JP2008251533A - Cation conductor, intermediate, polymer electrolyte membrane, and battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep a low-temperature characteristic of an ion conductor using the rotation of a single bond, and to improve ion conductivity. <P>SOLUTION: This cation conductor is represented by a general formula (1), where R is an organic group formed by polymerizing a compound having a polymerizable unsaturated bond, (i) is the degree of polymerization of R; X is Q or S-V; Q is an organic group of a heterocyclic compound bonded to R through a single bond, and having a coordinating property to a cation, S is an organic group bonded to R, V is an organic group of a heterocyclic compound having a coordinating property to a cation, Mk+ is a k-valent cation, and (n) and (m) are integers not smaller than 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ion conductive organic electrolyte, a polymer electrolyte membrane, an intermediate thereof, and a battery such as a lithium battery using the electrolyte membrane.

  Due to advances in electronic technology, the performance of electronic devices has improved and miniaturization / portability has progressed, and a secondary battery with high energy density is desired as its power source. In response to these demands, in recent years, non-aqueous electrolyte secondary batteries that can significantly improve energy density, that is, organic electrolyte lithium ion secondary batteries (hereinafter simply referred to as “lithium batteries”) have been developed. It is rapidly spreading. Lithium batteries use, for example, lithium-containing metal composite oxides such as lithium cobalt composite oxide as the positive electrode active material, and lithium ion insertion (lithium intercalation compound formation) and interlayer as the negative electrode active material A carbon material having a multilayer structure capable of releasing lithium ions from is mainly used.

  Since lithium batteries use flammable organic electrolytes as electrolytes, it is becoming difficult to ensure safety during abuse, such as overcharge and overdischarge, as the energy density of the batteries increases. For this reason, lithium polymer batteries in which combustible organic electrolytes are replaced with solid lithium ion conductive polymers have been developed.

It is known that the ionic conduction mechanism of ion-conducting polymers studied to date occurs cooperatively with the movement of the molecular chains of the polymer. The ionic conductivity is governed by the mobility of the molecular chain, and is governed by the motion of the molecular chain having a large activation energy necessary for the segment motion. Therefore, although the ionic conductivity at room temperature is about 10 ⁻⁴ Scm ⁻¹ , it greatly decreases as the temperature decreases.

  Therefore, the present inventors have conceived of using rotation of a single bond with a low activation energy for ion conduction as an ion conduction mechanism that is not governed by the movement of molecular chains, as disclosed in Patent Document 1 so far. . And the organic group which has a functional group used as the ligand of lithium ion was couple | bonded with another organic group by the single bond, and the ion conductive polymer which can rotate freely in a wide temperature range was discovered. This ion-conductive polymer exchanges lithium ions with similar functional groups adjacent to each other by rotation, and realizes ion conduction by utilizing this exchange action. This ion conduction mechanism makes it possible to achieve a polymer electrolyte that is excellent in temperature dependency.

  Patent Document 2 relates to an ionic liquid composed of a fluoropolymer that exhibits liquid behavior in the range of room temperature to 300 ° C., and various substances are disclosed as raw materials.

  Patent Document 3 discloses a vinyl imidazoline polymer having a 5-membered ring structure as a novel polymer solid electrolyte.

JP 2004-6273 A JP 2005-350604 A JP 2000-302939 A

  An object of the present invention is to maintain the low temperature characteristics of an ionic conductor utilizing the rotation of a single bond and further improve the ionic conductivity.

  The cationic conductor according to the present invention is characterized in that it contains a substance that is solid in the range of room temperature to about 300 ° C. and has a coordination ability with respect to the cation.

  The cationic conductor according to the present invention has the following general formula (1):

(In the formula, R is an organic group in which a compound having a polymerizable unsaturated bond is polymerized, i is a polymerization degree of R, preferably 50 to 1000, X is Q or SV, and Q is a single unit with R. An organic group of a heterocyclic compound that is bonded through a bond and has a coordination ability to a cation, M ^{k +} is a k-valent cation, and n and m are integers of 1 or more. In this general formula, the heterocyclic organic group Q or V has a structure that allows easy uniaxial rotation with respect to R of the main chain, so that a cation coordinated with Q or V can coordinate with other Q or V. As a result, the ionic conductivity of the polymer is improved. Therefore, it is important that Q or V has a structure with less steric hindrance so that the uniaxial rotation is not hindered as much as possible.

  Moreover, the said general formula (1) contains the cation conductor shown by the following general formula (2).

(In the formula, R is an organic group in which a compound having a polymerizable unsaturated bond is polymerized, i is a polymerization degree of R, preferably 50 to 1000, Q is bonded to R through a single bond, An organic group of a heterocyclic compound having coordination ability, M ^{k +} is a k-valent cation, and n and m are integers of 1 or more.

  Furthermore, the general formula (1) includes a cation conductor represented by the following general formula (3).

(In the formula, R is an organic group in which a compound having a polymerizable unsaturated bond is polymerized, i is preferably a polymerization degree of R of 50 to 1000, S is an organic group bonded to R, and V is a single unit with S. A cation conductor represented by an organic group of a heterocyclic compound that is bonded via a bond and has a coordination ability to a cation, M ^{k +} is a k-valent cation, and n, m, and k are integers of 1 or more.

  This invention provides the intermediate body which is a precursor of the said cation conductor, The general formula (4) is as follows.

(In the formula, R is an organic group in which a compound having a polymerizable unsaturated bond is polymerized, X is Q or SV, Q is bonded to R via a single bond, and is capable of coordinating with a cation. An organic group of a heterocyclic compound having, M ^{k +} is a k-valent cation, and n and m are integers of 1 or more)
The general formula (4) includes an intermediate of a cation conductor represented by the following general formula (5).

(Wherein R is an organic group in which a compound having a polymerizable unsaturated bond is polymerized, Q is an organic group of a heterocyclic compound that binds to R through a single bond and has a coordination ability to a cation, M ^{k +} is a k-valent cation, n and m are integers of 1 or more)
Moreover, the said General formula (4) contains the intermediate body of the cation conductor shown by following General formula (6).

(In the formula, R is an organic group in which a compound having a polymerizable unsaturated bond is polymerized, S is an organic group bonded to R, V is bonded to S through a single bond, and is coordinated to a cation. An organic group of a heterocyclic compound having a function, M ^{k +} is a k-valent cation, and n, m, and k are integers of 1 or more)
Preferred specific examples of the cation conductor represented by the general formulas (1) to (3) include a cation conductor represented by the following general formula (7).

(Wherein R is an organic group in which a compound having a polymerizable unsaturated bond is polymerized, i is a polymerization degree of R, S is an organic group bonded to R, M ^{k +} is a k-valent cation, n, m, k is an integer of 1 or more)

  According to the present invention, while maintaining the low temperature characteristics of an ionic conductor utilizing the rotation of a single bond, an electrolyte having further improved ionic conductivity, an intermediate thereof, an electrolyte membrane, a lithium secondary battery using the electrolyte, and the like A battery can be provided.

  Embodiments of the present invention will be described in detail below.

As the cation conductor as an example according to the present invention, the cation conductor represented by the general formula (3) was used. In particular, in the cationic conductor of this example, the bond between the organic group S and the organic group V is a single bond, and V freely rotates through this single bond. In addition, the compound in this example is a cation-conducting agent because the cation M ^{k +} coordinated to the organic group Q of the heterocyclic compound having the coordination ability to the cation is easily exchanged between adjacent organic groups Q. Showing gender.

Next, a specific cationic conductor synthesis method 1 represented by the general formula (3) is shown. 4-Vinylbenzoyl chloride (19 g, 110 mmol) was added to a solution obtained by dissolving 10 g of amino-2,6-dioxane in 0.2 dm ³ of pyridine while stirring and allowed to react at room temperature for 100 hours. After adding 2% hydrochloric acid (0.2 dm ³ ) to the reaction solution, liquid separation extraction was performed using ethyl acetate. After drying over sodium sulfate and concentrating under reduced pressure, Intermediate 1 (N-2,6-dioxanyl-4-vinyl-benzamide) was obtained.

  The chemical formula of the obtained intermediate 1 of the polymer is shown below.

5 g of the obtained intermediate 1 was dissolved in 0.1 dm ³ of N-methylpyrrolidone, and 4 cm ^{3 of} N-methylpyrrolidone solution in which 0.02 g of 2,2′-azobisisobutyronitrile was dissolved was dropped. Added, stirred and heated to 100 ° C. Methanol was added dropwise to the reaction solution for reprecipitation to obtain polymer 1 (poly (N-2,6-dioxanyl-4-vinyl-benzamide)) that was solid at room temperature to 300 ° C.

  1 g of this polymer and 2 g of lithium trifluorosulfonimide salt are dissolved in 20 ml of N-methylpyrrolidone, cast on a tetrafluoroethylene sheet, dried under reduced pressure at room temperature, and cast of polymer electrolyte 1 having a thickness of 100 μm. A film was prepared. This cast film was sandwiched between stainless steel (SUS304) electrodes having a diameter of 15 mm to produce an evaluation cell.

  An AC voltage was measured by applying an amplitude voltage of 10 mV to the cell at room temperature. The frequency range was 1 Hz to 1 MHz. The ionic conductivity was determined from the reciprocal of the bulk resistance value obtained from the AC impedance measurement. The ionic conductivity was higher than that of the polymer electrolyte in the comparative example.

  The polymer of the general formula (3) will be described.

In the cation conductor of this example, the bond between the organic group S and the organic group V is a single bond, and the organic group V is freely rotated through this single bond. Moreover, the compound in a present Example shows cation conductivity by the cation ^{Mk +} coordinated to the organic group V carrying out transfer exchange easily between the adjacent organic groups V. FIG.

  Here, it is important that the bond between the organic group S and the organic group V is a single bond, but the bond between the organic group R and the organic group S is not limited to a single bond.

Next, a specific cationic conductor synthesis method 2 represented by the general formula (3) is shown. To a solution obtained by dissolving 12.5 g of 2-amino-s-triazine in 0.2 dm ³ of pyridine, 19 g of 4-vinylbenzoyl chloride was added with stirring and reacted at room temperature for 100 hours. After adding 2% hydrochloric acid 0.2 dm ³ to the reaction solution, liquid separation extraction was performed using ethyl acetate. After drying over sodium sulfate, the reaction mixture was concentrated under reduced pressure to obtain Intermediate 2 (Ns-triazinyl-4-vinylbenzamide) that appeared to be a solid.

  The chemical formula of the obtained intermediate 2 is shown below.

5 g of the obtained intermediate 2 was dissolved in 0.1 dm ³ of N-methylpyrrolidone, and 4 cm ³ of an N-methylpyrrolidone solution in which 0.02 g of 2,2′-azobisisobutyronitrile was dissolved was dropped. Added, stirred and heated to 100 ° C. Methanol was added dropwise to the reaction solution for reprecipitation to obtain polymer 2 (poly (Ns-triazinyl-4-vinylbenzamide)) that was solid at room temperature to 300 ° C.

  1 g of this polymer and 2.5 g of lithium trifluorosulfonimide salt are dissolved in 20 ml of N-methylpyrrolidone, cast on a tetrafluoroethylene sheet, dried under reduced pressure at room temperature, and a polymer electrolyte having a thickness of 100 μm. A cast film membrane according to 2 was produced. This cast film was sandwiched between stainless steel (SUS304) electrodes having a diameter of 15 mm to produce an evaluation cell.

  An AC voltage was measured by applying an amplitude voltage of 10 mV to the cell at room temperature. The frequency range was 1 Hz to 1 MHz. The ionic conductivity was determined from the reciprocal of the bulk resistance value obtained from the AC impedance measurement. The ionic conductivity was higher than that of the polymer electrolyte in the comparative example.

  The polymer of the general formula (3) will be described.

  In this example, the organic group R is polystyrene, but the organic group R is not particularly limited, and various organic groups such as saturated hydrocarbon compounds, unsaturated hydrocarbon compounds, and aromatic hydrocarbon compounds can be applied. It is. It is not limited to the organic group of the hydrocarbon compound and may contain elements such as nitrogen, sulfur and oxygen. The molecular weight is not limited, and low molecular weight compounds to high molecular weight compounds can be used. The high molecular weight compound may be a polymer of a low molecular weight compound monomer.

  When R is a polymer compound, it may be a number corresponding to the degree of polymerization of the monomer. In addition, a plurality of each monomer may be substituted. There is no restriction | limiting about the means of superposition | polymerization, Addition polymerization, polyaddition, polycondensation, etc. can be used.

  The organic group V in this example is a heterocyclic compound having one or more elements capable of coordinating cations. In particular, the organic group V is preferably a heterocyclic aromatic compound such as a pyridyl group, a pyrimidyl group, or an s-triazinyl group.

In the cation conductor described in Patent Document 1, a functional group having a lithium ion coordination property, for example, a methoxy group (—OCH ₃ ) is introduced as a substituent for an aromatic compound having a six-membered ring structure. It has a structure in which a dimethoxyphenyl group is bonded to the polymer main chain via an amide group. Ionic conduction occurs by moving through a single bond connecting the dimethoxyphenyl group and the amide group.

  During this movement, it is considered that the methoxy group having lithium ion coordinating properties introduced as a substituent acts inhibitory to the movement that conducts ions depending on the molecular size of the functional group itself. It is done. In addition, the substituent having lithium ion coordinating properties not only inhibits the rotation of a single bond, but also affects the solubility of the cation conductor in an organic solvent, thereby impairing workability.

  In the cation conductor according to the present invention, the organic group V is a heterocyclic aromatic compound having a six-membered ring structure but containing atoms other than carbon atoms and hydrogen atoms. In that case, when the atom to contain exists in a 6-membered ring structure, ion coordination property is shown.

  In the structure for achieving movement through a single bond for conducting ionic conduction, the function for coordination of ions is not a substituent which is a functional group having ion coordination, but ion coordination. This can be achieved only with a 6-membered ring structure composed of the elements shown. For this reason, the above-mentioned problem can be solved without hindering the rotational movement for ion conduction.

Next, a specific cationic conductor synthesis method 3 represented by the general formula (3) is shown. 13.3 g of 2-hydroxypyrimidine hydrochloride was dissolved in 0.2 dm ³ of tetrahydrofuran, and 12.1 g of triethylamine was added. While stirring, 15.5 g of methacrylic acid-2-isocyanate ethyl ester was added to the solution and reacted at 60 ° C. for 30 hours. The reaction solution was concentrated under reduced pressure, 2% hydrochloric acid 0.2 dm ³ was added, and liquid separation extraction was performed using ethyl acetate. After drying with sodium sulfate, the reaction mixture was concentrated under reduced pressure to obtain Intermediate 3 that appeared to be a solid.

  The chemical formula of the obtained intermediate 3 is shown below.

5 g of the obtained intermediate ³ was dissolved in 0.1 dm ³ of N-methylpyrrolidone, and 4 cm ³ of an N-methylpyrrolidone solution in which 0.02 g of 2,2′-azobisisobutyronitrile was dissolved was dropped. Added, stirred and heated to 100 ° C. Methanol was added dropwise to the reaction solution for reprecipitation to obtain polymer 3 that was solid at room temperature to 300 ° C.

  1 g of this polymer and 2.3 g of lithium trifluorosulfonimide salt are dissolved in 20 ml of N-methylpyrrolidone, cast onto a tetrafluoroethylene sheet, dried under reduced pressure at room temperature, and a polymer electrolyte having a thickness of 100 μm. A cast film membrane according to 3 was prepared. This cast film is sandwiched between stainless steel (SUS304) electrodes having a diameter of 15 mm to produce an evaluation cell.

  An AC voltage was measured by applying an amplitude voltage of 10 mV to the cell at room temperature. The frequency range was 1 Hz to 1 MHz. The ionic conductivity was determined from the reciprocal of the bulk resistance value obtained from the AC impedance measurement. The ionic conductivity was higher than that of the polymer electrolyte in the comparative example.

  Further, in the cation conductor according to an embodiment of the present invention, S in the general formula (3) is an amide group, C (carbon atom) is bonded to R, and N (nitrogen atom) of the amide group is bonded to the cation conductor. It is a compound represented by the general formula (8) having an amide group to which a pyrimidyl group is bonded. Such compounds are most preferred.

  In such a compound, a structure when a cation is coordinated to each of two nitrogen atoms which are ion-coordinating properties of a pyrimidyl group will be described. The presence of an amide group in the vicinity of the pyrimidyl group having a nitrogen atom capable of coordinating to the cation in the 6-membered ring structure, thereby allowing the oxygen atom of the carbonyl group (—C═O) in the amide group and the nitrogen of the pyrimidyl group. It becomes possible to coordinate to a cation by two ion-coordinating functional groups with an atom. In the other of the two nitrogen atoms in the 6-membered ring structure of the pyrimidyl group, the functional group to which the cation can coordinate is only the nitrogen atom in the 6-membered ring structure of the pyrimidyl group. Thus, when the cation is coordinated to two nitrogen atoms of the pyrimidyl group, one side is two coordinations with the nitrogen atom of the pyrimidyl group and the oxygen atom of the carbonyl group, and the other is the nitrogen atom of the pyrimidyl group. Coordination ability will be different, such as only coordination.

  In such a state where a large number of structures having functional groups having different coordinating abilities existing in the same molecule are arranged, the movement of the cation is promoted. Thereby, the movement of the cation from the functional group having a low cation coordination ability to the functional group having a high coordination ability is promoted. When such a mechanism is used, that is, when the rotational motion of a single bond having a low activation energy is used for ionic conduction, for example, high ionic conductivity can be obtained even at a low temperature at which the segment motion of the polymer is suppressed. Furthermore, when the organic group S such as an amide group is included, a higher ionic conductivity can be obtained by expressing the difference in the coordination ability of the cation.

Next, a specific cationic conductor synthesis method 3 represented by the general formula (8) is shown. To a solution obtained by dissolving 12 g of 2-aminopyrimidine in 0.2 dm ³ of pyridine, 19 g of 4-vinylbenzoyl chloride was added with stirring and reacted at room temperature for 97 hours. After adding 2% hydrochloric acid 0.2 dm ³ to the reaction solution, liquid separation extraction was performed using ethyl acetate. After drying over sodium sulfate, the mixture was concentrated under reduced pressure to obtain solid intermediate 4 (N-pyrimidinyl-4-vinylbenzamide).

  The chemical formula of the obtained intermediate 4 is shown below.

5 g of the obtained intermediate 4 was dissolved in 0.1 dm ³ of N-methylpyrrolidone, and 4 cm ³ of an N-methylpyrrolidone solution in which 0.05 g of 2,2′-azobisisobutyronitrile was dissolved was dropped. Added, stirred and heated to 100 ° C. Methanol was added dropwise to the reaction solution for reprecipitation to obtain polymer 4 (poly (N-pyrimidinyl-4-vinylbenzamide)) that was solid at room temperature to 300 ° C. The overall synthesis reaction is as follows.

  1 g of this polymer and 2.5 g of lithium trifluorosulfonimide salt are dissolved in 20 ml of N-methylpyrrolidone, cast onto a tetrafluoroethylene sheet, dried under reduced pressure at room temperature, and polymer electrolyte 4 having a film thickness of 100 μm. A cast film membrane was prepared. This cast film was sandwiched between stainless steel (SUS304) electrodes having a diameter of 15 mm to produce an evaluation cell.

  An AC voltage is measured by applying an amplitude voltage of 10 mV to the cell at room temperature. The frequency range was 1 Hz to 1 MHz. The ionic conductivity was determined from the reciprocal of the bulk resistance value obtained from the AC impedance measurement. The ionic conductivity was higher than that of the polymer electrolyte in the comparative example.

  The polymer of the following general formula (9) will be described.

14.3 g of 2-pyrimidinecarboxyl chloride is dissolved in 0.3 dm ³ of distilled and dried tetrahydrofuran, and 12.0 g of 4-aminostyrene is slowly added dropwise and stirred at room temperature for 2 days. The reaction solution is concentrated, and the ethyl acetate layer is extracted from ethyl acetate and 2N hydrochloric acid. This was washed with hydrochloric acid and saturated brine, dried over sodium sulfate, concentrated and purified to obtain Intermediate 5 (N- (4-vinylphenyl) pyrimidine-2-carboxylic amide) which appeared to be a solid.

  The chemical formula of the obtained intermediate 5 is shown below.

5 g of the obtained intermediate 5 was dissolved in 0.1 dm ³ of N-methylpyrrolidone, and 4 cm ³ of an N-methylpyrrolidone solution in which 0.05 g of 2,2′-azobisisobutyronitrile was dissolved was dropped. Added, stirred and heated to 100 ° C. Methanol was added dropwise to the reaction solution for reprecipitation to obtain polymer 5 (poly (N- (4-vinylphenyl) pyrimidine-2-carboxylic amide)) that was solid at room temperature to 300 ° C.

  To 1 g of this polymer, a predetermined amount of lithium trifluorosulfonimide salt was added to each side chain while changing the number of equivalents, dissolved in 20 ml of N-methylpyrrolidone, cast on a tetrafluoroethylene sheet, The film was dried under reduced pressure at room temperature to produce a cast film of polymer electrolyte 5 having a film thickness of 100 μm. This cast film was sandwiched between stainless steel (SUS304) electrodes having a diameter of 15 mm to produce an evaluation cell.

  An AC voltage was measured by applying an amplitude voltage of 10 mV to the cell at room temperature. The frequency range was 1 Hz to 1 MHz. The ionic conductivity is obtained from the reciprocal of the bulk resistance value obtained from the AC impedance measurement. The ionic conductivity was higher than that of the polymer electrolyte in the comparative example. The measurement results are shown in FIG.

  In this figure, the horizontal axis represents the addition equivalent of lithium salt, and the vertical axis represents ionic conductivity. Below the graph, structural formulas of Example 5 and the conventional example of the present invention are shown. In the case of Example 5 of the present invention, the measurement result is shown by changing the addition equivalent of the lithium salt from 0.5 equivalent to 5 equivalent. On the other hand, in the case of a conventional example, it is the result of measuring the addition equivalent of lithium salt as 1 equivalent and 2 equivalents.

  In Example 5 of the present invention, the ionic conductivity is maximized at 2 equivalents. From this figure, in the case of Example 5, it turns out that ion conductivity is high in the range whose addition equivalent of lithium ion is 0.5-5 equivalent compared with the prior art example. And the addition equivalent of a desirable lithium ion is 1-2 equivalent.

  When cations are coordinated to the two nitrogen atoms of the pyrimidyl group, one is coordinated with the nitrogen atom of the pyrimidyl group and the oxygen atom of the carbonyl group, and the other is coordinated with only the nitrogen atom of the pyrimidyl group. It is possible to form different coordination states such as positions.

  Therefore, two ionic coordinations between the oxygen atom of the carbonyl group (—C═O) in the amide group and the nitrogen atom of the pyrimidyl group due to different bonding directions of the amide group that bonds the functional group R and the pyrimidyl group. The coordination distance of the functional functional group to the cation changes. For this reason, the bonding direction of the amide group that bonds the functional group R and the pyrimidyl group controls the difference in the coordination ability to the cation.

  Since the movement of the cation is promoted in a state where a large number of structures having functional groups having different coordinating ability in the same molecule are arranged, the bonding direction of the amide group is also effective. Therefore, the movement of a cation from a functional group having a low cation coordination ability to a functional group having a high coordination ability is affected.

  The functional group to which lithium ions coordinate in the conventional material shown in the comparative example is an oxygen atom of the methoxy group, whereas the functional group to which lithium ions coordinate in the present invention is a pyrimidyl that forms a side chain. Since it is a nitrogen atom of the group, it is thought that the coordination mode of ions is different.

  In this embodiment, lithium is used as the cation to be used, but it is also possible to use alkali metal ions such as sodium and potassium, alkaline earth metals such as magnesium, or hydrogen ions. Of these, lithium ions are most preferred.

A lithium salt can be used as a supply source of lithium ions. As the lithium salt, one or more of LiN (CF ₃ SO ₂ ) ₂ , LiN (CF ₃ CF ₂ SO ₂ ) ₂ , LiClO ₄ , LiPF ₆ , LiBF ₄ , and LiAsF ₆ are selected and used. be able to. About the addition amount of lithium ion, 1 equivalent or more is preferable by molar ratio with respect to one organic group V in connection with lithium conduction.

  FIG. 3 is a graph comparing Example 5 according to the present invention with data described in Patent Document 3.

  In this figure, the horizontal axis represents temperature and the vertical axis represents ion conductivity. The case where the addition equivalent of the lithium salt of Example 5 is 1 equivalent and 2 equivalent is shown.

  From comparison between Example 5 according to the present invention and the data described in Patent Document 3, it can be seen that the ion conductivity of Example 5 according to the present invention is higher at a normal use temperature of 40 ° C. or lower.

  The solid polymer electrolyte described in Patent Document 3 is a mixture of a vinyl imidazoline polymer, a metal salt, and a plasticizer. On the other hand, the polymer solid electrolyte according to the present invention does not use an additive such as a plasticizer. In this respect, it is considered that the solid polymer electrolyte according to the present invention can be more easily produced.

  FIG. 1 is a cross-sectional view of a lithium battery using a cation conductive polymer electrolyte as one embodiment of the present invention.

  The lithium ion conductive polymer electrolyte 3 of this example is composed of a composite of a polymer and a lithium salt, and an intermediate of a cation conductor having an organic group contributing to ionic conduction and a lithium salt are organically mixed. It can be obtained by polymerizing a solution dissolved in a solvent and then removing the organic solvent.

  When the polymer electrolyte 3 is used as an electrolyte for a lithium battery and also serves as a separator between the positive electrode 1 and the negative electrode 2, it is formed into a sheet shape. In order to obtain this sheet-like polymer electrolyte 3, polymerization is performed by addition polymerization by heating a solution in which an intermediate of a cation conductor having an organic group contributing to ionic conduction and a lithium salt is dissolved in an organic solvent, It can be obtained by a method of evaporating off the organic solvent. Moreover, after adding a lithium salt to what mixed the solution which melt | dissolved the cation conductor in the organic solvent, after casting on a polytetrafluoroethylene sheet | seat, it can also obtain by the method of evaporating and removing an organic solvent.

  Examples of the organic solvent for dissolving the polymer electrolyte 3 and the lithium salt include substances that sufficiently dissolve the lithium salt and do not react with the polymer electrolyte 3, such as N-methylpyrrolidone, dimethylformamide, toluene, propylene carbonate, and γ-butyrolactone. Used.

Further, as a positive electrode active material that reversibly occludes / releases lithium, a layered compound such as lithium cobaltate (LiCoO ₂ ), lithium nickelate (LiNiO ₂ ), or one substituted with one or more transition metals, manganic acid Lithium (Li _{1 + x} Mn _2-x O ₄ (where x = 0 to 0.33), Li _{1 + x} Mn _2-xy M _y O ₄ (where M is Ni, Co, Cr, Cu, Fe, Al, Including at least one metal selected from Mg, x = 0 to 0.33, y = 0 to 1.0, ₂ -xy> 0), LiMnO ₃ , LiMn ₂ O ₃ , LiMnO ₂ , LiMn _2-x M _x O ₂ (where M includes at least one metal selected from Co, Ni, Fe, Cr, Zn, and Ta, x = 0.01 to 0.1), Li ₂ Mn ₃ MO ₈ (was And, M includes Fe, Co, Ni, Cu, at least one metal selected from Zn), copper - lithium oxide _{(Li 2 CuO 2), LiV} 3 O 8, LiFe 3 O 4, V 2 Mixtures containing vanadium oxides such as O ₅ , V ₆ O ₁₂ , VSe, Cu ₂ V ₂ O ₇ , disulfide compounds, Fe ₂ (MoO ₄ ) ₃ , or one or two of polyaniline, polypyrrole, polythiophene, etc. The above is mentioned.

  Examples of the negative electrode active material that reversibly occludes and releases lithium include graphitized materials obtained from natural graphite, petroleum coke, coal pitch coke, etc., heat-treated at a high temperature of 2500 ° C. or higher, mesophase carbon, amorphous Carbonaceous carbon, carbon fiber, lithium metal, metal alloying with lithium, or a material having a metal supported on the surface of carbon particles is used. For example, a metal selected from lithium, aluminum, tin, silicon, indium, gallium, and magnesium, or an alloy thereof. Further, the metal or the oxide of the metal can be used as a negative electrode active material.

  The polymer battery of this example can be obtained by sandwiching a sheet-shaped polymer electrolyte 3 between a positive electrode 1 prepared using the positive electrode active material and a negative electrode 2 prepared using the negative electrode active material. In addition, in order to improve the adhesion between the positive electrode active material and the polymer electrolyte 3 or the adhesion between the negative electrode active material and the polymer electrolyte 3, it is possible to produce the positive electrode 1 and the negative electrode 2 including the polymer electrolyte 3. It is.

  Further, the polymer battery of this example can also be produced by winding or laminating the positive electrode 1 and the negative electrode 2 with the polymer electrolyte 3 interposed therebetween.

  In this case, polymerization is performed by heating and adding a solution in which an intermediate of a cation conductor having an organic group contributing to ionic conduction and a lithium salt is dissolved in an organic solvent on the positive electrode 1 and the negative electrode 2 by heating. And the organic solvent is removed by evaporation. Alternatively, a solution obtained by mixing a solution obtained by dissolving a cation conductor in an organic solvent and adding a lithium salt is cast on an electrode to remove the organic solvent. It is also possible to obtain a polymer battery by bonding the positive electrode 1 and the negative electrode 2 thus obtained.

  Moreover, it is suitable for mounting on the electrical equipment as shown below. For example, electric car, electric bicycle, personal computer, mobile phone, digital camera, video recorder, mini-disc portable player, digital audio player, personal digital assistant, wristwatch, radio, electronic notebook, electric tool, vacuum cleaner, toy, elevator, It can be used as an electrolyte for lithium secondary batteries as power sources for disaster robots, walking aids for medical care, wheelchairs for medical care, mobile beds for medical care, emergency power supplies, road conditioners, power storage systems, etc. ( Example 6).

  In addition, since no electrolyte is used, the safety is expected to increase and the protection circuit is expected to be unnecessary, so that it can be used as a rechargeable battery for home use, and can be enlarged. Suitable for distributed power supply for home and community. In addition, since the performance at room temperature is maintained even at low temperatures and liquid leakage does not occur at high temperatures, it can be used in a wide range of temperature conditions in addition to these consumer applications. Also suitable for applications.

  In addition, a laminated battery in which the battery is sealed with an aluminum laminated film 4 can be used. In this case, since it can be reduced in thickness and size, it is suitable for use in electronic paper and sensor networks.

It is also conceivable that M ^{k +} in the general formulas (1) to (3) is used as an electrolyte membrane of a fuel cell by using hydrogen ions.
(Comparative example)
A method for synthesizing a cation conductor using a homopolymer composed of a comparative example intermediate (intermediate 1 described in Patent Document 1) obtained by the method described in Patent Document 1 is shown. The structure of the intermediate is as shown below.

140 g of the comparative example intermediate of the obtained cation conductor was dissolved in 5 dm ³ of tetrahydrofuran, 0.4 g of azobisisobutyronitrile was added thereto, and the mixture was stirred at 65 ° C. This reaction solution was added dropwise to 10 dm ³ of n-hexane to obtain a comparative polymer (poly (N- (4-vinylphenyl) -2,6-dimethoxy-benzoic acid amide)). The structure of the obtained polymer is as follows.

50 g of the obtained polymer was dissolved in 2 dm ³ of N-methylpyrrolidone, a predetermined amount of lithium trifluorosulfonimide salt was added and mixed so as to be 1 equivalent and 2 equivalents with respect to the side chain, and then Teflon (registered) The film was cast on a sheet and dried under reduced pressure at 60 ° C. to prepare a cast film of a comparative polymer electrolyte film having a thickness of 100 μm. Using this cast film, the ionic conductivity was determined in the same manner as in Example 1.

  As can be understood from the structures of the comparative intermediate and the comparative polymer, CO and O are relatively close to each other in the vicinity of the 6-membered ring bonded to the main chain, so that the rotation of the 6-membered ring is inhibited. it is conceivable that. On the other hand, since the polymer of the present invention is devised so as to have as little steric hindrance as possible, the ionic conductivity is increased.

It is sectional drawing which shows the structure of the lithium secondary battery of the Example by this invention. It is a graph which shows the effect of Example 5 by this invention. It is the graph which compared Example 5 and the data of patent document 3 by this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Positive electrode, 2 ... Negative electrode, 3 ... Polymer electrolyte, 4 ... Aluminum laminated film.

Claims (24)

The following general formula (1)

(Wherein R is an organic group in which a compound having a polymerizable unsaturated bond is polymerized, i is a polymerization degree of R, X is Q or SV, Q is bonded to R through a single bond, An organic group of a heterocyclic compound having a coordinating ability to a cation, S is an organic group that binds to the R, and V is a complex having a coordinating ability to the cation by binding to the S through a single bond. An organic group of a cyclic compound, M ^{k +} is a k-valent cation, and n and m are integers of 1 or more). The following general formula (2)

(In the formula, R is an organic group in which a compound having a polymerizable unsaturated bond is polymerized, i is a polymerization degree of R, Q is bonded to R through a single bond and has a coordination ability to a cation. The cation conductor according to claim 1, which is represented by an organic group of a cyclic compound, M ^{k +} is a k-valent cation, and n and m are integers of 1 or more. The following general formula (3)

(In the formula, R is an organic group in which a compound having a polymerizable unsaturated bond is polymerized, i is a polymerization degree of R, S is an organic group bonded to R, and V is bonded to S through a single bond. The cation conductor according to claim 1, which is represented by: an organic group of a heterocyclic compound having coordination ability with respect to a cation, M ^{k +} is a k-valent cation, and n, m, and k are integers of 1 or more.   The cationic conductor according to claim 1, wherein R in the general formulas (1), (2) and (3) is an organic group having a polymerizable functional group. .   The cation according to any one of claims 1 to 3, wherein R in the general formulas (1), (2) and (3) is an organic group having an unsaturated bond capable of addition polymerization. Conductor.   The cation conductor according to claim 3, wherein the V in the general formula (3) has a heterocyclic aromatic compound having a six-membered ring structure containing nitrogen having an ionic coordination property.   The cation conductor according to claim 2, wherein the Q in the general formula (2) is an organic group of a heterocyclic aromatic compound having a six-membered ring structure.   The cation conductor according to claim 3, wherein the S in the general formula (3) is an amide group.   The cation conductor according to claim 3 or 6, wherein the V in the general formula (3) is a pyridyl group.   The cationic conductor according to claim 3 or 6, wherein the V in the general formula (3) is a pyrimidyl group. The cation conductor according to claim 1, wherein the cation M ^{k +} in the general formula (2) or (3) is a lithium ion.   The cationic conductor according to claim 11, wherein an addition equivalent of the lithium ion is 0.5 to 5 equivalents.   The cationic conductor according to claim 11, wherein an addition equivalent of the lithium ion is 1 to 2 equivalents.   The cationic conductor according to claim 6, wherein the position of nitrogen having an ionic coordination property in the heterocyclic compound in V is an amide group of the heterocyclic compound having a six-membered ring structure contained in V A cationic conductor, characterized in that it is in an ortho position that is adjacent to the bonding position.   The cation conductor according to claim 7, wherein the position of nitrogen having an ion coordination property in the heterocyclic compound in the general formula (2) is a six-membered ring structure included in the Q A cationic conductor, wherein the compound is located in an ortho position adjacent to the bonding position of the compound to R. The cation conductor according to claim 14 or 15, wherein the cation M ^{k +} in the general formula (2) or (3) is a lithium ion.   The cation conductor according to claim 16, wherein an addition equivalent of the lithium ion is 0.5 to 5 equivalent.   The cation conductor according to claim 16, wherein an addition equivalent of the lithium ions is 1 to 2 equivalents. The following general formula (4)

(Wherein R is an organic group having a polymerizable functional group, X is Q or SV, Q is bonded to R via a single bond and has a coordination ability to a cation. An intermediate of a cation conductor represented by an organic group of the compound, M ^{k +} is a k-valent cation, and n and m are integers of 1 or more. The following general formula (5)

(In the formula, R is an organic group having a polymerizable functional group, Q is bonded to R through a single bond, and is an organic group of a heterocyclic compound having a coordination ability to a cation, and M ^{k +} is a k valence. The cation conductor intermediate according to claim 19, wherein n and m are each an integer of 1 or more. The following general formula (6)

(Wherein R is an organic group having a polymerizable unsaturated bond, S is an organic group bonded to R, and V is a complex having a coordination ability to a cation by binding to S through a single bond. The intermediate of a cation conductor according to claim 19, which is represented by an organic group of a cyclic compound, M ^{k +} is a k-valent cation, and n, m, and k are integers of 1 or more.   The cation conductor containing the copolymer of the intermediate body of the cation conductor in any one of Claims 19-21, and a polymeric compound.   A polymer electrolyte membrane comprising the cation conductor according to claim 1 formed thereon.   A positive electrode having a positive electrode active material capable of occluding and releasing cations and a negative electrode having a negative electrode active material capable of occluding and releasing cations, wherein the positive electrode and the negative electrode are wound via a polymer electrolyte membrane or The battery according to claim 23, wherein the polymer electrolyte film is a polymer electrolyte film according to claim 23.

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