JPS5887758A - Positive electrode for battery and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a solid state battery having high ionic conductivity, easily workable positive electrode, and no electrolyte leakage by making contain ion conductive solid containing an electrolyte comprising either metallic ion of groupsIand II of the periodic table, an organic high polymer compound, and an organic solbent. CONSTITUTION:A solid electrolyte or an ion conductive solid is used as a separator, a metal of groupsIor II of the periodic table is used as a negative electrode. This constitution makes a battery solid or solid state, and provides the battery having no electrolyte leakage and high reliability same as a solid state battery. Ion conductive solid used for this battery is superior to a solid electrolyte in terms of ionic conductivity, mechanical workability, and cost. E, F, G of the figure show each of discharge performance of a battery having of 60, 52, 45 volume percent of an organic solvent respectively. As the ratio of an organic solvent in an ion conductive solid is increased, the discharge performance of a battery is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a positive electrode body for a battery containing a composition with high ionic conductivity and a method for producing the same. The present invention relates to a positive electrode body for a battery, which includes a solid body composition which is imparted with properties and has extremely high ionic conductivity, and a method for producing the same.

In recent years, with the increase in demand for electronic devices for mobile phone use, there has been a demand for high performance, compact, and lightweight devices. Along with this, batteries that serve as power sources for devices are required to have high energy density, small size, and thinness, and also need to be highly reliable as components.

Generally, the positive electrode body of a battery consists of a tangential active material and a conductive agent.

Consists of a binder and an ionically conductive material. Conventionally, as the ion conductive material, a t-electrolyte solution has been used in batteries called wet batteries, and a solid electrolyte has been used in batteries called solid batteries.

Since the positive electrode body of a wet battery contains a solute solution, there is a risk of leakage during use, resulting in poor reliability. To be sure, the positive electrode bodies used in wet batteries are processed into various shapes and mainly use binders that are electrically insulating and insoluble in electrolyte solutions. In order to improve processability, if a large amount of binder is added, the composition ratio of the positive electrode active material decreases as the composition ratio of the binder increases), and the electric density becomes low. Since the positive electrode active material is coated with the binder, the efficiency of use as a battery (hereinafter referred to as discharge efficiency) decreases. Therefore, the positive electrode body cannot contain a large amount of binder, which completely eliminates the disadvantage of poor processability.

Next, the positive electrode body in a solid-state battery entirely contains a solid electrolyte as an ion-conductive material. As a solid electrolyte,
Beta alumina, rubidium silver iodide, lithium nitride,
Lithium iodide alumina, etc. are known, but these materials have drawbacks such as stability at room temperature and ion conductivity 2 standards, and furthermore, when mixed in the positive electrode body - it is difficult to mix uniformly. In addition, the mixture has disadvantages such as poor mechanical workability and is extremely difficult to mold into any desired shape. Furthermore, since the positive electrode active material and the solid electrolyte are in solid contact with each other, the interfacial resistance is large, increasing the internal resistance of the battery. In addition, it has many drawbacks, such as poor discharge efficiency due to the small contact area.

An object of the present invention is to provide a positive electrode body for a battery that addresses the above-mentioned drawbacks.

Specifically, the present invention provides an electrolyte comprising ions of metals belonging to at least one of group 1 or group 1 of the periodic table;
An object of the present invention is to provide a positive electrode body for a battery, which is characterized by containing an ion conductive solid method composition containing an organic polymer compound and an organic solvent that dissolves the electrolyte and the organic polymer compound, and a method for producing the same.

The solid body according to the present invention refers to a body that appears to be in a top-down state under the conditions of use of a battery using the solid body, and is not in the state of a flowing body like a liquid.

The positive electrode body of the present invention obtains high ionic conductivity by using the above-mentioned ion conductive solid composition, and by using an organic polymer compound, 1. is applied to the positive electrode body.

The ion conductive solid composition used in the present invention is based on Japanese Patent Application No. 56-029091, and the combinations of the compositions are shown in the table.

In general, when considering the internal resistance of a battery that can be considered from the discharge efficiency and discharge current of the battery, the higher the ionic conductivity σi of the ion conductive solid composition that constitutes the positive electrode body, the more effective it is. It has been found that σ1 is significantly dependent on the specific electrical conductivity ε of each of the organic polymer compound and organic solvent constituting the ionically conductive solid method composition. When 10 or more organic solvents are combined, the effects of ε of both substances are synergistically significant, and a very high σ1 of a maximum of 1O5-Cm-1 is obtained.

The positive electrode body was constructed using the ionically conductive solid composition shown in the table, and the discharge characteristics of the battery were fully investigated. was. In this way, a more practical battery can be obtained by using an ion conductive solid composition of a combination of an organic polymer compound with ε of 4 or more and an organic solvent with 6 of 10 or more. We have come to the conclusion that the present invention is effective for.

The positive electrode body according to the present invention is entirely solid or made of a solid body, using a solid electrolyte or an ion-conductive circular body composition as a diaphragm, and using a metal belonging to the periodic table genus Oyohi or group Ⅰ for the negative electrode. Therefore, it is possible to make all of the metal components of the cell battery solid or solid. As a result, it is possible to obtain a highly reliable battery without the risk of liquid leakage, like a solid-state battery. In addition, the ionic conductive circular body composition used in this battery is superior to solid electrolytes in terms of ionic conductivity, mechanical workability, cost, etc.
It is possible to obtain a battery that is more practical than conventional solid-state batteries.

The higher the composition ratio (volume %) of the ion conductive circular body composition contained in the positive electrode body, the higher the ionic conductivity of the positive electrode body, the higher the efficiency of use as a battery, and the better the processability. However, on the contrary, the composition ratio of the positive electrode active material decreases, and the electric density decreases, making it impossible to obtain a battery with A1 high energy density. Therefore, the composition ratio of the ionically conductive circular body composition has a maximum limit value for obtaining a practical positive electrode body, and this value varies depending on the combination of each composition. , approximately 60 to 90 volumes, and a composition ratio below this maximum limit value can be put to practical use.

Next, a method for manufacturing a positive electrode body for a battery according to the present invention will be explained. This manufacturing method involves mixing the positive electrode active material, the conductive agent, and the ionic conductive solid composition, which are the components of the positive electrode body, in a nearly liquid state), uniformly mixing each component, and It can be evenly adhered to the surface of the organic polymer compound or electrolyte of all positive electrode active materials. When the organic solvent is removed from this mixture and the composition ratio of the organic solvent falls below a certain level, an ionically conductive solid is precipitated in the positive electrode body, and the mixture assumes a solid state.

This process is effective in increasing the electrical density of the positive electrode body, lowering the internal resistance of the battery, and increasing the efficiency of use of living materials. This is because if the positive electrode body is molded in a paste state and then solidified, the organic solvent in the positive electrode body evaporates, creating pores in the positive electrode body, lowering the density of the positive electrode body, and reducing the electrical density. do.

Furthermore, due to the pores, the internal resistance of the battery increases due to the sparse contact between the particles of the positive electrode body, and the discharge efficiency of the active material decreases. Therefore, a step of partially and completely removing the organic solvent before converting the positive electrode into the Kl type is effective in obtaining a more practical positive electrode.

The present invention will be explained below with reference to Examples.

Example 1] Ion-conductive circular body compositions were used in the combinations shown in the table. Mix an organic polymer compound with an electrolyte solution in which an electrolyte is dissolved in an organic solvent, and thoroughly stir and heat to dissolve. Manganese dioxide (hereinafter referred to as Mn0z), which is a positive electrode active material, and acetylene black, which is a conductive agent, were mixed with this and thoroughly kneaded to form a nearly liquid paste. This pastera is heated at a temperature between 160'O and 160'O, depending on the organic solvent used, and left until the organic solvent is gradually vaporized and the paste is solidified.9. Next, this isomorphic mixture is crushed to form a powder.9.

Next, put this powder into a mold and press it at 2000 kg/am2.
The mixture was pressurized at a pressure of 2 Q mm in diameter, Q in thickness, and formed into a tablet with a thickness of 5 mm to obtain a positive electrode body for a coil-shaped battery.

Next, as a diaphragm for a battery, a membrane of an ion conductive circular body composition having the same combination as the composition of the positive electrode body was prepared according to Example 1 described in Japanese Patent Application No. 56-029091. Cut it out to a diameter of 21mm and prepare.

The negative electrode body was prepared by rolling the same metal as the metal ions of each electrolyte to a thickness Q of 3 mm and punching it into a disk shape with a diameter of 18 mm. These three materials were laminated in the order of positive electrode body, diaphragm, and negative electrode body to form the entire battery.

Although the positive electrode body obtained in this example was as thin as 5 mm, it had excellent mechanical strength) and good moldability. In fact, it is possible to make this positive electrode body even thinner.

Suitable for obtaining thin batteries. Furthermore, no matter which combination of ion conductive circular body compositions that satisfy claim 1 of the table are used, each battery exhibits good characteristics with an initial internal resistance of 20 OKΩ or less. Ta. Furthermore, each battery leaked liquid φ (all<female<) and was highly reliable.

Connect a discharge load resistor of 100 Ω to this battery, and measure the discharge characteristics of the battery using the voltage across the resistor as the battery's electromotive force. The results are shown in FIG. A, B, C in Figure 1
, D are combinations of ionically conductive circular body compositions numbered 2, 3, 12, and 19, respectively. Samples C and D in which the organic polymer compound has a dielectric constant e of 4 or more and the organic solvent has a dielectric constant e of 10 or more; sample A in which the organic polymer compound has an e of less than 4; and the organic solvent has an e of less than 10. When comparing Sample Be, the former has a lower internal resistance of the battery, better flatness of the electromotive force), and is also superior in discharge efficiency. Therefore, in order to obtain a more practical positive electrode body for a battery, an organic polymer compound in which e is 4 or more and an organic solvent in which 6 is 10 or more are used as constituents of the ionically conductive circular body composition. It has been recognized that the present invention is characterized in that it is more effective when a combination of these is used.

[Example 2] Next, nine cases in which the composition ratio of the ion conductive circular body composition in the positive electrode body is changed will be described using a Lithium ion battery as an example.

As the positive electrode active material, MnQ2f was used as in Example 1, and the spacing was 1.
All of the combinations numbered 19 in the 1iKU table were prepared in the same manner as in Example 1.

An organic polymer compound PolyJac1Noronide1 was mixed in a weight ratio of 10:1 into a previously prepared lithium perchlorate (Liclo4)/ethylene carbonate solution with a concentration of 2 mol/l, and the mixture was heated at a temperature of 120'. The mixture was stirred and dissolved while heating to 0.0°C. Next, acetylene brane,
This solution was mixed with MnO2 containing 5% by weight of silica at a weight mixing ratio of 1:2, 2:3, and 1:1, respectively, and each was thoroughly kneaded to form a paste for 7'h. Next, these pastes were placed in a vacuum heating dryer i, heated to
By controlling each depressurization and heating time under the conditions of 30'O and a pressure of 39 mmHg, the composition ratio of each component of the ion conductive circular body composition formed in the paste is made equal; A portion of the organic solvent evaporates and solidifies, and the paste is thoroughly crushed in each mortar to form a powder.

Next, 400 mg of each powder was taken out and made into tablets each having a diameter of 20 mm and a thickness of 0.46°, 0.43°, and 0.4° in the same manner as in Example 1.
Even though all the tablets were very thin, they had strong mechanical strength and were easy to handle.

The negative electrode body was prepared in the same manner as in Example 1, and the positive electrode body, the diaphragm, and the negative electrode body were laminated in this order to form a battery.

The discharge characteristics of these batteries were measured in the same manner as in Example 1.

The results are shown in FIG. E in Figure 2.

The mixing ratios of F and G are 1:2 and 2:3, respectively. The composition ratio of the ion conductive circular body composition in the positive electrode body was 60 and 52.45 volume, respectively, corresponding to 1:t.

When the composition ratio of the ionically conductive material composition in the cathode body is large, the voltage uniformity and discharge efficiency in the discharge characteristics are improved, but the composition of the cathode active material is relatively small. The energy density has decreased. In the case of this example, the composition ratio of the ionic conductive body composition was 75 volume tsk
If it exceeds the limit, the amount of electricity discharged from the positive electrode begins to decrease. Considering the practicality of the battery, the maximum limit value of the composition ratio of the ionic conductive shape-oriented composition was approximately 85 bodies.

[Example 3] The ionic conductivity σ1 of the ionic conductive body composition largely depends on the composition ratio of the organic solvent in its composition. In this example, Mn0zi was used as the positive electrode active material, and number 15 in the table was used as the diaphragm.
Nine cases will be described in which the composition ratio of the organic solvent of the ionically conductive composition in the positive electrode body is varied using a combination of the following.

Mix polyvinylidene fluorite heavy J12gr into 20ml of a lithium perchlorate (Liclo4)/propylene cartanate solution prepared in advance and having a concentration of 2 mol/l, and stir and dissolve while heating to a temperature of 130°C. . This was mixed with 1 sgr of MnO2 and 1 part of acetylene black to obtain a paste. The composition ratio of Li was divided into 13 equal parts and the heating time for each was changed to control the composition ratio. Put these three gold pastes into a vacuum heating dryer. 1 temperature 13'
9 and 10, respectively, under 0"O and 600mmHg pressure.
Leave to stand for 11 hours to vaporize a portion of the organic solvent (paste)
Solidified. This was thoroughly crushed in a mortar to form a powder. Next, a weight of 400 mg'i was taken out from this powder, and a diameter of 29 mm and a thickness of 0.4 mm was obtained in the same manner as in Example 1.
I got a 3mm tablet. This tapere and top also have a thickness of 0.
．． Despite being as thin as 43 mm, it had strong mechanical strength and was easy to handle. The negative electrode body was prepared in the same manner as in Example 1, and the positive electrode body and diaphragm were also prepared in the same manner as in Example 1.

A battery was constructed by laminating the negative electrode bodies in this order.

The discharge characteristics of these batteries were measured in the same manner as in Example 1.
The results are shown in FIG. HlI and J in FIG. 3 are for heating and drying times of 9 and 10.11 hours, respectively, and the composition ratios of organic solvents in the ion conductive solid composition in the positive electrode body are 70 and 62 hours, respectively. .

It was 55% by weight.

The larger the composition ratio of the organic solvent in the ionically conductive solid body composition, the better the discharge characteristics of the battery, which closely matched the characteristics of the ionically conductive body composition. The higher the composition ratio of this organic solvent, the better the discharge characteristics will be, but if the composition ratio exceeds a certain value, the ionically conductive composition in the positive electrode body will not be able to remain in a solid state, and will become like a liquid. As a result, it becomes impossible to obtain a positive electrode body in a solid state, which is a feature of the present invention.

Therefore, the composition ratio of the organic solvent has a maximum limit value, which varies depending on the combination of conductive solid compositions, but is approximately 50 to 90% by weight.

In this example, the composition ratio of the organic solvent contained in the ionically conductive shape-oriented composition in the positive electrode body was controlled by the heat drying time, but it could also be controlled by changing the pressure and temperature during heat drying. In addition, the composition ratio of the electrolyte and organic solvent in the organic polymer compound contained in the ionically conductive composition can be easily controlled when mixing with the positive electrode active material and conductive agent, and It was extremely easy to control each composition ratio.

In Example 1.2, all steps up to battery fabrication were performed in an argon inert gas atmosphere.

In the examples, all solid batteries were prepared and explained using an ionically conductive shape-oriented composition *i for the battery diaphragm. Needless to say, it can also be used in a battery configuration having a solid electrolyte.

In the examples, the positive electrode active material iMno2 was used.
However, the applicable range of the present invention is not limited to M n 0 2 as the positive electrode active material, but also includes titanium oxide (TjOz), steel oxide (Cub), lead oxide (P
metal oxides such as iron sulfide (Fe28), titanium sulfide (TiSz), metal sulfides such as sulfide steel (Cub),
Furthermore, even when a battery was prepared using a material such as an organic compound with large electron donating properties such as tetracyanoquinodimethane or penzoquinone as a positive electrode active material, good battery characteristics similar to those of the example were obtained.

Furthermore, in the examples, three of the positive electrode body, the diaphragm, and the negative electrode body are
Although the description has focused on a simple stacked battery structure consisting of layers, the positive electrode body according to the present invention can be easily molded into a thin sheet shape due to its easy processability and binding properties. A sheet-like battery (sheet or paper battery) is formed by laminating the positive electrode body, diaphragm, and negative electrode body, or a battery with a shishitomo structure in which the laminated sheets are folded, stacked, or rolled. was also easily produced. As a result, a battery capable of drawing a large current proportional to the area of the sheet was obtained.

According to the present invention, a positive electrode body with high ionic conductivity and easy processing can be obtained, and a solid battery without the risk of leakage can be easily obtained.

[Brief explanation of drawings]

1 to 3 show the discharge characteristics of a next battery using the positive electrode body of the present invention. Fig. 1 shows cases in which the compositions of the ion-conductive circular body compositions are varied, and Fig. 2 shows cases in which the composition ratios of the ion-conductive circular body compositions in the positive electrode body are different. FIG. 3 shows the composition ratios of the organic solvents in the ionic conductive body compositions in the positive electrode body. A: An organic polymer compound with a dielectric constant ε of less than 4 B: An organic solvent with an e of less than 10 C and D: An organic polymer compound A combination in which C is 4 or more and C in an organic solvent is 10 or more E...A combination in which the composition ratio of the ion conductive circular body composition in the positive electrode body is 60 by volume F...・ #52 G・・・・・・ #45

Claims (2)

[Claims] (1) Group I of the periodic table te consists of an electrolyte consisting of ions of metals belonging to at least one of the groups II, an organic polymer compound with a dielectric constant of 4 or more, and an organic solvent with a dielectric constant of 10 or more. A positive electrode body for a battery, characterized in that it contains an ion conductive solid composition having the following properties. (2) The organic solvent in which the electrolyte and organic polymer compound were dissolved was mixed with the positive electrode active material and the conductive agent, and then a part of the organic solvent was removed to form the ionically conductive solid composition. A method for producing a positive electrode body for a battery, characterized in that the positive electrode body is then obtained by pressure molding.