JP2018029045A - Electrode, electrode assembly, and nickel zinc battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode for a nickel zinc battery that can achieve desirable high battery performance while suppressing a reduction in performance even when the electrode as a whole is designed to be thick.SOLUTION: There is provided an electrode that is used as a positive pole or a negative pole of a nickel zinc battery, the electrode including an electrode layer being the positive pole or the negative pole, and the electrode layer including an opening for promoting infiltration of electrolyte into the inside of the electrode on at least one face of the electrode layer.SELECTED DRAWING: Figure 1A

Description

  The present invention relates to an electrode, an electrode assembly, and a nickel zinc battery.

  Although nickel zinc secondary batteries have been developed and studied for a long time, they have not yet been put into practical use. This is because the zinc constituting the negative electrode produces dendritic crystals called dendrite during charging, and this dendrite breaks through the separator and causes a short circuit with the positive electrode. On the other hand, nickel cadmium batteries and nickel metal hydride batteries have already been commercialized. However, the nickel-zinc secondary battery has an extremely high theoretical capacity density of about 5 times that of the nickel-cadmium secondary battery, 2.5 times that of the nickel-hydrogen secondary battery, and 1.3 times that of the lithium-ion battery. And the raw material price is low. Therefore, a technique for preventing a short circuit due to zinc dendrite in a nickel zinc secondary battery is strongly desired.

For example, in Patent Document 1 (International Publication No. 2013/118561), a separator made of a hydroxide ion conductive inorganic solid electrolyte is provided between a positive electrode and a negative electrode for the purpose of preventing a short circuit due to zinc dendrite. Nickel zinc secondary batteries have been proposed. The inorganic solid electrolyte body has a relative density of 90% or more, the general ^{_{formula: M 2+ 1-x M 3+}} x (OH) layered double hydroxide having a basic composition of _{2 A n- x / n · mH} 2 O It is disclosed in this document that it can consist of things. In the formula, M ²⁺ is at least one or more divalent cations, M ³⁺ is at least one or more trivalent cations, A ^n-is the n-valent anion, n Is an integer of 1 or more, and x is 0.1 to 0.4.

International Publication No. 2013/118561 International Publication No. 2016/006330

The present applicant has succeeded in developing a ceramic separator (inorganic solid electrolyte separator) that has hydroxide ion conductivity but is highly densified so as not to have water permeability. Moreover, the present inventors have succeeded in forming such a ceramic separator on a porous substrate (for example, an alumina porous substrate), and the applicant has already proposed a nickel-zinc battery equipped with the ceramic separator (for example, Patent Document 2 (see International Publication No. 2016/006330). When a secondary battery such as a nickel zinc battery is configured using such a separator (or a separator with a porous base material), a short circuit or the like due to zinc dendrite can be effectively prevented. On the other hand, the ceramic separator as described above can be expensive because of its high performance. For this reason, it is desirable that the ceramic separator mounted on the battery is designed to have a relatively small area. In this case, since the area of the electrode must also be reduced, it is desirable to increase the thickness of the electrode in order to increase the battery capacity. However, in the case of a nickel-zinc battery, it is necessary to exchange OH ⁻ between the positive and negative electrodes along with charge / discharge, but if a thick electrode is used, the movement of OH ⁻ on the back side of the electrode (the side far from the counter electrode) is hindered, As a result of the increased resistance, the discharge capacity is reduced. Therefore, an electrode for a nickel zinc battery that can suppress a decrease in performance even when the electrode is thick is desired.

  The inventors of the present invention are now a case where a thick electrode is formed by using an electrode layer provided with an opening for promoting the penetration of the electrolyte into the electrode as a positive electrode or a negative electrode in a nickel zinc battery. In addition, it was found that desirable high battery performance can be realized while suppressing a decrease in performance.

  Accordingly, an object of the present invention is to provide an electrode for a nickel-zinc battery that can achieve a desirable high battery performance while suppressing a decrease in performance even if it is designed to be thick as a whole.

According to one aspect of the present invention, an electrode used as a positive electrode or a negative electrode in a nickel zinc battery,
The electrode includes an electrode layer that is a positive electrode or a negative electrode,
An electrode is provided in which the electrode layer includes an opening for promoting penetration of the electrolyte into the electrode on at least one surface of the electrode layer.

  According to another aspect of the present invention, there is provided an electrode assembly including two or more of the electrodes, wherein the two or more electrodes are arranged in parallel to each other.

According to another aspect of the present invention, a positive electrode comprising nickel hydroxide and / or nickel oxyhydroxide,
A positive electrode electrolyte solution containing an alkali metal hydroxide aqueous solution in which the positive electrode is immersed;
A negative electrode comprising zinc and / or zinc oxide;
A negative electrode electrolyte solution containing an alkali metal hydroxide aqueous solution in which the negative electrode is immersed;
A sealed container containing the positive electrode, the positive electrode electrolyte, the negative electrode, and the negative electrode electrolyte;
In the sealed container, provided to partition the positive electrode chamber containing the positive electrode and the positive electrode electrolyte and the negative electrode chamber containing the negative electrode and the negative electrode electrolyte, and has hydroxide ion conductivity. A ceramic separator made of an inorganic solid electrolyte body;
A nickel zinc battery is provided in which at least one of the positive electrode and the negative electrode is the electrode or the electrode assembly.

It is a figure which shows typically an example of the electrode by this invention. It is an example of the 1B-1B sectional view of the electrode shown by FIG. 1A. It is the other example of the 1B-1B sectional view of the electrode shown by FIG. 1A. It is a figure which shows typically another example of the electrode by this invention. It is the 2B-2B sectional view taken on the line of the electrode shown by FIG. 2A. It is a figure which shows typically another example of the electrode by this invention. It is an example of the 3B-3B sectional view of the electrode shown by FIG. 3A. It is the other example of the 3B-3B sectional view of the electrode shown by FIG. 3A. It is a figure which shows typically another example of the electrode by this invention. It is the 4B-4B sectional view taken on the line of the electrode shown by FIG. 4A. It is a figure which shows typically another example of the electrode by this invention. It is the 5B-5B sectional view taken on the line of the electrode shown by FIG. 5A. It is a conceptual diagram which shows an example of a nickel zinc battery typically. It is a schematic cross section showing one mode of a separator with a porous substrate. It is a schematic cross section which shows the other one aspect | mode of a separator with a porous base material. It is a schematic diagram which shows a layered double hydroxide (LDH) plate-like particle. It is a figure which shows the relationship between the aperture ratio measured in Examples 1-20, and discharge capacity. 2 is a SEM image of the surface of an alumina porous substrate produced in Example 21. FIG. FIG. 6 is an XRD profile obtained for the crystal phase of the sample in Example 21. FIG. 22 is a SEM image showing the surface microstructure of the film sample observed in Example 21. 22 is a SEM image of a polished cross-sectional microstructure of a composite material sample observed in Example 21. FIG. 22 is an exploded perspective view of a denseness discrimination measurement system used in Example 21. FIG. 22 is a schematic cross-sectional view of a denseness discrimination measurement system used in Example 21. FIG. It is a conceptual diagram which shows an example of a He transmittance | permeability measurement system. It is a schematic cross section of the sample holder used in the measurement system shown in FIG. 16A and its peripheral configuration. It is a conceptual diagram which shows an example of a Zn permeation | transmission ratio measuring apparatus. It is a schematic cross section of the sample holder used for the measuring apparatus shown in FIG. 17A. 6 is a graph showing the relationship between the He transmittance measured in Example 5 and the Zn transmission ratio.

Electrode TECHNICAL FIELD This invention relates to the electrode used as a positive electrode or a negative electrode in a nickel zinc battery (typically nickel zinc secondary battery). An example of an electrode is shown in FIGS. 1A and 1B. As shown in FIGS. 1A and 1B, the electrode 2 (typically an electrode plate) of the present invention includes an electrode layer 4 that is a positive electrode or a negative electrode, and the electrode layer 4 is at least one surface of the electrode layer 4. In addition, an opening 6 is provided for promoting the penetration of the electrolyte into the electrode. Thus, by using the electrode layer 4 provided with the opening 6 for promoting the penetration of the electrolytic solution into the electrode as a positive electrode or a negative electrode in a nickel zinc battery, the overall performance can be improved while making the electrode thicker. Desirably high battery performance can be realized while suppressing the decrease.

By the way, in a conventional liquid battery, when the electrode thickness is increased to increase the capacity, problems such as the electrolyte not sufficiently penetrating into the electrode may occur. It was common to ensure. On the other hand, as described above, when the area of the separator and the electrode must be reduced due to the adoption of the high-performance ceramic separator, it is desired to increase the thickness of the electrode in order to increase the battery capacity. However, in the case of a nickel-zinc battery, it is necessary to exchange OH ⁻ between the positive and negative electrodes along with charge / discharge, but if a thick electrode is used, the movement of OH ⁻ on the back side of the electrode (the side far from the counter electrode) is hindered, As a result of the increased resistance, the discharge capacity is reduced. With respect to such a problem, according to the electrode 2 of the present invention, the opening 6 promotes the movement of OH ^{− in} the electrode depth direction, so that a high discharge capacity can be obtained even with a thick electrode. As a result, according to the present invention, it is possible to provide an electrode for a nickel-zinc battery, which can realize a desirable high battery performance while suppressing a decrease in performance even if it is designed to be thick as a whole.

  The electrode layer 4 may be either a positive electrode or a negative electrode. In particular, the electrode 2 is preferably a positive electrode. In this case, the electrode layer as the positive electrode preferably contains at least one of nickel hydroxide and nickel oxyhydroxide. Alternatively, the electrode 2 may be a negative electrode. In this case, the electrode layer as the negative electrode preferably contains at least one of zinc and zinc oxide. Detailed descriptions of the positive electrode and the negative electrode will also be described later.

  The electrode layer 4 preferably has a thickness of 500 μm or more, more preferably 0.5 to 4 mm, still more preferably 0.5 to 3 mm, and particularly preferably 0.5 to 2.5 mm. Most preferably, it is 0.5-2 mm. Here, the thickness of the electrode layer 4 means the distance from one surface of the electrode layer 4 to the other surface (opposite surface) regardless of the presence or absence of other components in the electrode layer 4. And Therefore, as shown in FIG. 5B, even when the electrode layer 4 includes the conductive core 8 ′, the other side from the one surface of the electrode layer 4 including the thickness of the conductive core 8 ′ is included. It means the distance to the surface. In any case, when the thickness is within the above range, the electrolytic solution can penetrate more efficiently into the electrode layer 4 while realizing the battery capacity.

  The electrode layer 4 has an opening 6 on at least one surface of the electrode layer 4 for promoting the penetration of the electrolytic solution into the electrode. The opening 6 may have any shape that contributes to promoting the penetration of the electrolyte, but typically has a shape derived from artificial processing. Therefore, the opening 6 typically has a geometric shape, and typical examples of the geometric shape include a round hole, a square hole, a hexagonal hole, an oblong hole, an oblong hole, a diamond Examples include various holes such as holes, and various slits such as straight slits and curved slits. Preferable examples of drilling include drilling, electrical discharge machining, laser machining, and punching. Preferable examples of the slit processing include notching processing using punches and punching processing. The number of openings 6 may be one, but a plurality of openings 6 is preferable in that the penetration of the electrolyte into the electrode can be more effectively promoted. For example, when the opening is a hole, the diameter of the hole is preferably 100 μm or more, more preferably 300 to 5000 μm, and still more preferably 500 to 1000 μm. The diameter of the hole here means a short diameter when the hole has a long diameter and a short diameter. When the opening is a slit, the width of the slit is preferably 100 μm or more, more preferably 300 to 5000 μm, and still more preferably 500 to 1000 μm. The opening 6 preferably penetrates the electrode layer 4 as shown in FIG. 1B, that is, is configured as a through hole, but does not penetrate the electrode layer 4 as shown in FIG. 1C, that is, does not penetrate. It may be configured as a hole. Moreover, like the electrode 2 'shown in FIGS. 2A and 2B, the openings 6 as non-through holes may be provided alternately from both sides of the electrode 2'. Similarly, in the case of the slit, a slit-like opening 6 ′ may be provided as a through slit as in the electrode 2 ″ shown in FIGS. 3A and 3B, or non-through as shown in FIG. 3C. It may be provided as a slit. 4A and 4B, openings 6 as non-penetrating slits may be alternately provided from both surfaces of the electrode 2 '. In any case, in the present invention, the opening preferably includes at least one of a through hole and a through slit.

  In at least one surface of the electrode layer 4 (that is, the surface having the opening 6), the ratio of the area of the opening 6 to the total area of the electrode layer 4 and the opening 6 is preferably 0.5 to 15%. More preferably, it is 1-10%, More preferably, it is 1-7%, Most preferably, it is 1-5%. By being within these ranges, it is possible to more effectively realize the penetration of the electrolyte into the electrode while realizing a high battery capacity.

  The electrode 2 may be a sintered electrode or a paste (non-sintered) electrode.

  The electrode 2 may have a current collecting terminal 8 at its end. For the current collecting terminal 8, a known current collecting material may be used according to the type of the electrode 2.

  The electrode 2 may have a dense conductive core inside (typically in the center). This form is a typical configuration in a sintered electrode. One end of the conductive core may be extended from the electrode 2 to serve as a current collecting terminal. A known current collecting material may be used for the conductive core according to the type of the electrode 2. Preferable examples of the conductive core include punching metal (a metal plate in which a plurality of holes are formed by punching). In particular, when the conductive core is a current collector plate having holes such as punching metal, as shown in FIGS. 5A and 5B, an opening 6 is provided at a position avoiding the holes 8a of the conductive core 8 ′. This is preferable in that the discharge capacity can be further improved.

  The electrode 2 may not have a dense conductive core. Instead, the electrode 2 may include a porous metal body such as nickel foam (preferably over the entire electrode 2), and this form is a typical configuration in a paste-type (non-sintered) electrode.

  Particularly preferably, two or more electrodes 2 are arranged in parallel to each other to form an electrode assembly or an electrode assembly structure. By using the plurality of electrodes 2 and hence the plurality of electrode layers 4, the total thickness of the electrode layers 4 can be further increased to further improve the battery capacity. In this case, it is preferable from the viewpoint of improving the discharge capacity that the positions of the openings 6 are different between adjacent electrodes 2 (that is, the positions are shifted). The number of the electrodes 2 included in the electrode assembly is preferably 2 or more, more preferably 2 to 10 sheets, still more preferably 2 to 8 sheets, and particularly preferably 2 sheets. ~ 6 sheets, most preferably 2-4 sheets. By using the electrodes 2 in the number as described above, the total thickness can be increased and the battery capacity can be further improved.

  It is preferable that the electrode assembly includes a space for liquid retention (that is, a liquid retention space) between two or more electrode layers 4 arranged in parallel to each other. In this way, since the electrolyte solution can be held in the solution holding space, even if the electrode layer 4 has two or more layers and the total thickness thereof is increased, the electrolyte solution can be sufficiently deep into the electrode layer 4. Can penetrate. It is preferable that the electrode assembly further includes a liquid holding unit capable of holding the liquid in the liquid holding space. More preferably, the electrode assembly includes a liquid retaining means on the outside of the electrode layers 4 at both ends. The liquid holding means is preferably a sheet-like liquid holding member, which functions as a spacer and connecting member between the electrode layers 4 and is preferable in that an electrode assembly can be easily produced. Preferred examples of the liquid retaining member include a nonwoven fabric, a water-absorbing resin, a liquid retaining resin, a porous sheet, and various spacers. Particularly preferred is a nonwoven fabric in that an electrode assembly having good performance can be produced at low cost. For example, the electrode 2 may be entirely wrapped with a nonwoven fabric.

  The liquid holding space or the liquid holding member preferably has a thickness of 0.01 to 0.20 mm, more preferably 0.02 to 0.20 mm, still more preferably 0.02 to 0.15 mm, Especially preferably, it is 0.02-0.10 mm, Most preferably, it is 0.02-0.06 mm. When the thickness is within the above range, a sufficient amount of electrolyte can be held in the liquid retaining space while keeping the overall size of the electrode assembly compact without waste.

  The electrode assembly preferably has a thickness of 1.03 mm or more, more preferably 1.03 to 10 mm, still more preferably 1.03 to 8.0 mm, and particularly preferably 1.03 to 6.mm. 0 mm, most preferably 1.03 to 4.0 mm.

Nickel Zinc Battery FIG. 6 schematically shows an example of a nickel zinc battery equipped with a ceramic separator to which the electrode according to the present invention can be preferably applied. However, it goes without saying that the electrode of the present invention can also be applied to a nickel-zinc battery having a separator other than a ceramic separator. The nickel zinc battery shown in FIG. 6 does not incorporate the electrode 2 for convenience of explanation, but when the electrode 2 is configured as a positive electrode, the positive electrode 12 in FIG. 6 may be replaced with the electrode 2 or the electrode assembly. . On the other hand, when the electrode 2 is configured as a negative electrode, the negative electrode 16 in FIG. 6 may be replaced with the electrode 2 or the electrode assembly. That is, the above-described electrode 2 or electrode assembly may be used as at least one of the positive electrode 12 and the negative electrode 16.

  As shown in FIG. 6, the nickel zinc battery 10 according to the present invention includes a positive electrode 12, a positive electrode electrolyte 14, a negative electrode 16, a negative electrode electrolyte 18, a ceramic separator 20, and a porous substrate 28 in a sealed container 22. It becomes. The positive electrode 12 includes nickel hydroxide and / or nickel oxyhydroxide. The positive electrode electrolyte 14 contains an alkali metal hydroxide aqueous solution, and the positive electrode 12 is immersed therein. The negative electrode 16 contains zinc and / or zinc oxide. The negative electrode electrolyte 18 includes an alkali metal hydroxide aqueous solution, and the negative electrode 16 is immersed therein. The sealed container 22 contains the positive electrode 12, the positive electrode electrolyte 14, the negative electrode 16, and the negative electrode electrolyte 18. If desired, a positive electrode current collector 13 is provided in contact with the positive electrode 12. Further, if desired, a negative electrode current collector 17 is provided in contact with the negative electrode 16.

A ceramic separator 20 (hereinafter referred to as a separator 20) partitions a positive electrode chamber 24 that accommodates the positive electrode 12 and the positive electrode electrolyte solution 14, and a negative electrode chamber 26 that accommodates the negative electrode 16 and the negative electrode electrolyte solution 18 in a sealed container 22. It is provided as follows. The separator 20 has hydroxide ion conductivity. Moreover, it is desired that the separator 20 does not have water permeability. Here, in this specification, “not having water permeability” means that when the water permeability is evaluated by a “denseness determination test” employed in Example 21 described later or a method or configuration according to it, the measurement object ( For example, it means that water that contacts one side of the separator 20 and / or the porous substrate 28) does not permeate the other side. In other words, the fact that the separator 20 does not have water permeability means that the separator 20 has a high degree of denseness that does not allow water to pass through, and is not a porous film or other porous material having water permeability. Means. For this reason, it has a very effective configuration for physically preventing penetration of the separator by zinc dendrite generated during charging and preventing a short circuit between the positive and negative electrodes. Needless to say, the porous substrate 28 may be attached to the separator 20 as shown in FIG. In addition, a resin frame 29 or a resin film is provided on the outer periphery of the separator 20 and / or the porous substrate 28, and the separator 20 and / or the porous substrate 28 are formed in the sealed container 22 through the resin frame 29 or the resin film. It may be sealed and sealed in a liquid-tight manner. In any case, since the separator 20 has hydroxide ion conductivity, it is possible to efficiently move the required hydroxide ions between the positive electrode electrolyte 14 and the negative electrode electrolyte 18, and the positive electrode chamber 24 and the negative electrode. The charge / discharge reaction in the chamber 26 can be realized. The reaction at the time of charging in the positive electrode chamber 24 and the negative electrode chamber 26 is as shown below, and the discharge reaction is reversed.
-Positive electrode: Ni (OH) ₂ + OH ⁻ → NiOOH + H ₂ O + e ⁻
-Negative electrode: ZnO + H ₂ O + 2e ⁻ → Zn + 2OH ⁻

However, the negative electrode reaction is composed of the following two reactions.
-ZnO dissolution reaction: ZnO + H ₂ O + 2OH ⁻ → Zn (OH) ₄ ²⁻
-Zn precipitation reaction: Zn (OH) ₄ ^2- + 2e ⁻ → Zn + 4OH ⁻

The separator separator 20 is a member having hydroxide ion conductivity, and typically has a plate shape, a film shape, or a layer shape. The separator 20 is provided in the sealed container 22, and partitions the positive electrode chamber 24 that stores the positive electrode 12 and the positive electrode electrolyte 14, and the negative electrode chamber 26 that stores the negative electrode 16 and the negative electrode electrolyte 18. As described above, it is desirable that the separator 20 does not have water permeability.

The separator 20 preferably has a He permeability per unit area of 10 cm / min · atm or less, more preferably 5.0 cm / min · atm or less, and still more preferably 1.0 cm / min · atm or less. A separator having a He permeability of 10 cm / min · atm or less can very effectively suppress Zn permeation in the electrolytic solution. For example, as shown in FIG. 18 described later, when the He permeability is 10 cm / min · atm or less, the Zn transmission rate per unit area when evaluated under water contact is significantly reduced. In that sense, it can be said that the upper limit value of the He permeability of 10 cm / min · atm has a critical significance regarding the Zn permeation suppressing effect in the hydroxide ion conductive separator. Thus, it is thought that the separator of this embodiment can suppress the growth of zinc dendrite effectively when used in a nickel zinc secondary battery because Zn permeation is remarkably suppressed. The He permeability is obtained by supplying He gas to one side of the separator and allowing the He gas to pass through the separator, and calculating the He permeability and evaluating the denseness of the hydroxide ion conductive separator. Measured. The He permeability is calculated by the following formula: F / (P × S) using the permeation amount F of He gas per unit time, the differential pressure P applied to the separator during He gas permeation, and the membrane area S through which He gas permeates. calculate. Thus, by evaluating the gas permeability using He gas, it is possible to evaluate the presence or absence of denseness at a very high level, and as a result, substances other than hydroxide ions (especially zinc dendrite growth can be performed). It is possible to effectively evaluate a high degree of compactness such that Zn that is caused is not transmitted as much as possible (only a very small amount is transmitted). This is because the He gas has the smallest structural unit among a wide variety of atoms or molecules that can constitute the gas, and the reactivity is extremely low. That is, He forms He gas by a single He atom without forming a molecule. In this respect, since hydrogen gas is composed of H ₂ molecules, a single He atom is smaller as a gas constituent unit. In the first place, H ₂ gas is dangerous because it is a combustible gas. Then, by adopting the He gas permeability index defined by the above-described formula, objective evaluation regarding the denseness can be easily performed regardless of differences in various sample sizes and measurement conditions. Thus, it can be simply, safely and effectively evaluated whether or not the separator has a sufficiently high density suitable for a nickel zinc battery separator. The measurement of He permeability can be preferably performed according to the procedure shown in Example 23 described later.

The separator 20 preferably has a Zn permeation ratio of 10 m ⁻² · h ⁻¹ or less, more preferably 5.0 m ⁻² · h ⁻¹ or less, when evaluated under contact with water. It is 4.0 m ⁻² · h ⁻¹ or less, more preferably 3.0 m ⁻² · h ⁻¹ or less, more preferably 1.0 m ⁻² · h ⁻¹ or less. Thus, the low Zn permeation ratio means that the permeation of Zn can be extremely effectively suppressed in the electrolytic solution. For this reason, it is thought in principle that the growth of zinc dendrite can be effectively suppressed when used in a nickel zinc secondary battery. The Zn transmission rate is determined through a step of allowing Zn to pass through the separator for a predetermined time and a step of calculating the Zn transmission rate. For the permeation of Zn into the separator, the first aqueous solution containing Zn is brought into contact with one surface of the hydroxide ion conducting separator, and the second aqueous solution or water not containing Zn is introduced into the other surface of the separator. This is done by contacting them. Further, the Zn transmission ratio is calculated by the formula (C ₂ × V ₂ ) / (C ₁ × V ₁ × t × S). Here, the Zn concentration C ₁ of the first aqueous solution before the start of Zn permeation, the liquid volume V ₁ of the first aqueous solution before the start of Zn permeation, the Zn concentration C ₂ of the second aqueous solution or water after the end of Zn permeation, The amount V ₂ of the second aqueous solution or water after the completion of Zn permeation, the permeation time t of Zn, and the film area S through which Zn permeates. The units of the parameters C ₁ , C ₂ , V ₁ , V ₂ , t and S are particularly limited as long as the units of the concentrations C ₁ and C ₂ are aligned and the units of the liquid amounts V ₁ and V ₂ are aligned. However, it is preferable that the unit of Zn transmission time t is h and the unit of film area S is m ² . The Zn concentration C ₁ of the first aqueous solution before Zn permeation is preferably in the range of 0.001 to ₁ mol / L, more preferably 0.01 to 1 mol / L, and still more preferably 0.05 to 0. 8 mol / L, particularly preferably 0.2 to 0.5 mol / L, most preferably 0.35 to 0.45 mol / L. The Zn permeation time is preferably 1 to 720 hours, more preferably 1 to 168 hours, still more preferably 6 to 72 hours, and particularly preferably 12 to 24 hours. Thus, by evaluating Zn permeability using a Zn-containing aqueous solution and a Zn-free solution, it is possible to evaluate the presence or absence of denseness at an extremely high level. It is possible to reliably and highly accurately evaluate high-density such that Zn that causes growth is not transmitted as much as possible (only a very small amount is transmitted). Then, by adopting an index called Zn transmission rate defined by the above-described formula, objective evaluation regarding denseness can be easily performed regardless of differences in various sample sizes and measurement conditions. This Zn transmission rate can be an effective index for judging the difficulty of precipitation of zinc dendrite. This is because when a hydroxide ion conductive separator is used as a separator in a zinc secondary battery, it is considered as follows. That is, even if Zn is contained in the negative electrode electrolyte on one side (zinc negative electrode side) of the separator, if the Zn does not permeate through the positive electrode electrolyte on the other side (originally not containing Zn), the positive electrode electrolyte This is because the growth of zinc dendrite therein is considered to be effectively suppressed. Thus, according to this aspect, it is possible to reliably and accurately evaluate whether or not the separator has sufficiently high density suitable for a nickel zinc battery separator. The measurement of the Zn transmission ratio can be preferably performed according to the procedure shown in Example 23 described later.

  The separator 20 is preferably made of an inorganic solid electrolyte body. By using a hydroxide ion conductive inorganic solid electrolyte as the separator 20, the electrolyte solution between the positive and negative electrodes is isolated and the hydroxide ion conductivity is ensured. And since the inorganic solid electrolyte which comprises the separator 20 is typically a dense and hard inorganic solid, the penetration of the separator by the zinc dendrite produced | generated at the time of charge is blocked physically, and the short circuit between positive and negative electrodes is prevented. Is possible. As a result, the reliability of the nickel zinc battery can be greatly improved. It is desirable that the inorganic solid electrolyte body is so dense that it does not have water permeability. For example, the inorganic solid electrolyte body preferably has a relative density of 90% or more, more preferably 92% or more, and even more preferably 95% or more, calculated by the Archimedes method, but prevents penetration of zinc dendrite. It is not limited to this as long as it is as dense and hard as possible. Such a dense and hard inorganic solid electrolyte body can be produced through a hydrothermal treatment. Therefore, a simple green compact that has not been subjected to hydrothermal treatment is not preferable as the inorganic solid electrolyte body of the present invention because it is not dense and is brittle in solution. Of course, any manufacturing method can be used as long as a dense and hard inorganic solid electrolyte body can be obtained, even if it has not undergone hydrothermal treatment.

  The separator 20 or the inorganic solid electrolyte body may be a composite of a particle group including an inorganic solid electrolyte having hydroxide ion conductivity and an auxiliary component that assists densification and hardening of the particle group. Good. Alternatively, the separator 20 includes an open-pore porous body as a base material and an inorganic solid electrolyte (for example, layered double hydroxide) deposited and grown in the pores so as to fill the pores of the porous body. It may be a complex. Examples of the substance constituting the porous body include ceramics such as alumina and zirconia, and insulating substances such as a porous sheet made of a foamed resin or a fibrous substance.

The inorganic solid electrolyte body preferably contains a layered double hydroxide (LDH), and more preferably comprises such LDH. Typically, LDH has a basic composition of the general formula: M ²⁺ _1-x M ³⁺ _x (OH) ₂ A ⁿ⁻ _{x / n} · mH ₂ O, where M ²⁺ is divalent is a ^{cation, M 3+} is a trivalent ^{cation, a n-is} the n-valent anion, n is an integer of 1 or more, x is 0.1 to 0.4, m Is 0 or more. In the above general formula, M ²⁺ may be any divalent cation, and preferred examples include Mg ²⁺ , Ca ²⁺ and Zn ²⁺ , and more preferably Mg ²⁺ . M ³⁺ may be any trivalent cation, but preferred examples include Al ³⁺ or Cr ³⁺ , and more preferred is Al ³⁺ . A ^n- may be any anion, preferred examples OH ^- and _CO ^{3 2-} and the like. Therefore, in the general ^{formula, M 2+} comprises ^{Mg 2+, M 3+} comprises ^{Al 3+, A n-is} OH ^- and / or _CO preferably contains ^{3 2-.} n is an integer of 1 or more, preferably 1 or 2. x is 0.1 to 0.4, preferably 0.2 to 0.35. It is also possible to replace the part or all of the M ³⁺ in the general formula tetravalent or higher valency cation, in which case, the anion A ^n- coefficients x / n of the above general formula It may be changed as appropriate. m is an arbitrary number which means the number of moles of water, and is a real number or an integer of 0 or more, typically more than 0 or 1 or more.

  The inorganic solid electrolyte is preferably densified by hydrothermal treatment. Hydrothermal treatment is extremely effective for the densification of layered double hydroxides, especially Mg—Al type layered double hydroxides. Densification by hydrothermal treatment is performed, for example, as described in Patent Document 1 (International Publication No. 2013/118561), in which pure water and a plate-like green compact are placed in a pressure vessel, and 120 to 250 ° C., preferably The reaction can be performed at a temperature of 180 to 250 ° C. for 2 to 24 hours, preferably 3 to 10 hours. However, a more preferable production method using hydrothermal treatment will be described later.

  The porous substrate 28 may be provided on one side or both sides of the separator 20. When the porous substrate 28 is provided on one side of the separator 20, the porous substrate 28 may be provided on the surface of the separator 20 on the negative electrode 16 side or on the surface of the separator 20 on the positive electrode 12 side. It goes without saying that the porous base material 28 has water permeability, and therefore, the positive electrode electrolyte 14 and the negative electrode electrolyte 18 can reach the separator 20. It is also possible to hold hydroxide ions more stably. In addition, since the strength can be imparted by the porous substrate 28, the separator 20 can be made thin to reduce the resistance. In addition, a dense film or a dense layer of an inorganic solid electrolyte (preferably LDH) can be formed on or in the porous substrate 28. In the case of providing a porous substrate on one side of the separator 20, a method of preparing a porous substrate and depositing an inorganic solid electrolyte on the porous substrate can be considered (this method will be described later). In FIG. 6, the porous base material 28 is provided over the entire surface of one side of the separator 20, but may be provided only on a part of one side of the separator 20 (for example, a region involved in the charge / discharge reaction). For example, when the inorganic solid electrolyte is formed in the form of a film or a layer on or in the porous substrate 28, the porous substrate 28 is provided over the entire surface of one side of the separator 20 due to the manufacturing method. It is typical to become. On the other hand, when the inorganic solid electrolyte body is formed in a self-supporting plate shape (which does not require a base material), the porous base material 28 is provided only on a part of one side of the separator 20 (for example, a region involved in the charge / discharge reaction). May be retrofitted, or the porous substrate 28 may be retrofitted over the entire surface of one side.

The inorganic solid electrolyte body may be in the form of a plate, a film, or a layer. When the inorganic solid electrolyte is in the form of a film or a layer, the film or layer of the inorganic solid electrolyte is on the porous substrate or its It is preferably formed in the inside. When the plate-like form is used, sufficient hardness can be secured and penetration of zinc dendrites can be more effectively prevented. On the other hand, if the film or layer form is thinner than the plate, there is an advantage that the resistance of the separator can be significantly reduced while ensuring the minimum necessary hardness to prevent the penetration of zinc dendrite. is there. The preferred thickness of the plate-like inorganic solid electrolyte body is 0.01 to 0.5 mm, more preferably 0.02 to 0.2 mm, and still more preferably 0.05 to 0.1 mm. Moreover, the higher the hydroxide ion conductivity of the inorganic solid electrolyte body, the better, but it typically has a conductivity of 10 ⁻⁴ to 10 ⁻¹ S / m. On the other hand, in the case of a film-like or layered form, the thickness is preferably 100 μm or less, more preferably 75 μm or less, still more preferably 50 μm or less, particularly preferably 25 μm or less, and most preferably 5 μm or less. Thus, the resistance of the separator 20 can be reduced by being thin. The lower limit of the thickness is not particularly limited because it varies depending on the application, but in order to ensure a certain degree of rigidity desired as a separator film or layer, the thickness is preferably 1 μm or more, more preferably 2 μm or more. is there.

  Further, as described above, a second separator (resin separator) made of a water-absorbing resin such as a nonwoven fabric or a liquid retaining resin is disposed between the positive electrode 12 and the separator 20 and / or between the negative electrode 16 and the separator 20, Even when the electrolyte is decreased, the electrolyte may be held in the reaction portion of the positive electrode and / or the negative electrode. Preferable examples of the water absorbent resin or the liquid retaining resin include polyolefin resins.

The positive electrode 12 (the electrode layer 4 when the electrode 2 is configured as a positive electrode) contains nickel hydroxide and / or nickel oxyhydroxide. For example, nickel hydroxide may be used as the positive electrode 12 when the nickel zinc battery is configured in a discharged state, and nickel oxyhydroxide may be used as the positive electrode 12 when configured in a fully charged state. Nickel hydroxide and nickel oxyhydroxide (hereinafter referred to as nickel hydroxide or the like) are positive electrode active materials generally used in nickel zinc batteries, and are typically in the form of particles. In nickel hydroxide or the like, different elements other than nickel may be dissolved in the crystal lattice, thereby improving the charging efficiency at high temperatures. Examples of such different elements include zinc and cobalt. In addition, nickel hydroxide or the like may be mixed with a cobalt-based component, and examples of such a cobalt-based component include granular materials of metallic cobalt and cobalt oxide (for example, cobalt monoxide). . Furthermore, the surface of particles such as nickel hydroxide (which may contain different elements in solid solution) may be coated with a cobalt compound. Examples of such cobalt compounds include cobalt monoxide, divalent α-type. Examples include cobalt hydroxide, divalent β-type cobalt hydroxide, compounds of higher-order cobalt exceeding 2 valences, and any combination thereof.

  The positive electrode 12 may further contain an additional element in addition to the nickel hydroxide compound and the different element that can be dissolved therein. Examples of such additional elements include Mg, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu, Hf, Ta, W, Mn, Re, Os, Ir, Si, Pt, Au and Hg, and any combination thereof. The inclusion form of the additional element is not particularly limited, and may be contained in the form of a simple metal or a metal compound (for example, oxide, hydroxide, halide, and carbonate). When adding a single metal or a metal compound containing an additional element, the addition amount is preferably 0.5 to 20 parts by weight, more preferably 2 to 5 parts by weight, with respect to 100 parts by weight of the nickel hydroxide compound. It is.

  The positive electrode 12 may be configured as a positive electrode mixture by further including an electrolytic solution or the like. The positive electrode mixture can contain nickel hydroxide compound particles, an electrolytic solution, and optionally a conductive material such as carbon particles, a binder, and the like.

  A positive electrode current collector 13 is preferably provided in contact with the positive electrode 12. As shown in FIG. 6, the positive electrode current collector 13 may penetrate the sealed container 22 and extend to the outside thereof to constitute the positive electrode terminal itself, or the positive electrode terminal provided separately may have a sealed container. It is good also as a structure connected in 22 or outside. Preferable examples of the positive electrode current collector 13 include nickel punching metal, nickel-coated punching metal, and a nickel porous substrate (for example, a foamed nickel plate). In this case, for example, a positive electrode plate made of positive electrode 12 / positive electrode current collector 13 is preferably prepared by uniformly applying a paste containing an electrode active material such as nickel hydroxide on a nickel porous substrate and drying the paste. Can do. At that time, it is also preferable to press the dried positive electrode plate (that is, positive electrode 12 / positive electrode current collector 13) to prevent the electrode active material from falling off and to improve the electrode density.

The negative electrode 16 (the electrode layer 4 when the electrode 2 is configured as a negative electrode) contains zinc and / or zinc oxide. Zinc may be contained in any form of zinc metal, zinc compound and zinc alloy as long as it has an electrochemical activity suitable for the negative electrode. Preferable examples of the negative electrode material include zinc oxide, zinc metal, calcium zincate and the like, and a mixture of zinc metal and zinc oxide is more preferable. The negative electrode 16 may be formed in a gel form, or may be mixed with an electrolytic solution to form a negative electrode mixture. For example, a gelled negative electrode can be easily obtained by adding an electrolytic solution and a thickener to the negative electrode active material. Examples of the thickener include polyvinyl alcohol, polyacrylate, CMC, alginic acid and the like. Polyacrylic acid is preferable because it has excellent chemical resistance to strong alkali.

  As the zinc alloy, a zinc alloy containing no mercury and lead, which is known as a non-free zinc alloy, can be used. For example, a zinc alloy containing 0.01 to 0.06 mass% indium, 0.005 to 0.02 mass% bismuth, and 0.0035 to 0.015 mass% aluminum has an effect of suppressing hydrogen gas generation. Therefore, it is preferable. In particular, indium and bismuth are advantageous in improving the discharge performance. The use of the zinc alloy for the negative electrode can improve the safety by suppressing the generation of hydrogen gas by slowing the self-dissolution rate in the alkaline electrolyte.

  The shape of the negative electrode material is not particularly limited, but it is preferably a powder form, which increases the surface area and can cope with a large current discharge. In the case of a zinc alloy, the preferable average particle diameter of the negative electrode material is in the range of 90 to 210 μm. If the average particle diameter is within this range, the surface area is large, so that it is suitable for dealing with a large current discharge. Easy to mix evenly and easy to handle during battery assembly.

  A negative electrode current collector 17 is preferably provided in contact with the negative electrode 16. As shown in FIG. 6, the negative electrode current collector 17 may penetrate the sealed container 22 and extend to the outside thereof to constitute the negative electrode terminal itself, or the negative electrode terminal provided separately may be connected to the sealed container. It is good also as a structure connected in 22 or outside. A preferred example of the negative electrode current collector 17 is a copper mesh. In this case, for example, a negative electrode plate comprising a negative electrode 16 / a negative electrode current collector 17 by applying a mixture containing zinc oxide powder and / or zinc powder and optionally a binder (for example, polytetrafluoroethylene particles) on a copper mesh. Can be preferably produced. At that time, it is also preferable to press the dried negative electrode plate (that is, negative electrode 16 / negative electrode current collector 17) to prevent the electrode active material from falling off and to improve the electrode density.

The electrolyte positive electrode electrolyte 14 and negative electrode electrolyte 18 contain an alkali metal hydroxide. That is, an aqueous solution containing an alkali metal hydroxide is used as the positive electrode electrolyte 14 and the negative electrode electrolyte 18. Examples of the alkali metal hydroxide include potassium hydroxide, sodium hydroxide, lithium hydroxide, ammonium hydroxide and the like, and potassium hydroxide is more preferable. In order to suppress self-dissolution of the zinc alloy, a zinc compound such as zinc oxide or zinc hydroxide may be added to the electrolytic solution. As described above, the positive electrode electrolyte 14 and the negative electrode electrolyte 18 may be mixed with the positive electrode 12 and / or the negative electrode 16 and exist in the form of a positive electrode mixture and / or a negative electrode mixture. Further, the electrolytic solution may be gelled in order to prevent leakage of the electrolytic solution. As the gelling agent, it is desirable to use a polymer that swells by absorbing the solvent of the electrolytic solution, and polymers such as polyethylene oxide, polyvinyl alcohol, and polyacrylamide, and starch are used.

The hermetic container 22 is a container that hermetically houses the positive electrode 12, the positive electrode electrolyte 14, the negative electrode 16, and the negative electrode electrolyte 18, and has a structure having liquid tightness and air tightness. The material of the sealed container is not particularly limited as long as it has resistance to an alkali metal hydroxide such as potassium hydroxide, and is preferably made of a resin such as polyolefin resin, ABS resin, modified polyphenylene ether, and more preferably. ABS resin or modified polyphenylene ether. The separator 20 may be fixed to the sealed container 22 by various methods, but is preferably fixed by an adhesive having resistance to alkali metal hydroxide such as potassium hydroxide. Moreover, when the polyolefin resin-made airtight container 22 is used, fixing of the separator 20 by heat sealing is also preferable.

LDH separator with porous substrate As described above, the separator with a porous substrate preferably used for the nickel-zinc battery of the present invention is a separator made of an inorganic solid electrolyte having hydroxide ion conductivity and at least one of the separators. And a porous substrate provided on the surface. The inorganic solid electrolyte body is in the form of a film or layer that is so dense that it does not have water permeability. A particularly preferred separator with a porous substrate comprises a porous substrate and a separator layer formed on and / or in the porous substrate, and the separator layer is layered as described above. It contains double hydroxide (LDH). The separator layer preferably has no water permeability. That is, the porous material can have water permeability due to the presence of pores, but the separator layer is preferably densified with LDH to such an extent that it does not have water permeability. The separator layer is preferably formed on a porous substrate. For example, as shown in FIG. 7, the separator layer 20 is preferably formed as an LDH dense film on the porous substrate 28. In this case, needless to say, LDH may also be formed on the surface of the porous substrate 28 and in the pores in the vicinity thereof as shown in FIG. 7 due to the nature of the porous substrate 28. Alternatively, as shown in FIG. 8, LDH is densely formed in the porous substrate 28 (for example, in the surface of the porous substrate 28 and in the pores in the vicinity thereof), whereby at least one of the porous substrates 28 is formed. The part may constitute separator layer 20 '. In this regard, the embodiment shown in FIG. 8 has a configuration in which the membrane equivalent portion in the separator layer 20 of the embodiment shown in FIG. 7 is removed, but is not limited to this, and is parallel to the surface of the porous substrate 28. A separator layer only needs to be present. In any case, since the separator layer is densified with LDH to such an extent that it does not have water permeability, it has hydroxide ion conductivity but does not have water permeability (that is, basically only hydroxide ions. It can have a unique function.

  The porous substrate is preferably capable of forming an LDH-containing separator layer on and / or in the porous substrate, and the material and the porous structure are not particularly limited. Typically, an LDH-containing separator layer is formed on and / or in a porous substrate, but an LDH-containing separator layer is formed on a non-porous substrate and then non-porous by various known techniques. The porous substrate may be made porous. In any case, it is preferable that the porous base material has a porous structure having water permeability in that the electrolyte solution can reach the separator layer when incorporated into the battery as a battery separator.

  The porous substrate is preferably composed of at least one selected from the group consisting of ceramic materials, metal materials, and polymer materials. More preferably, the porous substrate is made of a ceramic material. In this case, preferred examples of the ceramic material include alumina, zirconia, titania, magnesia, spinel, calcia, cordierite, zeolite, mullite, ferrite, zinc oxide, silicon carbide, and any combination thereof. More preferred are alumina, zirconia, titania, and any combination thereof, particularly preferred are alumina and zirconia, and most preferred is alumina. When these porous ceramics are used, it is easy to form an LDH-containing separator layer having excellent denseness. Preferable examples of the metal material include aluminum and zinc. Preferable examples of the polymer material include polystyrene, polyether sulfone, polypropylene, epoxy resin, polyphenylene sulfide, hydrofluorinated fluororesin (tetrafluorinated resin: PTFE, etc.), and any combination thereof. It is more preferable to appropriately select a material excellent in alkali resistance as the resistance to the battery electrolyte from the various preferable materials described above.

  The porous substrate preferably has an average pore diameter of 0.001 to 1.5 μm, more preferably 0.001 to 1.25 μm, still more preferably 0.001 to 1.0 μm, and particularly preferably 0.001. It is -0.75 micrometer, Most preferably, it is 0.001-0.5 micrometer. By setting it within these ranges, it is possible to form an LDH-containing separator layer that is so dense that it does not have water permeability while ensuring desired water permeability in the porous substrate. In the present invention, the average pore diameter can be measured by measuring the longest distance of the pores based on an electron microscope (SEM) image of the surface of the porous substrate. The magnification of the electron microscope (SEM) image used for this measurement is 20000 times, and all obtained pore diameters are arranged in order of size, and the top 15 points and the bottom 15 points from the average value, with 30 points per field of view in total. The average pore diameter can be obtained by calculating an average value for two visual fields. For the length measurement, a length measurement function of SEM software, image analysis software (for example, Photoshop, manufactured by Adobe) or the like can be used.

  The surface of the porous substrate preferably has a porosity of 10 to 60%, more preferably 15 to 55%, and still more preferably 20 to 50%. By setting it within these ranges, it is possible to form an LDH-containing separator layer that is so dense that it does not have water permeability while ensuring desired water permeability in the porous substrate. Here, the porosity of the surface of the porous substrate is adopted because it is easy to measure the porosity using the image processing described below, and the porosity of the surface of the porous substrate. This is because it can be said that it generally represents the porosity inside the porous substrate. That is, if the surface of the porous substrate is dense, the inside of the porous substrate can be said to be dense as well. In the present invention, the porosity of the surface of the porous substrate can be measured as follows by a technique using image processing. That is, 1) An electron microscope (SEM) image (a magnification of 10,000 times or more) of the surface of the porous substrate is acquired. 2) A gray scale SEM image is read using image analysis software such as Photoshop (manufactured by Adobe). 3) A black and white binary image is created by the procedure of [Image] → [Color tone correction] → [2 gradation]. 4) The value obtained by dividing the number of pixels occupied by the black portion by the total number of pixels in the image is defined as the porosity (%). The porosity measurement by this image processing is preferably performed for a 6 μm × 6 μm region on the surface of the porous substrate. In order to obtain a more objective index, three arbitrarily selected regions are used. It is more preferable to employ the average value of the obtained porosity.

When the porous substrate is made of alumina, the bulk density value of the porous substrate obtained by the Archimedes method is preferably 2.45 to 2.70 g / cm ³ , more preferably 2.50 to 2.65 g / cm ^3. More preferably, it is 2.54 to 2.60 g / cm ³ . By setting it within these ranges, strength can be imparted to the porous substrate and resistance components derived from the porous substrate can be suppressed.

  The separator layer is formed on the porous substrate and / or in the porous substrate, preferably on the porous substrate. For example, when the separator layer 20 is formed on the porous substrate 28 as shown in FIG. 7, the separator layer 20 is in the form of an LDH dense film, which is typically made from LDH. Become. Further, when the separator layer 20 ′ is formed in the porous substrate 28 as shown in FIG. 8, the surface of the porous substrate 28 (typically the surface of the porous substrate 28 and the vicinity thereof). Since the LDH is densely formed in the pores), the separator layer 20 ′ is typically composed of at least a part of the porous substrate 28 and LDH. The separator layer 20 ′ shown in FIG. 7 can be obtained by removing a portion corresponding to the film in the separator layer 20 shown in FIG. 7 by a known method such as polishing or cutting.

  The separator layer preferably does not have water permeability (desirably water permeability and air permeability). For example, the separator layer does not allow permeation of water even if one side of the separator layer is brought into contact with water at 25 ° C. for 1 week, and does not allow permeation of helium gas even if helium gas is pressurized on the one side with an internal / external pressure difference of 0.5 atm. . That is, the separator layer is preferably densified with LDH to the extent that it does not have water permeability. However, when a defect having water permeability locally and / or accidentally exists in the functional film, the defect is filled with an appropriate repair agent (for example, epoxy resin) to repair the water impermeability and Gas impermeability may be ensured and such repair agents need not necessarily have hydroxide ion conductivity. In any case, the surface of the separator layer (typically the LDH dense film) preferably has a porosity of 20% or less, more preferably 15% or less, still more preferably 10% or less, and particularly preferably 7%. It is as follows. It means that the lower the porosity of the surface of the separator layer, the higher the density of the separator layer (typically the LDH dense film), which is preferable. Here, the porosity of the surface of the separator layer is adopted because it is easy to measure the porosity using the image processing described below, and the porosity of the surface of the separator layer is determined inside the separator layer. It is because it can be said that the porosity of is generally expressed. That is, if the surface of the separator layer is dense, it can be said that the inside of the separator layer is also dense. In the present invention, the porosity of the surface of the separator layer can be measured as follows by a technique using image processing. That is, 1) An electron microscope (SEM) image (a magnification of 10,000 times or more) of the surface of the separator layer is acquired. 2) A gray scale SEM image is read using image analysis software such as Photoshop (manufactured by Adobe). 3) A black and white binary image is created by the procedure of [Image] → [Color tone correction] → [2 gradation]. 4) The value obtained by dividing the number of pixels occupied by the black portion by the total number of pixels in the image is defined as the porosity (%). The porosity measurement by this image processing is preferably performed for a 6 μm × 6 μm region on the surface of the separator layer. In order to obtain a more objective index, it is obtained for three arbitrarily selected regions. It is more preferable to adopt the average value of the porosity.

  The layered double hydroxide is composed of an aggregate of a plurality of plate-like particles (that is, LDH plate-like particles), and the plurality of plate-like particles have their plate surfaces perpendicular to the surface of the porous substrate (substrate surface). It is preferable that they are oriented in such a direction as to cross each other diagonally. As shown in FIG. 7, this embodiment is an embodiment that can be particularly preferably realized when the separator layer 20 is formed as an LDH dense film on the porous substrate 28. However, as shown in FIG. 8, LDH is densely formed in the porous substrate 28 (typically, the surface of the porous substrate 28 and the pores in the vicinity thereof), whereby the porous substrate 28 is formed. This can also be realized when at least a part of the separator layer 20 ′.

  That is, the LDH crystal is known to have the form of a plate-like particle having a layered structure as shown in FIG. 9, but the vertical or oblique orientation is determined by the LDH-containing separator layer (for example, an LDH dense film). This is a very advantageous property for the user. This is because, in an oriented LDH-containing separator layer (for example, an oriented LDH dense film), the hydroxide ion conductivity in the direction in which the LDH plate-like particles are oriented (that is, the direction parallel to the LDH layer) is perpendicular to this. This is because there is a conductivity anisotropy that is much higher than the conductivity in the direction. In fact, the present applicant has obtained knowledge that the conductivity (S / cm) in the alignment direction is one order of magnitude higher than the conductivity (S / cm) in the direction perpendicular to the alignment direction in the LDH oriented bulk body. ing. That is, the vertical or oblique orientation in the LDH-containing separator layer of the present embodiment indicates the conductivity anisotropy that the LDH oriented body can have in the layer thickness direction (that is, the direction perpendicular to the surface of the separator layer or the porous substrate). As a result, the conductivity in the layer thickness direction can be maximized or significantly increased. In addition, since the LDH-containing separator layer has a layer form, lower resistance can be realized than a bulk form LDH. An LDH-containing separator layer having such an orientation is easy to conduct hydroxide ions in the layer thickness direction. In addition, since it is densified, it is extremely suitable for a separator that requires high conductivity and denseness in the layer thickness direction.

  Particularly preferably, the LDH plate-like particles are highly oriented in the vertical direction in the LDH-containing separator layer (typically an LDH dense film). This high degree of orientation can be confirmed if the (003) plane peak is not detected or is smaller than the (012) plane peak when the surface of the separator layer is measured by X-ray diffraction. It is. However, when using a porous substrate in which a diffraction peak is observed at the same position as the peak due to the (012) plane, the peak of the (012) plane due to the LDH plate-like particles cannot be specified. This is not the case. This characteristic peak characteristic indicates that the LDH plate-like particles constituting the separator layer are oriented in a direction perpendicular to the separator layer (that is, a vertical direction or an oblique direction similar thereto, preferably a vertical direction). That is, the peak on the (003) plane is known as the strongest peak observed when X-ray diffraction is performed on non-oriented LDH powder. However, in the oriented LDH-containing separator layer, the peak of the (003) plane is not detected because the LDH plate-like particles are oriented in the direction perpendicular to the separator layer, or the peak of the (012) plane is not detected. Detected small. This is due to the following reason. That is, since the c-axis direction (00l) plane (l is 3 and 6) to which the (003) plane belongs is a plane parallel to the layered structure of the LDH plate-like particles, the LDH plate-like particles are separated from the separator layer. When oriented in the vertical direction, the LDH layered structure also faces in the vertical direction. As a result, when the surface of the separator layer is measured by the X-ray diffraction method, the peak of the (00l) plane (l is 3 and 6) does not appear or is difficult to appear. In particular, the (003) plane peak tends to be stronger than the (006) plane peak when it exists, so it can be said that it is easier to evaluate the presence of vertical orientation than the (006) plane peak. . Therefore, it can be said that it is preferable that the orientation LDH-containing separator layer does not detect the peak of the (003) plane or detects it smaller than the peak of the (012) plane because it suggests a high degree of orientation in the vertical direction. .

  The separator layer preferably has a thickness of 100 μm or less, more preferably 75 μm or less, further preferably 50 μm or less, particularly preferably 25 μm or less, and most preferably 5 μm or less. Thus, the resistance of the separator can be reduced by being thin. The separator layer is preferably formed as an LDH dense film on the porous substrate. In this case, the thickness of the separator layer corresponds to the thickness of the LDH dense film. When the separator layer is formed in the porous substrate, the thickness of the separator layer corresponds to the thickness of the composite layer composed of at least part of the porous substrate and LDH, and the separator layer is porous. When formed over and in the substrate, this corresponds to the total thickness of the LDH dense film and the composite layer. In any case, when the thickness is as described above, a desired low resistance suitable for practical use in battery applications and the like can be realized. The lower limit of the thickness of the LDH alignment film is not particularly limited because it varies depending on the application, but in order to ensure a certain degree of hardness desired as a functional film such as a separator, the thickness is preferably 1 μm or more. Preferably it is 2 micrometers or more.

  The LDH separator with a porous base material described above is (a) a porous base material is prepared, and (b) a starting material capable of giving a starting point for crystal growth of LDH is uniformly attached to the porous base material, if desired. (C) The porous substrate can be preferably manufactured by subjecting the porous substrate to hydrothermal treatment to form an LDH film.

(A) Preparation of porous substrate The porous substrate is as described above, and is preferably composed of at least one selected from the group consisting of ceramic materials, metal materials, and polymer materials. More preferably, the porous substrate is made of a ceramic material. In this case, preferred examples of the ceramic material include alumina, zirconia, titania, magnesia, spinel, calcia, cordierite, zeolite, mullite, ferrite, zinc oxide, silicon carbide, and any combination thereof. More preferred are alumina, zirconia, titania, and any combination thereof, and particularly preferred are alumina, zirconia (eg, yttria stabilized zirconia (YSZ)), and combinations thereof. Preferable examples of the metal material include aluminum and zinc. Preferable examples of the polymer material include polystyrene, polyether sulfone, polypropylene, epoxy resin, polyphenylene sulfide, hydrofluorinated fluororesin (tetrafluorinated resin: PTFE, etc.), and any combination thereof. When these porous ceramics are used, the density of the LDH film tends to be improved. When using a porous substrate made of a ceramic material, it is preferable to subject the porous substrate to ultrasonic cleaning, cleaning with ion exchange water, and the like.

  As described above, the porous substrate is more preferably composed of a ceramic material. The porous substrate made of a ceramic material may be a commercially available product or may be prepared according to a known technique, and is not particularly limited. For example, after kneading ceramic powder, methylcellulose, and ion-exchanged water at a desired blending ratio, subjecting the obtained kneaded product to extrusion molding, and drying the obtained molded body at 70 to 200 ° C. for 10 to 40 hours A porous substrate made of a ceramic material can be produced by firing at 900 to 1300 ° C. for 1 to 5 hours. In this case, examples of the ceramic powder include zirconia powder, boehmite powder, and titania powder. The blending ratio of methylcellulose is preferably 1 to 20 parts by weight with respect to 100 parts by weight of the ceramic powder. Further, the blending ratio of the ion exchange water is preferably 10 to 100 parts by weight with respect to 100 parts by weight of the ceramic powder.

(B) Attachment of starting material If desired, a starting material that can provide a starting point for crystal growth of LDH may be uniformly attached to the porous substrate. After the starting material is uniformly attached to the surface of the porous substrate in this way, the subsequent step (c) is performed, so that a highly densified LDH film can be uniformly formed on the surface of the porous substrate. It can be formed uniformly. Preferable examples of such an origin include a chemical species that provides an anion that can enter between the layers of LDH, a chemical species that provides a cation that can be a constituent element of LDH, or LDH.

(I) Chemical species that provide anions The starting point of crystal growth of LDH can be a chemical species that provides anions that can enter between layers of LDH. Examples of such anions include CO ₃ ²⁻ , OH ⁻ , SO ₃ ⁻ , SO ₃ ²⁻ , SO ₄ ²⁻ , NO ₃ ⁻ , Cl ⁻ , Br ⁻ , and any combination thereof. It is done. Therefore, the starting material that can provide such a starting point may be uniformly attached to the surface of the porous substrate by an appropriate method according to the type of the starting material. By applying a chemical species that gives an anion to the surface, metal cations such as Mg ²⁺ and Al ³⁺ can be adsorbed on the surface of the porous substrate to generate LDH nuclei. Therefore, by performing the subsequent step (c), a highly densified LDH film can be uniformly formed on the surface of the porous substrate without unevenness.

According to a preferred embodiment of the present invention, the starting material can be attached by attaching a polymer to the surface of the porous substrate and then introducing a chemical species that gives an anion to the polymer. In this embodiment, the anion is preferably SO ₃ ⁻ , SO ₃ ²⁻ and / or SO ₄ ²⁻ , and introduction of a chemical species giving such an anion into the polymer is performed by sulfonation treatment. Is preferred. Polymers that can be used are anionizable (especially sulfonated) polymers, examples of such polymers include polystyrene, polyethersulfone, polypropylene, epoxy resins, polyphenylene sulfide, and any combination thereof. . In particular, the aromatic polymer is preferable in that it is easily anionized (particularly sulfonated). Examples of such aromatic polymer include polystyrene, polyethersulfone, epoxy resin, polyphenylene sulfide, and any of them. Combinations are mentioned. The most preferred polymer is polystyrene. The adhesion of the polymer to the porous substrate is performed by using a solution in which the polymer is dissolved (hereinafter referred to as a polymer solution) as the surface of the porous substrate (preferably, the outermost surface of the plate-like outline of the porous substrate) ) Is preferably applied by coating. The polymer solution can be easily prepared, for example, by dissolving a polymer solid (for example, a polystyrene substrate) in an organic solvent (for example, a xylene solution). It is preferable to prevent the polymer solution from penetrating into the porous substrate because it is easy to achieve uniform coating. In this respect, the polymer solution is preferably attached or applied by spin coating because it can be applied uniformly. The spin coating conditions are not particularly limited. For example, the spin coating may be performed at a rotational speed of 1000 to 10000 rpm for about 60 to 300 seconds including dripping and drying. On the other hand, the sulfonation treatment may be performed by immersing the porous substrate to which the polymer is attached in a sulfonateable acid such as sulfuric acid (for example, concentrated sulfuric acid), fuming sulfuric acid, chlorosulfonic acid, and sulfuric anhydride. Alternatively, the technology may be used. The immersion in the sulfonateable acid may be performed at room temperature or high temperature (for example, 50 to 150 ° C.), and the immersion time is not particularly limited, but is, for example, 1 to 14 days.

According to another preferred embodiment of the present invention, the starting material can be attached by treating the surface of the porous substrate with a surfactant containing a chemical species that gives an anion as a hydrophilic group. In this case, the anion is preferably SO ₃ ⁻ , SO ₃ ²⁻ and / or SO ₄ ²⁻ . A typical example of such a surfactant is an anionic surfactant. Preferred examples of the anionic surfactant include a sulfonic acid type anionic surfactant, a sulfate type anionic surfactant, and any combination thereof. Examples of the sulfonic acid type anionic surfactant include naphthalene sulfonic acid Na formalin condensate, polyoxyethylene sulfosuccinic acid alkyl 2Na, polystyrene sulfonic acid Na, dioctyl sulfosuccinic acid Na, polyoxyethylene lauryl ether sulfate triethanolamine. It is done. Examples of the sulfate ester type anionic surfactant include polyoxyethylene lauryl ether sulfate Na. The treatment of the porous substrate with the surfactant is not particularly limited as long as it is a technique capable of attaching the surfactant to the surface of the porous substrate, and a solution containing the surfactant is applied to the porous substrate. What is necessary is just to apply | coat or immerse a porous base material in the solution containing surfactant. The porous substrate may be immersed in the solution containing the surfactant while stirring the solution at room temperature or high temperature (for example, 40 to 80 ° C.), and the immersion time is not particularly limited, but for example, 1 to 7 days. is there.

(Ii) Chemical species that provide cations The starting point of LDH crystal growth can be a chemical species that provides cations that can be a component of the layered double hydroxide. A preferred example of such a cation is Al ³⁺ . In this case, the starting material is preferably at least one aluminum compound selected from the group consisting of aluminum oxides, hydroxides, oxyhydroxides, and hydroxy complexes. Therefore, the starting material that can provide such a starting point may be uniformly attached to the surface of the porous member by an appropriate method according to the type of the starting material. By imparting a chemical species that gives a cation to the surface, an anion that can enter between the layers of LDH can be adsorbed on the surface of the porous substrate to generate LDH nuclei. Therefore, by performing the subsequent step (c), a highly densified LDH film can be uniformly formed on the surface of the porous substrate without unevenness.

According to a preferred aspect of the present invention, the starting material can be attached by applying a sol containing an aluminum compound to the porous member. In this case, examples of preferred aluminum compounds include boehmite (AlOOH), aluminum hydroxide (Al (OH) ₃ ), and amorphous alumina, with boehmite being most preferred. The application of the sol containing the aluminum compound is preferably performed by spin coating because it can be applied uniformly. The spin coating conditions are not particularly limited. For example, the spin coating may be performed at a rotational speed of 1000 to 10000 rpm for about 60 to 300 seconds including dripping and drying.

According to another preferred embodiment of the present invention, the starting material is adhered by subjecting the porous substrate to hydrothermal treatment in an aqueous solution containing at least aluminum to form an aluminum compound on the surface of the porous substrate. be able to. The aluminum compound formed on the surface of the porous substrate is preferably Al (OH) ₃ . In particular, LDH films on porous substrates (especially ceramic porous substrates) tend to produce crystalline and / or amorphous Al (OH) _{3 in the} initial stage of growth. Can grow. Therefore, after the Al (OH) ₃ is uniformly attached to the surface of the porous substrate by hydrothermal treatment in advance, the step (c) that also involves hydrothermal treatment is performed, The LDH film can be uniformly formed without unevenness. In this embodiment, the step (b) and the subsequent step (c) may be performed continuously in the same sealed container, or the step (b) and the subsequent step (c) are performed separately in this order. May be.

When the step (b) and the step (c) are continuously performed in the same sealed container, the raw material aqueous solution (that is, the aqueous solution containing the constituent elements of LDH) used in the step (c) described later is used as it is in the step (b). Can be used. Even in this case, the hydrothermal treatment in the step (b) is compared with 50 to 70 ° C. in an acidic or neutral pH range (preferably pH 5.5 to 7.0) in an airtight container (preferably an autoclave). By performing in a low temperature region, not LDH but Al
(OH) ₃ nucleation can be promoted. In addition, after the nucleation of Al (OH) ₃ , the pH of the raw material aqueous solution rises due to the hydrolysis of urea by holding or raising the temperature at the nucleation temperature, and therefore a pH range suitable for LDH growth. It is possible to smoothly shift to step (c) at (preferably more than pH 7.0).

On the other hand, when the step (b) and the step (c) are separately performed in this order, it is preferable to use different raw material aqueous solutions in the step (b) and the step (c). For example, in step (b), it is preferable to nucleate Al (OH) ₃ using a raw material aqueous solution mainly containing an Al source (preferably not containing other metal elements). In this case, the hydrothermal treatment in the step (b) may be performed at 50 to 120 ° C. in a closed container (preferably an autoclave) different from the step (c). Preferable examples of the raw material aqueous solution mainly containing an Al source include an aqueous solution containing aluminum nitrate and urea and not containing a magnesium compound (for example, magnesium nitrate). By using a raw material aqueous solution not containing Mg, precipitation of LDH can be avoided and nucleation of Al (OH) ₃ can be promoted.

According to still another preferred embodiment of the present invention, the starting material is adhered by depositing aluminum on the surface of the porous substrate and then converting the aluminum into an aluminum compound by hydrothermal treatment in an aqueous solution. Can do. This aluminum compound is preferably Al
(OH) ₃ . In particular, by converting to Al (OH) ₃ , the growth of LDH can be promoted using this as a nucleus. Therefore, after the Al (OH) ₃ is uniformly formed on the surface of the porous base material by hydrothermal treatment, the same process (c) accompanied by hydrothermal treatment is carried out. A densified LDH film can be uniformly formed without unevenness. Aluminum may be deposited by physical vapor deposition or chemical vapor deposition, but physical vapor deposition such as vacuum vapor deposition is preferred. Moreover, the aqueous solution used for the hydrothermal treatment for aluminum conversion should just be a composition which can react with Al already provided by vapor deposition and can produce | generate Al (OH) _3, and is not specifically limited.

(Iii) LDH as a starting point
The starting point for crystal growth can be LDH. In this case, the growth of LDH can be promoted starting from the nucleus of LDH. Therefore, after the LDH nuclei are uniformly attached to the surface of the porous base material, the subsequent step (c) is performed to unevenly disperse the highly densified LDH film on the surface of the porous base material. And can be formed uniformly.

  According to a preferred aspect of the present invention, the starting material can be attached by applying a sol containing LDH to the surface of the porous member. The sol containing LDH may be prepared by dispersing LDH in a solvent such as water, and is not particularly limited. In this case, the application is preferably performed by spin coating. Spin coating is preferred because it can be applied very uniformly. The spin coating conditions are not particularly limited. For example, the spin coating may be performed at a rotational speed of 1000 to 10000 rpm for about 60 to 300 seconds including dripping and drying.

  According to another preferred embodiment of the present invention, the deposition of the starting material is performed by depositing aluminum (deposited) in an aqueous solution containing a constituent element of LDH other than aluminum after depositing aluminum on the surface of the porous substrate. It can be performed by converting to LDH by hydrothermal treatment. Aluminum may be deposited by physical vapor deposition or chemical vapor deposition, but physical vapor deposition such as vacuum vapor deposition is preferred. Moreover, the raw material aqueous solution used for the hydrothermal treatment for the conversion of aluminum may be performed using an aqueous solution containing a component other than Al already provided by vapor deposition. A preferable example of such a raw material aqueous solution is a raw material aqueous solution mainly containing a Mg source, and more preferably, an aqueous solution containing magnesium nitrate and urea and not containing an aluminum compound (aluminum nitrate). By including the Mg source, the nuclei of LDH can be formed together with Al already provided by vapor deposition.

(C) Hydrothermal treatment A hydrothermal treatment is performed on a porous substrate (a starting material can be attached if desired) in a raw material aqueous solution containing a constituent element of LDH to form an LDH film on the surface of the porous substrate. A preferable raw material aqueous solution contains magnesium ions (Mg ²⁺ ) and aluminum ions (Al ³⁺ ) at a predetermined total concentration, and contains urea. Due to the presence of urea, ammonia is generated in the solution by utilizing hydrolysis of urea, so that the pH value rises (for example, more than pH 7.0, preferably more than 7.0 and less than 8.5) and coexists. LDH can be obtained when metal ions form hydroxides. Further, since carbon dioxide is generated in the hydrolysis, LDH in which the anion is carbonate ion type can be obtained. The total concentration (Mg ²⁺ + Al ³⁺ ) of magnesium ions and aluminum ions contained in the raw material aqueous solution is preferably 0.20 to 0.40 mol / L, more preferably 0.22 to 0.38 mol / L, still more preferably 0.24 to 0.36 mol / L, particularly preferably 0.26 to 0.34 mol / L. When the concentration is within such a range, nucleation and crystal growth can proceed in a balanced manner, and an LDH film excellent not only in orientation but also in denseness can be obtained. That is, when the total concentration of magnesium ions and aluminum ions is low, crystal growth becomes dominant compared to nucleation, and the number of particles decreases and particle size increases. It is considered that the generation becomes dominant, the number of particles increases, and the particle size decreases.

Preferably, magnesium nitrate and aluminum nitrate are dissolved in the raw material aqueous solution, whereby the raw material aqueous solution contains nitrate ions in addition to magnesium ions and aluminum ions. In this case, the molar ratio (urea / NO ₃ ⁻ ) of urea to nitrate ions (NO ₃ ⁻ ) in the raw material aqueous solution is preferably 2 to 6, and more preferably 4 to 5.

  The porous substrate may be immersed in the raw material aqueous solution in a desired direction (for example, horizontally or vertically). When the porous substrate is held horizontally, the porous substrate may be suspended, floated, or disposed so as to be in contact with the bottom of the container. For example, the porous substrate is suspended from the bottom of the container in the raw material aqueous solution. The material may be fixed. When the porous substrate is held vertically, a jig that can set the porous substrate vertically on the bottom of the container may be placed. In any case, the LDH is perpendicular to or close to the porous substrate (that is, the LDH plate-like particles are such that their plate surfaces intersect the surface (substrate surface) of the porous substrate perpendicularly or obliquely. It is preferable to adopt a configuration or arrangement in which the growth is performed in any direction.

In the raw material aqueous solution, the porous substrate is subjected to hydrothermal treatment to form an LDH film on the surface of the porous substrate. This hydrothermal treatment is preferably carried out in a sealed container (preferably an autoclave) at 60 to 150 ° C., more preferably 65 to 120 ° C., further preferably 65 to 100 ° C., particularly preferably 70 to 90 ° C. The upper limit temperature of the hydrothermal treatment may be selected so that the porous substrate (for example, the polymer substrate) is not deformed by heat. The rate of temperature increase during the hydrothermal treatment is not particularly limited and may be, for example, 10 to 200 ° C./h, preferably 100 to 200 ° C./h, more preferably 100 to 150 ° C./h. The hydrothermal treatment time may be appropriately determined according to the target density and thickness of the LDH film.

  After the hydrothermal treatment, the porous substrate is preferably taken out from the sealed container and washed with ion exchange water.

  The LDH film produced as described above is one in which LDH plate-like particles are highly densified and are oriented in the vertical direction advantageous for conduction. That is, the LDH film typically does not have water permeability (desirably water permeability and air permeability) due to high density. Further, the LDH constituting the LDH film is composed of an aggregate of a plurality of plate-like particles, and the plurality of plate-like particles are oriented so that their plate surfaces perpendicularly or obliquely intersect the surface of the porous substrate. Typically, it is oriented in the direction. Accordingly, when an LDH film having sufficient gas tightness and a dense LDH film is used for a battery such as a zinc-air battery, an improvement in power generation performance can be expected, and a secondary battery for a zinc-air battery using an electrolyte that has not been conventionally applicable It is expected to be applied to new separators such as zinc dendrite progress barriers and carbon dioxide intrusion separators, which have become major barriers to chemical conversion. Similarly, it is expected to be applied to a nickel-zinc battery in which the progress of zinc dendrite is a major barrier to practical use.

  By the way, the LDH film obtained by the above production method can be formed on both surfaces of the porous substrate. For this reason, in order to make the LDH film suitable for use as a separator, the LDH film on one side of the porous substrate is mechanically scraped after film formation, or the LDH film is formed on one side during film formation. It is desirable to take measures that prevent film formation.

  The present invention is more specifically described by the following examples.

Examples 1 to 3 (Comparison): Nickel-zinc battery using a positive electrode having no opening Four Ni (OH) ₂ -containing positive plates each having a positive electrode 12 having the size shown in Table 1 were prepared. As this positive electrode plate, a commercially available sintered Ni (OH) ₂ -containing electrode plate was used. The thickness of the positive electrode 12 was 0.6 mm.

  On the other hand, four ZnO-containing negative electrode plates provided with the negative electrode 16 having the same size as the positive electrode 12 were prepared. This ZnO-containing negative electrode plate was prepared by applying a mixture of 80 parts by weight of zinc oxide powder, 20 parts by weight of zinc powder and 3 parts by weight of polytetrafluoroethylene particles on one surface of a negative electrode current collector 17 made of copper mesh. 16 was produced.

As schematically shown in FIG. 6, four positive plates (positive electrode 12 / positive electrode current collector 13 / positive electrode 12) were arranged in parallel with each other in a flexible resin container 22. Further, four negative plates (negative electrode 16 / negative electrode current collector 17) were arranged in parallel to each other at a position away from the positive electrode plate in the container 22. At this time, in order to improve liquid retention around each of the positive electrode plate and the negative electrode plate, each of the positive electrode plate and the negative electrode plate is entirely made of a nonwoven fabric 19 (product name: hydrophilic polyolefin, manufactured by Nippon Vilene Co., Ltd., material: polyolefin). Wrapped with a thickness of 0.1 mm). Further, the positive electrode plate and the negative electrode plate were reliably partitioned by a separator structure in which the outer periphery of the separator 20 with the porous substrate 28 (LDH dense film) was liquid-tightly sealed and joined to the resin frame 29. The separator layer 20 with the porous substrate 28 is produced according to the procedure of Example 21 described later. In the container 22, 6 M KOH aqueous solution was put as the positive electrode electrolyte 14 and the negative electrode electrolyte 18, and the positive electrode 12 and the negative electrode 16 were immersed in the electrolyte 15. This KOH aqueous solution is prepared by dissolving Al and Zn in advance. The positive electrode current collector 13 and the negative electrode current collector 17 were each connected to a terminal to enable charging / discharging. A flexible resin container 22 was sandwiched between the plates and pressurized at 0.35 MPa so that the four positive plates and the four negative plates were brought into close contact with each other through the nonwoven fabric. The nickel zinc battery assembled in this way was subjected to a charge / discharge test under the following conditions.
<Cycle conditions>
-Number of cycles: 1
-Mode: CC (constant current)
<Charging conditions>
-Current density: 25 mA / cm ²
-SOC (State of Charge): 100%
<Discharge conditions>
-Current density: 25 mA / cm ²
-Cut-off: 1.0V

Examples 4-8 : Nickel-zinc battery using a positive electrode with a round hole as an opening As in Example 1, a positive electrode plate was prepared so as to avoid iron punching metal holes (see, eg, FIGS. 5A and 5B) A nickel zinc battery was produced and evaluated in the same manner as in Example 1 except that the round holes (through holes) having the diameters and numbers shown in Table 1 were regularly formed with a drill. At this time, in Examples 4 to 6 and 8, the round holes were overlapped between adjacent positive plates, while in Example 7, the round holes were shifted without overlapping. The results were as shown in Table 1 and FIG.

  From the results shown in Table 1 and FIG. 12, it was found that by using the positive electrode provided with an opening, superior discharge characteristics were obtained as compared with the battery of Example 1 using the positive electrode having no opening. I understand. Further, from the comparison of Examples 6 and 7, even when the opening area ratio is the same, the case where the openings are shifted between the adjacent positive plates rather than the case where the openings are overlapped between the adjacent positive plates, It can also be seen that the discharge capacity is high.

Examples 9 to 20 : Nickel zinc battery using positive electrode having slits as openings A positive electrode was prepared in the same manner as in Examples 1 to 3 and punched for Examples 9 to 19 and punched for Example 20 in Table 1. A nickel zinc battery was fabricated and evaluated in the same manner as in Examples 1 to 3, except that the width, length, and number of through slits shown were formed. At this time, in Examples 9 to 13, 15 and 17 to 19, slits are overlapped between adjacent positive electrode plates, while in Examples 14, 16 and 20, the slits are shifted without overlapping between adjacent positive electrode layers. did. The results were as shown in Table 2 and FIG.

  From the results shown in Table 2 and FIG. 10, by using a positive electrode provided with an opening, superior discharge characteristics were obtained compared to the batteries of Examples 1 to 3 using a positive electrode having no opening. I understand that. In addition, from the comparison of Examples 13 and 14 and the comparison of Examples 15 and 16, even when the opening area ratio was the same, the openings were shifted between the adjacent positive electrode layers as compared with the case where the openings were overlapped between the adjacent positive electrode layers. It can also be seen that the discharge capacity is higher in the case.

Example 21 Production and Evaluation of LDH Separator with Porous Substrate (1) Production of Porous Substrate Boehmite (manufactured by Sasol, DISPAL 18N4-80), methylcellulose, and ion-exchanged water (boehmite): (methylcellulose) : (Ion-exchanged water) mass ratio was 10: 1: 5, and then kneaded. The obtained kneaded product was subjected to extrusion molding using a hand press and molded into a plate shape having a size sufficiently exceeding 5 cm × 8 cm and a thickness of 0.5 cm. The obtained molded body was dried at 80 ° C. for 12 hours and then calcined at 1150 ° C. for 3 hours to obtain an alumina porous substrate. The porous substrate thus obtained was cut into a size of 5 cm × 8 cm.

  With respect to the obtained porous substrate, the porosity on the surface of the porous substrate was measured by a technique using image processing, and it was 24.6%. The porosity was measured as follows. That is, 1) An electron microscope (SEM) image (magnification of the surface of a porous substrate) was observed with a scanning electron microscope (SEM, JSM-6610LV, manufactured by JEOL) at an acceleration voltage of 10 to 20 kV. 10,000 times or more). 2) A gray scale SEM image was read using image analysis software such as Photoshop (manufactured by Adobe). 3) A black and white binary image was created by the procedure of [Image] → [Tone Correction] → [Turn Tone]. 4) The porosity (%) was obtained by dividing the number of pixels occupied by the black portion by the total number of pixels in the image. This porosity measurement was performed on a 6 μm × 6 μm region on the surface of the porous substrate. FIG. 11 shows an SEM image of the porous substrate surface.

  Moreover, it was about 0.1 micrometer when the average hole diameter of the porous base material was measured. In the present invention, the average pore diameter was measured by measuring the longest distance of the pores based on an electron microscope (SEM) image of the surface of the porous substrate. The magnification of the electron microscope (SEM) image used for this measurement is 20000 times, and all the obtained pore diameters are arranged in order of size, and the top 15 points and the bottom 15 points from the average value, and 30 points per visual field in total. The average value for two visual fields was calculated to obtain the average pore diameter. For length measurement, the length measurement function of SEM software was used.

(2) Cleaning of porous substrate The obtained porous substrate was ultrasonically cleaned in acetone for 5 minutes, ultrasonically cleaned in ethanol for 2 minutes, and then ultrasonically cleaned in ion-exchanged water for 1 minute.

(3) As the manufacturing raw material of the raw aqueous solution, magnesium nitrate hexahydrate _{(Mg (NO 3) 2 ·} 6H 2 O, manufactured by Kanto Chemical Co., Inc.), aluminum nitrate nonahydrate (Al _{(NO 3)} 3 · 9H ₂ O, manufactured by Kanto Chemical Co., Ltd.) and urea ((NH ₂ ) ₂ CO, manufactured by Sigma-Aldrich) were prepared. Weigh magnesium nitrate hexahydrate and aluminum nitrate nonahydrate so that the cation ratio (Mg ²⁺ / Al ³⁺ ) is 2 and the total metal ion molar concentration (Mg ²⁺ + Al ³⁺ ) is 0.320 mol / L. In a beaker, ion exchange water was added to make a total volume of 600 ml. After stirring the obtained solution, urea weighed at a ratio of urea / NO ₃ ⁻ = 4 was added to the solution, and further stirred to obtain a raw material aqueous solution.

(4) Film formation by hydrothermal treatment The Teflon (registered trademark) sealed container (with an internal volume of 800 ml, the outside is a stainless steel jacket), the raw material aqueous solution prepared in (3) above and the porous substrate washed in (2) above Both were enclosed. At this time, the base material was fixed by being floated from the bottom of a Teflon (registered trademark) sealed container, and placed horizontally so that the solution was in contact with both surfaces of the base material. Thereafter, hydrothermal treatment was performed at a hydrothermal temperature of 70 ° C. for 168 hours (7 days) to form a layered double hydroxide alignment film (separator layer) on the substrate surface. After the elapse of a predetermined time, the substrate is taken out from the sealed container, washed with ion-exchanged water, dried at 70 ° C. for 10 hours, and a dense layer of layered double hydroxide (hereinafter referred to as LDH) (hereinafter referred to as a membrane sample). ) Was obtained on a substrate. The thickness of the obtained film sample was about 1.5 μm. Thus, a layered double hydroxide-containing composite material sample (hereinafter referred to as a composite material sample) was obtained. Although the LDH film was formed on both surfaces of the porous substrate, the LDH film on one surface of the porous substrate was mechanically scraped to give the composite material a form as a separator.

(5) Various evaluations (5a) Identification of film sample Film sample with X-ray diffractometer (RINT TTR III manufactured by Rigaku Corporation) under the measurement conditions of voltage: 50 kV, current value: 300 mA, measurement range: 10-70 ° As a result, the XRD profile shown in FIG. 12 was obtained. About the obtained XRD profile, JCPDS card NO. It identified using the diffraction peak of the layered double hydroxide (hydrotalcite compound) described in 35-0964. As a result, it was confirmed that the film sample was a layered double hydroxide (LDH, hydrotalcite compound). In the XRD profile shown in FIG. 12, a peak (peak marked with a circle in the figure) due to alumina constituting the porous substrate on which the film sample is formed is also observed. .

(5b) Observation of microstructure The surface microstructure of the film sample was observed at an acceleration voltage of 10 to 20 kV using a scanning electron microscope (SEM, JSM-6610LV, manufactured by JEOL). FIG. 13 shows an SEM image (secondary electron image) of the surface microstructure of the obtained film sample.

  Further, the cross section of the composite material sample was polished by CP polishing to form a polished cross section, and the microstructure of the polished cross section was observed at an acceleration voltage of 10 to 20 kV using a scanning electron microscope (SEM). FIG. 14 shows an SEM image of the polished cross-sectional microstructure of the composite material sample thus obtained.

(5c) Measurement of porosity The porosity of the surface of the membrane was measured for the membrane sample by a technique using image processing. The porosity was measured as follows. That is, 1) The surface microstructure was observed with a scanning electron microscope (SEM, JSM-6610LV, manufactured by JEOL) at an acceleration voltage of 10 to 20 kV, and an electron microscope (SEM) image of the film surface (10000 × magnification) Obtained). 2) A gray scale SEM image was read using image analysis software such as Photoshop (manufactured by Adobe). 3) A black and white binary image was created by the procedure of [Image] → [Tone Correction] → [Turn Tone]. 4) The porosity (%) was obtained by dividing the number of pixels occupied by the black portion by the total number of pixels in the image. This porosity measurement was performed on a 6 μm × 6 μm region of the alignment film surface. As a result, the porosity of the film surface was 19.0%. Further, using the porosity of the film surface, the density D when viewed from the film surface (hereinafter referred to as the surface film density) was calculated by D = 100% − (porosity of the film surface). %Met.

  Further, the porosity of the polished cross section of the film sample was also measured. The measurement of the porosity of the polished cross section is the same as that described above except that an electron microscope (SEM) image (magnification of 10,000 times or more) of the cross-section polished surface in the thickness direction of the film was obtained according to the procedure shown in (5b) above. It carried out similarly to the porosity of the film | membrane surface. The measurement of the porosity was performed on the film portion of the alignment film cross section. Thus, the porosity calculated from the cross-sectional polished surface of the film sample is 3.5% on average (average value of the three cross-sectional polished surfaces), and a very high-density film is formed on the porous substrate. It was confirmed that

(5d) Denseness determination test A denseness determination test was performed as follows in order to confirm that the film sample has a denseness that does not have water permeability. First, as shown in FIG. 15A, the composite material sample 120 obtained in the above (1) (one cut into 1 cm × 1 cm square) has a 0.5 cm × 0.5 cm square at the center on the film sample side. The silicon rubber 122 provided with the opening 122a was adhered, and the obtained laminate was adhered between two acrylic containers 124 and 126. The bottom of the acrylic container 124 disposed on the silicon rubber 122 side is pulled out, whereby the silicon rubber 122 is bonded to the acrylic container 124 with the opening 122a open. On the other hand, the acrylic container 126 disposed on the porous substrate side of the composite material sample 120 has a bottom, and ion-exchanged water 128 is contained in the container 126. At this time, Al and / or Mg may be dissolved in the ion exchange water. That is, by assembling the components upside down after assembly, the constituent members are arranged so that the ion exchange water 128 is in contact with the porous substrate side of the composite material sample 120. After assembling these components, the total weight was measured. Needless to say, the container 126 has a closed vent hole (not shown) and is opened after being turned upside down. As shown in FIG. 15B, the assembly was placed upside down and held at 25 ° C. for 1 week, and then the total weight was measured again. At this time, when water droplets were attached to the inner side surface of the acrylic container 124, the water droplets were wiped off. Then, the density was determined by calculating the difference in the total weight before and after the test. As a result, no change was observed in the weight of ion-exchanged water even after holding at 25 ° C. for 1 week. From this, it was confirmed that the membrane sample (that is, the functional membrane) has high density so as not to have water permeability.

Example 22 (Reference): Preparation and Evaluation of Nickel Zinc Battery This example is a reference example in which a nickel zinc battery using an LDH separator with a porous substrate was prepared and evaluated. Although this example is not an example using an electrode with an opening, it is possible to produce a nickel-zinc battery according to the present invention by appropriately replacing the positive electrode or the negative electrode with an electrode with an opening of the present invention. Needless to say.

(1) Preparation of separator with porous substrate By the same procedure as Example 21, an LDH film on an alumina substrate (size: 5 cm x 8 cm) was prepared as a separator with a porous substrate.

(2) Preparation of positive electrode plate Nickel hydroxide particles to which zinc and cobalt were added so as to form a solid solution were prepared. The nickel hydroxide particles were coated with cobalt hydroxide to obtain a positive electrode active material. The obtained positive electrode active material was mixed with a 2% aqueous solution of carboxymethyl cellulose to prepare a paste. The paste obtained above is uniformly applied to a current collector made of a nickel metal porous substrate having a porosity of about 95% and dried so that the porosity of the positive electrode active material is 50%. A positive electrode plate coated over an area of 5 cm × 5 cm was obtained. At this time, the coating amount was adjusted so that nickel hydroxide particles corresponding to 4 Ah were included in the active material.

(3) Production of negative electrode plate A mixture of 80 parts by weight of zinc oxide powder, 20 parts by weight of zinc powder and 3 parts by weight of polytetrafluoroethylene particles was applied on a current collector made of copper punching metal, and the porosity was about A negative electrode plate was obtained in which the active material portion was coated over an area of 5 cm × 5 cm at 50%. At this time, the coating amount was adjusted so that the zinc oxide powder corresponding to the positive electrode plate capacity of 4 Ah was included in the active material.

(4) Battery assembly Using the positive electrode plate, the negative electrode plate, and the separator with the porous substrate obtained above, a nickel zinc battery was assembled in the following procedure.

  First, a rectangular parallelepiped case main body made of ABS resin from which the case upper lid was removed was prepared. A separator with a porous base material (LDH film on alumina base material) is inserted near the center of the case body so that the porous base material is located on the positive electrode chamber side and the separator is located on the negative electrode chamber side. Was fixed to the inner wall of the case body using a commercially available adhesive. The positive electrode plate and the negative electrode plate were inserted into the positive electrode chamber and the negative electrode chamber, respectively. At this time, the positive electrode plate and the negative electrode plate were arranged so that the positive electrode current collector and the negative electrode current collector were in contact with the inner wall of the case body. A 6 mol / L aqueous KOH solution in an amount that sufficiently hides the positive electrode active material coating portion was injected into the positive electrode chamber as an electrolyte. On the other hand, in the negative electrode chamber, not only the negative electrode active material coating part was sufficiently hidden, but also an excessive amount of 6 mol / L KOH aqueous solution was injected as an electrolyte considering the amount of water expected to decrease during charging. . The terminal portions of the positive electrode current collector and the negative electrode current collector were connected to external terminals at the top of the case. The case upper lid was fixed to the case body by heat sealing, and the battery case container was sealed. Thus, a nickel zinc battery was obtained. In this battery, since the size of the separator is 5 cm wide × 8 cm high, and the size of the active material coated portion of the positive electrode plate and the negative electrode plate is 5 cm wide × 5 cm high, the positive electrode chamber and the negative electrode The space equivalent to 3 cm above the chamber can be said to be the positive electrode side excess space and the negative electrode side excess space.

(5) Evaluation The manufactured nickel zinc battery was subjected to constant current charging for 10 hours at a current of 0.4 mA corresponding to 0.1 C with a design capacity of 4 Ah. After charging, no deformation of the case or leakage of the electrolyte was observed. Although the positive electrode chamber electrolyte increased and the negative electrode chamber electrolyte decreased due to charging, there was sufficient electrolyte in the negative electrode active material coating part, and the applied positive electrode active material and negative electrode active material were charged and discharged. The electrolyte that causes a sufficient charge / discharge reaction could be held in the case.

Example 23 : Production and Evaluation of LDH Separator with Porous Base Material In this example, an LDH-containing composite material sample (separator sample with a porous base material) in which a layered double hydroxide (LDH) dense film was formed on the porous base material. Samples 1 to 10 were prepared as follows.

(1) Production of porous substrate Boehmite (manufactured by Sasol, DISPAL 18N4-80), methylcellulose, and ion-exchanged water are mixed at a weight ratio of 10: 1: (boehmite) :( methylcellulose) :( ion-exchanged water). After weighing so as to be 5, kneaded. The obtained kneaded product was subjected to extrusion molding using a hand press and molded into a size of 2.5 cm × 10 cm × thickness 0.5 cm. The obtained molded body was dried at 80 ° C. for 12 hours and then calcined at 1150 ° C. for 3 hours to obtain an alumina porous substrate.

  With respect to the obtained porous substrate, the porosity on the surface of the porous substrate was measured by a technique using image processing, and it was 24.6%. The porosity was measured as follows. That is, 1) An electron microscope (SEM) image (magnification of the surface of a porous substrate) was observed with a scanning electron microscope (SEM, JSM-6610LV, manufactured by JEOL) at an acceleration voltage of 10 to 20 kV. 10,000 times or more). 2) A gray scale SEM image was read using image analysis software such as Photoshop (manufactured by Adobe). 3) A black and white binary image was created by the procedure of [Image] → [Tone Correction] → [Turn Tone]. 4) The porosity (%) was obtained by dividing the number of pixels occupied by the black portion by the total number of pixels in the image. This porosity measurement was performed on a 6 μm × 6 μm region on the surface of the porous substrate.

  Moreover, it was about 0.1 micrometer when the average hole diameter of the porous base material was measured. In the present invention, the average pore diameter was measured by measuring the longest distance of the pores based on an electron microscope (SEM) image of the surface of the porous substrate. The magnification of the electron microscope (SEM) image used for this measurement is 20000 times, and all the obtained pore diameters are arranged in order of size, and the top 15 points and the bottom 15 points from the average value, and 30 points per visual field in total. The average value for two visual fields was calculated to obtain the average pore diameter. For length measurement, the length measurement function of SEM software was used.

(2) Cleaning of porous substrate The obtained porous substrate was ultrasonically cleaned in acetone for 5 minutes, ultrasonically cleaned in ethanol for 2 minutes, and then ultrasonically cleaned in ion-exchanged water for 1 minute.

(3) Polystyrene spin coating and sulfonation For samples 1 to 6 only, polystyrene spin coating and sulfonation were performed on the porous substrate by the following procedure. That is, 0.6 g of a polystyrene substrate was dissolved in 10 ml of a xylene solution to prepare a spin coating solution having a polystyrene concentration of 0.06 g / ml. 0.1 ml of the obtained spin coating solution was dropped onto the porous substrate and applied by spin coating at a rotation speed of 8000 rpm. This spin coating was performed for 200 seconds including dripping and drying. The porous substrate coated with the spin coating solution was immersed in 95% sulfuric acid at 25 ° C. for 4 days for sulfonation.

(4) As the manufacturing raw material of the raw aqueous solution, magnesium nitrate hexahydrate _{(Mg (NO 3) 2 ·} 6H 2 O, manufactured by Kanto Chemical Co., Inc.), aluminum nitrate nonahydrate _{(Al (NO 3) 3 ·} 9H ₂ O, manufactured by Kanto Chemical Co., Ltd.) and urea ((NH ₂ ) ₂ CO, manufactured by Sigma-Aldrich) were prepared. Weigh magnesium nitrate hexahydrate and aluminum nitrate nonahydrate so that the cation ratio (Mg ²⁺ / Al ³⁺ ) is 2 and the total metal ion molar concentration (Mg ²⁺ + Al ³⁺ ) is 0.320 mol / L. In a beaker, ion exchange water was added to make a total volume of 75 ml. After stirring the obtained solution, urea weighed at a ratio of urea / NO ₃ ⁻ = 4 was added to the solution, and further stirred to obtain a raw material aqueous solution.

(5) Film formation by hydrothermal treatment A Teflon (registered trademark) sealed container (with an internal volume of 100 ml, the outside is a stainless steel jacket) and the raw material aqueous solution prepared in (4) above and the porous substrate sulfonated in (3) above (Samples 1 to 6) or the porous substrate (samples 7 to 10) washed in (2) above was enclosed together. At this time, the base material was fixed by being floated from the bottom of a Teflon (registered trademark) sealed container, and placed horizontally so that the solution was in contact with both surfaces of the base material. Then, the layered double hydroxide alignment film was formed on the substrate surface by performing hydrothermal treatment at a hydrothermal temperature of 70 to 75 ° C. for 168 to 504 hours. At this time, ten kinds of alignment films having various denseness were produced by appropriately changing the conditions of the hydrothermal treatment. After the elapse of a predetermined time, the substrate is taken out from the sealed container, washed with ion-exchanged water, dried at 70 ° C. for 10 hours, and a dense layer of layered double hydroxide (hereinafter referred to as LDH) (hereinafter referred to as a membrane sample). ) Was obtained on a substrate. The thickness of the obtained film sample was about 1.0 to 2.0 μm. Thus, Samples 1 to 10 were obtained as LDH-containing composite material samples (hereinafter referred to as composite material samples). In addition, although the LDH film was formed on both surfaces of the porous substrate, the LDH film on one surface of the porous substrate was mechanically scraped to give the composite material a form as a separator.

(6a) Identification of membrane sample Using an X-ray diffractometer (RINT TTR III manufactured by Rigaku Corporation), the crystal phase of the membrane sample is measured under the measurement conditions of voltage: 50 kV, current value: 300 mA, measurement range: 10 to 70 °. To obtain an XRD profile. About the obtained XRD profile, JCPDS card NO. Identification was performed using a diffraction peak of a layered double hydroxide (hydrotalcite compound) described in 35-0964. As a result, it was confirmed that each of the film samples 1 to 10 was a layered double hydroxide (LDH, hydrotalcite compound).

(6b) He permeation measurement A He permeation test was performed as follows to evaluate the denseness of the membrane samples 1 to 10 from the viewpoint of He permeability. First, the He transmittance measurement system 310 shown in FIGS. 16A and 16B was constructed. In the He permeability measurement system 310, He gas from a gas cylinder filled with He gas is supplied to a sample holder 316 via a pressure gauge 312 and a flow meter 314 (digital flow meter), and the denseness held in the sample holder 316 is measured. The membrane 318 is configured to be transmitted through one surface from the other surface and discharged.

  The sample holder 316 has a structure including a gas supply port 316a, a sealed space 316b, and a gas discharge port 316c, and was assembled as follows. First, an adhesive 322 was applied along the outer periphery of the dense film 318 and attached to a jig 324 (made of ABS resin) having an opening at the center. Support members 328a and 328b (made of PTFE) provided with packings made of butyl rubber as sealing members 326a and 326b at the upper and lower ends of the jig 324 and further provided with openings formed of flanges from the outside of the sealing members 326a and 326b. ). Thus, the sealed space 316b was defined by the dense film 318, the jig 324, the sealing member 326a, and the support member 328a. The dense film 318 is in the form of a composite material formed on the porous substrate 320, but the dense film 318 is disposed so that the dense film 318 side faces the gas supply port 316a. The support members 328a and 328b were firmly fastened to each other by fastening means 330 using screws so that He gas leakage did not occur from a portion other than the gas discharge port 316c. A gas supply pipe 334 was connected to the gas supply port 316 a of the sample holder 316 assembled in this way via a joint 332.

Next, He gas was supplied to the He permeability measurement system 310 through the gas supply pipe 334 and permeated through the dense film 318 held in the sample holder 316. At this time, the gas supply pressure and the flow rate were monitored by the pressure gauge 312 and the flow meter 314. After permeating He gas for 1 to 30 minutes, the He permeability was calculated. The calculation of the He permeability is based on the permeation amount F (cm ³ / min) of He gas per unit time, the differential pressure P (atm) applied to the dense film during He gas permeation, and the membrane area S (cm ² ) and calculated by the formula of F / (P × S). The permeation amount F (cm ³ / min) of He gas was directly read from the flow meter 314. Further, as the differential pressure P, the gauge pressure read from the pressure gauge 312 was used. The He gas was supplied so that the differential pressure P was in the range of 0.05 to 0.90 atm. The obtained results were as shown in Table 1 and FIG.

(6c) Zn permeation test In order to evaluate the denseness of the film samples 1 to 10 from the viewpoint of Zn permeation, a Zn permeation test was performed as follows. First, a Zn transmission measuring device 340 shown in FIGS. 17A and 17B was constructed. The Zn transmission measuring device 340 includes a flanged open tube (made of PTFE) in which a flange 362a is integrated with a first tank 344 configured with an L-shaped open tube, and a second configured with an L-shaped tube. A flanged opening pipe (made of PTFE) in which a flange 362b is integrated with the tank 346 is arranged so that the flanges 362a and 362b face each other. Then, the sample holder 342 is disposed between the flanges 362a and 362b, and Zn can permeate from one surface of the dense film held by the sample holder 342 to the other surface.

  The assembly of the sample holder 342 and its attachment to the apparatus 340 were performed as follows. First, an adhesive 356 was applied along the outer periphery of the dense film 352 and attached to a jig 358 (made of ABS resin) having an opening at the center. As shown in FIG. 17A, silicone rubber packing is disposed on both sides of the jig 358 as sealing members 360a and 360b, and a pair of flanged opening pipe flanges 362a from the outside of the sealing members 360a and 360b. , 362b. The dense film 352 is in the form of a composite material formed on the porous substrate 354, but the dense tank 352 side (the first aqueous solution 348 containing Zn is injected) is the first tank 344. It was arranged to face. The flanges 362a and 362b were firmly tightened to each other by fastening means 364 using screws so that no liquid leakage occurred between them.

On the other hand, a 9 mol / L aqueous KOH solution in which 2.5 mol / L of Al (OH) ₃ and 0.5 mol / L of ZnO were dissolved was prepared as the first aqueous solution 348 to be put in the first tank 344. When the Zn concentration C ₁ (mol / L) of the first aqueous solution was measured by ICP emission spectroscopy, it was a value shown in Table 1. Further, as the second aqueous solution 350 to be put in the second tank 346, a 9 mol / L KOH aqueous solution in which 2.5 mol / L of Al (OH) ₃ was dissolved was prepared without dissolving ZnO. In the measurement apparatus 340 in which the sample holder 342 previously fabricated is incorporated, the first aqueous solution 348 and the second aqueous solution 350 are injected into the first tank 344 and the second tank 346, respectively, and the densely held by the sample holder 342 is obtained. Zn was permeated through the film 352. In this state, Zn permeation was performed at time t shown in Table 1, and then the liquid volume V ₂ (ml) of the second aqueous solution was measured, and the Zn concentration C ₂ (mol / L) of the second aqueous solution 350 was determined. It was measured by ICP emission spectroscopy. The Zn permeation ratio was calculated using the obtained value. The Zn transmission ratio was calculated by the formula (C ₂ × V ₂ ) / (C ₁ × V ₁ × t × S). In the formula, Zn concentration C ₁ (mol / L) of the first aqueous solution before the start of Zn permeation, the amount V ₁ (ml) of the first aqueous solution before the start of Zn permeation, and the second aqueous solution after the end of Zn permeation Zn concentration C ₂ (mol / L), liquid volume V ₂ (ml) of the second aqueous solution after completion of Zn permeation, Zn permeation time t (min), and film area S (cm ² ) through which Zn permeates Was used. The obtained results were as shown in Table 3 and FIG.

2, 2 ′, 2 ″, 2 ′ ″, 2 ″ ″ Electrode 4 Electrode layer 6 Opening (round hole)
6 'opening (slit)
DESCRIPTION OF SYMBOLS 8 Current collector 10 Nickel zinc battery 11 Positive electrode laminated body 12 Positive electrode 13 Positive electrode current collector 14 Positive electrode electrolyte 16 Negative electrode 17 Negative electrode current collector 18 Negative electrode electrolyte 19 Nonwoven fabric 20 Separator 22 Sealed container 24 Positive electrode chamber 26 Negative electrode chamber 28 Porous Base material 29 Resin frame

Claims (16)

An electrode used as a positive electrode or a negative electrode in a nickel zinc battery,
The electrode includes an electrode layer that is a positive electrode or a negative electrode,
The electrode, wherein the electrode layer is provided with an opening on at least one surface of the electrode layer for promoting the penetration of the electrolytic solution into the electrode.   The electrode according to claim 1, wherein the electrode layer has a thickness of 500 μm or more.   The electrode according to claim 1, wherein the electrode is a positive electrode, and the electrode layer includes at least one of nickel hydroxide and nickel oxyhydroxide.   The electrode according to claim 1, wherein the electrode is a negative electrode, and the electrode layer contains at least one of zinc and zinc oxide.   The ratio of the area of the opening to the total area of the electrode layer and the opening on the at least one surface of the electrode layer is 0.5 to 15%. Electrode.   5. The ratio of the area of the opening to the total area of the electrode layer and the opening on the at least one surface of the electrode layer is 1 to 10%. The electrode as described.   The electrode according to claim 1, wherein the opening has a geometric shape.   The electrode according to claim 1, wherein the opening penetrates the electrode layer.   The electrode according to claim 8, wherein the opening includes at least one of a through hole and a through slit.   An electrode assembly comprising two or more electrodes according to any one of claims 1 to 9, wherein the two or more electrodes are arranged in parallel to each other.   The electrode assembly according to claim 10, wherein the positions of the openings are different between the adjacent electrodes. A positive electrode comprising nickel hydroxide and / or nickel oxyhydroxide,
A positive electrode electrolyte solution containing an alkali metal hydroxide aqueous solution in which the positive electrode is immersed;
A negative electrode comprising zinc and / or zinc oxide;
A negative electrode electrolyte solution containing an alkali metal hydroxide aqueous solution in which the negative electrode is immersed;
A sealed container containing the positive electrode, the positive electrode electrolyte, the negative electrode, and the negative electrode electrolyte;
In the sealed container, provided to partition the positive electrode chamber containing the positive electrode and the positive electrode electrolyte and the negative electrode chamber containing the negative electrode and the negative electrode electrolyte, and has hydroxide ion conductivity. A ceramic separator made of an inorganic solid electrolyte body;
A nickel zinc battery in which at least one of the positive electrode and the negative electrode is the electrode according to any one of claims 1 to 9 or the electrode assembly according to claim 10 or 11.   The nickel zinc battery according to claim 12, wherein the inorganic solid electrolyte body is composed of a layered double hydroxide.   The separator is further provided with a porous substrate on one side or both sides thereof, and the inorganic solid electrolyte is in the form of a film or a layer, and the membrane or layer of the inorganic solid electrolyte is on the porous substrate or The nickel zinc battery according to claim 12 or 13, which is formed therein.   The layered double hydroxide is composed of an aggregate of a plurality of plate-like particles, and the plurality of plate-like particles are oriented so that their plate surfaces intersect perpendicularly or obliquely with the surface of the porous substrate. The nickel zinc battery according to claim 13 or 14, wherein the nickel zinc battery is oriented. The nickel-zinc battery according to any one of claims 13 to 15, wherein the separator has a He permeability per unit area of 10 cm / min · atm or less.