JPH04143254A - Hydrogen occluding alloy electrode - Google Patents

Abstract

PURPOSE:To easily homogenize the alloy and to improve dry cell life and corrosion resistance against alkali electrolyte by adding specified amts. of V and elements which can easily form a solid solution with Ti-Fe alloy to an Ti-Fe alloy and alloying the mixture. CONSTITUTION:The hydrogen occluding alloy to be used as a negative electrode of metal-hydrogen alkali storage battery has the compsn. expressed by the formula. In this formula, A is one or more elements selected from Nb, Ta, Zr, W, Hf, Cr, Sn, and Ga, B is one or more elements selected from Co, Cr, Ir, Mn, Mo, Ni, Pt, Si, and Sn, and a, b, c, and d satisfy the relations 0.01<=a<=0.5, 0.01<=b<=0.5, 0.1<=c<=1.5, and 0.7<=d<=1.5. This alloy is plated with Cu, Ni, V, In, Zn, etc., to protect its surface. Or by coating thus alloy with hydrogen occluding alloy having a large amt. of residual hydrogen in a low hydrogenation pressure region or with metal oxide, corrosion resistance of the alloy can be improved and pulverization of the alloy accompanied with absorption and emission of hydrogen can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a hydrogen storage alloy electrode used as a negative electrode of a metal-hydrogen alkaline storage battery.

(b) Prior Art Storage batteries commonly used in the past include lead batteries and nickel-cadmium batteries. However, in recent years, with the potential to be lighter and have higher capacity than these batteries, metal oxides such as nickel hydroxide have been developed using hydrogen storage alloys that can reversibly absorb and release hydrogen as negative electrodes. Metal-hydrogen alkali storage batteries that use hydrogen as the positive electrode are attracting attention.

Generally, this type of hydrogen storage alloy electrode is produced as follows.゛■ As shown in Japanese Patent Publication No. 58-46827, a mixture of an alloy powder that absorbs hydrogen and an alloy powder that does not absorb hydrogen is sintered to produce a sintered porous body, which is used as a hydrogen-absorbing alloy electrode. how to.

■ As shown in JP-A-53-103541, a hydrogen-absorbing alloy powder, acetylene black, and an electrode support are bonded to each other using an electrolyte-resistant particulate binder to form a hydrogen-absorbing alloy electrode. how to.

And, as one of the hydrogen storage alloys used for the above electrode,
There is a Ti--Fe alloy disclosed in Japanese Patent Application Laid-open No. 176065/1983. This T i-F e alloy is viewed as promising because it can reversibly absorb and release hydrogen near room temperature and because its raw materials are relatively inexpensive.

Furthermore, in order to improve the characteristics of the Ti-Fe alloy, as shown in JP-A-62-184765, Ti
An alloy in which Zr, Ni, etc. are added to a -Fe alloy has been proposed.

(c) Problems to be solved by the invention However, even with the above alloy, it is difficult to electrochemically absorb and release hydrogen in an alkaline electrolyte, and the discharge capacity of the electrode is small, so it is difficult to put it into practical use. Needs improvement. In addition, conventional T i-F e
The alloy also had the problem that initial activation (chemical conversion treatment) was difficult compared to rare earth-Ni alloys.

The present invention takes the above problems into consideration and aims to provide a hydrogen storage alloy electrode that can eliminate the various drawbacks mentioned above.

(d) Means for Solving the Problems In order to achieve the above object, the present invention provides a hydrogen storage alloy electrode used as a negative electrode of a metal-hydrogen alkaline storage battery. It is characterized in that an alloy represented by formula (1) is used.

(T It-aA-)dF el-bB , V%+++
+・(1) [However, A is Nb, Ta, Zr,
One or more elements selected from the group consisting of W, Hf, Cr, Sn, and Ga; B is Co, Cr, Ir,
One or more elements selected from the group consisting of Mn, Mo5Ni, Pi, Si, and Sn, 0.01≦a≦0.5.0
．． 01≦b≦0.5.0.1≦c≦1.5.0.7≦d
It is within the range of ≦1.5. ] (e) Effect The base of the present invention is a Ti-Fe alloy, and this Ti
-Fe alloys are superior in that they are inexpensive and have a larger hydrogen storage capacity in solid-gas reactions than rare earth-Ni alloys.

However, this alloy has the problem that it is difficult to activate it at the initial stage of hydrogen absorption, and in particular, it is difficult to electrochemically absorb and release hydrogen in an alkaline electrolyte, resulting in an extremely low discharge capacity of the electrode.

However, as in the above structure, the elements such as V are replaced with Ti-
When added to Fe alloys, hydrogen absorption in alkaline electrolyte, initial activation of release, and electrochemical hydrogen absorption,
Since the discharge is facilitated, the discharge capacity of the electrode increases dramatically.

In addition, by adding elements that are easily dissolved in Ti and Fe (elements represented by A and B above) and alloying them, the resulting alloy becomes easier to homogenize and has improved corrosion resistance against alkaline electrolytes. , battery life will also be improved.

In addition, as an alloy manufacturing method, manufacturing methods other than normal arc melting method and high frequency melting method (e.g., liquid quenching method, sputtering method,
If a rapid cooling method such as a flash vapor deposition method is used, a non-equilibrium phase that is more homogeneous than that produced using an arc furnace, high frequency furnace, etc. can be obtained even if the stoichiometric ratio of the alloy components is significantly shifted. Therefore, the discharge capacity of an electrode using this alloy can be further increased.

In addition, the surface of the alloy of the present invention may be protected by plating one or more metals selected from Cu, Ni, V, In, Zn, or their compounds, or by a method selected from liquid quenching, sputtering, and flash vapor deposition. Using a type of method, the surface of the alloy of the present invention may be coated with a hydrogen storage alloy that has a higher amount of residual hydrogen in a low hydrogenation pressure range than the alloy of the present invention, or a metal oxide may be coated on the surface of the alloy of the present invention. , can be sintered and coated.

In this way, it is possible to improve the corrosion resistance of the alloy of the present invention against alkaline electrolytes and to suppress pulverization due to hydrogen absorption and release, thereby improving the durability of the electrode. Furthermore, if the surface of the present alloy is coated with a hydrogen storage alloy that has a large amount of residual hydrogen in a low hydrogen pressure region, even after the internal alloy (the present alloy) releases hydrogen, the residual hydrogen in the surface alloy will prevent oxidation of the internal alloy. In order to suppress
The durability of the internal alloy will be improved.

Furthermore, after crushing and powdering the alloy of the present invention (first component) and a different metal or oxide (second component), an alloy obtained by mixing and sintering them can be used directly, or in addition to this. If the surface of the mixed and sintered alloy is treated as described above, the first component, which has a large hydrogen storage capacity, and the second component, which prevents corrosion, are partially fused or alloyed. therefore,
In alloys consisting only of the first component, a decrease in hydrogen storage capacity is observed due to compositional changes to oxides and hydroxides.
In the mixed and sintered alloy, the composition of the first component is kept stable even when charging and discharging are repeated, so that a long-life electrode with little capacity loss can be obtained.

Furthermore, if the alloy of the present invention (the first component) and a dissimilar metal or alloy (the second component) are treated using a mechanical grinding method, the surface of the first component will be absorbed by the diffusion of the second component. covered by a layer. Therefore, the corrosion resistance against alkaline electrolytes is improved, and the composition of the first component is kept stable, so that an electrode with a long life and less capacity loss can be obtained.

(f) Example 1st Kanoman A first embodiment of the invention will be described below.

[Example 1] First, commercially available Ti (purity of 99% or more), commercially available Nb as A in the composition formula shown in formula (1) below, and commercially available Fe (
commercially available Co (purity 992 or more) as B in the composition formula shown in formula (1) below, and commercially available V (purity 99% or more) in an atomic ratio of 0.8:0.2. :0.9+
After weighing to give a ratio of 0.1:1, it is melted in an arc melting furnace in an argon atmosphere to obtain T ie, aN b
An alloy represented by e, F ea, *COo, , V was prepared.

(Ti+-, A,)aFe+-bBbVc...(1
) Next, after mechanically crushing this alloy to 50 μm or less, 80 wt Z of this powder was mixed with 10 wt χ of nickel powder as a conductive agent and 10 wt of fluororesin powder as a binder.
By adding χ and further mixing these, the above-mentioned fluorine street resin is made into fibers.

After this, after wrapping the above mixture in a nickel wire mesh,
A hydrogen storage alloy electrode was produced by pressure molding at a pressure of ton/c. Note that the amount of hydrogen storage alloy powder used in this electrode was 1.5 g.

After that, the hydrogen storage alloy electrode and the theoretical discharge capacity of 6.
A sealed nickel-metal hydride alkaline storage battery was fabricated by combining it with a known sintered nickel electrode of 00mAl1.

Note that a 30 wtZ potassium hydroxide aqueous solution is used as the alkaline electrolyte.

The battery thus produced is hereinafter referred to as (A1) battery.

[Examples 2 to 16 As the composition formula A shown in the above formula (1), commercially available purity 99%
Any of the above Ta, Zr, W, Hf, Cr, Sn, and Ga is used, and as B, commercially available N with a purity of 992 or higher is used.
i, Cr, Ir%MnSMo, Pt5Si,
A battery was produced in the same manner as in Example 1 above, except that alloys shown in Tables 1 (A) and (B) below were produced using either Sn, and a negative electrode was produced using this alloy.

The batteries produced in this way are described below as (A,) battery ~ (
It is called an At-) battery.

[Comparative Example] A battery was produced in the same manner as in Example 1 above, except that a negative electrode was produced using a TiFe alloy.

The battery thus produced is hereinafter referred to as the (X) battery.

[Experiment 1] A charge/discharge cycle test was conducted on the batteries (A,) to (Aug) of the present invention and the battery (X) of the comparative example, and the charging capacity after 100 cycles was investigated.The results are summarized in the following section. It is also shown in Table 1. The experimental conditions were 8 hour rate (0,125C
) after charging for 10 hours at a current of 5 hours (0,2C)
With a current of , the battery voltage is 1. The condition is to discharge until it reaches OV.

Table 1 (A) Table 1 (B) As shown in Table 1 (A) and (B), (A1) Battery ~ (A,,)! It is recognized that the discharge capacity of the battery is significantly larger than that of the (X)it battery.

In addition, the discharge capacity after 1000 cycles was also investigated.
For the (A1) battery to (A,,) battery, the capacity decreased by only 10 to 16%, and no major change was observed.

[Experiment 2] T j+-aN baF eo, *COs,,V,
The relationship between the amount of a and the discharge capacity of the alloy represented by was investigated, and the results are shown in FIG.

It is recognized that the discharge capacity increases in the range of 0.01≦a≦0.5, and especially in the range of 0.1≦a≦0.3 (
When a=0.2, the highest discharge capacity is 330mAll/g
), it is recognized that the discharge capacity is significantly increased.

Therefore, the value of a is preferably in the range of 0.01≦a≦0.5, particularly preferably in the range of 0.1≦a≦0.3.

[Experiment 3] The relationship between the amount of b in the alloy expressed as T101Nbo, Fe+-bcObV+ and the discharge capacity was investigated, and the results are shown in FIG. It is recognized that the discharge capacity increases in the range of 0.01≦b≦0.5, especially in the range of 0.01≦b≦0.5.
It is recognized that the discharge capacity is significantly large in the range of 05≦b≦0.2 (the maximum discharge capacity is 330 mAH/g when b=0.1). Therefore, the value of b is preferably in the range of 0.01≦b≦0.5,
In particular, the range of 0.05≦b≦0.2 is preferable.

[Experiment 4] The relationship between the amount of C in the alloy represented by T i,..., tFeo, 5Coo, +Vc and the discharge capacity was investigated, and the results are shown in FIG. It is recognized that the discharge capacity increases in the range of 0.1≦c≦1.5, especially in the range of 0.
．． It is recognized that the discharge capacity is significantly large in the range of 4≦c≦1.2 (when C=1, the discharge capacity is the highest, 330 mAl). Therefore, C
The value of c is preferably in the range of 0.1≦c≦1.5, particularly 0.
The range of 4≦c≦1.2 is preferable.

[Experiment 5] (T io, 5Nbo, *) aF eo, 5co
We investigated the relationship between the amount of d and the discharge capacity when the amount of d in the alloy represented by o, , v l was changed, and the results are shown in Figure 4 ((B,) in the figure). Shown below. 0.7≦d≦1
．． It is recognized that the discharge capacity increases in the range of 4, especially in the range of 0.9≦d≦1.35 (when d=1.2, the discharge capacity is the highest at 340 mAH/g). If so, it is recognized that the discharge capacity is significantly increased. Therefore, the value of d is preferably in the range of 0.7≦d≦1.4, particularly preferably in the range of 0.9≦d≦1.3.

In addition, as A shown in formula (1), in addition to those shown above, Ta,
Zr, W, Hf, Cr, Sn, Ga may be used, and B shown in formula (1) may include Ni, Cr,
It may be Ir, Mn, Mo, Pt, Si, or Sn.

Second Embodiment A second embodiment of the present invention will be described below. In this example, the case where the alloy is rapidly cooled will be mainly described.

[Example 1] This example is a case where a liquid quenching method is used as the quenching method.

First, using commercially available raw materials (purity 99z or higher) of Ti, Fe, Nb, Co, and V, the following (2) was carried out in an argon inert atmosphere arc melting furnace in the same manner as in Example 1 of the first example above.
A hydrogen storage alloy represented by the formula was created.

(Ti61Nbo, z) dFeo, *COo, +V
+ ” ” ” (2) The value of d is 0.6 to 1
．． It is varied within a range of 6. -7 Next, after crushing these alloys into small pieces of about 5 to 15 mm square, they were inserted into transparent quartz nozzles (nozzle hole: round hole 1.0 mm').
After replacing with high-purity argon gas (purity of 99.992 or higher), 3 kW of high-frequency power was applied to the high-frequency induction heating coil using a high-frequency power source to heat it. Next, after the alloy is melted, the inside of the quartz nozzle is pressurized with argon gas,
The molten metal of the alloy was spouted onto a copper roller (300 mm, width 40 mm) rotating at high speed (2000 r, p, m, ) in a latm atmosphere of argon gas (purity 99.99 Z or higher) and rapidly solidified. , a ribbon-shaped quenched hydrogen storage alloy was obtained.

A battery was produced in the same manner as in Example 1 of the first embodiment, except that a negative electrode was produced using the quenched hydrogen storage alloy thus produced.

The battery thus produced is hereinafter referred to as a pond (B,).

[Example 2] In this example, a sputtering method is used as the rapid cooling method. First, the above (
2) The alloy shown in the formula (the value of d is varied in the range of 0.6 to 1.6) was heated to a sputter target (4 inch
Using this sputtering target, a high-frequency magnetron sputtering device (under an argon gas atmosphere, under a pressure of I
A sputtered film of the above-mentioned alloy was formed on a nickel substrate using the following steps. At this time, the output of high frequency power is 500W (1), 5
6 MHz), and the sputtering time was 10 hours. Thereafter, the nickel substrate was taken out of the apparatus, and the sputtered film of the alloy adhering to the substrate was peeled off using a scraper (made of stainless steel) to obtain about 8 g of thin pieces of the hydrogen storage alloy. A battery was produced in the same manner as in Example 1 of the first embodiment, except that a negative electrode was produced using the quenched hydrogen storage alloy thus produced.

The battery thus produced is hereinafter referred to as a (B,) battery.

[Example 3] First, an alloy shown in formula (2) produced in the same manner as in Example 1 above (the value of d was varied in the range of 0.6 to 1.6) was rapidly cooled by flash vapor deposition. However, a battery was produced in the same manner as in Example 1 of the first embodiment, except that a negative electrode was produced using this quenched hydrogen storage alloy.

The battery thus produced is hereinafter referred to as a (B4) battery.

[Experiment] The relationship between the value of d in the battery (B,) and the discharge capacity of the hydrogen storage alloy electrode was investigated, and the results are shown in FIG.

As is clear from Figure 4, 0.7 for all batteries.
It is recognized that the discharge capacity exceeds 280 mAH/g in the range of ≦d≦1.5. Therefore, the value of d is preferably within the above range.

In addition, it is recognized that the hydrogen storage capacity of the batteries (B,) to (B,) is larger than that of the battery (B1). Furthermore, in the (B,) battery, a rapid capacity drop is observed when the value of Z exceeds 1.2, whereas in the (B,) battery ~ (B,) battery, the value of d is up to approximately 1.3. It is recognized that the discharge capacity has increased. Therefore, from the viewpoint of discharge capacity, it is preferable to subject the hydrogen storage alloy to rapid cooling treatment.

Furthermore, (B1) battery - (B,) battery is 100
The discharge capacity after 0 cycles was also examined, but no major change was observed, with the capacity only decreasing by 10 to 2°2.

Third Embodiment In this embodiment, a case where the surface of the alloy is coated with another metal or the like will be described in order to improve the durability of the alloy.

[Example 1] In Example 1, a plating method is used as a surface coating method for the alloy. As a mother alloy, Ti shown in Example 1 of the first example, 5N1)a, Jeo, 5coo, l
A copper plating layer of about 1 μm was formed on the surface of this alloy by wet electroless copper plating using an alloy powder of vl (100 mesh or less). A battery was produced in the same manner as in Example 1 of the first embodiment, except that a negative electrode was produced using the surface-coated hydrogen storage alloy.

The battery thus produced is hereinafter referred to as a (C1) battery.

[Examples 2 to 6] As plating metals, Ni, V, In, Zn, Nio,
m5-P o,. Batteries were produced in the same month as in Example 1 above, except that 1 was used in each case.

The batteries produced in this way are described below as (C2) batteries ~ (
C,) is called a pond.

[Example 7] Example 7 is a case where sputtering was used as a surface coating method for the alloy. Example 1 of the first example as a master alloy
A thin layer (approximately 1 μm) of ZrNi alloy, which has a higher amount of residual hydrogen at low hydraulic pressure than the above-mentioned mother alloy, is applied to the surface of the hydrogen-absorbing alloy powder (100 mesh or less) shown in
was formed by a normal sputtering method.

A battery was produced in the same manner as in Example 1 of the first embodiment, except that a negative electrode was produced using the surface-coated hydrogen storage alloy.

The battery thus produced is hereinafter referred to as a (C7) battery.

[Example 8] A battery was produced in the same manner as in Example 7, except that flash vapor deposition was used as the surface coating method for the alloy.

The battery thus produced is hereinafter referred to as a (C1) battery.

[Example 9] In Example 9, a method of coating the surface of the alloy by applying a metal oxide and then sintering was used. Powder of the hydrogen storage alloy shown in Example 1 of the first example was used as the mother alloy (
100 meshes or less), and N d = 0
A solution prepared by dispersing * in an organic solvent was applied to the surface of the mother alloy, and then sintered in a vacuum at 1000° C. for 3 hours. A battery was produced in the same manner as in Example 1 of the first embodiment, except that a negative electrode was produced using the surface-coated hydrogen storage alloy.

The battery thus produced is hereinafter referred to as a (C1) battery.

[Experiment 1] The batteries (C1) to (C9) of the present invention were subjected to a charge/discharge cycle test to examine the discharge capacity after 100 cycles, and the results are shown in Table 2 below.

Note that the experimental conditions are the same as those in Experiment 1 of the first example.

As is clear from Table 2 in Table 2 below, the (C0) to (C9) batteries are the (A,)! It is observed that the discharge capacity is slightly increased compared to the pond.

In addition, the charge capacity after 1000 cycles was also investigated for the batteries (C1) to (C9). As a result, it was confirmed that the decrease in capacity was only about 5 to 1 oz, and the durability was further improved than that of the battery (A,).

Fourth Example First, in the same manner as in Example 1 of the first example, Ti,
T+ as the first component using Nb, Fe, Co, V
6sNbo, Jeo, *COo, 1v1 alloy ingot was prepared and M m N i@ as the second component.
A Co alloy ingot is produced. Next, after the alloy ingots of the first component and the second component are crushed into 100 meshes or less (approximately 0.15 mm or less), both are mixed. The mixing ratio was 1:1 (first component: second component) by weight. Thereafter, this mixture was press-molded into a cylindrical shape (approximately 20 mm' x approximately 10 mm) at a pressure of approximately 30 kg/cm'', and the molded product was evacuated (below 10-'' Torr).
It was heat-treated in an electric furnace (temperature: about 1000°C) for about 8 hours and sintered. Thereafter, a battery was fabricated in the same manner as in Example 1 of the first example, except that a negative electrode was fabricated using the hydrogen storage alloy thus fabricated.

The battery thus produced is hereinafter referred to as a (Dl) battery.

[Comparative Example] Example 1 above except that the negative electrode was produced using a hydrogen storage alloy that was simply a mixture of the first component and the second component without sintering.
A battery produced in the same manner as above is hereinafter referred to as a (D2) battery.

[Experiment] A discharge cycle test was conducted on the (Dl) battery and (D,) battery of the present invention to examine the discharge capacity after 100 cycles, and the results are shown in Table 3.

Note that the experimental conditions are the same as those in Experiment 1 of the first example.

Table 3 As is clear from Table 3, it is recognized that the (Dl) battery has an even larger discharge capacity than the (D,) battery.

In addition, the discharge capacity of both batteries after 1000 cycles was also investigated. As a result, a capacity decrease of about 20χ was observed in (D,), but in the pond (D,), the capacity decreased by only about 1]χ, and from this point of view, (D,)! Ponds are better.

Further, when the surface coating shown in the third example was applied to the surface of the mixed sintered material, the decrease in capacity after 1000 cycles could be suppressed to 5 to 1 oz.

Therefore, it is desirable to use the mixed sintering method and surface coating in combination.

Fifth Example [Example 7] This example is a case where a mechanical grinding method is used as an alloy manufacturing method. Tlo aNbox as the first component produced in the same manner as in the fourth example above
Feo *COo, +V+ alloy powder 49g (100 mesh or less) and MmNixCo* powder 1g as the second component were loaded into a metal pot filled with Ar gas, and mechanical grinding was performed at room temperature. Ta.

The rotation speed of the pot was about 10 Or, p, m, and the treatment time was about 10 hours. By this mechanical grinding method, an alloy powder is produced in which the second components Mm and Ni are diffused into the first component powder surface layer. A battery was manufactured in the same manner as in Example 1 of the first example, except that the negative electrode was manufactured using such an alloy. The battery thus produced is hereinafter referred to as the (E) battery.

[Experiment] The discharge capacity of the battery (E) of the present invention was investigated, and the results are shown in Table 4 below.

Table 4 As is clear from Table 4, it is recognized that the battery (E) has a higher capacity than the battery (D,) of the fourth example.

In addition, the discharge capacity of both batteries after 1000 cycles was also investigated. As a result, it was found that the durability was excellent with only a decrease in the 20χ capacity.

Similar results were also obtained when a hydrogen storage alloy was produced using a mechanical alloying method.

(g) As described in detail, according to the present invention, hydrogen is easily absorbed and released electrochemically in an alkaline electrolyte, and the discharge capacity of the electrode is increased.

In addition, initial activation is easier than with conventional TiFe alloys. For these reasons, the battery characteristics can be significantly improved, such as having a high energy density.

[Brief explanation of drawings]

Figure 1 shows Ti+-aNbaFeo, sco. , l
A diagram showing the relationship between the value of a and the discharge capacity when the amount of a in the alloy represented by vl is changed. Figure 2 is Tie, @Nb
Figure 3 shows the relationship between the value of b and the discharge capacity when the amount of b in the alloy expressed as Je+4CObV+ is changed. tllb++ Jeo, *COo, A diagram showing the relationship between the value of C and discharge capacity when the amount of C in the alloy is changed, expressed as IvC. Figure 4 is (Ti,,5Nt)al)J
5 is a diagram showing the relationship between the value of d and the discharge capacity when the amount of d of the alloy represented by eo, 5cOa, and +V+ is changed. FIG. Figure 1 QOl 0.3 0.4 0.5 yi, -. NbaFe6. q Co01t V+4++=h+76
asi 5L Fig. 2 0001αO5Q+ 0.2
03 OAT! os Nbo2Fe1-1
．． Cob V+ (ν diagnosis + = h゛ke'bbs4 shift 3rd figure TiOβ Nb0.2 Feo, 9 C00, 1vC1] - Bei
〉+:b S bushie ecf) i J1 Fig. 4 (Tins NbcL2) d

Claims (1)

[Scope of Claims] [1] A hydrogen storage alloy electrode characterized in that an alloy represented by the following general formula (1) is used as a hydrogen storage alloy for use in the negative electrode of a metal-hydrogen alkaline storage battery. (Ti_1_-_aA_a)_dFe_1_-_bB_
bV_c...(1) However, A is Nb, Ta,
B is one or more elements selected from the group consisting of Zr, W, Hf, Cr, Sn, and Ga, and B is Co, Cr, Ir,
One or more elements selected from the group consisting of Mn, Mo, Ni, Pt, Si, Sn, and the range of a is 0.01
The range of ≦a≦0.5, b is 0.01≦b≦0.5, c
The range of is 0.1≦c≦1.5, and the range of d is 0.7≦a
≦1.5. [2] The hydrogen storage alloy electrode according to claim [1], wherein the alloy is an alloy in a non-equilibrium state. [3] The hydrogen storage alloy electrode according to claim 2, wherein the non-equilibrium alloy is manufactured using a rapid solidification method. [4] The hydrogen storage alloy electrode according to claim [3], wherein one of a liquid rapid cooling method, a sputtering method, and a flash vapor deposition method is used as the rapid solidification method. [5] Claim [3] wherein the non-equilibrium alloy is manufactured using one of mixed sintering, mechanical grinding, and mechanical alloying.
] Hydrogen storage alloy electrode described. [6] Claims [1], [2], [3], [2] characterized in that a corrosion prevention film is used on the surface of the alloy.
4] or the hydrogen storage alloy electrode described in [5]. [7] The hydrogen storage alloy electrode according to claim [6], wherein an oxide is used for the corrosion prevention film. [8] The corrosion prevention film may include Cu, Ni, V, In,
The hydrogen storage alloy electrode according to claim 6, characterized in that it is produced by plating with Zn or one of its compounds. [9] The hydrogen storage alloy electrode according to claim [6], wherein a hydrogen storage alloy having a higher amount of residual hydrogen than the alloy in a lower hydrogen pressure region is used as the corrosion prevention film. .