JPS6123946B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an ionically conductive solid composition. In particular, polymers have excellent mechanical properties such as ease of molding and forming films into arbitrary shapes, which are inherent to polymers, and also have extremely high ionic conductivity of metals belonging to groups and groups of the periodic table. The present invention also relates to an ionically conductive solid composition. Conventionally, ion conductive materials have mainly been (a) so-called electrolyte solutions in which electrolytes are dissolved in water or organic solvents, and (b) beta alumina β-.
Al ₂ O ₃ , lithium iodide/alumina LiI−Al ₂ O ₃ ,
Solid electrolyte materials made of inorganic substances such as silver rubidium iodide RbAg ₄ I ₅ are known. Ionic conductive materials are used in a wide variety of industrial fields, but examples of their use as electronic components include primary batteries, secondary batteries, electrolytic capacitors, sensors, electromic display elements, and on electrodes. It is widely used as a material for electronic components, such as by depositing metal and detecting the integral value of electrical quantity, such as as a time-limiting element or an integral memory element. In recent years, in the field of electronics industry, not only high performance and miniaturization of electronic devices, but also high performance, small and thin electronic components, and high reliability as components are required. The first requirement for highly reliable electronic components is that the material used in the component must be a solid body, that is, an object that appears solid under the conditions in which the component is used, and that flows like a liquid (hereinafter referred to as a fluid). (hereinafter referred to as a solid body). This is because when a fluid material is used in an electronic component, fluid often leaks from the inside of the component to the outside of the component. This leads to a deterioration in the performance of the electronic component and has an adverse effect on other electronic components near the electronic component, which ultimately causes the electronic device to malfunction. Therefore, when used as an ion conductive material in an electronic component, it can be said that an electronic component using a solid ion conductive material is more reliable than a fluid one. On the other hand, in order to obtain highly reliable parts using fluid ion-conductive materials, there are ways to make the parts completely airtight, but these end up resulting in expensive electronic parts that are often impractical. . Among the above-mentioned ion conductive materials, the electrolyte solution (a) is a fluid and therefore has high reliability for the reasons mentioned above, but has the disadvantage that it cannot be used for inexpensive electronic components. On the other hand, the above-mentioned solid electrolyte material (b) has the advantage of being compatible with highly reliable electronic components because it is a solid body. However, there are very few solid electrolyte materials that have high ionic conductivity, and most solid electrolyte materials have low ionic conductivity. Moreover, in order to obtain a solid electrolyte with high ionic conductivity using an inorganic compound, it is necessary to make full use of reaction operations that are considered extremely difficult, so there are currently very few practical examples. Furthermore, since the solid electrolyte material of Olowa is a composition of inorganic compounds, it is extremely difficult to mold it into an arbitrary shape or form it into a film. That is, solid electrolytes made of inorganic compounds have the disadvantage of poor mechanical properties such as ease of processing and forming films into arbitrary shapes. For this reason, it has the disadvantage that the fields in which it can be used as an ion-conductive material are extremely limited. Electrolyte solution of the above-mentioned ion conductive material (a) and (b)
As an intermediate form of solid electrolyte,
For example, there is an ion conductive material that is used in dry batteries and is made by kneading an aqueous electrolyte solution with an aqueous starch solution to form a paste. Even though they are glue-like, under practical usage conditions they take on a form similar to that of a fluid, so in dry batteries, for example, paper or non-woven fabric is used as a separator to prevent short circuits between the anode active material and the cathode active material. Must. In reality, the separator separates the active materials of both electrodes and contains a glue-like ion-conductive material, so it can be used in the same way as a fluid such as an electrolyte solution. Even with glue-like ion-conductive materials, (a) fluid leakage occurs frequently, as seen in normal dry batteries, and reliability is poor. (b) Since it cannot be molded into any shape or formed into a film, it has the disadvantage that its applicable fields are extremely limited. If the aqueous solvent is removed by evaporation to an extent that does not cause liquid leakage, molding and film formation will not be impossible, but in this case, the ionic conductivity will drop significantly and it cannot be put to practical use. Furthermore, when water is used as a solvent, there are the following drawbacks. (i) Water reacts electrochemically with most metals and corrodes them. Therefore, when applied, there is a drawback that the metal materials that come into contact with the water-containing ion conductive material, such as the metal materials for the electrode parts and the parts that seal the electronic elements, are extremely limited. (ii)
The decomposition voltage of water is approximately 1.2V, which is generally lower than that of organic solvents, and cannot be used at voltages higher than the decomposition voltage. (iii) Ion conductive materials containing water have a high and stable ionic conductivity whose use temperature is limited to a range near the freezing point (0°C) and boiling point (100°C) of water, and at other temperatures. unable to maintain. (iv) In ionic conductive materials containing water, H ⁺ and OH ^- generated by ion dissociation of water also function as conductive carriers, and if you want to use only metal ions as conductive carriers, the number of carrier species will continue to increase. Instead, it forms an extremely complex conductive mechanism by ionically bonding with metal ions. For this reason, the ionic conductivity becomes unstable, making it unsuitable for use in, for example, a timing element or an integral memory element to detect an integral value of capacitance. The object of the present invention is to create a new ion-conductive material that solves these conventional drawbacks, that is, an ion-conductive solid material that has both high ion conductivity and excellent mechanical properties such as ease of processing and forming films into arbitrary shapes. An object of the present invention is to provide a composition. According to the present invention, it is possible to obtain an ion-conducting solid composition comprising an electrolyte comprising a metal ion belonging to a group of the periodic table and/or a group, an organic polymer compound, and an electrolytic organic solvent having a dielectric constant of 10 or more. . The first feature of the present invention is that the ionically conductive solid composition contains an organic solvent in order to eliminate the conventional drawbacks, particularly the many drawbacks mentioned above that appear when water is used as a solvent. If an organic solvent is applied,
() It is stable with very little chemical reaction with various metal materials. () The decomposition voltage of organic solvent is higher than the decomposition voltage of water, which is 1.2V. () If an appropriate solvent is selected, the usable temperature range will be wider than in the case of water. () Very few organic solvents, like water, dissociate into H ⁺ and OH ^- ions and have a negative effect. For the reasons mentioned above, the use of organic solvents has the advantage of being able to construct ion conductive materials that are more stable and can be used in a wider range of applications than conventional aqueous solvents. On the other hand,
The ionic conductivity σi tends to be lower than when a water solvent is used. Generally, σi increases in proportion to the product of the concentration ni of the carrier ion species and its mobility μi. Therefore, as an organic solvent effective for increasing σi, (A) dissolves the electrolyte in high concentration and
It is desirable to use an organic solvent that contributes to an increase in (B) the electrolyte and also dissolves not only the electrolyte but also the organic polymer compound well to make the distribution of ions uniform and increase the mobility of the ions. Therefore, the organic solvent is not limited to one type, and a mixed solvent of two or more types may be used. In this way, the organic solvent functions as a material for preparing a solid composition by dissolving electrolytes and organic polymers, and ultimately remains in the solid composition to express ionic conductive function. It is also an important constituent of ionically conductive solid compositions. From the above viewpoint, as a result of detailed study on organic solvents that are effective in the present invention, it was found that the dielectric constant ε of the organic solvent has a very large effect on the expression of ionic conductivity. When the relationship between σi and ε was investigated in detail for many types of organic solvents having different dielectric constants ε, the results shown in the table were obtained. As is clear from the table, σi tends to increase as the ε of the organic solvent increases. here,
Considering various application fields as an ion conductive material, the larger σi is, the wider the field it can be used.
as the minimum value of i and at least 10 ^-10 S cm ^-1
If the above σi is within the range that can be applied and provided. Therefore, when determining ε of an organic solvent that exhibits ionic conductivity with σi of approximately 10 ^-1 S cm ^-1 or more, we find that in an organic solvent system with ε of approximately 10 or more, σi is 10 ^-9 S cm -1 or more.
For organic solvent systems with cm ^-1 or more and ε of about 20 or more, σi is about 10 ^-8 S・cm ^-1 or more, especially for organic solvent systems with ε of about 30 or more, σi is about 10 ^-7 to 10 ^-6 S・cm
^-1 high ionic conductivity was observed. From the above results, considering the possibility of application as an ion conductive material, the effect of organic solvent on σi is ε.
Looking at the effectiveness of , it can be seen that if ε is 10 or more, it satisfies the requirements for an organic solvent included in the composition. If the ε of the organic solvent increases,
The dissociation of ions in the electrolyte is promoted, increasing the solubility of the electrolyte, and the solubility of highly polar organic polymer compounds is also excellent. distribution becomes uniform, contributing to an increase in ion mobility. As a result, the larger the ε of the organic solvent, the more it satisfies the above-mentioned requirements (A) and (B) for the organic solvent to be effective in increasing σi. The effect is ε10
It was expressed above, and particularly when ε was 30 or more, it was expressed markedly, and a composition was also obtained which exhibited a very high σi of about 10 ⁻⁶ S·cm ⁻¹ . Organic solvents with large ε are generally used with highly polar bonding groups (which are called polar groups) that are composed of atomic groups such as oxygen atoms O, nitrogen atoms N, sulfur atoms S, and halogen atoms in addition to carbon atoms C. ), and the more this polar group is arranged in a molecular structure that is more easily polarized, the larger ε becomes. In the table of examples, compounds such as alcohols, ketones, amides, nitriles, and carbonates are shown as examples, but the compounds are not limited to these compounds, and ε
The effects of the present invention can be obtained with any organic solvent having a high polarity of 10 or more. The second feature of the present invention is that the ionically conductive composition contains an organic polymer compound. This is expected to result in the ability to form into arbitrary shapes and form films by imparting excellent mechanical processability inherent to organic polymer compounds. There is also a method of using an organic polymer compound simply as a binder, but in this case there is a certain limit to the improvement of ionic conductivity. That is, the presence of organic polymers tends to act as a steric hindrance when ions move, resulting in a decrease in the ion mobility μi. Therefore, in order to remove this obstacle to the movement of ions, the inventors came up with the idea of impregnating organic polymers with an organic solvent that has excellent solubility for organic polymers, thereby making them swollen. .
When the organic polymer is in a swollen state, the distance between the organic polymers is relatively expanded, allowing ions to move freely. Furthermore, the interaction between ions and organic polymers is relaxed, and ion mobility is greatly improved. As the content of the organic solvent increases, the distance between the organic polymers becomes wider and the organic polymers are completely dissolved to reach a solution state. In a flowing state, it becomes a liquid and cannot be molded into a certain shape. Therefore, in order to maintain a constant solid state, it is necessary to specify the maximum content of organic solvent contained in the solid composition; It varies depending on the solubility of the polymer compound, as well as the molecular weight and molecular weight distribution of the organic polymer compound. As a result of examining the effective compounds of the present invention for various organic polymer compounds, we found that when using an organic solvent with σ of 10 or more, not only thermoplastic resins but also phenolic, urea-melamine, and polyester-based , thermosetting resins such as polyurethane-based, epoxy-based, diene-based such as polybutadiene, polyisobutylene, and chloroprene, polysulfide-based such as acrylic rubber, urethane rubber, thiol rubber, silicone rubber-based, and fluorine-based rubber. Elastic bodies also gave relatively good results. This is because when an organic solvent with a high dielectric constant with ε of 10 or more is used, the high polarity of the organic solvent causes the formation of highly polar organic polymer compounds, as well as network formations such as those found in thermosetting resins and rubber elastic materials. This is due to the fact that it can easily swell and dissolve even organic polymer compounds with this structure. Particularly effective were thermoplastic resins. For example, vinyl resins such as polyvinyl chloride and polyvinyl acetate, acetal resins such as formal resin and butyral resin, acrylic resins such as acrylic resin and methacrylic resin, styrene resins such as polystyrene and ABS resin, polyethylene and polybutene. Olefin resins such as olefin resins, as well as polyamide resins, gave relatively good results. Therefore, in the examples described below,
Although thermoplastic resins were mainly studied as an example of the organic polymer compound, the effects of the present invention are also recognized with other thermosetting resins and rubber elastic bodies. A third feature of the present invention resides in the composition of an ionically conductive solid composition containing, as an electrolyte, a salt consisting of ions of metals belonging to groups and/or groups of the periodic table. In order to exhibit high ionic conductivity, it is necessary for the metal salt to have low ionic dissociation energy and to have excellent solubility in organic solvents. As a result of examining effective electrolytes for the present invention from this point of view, it was concluded that salts consisting of ions of metals belonging to groups and/or groups of the periodic table are particularly effective. The larger the electrolyte content in the solid composition, the more it contributes to increasing the electrical conductivity, but if it is present in a large amount, the composition becomes hard and brittle, and mechanical workability decreases. Further, the larger the amount of solvent contained in the solid composition, the greater the mobility of ions and the higher the electrical conductivity, but if the solvent is present in a large amount, the composition will soften and eventually become a fluid. Therefore, there is a practical maximum value for the electrolyte and solvent contents. In addition, although this maximum value cannot be uniformly determined depending on the type and physical properties of the compounds that make up the solid body composition, as a result of various experiments, the maximum value of the electrolyte content is determined by the repeated use of organic polymer compounds. The organic solvent content was approximately 70 to 90 mo% relative to the unit, and the maximum organic solvent content was approximately 50 to 90 wt% of the solid composition. Examples of the present invention will be described below. In addition, the content of the electrolyte and solvent in the ion conductive solid composition was carried out on samples within a range that did not exceed the above-mentioned maximum values. [Example] An electrolyte solution in which an electrolyte was dissolved in an organic solvent and a polymer solution in which an organic polymer compound was dissolved in an organic solvent were prepared. The prepared electrolyte solution and polymer solution were mixed and sufficiently stirred until uniform. If it is difficult to obtain a uniform solution, a predetermined uniform solution can be obtained by stirring the mixed solution while heating it. after that,
The mixed solution was decompressed and degassed using a rotary pump. Next, a certain amount of this mixed solution was poured into a Teflon container prepared in advance, and the organic solvent was gradually evaporated while flowing nitrogen gas at a temperature from room temperature to below the boiling point of the organic solvent. This operation was continued until the sample in the Teflon container changed from a solution state to a gel state. After the sample was in a gel state, the Teflon container containing the sample was transferred to a vacuum heating dryer and heated and dried under normal pressure at a temperature below the boiling point of the organic solvent used while flowing nitrogen gas. In addition, when the boiling point of the organic solvent was 100° C. or higher, it was dried by heating under reduced pressure. The heating and drying was continued until the sample changed from a gel state to a state that did not deform even if the container was tilted, that is, a solid state. After heating and drying, the Teflon container containing the sample was transferred into a glove box filled with nitrogen gas, and the sample was peeled from the Teflon container and cut into a certain shape. The cut sample piece was sandwiched between platinum black electrodes in the shape of a sandwich, and the resistance value of the sample piece was measured using the alternating current two terminal method. The measurement was performed in a nitrogen gas atmosphere at a frequency of 1 KHz, and the conductivity σ of the sample was calculated from the resistance value, thickness, and area of the platinum black electrode of the sample piece. Combinations of compounds constituting the ionically conductive solid composition sample, that is, organic polymer compounds, organic solvents with different dielectric constants σ, and electrolytes, were conducted using the sample preparation procedure and measurement method described above. ,
The ionic conductivity σi of the solid composition formed by this combination is shown in the table. In addition to the combinations of compositions listed in the table, there are also combinations in which the organic polymer compound does not completely dissolve in the organic solvent, but partially dissolves or partially dissolves in the organic solvent, and organic polymer compounds that swell. Although some of the salts were not completely dissolved in the organic solvent, some were dissolved, and others were not dissolved, but this did not affect the effects of the present invention such as sample preparation, moldability, and conductivity, so it was applied in this example. did. In addition, as a result of measuring the electronic conductivity of all samples, the electronic conductivity was approximately 10 ^-14 S cm ^-1 or less, so the conductivity σ by the measurement method described above was changed to the ionic conductivity σ
It is shown in the table as i.

【table】

[Table] As is clear from the table, it was observed that as the ε of the organic solvent contained in the ionically conductive solid composition increases, the σi increases. In other words, phenol with an organic solvent ε of 9.8 (sample No.
5) shows a low σi value of approximately 10 ^-10 S cm ^-1 , but on the other hand, sample systems with organic solvent ε of 10 or more (sample
No. 6 onwards), the dielectric constant of all organic polymer compounds is approximately 10 ^-9 S・cm even though the dielectric constant is less than 4.
Indicates σi of ^-1 or more. In particular, when the ε of the organic solvent is 20
If the value is above, the σi will be approximately 10 ^-1 cm ^-1 or more, and if the ε of the organic solvent is 30 or more, the σi will be 10 ⁸ ~
10 ^-6 S cm ^-1 σi. σi of solid body composition
In addition to the ε of the organic solvent, it is also affected by the type of organic polymer compound and electrolyte that make up the composition, but even when the organic polymer compound and electrolyte are the same, the solid composition It is clear from the results in the table that σi increases as ε of the organic solvent increases, and the effect of the present invention can be understood. Further, the ion conductive solid composition system obtained by the present invention can be formed into any shape or formed into a film depending on the volume and concentration of the solution to be prepared and the shape of the container into which the solution is injected. You can also do that. For example, by reducing the concentration of the prepared solution and reducing the amount of solution injected into a Teflon container, it was possible to form a highly flexible thin film with a thickness of 100 μm or less over a wide area. If the film can be made thin, the resistance in the cross-sectional direction of the film decreases in proportion to the film thickness and inversely to the area, so it can be used in a wide range of applications. In addition, if the film thickness and area are controlled based on σi in the table, the ion conductive composition according to the present invention can be used for batteries, electrolytic capacitors, sensors, electromic devices,
In addition, it goes without saying that it can be used in electronic components using ion-conductive materials, such as time-limiting elements and integral memory elements.

Claims (1)

[Claims] 1. An electrolyte consisting of ions of metals belonging to a periodic table group and/or group, an organic polymer compound with a dielectric constant of less than 4, and a dielectric constant having excellent solubility in the electrolyte and the organic polymer compound.
An ion conductive solid composition comprising 10 or more organic solvents, wherein the content of the organic solvent contained in the solid composition is at least an amount that causes the organic polymer compound to be in a swollen state, and 90wt% or less of the solid body composition, and the electrolyte content is approximately
An ion conductive solid composition characterized in that the amount is selected to be at least an amount that provides an ionic conductivity of 10 ^-8 S·cm ^-1 or more and at most 90 mo% of the solid composition.