JPS61181063A - Hydrogen occulusion electrode - Google Patents

Abstract

PURPOSE:To improve the discharging capacity and the cycle characteristic by employing an crystal structure of CaCu5 where at least one element selected from specific metals is contained in Misch metal-cobalt alloy. CONSTITUTION:Crystal structure of CaCu5 where at least one element selected from Si, Ti V, Fe, Ni, Zn, Y, Zr, Nb, Mo, Hf, Ta and alkaline earth metal is contained in MmCo5 base alloy is employed in the negative pole. 80wt% of various hydrogen occulusion alloy powder, 10wt% of conducting material or acetylene black and 10wt% of binding agent or fluororesin powder are mixed uniformly through mixer while fluororesin is converted into fiber then the mixture is surrounded by nickel mesh and pressure molded. About 1.5g of alloy powder is employed for the hydrogen occulusion electrode. Consequently, the discharge capacity and the cycle characteristic can be improvd resulting in high performance storage battery.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a hydrogen storage 4Ta used as a negative electrode of an alkaline storage battery, and particularly relates to a hydrogen storage electrode improved to maintain high capacity over a period of time. .

(Conventional technology) Lead-acid batteries and Nilaglu-dominic batteries have traditionally been commonly used storage batteries, but in recent years, it has been discovered that the storage batteries are lighter and have a higher capacity than these batteries, so they are gradually becoming lower voltage.゛Using an electrode equipped with a Mizuki suction 7 or an i- that can be released in an inverted circle and releasing hydrogen, which is an active material of the negative electrode, as the negative electrode, * Generalized gold positive electrode materials such as hydroxide niggle etc. Quantitative metal-Mizuki alkaline reservoirs using a positive electrode as the positive electrode are attracting attention.

This building in general! - Hydrogen storage electrodes equipped with hydrogen storage alloys used in QL ponds are made of alloy powders that store water #1 and alloy powders that do not store hydrogen, as proposed in Japanese Patent Publication No. 58-46827. A method of producing a sintered porous body by sintering a mixture of the above and using it as a hydrogen storage electrode, or an alloy powder that stores hydrogen t- as reluctantly proposed in Japanese Patent Application Laid-open No. 53-103541-1. and acetylene black and a particulate adsorbent having T4 resistance such as an electrode insert are bonded to each other to form a hydrogen storage electrode. However, this hydrogen storage electrode equipped with MmCos has hydrogen absorption a
1 ton was small, and the cycle life due to charging and discharging was short, so it was not completely satisfactory.

1,=) Problems to be Solved by the Invention The present research aims to improve the life of a hydrogen storage electrode that has many water holes that can be stored and released, and has a long cycle life due to repeated charging and discharging.

2) Means for solving the interstitial temperature problem The hydrogen storage electrode of the present invention is based on MmCos, and the alloy contains Si%"ri%Vs Fes Ni, Zns Y
%Zr, NbsMo%Hf, Ca containing at least one element selected from Ta and alkaline earth metals
This uses a negative electrode with a Cu5 crystal structure.

(E) Function A hydrogen storage electrode comprising an alloy having a CaCu5 crystal structure based on MmCos and containing one of the above elements as a hydrogen storage material has an extended cycle life due to charging and discharging. Discharge capacity increases.

(f) Example Commercially available Mitsushi metal, cobalt and silicon were used as alh
y, ratio Mm:Co:5i=l:4.8:0.2 VC
The crystal structure is CaCu5 structure.
MmCOcaSiα2@rice was obtained, and the mixing, alloying, and pulverizing operations described above were performed to obtain various hydrogen storage alloy powders having the same CaCu5 crystal structure and having various compositions. Also, as Hinu, MmCo
s powder was obtained.

The various hydrogen storage alloy powders obtained in this manner were mixed uniformly in a flat plate with 80% heavy wax, 10% acetylene black as a heating material, and 10% fluororesin powder as a polishing agent in a flat plate. Convert B+iI to w,N. Then, the obtained kneaded material was wrapped in Niraguru wire mesh and 3 ton
A hydrogen-absorbing F#lL'wt electrode whose outer circumference was covered with a Niraglu wire mesh was produced by pressurizing the electrode with Z-. This hydrogen storage electrode has a structure in which the outer circumference is covered with a Niraglu wire mesh.During photovoltage, the hydrogen storage electrode in the electrode absorbs hydrogen and generates hydrogen gas, resulting in expansion of the electrode caused by the nickel wire mesh. This suppresses the deterioration of mechanical strength due to the expansion of the electrode and the accompanying falling off of the Motosu storage alloy, thereby suppressing early deterioration of performance due to repeated charging and discharging. The amount of alloy powder used in these hydrogen-based J electrodes was approximately 1.5 g.

Next, the above hydrogen storage electrode was combined with a sintered Niraglu positive electrode with a theoretical capacity of 600 mAH, and a sealed Niraglu hydrogen alkaline storage battery was fabricated using a potassium hydroxide aqueous solution, and the negative electrode was made of alloy powder used as a hydrogen storage material. Depending on the seed iron, these batteries are designated as batteries A to Q as shown in Table 1. In addition, these batteries were charged at a current of 0.10 for 16 hours and discharged at a current of 0.20, and the current pressure was 1. Cycle characteristics when charging and discharging were repeatedly performed under cycle conditions in which discharging was stopped when Ov was reached are shown in FIG. 1, with the initial capacity of 6 batteries set as 100, and the discharge capacity is shown in Table 1.

Table 1 From Table 1, it is clear that 1m (based on os) Mitsushimetal 'E7' (in the alloy) partially contains cobalt, Si%Ti, V%Nis Fe%Zns Y%Zr.
, NblMo%Hf%Ta, and an alloy substituted with an element selected from Alkali Douta Kima.Batteries B to Q each have a negative electrode with MmCos. , A, the discharge capacity has increased. In particular, the effects on battery life, E, and O are remarkable, and the discharge capacity is significantly improved. In addition, as for the cycle characteristics, as is clear from the first test, the four ponds B to Q are better than the four ponds aA, and the cycle characteristics of C, 1% l and J are particularly excellent.

As described above, when an alloy containing each of the oak elements shown in Table 1 as a MmCos'r base is used as a hydrogen storage material for the negative electrode, the discharge capacity and cycle characteristics are improved. Yota M
Improvements in discharge capacity and cycle characteristics are also observed when using an alloy containing two or more elements using mCOs as a base. Therefore, it is important to improve the performance of 11L4VIg by appropriately containing two or more elements depending on the purpose. An example in which an alloy containing MmCos as a base and two elements is used as a hydrogen storage material for the negative electrode will be shown below.

Mma9Tia+Coa, aZnc by the same operation as above
2, MmCotsZna+Mou+, Mmα5TiII
An alloy powder consisting of L+Zr+:zCos was prepared, and these alloys were used as a hydrogen storage material for a negative electrode. The L pond was assembled and its capacity and cycle characteristics were measured. The battery thus produced was tested for different types of hydrogen-absorbing material for the negative electrode.
Table 2 shows the discharge capacity, and FIG. 2 shows the cycle characteristics of the batteries R, S, and T.

(G) Effects of the Invention The hydrogen storage electrode of the present invention has Si, Ti%V, Ni, Fe%Zn%Y, Z in Mitsushimekuru cobalt alloy.
C containing at least one element selected from r, Nb, Mo, Hf, Ta and alkaline earth.
It is equipped with an alloy containing four crystals of aCu5 structure, and it improves discharge capacity and cycle characteristics, so it can provide an excellent performance of electricity storage.
Its industrial value is extremely large.

[Brief explanation of the drawing]

Figure 1 shows an electrode using the hydrogen storage electrode according to the present invention as a negative electrode.
Figure 2 shows the cycle characteristics of batteries B to Q and specific soft battery A, and Figure 2 shows the cycle characteristics of batteries R, S and T using the hydrogen storage electrode according to the present invention as the negative electrode.
FIG.

Claims (1)

[Claims] (1) Mitsushi Metal-Cobalt alloy with Si, Ti, and V
, Ni, Fe, Zn, Y, Zr, Nb, Mo, Hf, T
A hydrogen storage electrode characterized in that it includes an alloy having a crystal structure of CaCu_5 structure and containing at least one element selected from a and alkaline earth metals.