JPS6361725B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to ionically conductive solid compositions.
In particular, it relates to an ionically conductive solid composition that has both the excellent mechanical properties inherently possessed by polymers and high ionic conductivity.

Conventionally, ion conductive materials include (a) an electrolyte solution in which an electrolyte is dissolved in water or an organic solvent, and (b) beta-alumina β-Al ₂ O ₃ , lithium iodide-alumina LiI-Al ₂ O ₃ , and iodine. Solid electrolyte materials made of inorganic substances such as silver rubidium RbAg ₄ I ₅ lithium nitride Li ₃ N are known.

In recent years, there has been a strong demand for electronic components to have high performance, small size, and thinness, as well as high reliability, and this has led to active material development. These materials not only have high performance potential, but also
Excellent mechanical workability, flexibility, and strength are required, and solid or solid materials are also strongly required from the viewpoint of high reliability.

The electrolyte solution described in (a) above is used in various electronic components because it has high ionic conductivity, but because it uses liquids such as water or organic solvents, there is a risk of leakage to the outside of the electronic components. There is always the problem of liquid, and this liquid leakage may cause performance deterioration of the component or damage to surrounding components, making the component lacking in high reliability. Furthermore, since it is a fluid ion-conductive material, it lacks mechanical strength, resulting in poor mechanical workability, and the parts have drawbacks such as limited shapes.

On the other hand, since the solid electrolyte material (b) is solid, it is suitable for highly reliable and long-life electronic components, and has been actively developed in recent years in response to demands for smaller and thinner components. However, at present, the ionic conductivity at room temperature is not as high as that of the electrolyte solution (a), which greatly limits the conditions under which the parts can be used. In addition, solid electrolyte materials have drawbacks such as high prices and poor mechanical workability, such as the inability to form into arbitrary shapes or form films, so they have not been put into widespread practical use. .

In order to improve the drawbacks of these conventional ion conductive materials, there are ion conductive materials in the form of paste or gel, which can be said to be an intermediate form between (a) and (b). However, even with paste-like or gel-like materials, the risk of liquid leakage to the outside of the component cannot be completely eliminated, and a drawback still remains in terms of high reliability. Furthermore, in terms of mechanical workability, it cannot be said that it has improved much because, like liquids, it lacks mechanical strength.

In contrast, the inventors have discovered a solid material, i.e., an ionically conductive solid composition that, under conditions of use, becomes an object that appears to be in a solid state but not in a fluid state like a liquid. This is mainly composed of three components: an organic polymer compound, an organic solvent, and an electrolyte. Moreover, since it is a solid material, it can be said that it is a material that is sufficiently better in terms of reliability than paste-like or gel-like materials.

However, there are a large number of combinations of these three components, and there are restrictions on the combinations that satisfy the conditions for practical use as electronic components. For example, if an ionic conductive solid composition has sufficient mechanical workability, it has the disadvantage that its ionic conductivity is considerably lower than that of an electrolyte solution, making it impractical; If it has, it has the disadvantage of poor mechanical workability.

An object of the present invention is to eliminate such conventional drawbacks and to provide an ion conductive solid composition having both higher mechanical processability and higher ionic conductivity.

According to the present invention, the organic polymer compound is polyvinylidene fluoride, the organic solvent is gamma-butyrolactone,
An ionically conductive solid composition characterized in that the electrolyte consists of lithium perchlorate is obtained.

Generally, the ionic conductivity, mechanical workability, and strength of an ionically conductive solid composition are influenced by the composition and concentration of the organic solvent and electrolyte contained therein. As a result of detailed studies on the above compositions effective in the present invention from the above viewpoints, it has been found that the following composition and concentration ranges give particularly good results.

That is, the composition of gamma butyrolactone is 10
-50 parts by weight, and the concentration of lithium perchlorate relative to gamma-butyrolactone was in the range of 1 to 8 mol/.

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

Example 1 This example describes the composition of gamma-butyrolactone contained in an ionically conductive solid composition.

5 grams of polyvinylidene fluoride, an organic polymer compound, was added to 100 ml of gamma-butyrolactone, an organic solvent, heated to a temperature of 120° C., and thoroughly stirred to dissolve.
To this solution, add a predetermined amount of lithium perchlorate so that the electrolyte concentration with respect to gamma butyrolactone in the obtained ionically conductive solid composition is 3 mol/10 ml, and stir and dissolve by heating to a temperature of 100°C. An electrolyte solution was prepared. After pouring this electrolyte solution into a glass shear dish with a horizontal bottom and a diameter of 10 cm, it was placed in a vacuum heating dryer and heated to a temperature of 140.
The gamma-butyrolactone was evaporated by controlling the drying time at a reduced pressure of 300 mmHg at a temperature of 300 mmHg to form an ion-conductive solid composition having a predetermined composition.
As a result of the above operations, the electrolyte concentration for the remaining gamma-butyrolactone is 3 mol/gamma-butyrolactone, the composition of gamma-butyrolactone is 5 to 60 parts by weight, and the film thickness is 0.1
A uniform thin film sample of ~0.2 mm was obtained.

Next, this sample was punched out into a disc shape with a diameter of 10 mm.
This was sandwiched between platinum black electrodes and the electrical resistance of the sample was measured using alternating current at a frequency of 1 KHz, and the electrical conductivity of the sample was calculated from the area between this electrical resistance and the thickness of the sample. These results are summarized in FIG. 1, which shows the correlation between the composition ratio of gamma-butyrolactone and the ionic conductivity of the ion-conductive solid composition according to the present invention.

As shown in FIG. 1, the ionic conductivity increases as the composition ratio of gamma-butyrolactone increases. However, as the composition ratio increases, the mechanical strength of the sample decreases, and the sample changes from a solid state to a paste-like state and loses the characteristics of the present invention. Moreover, if the composition ratio becomes low, high ionic conductivity cannot be obtained and it becomes impossible to put it into practical use. Therefore, the composition ratio of gamma-butyrolactone in the ionically conductive solid composition has a practical range. In the ion conductive solid composition of the present invention, if gamma butyrolactone is in the range of 10 to 50 parts by weight, a good ion conductive material having excellent mechanical strength and processability as well as high ionic conductivity can be obtained. Obtained.

Example 2 This example describes the concentration of lithium perchlorate relative to gamma-butyrolactone in an ionically conductive solid composition. Add 5g of polyvinylidene fluoride to 100ml of gamma butyrolactone,
The mixture was heated to a temperature of 120°C and sufficiently stirred to dissolve. For 10ml of this solution, the concentration of lithium perchlorate in the formed ionically conductive solid composition is 0.5~
After adding a predetermined amount of lithium perchlorate to the solution to give a concentration of 10 mol/liter, the mixture was heated to 100° C., stirred, and dissolved to obtain an electrolyte solution. The following manufacturing method is performed according to Example 1. Approximately 30 parts by weight of gamma butyrolactone remained after the above operations.
A uniform thin film sample with a lithium perchlorate concentration of 0.5 to 10 mol/and a film thickness of about 1.15 mm was obtained.

Using this sample, the conductivity was calculated in the same manner as in Example 1, and FIG. 2 shows the correlation between the concentration of lithium perchlorate in the ion conductive solid composition according to the present invention and the ionic conductivity.

As shown in FIG. 2, the ionic conductivity increases as the concentration of lithium perchlorate increases. However, as the concentration increases, the mechanical strength and workability of the sample deteriorate, and as the concentration increases further, lithium perchlorate becomes supersaturated with respect to gamma-butyrolactone and precipitates, resulting in a decrease in ionic conductivity. Further, if the concentration is low, high ionic conductivity cannot be obtained and it becomes impossible to put it into practical use. Therefore, there is a practical range for the concentration of lithium perchlorate as well as the composition ratio of gamma-butyrolactone. In the ion conductive solid composition of the present invention, lithium perchlorate is 1 to 1 to gamma butyrolactone.
If the concentration is in the 8 mol/concentration range, a good ionically conductive solid composition with sufficient mechanical strength and processability and high ionic conductivity can be obtained even in a thin film like the one in this example. Obtained.

In Examples 1 and 2, the preparation of the ion conductive solid composition and the measurement of the ion conductivity were performed in an argon inert gas atmosphere.

Due to its excellent mechanical processability, the ion conductive solid composition according to the present invention can be used to form very thin films of several microns or large area films using film forming techniques such as pressing or rolling. Ta. In addition, due to their thinner films, larger areas, and high ionic conductivity, they can be put to practical use as ion conductive materials for various electronic components such as batteries, electrolytic capacitors, sensors, electrochromic devices, and time-limiting devices and integral memory devices. It is something that can be provided.

As described above, according to the present invention, it is possible to obtain an ion-conductive solid composition that has excellent mechanical workability, strength, and high ionic conductivity.

[Brief explanation of drawings]

Figure 1 is a correlation diagram between the ionic conductivity σ _i of the ion conductive solid composition according to the present invention and the composition ratio (wt%) of gamma-butyrolactone as an organic solvent, and Figure 2 is a correlation diagram between the ionic conductivity σ _i and the electrolyte excess. Concentration of lithium chlorate to gamma-butyrolactone (mol/)
It is a correlation diagram with.

Claims (1)

[Scope of Claims] 1. An ionically conductive solid composition comprising polyvinylidene fluoride, gamma butyrolactone, and lithium perchlorate. 2 The composition of the gamma butyrolactone is 10 to 50
The ion conductive solid composition according to claim 1, wherein the ion conductive solid composition is in parts by weight. 3. The ionically conductive solid composition according to claim 1, wherein the concentration of the lithium perchlorate relative to the gamma-butyrolactone is 1 to 8 mol/.