JPS5832365A - Mold nickel electrode - Google Patents

Abstract

PURPOSE:To produce a nickel electrode having high energy density by adding the tetravalent nickel oxide hydrate having high filling density in the nickel oxide as the main active substance thereby increasing the filling density of the nickel active substance and increasing the cell capacity. CONSTITUTION:The powder compound composed of 80wt% of nickel oxide powder as the main active substance, 5wt% of the metal nickel powder as the conductive agent, 10wt% of carbon powder and 5wt% of polyethylene as the binder is added with 1-10wt% of tetravalent nickel hydrate (NiO2.H2O) to produce the mixed powder which is molded under the preliminary molding pressure of 200kg/cm<2>. Then said molded pellet is covered with the nickel mesh of 100 mesh and finally molded with 300kg/cm<2>.

Description

Detailed Description of the Invention The present invention is a molded Nirake A/11% % O. As a positive electrode active material in an alkaline secondary battery, it is found in a nickel-cadmium battery, a nickel μ-zinc battery, or a fukeru iron battery. So = Tsuke A/ is the most excellent and useful.

In recent years, however, electronic equipment has become more cordless and electronic equipment has become more compact, and along with this, there has been a demand for smaller batteries, which serve as power sources for equipment, and higher energy density.

In terms of energy density, nickel electrodes are very inferior to other positive electrodes, such as silver oxide electrodes (1iK). The burr is caused by poor utilization of the nickel electrode. Therefore, □Improving the energy density of a nickel electrode 011Fi depends on how much active material can be packed in, and how well the packed active material can be reacted with KltJ rate to increase the utilization rate.

As a result of various unexpected studies, the inventors believe that
By adding tetravalent nickel oxide hydrate powder to the main active material hydroxide = 7 ke powder, the packing density of the nickel active material can be increased without reducing the utilization rate, thereby increasing the energy density. I found out that the same thing applies.

The present invention is based on the above-mentioned dormitory, and examples thereof will be described in detail below.

801% by weight of EFCEL hydroxide powder as the main active material, 51% by weight of nickel metal powder as a conductive agent, 1% by weight of carbon powder
Tetravalent nickel oxide hydrate (Ni-0
Pre-molding pressure 200 #/
d'c molding, after molding, cover the pellet with 100mm V202μ wire mesh, and then final f at 500#/d.
i! II and used as a nickel electrode.

Figure 1 shows the changes in the thickness (m) and utilization rate (dashed line) of a nickel electrode with respect to the addition of the tetravalent nickel oxide μ aqueous phase.As for the thickness, as the amount added increases, it becomes thinner and the packing density increases. As for the utilization rate, it can be seen that when the amount added is 5% by weight, there is no change compared to the case where no additive is added, and when the amount is more than that, it becomes slightly poorer.

Note that the electrode is used within a range that can increase the capacity in relation to the packing density and utilization rate of the nickel active material at the same thickness.

Figure 2 shows the change in capacity when the amount of tetravalent nickel oxide hydrate added is changed in a nickel-zinc battery made by combining the nickel electrode mentioned above and the Marichi O zinc electrode. It can be seen that when the amount added is in the range of 1 to 10% by weight, the capacity increases compared to when it is not added and when it exceeds 10% by weight.

The details of the ring 111Fi in which the packing density is increased by adding tetravalent nickel oxide hydrate are unknown. However, tetravalent O
When a molded body made of nickel oxide hydrate alone was compared with a molded body made of the same amount of nickel hydroxide I&/ alone, the former was thinner and stronger. From this, the nickel oxide hydrate of 4-Y has a high packing density.
It is considered to have am-staining properties.

In addition, considering the reason why the utilization rate of nickel active material hardly decreases by adding -4-valent nickel oxide hydrate, it is found that since the 4-valent O oxide hydrate is a higher-order oxide, During charging reaction of nickel active material, that is, N1tOE
)t→Ni0OHO This is thought to be because it acts as the nucleus of nroom in the reaction process.

As mentioned above, the present invention relates to a molded nickel electrode, and by adding tetravalent nickel oxide hydrate with a high packing density to nickel hydroxide A/ as the main active material, nickel hydroxide can be formed.
The present invention provides a nickel electrode that increases the battery capacity by increasing the active material O packing density and has a high two-μg density, and its industrial value is extremely large.

4+ - Simple surface - Shimei No. 1a shows the change in the thickness of the nickel electrode (91! cycles) and the change in utilization rate (dashed line) with respect to the amount of tetravalent nickel oxide hydrate added -, No. 2m shows the change in the utilization rate (dashed line) Nickel electrodes with varying amounts of hydrate added were used;

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Claims (1)

[Claims] ■ A molding method in which a mixed powder containing nickel hydroxide powder as the main active material and tetravalent nickel oxide hydrate powder is pressed into an acid mold; . ■ Claim No. 1 in which the amount of the tetravalent O nickel hydrate added is 1 to 10% by weight based on the amount of hydroxide = dandruff N.
Kiyoshi Seki's Fl! , Il! Type 1 nickel IK view.