JP3384173B2 - Polymer solid electrolyte - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion conductive polymer solid electrolyte. More specifically, the present invention is a polymer solid electrolyte having an organic polymer as a structural material, and exhibits high ionic conductivity by containing an alkali metal ion-based conductive carrier such as lithium ion. And a polymer solid electrolyte having excellent film-forming properties, flexibility and mechanical strength.

[0002]

2. Description of the Related Art When an all-solid-state battery is constructed by using a solid electrolyte, leakage of the contents in the battery, which is one of the problems of conventional batteries, is eliminated, and the safety and reliability of the battery is improved. improves. Further, it is possible to make the battery thinner and stack it.
Therefore, solid electrolytes are drawing attention as materials for batteries and other electrochemical devices.

By the way, the properties required for a solid electrolyte are generally (a) high ionic conductivity and no electronic conductivity, and (b) excellent film-forming property so that it can be thinly formed. , (C) excellent flexibility, and the like.

Further, the types of solid electrolytes are roughly classified into two types, that is, an inorganic material and an organic material. Among them, the solid electrolyte made of an inorganic material has relatively high ionic conductivity, but since it is a crystalline body, it has poor mechanical strength and is difficult to process into a flexible film. There are significant disadvantages when applied.

On the other hand, a polymer solid electrolyte made of an organic polymer can be formed into a thin film having flexibility, and the formed thin film is excellent in flexibility inherent to the polymer. It becomes possible to impart mechanical properties. Therefore, the thin film made of the polymer solid electrolyte can be more flexibly adapted to the volume change caused in the ion-electron exchange reaction process between the electrode and the polymer solid electrolyte, as compared with the inorganic solid electrolyte. For these reasons, polymer solid electrolytes are regarded as promising as solid electrolyte materials for high energy density batteries, especially thin high energy density batteries.

Heretofore, as such a polymer solid electrolyte, polyethylene oxide having a polyether structure [(-CH ₂ CH ₂ O-) _n : hereinafter abbreviated as PEO] is used.
It is known that a complex of Li and an alkali metal salt such as Na salt shows relatively high alkali metal ion conductivity. Further, various polymer solid electrolytes including this complex are being actively researched theoretically on the mechanism of ionic conduction and molecular structure, or applied to electrochemical devices such as batteries.

By the way, the ionic conductivity in the polymer solid electrolyte is that the alkali metal ion in the polymer matrix is selectively ionized in the amorphous portion in the polymer matrix and interacts with the coordinating atom in the polymer. However, it is thought to be achieved by diffusively moving along the electric field in the matrix. For example, in a composite film composed of PEO and an alkali metal salt, when the alkali metal ion interacts with oxygen of an ether bond part having a high dielectric constant in the PEO main chain, ionic conduction occurs due to the segment motion of the molecular chain due to heat. It is considered. Therefore, in order to improve the ionic conductivity of the solid polymer electrolyte, it is considered effective to suppress the crystallinity of the solid polymer electrolyte.

[0008]

However, the conventional polymer solid electrolytes have a problem that the film formability and flexibility are deteriorated when the ionic conductivity is improved by suppressing the crystallinity. Have In addition, there is a problem that the ionic conductivity at room temperature is generally smaller than that of a solid electrolyte made of an inorganic material.

For example, in the case of a composite film of PEO and an alkali metal salt, when the molecular weight of PEO is about 10,000, the film forming property is excellent, and the ionic conductivity is 10 ⁻³ to 10 ⁻⁴ at 100 ° C. or higher. It has a relatively high value of about S / cm. However, since this composite film is crystalline,
The conductivity drops sharply at the following temperatures, and at room temperature,
^It shows a very low value of about ^-7 S / cm or less. For this reason, it is impossible to incorporate it as a material for a normal battery having a room temperature as an operating temperature range.

Therefore, the formula (i)

[0011]

[Chemical 2] As shown in the formula (n is an arbitrary integer), the crystallinity of the composite film is suppressed by reacting the terminal hydroxyl group of PEO with diisocyanate to form urethane crosslinks or ester crosslinks. Attempts are being made. This crosslinked structure is effective as a means for improving the mechanical properties without significantly reducing the ionic conductivity of the amorphous polymer. However, sufficient results have not been obtained even with such means.

On the other hand, by setting the molecular weight of PEO, which is an organic polymer constituting the composite film, to 10,000 or less, the ionic conductivity near room temperature can be improved, but in this case, the film forming property is remarkably increased. It becomes difficult to form a film.

Further, when the content concentration of the alkali metal salt is increased in order to improve the ionic conductivity, the glass transition point Tg of the composite film also rises, which lowers the ionic conductivity. I will end up. Thus, it is not possible to simultaneously achieve an increase in the density of the carrier body and an increase in the conductivity.

Another example of the solid polymer electrolyte is a compound similar to the above-mentioned complex composed of PEO and an alkali metal salt, and has the formula (ii):

[0015]

[Chemical 3] (Wherein R is H or CH ₃ and m and n are arbitrary integers), an acrylic or methacrylic organic polymer having a PEO structure in the side chain is known. ing. Also, the formula (iii)

[0016]

[Chemical 4] (Wherein, m and n are each arbitrary integers), the side chain has a PEO structure, and the main chain has (-P =
N-) _m polyphosphazene-based organic polymer,
Formula (iv)

[0017]

[Chemical 5] (Wherein, m and n are each an arbitrary integer), the side chain has a PEO structure, and the main chain is (-Si).
A siloxane-based organic polymer composed of O-) _m is known.

The ionic conductivity of the polymer solid electrolyte composed of these organic polymers and alkali metal salts is -10 ^-5 S /
cm, which is slightly improved as compared with the composite film composed of PEO and an alkali metal salt, but is still insufficient in practical use, and the film formability and flexibility are also sufficient. Not not. Therefore, a battery using a conventional polymer solid electrolyte has not been obtained that has practically sufficient battery performance.

On the other hand, in addition to the above-mentioned organic polymer and metal salt, a polymer solid electrolyte has been developed which further contains an organic solvent compatible with these organic polymer and metal salt. In this solid polymer electrolyte, the organic polymer has a gel swollen in an organic solvent, without using an organic solvent so far solid polymer electrolyte very high compared to the quality to 10 -3 S ^/ cm It is possible to obtain a degree of conductivity.

As for the organic polymer which constitutes the polymer solid electrolyte containing the organic solvent as described above, the above-mentioned formula (i
In addition to using organic polymers such as i) to (iv), it has been attempted to use those obtained by crosslinking these by irradiation with actinic radiation, light irradiation, electron beam irradiation, heating or the like. further,
Attempts have also been made to use a fluororubber-based crosslinked product, an acryl-nitrile-butadiene-based crosslinked product, or a urethan crosslinked product as an organic polymer using a crosslinking agent. By cross-linking the organic polymer in this way, even though the organic polymer swells in the organic solvent and becomes a gel, stains of the organic solvent when pressure is applied to the polymer solid electrolyte The protrusion can be suppressed, and the mechanical strength can be improved.

However, even in a solid polymer electrolyte containing an organic solvent, its electric conductivity is lower than that of an ordinary electrolytic solution, and it is desired to further improve the electric conductivity, and mechanical strength is also improved. It was desired to let them do it.

The present invention is intended to solve the problems of the prior art, has high ionic conductivity comparable to that of an electrolytic solution even at around room temperature, and has excellent film-forming property, flexibility and mechanical properties. The purpose of the present invention is to obtain a new polymer solid electrolyte having specific strength.

[0023]

The inventors of the present invention have found that an organic polymer having a polyalkylene carbonate unit in which a carbonate group and a methylene chain are bonded to each other in a main chain contains a functional group capable of appropriately interacting with a carrier ion. Therefore, it is possible to contain carrier ions at a higher density than conventional organic polymers, and it is difficult to crystallize even at low temperatures, so it is possible to secure sufficient segment motion by maintaining the amorphous state. Moreover, it was found that there is a characteristic that electron conduction does not occur. Furthermore, by swelling an organic polymer having a unit in which a carbonate group and a methylene chain are bonded to the main chain into an organic solvent, it was found that high ionic conductivity comparable to that of a conventional electrolytic solution can be obtained. It was found that the above object can be achieved by using as a structural material of a polymer solid electrolyte,
The present invention has been completed.

That is, the present invention provides the following equation (1)

[0025]

[Chemical 6] Provided is a polymer solid electrolyte comprising an organic polymer having a unit of the formula (n is an integer), a metal salt, and an organic solvent compatible with the organic polymer and the metal salt.

The present invention will be described in detail below.

In the polymer solid electrolyte of the present invention, an organic polymer having a polyalkylene carbonate unit of the above formula (1) in its main chain is used as an organic polymer serving as its structural material. In the unit of this formula (1), a methylene chain (CH ₂ )
_n may be linear or branched. Also,
The _n of the methylene chain (CH ₂ ) _n is not particularly limited, but is preferably 2 or more from the viewpoint of molecular stability. However, if the methylene chain becomes too long, it becomes difficult to synthesize, and
Since the dielectric constant decreases and the compatibility with the metal salt decreases, n
Is preferably 10 or less, and particularly preferably 6 or less. Therefore, as a preferable specific example of the unit of the formula (1),
For example, those shown in Table 1 can be mentioned.

[0028]

[Table 1] The organic polymer having such a unit may have a single type of unit or may have a plurality of types.

The average molecular weight of the organic polymer in this case depends on the structure of the unit of the organic polymer, but if the average molecular weight is too low, the film-forming property is deteriorated and the organic polymer is swollen. It is difficult to form a film, and on the other hand, if it is too high, it becomes difficult to dissolve or swell in an organic solvent. Therefore, it is usually preferably about 1 × 10 ³ to 1 × 10 ⁶ .

The method for producing such an organic polymer is not particularly limited. For example, polyethylene carbonate (PE
C) unit (n = 2 in formula (1)), polypropylene carbonate (PPC) unit (n = 3 in formula (1)) or polyisopropylene carbonate (Pi)
The organic polymer having a PC unit (n = 3 in the formula (1)) is prepared by the method of FJ Van Natta et al. (J. Am. Chem. So.
c., 52,314 (1930)) and the method of T. Tsuruta et al. (Die Makrom
olekulare Chemie, 130, 210, (1969)). Also, by the same method,
Other organic polymers having n of 6 or less can be easily obtained.

As the organic polymer used in the solid polymer electrolyte of the present invention, one having one or more of the units of the above formula (1) can be used, and further other units can be used. It is also possible to use those having.

Further, in the polymer solid electrolyte of the present invention, the organic polymer serving as the structural material can be composed only of the organic polymer having the unit of the above formula (1). In addition to the organic polymer having the unit (1), it may be composed of a polymer blend obtained by blending another polymer compatible with the organic polymer. In this case, examples of the other polymer include PEO and the above formulas (i) to (iv).
Polymers can be mentioned. Further, the blending ratio can be appropriately determined depending on the conductivity and flexibility required for the polymer solid electrolyte film.

In the present invention, the above organic polymers are preferably crosslinked with each other. This makes it possible to prevent the organic solvent from seeping out when pressure is applied to the solid polymer electrolyte, and also to improve the mechanical strength. The crosslinking method is not particularly limited, but crosslinking can be performed by, for example, actinic radiation irradiation, light irradiation, electron beam irradiation, or heating. In this case, if necessary, trimethylsilylbenzophenone, benzoin,
Photopolymerization initiator such as 2-methylbenzoin, benzoyl peroxide, methyl ethyl ketone peroxide, polymerization initiator such as azoisobisbutyronitrile, and crosslinking agent such as toluene-2,4-diisocyanate and 4,4'-diphenylmethane diisocyanate Can be added.

On the other hand, as the metal salt contained in the polymer solid electrolyte of the present invention, those used in conventional polymer solid electrolytes can be used. For example, LiB
r, LiCl, LiI, LiSCN, LiBF ₄ , Li
AsF ₆ , LiClO ₄ , CH ₃ COOLi, CF ₃ C
OOLi, LiCF ₃ SO ₃ , LiPF ₆ , LiN (C
Lithium salts such as F ₃ SO ₂ ) ₂ and LiC (CF ₃ SO ₂ ) ₃ can be used.

As the metal salt, it is also possible to use a salt of the anion of the above-mentioned lithium salt and an alkali metal other than lithium, such as potassium or sodium. In this case, as the metal salt, a single kind may be used, or plural kinds of salts may be used at the same time.

The preferred concentration of the metal salt varies depending on the type of the metal salt, the type of organic polymer or organic solvent contained in the solid polymer electrolyte together with the metal salt, and the ratio of the metal salt to the organic solvent is low. If it is too high or too high, the conductivity will decrease, but normally it is preferable that the metal salt is contained in an amount of about 0.2 to 2 mol per 1 liter of the organic solvent, and 0.5 to 1.5 mol. Is more preferable.

As the organic solvent contained in the solid polymer electrolyte of the present invention, those which are compatible with the above-mentioned organic polymer and metal salt can be appropriately used, and an oxygen atom or a nitrogen atom is contained in the molecule. Those having at least one atom are particularly preferred. As such an organic solvent, for example,
Ethylene carbonate, propylene carbonate, dimethyl carbonate, butylene carbonate, diethyl carbonate, dimethoxyethane, tetrahydrofuran,
Examples thereof include dioxolane, γ-butyrolactone, sulfolane and dimethylformamide. These may be used alone or in combination of two or more.

The amount of the organic solvent used in the solid polymer electrolyte is not particularly limited because a high conductivity can be obtained as compared with the case where the organic solvent is not used, even if the amount is small, but the organic solvent is preferable. The amount is such that the organic polymer contained in the polymer solid electrolyte can be sufficiently swollen and does not exude from the polymer solid electrolyte. Usually, it is 50 to 9 per 100 parts by weight of the organic polymer.
It is preferably about 100 parts by weight.

The method for producing the solid polymer electrolyte of the present invention containing the above-mentioned organic polymer, metal salt and organic solvent is not particularly limited and can be obtained in various forms by various methods. For example, a polymer solid electrolyte is generally used in the form of a film, and as a film forming method for this purpose, the above-mentioned organic polymer and metal salt are dissolved in an organic solvent, and the solution is flattened. The film can be formed by a casting method in which the film is spread on a substrate and the solvent is evaporated to obtain a film. In this case, the degree of evaporation of the solvent is not until the solvent completely disappears from the solution on the substrate, but to such an extent that the solid polymer electrolyte formed on the substrate can maintain a film-like form. Evaporate so that it remains in the solid polymer electrolyte.

Alternatively, the solvent is completely evaporated from the solution on the substrate to form a solid polymer electrolyte film containing no organic solvent, and the obtained solid polymer electrolyte film is swollen by immersing it in an organic solvent. Then, excess organic solvent may be wiped off. In this case, as the organic solvent used to prepare the solution to be spread on the substrate, not only the organic solvent preferable for inclusion in the polymer solid electrolyte of the present invention as described above, but also a cast solvent having a suitable polarity. Can be widely used. Further, the amount of the organic solvent used for swelling can be controlled by the time for immersing the solid polymer electrolyte formed on the film in the organic solvent, the method of wiping off the excess organic solvent, and the like. Further, the organic solvent used for immersion may contain a metal salt, if necessary.

When the polymer solid electrolyte is formed into a film by the casting method as described above, the amount of the organic solvent used, the order of mixing the organic polymer, the metal salt and the organic solvent, etc. are prepared when the solution to be spread on the substrate is prepared. There is no particular limitation.

When the polymer solid electrolyte contains a cross-linked product as an organic polymer, in the above-mentioned casting method, the organic polymer that has already undergone a cross-linking reaction may be used, or the polymer solid electrolyte It is also possible to prepare a solution in which an uncrosslinked organic polymer, a metal salt, and an organic solvent have predetermined concentrations at the time of film formation, and the solution is subjected to a crosslinking reaction in a nitrogen atmosphere.

The polymer solid electrolyte of the present invention can be used as various electrochemical device materials including high energy density batteries such as lithium batteries.

[0044]

The organic polymer having the polyalkylene carbonate unit of the formula (1) contained in the polymer solid electrolyte of the present invention has good film-forming property even when a metal salt serving as a carrier ion is contained at a high concentration. Since the polymer solid electrolyte composed of the organic polymer having the polyalkylene carbonate unit of the formula (1) and the metal salt exhibits high conductivity because it can maintain flexibility and mechanical strength, the present invention In the above, since the solid polymer electrolyte further contains an organic solvent to swell the organic polymer, the solid polymer electrolyte exhibits extremely high conductivity.

Therefore, according to the polymer solid electrolyte of the present invention, it is possible to simultaneously realize high ionic conductivity and good film-forming property, flexibility and mechanical strength.

[0046]

EXAMPLES The present invention will be specifically described below based on examples. However, Examples 1 to 20 are non-organic polymers.
Since this is an example using a cross-linked product, in the specific example of the present invention
Not a reference example. Examples 21 to 26 are organic polymers
It is a specific example of the present invention in which a crosslinked body is used as.

Example 1 [Synthesis of polyisopropylene carbonate (PiPC)] 0.5 in a reaction vessel for an autoclave of about 200 ml.
100 ml of a benzene solution of M-Et ₂ Zn was weighed, and 1 g of 1,3-dihydroxybenzene was added thereto,
Bubbled with nitrogen gas for 3 hours. Next, 11.6 g of propylene oxide was added thereto, and this was reacted in an autoclave equipped with a stirrer under a CO ₂ atmosphere of 20 atm for 1 week. Then, a few drops of alcohol were added dropwise to terminate the reaction, and 500 ml of benzene was added thereto. Then, this solution was washed with a 1M-HCl aqueous solution, further washed with water, dried using anhydrous magnesium sulfate, concentrated, and poured into methanol with stirring.
This gave a white fibrous solid. This white solid was collected by filtration, thoroughly washed with methanol, and reprecipitated with a THF-methanol system repeatedly for 2 to 3 times for purification,
Then, the obtained solid was dried under reduced pressure. Thus, an organic polymer was obtained with a yield of 20 to 40%. This organic polymer was identified by FT-IR and ¹ H-NMR in CDCl ₃ and was confirmed to be the expected polyisopropylene carbonate. The melting point of this organic polymer is 14
0 to 150 ° C., and the average molecular weight is 1 × 10 ³ to by gel permeation chromatography (GPC).
It was 1 × 10 ⁶ .

[Preparation of Polymer Solid Electrolyte Film (Uncrosslinked Film)] The organic polymer (polyisopropylene carbonate) obtained above was added to sufficiently dehydrated THF and stirred sufficiently to form a uniform solution. Then 0.4
An insoluble matter was removed through a 5 μm filter, and a film was formed by a casting method. That is, the solution was placed in a Teflon dish having a smooth bottom surface, the solvent was evaporated in a thermostat set to a temperature range of 40 to 60 ° C. under a nitrogen atmosphere, and further vacuum heating was performed to completely remove the solvent, thereby drying. Thus, a film-shaped solid polymer electrolyte was obtained.

Next, the obtained film-like polymer solid electrolyte was immersed in a solution of propylene carbonate (hereinafter abbreviated as PC) in a concentration of 1 M of LiClO ₄ at room temperature for 3 hours to obtain a polymer solid. The electrolyte was swollen. Then, this was taken out of the solution, and the excess solution was wiped off to obtain a polymer solid electrolyte of the example.

The solid polymer electrolyte thus obtained was a highly flexible colorless to pale yellow film. The thickness of this film can be appropriately adjusted to a predetermined value according to the purpose. Here, a film having a thickness of 50 to 150 μm was manufactured in order to evaluate the conductivity as described later.

[Evaluation of Ionic Conductivity] The ionic conductivity of the obtained polymer solid electrolyte film was evaluated as follows. That is, a solid polymer electrolyte film is pressure-bonded with a platinum electrode or a lithium metal electrode, and this is heated and stored at 80 ° C. for several hours so that each electrode / film / electrode contact can be sufficiently maintained for evaluation. A cell was prepared. After that, the temperature variable thermostatic device was set to a predetermined temperature, the evaluation cell was placed therein, and the evaluation cell was allowed to stand for about 1 hour so as to be in a steady state at that temperature. Then, the constant voltage complex impedance method (AC amplitude voltage 30 to 100 mV, AC frequency band 10 ⁻² to 10 ⁷ , temperature −40 to 80).
The electrical conductivity was analytically calculated from the semi-circular arc portion obtained by (° C.). In this case, the electrodes were changed to platinum and lithium metal, and the area of the electrodes was changed so that a plurality of pseudo semi-circular arc components were assigned to the resistance portion that contributes to the ionic conductivity.

The temperature dependence of the ionic conductivity thus obtained is shown in FIG. For comparison, the ionic conductivity of the 1M-LiClO ₄ / PC solution used for swelling the organic polymer was similarly obtained, and the result is shown in FIG. 1 as a comparative example. The 1M-LiClO ₄ / PC solution has been conventionally used as a non-aqueous electrolytic solution.

From FIG. 1, it can be seen that the polymer solid electrolyte film of Example 1 has a conductivity as high as that of the non-aqueous electrolyte solution in the temperature region near room temperature, although it is a solid electrolyte.

[Evaluation of Tensile Strength] The obtained polymer solid electrolyte film was cut into strips of 10 mm × 40 mm × thickness 150 μm to prepare test pieces, and the tensile strength was measured by a general-purpose Instron tester and this. It measured using the similar tester. In this case, one of the chucks that grips the test piece is fixed to the strain gauge, and the other is electrically pulled up and down at a constant speed to continue pulling, and when the test piece breaks, the ultimate stress indicated on the strain gauge is measured as tensile strength ( kgf / cm ² ). The results are shown in Table 2.

[0055]

[Table 2] Examples 2-5 LiClO ₄ / P used to swell organic polymers
A solid polymer electrolyte membrane was prepared by repeating Example 1 except that the concentration of the C solution was changed as shown in FIG. 2, and its ionic conductivity at 25 ° C. was determined. The result is shown in FIG. In addition, in FIG. 2, the result of the electrical conductivity at 30 ° C. of Example 1 is also shown.

From FIG. 2, the conductivity becomes maximum when the salt concentration of the LiClO ₄ / PC solution is around 1 M, but 0.2 to 2.0.
It can be seen that in the range of M, the conductivity is maintained at a high value without being significantly reduced.

Examples 6 to 15 Instead of the LiClO ₄ / PC solution, as shown in FIG.
A polymer solid electrolyte membrane was prepared by repeating Example 1 except that the iBF ₄ / PC solution or LiPF ₆ / PC solution was used, and the ionic conductivity at 25 ° C. thereof was determined. The result is shown in FIG.

[0058] From FIG. 2, instead of LiClO ₄ / PC solution, also using LiBF ₄ / PC solution or LiPF ₆ / PC solution, obtained LiClO ₄ / when using PC solution as well as high conductivity You can see that

Examples 16 to 20 The polyisopropylene carbonate of Example 1 (PiP
According to the synthesis of C), the formula (1)

[0060]

[Chemical 7] In the same manner as in Example 1, each organic polymer was synthesized in the same manner as in Example 1 by synthesizing an organic polymer having a linear methylene chain in the unit of n = 2-6.
A polymer solid electrolyte film swollen with M-LiClO ₄ was prepared. Table 3 shows the relationship between the value of n in this case, the abbreviation of the corresponding organic polymer and the example number.

[0061]

[Table 3] Part 3 of each of the obtained polymer solid electrolyte films
Ionic conductivity at 0 ° C was determined in the same manner as in Example 1.
It was The result is shown in FIG. From FIG. 3, the uni
Polymer using organic polymer with straight chain methylene chain
In the case of a solid electrolyte, the conductivity when the methylene chain is n = 5
Shows a maximum, but the conductivity is large and low in the range of n = 2 to 6.
Do you know that you can achieve high values without lowering
It

The tensile strength of each polymer solid electrolyte film was determined in the same manner as in Example 1. The results are shown in Table 2.

Example 21 [Preparation of polymer solid electrolyte film (crosslinked film)] In the same manner as in Example 1, a polymer solid electrolyte film swollen with a 1M-LiClO ₄ / PC solution was obtained, which was inactive. Acceleration voltage 250kV, electron dose 8M in gas atmosphere
The organic polymer (polyisopropylene carbonate) forming the polymer solid electrolyte film was cross-linked by irradiating the electron beam of rad.

Then, the electric conductivity of the obtained polymer solid electrolyte film at a temperature of −40 to 80 ° C. was determined in the same manner as in Example 1. The result is shown in FIG.

Further, the tensile strength of the obtained polymer solid electrolyte film was determined in the same manner as in Example 1. The results are shown in Table 2.

By comparing the results of FIG. 4 and Table 2 with the corresponding results of Example 1, even if the organic polymer is crosslinked, the ionic conductivity is almost unchanged and the tensile strength is improved. Recognize. Therefore, it was confirmed that cross-linking the organic polymer could improve the mechanical strength without impairing the ionic conductivity.

Examples 22 to 26 In the same manner as in Examples 16 to 20, organic polymers having a linear methylene chain in the unit of the formula (1) and having n = 2 to 6 were synthesized. In the same manner as in Example 1
A polymer solid electrolyte film swollen with O ₄ was prepared, and the organic polymer of each polymer solid electrolyte film was crosslinked in the same manner as in Example 21.

The conductivity of the obtained polymer solid electrolyte film was determined in the same manner as in Example 1. The result is shown in FIG.

The tensile strength of the obtained polymer solid electrolyte film was determined in the same manner as in Example 1. The results are shown in Table 2.

As a result, n of the methylene chain of the organic polymer is
It is understood that the tensile strength can be improved without impairing the ionic conductivity by cross-linking the organic polymer regardless of the value of 2 to 6.

[0071]

EFFECTS OF THE INVENTION According to the present invention, it has a high ionic conductivity comparable to an electrolytic solution even at around room temperature, and has an excellent film-forming property.
It is possible to obtain a polymer solid electrolyte having flexibility and mechanical strength.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between temperature and conductivity of a polymer solid electrolyte film of an example.

FIG. 2 is a diagram showing the relationship between the type or concentration of metal salt and the conductivity of the polymer solid electrolyte film of the example.

FIG. 3 is a relationship diagram between the length of a methylene chain of an organic polymer of a polymer solid electrolyte film of an example and the conductivity.

FIG. 4 is a graph showing the relationship between the temperature and the conductivity of the polymer solid electrolyte film of the example.

FIG. 5 is a relationship diagram between the length of a methylene chain of an organic polymer and the conductivity of a polymer solid electrolyte film of an example.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-30147 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 64/00-64/42

Claims (5)

(57) [Claims] 1. The following formula (1): (Wherein n is an integer), an organic polymer having a unit, a metal salt, and an organic solvent compatible with the organic polymer and the metal salt , the organic polymer being cross-linked with each other.
A solid polymer electrolyte characterized by being present . 2. In the unit of formula (1), n = 2.
The polymer solid electrolyte according to claim 1 Symbol placement is six. 3. A solid polymer electrolyte according to claim 1 Symbol placement contained 0.2-2 mol metal salt in an organic solvent 1 liter. 4. The organic solvent is, claim 1 Symbol <br/> placing polymer solid electrolyte of an oxygen atom or a nitrogen atom consisting of those having at least one in one molecule. 5. The polymer solid electrolyte according to claim 4 , wherein the organic solvent is contained in an amount of 50 to 900 parts by weight based on 100 parts by weight of the organic polymer.