JP2022019898A - Electrode for primary battery or secondary battery with controlled local battery reaction and primary battery or secondary battery using the electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode for a secondary battery capable of suppressing the memory effect, improving the durability, and improving the capacity.

SOLUTION: In an electrode for a primary battery or a secondary battery including an electrode current collector and an electrode active material layer containing an electrode active material, the electrode current collector (especially when a circuit is open) is composed of a substance that controls a local battery reaction that occurs between the electrode current collector and the electrode active material or includes, on the surface, a layer that is made of a substance that controls a local battery reaction that occurs between the electrode current collector and the electrode active material. In particular, it is preferable that the electrode current collector does not include a substance having an electrode potential larger than that of the electrode active material on the surface.

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to an electrode for a primary battery or a secondary battery in which a local battery reaction is controlled, and a primary battery or a secondary battery using the electrode.

Alkaline secondary batteries such as nickel-metal hydride batteries and nickel-cadmium batteries have features such as high capacity, excellent discharge characteristics at high power and high current, and high safety, and are hybrid from household batteries. Widely used in various fields including cars. In particular, the energy density of nickel-metal hydride batteries is higher than that of nickel-cadmium batteries and lead-acid batteries, and the environmental load is small and the safety is high, so that they are particularly used in hybrid cars and the like.

For example, taking a nickel-metal hydride battery as an example, nickel hydroxide (Ni (OH) ₂ ) is used for the positive electrode, hydrogen storage alloy (MH: M stands for alloy) is used for the negative electrode, and potassium hydroxide aqueous solution (KOH (aq)) is used as the electrolytic solution. )) Etc., the reaction formula at the time of charging and discharging is expressed as follows.

Positive electrode: NiOOH + H ₂ O + e ^－ ⇔ Ni (OH) ₂ + OH ^－
Negative electrode: MH + OH ^－ ⇔ M + H ₂ O + e ^－
However, if the alkaline secondary battery is recharged before it is fully discharged, a phenomenon in which the electromotive force is significantly reduced before it is fully discharged, that is, the so-called memory effect, occurs when the battery is subsequently discharged. As a result, it seems that the capacity has decreased.

Conventionally, when a memory effect occurs, a method of forcibly discharging it deeply and then charging it again to eliminate the memory effect has been widely adopted.

However, this method does not suppress the occurrence of the memory effect, so it cannot be said to be a drastic solution. In addition, it takes wasted time and electricity to discharge deeply, and it is difficult to completely recover the capacity, so it cannot be said that the capacity and durability are sufficient. Moreover, such specialized operations have been one of the factors that hinder the spread of batteries. It is considered that such an adverse effect is seen not only in the secondary battery but also in the primary battery.

Various studies have been conducted on this memory effect so far, and according to Sato et al., The cause is that in nickel-metal hydride batteries, Ni (OH) ₂ is usually β-NiOOH in the charging process, and in the positive electrode. However, it is said that γ-NiOOH is generated by repeating shallow charging and discharging (Non-Patent Document 1). On the other hand, it is stated in the battery service column that γ-NiOOH is generated by overcharging and is more oxidized than β-NiOOH (Battery Handbook, 3rd edition, published on February 20, 2001, Maruzen Co., Ltd.). ).

Yuichi Sato et al., J. Power Sources 93 (2001) 20-24.

An object of the present invention is to provide an electrode for a primary battery or a secondary battery capable of suppressing the memory effect, improving the durability, and improving the capacity.

Conventionally, as described above, it was thought that γ-NiOOH was generated from β-NiOOH by repeating shallow charging and discharging, which deteriorated the battery, but the discharging was stopped in the middle of the discharging process, which is the reduction process. There is a contradiction as to why the memory effect sometimes occurs. Therefore, in view of the above problems, the present inventors have conducted detailed studies on the production of γ-NiOOH in batteries using β-NiOOH as an active material, such as nickel-metal hydride batteries and nickel-cadmium batteries. As a result, in batteries such as nickel hydrogen batteries and nickel cadmium batteries that use nickel hydroxide as an active material, a nickel mesh or the like is usually used as an electrode current collector, and β-NiOOH present on the positive electrode after discharge with this nickel. When the circuit is open, a local battery having an electrode active material (β-NiOOH) as a positive electrode and an electrode current collector (Ni) as a negative electrode is formed between the two, and the local battery reaction caused by the local battery reaction is referred to in Non-Patent Document 1. It was found that γ-NiOOH was generated and the battery was deteriorated.

The γ-NiOOH generated by the local battery reaction has a diffraction peak at a position of 10.5 to 15 degrees (particularly around 12 degrees) of the diffraction angle 2θ by X-ray diffraction with CuKα rays. On the other hand, γ-NiOOH generated by overcharging also has a diffraction peak at a position of 10.5 to 15 degrees (especially around 12 degrees) of the diffraction angle 2θ, and the peak positions are similar, but are they the same substance? It's not clear. This is because the charging process is an oxidation process for the electrode active material (β-NiOOH), whereas the process in which a local battery reaction occurs with the electrode current collector (Ni) is the electrode active material (β). -NiOOH) is a reduction process. In the present specification, γ-NiOOH generated by overcharging may be referred to as “γox-NiOOH”, and γ-NiOOH generated by a local battery reaction may be referred to as “γred-NiOOH”. In this notation, γ-NiOOH in Non-Patent Document 1 is γred-NiOOH. In addition, as described in the battery service column p.306-307 (Battery Handbook, 3rd edition, issued on February 20, 2001, Maruzen Co., Ltd.), it appears as a state of being more oxidized than β-NiOOH, which appears due to overcharging. Γ-NiOOH corresponds to γox-NiOOH. However, at this time, there is no report stating that γox-NiOOH and γred-NiOOH are materially different. Therefore, in the present specification, the two are referred to as γ-NiOOH without distinguishing between them, but in order to distinguish between the state in which oxidation has progressed and the state in which reduction has progressed, γox-in the subsequent parentheses. NiOOH or γred-NiOOH may also be described.

Generally, when the battery electrode is opened, a local battery reaction occurs between the electrode material and the electrode supporting metal. In particular, when the battery is not used, the circuit is opened and the above-mentioned local battery reaction occurs. By appropriately selecting the electrode support metal, the local battery reaction at the time of opening the circuit can be controlled. This time, by not including a substance having a base potential larger than that of the electrode active material on the surface of the electrode current collector, γ-NiOOH (γred-NiOOH) due to such a local battery reaction is produced. We found that we could control the generation. In this way, by changing the substance constituting the electrode, the local battery reaction can be controlled and the memory effect can be suppressed. Further, by controlling the local battery reaction, durability and capacity can be improved. These things are not limited to alkaline secondary batteries such as nickel hydrogen batteries and nickel cadmium batteries, which have a remarkable memory effect, but also secondary batteries such as lithium batteries and lead storage batteries, and primary batteries when local battery reactions occur. Since it is possible, the same improvement will be made. The present inventors further studied and completed the present invention. That is, the present invention includes the following configurations.
Item 1. A battery electrode including an electrode current collector and an electrode active material layer containing an electrode active material.
The electrode current collector is composed of a material that controls a local battery reaction that occurs between the electrode collector and the electrode active material, or occurs between the electrode collector and the electrode active material. An electrode for a primary battery or a secondary battery having a layer made of a substance that controls a local battery reaction on the surface.
Item 2. Item 2. The electrode according to Item 1, which is an electrode for a secondary battery.
Item 3. Item 2. The electrode according to Item 1 or 2, wherein the substance that controls the local battery reaction is a substance that controls the local battery reaction at the time of opening the circuit.
Item 4. Item 2. The electrode according to any one of Items 1 to 3, wherein the local battery reaction is the same reaction as the electrode reaction when the battery is used.
Item 5. Item 2. The electrode according to any one of Items 1 to 4, wherein the electrode current collector does not contain a substance having a base potential larger than that of the electrode active material on the surface.
Item 6. Item 5. The electrode according to Item 5, wherein the substance having a large and low electrode potential is a substance having a potential equal to or lower than −0.75 V as compared with the electrode active material.
Item 7. Item 2. The electrode according to any one of Items 1 to 6, wherein the substance that controls the local battery reaction is a substance having an electrode potential that is larger than that of the electrode active material and is not base.
Item 8. Item 7. The electrode according to Item 7, wherein the substance having a large and non-basic electrode potential is a substance having a potential higher than −0.75 V as compared with the electrode active material.
Item 9. Item 2. The electrode according to any one of Items 1 to 8, wherein the substance that controls the local battery reaction is a substance that is electrochemically inactive with respect to the electrolyte.
Item 10. Items 1 to 9 in which the electrode active material contains at least one selected from the group consisting of nickel hydroxide, β-NiOOH, lithium-containing transition metal oxide, lithium metal, carbonaceous material, lead oxide, and manganese dioxide. The electrode described in any of.
Item 11. Item 2. The electrode according to any one of Items 1 to 10, wherein the electrode active material contains nickel hydroxide and / or β-NiOOH.
Item 12. Item 6. The item 7. electrode.
Item 13. Item 9. The electrode according to any one of Items 9 to 11, wherein the substance electrochemically inert to the electrolyte contains at least one selected from the group consisting of a carbonaceous material and a conductive polymer.
Item 14. A primary battery or a secondary battery provided with the electrode according to any one of Items 1 to 13.
Item 15. Item 12. The battery according to Item 14, which is a secondary battery.
Item 16. Item 12. The battery according to Item 14 or 15, which is a nickel hydrogen battery, a nickel cadmium battery, a rechargeable alkaline battery, a lithium ion secondary battery or a lead storage battery.
Item 17. Item 6. The battery according to any one of Items 14 to 16, which is a nickel hydrogen battery or a nickel cadmium battery.
Item 18. Item 17. The secondary battery according to Item 17, wherein the electrode active material is suppressed from exhibiting a new diffraction peak at a position of 10.5 to 15 degrees of a diffraction angle 2θ by X-ray diffraction with CuKα rays.

According to the present invention, it is composed of a material that controls the local battery reaction that occurs between the electrode collector and the electrode active material, or controls the local battery reaction that occurs between the electrode collector and the electrode active material. An electrode current collector having a layer made of a substance (specifically, for example, the surface of the electrode current collector does not contain a substance having a lower electrode potential larger than that of the electrode active material). By using it, it is possible to control such a local battery reaction and improve the durability and capacity of the primary battery or the secondary battery. The fact that it does not contain a substance having an electrode potential larger than that of the electrode active material also includes a substance that is electrochemically inactive with respect to the electrolyte. When the electrode active material layer contains a conductive auxiliary agent, the local battery reaction that occurs between the material on the surface of the electrode current collector and the conductive auxiliary material and the electrode active material is controlled (electrode current collection). By not containing a substance having an electrode potential larger than that of the electrode active material on the surface of the body and the conductive auxiliary material), such a local battery reaction can be controlled, and the durability of the primary battery or the secondary battery can be controlled. The sex and capacity can be improved. In this case as well, the fact that the substance having a base potential larger than that of the electrode active material is not contained includes the substance that is electrochemically inactive with respect to the electrolyte. In particular, when β-NiOOH is used as an electrode active material, it is possible to suppress the production of γ-NiOOH (γred-NiOOH), which has been conventionally regarded as one of the causes of the memory effect. The memory effect can be suppressed by controlling the local battery reaction. Further, by controlling the local battery reaction, durability and capacity can be improved. This is because local battery reactions are considered to occur not only in alkaline secondary batteries such as nickel hydrogen batteries and nickel cadmium batteries, which have a remarkable memory effect, but also in lithium batteries, lead storage batteries, and various primary batteries. Similar improvements will be made.

It is a graph which shows the result of the X-ray diffraction of β-NiOOH synthesized in synthesis example 1. FIG. It is a graph of the result of X-ray diffraction which shows that γ-NiOOH (γox-NiOOH) is generated when it is excessively oxidized in synthesis example 1. FIG. It is an XRD pattern which shows the result of the experimental example 1 of the comparative example 1 (rest 1 day). A peak of γ-NiOOH (γred-NiOOH) is observed at 2θ = 10.5 ° to 15 °. It is an XRD pattern which shows the result of the experimental example 1 of the comparative example 2. A peak of γ-NiOOH (γred-NiOOH) is observed at 2θ = 10.5 ° to 15 °. The peak is larger than that of Comparative Example 1. It is an XRD pattern which shows the result of the experimental example 1 of Example 1 (rest 1 day). No peak is seen at 2θ = 10.5 ° to 15 °. It is an XRD pattern which shows the result of Experimental Example 1 of Example 2. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is an XRD pattern which shows the result of Experimental Example 1 of Example 3. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is an XRD pattern which shows the result of Experimental Example 1 of Example 4. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is an XRD pattern which shows the result of the experimental example 1 of the comparative example 2. The difference in the pattern due to the difference in the standing time is shown. It is a graph which shows the result of the experimental example 2 of the comparative example 1. The time change of the voltage in the process (1), (3) and (6) is shown. It is a graph which shows the result of the experimental example 2 of the comparative example 2. The time change of the voltage in the process (1), (3) and (6) is shown. It is a graph which shows the result of the experimental example 2 of Example 1. FIG. The time change of the voltage in the process (3) and (6) is shown. It is a graph which shows the result of the experimental example 2 of Example 1. FIG. The time change of the voltage in the process (3) is shown. It is a graph which shows the result of the experimental example 2 of Example 1. FIG. The time change of the voltage in the process (6) is shown. It is a graph which shows the result of the experimental example 2 of Example 2. The time change of the voltage in the process (3) and (6) is shown. It is a graph which shows the result of Experimental Example 2 of Example 3. FIG. The time change of the voltage in the process (3) and (6) is shown. It is a graph which shows the result of Experimental Example 2 of Example 3. FIG. The time change of the voltage in the process (3) is shown. It is a graph which shows the result of Experimental Example 2 of Example 3. FIG. The time change of the voltage in the process (6) is shown. It is a graph which shows the result of the experimental example 2 of Example 4. The time change of the voltage in the process (3) and (6) is shown. It is an XRD pattern which shows the result of Experimental Example 3 of Example 1. FIG. No peak is also seen at 2θ = 10.5 ° to 15 °. 6 is an XRD pattern showing the result of Experimental Example 3 of Example 6. No peak is also seen at 2θ = 10.5 ° to 15 °. It is an XRD pattern which shows the result of the experimental example 3 of the comparative example 3. A strong peak of γ-NiOOH (γred-NiOOH) is observed at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the experimental example 4 of the comparative example 3. It is a graph which shows the result of the experimental example 4 of Example 6. It is shown that the capacity and potential are larger than those of Comparative Example 3. It is a graph which shows the result of the experimental example 5 of Example 1. FIG. No drop in the potential of the discharge curve was observed after rest. It is a graph which shows the result of the experimental example 5 of Example 2. No drop in the potential of the discharge curve was observed after rest. It is a graph which shows the result of the experimental example 5 of Example 3. No drop in the potential of the discharge curve was observed after rest. It is a graph which shows the result of the cycle charge / discharge test (no pause time; 5 cycles) of Experimental Example 6 of Example 1. FIG. The curve is the 1st to 5th cycles in order from the bottom. It is a graph which shows the result of the X-ray diffraction measurement (no rest time; 5 cycles) of Experimental Example 6 of Example 1. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (no pause time; 5 cycles) of Experimental Example 6 of Example 2. FIG. The curve is the 1st to 5th cycles in order from the bottom. It is a graph which shows the result of the X-ray diffraction measurement (no rest time; 5 cycles) of Experimental Example 6 of Example 2. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (no pause time; 5 cycles) of the experimental example 6 of the comparative example 1. FIG. The curve is the 1st to 5th cycles in order from the top at the right end. It is a graph which shows the result of the X-ray diffraction measurement (no rest time; 5 cycles) of the experimental example 6 of the comparative example 1. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (no pause time; 5 cycles) of Experimental Example 6 of Example 3. FIG. The curve is the 1st to 5th cycles in order from the bottom. It is a graph which shows the result of the X-ray diffraction measurement (no rest time; 5 cycles) of Experimental Example 6 of Example 3. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (no pause time; 10 cycles) of Experimental Example 6 of Example 1. FIG. The curve is from the 1st cycle to the 10th cycle in order from the bottom. It is a graph which shows the result of the X-ray diffraction measurement (no rest time; 10 cycles) of the experimental example 6 of Example 1. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (no pause time; 10 cycles) of Experimental Example 6 of Example 2. FIG. The curve is from the 1st cycle to the 10th cycle in order from the top. It is a graph which shows the result of the X-ray diffraction measurement (no rest time; 10 cycles) of Experimental Example 6 of Example 2. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (no pause time; 10 cycles) of the experimental example 6 of the comparative example 1. FIG. The curve is the 1st to 10th cycles in order from the top at the right end. It is a graph which shows the result of the X-ray diffraction measurement (no rest time; 10 cycles) of the experimental example 6 of the comparative example 1. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (no pause time; 10 cycles) of Experimental Example 6 of Example 3. FIG. The curve is from the 1st cycle to the 10th cycle in order from the bottom. It is a graph which shows the result of the X-ray diffraction measurement (no rest time; 10 cycles) of Experimental Example 6 of Example 3. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (pause 1 hour; 5 cycles) of Experimental Example 6 of Example 1. FIG. The curve is the 1st to 5th cycles in order from the top. It is a graph which shows the result of the X-ray diffraction measurement (pause 1 hour; 5 cycles) of the experimental example 6 of Example 1. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (pause 1 hour; 5 cycles) of Experimental Example 6 of Example 2. FIG. The curve is the 1st to 5th cycles in order from the top. It is a graph which shows the result of the X-ray diffraction measurement (pause 1 hour; 5 cycles) of Experimental Example 6 of Example 2. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (pause 1 hour; 5 cycles) of the experimental example 6 of the comparative example 1. FIG. The curve is the 1st to 5th cycles in order from the top. It is a graph which shows the result of the X-ray diffraction measurement (pause 1 hour; 5 cycles) of the experimental example 6 of the comparative example 1. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (pause 1 hour; 5 cycles) of Experimental Example 6 of Example 3. FIG. The curve is the 1st to 5th cycles in order from the top. It is a graph which shows the result of the X-ray diffraction measurement (pause 1 hour; 5 cycles) of the experimental example 6 of the example 3. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (pause 1 hour; 10 cycles) of Experimental Example 6 of Example 1. FIG. The curve is the first cycle to the tenth cycle in order from the top at the right end. It is a graph which shows the result of the X-ray diffraction measurement (pause 1 hour; 10 cycles) of the experimental example 6 of Example 1. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (pause 1 hour; 10 cycles) of Experimental Example 6 of Example 2. FIG. The curve was from the 1st cycle to the 10th cycle in order from the top at the right end, and a voltage drop was observed at the 10th cycle. It is a graph which shows the result of the X-ray diffraction measurement (pause 1 hour; 10 cycles) of Experimental Example 6 of Example 2. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (pause 1 hour; 10 cycles) of Experimental Example 6 of Example 3. FIG. The curve is from the 1st cycle to the 10th cycle in order from the top. It is a graph which shows the result of the X-ray diffraction measurement (pause 1 hour; 10 cycles) of the experimental example 6 of the example 3. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (pause 2 hours; 5 cycles) of Experimental Example 6 of Example 1. FIG. The curves were from the 1st cycle to the 5th cycle in order from the top, and a voltage drop was observed at the 5th cycle. It is a graph which shows the result of the X-ray diffraction measurement (pause 2 hours; 5 cycles) of the experimental example 6 of Example 1. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (pause 2 hours; 5 cycles) of Experimental Example 6 of Example 2. FIG. The curves were from the 1st cycle to the 5th cycle in order from the top, and a voltage drop was observed at the 5th cycle. It is a graph which shows the result of the X-ray diffraction measurement (pause 2 hours; 5 cycles) of Experimental Example 6 of Example 2. FIG. No peak is seen at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (pause 2 hours; 5 cycles) of the experimental example 6 of the comparative example 1. FIG. The curves were from the 1st cycle to the 5th cycle in order from the top, and a voltage drop was observed in the 2nd cycle. It is a graph which shows the result of the X-ray diffraction measurement (pause 2 hours; 5 cycles) of the experimental example 6 of the comparative example 1. FIG. A peak of γ-NiOOH is observed at 2θ = 10.5 ° to 15 °. It is a graph which shows the result of the cycle charge / discharge test (pause 2 hours; 5 cycles) of Experimental Example 6 of Example 3. FIG. The curve is the 1st to 5th cycles in order from the top. It is a graph which shows the result of the X-ray diffraction measurement (pause 2 hours; 5 cycles) of the experimental example 6 of the example 3. FIG. No peak is seen at 2θ = 10.5 ° to 15 °.

1. 1. Primary Battery or Secondary Battery Electrode The primary battery or secondary battery electrode of the present invention is a battery electrode including an electrode current collector and an electrode active material layer containing an electrode active material, and the electrode current collector. Consists of a substance that controls the local battery reaction that occurs between the electrode collector and the electrode active material, or controls the local battery reaction that occurs between the electrode collector and the electrode active material. It has a layer composed of a substance on the surface (in particular, the substance that controls the local battery reaction is preferably a substance that controls the local battery reaction at the time of opening the circuit). Specifically, it is preferable that the electrode current collector does not contain a substance having a base potential larger than that of the electrode active material on the surface. When the electrode active material layer contains a conductive auxiliary agent, an additive, etc., the substance on the surface of the electrode current collector, the material on the surface of the conductive auxiliary agent, the additive, etc., and the electrode active material are used. It is preferable to control the local battery reaction that occurs during the period (the surface of the electrode current collector and the conductive auxiliary agent does not contain a substance having an electrode potential larger than that of the electrode active material).

<Electrode current collector>
The electrode collector is on the surface as described above, and the electrode collector is made of a substance that controls a local battery reaction that occurs between the electrode collector and the electrode active material, or the electrode. The surface has a layer made of a substance that controls a local battery reaction that occurs between the battery collector and the electrode active material. In order to control this local battery reaction, it is preferable that the electrode current collector does not contain a substance having a base potential larger than that of the electrode active material. As described above, a substance having a layer made of a substance for controlling the local battery reaction or a substance for controlling the local battery reaction on the surface (particularly, a material having a base potential larger than that of the electrode active material). Is not included in the surface of the electrode current collector), so that the electrode active material (β-NiOOH, etc.) is the positive electrode and the electrode current collector (Ni, etc.) is the negative electrode when the circuit is open, for example, when the battery is not used. It is possible to control the generation of the battery and suppress the deterioration of the battery due to the local battery reaction caused by this.

The structure of such an electrode current collector is composed of a substance having an electrode potential larger than that of the electrode active material and / or a substance electrochemically inactive with respect to the electrolyte, or more than the electrode active material. It is preferable to have a layer on the surface of a substance having a large and non-base electrode potential and / or a substance electrochemically inactive with respect to an electrolyte. When a conductive auxiliary agent, an additive, etc. is used, the conductive auxiliary material, the additive, etc. are also electrochemically inert to a substance having an electrode potential that is larger than the electrode active material and not a base potential, and / or an electrolyte. It is preferable to have a layer on the surface of a substance made of a substance having an electrode potential larger than that of the electrode active material and / or a substance electrochemically inactive with respect to an electrolyte. By adopting such a configuration, the reaction of the local battery having the electrode active material (β-NiOOH etc.) as the positive electrode and the electrode current collector (Ni etc.) as the negative electrode can be controlled more reliably at the time of opening the circuit. Therefore, it is possible to suppress the deterioration of the electrode material due to the local battery reaction and improve the durability and the capacity.

The "material having an electrode potential larger than that of the electrode active material and not being base" is not limited to a material having an electrode potential that is not significantly lower than the electrode potential of the electrode active material, and is not limited to "electrolyte". On the other hand, it shall also include "electrochemically inert substance". Such a substance is not particularly limited, but a substance having a potential higher than −0.75 V is preferable, a substance having a potential higher than −0.50 V is more preferable, and −0. Substances higher than 25V are more preferred, and substances higher than 0V are particularly preferred. Further, "a substance that is electrochemically inert to the electrolyte" can also be preferably used. On the contrary, as "a substance having an electrode potential larger than that of the electrode active material", it is preferable that the substance does not contain a substance having a potential equal to or lower than -0.75 V as compared with the electrode active material. Specifically, taking a positive electrode using nickel hydroxide as an active material such as a positive electrode for a nickel hydrogen battery or a nickel cadmium battery as an example, it is generated when a nickel hydrogen battery, a positive electrode for a nickel cadmium battery or the like is charged. Compared with β-NiOOH (+ 0.52 V vs SHE), lead, copper, gold (monovalent), platinum, silver, iridium, rhodium, etc. having a potential higher than -0.75 V are preferable, and the potential is -0.25 V. Higher copper, gold (monovalent), platinum, silver, iridium, rhodium and the like are more preferable, and gold (monovalent), platinum, silver, iridium, rhodium and the like having a potential higher than 0 V are particularly preferable. In addition, as the "substance that is electrochemically inert to the electrolyte", when the electrolyte is an aqueous solution system such as an aqueous solution of potassium hydroxide or an aqueous solution of sulfuric acid, a carbonaceous material and a conductive polymer (particularly conductive organic high). Mole) and the like can be preferably used. The carbonaceous material is not particularly limited, and carbon black such as channel black, furnace black, ketjen black, acetylene black, lamp black; graphite such as natural graphite and artificial graphite; activated carbon; amorphous carbon and the like can be preferably adopted. The conductive polymer is not particularly limited, and polythiophene, polyacetylene, polyaniline, graphite, polythiadyl and the like can be preferably adopted. These substances may be contained alone or in combination of two or more.

On the other hand, it is preferable that nickel, titanium, lithium, potassium, iron, zinc and the like having a potential lower than −0.75 V as compared with the standard electrode potential of β-NiOOH are not present on the surface of the electrode current collector. Further, when a conductive auxiliary agent, an additive or the like is used, it is preferable that the surface of the conductive auxiliary agent, the additive or the like does not have these substances.

The standard electrode potentials of each substance are lithium (Li ⁺ + e- → Li ^; -3.04 V vs SHE), potassium (K ⁺ + e- → K ^; -2.925 V vs SHE), and titanium (Ti ² ), respectively. ⁺ + 2e ^－ → Ti ； －1.63 V vs SHE), Zinc (Zn ²⁺ + 2e ^－ → Zn ； －0.763 V vs SHE), Iron (Fe ²⁺ +2e ^－ → Fe ； －0.440 V vs SHE), Nickel (Ni ²⁺ + 2e ^－ → Ni ； －0.257 V vs SHE), Lead (Pb ²⁺ + 2e ^－ → Pb ； －0.126 V vs SHE), Copper (Cu ²⁺ + e ^－ → Cu ⁺ ； + 0.337 V vs SHE), rhodium (Rh ³⁺ + 3e ^－ → Rh ； + 0.758V vs SHE), silver (Ag ⁺ + e ^－ → Ag ； + 0.799 V vs SHE), iridium (Ir ³⁺ + 3e ^－ → Ir ； + 1.156V vs SHE), platinum (Pt ²⁺ + 2e ^－ → Pt ； + 1.188 V vs SHE), gold (monovalent) (Au ⁺ + e ^－ → Au ； + 1.83 V vs SHE).

When an electrode current collector having a layer composed of a substance having an electrode potential larger than the electrode active material and / or a substance electrochemically inactive with respect to an electrolyte is adopted on the surface, the center other than the surface is used. The portion may be a substance having an electrode potential larger than that of the electrode active material and not being base, or a material having a base potential larger than that of the electrode active material. Further, the substance may be electrochemically inactive with respect to the electrolyte. That is, even a substance having a base potential larger than that of the electrode active material is electrochemically inactive to a substance having an electrode potential larger than that of the electrode active material and / or an electrolyte on the surface thereof. If a layer made of a substance is formed, it can be used as an electrode current collector. At this time, "a layer made of a substance having an electrode potential larger than that of the electrode active material and / or a substance electrochemically inert to the electrolyte is formed on the surface" means that the surface is the above-mentioned specific substance. It does not have to be completely covered with a layer consisting of the above, and includes the case where the above-mentioned specific substance is scattered on the surface. For this reason, an inexpensive material is used as the electrode active material, and a layer composed of a material having an electrode potential larger than that of the electrode active material and / or a substance electrochemically inert to the electrolyte on the surface thereof (particularly). By forming an inexpensive carbonaceous material, a conductive polymer, etc.), the electrode for the primary battery or the secondary battery of the present invention can be manufactured at a lower cost.

The thickness of the layer made of a substance having an electrode potential larger than that of the electrode active material and / or a substance electrochemically inactive with respect to the electrolyte is not particularly limited, but the electrode material is deteriorated by the local battery reaction. 5 nm to 10 mm is preferable, and 10 nm to 1 mm is more preferable, from the viewpoint of more reliably suppressing the above and further improving durability and capacity.

The method for forming a layer consisting of a substance having an electrode potential larger than that of the electrode active material and / or a substance electrochemically inert to the electrolyte on the surface of the electrode current collector is not particularly limited. For example, a coating method, a plating method, a vapor deposition method, or the like can be adopted. When the coating method is adopted, for example, roller coating such as an applicator roll; screen coating; doctor blade method; spin coating; bar coater or the like can be used for coating. When the plating method is adopted, either electrolytic plating or electroless plating may be used.

<Electrode active material layer>
The electrode active material in the electrode active material layer is not particularly limited, and materials conventionally used for the positive electrode or the negative electrode of the primary battery or the secondary battery can be used.

Specifically, for nickel hydrogen batteries, nickel cadmium batteries, rechargeable alkaline batteries, etc., the electrodes for the primary battery or secondary battery of the present invention should be used as the positive electrode from the viewpoint of further suppressing deterioration due to the local battery reaction. In this case, it is preferable to use nickel hydroxide, which is usually used as a positive electrode active material, β-NiOOH formed in the charging process, manganese dioxide, or the like.

For the lithium ion secondary battery and the like, the electrode for the primary battery or the secondary battery of the present invention may be used for either the positive electrode or the negative electrode. When used as a positive electrode, LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiFePO _4, LiNi _{x Mny} Coz O ₂ (0 <x, 0 <y, 0 < _z , x + y + z) used as a positive electrode active material. Lithium-containing transition metal oxides such as (= 1) can be adopted, and when used as a negative electrode, lithium metal used as a negative electrode active material, natural graphite, graphite such as artificial graphite, activated carbon, etc. Lithium-containing transition metal oxides such as carbonaceous materials and Li _v Ti _w O ₄ (0 <v, 0 <w, v + w = 3) can be employed.

For lead storage batteries and the like, it is preferable to use the electrodes for the primary battery or the secondary battery of the present invention as the positive electrode from the viewpoint of further suppressing deterioration due to the local battery reaction, and in this case, lead oxide usually used as the positive electrode active material. Etc. can be adopted.

In the above, only the example of the secondary battery is described, but the electrode of the present invention can be adopted in various primary batteries.

Among these, in nickel-metal hydride batteries, nickel-cadmium batteries, etc., which have a remarkable memory effect, nickel hydroxide, β-NiOOH, etc. are preferable because deterioration of the batteries can be suppressed and durability and capacity can be further improved. ..

The content of these electrode active materials in the electrode active material layer is not particularly limited, and has been conventionally applied to the positive electrode or the negative electrode of a primary battery or a secondary battery that employs the electrode for the primary battery or the secondary battery of the present invention. Can be to the extent that it is done.

<Conductive aid>
In the present invention, the electrode active material layer may also contain a conductive auxiliary agent.

As the conductive auxiliary agent, it is preferable to use a material which is an electronically conductive material and can control the local battery reaction. Specifically, a conductive material such as natural graphite, artificial graphite or other graphite; carbon black; acetylene black; Ketjen black; carbon whisker; carbon fiber; vapor-grown carbon or the like is contained as one kind or a mixture thereof. Can be done.

In addition to the above components, the electrode active material layer may also contain a binder, a thickener, or the like.

The binder is usually a thermoplastic resin such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride, polyethylene, polypropylene; ethylene-propylene-dienter polymer (EPDM), sulfonated EPDM, styrene butadiene rubber (SBR). , Fluorine rubber and other polymers having rubber elasticity can be used as one kind or a mixture of two or more kinds. The amount of the binder added is preferably about 2 to 15% by mass with respect to the total mass of the negative electrode active material layer.

As the thickener, usually, polysaccharides such as carboxymethyl cellulose and methyl cellulose can be used as one kind or a mixture of two or more kinds.

These mixing methods are physical mixing, and uniform mixing is preferable. Therefore, it is possible to use a powder mixer such as a V-type mixer, an S-type mixer, a mixer, a ball mill, a planetary ball mill, etc., either dry or wet.

In the present invention, the method for forming the electrode active material layer on the electrode current collector is not particularly limited. For example, various components such as an electrode active material are mixed with water to prepare a paste composition for forming an electrode (positive electrode or negative electrode) active material layer, and then the paste composition is impregnated or impregnated into the above-mentioned electrode current collector. Examples thereof include a method of applying and drying.

As for the coating method, for example, roller coating such as an applicator roll; screen coating; doctor blade method; spin coating; bar coater or the like can be used for coating. Further, the drying conditions are not particularly limited, and can be adopted within the range usually used for primary batteries or secondary batteries.

2. 2. Primary Battery or Secondary Battery The primary battery or secondary battery of the present invention comprises an electrode for the primary battery or secondary battery of the present invention. Hereinafter, the configuration will be described for each battery.

<Alkaline secondary battery>
When the electrode of the present invention is used in an alkaline secondary battery such as a nickel hydrogen battery, a nickel cadmium battery, or a rechargeable alkaline battery, nickel hydroxide (β-NiOOH during charging), manganese dioxide, or the like is used as the electrode active material. It is preferable to use the electrode of the present invention as a positive electrode.

Examples of other members include a negative electrode, an electrolytic solution, a separator and the like. These may be appropriately manufactured or commercially available, and members and materials in known alkaline secondary batteries such as nickel-metal hydride batteries and nickel-cadmium batteries can be used. Among these, as the material of the negative electrode, a hydrogen storage alloy is preferable in the case of a nickel hydrogen battery, and cadmium hydroxide or the like is preferable in the case of a nickel cadmium battery. Further, as the material of the electrolytic solution, an aqueous solution of potassium hydroxide or the like is preferable.

The hydrogen storage alloy is not particularly limited, and an alloy conventionally used as a negative electrode active material for a nickel hydrogen battery can be used. For example, an alloy capable of storing hydrogen and generally called an AB ₂ system, an AB ₅ system, or an AB ₂ and AB ₅ mixed system may be used, and the composition thereof is not particularly limited. Of these, alloys in which part of Ni in the AB ₅ type alloy MHNi ₅ (MH is a mixture of rare earth elements (mischmetal)) are replaced with Co, Mn, Al, Cu, etc. have excellent charge / discharge cycle life. It is preferable because it has characteristics and high discharge capacity.

In the case of a nickel hydrogen battery or a nickel cadmium battery, this alkaline secondary battery can control the local battery reaction to suppress the production of γ-NiOOH (γred-NiOOH), so that it can be rotated by X-ray diffraction with CuKα rays. It is suppressed that a new diffraction peak is exhibited at the position of 10.5 to 15 degrees of the folding angle 2θ.

<Lithium-ion secondary battery>
The electrode of the present invention can be used for both the positive electrode and the negative electrode in the lithium ion secondary battery, and it is preferable to use the electrode for both.

Examples of other members include an electrolytic solution and a separator. These may be appropriately manufactured or commercially available, and known members and materials for lithium batteries can be used.

<Lead-acid battery>
When the electrode of the present invention is used in a lead storage battery, it is preferable to use lead dioxide as the electrode active material and to use the electrode of the present invention as a positive electrode.

Examples of other members include a negative electrode, an electrolytic solution, a separator and the like. These may be appropriately manufactured or commercially available, and known members and materials in lead-acid batteries can be used.

In addition, the electrode of the present invention can also be preferably adopted as an electrode (positive electrode or negative electrode) of a well-known primary battery. As the other constituent members at this time, well-known members may be adopted.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

[Synthesis Example 1: Synthesis of β-NiOOH]
Synthesis was carried out using commercially available Ni (OH) ₂ and NaClO according to the following reaction formula.
Reaction formula: 2Ni (OH) ₂ + NaClO → 2NiOOH + NaCl + H ₂ O.

Add 10 ml of distilled water to 0.4 g of Ni (OH) ₂ to make a slurry, add 10 ml of NaClO and 10 ml of 8M sodium hydroxide aqueous solution to adjust the pH to 13 or higher, and use a hot stirrer to adjust the temperature. The reaction was carried out while keeping the temperature at 20 ° C. and stirring for 1 hour and 30 minutes. This was suction filtered and then dried in the air at 40 ° C. for 1 day.

When X-ray diffraction measurement with CuKα ray was performed, the diffraction pattern as shown in FIG. 1 was obtained, and characteristic peaks were observed at 2θ = about 19 ° and about 38 °. In addition, since no peak was observed at 2θ = 10.5 ° to 15 ° and no large peak was observed at an angle higher than 2θ = 40 °, it was judged that β-NiOOH was obtained instead of γ-NiOOH. .. This pattern is consistent with the pattern in Fig. 3 of J. Pan et al. / Electrochemica Acta 54 (2009) 3812-3818.

When the reaction time was lengthened under the same conditions, a peak appeared in the XRD pattern between 2θ = 10.5 ° and 15 °, as shown in FIG. This pattern was similar to the peak of γ-NiOOH in Fig. 3 of J. Pan et al. / Electrochemica Acta 54 (2009) 3812-3818, and it was found that γ-NiOOH (γox-NiOOH) was generated. ..

From the above results, it was found that β-NiOOH is produced by oxidizing Ni (OH) ₂ , and γ-NiOOH (γox-NiOOH) is produced by excessive oxidation.

[Comparative Example 1: Nickel mesh]
To β-NiOOH prepared in Synthesis Example 1, acetylene black as a conductive auxiliary agent and PTFE as a binder were added at a ratio of β-NiOOH: acetylene black: binder at a ratio of 80:15: 5 (mass%). It was mixed well to prepare a paste composition for forming a positive electrode active material layer.

A nickel mesh (manufactured by Nirako Co., Ltd .; nickel wire mesh 100mesh) is used as the positive electrode support (electrode current collector), and the positive electrode is used so that the thickness of the positive electrode support is 0.1 to 10 mm (particularly 1 mm). The paste composition for forming an active material layer was applied and dried to obtain a positive electrode for a secondary battery of Comparative Example 1.

[Comparative Example 2: Titanium Mesh]
Similar to Comparative Example 1 except that a titanium mesh (manufactured by Nirako Co., Ltd .; titanium wire mesh 100 mesh) was used as the positive electrode support (electrode current collector) instead of the nickel mesh, for the secondary battery of Comparative Example 2. A positive electrode was obtained.

[Example 1: Gold mesh]
For the secondary battery of Example 1, as in Comparative Example 1, except that a gold mesh (manufactured by Nirako Co., Ltd .; wire mesh 100 mesh) was used as the positive electrode support (electrode current collector) instead of the nickel mesh. A positive electrode was obtained.

[Example 2: Platinum mesh]
Similar to Comparative Example 1, for the secondary battery of Example 2, except that a platinum mesh (manufactured by Nirako Co., Ltd .; platinum wire mesh 100 mesh) was used as the positive electrode support (electrode current collector) instead of the nickel mesh. A positive electrode was obtained.

[Example 3: Carbon coated nickel mesh]
Using the E-1010 type Hitachi ion sputter, starting with an additional current of 20 A according to the manual, the vapor deposition was continued for about 10 seconds until this became 0 A, and a carbon-coated nickel mesh was obtained. The film thickness at this time is 12 nm according to the manual.

A positive electrode for a secondary battery of Example 3 was obtained in the same manner as in Comparative Example 1 except that a carbon-coated nickel mesh was used as the positive electrode support (electrode current collector) instead of the nickel mesh.

[Example 4: Carbon coated titanium mesh]
Using the E-1010 type Hitachi ion spatter, the carbon-coated titanium mesh was obtained by starting with an additional current of 20 A according to the manual and continuing the vapor deposition for about 10 seconds until this became 0 A. The film thickness at this time is 12 nm according to the manual.

A positive electrode for a secondary battery of Example 4 was obtained in the same manner as in Comparative Example 1 except that a carbon-coated titanium mesh was used instead of a nickel mesh as the positive electrode support (electrode current collector).

[Experimental Example 1: Generation of γ-NiOOH (γred-NiOOH) at rest]
A glass cell (2) using the positive electrode for the secondary battery of Examples 1 to 4 and Comparative Examples 1 and 2 as the working electrode, Pt as the counter electrode, and the Ag / AgCl reference electrode as the reference electrode, and 8M KOH as the electrolytic solution. Next battery) was manufactured.

After discharging to the middle of the plateau (region where the potential change is small) of +0.5 to +0.35 V (vs SHE), it was allowed to stand in an open circuit state. For Examples 1 to 4 and Comparative Examples 1 and 2, the XRD patterns of the positive electrode materials after various lapses of time are shown below.
Fig. 3 Comparative Example 1 (nickel mesh) 1 day later Fig. 4 Comparative Example 2 (titanium mesh) 2 days later Fig. 5 Example 1 (gold mesh) 1 day later Fig. 6 Example 2 (platinum mesh) 3 days later Fig. 7 Example 3 ( Carbon-coated nickel mesh) 1 day later FIG. 8 Example 4 (carbon-coated titanium mesh) 1 day later.

Focusing on the pattern in which 2θ is 10.5 ° to 15 °, peaks appeared in Comparative Examples 1 and 2 using nickel mesh and titanium mesh as the electrode support (electrode current collector) (FIGS. 3 to 4). .. Titanium, which has a lower standard electrode potential than nickel, had a larger peak.

Further, the same experiment was performed on the titanium mesh of Comparative Example 2, and the XRD pattern at a standing time of 30 minutes and 1 hour is shown in FIG. The intensity of this peak increased as the standing time increased.

Y. Sato et al. / Journal of Power Sources 93 (2001) 20-24 states that this is the peak of γ-NiOOH. It is also stated that the generation of γ-NiOOH is the cause of the memory effect. The γ-NiOOH generated by the local battery reaction has a diffraction peak at a position of 10.5 to 15 degrees of the diffraction angle 2θ by X-ray diffraction with CuKα rays. On the other hand, γ-NiOOH generated by overcharging also has a diffraction peak at a position of 10.5 to 15 degrees of the diffraction angle 2θ, and although the peak positions are similar, it is not clear whether they are the same substance. This is because the charging process is an oxidation process for the electrode active material (β-NiOOH), whereas the process in which a local battery reaction occurs with the electrode current collector (Ni) is the electrode active material (β). -NiOOH) is a reduction process. Γ-NiOOH in this document can be expressed as γ-NiOOH (γred-NiOOH). Γ-NiOOH, which appears due to overcharging and is more oxidized than β-NiOOH, can be expressed as γ-NiOOH (γox-NiOOH). However, at this time, there is no report stating that γox-NiOOH and γred-NiOOH are materially different.

On the other hand, in Examples 1 and 2 in which the gold mesh and the platinum mesh were used as the electrode support (electrode current collector), this peak did not appear (FIGS. 5 to 6). The potential of β-NiOOH is +0.52 V based on the standard hydrogen electrode (SHE) when fully charged (Source: Overview of Panasonic Rechargeable Nickel Metal Hydride Battery). Nickel and titanium have large and low potentials with respect to β-NiOOH. In contrast, gold and platinum have large, non-base potentials.

When the battery cell is opened, a local battery reaction occurs between the electrode material (electrode active material) in the electrode and the electrode support (electrode current collector) based on the potential difference. In this local battery, when the electrode support is a nickel mesh or a titanium mesh (Comparative Examples 1 and 2), β-NiOOH becomes a positive electrode, and when the electrode support (electrode current collector) is a gold mesh or a platinum mesh. In (Examples 1 and 2), β-NiOOH serves as a negative electrode. When the electrode support (electrode current collector) was made of nickel mesh or titanium mesh (Comparative Examples 1 and 2), γ-NiOOH (γred-NiOOH) was generated, so β-NiOOH was generated by the local battery reaction. It was found that "γ-NiOOH (γred-NiOOH)" was produced when acting as a positive electrode.

On the other hand, even if the electrode support (electrode current collector) is a nickel mesh or titanium mesh generated by γ-NiOOH (γred-NiOOH), when carbon coating is applied (Examples 3 to 4), " The peak of "γ-NiOOH (γred-NiOOH)" did not appear. Since carbon is inert in this electrolyte, local battery reaction does not occur, β-NiOOH does not act as a positive electrode, and when the electrode support (electrode current collector) is a gold mesh or platinum mesh. Similar to (Examples 1 and 2), it can be said that "γ-NiOOH (γred-NiOOH)" was not generated. Based on the above, in secondary batteries that use nickel hydroxide as the electrode active material, such as nickel-metal hydride batteries and nickel-cadmium secondary batteries, the electrode that controls the local battery reaction in which β-NiOOH acts as the positive electrode is "γ. It can be seen that the formation of "-NiOOH (γred-NiOOH)" can be prevented. It was also shown that the electrode reaction of nickel and titanium can be shielded by coating with carbon. It is considered that the electrode reaction can be shielded even when coated with a conductive polymer or the like other than carbon.

[Experimental example 2: Difference in memory effect and capacity (1)]
Similar to Experimental Example 1, a glass cell (secondary battery) was produced in the same manner as in Experimental Example 1 by using the positive electrodes for secondary batteries of Examples 1 to 4 and Comparative Examples 1 and 2 as working electrodes, respectively.

The following process:
(1) Discharge until the end of the plateau of +0.5 to +0.35 V (vs SHE) (2) Charge for 6 hours (3) Discharge to the middle of the plateau of +0.5 to +0.35 V (vs SHE) (4) Pause (comparative example) 1 (nickel mesh): 1 week, Examples 1 to 4 and Comparative Example 2 (Other): 5 hours)
(5) Charging for 6 hours (6) + 0.5 to + 0.35 V (vs SHE) Charging and discharging according to the discharge until the end of the plateau was performed in this order with a current density of 30 mA / g.

In the process of (2) and (5), both are completely charged.

For Examples 1 to 4 and Comparative Examples 1 and 2, the time changes of the voltage in various processes are as follows:
FIG. 10 Comparative Example 1 (Nickel Mesh) Processes (1), (3), (6)
FIG. 11 Comparative Example 2 (titanium mesh) Processes (1), (3), (6)
FIG. 12 Example 1 (gold mesh) Process (3), (6)
FIG. 13 Example 2 (platinum mesh) Processes (3), (6)
FIG. 14 Example 3 (carbon coated nickel mesh) Processes (3) and (6)
FIG. 15 Example 4 (carbon coated titanium mesh) Processes (3) and (6)
Shown in.

When the electrode support was made of nickel mesh or titanium mesh (Comparative Examples 1 and 2), a phenomenon was observed in which the voltage in the process of (6) decreased sharply as compared with the process of (1). This represents the memory effect. On the other hand, when a gold mesh, a platinum mesh, a carbon-coated nickel mesh, or a carbon-coated titanium mesh is used (Examples 1 to 4), the voltage in the process of (6) is (3). Compared to the process, it did not decrease sharply.

From the above results, the memory effect was observed when the electrode support that causes a local battery reaction in which β-NiOOH acts as a positive electrode is used in Experimental Example 1. Based on the above, in secondary batteries that use nickel hydroxide as the electrode active material, such as nickel-metal hydride batteries and nickel-cadmium secondary batteries, the electrodes that control the local battery reaction in which β-NiOOH acts as the positive electrode have a memory effect. It can be seen that the durability can be improved without causing the problem.

Comparing the elapsed time, when a gold mesh, a platinum mesh, a carbon-coated nickel mesh, or a carbon-coated titanium mesh is used as the electrode support (Examples 1 to 4), the electromotive force is significantly reduced from 10,000 to 10,000. It takes about 25,000 seconds. On the other hand, when a nickel mesh or a titanium mesh is used, it takes about 3000 to 13000 seconds. In particular, when Comparative Example 2 and Example 4 in which the same titanium is used as the electrode current collector are compared, the time for which the electromotive force is significantly reduced jumps from about 3000 seconds to about 10000 seconds by applying the carbon coat. Is improving. In other words, it can be seen that the capacity of the battery has also improved dramatically. From this, when nickel mesh or titanium mesh is used (Comparative Examples 1 and 2), the local battery reaction that occurs in parallel acts to reduce the capacity of the battery even when the normal battery is used. The electrode for a secondary battery of the present invention can suppress this action.

[Example 5: Gold mesh (conductive aid nickel; starting material Ni (OH) ₂ )]
Commercially available Ni (OH) ₂ with commercially available Ni metal powder (Ni powder) as a conductive auxiliary agent, PTFE as a binder, Ni (OH) ₂ : acetylene black: binder 80: 15: 5 (mass) %) Each was added and mixed well to prepare a paste composition for forming a positive electrode active material layer.

A gold mesh (manufactured by Nirako Co., Ltd .; wire mesh 100mesh) is used as the positive electrode support (electrode current collector), and the positive electrode is used so that the thickness of the positive electrode support is 0.1 to 10 mm (particularly 1 mm). The paste composition for forming an active material layer was applied and dried to obtain a positive electrode for a secondary battery of Example 5.

[Example 6: Gold mesh (conductive aid acetylene black; starting material Ni (OH) ₂ )]
A positive electrode for a secondary battery of Example 6 was obtained in the same manner as in Example 5 except that acetylene black was used as the conductive auxiliary agent instead of Ni metal powder.

[Comparative Example 3: Nickel mesh (conductive aid acetylene black; starting material Ni (OH) ₂ )]
Nickel mesh (manufactured by Niraco Co., Ltd .; nickel wire mesh 100mesh) was used as the positive electrode support (electrode current collector) instead of gold mesh, and acetylene black was used as the conductive auxiliary agent instead of Ni metal powder. A positive electrode for a secondary battery of Comparative Example 3 was obtained in the same manner as in Example 5 except for the above.

[Experimental example 3: X-ray diffraction measurement result when resting in the middle of discharge]
<In the case of starting material β-NiOOH>
Similar to Experimental Example 1, a glass cell (secondary battery) was produced in the same manner as in Experimental Example 1 by using the positive electrodes for the secondary battery of Example 1 (gold mesh) as working electrodes.

The following process:
(1) Discharge until the end of the plateau of +0.5 to +0.35 V (vs SHE) (2) Charge for 6 hours (3) Discharge to the middle of the plateau of +0.5 to +0.35 V (vs SHE) (4) Pause for 3 days Therefore, charging and discharging were performed in this order with a current density of 30 mA / g.

The results are shown in FIG. As a result, no peak of γ-NiOOH was observed.

<In the case of starting material Ni (OH) ₂ >
Similar to Experimental Example 1, a glass cell (secondary battery) was produced in the same manner as in Experimental Example 1 by using the positive electrodes for secondary batteries of Example 6 and Comparative Example 3 (gold mesh and nickel mesh) as working electrodes, respectively. ..

The following process:
(1) 6-hour charge (2) Discharge until the end of the plateau of +0.5 to +0.35 V (vs SHE) * (1) and (2) were repeated 3 times.
(3) Charging for 6 hours (4) Discharging halfway through the plateau of +0.5 to +0.35 V (vs SHE) (5) Charging and discharging according to the pause 1 week were all performed in this order with a current density of 30 mA / g. ..

For Example 6 and Comparative Example 3, the XRD patterns of the positive electrode material after various lapses of time are as follows:
FIG. 17 Example 6 (gold mesh; starting material Ni (OH) ₂ )
FIG. 18 Comparative Example 3 (nickel mesh; starting material Ni (OH) ₂ )
Shown in.

As a result, the peak of γ-NiOOH was observed in Comparative Example 3, but the peak of γ-NiOOH was not observed in Example 6.

[Experimental example 4: Difference in capacity]
Similar to Experimental Example 1, a glass cell (secondary battery) was produced in the same manner as in Experimental Example 1 by using the positive electrodes for secondary batteries of Example 6 and Comparative Example 3 as working electrodes, respectively.

The following process:
(1) 6-hour charge (2) Discharge until the end of the plateau of +0.5 to +0.35 V (vs SHE) * (1) and (2) were repeated 3 times.
According to this, charging and discharging were performed in this order with a current density of 30 mA / g.

The discharge curves in each final discharge process are shown in FIG. 19 Comparative Example 3 (nickel mesh; starting material Ni (OH) ₂ ).
FIG. 20 Example 6 (gold mesh; starting material Ni (OH) ₂ )
Shown in.

As a result, even when the starting material is Ni (OH) ₂ , the capacity is larger and the potential is higher when the gold mesh is used than when the nickel mesh is used as the electrode current collector. I understand.

[Experimental example 5: Difference in memory effect]
Similar to Experimental Example 1, a glass cell (secondary battery) was produced in the same manner as in Experimental Example 1 by using the positive electrodes for secondary batteries of Examples 1 to 3 as working electrodes.

The following process:
(1) Discharge until the end of the plateau of +0.5 to +0.35 V (vs SHE) (2) Charge for 6 hours (3) Discharge to the middle of the plateau of +0.5 to +0.35 V (vs SHE) (4) Pause for 1 week (4) 5) Charging for 6 hours (6) + 0.5 to + 0.35 V (vs SHE) was charged and discharged according to the discharge until the end of the plateau, all in this order with a current density of 30 mA / g.

In the process of (2) and (5), both are completely charged.

For Examples 1 to 3, the time changes of the voltage in various processes are as follows:
FIG. 21 Example 1 (gold mesh)
FIG. 22 Example 2 (platinum mesh)
FIG. 23 Example 3 (carbon coated nickel mesh)
Shown in.

In each case, no drop in the potential of the discharge curve was observed after rest.

[Experimental example 6: Cycle charge / discharge test with rest]
<No pause (0 hours)>
Similar to Experimental Example 1, a glass cell (secondary battery) was produced in the same manner as in Experimental Example 1 by using the positive electrodes for secondary batteries of Examples 1 to 3 and Comparative Example 1 as working electrodes, respectively.

The following process:
Process I (normal charge / discharge):
(1) Discharge until the end of the plateau of +0.5 to +0.35 V (vs SHE) (2) Charge for 6 hours * (1) and (2) were repeated 3 times.
Process II (discharged to SOC 40%):
(3) 2-hour discharge process III (charge / discharge with SOC 40-60%):
(4) 50-minute charge (5) 40-minute discharge * (4) and (5) were repeated 5 or 10 times (5 cycles or 10 cycles).
According to this, charging and discharging were performed in this order with a current density of 30 mA / g.

By making the charging time longer than the discharging time, the discharged portion could be charged.

Further, after that, X-ray diffraction measurement of each sample was performed.

Note that SOC is an abbreviation for State of Charge and represents the remaining capacity of the battery. For example, SOC 40% indicates that the remaining capacity is 40% of the total capacity.

The results of the cycle charge / discharge test and the X-ray diffraction measurement for Examples 1 to 3 and Comparative Example 1 are as follows:
FIG. 24 Example 1 (gold mesh; 5 cycles) cycle charge / discharge test FIG. 25 Example 1 (gold mesh; 5 cycles) X-ray diffraction measurement FIG. 26 Example 2 (platinum mesh; 5 cycles) cycle charge / discharge test FIG. 27 Example 2 (Platinum mesh; 5 cycles) X-ray diffraction measurement FIG. 28 Comparative Example 1 (Nickel mesh; 5 cycles) Cycle charge / discharge test FIG. 29 Comparative Example 1 (Nickel mesh; 5 cycles) X-ray diffraction measurement FIG. 30 Example 3 (Carbon-coated nickel mesh; 5 cycles) Cycle charge / discharge test Fig. 31 Example 3 (Carbon-coated nickel mesh; 5 cycles) X-ray diffraction measurement Fig. 32 Example 1 (Gold mesh; 10 cycles) Cycle charge / discharge test Fig. 33 Example 1 (gold mesh; 10 cycles) X-ray diffraction measurement Fig. 34 Example 2 (platinum mesh; 10 cycles) cycle charge / discharge test Fig. 35 Example 2 (platinum mesh; 10 cycles) X-ray diffraction measurement Fig. 36 Comparative example 1 (Nickel mesh; 10 cycles) Cycle charge / discharge test Fig. 37 Comparative Example 1 (Nickel mesh; 10 cycles) X-ray diffraction measurement Fig. 38 Example 3 (Carbon-coated nickel mesh; 10 cycles) Cycle charge / discharge test Fig. 39 Example 3 (Carbon-coated nickel mesh; 10 cycles) Shown in X-ray diffraction measurement.

<1 hour rest time>
Similar to Experimental Example 1, a glass cell (secondary battery) was produced in the same manner as in Experimental Example 1 by using the positive electrodes for secondary batteries of Examples 1 to 3 and Comparative Example 1 as working electrodes, respectively.

The following process:
Process I (normal charge / discharge):
(1) Discharge until the end of the plateau of +0.5 to +0.35 V (vs SHE) (2) Charge for 6 hours * (1) and (2) were repeated 3 times.
Process II (discharged to SOC 40%):
(3) 2-hour discharge process III (charge / discharge with SOC 40-60%):
(4) 1-hour rest (5) 50-minute charge (6) 1-hour rest (7) 40-minute discharge * (4) to (7) were repeated 5 or 10 times (5 cycles or 10 cycles).
According to this, charging and discharging were performed in this order with a current density of 30 mA / g.

Further, after that, X-ray diffraction measurement of each sample was performed.

The results of the cycle charge / discharge test and the X-ray diffraction measurement for Examples 1 to 3 and Comparative Example 1 are as follows:
FIG. 40 Example 1 (gold mesh; 5 cycles) cycle charge / discharge test FIG. 41 Example 1 (gold mesh; 5 cycles) X-ray diffraction measurement FIG. 42 Example 2 (platinum mesh; 5 cycles) cycle charge / discharge test FIG. 43 Example 2 (Platinum mesh; 5 cycles) X-ray diffraction measurement Fig. 44 Comparative Example 1 (Nickel mesh; 5 cycles) Cycle charge / discharge test Fig. 45 Comparative Example 1 (Nickel mesh; 5 cycles) X-ray diffraction measurement Fig. 46 Example 3 (Carbon-coated nickel mesh; 5 cycles) Cycle charge / discharge test Fig. 47 Example 3 (Carbon-coated nickel mesh; 5 cycles) X-ray diffraction measurement Fig. 48 Example 1 (Gold mesh; 10 cycles) Cycle charge / discharge test Fig. 49 Example 1 (gold mesh; 10 cycles) X-ray diffraction measurement Fig. 50 Example 2 (platinum mesh; 10 cycles) Cycle charge / discharge test Fig. 51 Example 2 (platinum mesh; 10 cycles) X-ray diffraction measurement Fig. 52 Example 3 (Carbon-coated nickel mesh; 10 cycles) Cycle charge / discharge test FIG. 53 Example 3 (Carbon-coated nickel mesh; 10 cycles) Shown in X-ray diffraction measurement.

<2 hours of rest time>
Similar to Experimental Example 1, a glass cell (secondary battery) was produced in the same manner as in Experimental Example 1 by using the positive electrodes for secondary batteries of Examples 1 to 3 and Comparative Example 1 as working electrodes, respectively.

The following process:
Process I (normal charge / discharge):
(1) Discharge until the end of the plateau of +0.5 to +0.35 V (vs SHE) (2) Charge for 6 hours * (1) and (2) were repeated 3 times.
Process II (discharged to SOC 40%):
(3) 2-hour discharge process III (charge / discharge with SOC 40-60%):
(4) 2-hour rest (5) 50-minute charge (6) 2-hour rest (7) 40-minute discharge * (4) to (7) were repeated 5 or 10 times (5 cycles or 10 cycles).
According to this, charging and discharging were performed in this order with a current density of 30 mA / g.

Further, after that, X-ray diffraction measurement of each sample was performed.

The results of the cycle charge / discharge test and the X-ray diffraction measurement for Examples 1 to 3 and Comparative Example 1 are as follows:
FIG. 54 Example 1 (gold mesh; 5 cycles) cycle charge / discharge test Fig. 55 Example 1 (gold mesh; 5 cycles) X-ray diffraction measurement Fig. 56 Example 2 (platinum mesh; 5 cycles) Cycle charge / discharge test Fig. 57 Example 2 (Platinum mesh; 5 cycles) X-ray diffraction measurement Fig. 58 Comparative Example 1 (Nickel mesh; 5 cycles) Cycle charge / discharge test Fig. 59 Comparative Example 1 (Nickel mesh; 5 cycles) X-ray diffraction measurement Fig. 60 Example 3 (Carbon-coated nickel mesh; 5 cycles) Cycle charge / discharge test FIG. 61 Example 3 (Carbon-coated nickel mesh; 5 cycles) Shown in X-ray diffraction measurement.

From the above results, when the gold mesh, platinum mesh and carbon-coated nickel mesh were used, no γ-NiOOH was observed even when the rest was sandwiched for 2 hours. On the other hand, when the nickel mesh was used, the formation of γ-NiOOH was observed by sandwiching the rest for 2 hours. In general, it is considered that a considerable amount (usually 5% or more) of production is required for the peak to be seen by X-ray diffraction, and a considerable amount of γ-NiOOH is produced by resting for 2 hours. With the formation of this γ-NiOOH, the cycle characteristics deteriorated when the nickel mesh was used by sandwiching the rest for 2 hours, but the cycle characteristics were deteriorated when the gold mesh, platinum mesh and carbon coated nickel mesh were used. I was able to maintain it. In particular, when a gold mesh and a carbon-coated nickel mesh were used, the cycle characteristics could be further maintained.

The above results are not applicable only to nickel-metal hydride batteries using β-NiOOH or Ni (OH) ₂ as the positive electrode active material, but also primary batteries or secondary batteries using the positive electrode active materials of various batteries. It also applies to.

For example, even when a primary battery is manufactured using MnO ₂ as the positive electrode active material, nickel mesh is used as the positive electrode current collector, although not as much as when β-NiOOH or Ni (OH) ₂ is used as the positive electrode active material. By using a nickel mesh instead of nickel, the capacity and potential could be improved. Further, as in the above experimental example, by sandwiching the rest, it was possible to read the change in the crystal structure due to the difference between the nickel mesh, the gold mesh and the platinum mesh.

Claims (18)

A battery electrode including an electrode current collector and an electrode active material layer containing an electrode active material.
The electrode current collector is composed of a material that controls a local battery reaction that occurs between the electrode collector and the electrode active material, or occurs between the electrode collector and the electrode active material. An electrode for a primary battery or a secondary battery having a layer made of a substance that controls a local battery reaction on the surface. The electrode according to claim 1, which is an electrode for a secondary battery. The electrode according to claim 1 or 2, wherein the substance that controls the local battery reaction is a substance that controls the local battery reaction at the time of opening the circuit. The electrode according to any one of claims 1 to 3, wherein the local battery reaction is the same reaction as the electrode reaction when the battery is used. The electrode according to any one of claims 1 to 4, wherein the electrode current collector does not contain a substance having a base potential larger than that of the electrode active material on the surface. The electrode according to claim 5, wherein the substance having a large and low electrode potential is a substance having a potential equal to or lower than −0.75 V as compared with the electrode active material. The electrode according to any one of claims 1 to 6, wherein the substance that controls the local battery reaction is a substance having an electrode potential that is larger than that of the electrode active material and is not base. The electrode according to claim 7, wherein the substance having a large and non-basic electrode potential is a substance having a potential higher than −0.75 V as compared with the electrode active material. The electrode according to any one of claims 1 to 8, wherein the substance that controls the local battery reaction is a substance that is electrochemically inactive with respect to the electrolyte. Claim 1 to claim 1, wherein the electrode active material contains at least one selected from the group consisting of nickel hydroxide, β-NiOOH, lithium-containing transition metal oxide, lithium metal, carbonaceous material, lead oxide, and manganese dioxide. 9. The electrode according to any one of 9. The electrode according to any one of claims 1 to 10, wherein the electrode active material contains nickel hydroxide and / or β-NiOOH. 7. Electrodes. The electrode according to any one of claims 9 to 11, wherein the substance electrochemically inert to the electrolyte contains at least one selected from the group consisting of a carbonaceous material and a conductive polymer. A primary battery or a secondary battery comprising the electrode according to any one of claims 1 to 13. The battery according to claim 14, which is a secondary battery. The battery according to claim 14 or 15, which is a nickel hydrogen battery, a nickel cadmium battery, a rechargeable alkaline battery, a lithium ion secondary battery or a lead storage battery. The battery according to any one of claims 14 to 16, which is a nickel hydrogen battery or a nickel cadmium battery. The battery according to claim 17, wherein the electrode active material is suppressed from exhibiting a new diffraction peak at a position of 10.5 to 15 degrees of a diffraction angle 2θ by X-ray diffraction with CuKα rays.

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