JPH09147855A - Hydrogen storage alloy for electrode having zr and ni as essential components - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide Laves phase hydrogen storage alloy containing Zr and Ni by which the cycle characteristic of a battery is improved so as to lengthen the life thereof when the alloy is used as the negative electrode of the battery. SOLUTION: One kind or two kinds or more of In, Bi, and Pb are contained in Laves phase hydrogen storage alloy expressed by a general formula, ZrαNiγMδ (where α, γ, δ are the atomic ratios of elements Zr, Ni, M respectively, α: 0.5 to 1.5, γ: 0.4 to 2.5, δ: 0.01 to 1.8, α+δ=1.2 to 3.7, one part of Zr can be substituted by one part of Ti, Hf, Ta, Y, Ca, Mg, La, Ce, Pr, Mm, Nb, Nd, Mo, Al, Si, and M is one kind or more of elements selected out of Fe, V, Mg, Ca, Hf, Ta, Nb, Cr, Mo, W, Mn, Co, Cu, Ag, Au, Zn, Cd, Al, Si, La, Ce, Mm, Pr, Nd, Tb.).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hydrogen storage alloy for electrodes, which contains Zr and Ni as essential components.
The present invention relates to a hydrogen storage alloy for electrodes, which contains Zr and Ni as essential components excellent in cycle characteristics when used as a negative electrode material of a secondary battery.

[0002]

2. Description of the Related Art Conventionally, hydrogen storage alloys have been used as negative electrode materials for alkaline storage batteries. This hydrogen storage alloy includes a Laves phase-based alloy mainly containing rare earth-based (La-Ni-based) and Zr-Ni. This rare earth type (La-Ni
As the system), those represented by the composition formula of AB ₅ such as LaNi ₅ and MmNi ₅ (Mm: misch metal) are known.

Further, as the Laves phase hydrogen storage alloy containing Zr--Ni, the general formula ZrαNiγMδ (where α, γ and δ are atomic ratios of Zr, Ni and M elements, α: 0.5 to 1.5, γ: 0.4 to 2.5, δ:
0.01 to 1.8 and γ + δ = 1.2 to 3.7, and a part of Zr is Ti, Hf, Ta, Y, Ca, Mg,
It can be substituted with one or more of La, Ce, Pr, Mm, Nb, Nd, Mo, Al and Si, where M is Fe,
V, Mg, Ca, Hf, Ta, Nb, Cr, Mo, W,
Mn, Co, Cu, Ag, Au, Zn, Cd, Al, S
1 selected from i, La, Ce, Mm, Pr, Nd, and Tb
Hydrogen storage alloys, which are represented by more than one element) and whose alloy phase substantially belongs to the Laves phase of an intermetallic compound, are known.

This Laves phase hydrogen storage alloy containing Zr--Ni has a higher electrochemical capacity than that of the rare earth hydrogen storage alloy used as an electrode when a battery is manufactured using this alloy as an electrode. 30% or more (Laves phase hydrogen storage alloy: 400 mAh / g, rare earth hydrogen storage alloy: 300 mAh / g), which is expected for high capacity batteries.

[0005]

However, this Laves phase type hydrogen storage alloy has a low cycle characteristic of repeating charging and discharging, and the cycle characteristic of a rare earth type hydrogen storage alloy (50
There was a drawback that it was significantly inferior to (0 times or more).
INDUSTRIAL APPLICABILITY The present invention, when used as an electrode material for an alkaline storage battery, improves the cycle characteristics of the battery and extends the life of Zr.
And a Laves phase hydrogen storage alloy containing Ni as an essential component.

[0006]

In order to achieve the above object, the present inventors have studied various aspects of the Laves phase type hydrogen storage alloy represented by the general formula ZrαNiγMδ, and found that the Laves phase system represented by ZrαNiγMδ The inventors have obtained the finding that the cycle characteristics are improved when the hydrogen storage alloy contains one kind or two or more kinds of In, Bi and Pb, so that the hydrogen storage alloy of the present invention was developed.

That is, the hydrogen storage alloy for electrodes, which has Zr and Ni as essential components of the alloy phase of the present invention, which substantially belongs to the Laves phase of the intermetallic compound, has the general formula ZrαNiγM
δ (where α, γ and δ are atomic ratios of Zr, Ni and M elements, respectively): α: 0.5 to 1.5, γ: 0.4 to 2.
5, δ: 0.01 to 1.8, a part of Zr is Ti,
Hf, Ta, Y, Ca, Mg, La, Ce, Pr, M
m, Nb, Nd, Mo, Al, a part of Si can be substituted, and M is Fe, V, Mg, Ca, Hf, Ta, N
b, Cr, Mo, W, Mn, Co, Cu, Ag, Au,
Zn, Cd, Al, Si, La, Ce, Mm, Pr, N
d, one or more elements selected from Tb), and the main alloy phase is a C14-type or C15-type Laves phase alloy containing 0.01, 1 or 2 or more of In, Bi and Pb. ˜1.0 wt% is contained.

[0008]

In the present invention, the hydrogen storage alloy containing Zr and Ni as essential components contains 0.01 to 1.0 wt% of one, two or more of In, Bi and Pb, and the cathode is the alkaline storage battery. Although the reason is unknown, there are cases where the cycle characteristic is improved and the cycle characteristic is 500 times or more.

Next, the content of In, Bi and Pb is set to 1
Explaining the reason why the species or two or more species are limited to 0.01 to 1.0 wt% atm%, the cycle characteristics are not improved when the content is less than 0.01% and more than 1.0%.

[0010]

Embodiments of the present invention will be described below. As a raw material, sponge Zr, sponge Ti, and metals V, Ni, Cr, Co, Fe, and Mn were mixed so as to have a predetermined composition, and were mixed in a high frequency induction furnace at 130
It melt | dissolved at 0 degreeC and manufactured the ingot. The composition of these ingots is as shown in Table 1.

[0011]

[Table 1]

After absorbing H _{2 in} these ingots, they were heated and evacuated to dehydrogenate, and then crushed to 7
The powder was 5 μm or less. These alloy powder and Ni net are integrally formed into a sheet having a thickness of 0.3 mm (operating pressure 10 t
on / cm ² ) and then heated and sintered at 900 ° C. for 30 minutes in an atmosphere of Ar / H ₂ = 99/1, and cut this into 40 mm × 105 mm to produce a hydrogen storage alloy electrode.

These hydrogen storage alloy electrodes are used as cathodes, and known sintered Ni electrodes (38 mm × 88 mm × 0.65) are used.
mm) as an anode and a separator made of a polyamide non-woven fabric having a thickness of 0.15 mm interposed therebetween and wound in a spiral shape, and a nickel-hydrogen battery was manufactured in a usual configuration except that this spiral electrode body was used. . As the electrolytic solution, 1.7 ml of an aqueous potassium hydroxide solution having a specific gravity of 1.29 was used.

After aging the nickel-hydrogen battery at 60 ° C. for 30 hours, the temperature is returned to room temperature to a constant temperature of 0.1 A.
After charging for 15 hours at 0.2 A, the battery was discharged at 0.2 A to 0.9 V. After repeating this twice to fully activate the battery,
A cycle of charging 105% of the initial capacity at 1 A and discharging to 0.9 V at 1 A is performed, and the battery capacity is 50% of the initial capacity.
The change in cycle life until the percentage was reached was investigated. The results are shown in Figures 1 and 2.

No. 1 of the embodiment of the present invention. The cycle life of the battery using the alloy of 5 to 14 as the negative electrode is In, Bi
No. of the comparative example containing no Pb and Pb. It is more than double that of using alloys 1 and 3. In addition, the cycle life of the battery using the alloy of the example of the present invention as the negative electrode was such that the In, Bi and Pb contents were smaller than those of the range of the present invention. Alloys 2 and 4 and Comparative Example Nos. With In, Bi and Pb exceeding the range of the present invention. It was proved that the effect of the present invention was remarkable, which was about 1.3 times longer than that using the alloys of 15 and 16.

In the above embodiment, the Laves phase hydrogen storage alloy Ti ₁₅ Zr ₂₁ V containing Zr and Ni as essential components is used.
₁₅ Ni ₂₉ Mn ₈ Cr ₅ Co ₆ Fe ₁ and Zr _32.2 V
_6.8 Ni _40.5 Cr _8.2 Mn _12.3 with In, Bi and Pb
0.01 to 1.0 wt% of one or more of the above, but any La hydrogen phase hydrogen storage alloy containing Zr and Ni as essential components can be used as In, Bi and 0.0% of one or more of Pb
By containing 1 to 1.0 wt% of this alloy, the cycle life of the battery using this alloy for the negative electrode can be extended. Further, the present invention is not limited to the embodiments in addition to the points described above, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

[0017]

The hydrogen storage alloy containing Zr and Ni as essential components according to the present invention contains 0.01 to 1.0 wt% of one, two or more of In, Bi and Pb, so that this hydrogen storage alloy can be used. It has an excellent effect that the cycle characteristics of the battery using the alloy for the negative electrode are significantly improved and the life is significantly extended.

[Brief description of the drawings]

1 is a Ti ₁₅ Zr ₂₁ V ₁₅ Ni ₂₉ Cr ₅ CO ₆ film of the present invention.
3 is a graph showing the relationship between the battery capacity and the cycle number of a battery using a Fe ₁ Mn ₈ hydrogen storage alloy.

FIG. 2 Zr _32.2 V _6.8 Ni _40.5 Cr _8.2 Mn of the present invention
₁ is a graph showing the relationship between the battery capacity and the cycle number of a battery using a _12.3 series hydrogen storage alloy.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takazumi Shimizu 37 North Gate, Takada, Ichinomiya City, Aichi Prefecture (72) Inventor, Takao Okochi 48-1 Yokata, Chita City, Aichi Prefecture Rinkaiso A204

Claims (1)

[Claims] 1. A general formula ZrαNiγMδ (where α,
γ and δ are atomic ratios of Zr, Ni, and M elements, respectively.
α: 0.5 to 1.5, γ: 0.4 to 2.5, δ: 0.01
˜1.8 and γ + δ = 1.2 to 3.7, Zr
Part of Ti, Hf, Ta, Y, Ca, Mg, La, C
e, Pr, Mm, Nb, Nd, Mo, Al and Si may be substituted, and M may be Fe, V, Mg,
Ca, Hf, Ta, Nb, Cr, Mo, W, Mn, C
o, Cu, Ag, Au, Zn, Cd, Al, Si, L
1 selected from a, Ce, Mm, Pr, Nd and Tb
In an alloy composed mainly of a C14 type or C15 type Laves phase represented by In,
One or more of Bi and Pb are added in an amount of 0.01 to 1.
A hydrogen storage alloy for an electrode, which contains Zr and Ni as essential components, characterized by containing 0 wt%.