JPH11339790A - Metal-oxide/hydrogen storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal-oxide/hydrogen storage battery improving electric activation of a hydrogen storage alloy and suppressing elution of the ingredient. SOLUTION: This storage battery is provided with a negative electrode 4 including hydrogen storage alloy particles the surfaces of which is provided with at least one metal element selected among Cr, Mo, W, Nb, Co, Ni, Pd and Pt, and in which oxide is contained in a Zr-V alloy represented by the general formula: (Zr1-x Mx )2-z (V1-y Ty ), (here, M is at least one element selected between Ti and Hf, T is at least one element selected among Fe, Nb, Mo, Mn, Co and Ni, and (x), (y) and (z) respectively meet the following expressions: 0<=x<=0.9, 0.01<=y<=0.9, 0<=z<=1).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a metal oxide / hydrogen storage battery.

[0002]

2. Description of the Related Art Nickel / cadmium storage batteries and metal oxide / hydrogen storage batteries are known as high capacity storage batteries. Among them, metal oxide / hydrogen storage batteries provided with a negative electrode containing a hydrogen storage alloy that absorbs and releases hydrogen are widely used in portable electronic devices and the like as small sealed storage batteries having excellent environmental compatibility.

In the above-mentioned metal oxide / hydrogen storage battery, hydrogen storage alloys which play an important role as a negative electrode active material are mainly MmNi ₅ -based (Mm; misch metal) or TiM
An n ₂ -based alloy is used.

However, in a metal oxide / hydrogen storage battery provided with a negative electrode containing a MmNi ₅ system (Mm; misch metal) or a TiMn ₂ system hydrogen storage alloy, the hydrogen storage capacity of the hydrogen storage alloy is limited. It was difficult to further increase the capacity.

[0005] From the above, V-Ti, TiF
e-based and Ti ₂ Ni-based hydrogen storage alloys have been developed.
However, although these hydrogen storage alloys are excellent in direct reactivity with hydrogen gas at high temperatures, they have poor reactivity with hydrogen at room temperature and have a problem that initial activation is difficult.

On the other hand, JP-A-60-234933 and JP-A-61-143544 disclose that an oxide is contained in a hydrogen storage alloy to facilitate initial activation.

[0007]

However, the oxygen-containing hydrogen storage alloy used in the inventions described in each of the above publications has improved direct reactivity with hydrogen gas, but has an electrochemically active property in an alkaline electrolyte. The reactivity is still poor, and the initial activation cannot be sufficiently improved.

An object of the present invention is to provide a metal oxide / hydrogen storage battery capable of improving the electrical activation of a hydrogen storage alloy and suppressing the elution of its components.

[0009]

According to the present invention, there is provided a metal oxide-hydrogen storage battery comprising a Zr compound represented by the following general formula (I):
-V-based alloys contain oxides with Cr, Mo, W,
A negative electrode containing hydrogen storage alloy particles in which at least one metal element selected from Nb, Co, Ni, Pd and Pt is disposed.

(Zr _1-x M _x ) _2-z (V _1-y T _y ) (I) where M is at least one element selected from Ti and Hf, and T is Fe, Nb, At least one element selected from Mo, Mn, Co and Ni, x, y and z are respectively 0 ≦ x ≦ 0.9, 0.01 ≦ y ≦ 0.9, 0 ≦
Indicates z ≦ 1.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A metal oxide / hydrogen storage battery (for example, a cylindrical nickel metal hydride storage battery) according to the present invention will be described below with reference to FIG.

An electrode group 5 formed by laminating a positive electrode 2, a separator 3, and a negative electrode 4 and winding them in a spiral shape is accommodated in a bottomed cylindrical container 1. The negative electrode 4 is arranged at the outermost periphery of the electrode group 5 and is in electrical contact with the container 1. The alkaline electrolyte is contained in the container 1.

A circular sealing plate 7 having a hole 6 in the center is arranged at the upper opening of the container 1. The ring-shaped insulating gasket 8 is provided between the periphery of the sealing plate 7 and the container 1.
The sealing plate 7 is air-tightly fixed to the container 1 via the gasket 8 by caulking to reduce the diameter of the upper opening inward. One end of the positive electrode lead 9 is connected to the positive electrode 2, and the other end is connected to the lower surface of the sealing plate 7. The positive electrode terminal 10 having a hat shape is attached on the sealing plate 7 so as to cover the hole 6.

A rubber safety valve 11 is disposed in a space surrounded by the sealing plate 7 and the positive electrode terminal 10 so as to close the hole 6. A circular holding plate 12 made of an insulating material having a hole in the center is arranged on the positive electrode terminal 10 such that a protrusion of the positive electrode terminal 10 projects from the hole of the holding plate 12. The outer tube 13 covers the periphery of the holding plate 12, the side surface of the container 1, and the periphery of the bottom of the container 1.

Next, the positive electrode 2, the negative electrode 4, the separator 3
And the electrolyte will be described.

1) Positive electrode 2 This positive electrode 2 contains a nickel compound as an active material.

Examples of the nickel compound include nickel hydroxide, nickel oxide and nickel oxide in which nickel hydroxide, zinc and cobalt are co-precipitated.
Particularly, nickel hydroxide in which zinc and cobalt are coprecipitated is preferable.

The positive electrode (paste type positive electrode) is prepared, for example, by kneading a nickel compound as an active material, a conductive material and a binder together with water to prepare a paste, filling the paste into a conductive core, and drying the paste. It is produced by performing pressure molding as required.

As the conductive material, for example, at least one selected from a cobalt compound and metallic cobalt is used. As the cobalt compound,
For example, cobalt hydroxide [Co (OH) ₂ ], cobalt monoxide (CoO), and the like can be given. In particular, it is preferable to use cobalt hydroxide, cobalt monoxide, or a mixture thereof as the conductive material.

Examples of the binder include hydrophobic polymers such as polytetrafluoroethylene, polyethylene, and polypropylene; cellulosic materials such as carboxymethylcellulose, methylcellulose and hydroxypropylmethylcellulose; acrylic esters such as sodium polyacrylate; Examples include hydrophilic polymers such as polyvinyl alcohol and polyethylene oxide; and rubber-based polymers such as latex.

Examples of the conductive core include a mesh-like, sponge-like, fiber-like, or felt-like porous metal body made of nickel, stainless steel, or nickel-plated metal.

2) Negative electrode 4 This negative electrode 4 is made of a Zr-V represented by the following general formula (I).
System alloy containing oxide, Cr, Mo, W, N
It contains hydrogen storage alloy particles in which at least one metal element selected from b, Co, Ni, Pd and Pt is arranged.

(Zr _1-x M _x ) _2-z (V _1-y T _y ) (I) where M is at least one element selected from Ti and Hf, and T is Fe, Nb, At least one element selected from Mo, Mn, Co and Ni, x, y and z are respectively 0 ≦ x ≦ 0.9, 0.01 ≦ y ≦ 0.9, 0 ≦
Indicates z ≦ 1.

In the general formula (I), Ti is particularly preferred among M, and Fe is particularly preferred among T.

In the general formula (I), x, y and z are respectively 0.3 ≦ x ≦ 0.7, 0.25 ≦ y ≦ 0.75, 0.
More preferably, 2 ≦ z ≦ 0.6.

In particular, Ni is preferable among the metal elements.

As the oxide, for example, La ₂ O ₃ ,
Nd ₂ O ₃ , Sm ₂ O ₃ , Eu ₂ O ₃ , Yb ₂ O ₃ , B
_At least one selected from ₂ O ₃ , Al ₂ O ₃ , and SiO ₂ can be used. Particularly, La ₂ O ₃ is preferable as the oxide.

It is preferable that the content of the oxide with respect to the Zr-V alloy is 1 to 20% by weight. If the content of the oxide is less than 1% by weight, it is difficult to increase the capacity. On the other hand, if the content of the oxide exceeds 20% by weight, the amount of the oxide may relatively increase and the hydrogen storage performance may decrease.

The oxide-containing hydrogen storage alloy preferably contains at least 5% by volume of an η-carbite type crystal phase as a second phase.

[0030] In the hydrogen storage alloy particles, it is preferable that the metal element is arranged at 2 to 50% by weight on the surface of the oxide-containing hydrogen storage alloy. When the amount of the metal element is less than 2% by weight, it becomes difficult to sufficiently improve the electrochemical characteristics by the metal element. On the other hand, when the amount of the metal element exceeds 50% by weight, the high-rate discharge characteristics of the storage battery including the negative electrode including the hydrogen storage alloy particles may be deteriorated. A more preferred amount of the metal element is 5 to 20% by weight.

The hydrogen storage alloy particles are produced, for example, by the following method.

(1) Hydrogen storage alloy particles are prepared by mechanically grinding the oxide-containing hydrogen storage alloy together with the metal element powder in a vacuum or inert gas atmosphere.

(2) Hydrogen storage alloy particles are prepared by plating the metal element on the surface of the oxide-containing hydrogen storage alloy.

(3) After crushing the oxide-containing hydrogen storage alloy with hydrogen, the metal element is vacuum-plated on the alloy powder without contacting with oxygen to produce hydrogen storage alloy particles.

Of the methods (1) to (3), the method (1) is particularly preferable from the viewpoint of operability.

The negative electrode (for example, a paste type negative electrode) has a structure in which a negative electrode paste containing the hydrogen storage alloy particles, a binder, and a conductive material is supported on a conductive core.

Examples of the binder include those similar to those used for the positive electrode 2. This binder is
0.5 to 6 with respect to 100 parts by weight of the hydrogen storage alloy powder
It is preferable to mix by weight.

As the conductive material, for example, carbon black such as acetylene black, Ketchan black (trade name, manufactured by Lion Aguso), furnace black, or graphite can be used. This conductive material is preferably blended in an amount of 5 parts by weight or less based on 100 parts by weight of the hydrogen storage alloy powder.

Examples of the conductive core include a two-dimensional structure such as a punched metal, an expanded metal, a perforated rigid plate, and a wire mesh, and a three-dimensional structure such as a foamed metal and a mesh metal sintered metal fiber. be able to.

3) Separator 3 This separator 3 is made of, for example, an olefin-based nonwoven fabric such as a nonwoven fabric made of polyethylene fiber, a nonwoven fabric made of ethylene-vinyl alcohol copolymer fiber, or a nonwoven fabric made of polypropylene fiber, or an olefin such as a nonwoven fabric made of polypropylene fiber. Examples thereof include nonwoven fabrics made of a nonwoven fabric made of a base fiber and hydrophilic functional groups, and nonwoven fabrics made of polyamide fibers such as nylon 6,6. In order to impart a hydrophilic functional group to the olefin fiber nonwoven fabric, for example, corona discharge treatment, sulfonation treatment, graft copolymerization, or application of a surfactant or a hydrophilic resin can be employed.

4) Alkaline Electrolyte As the alkaline electrolyte, for example, a mixed solution of sodium hydroxide (NaOH) and lithium hydroxide (LiOH),
A mixture of potassium hydroxide (KOH) and LiOH, KOH
And a mixed solution of LiOH and NaOH.

The metal oxide according to the present invention described above
The hydrogen storage battery is a Zr-V represented by the general formula (I).
System alloy containing oxides and Cr, Mo, W,
It has a structure including a negative electrode containing hydrogen storage alloy particles in which at least one metal element selected from Nb, Co, Ni, Pd and Pt is arranged.

When the specific metal element is present on the surface of the oxide-containing hydrogen storage alloy, the metal element becomes an electrochemically active site of the oxygen-containing hydrogen storage alloy. Therefore, the initial activity of the oxide-containing hydrogen storage alloy particles is improved, and it becomes possible to electrochemically extract the excellent high capacity hydrogen storage capacity. Further, elution of the alloy component can be prevented by reducing the contact area of the surface of the oxide-containing hydrogen storage alloy with the alkaline electrolyte.

Therefore, a metal oxide / water storage battery provided with a negative electrode containing the hydrogen storage alloy particles having the above characteristics has excellent high rate discharge characteristics, charge / discharge cycle characteristics, and performance stability during storage.

In particular, the content of the oxide with respect to the Zr-V alloy is specified to be 1 to 20% by weight, or the metal element disposed on the surface of the oxide-containing hydrogen storage alloy is 2 to 20% by weight.
By setting the content to 50% by weight, a metal oxide / water storage battery having more excellent high-rate discharge characteristics, charge-discharge cycle characteristics, and performance stability during storage can be obtained.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

(Examples 1-1 to 1-8) <Preparation of Paste Type Negative Electrode> The alloy composition was Zr _1.0 Ti _1.0
V _1.0 Fe _1.0 so that the Zr, mixed Ti, V, and each element of Fe, was added La ₂ O ₃ in the mixture was dissolved and cooled in an argon atmosphere using the arc melting furnace.
This ingot is mechanically pulverized and the average particle size is 100 μm.
The following oxide-containing hydrogen storage alloy particles were obtained. Then,
20% by weight of various metal elements shown in Table 1 below were added to the alloy particles, and mechanically pulverized and mixed in an argon atmosphere to obtain eight kinds of hydrogen-absorbing alloy particles containing a surface-modified oxide.

Next, 1 part by weight of polytetrafluoroethylene as a binder and 0.1 part by weight of sodium polyacrylate were added to 100 parts by weight of the hydrogen absorbing alloy particles containing each surface-modified oxide.
2 parts by weight and carboxymethyl cellulose (CMC)
0.2 parts by weight were added. Further, 1 part by weight of carbon black as a conductive powder was added together with 50 parts by weight of water, followed by kneading to prepare nine kinds of pastes.
Subsequently, after filling each paste into foamed nickel having a porosity of 95%, the paste was dried at 125 ° C., press-molded to a thickness of 0.3 mm, and further cut to a width of 40 mm and a length of 100 mm to obtain nine kinds of pastes. A paste type negative electrode was manufactured.

<Preparation of Paste-Type Positive Electrode> To a mixed powder composed of 90 parts by weight of nickel hydroxide powder and 10 parts by weight of cobalt monoxide powder, 1 part by weight of polytetrafluoroethylene and 0.2 part by weight of carboxymethyl cellulose were added. A paste was prepared by adding 60 parts by weight of pure water to these and kneading them. Subsequently, this paste was filled in foamed nickel, dried, and then press-molded to obtain a width of 40 mm, a length of 80 mm, and a thickness of 0.67 mm.
Was produced.

Next, a polypropylene fiber non-woven fabric was interposed between each of the negative electrode and the positive electrode, and spirally wound to form eight kinds of electrode groups. After each such electrode group is accommodated in a bottomed cylindrical container, an electrolytic solution comprising a potassium hydroxide aqueous solution having a specific gravity of 1.31 is injected into the container, and the container is sealed and the like, as shown in FIG. 1 described above. AA size cylindrical nickel-metal hydride storage battery (capacity: 1200 mA)
h) was assembled.

Comparative Example 1 Example 1 was repeated except that the oxide-containing hydrogen storage alloy particles before surface modification with a metal element were used.
A paste similar to that of Example No. 1 was prepared, and this paste was filled in foamed nickel, dried, and press-molded to produce a paste-type negative electrode. Example 1 was repeated except that this paste type negative electrode was used.
An AA-size cylindrical nickel-metal hydride storage battery (capacity: 1200 mAh) having the structure shown in FIG.

The obtained storage batteries of Examples 1-1 to 1-8 and Comparative Example 1 were charged at 25 ° C. for 15 hours at a rate of 10 hours, and discharged at 25 ° C. to a final voltage of 1.0 V at a rate of 5 hours. A cycle test in which charge and discharge were repeated under the conditions was performed to examine initial activity and cycle characteristics. The initial activity was determined from the ratio of the first cycle discharge capacity to the maximum discharge capacity. The cycle characteristics were determined based on the number of cycles until the capacity of the storage battery of Comparative Example 1 reached 80%, and the ratio of the number of cycles until the capacity of each storage battery reached 80% to the reference cycle number.

Further, the storage batteries of Examples 1-1 to 1-8 and Comparative Example 1 were charged at 25 ° C. at a rate of 10 hours.
The high-rate discharge characteristics were determined from the ratio of the maximum discharge capacity obtained by cycling to a final voltage of 1.0 V at a rate of 10 hours at 25 ° C. and the maximum discharge capacity of the cycle test.

The results are shown in Table 1 below. The oxide-containing hydrogen storage alloy was pulverized, and the volume fraction of the η-carbite type crystal phase calculated from the diffraction peak intensity of the η-carbite type crystal phase by X-ray diffraction measurement is shown in Table 1.

[0055]

[Table 1]

As is apparent from Table 1, Cr,
The storage batteries of Examples 1-1 to 1-8 each including the negative electrode including the oxide-containing hydrogen storage alloy particles modified by disposing Mo, W, Nb, Co, Ni, Pd, and Pt had no surface. It can be seen that the initial activity, high-rate discharge characteristics, and cycle characteristics are superior to the storage battery of Comparative Example 1 including the negative electrode including the modified oxide-containing hydrogen storage alloy particles.

In particular, the storage batteries of Examples 1-4 provided with the negative electrode containing the oxide-containing hydrogen storage alloy particles modified by disposing Nb as a metal element have improved initial activity. The storage batteries of Examples 1-5 to 1-8 provided with the negative electrode including the oxide-containing hydrogen storage alloy particles modified by distributing Co, Ni, Pd, and Pt as metal elements have improved high-rate discharge characteristics. Is done. The storage batteries of Examples 1-1 to 1-3 provided with the negative electrode containing the oxide-containing hydrogen storage alloy particles modified by disposing Cr, Mo, and W as the metal elements have initial activity and high-rate discharge characteristics. Although slightly inferior, the cycle characteristics are improved.

Examples 2-1 to 2-31 La as oxide-containing hydrogen storage alloy particles before surface modification with a metal element
₂ O ₃ instead of the Ce ₂ O _3, Pr ₂ O _3, Nd
₂ O ₃ , Sm ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O ₃ , Tb ₂
O ₃ , Dy ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ , Tm ₂ O
₃ , Yb ₂ O ₃ , Lu ₂ O ₃ , Y ₂ O ₃ . Sc ₂ O ₃ ,
_{CaO, MgO, TiO 2, ZrO} 2, V 2 O 5, Cr
O, MnO, Fe ₂ O ₃ , CoO, NiO, CuO, A
Using g ₂ O, ZnO, B ₂ O ₃ , Al ₂ O ₃ , and SiO ₂ , these particles were surface-modified with Ni in the same manner as in Example 1-6. The resulting pastes were prepared, and these pastes were filled in nickel foam, dried, and press-molded to produce paste-type negative electrodes.
An AA-size cylindrical nickel-metal hydride battery (capacity: 1200 mAh) having the structure shown in FIG. 1 described above was assembled in the same manner as in Example 1-1 except that these paste-type negative electrodes were used.

With respect to the obtained storage batteries of Examples 2-1 to 2-31, initial activity, high-rate discharge characteristics and cycle characteristics were examined in the same manner as in Example 1-1. The results are shown in Tables 2 to 4 below. Tables 2 to 4 show the volume fraction of the η-carbite type crystal phase in the oxide-containing hydrogen storage alloy.
Table 1 below also shows Example 1-6 described above.

[0060]

[Table 2]

[0061]

[Table 3]

[0062]

[Table 4]

As is apparent from Tables 2 to 4, La ₂
Examples 2-1 to 2-1 provided with a negative electrode containing surface-modified oxide-containing hydrogen storage alloy particles containing another oxide instead of O _3.
It can be seen that the storage battery of 2-31 has excellent initial activity, high-rate discharge characteristics, and cycle characteristics.

In particular, among the added oxides, La ₂ O ₃ , Nd
₂ O ₃ , Sm ₂ O ₃ , Yb ₂ O ₃ , B ₂ O ₃ , Al ₂ O
_{3 It} can be seen that SiO ₂ exhibits excellent initial activity and cycle characteristics.

Further, it can be seen that the amount of the η-carbite type crystal phase in the oxide-containing hydrogen storage alloy changes depending on the added oxide.

(Examples 3-1 to 3-4) As oxide-containing hydrogen storage alloy particles before surface modification with a metal element, La _{2 was used.}
O ₃ 1%, 10%, 20%, 25% by weight
A paste containing surface-modified oxide-containing hydrogen storage alloy particles obtained by surface-modifying these particles with Ni in the same manner as in Example 1-6 was prepared, and these pastes were filled in foamed nickel. Drying and press molding were performed to produce a paste type negative electrode. Other than using these paste-type negative electrodes,
AA-size cylindrical nickel-metal hydride storage battery (capacity 1200) having the structure shown in FIG.
mAh).

Comparative Example 2 Hydrogen storage alloy particles not containing La ₂ O ₃ before surface modification with a metal element were used, and the particles were surface-modified with Ni in the same manner as in Example 1-6. A paste containing the surface-modified oxide-containing hydrogen storage alloy particles was prepared, and the paste was filled in foamed nickel, dried, and press-molded to produce a paste-type negative electrode. An AA-size cylindrical nickel-metal hydride battery (capacity: 1200 mAh) having the structure shown in FIG. 1 described above was assembled in the same manner as in Example 1-1 except that this paste-type negative electrode was used.

With respect to the obtained storage batteries of Examples 3-1 to 3-4, initial activity, high-rate discharge characteristics and cycle characteristics were examined in the same manner as in Example 1-1. The results are shown in Table 5 below.
Shown in Table 5 shows the volume fraction of the η-carbite type crystal phase in the oxide-containing hydrogen storage alloy. Table 1 below also shows Example 1-6 described above.

[0069]

[Table 5]

As is apparent from Table 5, the storage batteries of Examples 3-1 to 3-4 and 1-6 provided with the negative electrode containing the surface-modified oxide-containing hydrogen storage alloy particles containing a predetermined amount of La ₂ O _3. It can be seen that all of the batteries had excellent initial activity, high-rate discharge characteristics, and cycle characteristics as compared with the storage battery of Comparative Example 2 including the negative electrode containing the surface-modified hydrogen storage alloy particles without La ₂ O ₃ added. This is considered to be due to the fact that the η-carbite type crystal phase in the oxide-containing hydrogen storage alloy is generated as the second phase by the addition of the oxide.

However, if the added amount of the oxide is too large, the cycle characteristics tend to deteriorate. This is considered to be due to the fact that the volume of the oxide phase such as ZrO ₂ in addition to the η-carbide type crystal phase increases and the alloy dose per volume relatively decreases. Therefore, it is preferable that the amount of the oxide added is 1 to 20% by weight.

(Examples 4-1 to 4-3) 20% by weight of Ni having an average particle size of 5 μm was added to the same oxide-containing hydrogen storage alloy particles as in Example 1-1, and the mixture was ground and mixed in a mortar. Thus, hydrogen-absorbing alloy particles containing a surface-modified oxide were produced.

An electroless Ni-plated film was coated on the same oxide-containing hydrogen storage alloy particles as in Example 1-1 by 20% in terms of Ni.
The particles were coated so as to obtain a weight percentage of the surface-modified oxide-containing hydrogen storage alloy particles.

Further, an ingot of the same oxide-containing hydrogen storage alloy as in Example 1-1 was pulverized with hydrogen and vacuum-deposited while maintaining a vacuum so that Ni was reduced to 20% by weight in terms of Ni to improve the surface. Hydrogen storage alloy particles containing porous oxides were prepared.

Except for using the obtained three kinds of surface-modified oxide-containing hydrogen storage alloy particles, pastes similar to those in Example 1-1 were prepared, and these pastes were filled in foamed nickel.
Drying and press molding were performed to produce a paste type negative electrode. An AA-size cylindrical nickel-metal hydride battery (capacity: 1200 mAh) having the structure shown in FIG. 1 described above was assembled in the same manner as in Example 1-1 except that these paste-type negative electrodes were used.

With respect to the obtained storage batteries of Examples 4-1 to 4-3, initial activity, high-rate discharge characteristics and cycle characteristics were examined in the same manner as in Example 1-1. The results are shown in Table 5 below.
Shown in Table 6 shows the volume fraction of the η-carbite type crystal phase in the oxide-containing hydrogen storage alloy. Table 6 below also shows Comparative Example 1 and Example 1-6 described above.

[0077]

[Table 6]

As is clear from Table 6, the storage batteries of Examples 4-1 to 4-3 and 1-6 provided with negative electrodes containing hydrogen-absorbing alloy particles containing a surface-modified oxide with a metal element such as Ni were It can be seen that all of the initial activity, the high-rate discharge characteristics, and the cycle characteristics are superior to those of the storage battery of Comparative Example 1 including the negative electrode containing the hydrogen-oxide storage alloy particles whose surface has not been modified.

In particular, the rechargeable batteries of Examples 1-6, 4-2, and 4-3 provided with a negative electrode containing an oxide-containing hydrogen-absorbing alloy obtained by performing surface modification by mechanical pulverization, electroless plating, and vacuum deposition are as follows: The initial activity, the high rate discharge characteristics and the cycle characteristics are all superior to those of the storage battery of Example 4-1 including the negative electrode containing the oxide hydrogen storage alloy particles obtained by simple surface modification. Recognize.

(Examples 5-1 to 5-7) Ni was added to the same oxide-containing hydrogen storage alloy as in Example 1-1 at a ratio shown in Table 6 below, followed by mechanical pulverization in an argon atmosphere. ,
A paste was prepared in the same manner as in Example 1-1, except that seven kinds of surface-modified oxide-containing hydrogen storage alloy particles obtained by mixing were used. These pastes were filled in foamed nickel, dried, and press-molded to produce a paste-type negative electrode. Example 1 was repeated except that these paste type negative electrodes were used.
An AA-size cylindrical nickel-metal hydride storage battery (capacity: 1200 mAh) having the structure shown in FIG.

The obtained storage batteries of Examples 5-1 to 5-7 were examined for initial activity, high-rate discharge characteristics and cycle characteristics in the same manner as in Example 1-1. The results are shown in Table 5 below.
Shown in Table 7 shows the volume fraction of the η-carbite type crystal phase in the oxide-containing hydrogen storage alloy. Table 1 below also shows Example 1-6 described above.

[0082]

[Table 7]

As is clear from Table 7, Examples 5-2 to 5-2 provided with the negative electrode containing the surface-modified oxide-containing hydrogen storage alloy particles in which the amount of Ni to be surface-modified was 2 to 50% by weight.
It can be seen that the storage batteries Nos. 6 and 1-6 are particularly excellent in initial activity, high-rate discharge characteristics and cycle characteristics.

[0084]

As described above, according to the present invention, it is possible to improve the electrical activation of the hydrogen storage alloy and to suppress the elution of its components, and to achieve the initial activity, high rate discharge characteristics and cycle characteristics. And a metal oxide / hydrogen storage battery excellent in the above.

[Brief description of the drawings]

FIG. 1 is a perspective view of a nickel-metal hydride storage battery that is an example of an alkaline storage battery according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Container, 2 ... Positive electrode, 3 ... Separator, 4 ... Negative electrode, 5 ... Electrode group, 7 ... Sealing plate.

Claims (8)

[Claims] 1. Zr-V represented by the following general formula (I)
System alloy containing oxide, Cr, Mo, W, N
A metal oxide / hydrogen storage battery comprising a negative electrode containing hydrogen storage alloy particles in which at least one metal element selected from b, Co, Ni, Pd and Pt is arranged. (Zr _1-x M _x ) _2-z (V _1-y T _y ) (I) where M is at least one element selected from Ti and Hf, and T is Fe, Nb, Mo, Mn. , Co and Ni, x, y and z are respectively 0 ≦ x ≦ 0.9, 0.01 ≦ y ≦ 0.9, 0 ≦
Indicates z ≦ 1. 2. The metal oxide / hydrogen storage battery according to claim 1, wherein the oxide-containing hydrogen storage alloy contains an η carbide type crystal phase. 3. The method according to claim 1, wherein the oxide is La ₂ O ₃ , Nd.
₂ O ₃ , Sm ₂ O ₃ , Eu ₂ O ₃ , Yb ₂ O ₃ , B ₂ O
_3. The metal oxide-hydrogen storage battery according to claim 1, wherein the storage battery is at least one selected from the group consisting of ₃ , Al ₂ O ₃ , and SiO ₂ . 4. The metal oxide-hydrogen storage battery according to claim 1, wherein the content of the oxide with respect to the Zr—V-based alloy is 1 to 20% by weight. 5. The hydrogen storage alloy particles are produced by mechanically pulverizing the oxide-containing hydrogen storage alloy together with the metal element powder in a vacuum or an inert gas atmosphere. Item 5. A metal oxide-hydrogen storage battery according to any one of Items 1 to 4. 6. The metal oxide according to claim 1, wherein the hydrogen storage alloy particles are produced by plating the surface of the oxide-containing hydrogen storage alloy with the metal element. Hydrogen storage battery. 7. The hydrogen-absorbing alloy particles are produced by pulverizing the oxide-containing hydrogen-absorbing alloy with hydrogen and then vacuum plating the metal element on the alloy powder without contacting with oxygen. The metal oxide / hydrogen storage battery according to any one of claims 1 to 4, wherein: 8. The metal oxide according to claim 1, wherein the hydrogen-absorbing alloy particles have the surface of the oxide-containing hydrogen-absorbing alloy containing the metal element in an amount of 2 to 50% by weight. Goods and hydrogen storage batteries.