFß, Ti oZruNjMCoJCr5Mn? ß VsT¡92r-aN¡MCosMn1, FßJ VsT¡, Zr" Ni37CosMn, 5Fß, vyp, ZrjaN¡3aCo5Mn1sFe4 Ti ^ ZrjoN ^ COjCrjMn ^ Ti, jZrwNij4Co7Cr1 n, sFß, V7Ti, Zr34N¡MCoJMn, # Fßj V, T¡10Zr2lNÍ34Cr3CoßMn, 4Fß2 VlTi9ZrJín¡ "Cos n15Fßj V2T? 10Zrj, NiMCr3CoaMn1 FßjSn1 V0 2Ti10Zr2lNijaCosCr3 n1t V4T «, Zr2, NiJ7Co5Mn, 5Fe2Sn04 V0 4 V0 sT¡, 0ZrJßNÍ34CoßCr3Mn, 4Fß2Sn2 V4Ti, Zr27NÍ38CosMn, sFß2Sn04
10. 10. The decontaminated electrochemical hydrogen storage alloy, according to claim 1, characterized in that the alloy has the following composition: V5TigZr27Ni38CR5MN16
11. 11. An electrochemical hydrogen storage alloy having an alloy surface enriched with Ni at the oxide interface, wherein the alloy surface enriched with Ni comprises regions enriched with nickel with a diameter of 50-70 A distributed through of the rust interface.
12. 12. The electrochemical hydrogen storage alloy according to claim 11, characterized in that the Ni-enriched regions vary from about 2 to 300 A from region to region.
13. 13. The electrochemical hydrogen storage alloy according to claim 11, characterized in that the regions enriched with Ni vary from about 50 to 100 A region to region.
14. 14. The decontaminated electrochemical hydrogen storage alloy according to claim 1, characterized in that the alloy has an alloy surface enriched with Ni.
15. 15. Allocated electrochemical hydrogen storage alloy, according to claim 14, characterized in that the Ni-enriched alloy surface comprises regions enriched with nickel having a diameter of 50-70 A distributed through the oxide interface.
16. 16. The decontaminated electrochemical hydrogen storage alloy according to claim 15, characterized in that the regions enriched with Ni have a closeness of 2 to 300 A 'from region to region.
17. 17. The disrupted electrochemical hydrogen storage alloy according to claim 15, characterized in that the regions enriched with Ni have a proximity of 50 to 100 A from region to region.
18. 18. A method for forming an electrochemical hydrogen storage alloy having regions enriched with Ni at the oxide interface comprising the steps of: formulating an electrochemical hydrogen storage alloy containing components that are preferentially corroded during activation; and activating the alloy to produce regions enriched with Ni; wherein the regions enriched with Ni have a diameter of 50-70 A and are distributed through the oxide interface.
19. 19. The method for forming an electrochemical hydrogen storage alloy, according to claim 18, characterized in that the electrochemical hydrogen storage alloy is classified as a TiVZrNi type, modified with the type LaNi5, LaNi ?, mischmetal, or Mg-based alloy. The method for forming an electrochemical hydrogen storage alloy, according to claim 18, characterized in that the electrochemical hydrogen storage alloy is selected from the group consisting of: alloys represented by the formula ZrMnwV? M Niz, where M is Fe or Co, and w, x, y and z are molar ratios of the respective elements where 0.4 < w < 0.8, 0.1 < x < 0.3, 0 = y < 0.2, 1.0 < z 1.5 and 2.0 = w + x + y + z < 2.4; alloys corresponding substantially to the formula LaNi5, in which one of the components La or Ni is replaced by a metal M selected from groups la, II, III, IV and Va of the Periodic Table of the Elements other than lanthanides, in an atomic ratio which is greater than 0.1% and less than 25%; alloys that have the formula TiV2_? Ni ?, where x = 0.2 to 0.6. alloys that have the formula TiaZrbNicCrdM ?, where M is Al, Si, V, Mn, Fe, Co, Cu, Nb, Ag or Pd, 0.1 = a =
20. 1. 4, 0.1 s b s 1.3, 0.25 s c s 1.95, 0.1 s d s 1.4 a + b + c + d = 3 and 0 s x s 0.2; alloys that have the formula ZrMo¿Nie where d = 0.1 to 1.2 and e = 1.1 to 2.5; alloys having the formula Ti1_? Zr? Mn2_y_ zCr Vz where 0.05 = x = 0.4, 0 = y = 1.0 and O < z = Ó.4; alloys having the formula LnM5, wherein Ln is at least one lanthanide metal and M is at least one metal selected from the group consisting of Ni and Co; alloys comprising at least one transition metal forming 40-75% by weight of the alloys chosen from groups II, IV and V of the Periodic System, and at least one additional metal, forming the remainder of the storage alloy of electrochemical hydrogen, which forms an alloy with the last transition metal, this additional transition metal selected from the group consisting of Ni, Cu, Ag, Fe, and Cr-Ni steel; and alloys comprising a main texture of the Mn-Ni system; and a plurality of compound phases, wherein each compound phase is segregated into the main texture, and wherein the volume of each of the compound phases is less than about 10 μm3.
21. 21. The method for forming an electrochemical hydrogen storage alloy, according to claim 18, characterized in that the electrochemical hydrogen storage alloy is a disrupted electrochemical hydrogen storage alloy comprising: (Base Alloy) aC? JD ncFecjSne where the Base Alloy comprises from 0.1 to 60 atomic percent of Ti, from 0.1 to 40 atomic percent of Zr, from 0 to 60 atomic percent of b, from 0.1 to 57 atomic percent of Ni and 0 at 56 percent atomic Cr; b is from 0 to 7.5 atomic percent; c is from 13 to 17 atomic percent; d is from 0 to 3.5 atomic percent, e is from 0 to 1.5 atomic percent; and a + b + c + d + e = 100 atomic percent.
22. 22. A method for forming an electrochemical hydrogen storage alloy having regions enriched with Ni at the oxide interface comprising the steps of: formulating a first electrochemical hydrogen storage alloy; formulating a second alloy containing components that are preferably corroded during activation to leave the regions enriched with Ni; allow mechanically alloying formation of the first alloy and the second alloy; and activating the first and second alloys mechanically formed in alloy.
23. 23. The method for forming an electrochemical hydrogen storage alloy, according to claim 22, characterized in that the first electrochemical hydrogen storage alloy is classified as a type TiVZrNi, modified LaNi5, LaNi5, mischmetal, or alloy based on Mg.
24. 24. The method for forming an electrochemical hydrogen storage alloy, according to claim 22, characterized in that the electrochemical hydrogen storage alloy is selected from the group consisting of: alloys represented by the formula ZrMnwV? M Niz, wherein M is Fe or Co, and w, x, y and z are molar ratios of the respective elements where 0.4 = w = 0.8, 0.1 = x = 0.3, 0 = y = 0.2, 1.0 < z = 1.5 and 2.0 = w + x + y + z < 2.4; alloys corresponding substantially to the formula LaNi5, wherein one of the components La or Ni is replaced by a metal M selected from groups la, II, III, IV and Va of the Periodic Table of the Elements other than the lanthanides, in an atomic ratio which is greater than 0.-1% and less than 25%; alloys that have the formula TiV2_? Ni ?, where x = 0.2 to 0.6. alloys that have the formula TiaZrjDNicCr (jM ?, where M is Al, Si, V, Mn, Fe, Co, Cu, Nb, Ag, or Pd, 0.1 sas 1.4, 0.1 = bs 1.3, 0.25 = c = 1.95, 0.1 = d = 1.4 a + b + c + d = 3 and 0 <x = 0.2, alloys that have the formula ZrMo ^ Nie where d = 0.1 to 1.2 and e = 1.1 to 2.5, alloys that have the formula Ti1_? Zr? Mn2_v_ zCr Vz where 0.05 <x = 0.4, 0 = y = lO and O <z = 0.4; alloys having the formula LnM5, where Ln is at least one lanthanide metal and M is at least one metal selected from the group consisting of Ni and Co, alloys comprising at least one transition metal forming 40-75% by weight of the alloys chosen from groups II, IV and V of the Periodic System, and at least one metal additional, forming the remainder of the electrochemical hydrogen storage alloy, which forms an alloy with the last transition metal, this additional transition metal selected from the group consisting of Ni, Cu, Ag , Fe, and Cr-Ni steel; and alloys comprising a main texture of the Mn-Ni system; and a plurality of compound phases, wherein each compound phase is segregated into the main texture, and wherein the volume of each of the compound phases is less than about 10 μm3.
25. 25. The method for forming an electrochemical hydrogen storage alloy, according to claim 22, characterized in that the electrochemical hydrogen storage alloy is a disrupted electrochemical hydrogen storage alloy comprising: (Base Alloy) aCo DMncFecjSne where the Base Alloy comprises from 0.1 to 60 atomic percent of Ti, from 0.1 to 40 atomic percent of Zr, from 0 to 60 atomic percent of b, from 0.1 to 57 atomic percent of Ni and 0 at 56 percent atomic Cr; b is from 0 to 7.5 atomic percent; c is from 13 to 17 atomic percent; d is from 0 to 3.5 atomic percent, e is from 0.2 to 1.0 atomic percent; and a + b + c + d + e = 100 atomic percent.
26. 26. An electrochemical hydrogen storage cell comprising: a negative electrode composed of a deranged electrochemical alloy having the following composition: (Base Alloy) aC? J =) MncFe¿Sne wherein the Base Alloy comprises from 0.1 to 60 atomic percent of Ti, from 0.1 to 40 atomic percent of Zr, from 0 to 60 atomic percent of b, from 0.1 to 57 atomic percent of Ni and from 0 to 56 atomic percent of Cr; b is from 0 to 7.5 atomic percent; c is from 13 to 17 atomic percent; d is from 0 to 3.5 atomic percent, e is from 0.2 to 1.0 atomic percent; and a + b + c + d + e = 100 atomic percent.
27. 27. The electrochemical hydrogen storage cell, according to claim 26, characterized in that in the deranged electrochemical alloy: c is from 12.5 to 17 atomic percent; b and d are equal to 0.
28. 28. The electrochemical hydrogen storage cell, according to claim 26, characterized in that in the deranged electrochemical alloy b is from 4.5 to 7.5 atomic percent; c is from 12 to 17 atomic percent; and d is from 0.5 to 5.5 atomic percent.
29. 29. The electrochemical hydrogen storage cell according to claim 26, characterized in that the deranged electrochemical alloy b is 0.5 to 7.0 atomic percent; c is from 12.0 to 14.5 atomic percent; and d is from 0.5 to 2.5.
30. 30. The electrochemical hydrogen storage cell according to claim 27, characterized in that the deranged electrochemical alloy does not contain any functional amount of Cr.
31. 31. The electrochemical hydrogen storage cell, according to claim 27, characterized in that the deranged electrochemical alloy contains from 0.5 to 7.5 atomic percent of Cr.
32. 32. The electrochemical hydrogen storage cell, according to claim 27, characterized in that the deranged electrochemical alloy does not contain functional amount of Co.
33. 33. The electrochemical hydrogen storage cell, according to claim 26, characterized in that the deranged electrochemical alloy has a disrupted microstructure, wherein the hydrogen in a particular phase is not easily discharged through the low surface area or through an oxide of limited porosity or catalytic property.
34. 34. The electrochemical hydrogen storage cell according to claim 26, characterized in that the deranged electrochemical alloy has a composition selected from the group consisting of: V, T, Zr? 7N¡3, CrsMn, ß V4Ti9Zrí7Nij7CosMn1iFß3Sn04 V5Ti9Zr27Nij, CosMn "VjT? 9Zr2lNi, 7CoJMn, sFßjSn0, V5ti9Zr2íN¡j, CosMn" Fß, T?, 0ZrJinij, Co, Crs n1, VsT¡, Zr- 6N¡MCo5Mn1sFß2 Ti, 0ZrJ7Nij < C? JCr4Mn, 3F? I V5T ?, ZrMN¡j7Co, Mn, sF?, T¡, 2Zr2, N¡j4Co5CrsMn14 V5Ti9Zr26N¡3aCo5Mn1sFe4 T¡, 3Zrj0Nij4CosCr, Mn " Ti, 2Zr2íNij4Co7Cr1Mn, 5Fß, V7Ti9Zr24Ni36Co, n "Fß,, Ti, 0Zr" NÍ34Cr3CoßMn, 4Fß2?, 0ZrjaNij4Cr3Coí n, 4Fß2Sn1? Ti, 0Zr2lNijaCosCr3Mn1, V? Ti9Zr2ßN¡3íCo5Mn, 5Fß2Sn04 V05T¡, 0Zr2ßNij4CoßCr3Mn, 4Fß2Sn2 V4T¡9Zr27NiMCos n15Fe2Sn04
35. 35. The electrochemical hydrogen storage cell, according to claim 26, characterized in that the deranged electrochemical alloy has the following composition: V5TigZr27Ni38CR5MN16
36. 36. An electrochemical hydrogen storage alloy having regions enriched with Ni at the oxide interface characterized in that it comprises: a first electrochemical hydrogen storage alloy; a second alloy mechanically formed in alloy to the first electrochemical hydrogen storage alloy; wherein the second alloy contains components that are preferentially corroded during activation to leave regions enriched with Ni.
37. 37. The electrochemical hydrogen storage alloy, according to claim 36, characterized in that the first electrochemical hydrogen storage alloy is classified as a TiVZrNi type, LaNi? modified, LaNi ?, mischmetal, or Mg-based alloy.
38. 38. The electrochemical hydrogen storage alloy, according to claim 36, characterized in that the second alloy is selected from the group consisting of: alloys represented by the formula ZrMnwV? M ^ Jiz, where M is Fe or Co, and w , x, y and z are molar ratios of the respective elements where 0.4 sw * 0.8, 0.1 sxs 0.3, 0 sys 0.2, 1.0 szs 1.5 and 2.0 * w + x + y + zs 2.4; alloys corresponding substantially to the formula LaNi5, wherein one of the components La or Ni is replaced by a metal M selected from groups la, II, III, IV and Va of the Periodic Table of the Elements other than the lanthanides, in an atomic ratio which is greater than 0.1% and less than 25%; alloys that have the formula TiV2_? Ni ?, where x = 0.2 to 0.6. alloys having the formula TiaZrjDNicCr¿?, where M is Al, Si, V, Mn, Fe, Co, Cu, Nb, Ag, or Pd, 0.1 s to s 1.4, 0.1 < b < 1.3, 0.25 < c = 1.95, 0.1 = d = 1.4 a + b + c + d = 3 and 0 = x < 0.2; alloys that have the formula Zr odNie where d = 0.1 to 1.2 and e = 1.1 to 2.5; alloys having the formula Ti1_? Zr? Mn2_ zCr Vz where 0.05 s x s 0.4, 0 = y = 1.0 and 0 < z = 0.4; alloys having the formula LnM5, wherein Ln is at least one lanthanide metal and M is at least one metal selected from the group consisting of Ni and Co; alloys comprising at least one transition metal forming 40-75% by weight of the alloys chosen from groups II, IV and V of the Periodic System, and at least one additional metal, forming the remainder of the storage alloy of electrochemical hydrogen, which forms an alloy with the last transition metal, this additional transition metal selected from the group consisting of Ni, Cu, Ag, Fe, and Cr-Ni steel; and alloys comprising a main texture of the Mn-Ni system; and a plurality of compound phases, wherein each compound phase is segregated into the main texture, and wherein the volume of each of the compound phases is less than about 10 μm3.
39. 39. The method for forming an electrochemical hydrogen storage alloy, according to claim 36, characterized in that the first electrochemical hydrogen storage alloy is a disrupted electrochemical hydrogen storage alloy comprising: (Base Alloy) aC? ] DMncFe (jSne where the Base Alloy comprises from 0.1 to 60 atomic percent of Ti, from 0.1 to 40 atomic percent of Zr, from 0 to 60 atomic percent of b, from 0.1 to 57 atomic percent of Ni and from 0 to 56 atomic percent of Cr; b is from 0 to 7.5 atomic percent; c is from 13 to 17 atomic percent; d is from 0 to 3.5 atomic percent, e is from 0 to 1.0 atomic percent; and a + b + c + d + e = 100 atomic percent.
40. 40. A method for forming an electrochemical hydrogen storage alloy having regions enriched with Ni at the oxide interface comprising the steps of: formulating a first electrochemical hydrogen storage alloy; formulating a second alloy; mechanically alloying the first alloy and the second alloy mechanically, and activating the first and second alloys mechanically formed in alloy.
41. 41. The method for forming an electrochemical hydrogen storage alloy, according to claim 40, characterized in that the first electrochemical hydrogen storage alloy is classified as a type TiVZrNi, modified LaNi5 type, LaNi ?, mischmetal, or alloy Mg base.
42. 42. The method for forming an electrochemical hydrogen storage alloy, according to claim 40, characterized in that the first electrochemical hydrogen storage alloy is selected from the group consisting of: alloys represented by the formula ZrMnwV? MyNi2, wherein M is Fe or Co, and w, x, y and z are molar ratios of the respective elements where 0.4 sws 0.8, 0.1 sxs 0.3, 0 sys 0.2, 1.0 sz = 1.5 and 2.0 = w + x + y + z = 2.4; alloys corresponding substantially to the formula LaNi ^, wherein one of the components La or Ni is replaced by a metal M selected from groups la, II, III, IV and Va of the Periodic Table of the Elements other than lanthanides, in an atomic proportion which is greater than 0.1% and less than 25%; alloys that have the formula TiV2_? Ni ?, where x = 0.2 to 0.6. alloys having the formula TiaZr ^ Ni CrjM ?, where M is Al, Si, V, Mn, Fe, Co, Cu, Nb, Ag, or Pd, 0.1 = a = 1.4, 0.1 = b < 1.3, 0.25 < c < 1.95, 0.1 < d = 1.4 a + b + c + d = 3 and 0 = x = 0.2; alloys having the formula ZrMo ^ Ni where d = 0.1 to 1.2 and e = 1.1 to 2.5; alloys having the formula Ti-, Zr? Mn2_v_ zCryVz where 0.05 = x = 0.4, 0 = y = l.O and O < z = 0.4; alloys having the formula LnM5, wherein Ln is at least one lanthanide metal and M is at least one metal selected from the group consisting of Ni and Co; alloys comprising at least one transition metal forming 40-75% by weight of the alloys chosen from groups II, IV and V of the Periodic System, and at least one additional metal, forming the remainder of the storage alloy of electrochemical hydrogen, which forms an alloy with the last transition metal, this additional transition metal selected from the group consisting of Ni, Cu, Ag, Fe, and Cr-Ni steel; and alloys comprising a main texture of the Mn-Ni system; and a plurality of compound phases, wherein each compound phase is segregated into the main texture, and wherein the volume of each of the compound phases is less than about 10 μm3.
43. 43. The method for forming an electrochemical hydrogen storage alloy, according to claim 40, characterized in that the first electrochemical hydrogen storage alloy is a disrupted electrochemical hydrogen storage alloy comprising: (Base Alloy) gCo ^ Mn Fe ^ Sn where the Base Alloy comprises from 0.1 to 60 atomic percent of Ti, from 0.1 to 40 atomic percent of Zr, from 0 to 60 atomic percent of b, from 0.1 to 57 atomic percent of Ni and from 0 to 56 atomic percent of Cr; b is from 0 to 7.5 atomic percent; c is from 13 to 17 atomic percent; d is from 0 to 3.5 atomic percent, e is from O to 1.5 atomic percent; and a + b + c + d + e = 100 atomic percent. RESVMEN. PB A INVENTION A deranged electrochemical hydrogen storage alloy is disclosed comprising: (Base Alloy) aC? JDMncFe (jSne wherein the Base Alloy comprises from 0.1 to 60 atomic percent Ti, from 0.1 to 40 atomic percent of Zr, from 0 to 60 atomic percent of b, from 0.1 to 57 atomic percent of Ni and from 0 to 56 atomic percent of Cr; b is from 0 to 7.5 atomic percent; c is from 13 to 17 atomic percent; d is from 0 to 3.5 atomic percent, e is from 0 to 1.5 atomic percent; and a + b + c + d + e = 100 atomic percent.