JPWO2007086518A1 - Electrolyte composition for secondary battery, electrolyte film, and secondary battery - Google Patents

Abstract

An electrolyte composition for a secondary battery comprising an organic compound represented by the formula: M (OR1) (OR2) (OR3), an ion conductive polymer, and an electrolyte salt compound. Wherein M is a group 3B element of the periodic table; one or two of R1, R2 and R3 is-(CH2CH2O) nR4, and the other two or one is -Si (R5) (R6) (R7). To express. R4 is alkyl, alkenyl, phenyl or alkylphenyl; R5, R6 and R7 are alkyl, alkenyl, phenyl or alkylphenyl, alkyloxy, alkenyloxy, phenyloxy, alkylphenyloxy, fluoroalkyl, acryloxyalkyl, methacryloxyalkyl or Nitrogen-containing alkylene, n is an integer of 1-50. A secondary battery having an electrolyte film formed by molding the electrolyte composition stably exhibits a high capacity.

Description

  The present invention relates to an electrolyte composition for a secondary battery that gives a molded article having a high ion conductivity and a high transport number, an electrolyte film comprising the composition, and a secondary battery containing the electrolyte film.

  Secondary batteries typified by lithium batteries are indispensable as power sources for small electric devices such as mobile phones and notebook personal computers. In recent years, secondary batteries using solid polymer electrolytes have been developed in order to overcome the drawbacks of secondary batteries such as leakage of electrolyte solution and evaporation. In particular, a film made of a polyether-based polymer such as an ethylene oxide-propylene oxide copolymer is soluble in an electrolyte salt compound such as a lithium salt compound. Therefore, as a solid electrolyte having ion conductivity for a secondary battery. Expected. However, the ionic conductivity of this electrolyte film is still insufficient. Moreover, since the adhesiveness with the positive electrode film and negative electrode film which are each laminated | stacked on the front and back of an electrolyte film is lacking, there exists a problem that the battery characteristic is inferior, such as low initial capacity.

In response to these problems, Patent Document 1 discloses that a monomer is polymerized after mixing a borate ester compound having an alkylene oxide repeating unit, an ionic compound, and an acrylate monomer having ethylene glycol in the side chain. The electrolyte film obtained by the above was proposed. However, this film still has insufficient adhesion to the positive electrode film and the negative electrode film, and the battery using this film has a large initial capacity fluctuation and the film thickness is as thick as 0.5 mm, so the smoothness of the film is lowered. However, it is electrochemically inhomogeneous and has a problem of low battery output.

In Patent Document 2, an alkylene oxide repeating unit-containing boron compound having a (meth) acryloyl group is poured into a fluororesin boat in the presence of a radical polymerization initiator and an electrolyte salt compound to polymerize the electrolyte film with high ion conductivity. Reported to get. However, this film cannot be said to have improved battery output for the same reason as described above.
Patent Document 3 discloses a crosslinkable group-containing monomer, a mixture of a polyether having a boron atom in the molecular structure, and an electrolyte salt compound spread on a stainless steel foil and irradiated with an electron beam. A solid polymer electrolyte has been disclosed. However, even if this film is used, the problem of the battery output due to the decrease in the smoothness of the film is exactly the same as the above two and is still unsolved.
Moreover, as for the electrolyte film described in said three patent documents, all have the adhesiveness at the time of lamination | stacking with a positive electrode film or a negative electrode film.

Japanese Patent Laid-Open No. 2001-155571 JP 2004-182982 A JP 2003-92138 A

  An object of the present invention is to stably provide an electrolyte composition for a secondary battery that gives a film having high ionic conductivity and transport number and excellent interlayer adhesion; an electrolyte film comprising the composition; and the electrolyte film. The object is to provide a secondary battery exhibiting a high capacity.

  As a result of intensive studies to achieve the above object, the present inventors have made an electrolyte film comprising an electrolyte composition containing an organic compound having a specific chemical structure, and the film and preferably a positive electrode film containing the composition Based on this finding, the present inventors have completed the present invention.

Thus, according to the present invention, there are provided secondary battery electrolyte compositions, electrolyte films, positive electrode forming compositions, positive electrode films, and secondary batteries listed in the following 1-21.
1. An electrolyte composition for a secondary battery comprising an organic compound represented by the following general formula (1), an ion conductive polymer and an electrolyte salt compound.
M (OR ¹ ) (OR ² ) (OR ³ ) (1)
Where M is a periodic table group 3B element;
One or two of R ¹ , R ² and R ³ is — (CH ₂ CH ₂ O) _n R ⁴ , and the other two or one is —Si (R ⁵ ) (R ⁶ ) (R ⁷ ). Represents.
R ⁴ represents an alkyl group, an alkenyl group, a phenyl group or an alkylphenyl group;
R ⁵ , R ⁶ and R ⁷ are alkyl group, alkenyl group, phenyl group or alkylphenyl group, alkyloxy group, alkenyloxy group, phenyloxy group, alkylphenyloxy group, fluoroalkyl group, acryloxyalkyl group, methacryloxy An alkyl group or a nitrogen-containing alkylene group;
n is an integer of 1-50.

2. The content of the organic compound and the electrolyte salt compound represented by the general formula (1) is 10 to 400 parts by weight and 5 to 70 parts by weight, respectively, per 100 parts by weight of the ion conductive polymer. An electrolyte composition for a secondary battery.
3. 3. The secondary battery electrolyte composition according to 1 or 2 above, wherein M in the general formula (1) is boron or aluminum.
4). The organic compound represented by the general formula (1) converts all —OH groups in the compound represented by the formula M (OR ⁸ ) (OR ⁹ ) OH to —OSi (R ⁵ ) (R ⁶ ) (R ⁷ ). 4. The electrolyte composition for a secondary battery according to any one of 1 to 3 above, wherein
Here, R ⁸ represents (CH ₂ CH ₂ O) _n R ⁴ , and R ⁹ represents H or (CH ₂ CH ₂ O) _n R ⁴ .

5. 5. The electrolyte composition for a secondary battery according to any one of 1 to 4 above, wherein the ion conductive polymer is an organic polymer having an alkylene oxide structure or a carbonate structure in the main chain or side chain.
6). 1 to 5 above, wherein the ion conductive polymer is a polymer having 50 to 100 mol% of ethylene oxide repeating units and 50 to 0 mol% of repeating units of other oxirane monomers copolymerizable with ethylene oxide. The electrolyte composition for secondary batteries in any one of.

7). Other oxirane monomers copolymerizable with ethylene oxide are alkylene oxides having 3 to 20 carbon atoms, glycidyl ethers having 4 to 10 carbon atoms, oxides of aromatic vinyl compounds, and crosslinking to these oxirane monomers. 7. The electrolyte composition for a secondary battery as described in 6 above, which is at least one selected from crosslinkable oxirane monomers into which a functional group is introduced.
8). 8. The electrolyte composition for a secondary battery according to any one of 1 to 7 above, wherein the weight average molecular weight (Mw) of the ion conductive polymer is in the range of 5,000 to 5,000,000.

9. Furthermore, the electrolyte composition for secondary batteries in any one of said 1-8 formed by containing 3-50 weight part of fumed silica with respect to 100 weight part of ion conductive polymers.
10. Furthermore, the triester compound in which R ¹ , R ² and R ³ in the general formula (1) are — (CH ₂ CH ₂ O) _n R ⁴ is added in an amount of 2 to 80 with respect to 100 parts by weight of the ion conductive polymer. The electrolyte composition for secondary batteries according to any one of 1 to 9 above, which is contained by weight.

11. Furthermore, the following general formula ^{_{R 4 (OCH 2 CH 2)}} n -Si (R 5) (R 6) (R 7)
The electrolyte composition for secondary batteries in any one of said 1-10 formed by containing 5-100 weight part of compounds represented by these with respect to 100 weight part of ion conductive polymers.
12 Furthermore, the electrolyte composition for secondary batteries in any one of said 1-11 formed by containing 0.1-10 weight part of crosslinking agents with respect to 100 weight part of said ion conductive polymers.

13. The electrolyte film formed by shape | molding the electrolyte composition for secondary batteries in any one of said 1-12, or shape | molding and bridge | crosslinking.
14 The composition for positive electrode formation containing the electrolyte composition for secondary batteries in any one of said 1-12, a positive electrode active material, and an electroconductivity imparting agent.
15. 15. The composition for forming a positive electrode according to 14 above, wherein the conductivity imparting agent is carbon particles having an average particle diameter of 10 to 80 nm.

16. 16. The composition for forming a positive electrode according to 14 or 15 above, wherein the amount of the conductivity imparting agent is 1 to 30 parts by weight with respect to 100 parts by weight of the positive electrode active material.
17. The ratio between the amount of the positive electrode active material and the amount of the organic compound represented by the general formula (1) in the secondary battery electrolyte composition is such that the amount of the organic compound is 100 parts by weight of the positive electrode active material. The composition for positive electrode formation in any one of said 14-16 which is 5-100 weight part.

18. The ratio of the amount of the positive electrode active material to the amount of the ion conductive polymer in the electrolyte composition for secondary batteries is such that the amount of the positive electrode active material is 10 to 5, with respect to 100 parts by weight of the ion conductive polymer. The composition for positive electrode formation in any one of said 14-17 which is 000 weight part.
19. 18. A positive electrode film obtained by molding the positive electrode forming composition as described in any one of 14 to 17 above.
20. 14. A secondary battery having the electrolyte film according to 13 above as a constituent element.

21. 20. A secondary battery having a laminate of the positive electrode film described in 19 and the electrolyte film described in 13 above as constituent elements.
22. The positive electrode current collector is provided on the positive electrode film surface side, and the negative electrode current collector is provided on the negative film side with respect to the laminate having a structure in which the positive electrode film is laminated on one side of the electrolyte film and the negative electrode film is laminated on the other side. Secondary batteries that are arranged and configured.

According to the present invention, an electrolyte composition for a secondary battery that gives a film having high ionic conductivity and transport number and excellent interlayer adhesion, an electrolyte film comprising the composition, and having a high capacity stably by having the electrolyte film. A secondary battery as shown is provided.

The electrolyte composition for secondary batteries of the present invention comprises an organic compound represented by the following general formula (1), an ion conductive polymer, and an electrolyte salt compound.
M (OR ¹ ) (OR ² ) (OR ³ ) (1)
M is a group 3B element of the periodic table; one or two of R ¹ , R ² and R ³ is (CH ₂ CH ₂ O) _n R ⁴ , and the other two or one is Si (R ⁵ ) (R ⁶ ) represents (R ⁷ ). R ⁴ is an alkyl group, alkenyl group, phenyl group or alkylphenyl group; R ⁵ , R ⁶ and R ⁷ are alkyl group, alkenyl group, phenyl group or alkylphenyl group, alkyloxy group, alkenyloxy group, phenyl An oxy group, an alkylphenyloxy group, a fluoroalkyl group, an acryloxyalkyl group, a methacryloxyalkyl group, or a nitrogen-containing alkylene group; n is an integer of 1 to 50;

  As M in the general formula (1), boron and aluminum are preferable among the group 3B elements. Boron is most preferred.

  The organic compound represented by the general formula (1) is a positive electrode film that is dissolved in an ion conductive polymer to make a molded body flexible by expressing the action of a plasticizer, and is laminated on the surface of an electrolyte film described later. The adhesion is also improved when a negative electrode film is laminated on the back surface. Furthermore, it has the effect | action which improves the ion mobility in an electrolyte film.

Although the preparation method of the organic compound represented by the general formula (1) is not limited, the metal oxide [M ₂ O ₃ ] or the metal trialkyl ester [M- (OR) ₃ ] and alkoxy polyethylene glycol are used in the first reaction. An intermediate product M (OR ⁸ ) (OR ⁹ ) OH is synthesized from [R ′ (OCH ₂ CH ₂ ) nOH] and then, as a second reaction, a small amount of water is added to the —OH group of the intermediate product. A process in which (R ¹⁰ ) Si (R ⁵ ) (R ⁶ ) (R ⁷ ) is allowed to act in the presence to replace all —OH groups with —OSi (R ⁵ ) (R ⁶ ) (R ⁷ ). It is preferable to take. Here, R and R ′ are alkyl groups having 1 to 30 carbon atoms, R ⁸ is (CH ₂ CH ₂ O) _n R ⁴ , and R ⁹ is H or (CH ₂ CH ₂ O) _n R ⁴ . The molecular weight of the alkoxy polyethylene glycol is preferably 150 to 1,500, more preferably 200 to 1,300, and particularly preferably 250 to 1,200. R ⁴ , R ⁹ and integer n can be appropriately adjusted depending on the type of the alkoxy polyethylene glycol used. n is an integer of 1 to 50, preferably an integer of 4 to 29, and more preferably an integer of 5 to 27.

R ⁵ , R ⁶ and R ⁷ are an alkyl group, alkenyl group, phenyl group or alkylphenyl group, alkyloxy group, alkenyloxy group, phenyloxy group, alkylphenyloxy group, fluoroalkyl group, acryloxyalkyl group , A methacryloxyalkyl group or a nitrogen-containing alkylene group, preferably an alkyloxy group, particularly preferably a methoxy group or an ethoxy group.
R ¹⁰ is preferably an alkyl group, an alkylphenyl group, an alkyloxy group, an alkenyloxy group, a phenyloxy group or an alkylphenyloxy group, more preferably an alkyl group or an alkylphenyl group, and particularly preferably an alkyl group.
Here, the R ^5, R ^6, carbon atoms in the alkyl group and alkenyl group in R ⁷ and R ¹⁰ is 1-20.

Further, this substitution reaction may be performed simultaneously with the mixing of the ion conductive polymer and / or the electrolyte salt compound. As a specific method thereof, an ion-conductive polymer is combined with M (OR ⁸ ) (OR ⁹ ) OH as the intermediate product and (R ¹⁰ ) Si (R ⁵ ) (R ⁶ ) (R ⁷ ). And the method of allowing the substitution reaction to proceed while kneading, and the method of further blending the electrolyte salt compound during the previous compounding and then allowing the substitution reaction to proceed while kneading.

The content of the organic compound represented by the general formula (1) in the electrolyte composition for a secondary battery of the present invention is preferably 10 to 400 parts by weight, more preferably 15 to 100 parts by weight per 100 parts by weight of the ion conductive polymer. 250 parts by weight, particularly preferably 20 to 200 parts by weight.
When there is too little content of this organic compound, the obtained electrolyte film cannot have desired ionic conductivity and a transport number, and there exists a possibility that it may be inferior to the interlayer adhesiveness with a positive electrode film or a negative electrode film. On the other hand, if the amount is too large, the electrolyte film has low rigidity, so that it is inferior in its self-supporting property and may have increased adhesiveness.

  The ion conductive polymer used in the present invention is not particularly limited, and any polymer can be used as long as it generally has ion conductivity. The weight average molecular weight (Mw) of the ion conductive polymer is preferably 5,000 to 5,000,000, more preferably 10,000 to 2,000,000, particularly preferably 20,000 to 1,000,000. 000 range. If Mw is too low, the strength of the obtained electrolyte film may be weakened. On the other hand, if it is too high, the viscosity at the time of kneading may be high, which may cause a decrease in productivity.

The structure of the ion conductive polymer is not particularly limited, but an organic polymer having an alkylene oxide structure or a carbonate structure in the main chain or side chain is preferable.
Examples of the organic polymer having an alkylene oxide structure in the main chain include polyether polymers. Examples of the organic polymer having a carbonate structure in the main chain include alkylene carbonate-based polymers. Examples of the organic polymer having an alkylene oxide structure in the side chain include a polymer of alkoxy polyethylene glycol methacrylate and a polymer of phenoxy polyethylene glycol acrylate. Examples of the organic polymer having a carbonate structure in the side chain include vinylene carbonate-based polymers, vinyl ethylene carbonate-based polymers, ethylene carbonate methacrylate-based polymers, and the like.
Among these various ion conductive polymers, organic polymers having an alkylene oxide structure or a carbonate structure in the main chain are preferable.

The polyether polymer is not limited as long as it has an alkylene oxide repeating unit obtained by ring-opening polymerization of an oxirane monomer as a main structural unit. However, ethylene oxide and other copolymerizable with ethylene oxide can be used. A copolymer with an oxirane monomer is preferred. An electrolyte film obtained by molding a polymer using at least an ethylene oxide monomer as one component is excellent in mechanical strength.
The ratio of the repeating unit of the ethylene oxide monomer (a) in the preferred polyether polymer to the repeating unit of the other oxirane monomer (b) copolymerizable with ethylene oxide is preferably 50 to 100. The mol% is 0 to 50 mol%, more preferably 85 to 99 mol% to 15 to 1 mol%, and particularly preferably 90 to 99 mol% to 10 to 1 mol%. If the ethylene oxide monomer (a) unit content is too small, the electrolyte film may easily adhere to a cooling roll or the like.

  Other oxirane monomers (b) copolymerizable with ethylene oxide include alkylene oxides having 3 to 20 carbon atoms, glycidyl ethers having 4 to 10 carbon atoms, oxides of aromatic vinyl compounds, and these oxirane monomers. And a crosslinkable oxirane monomer into which a crosslinkable functional group such as a vinyl group, a hydroxyl group or an acid anhydride group is introduced.

  Other oxirane monomers (b) copolymerizable with ethylene oxide may be used alone or in combination of two or more, but in the present invention, the above-mentioned 3 to 20 carbon atoms are used. Are preferably used as at least one component thereof, and more preferably 3 to 20 alkylene oxides are used as at least one component thereof. Among the alkylene oxides having 3 to 20 carbon atoms, propylene oxide is preferable.

Examples of the crosslinkable oxirane monomer include oxirane monomers such as alkylene oxides having 3 to 20 carbon atoms and glycidyl ether having 4 to 10 carbon atoms, and light such as vinyl groups, hydroxyl groups, and acid anhydride groups. Alternatively, it is preferable to use a crosslinkable oxirane monomer having a crosslinkable group that can be crosslinked with peroxide, and among them, it is more preferable to use a crosslinkable oxirane monomer having a vinyl group such as vinyl glycidyl ether and allyl glycidyl ether. preferable.

  The polymerization catalyst for ring-opening polymerization of the oxirane monomer is not particularly limited. For example, a catalyst obtained by reacting water and acetylacetone with organic aluminum (Japanese Patent Publication No. 35-15797), triisobutylaluminum A catalyst obtained by reacting phosphoric acid with triethylamine (Japanese Patent Publication No. 46-27534), a catalyst obtained by reacting triisobutylaluminum with an organic acid salt of diazaviacyclooundecene and phosphoric acid (Japanese Patent Publication No. 56-51171) ), A catalyst comprising a partially hydrolyzed aluminum alkoxide and an organic zinc compound (Japanese Patent Publication No. 43-2945), a catalyst comprising an organic zinc compound and a polyhydric alcohol (Japanese Patent Publication No. 45-7751), Ring-opening weight of oxirane compounds such as catalysts composed of dialkylzinc and water (Japanese Patent Publication No. 36-3394) It may be a conventionally known polymerization catalyst as the catalyst.

As a polymerization method for obtaining the polyether polymer, a polymerization method such as a solution polymerization method using an organic solvent in which the produced polymer is dissolved or a solvent slurry polymerization method using an organic solvent in which the produced polymer is insoluble is used. be able to. A solvent slurry polymerization method using a solvent such as n-pentane, n-hexane, or cyclopentane is preferred.
Among the solvent slurry polymerization methods, a two-stage polymerization method in which seeds are preliminarily polymerized and then the seed particles are enlarged is preferable because the amount of scale attached to the inner wall of the reactor is small.

The electrolyte salt compound used in the present invention is not particularly limited as long as it is soluble in the ion conductive polymer. Examples of the electrolyte salt compound soluble in the ion conductive polymer include halogen ion, perchlorate ion, thiocyanate ion, trifluoromethanesulfonate ion [CF ₃ SO ₃ ⁻ ], bis (trifluoromethanesulfonyl) imide ion [ N (CF ₃ SO ₂ ) ₂ ⁻ ], bis (heptafluoropropylsulfonyl) imide ion [N (C ₂ F ₅ SO ₂ ) ₂ ⁻ ], trifluorosulfonimide ion, tetrafluoroborate ion [BF ₄ ⁻ ], Hexafluorophosphate ion, trifluoromethane sulfonylimide acid ion, nitrate ion, AsF ₆ ⁻ , PF ₆ ⁻ , stearyl sulfonate ion, octyl sulfonate ion and other anions, dodecylbenzene sulfonate ion, etc. The salt which consists of an anion and a metal cation is mentioned.

Examples of the metal forming the metal cation include lithium, sodium, potassium, rubidium, and cesium. Examples include magnesium, calcium and barium. Of these metal cations, lithium ions are preferred.
Among the lithium salts formed by the anions and lithium ions, LiBF ₄ , LiPF ₆ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ and LiN (C ₂ F ₅ SO ₂ ) ₂ are preferable. These electrolyte salt compounds may be used alone or in combination of two or more.

  The content of the electrolyte salt compound in the electrolyte composition for a secondary battery of the present invention is preferably 5 to 70 parts by weight, more preferably 8 to 60 parts by weight, particularly 100 parts by weight of the ion conductive polymer. The amount is preferably 10 to 55 parts by weight. If the content of the electrolyte salt compound is too small, the ionic conductivity of the electrolyte may be lowered. Conversely, if the content is too large, the mechanical strength may be lowered.

The electrolyte composition for a secondary battery of the present invention includes R ¹ , R ^{2 in the} general formula (1), and an organic compound, an ion conductive polymer and an electrolyte salt compound represented by the general formula (1). It is preferable to include a triester compound in which all of R ³ is — (CH ₂ CH ₂ O) _n R ^{4 because} the transport number of the electrolyte film is improved. The content when the electrolyte composition for a secondary battery contains the triester compound is preferably 2 to 80 parts by weight, more preferably 5 to 50 parts by weight, with respect to 100 parts by weight of the ion conductive polymer. Particularly preferred is 7 to 40 parts by weight.

Moreover, when the electrolyte composition for secondary batteries of the present invention contains R ⁴ (OCH ₂ CH ₂ ) _n —Si (R ⁵ ) (R ⁶ ) (R ⁷ ), the self-supporting property of the film is not lowered so much. It is preferable because ion conductivity can be improved. When the electrolyte composition for a secondary battery contains the compound, the content is preferably 5 to 100 parts by weight, more preferably 10 to 80 parts by weight, particularly preferably 100 parts by weight of the ion conductive polymer. Is 15-60 parts by weight.

Moreover, it is preferable that the electrolyte composition for secondary batteries of this invention contains fumed silica. The fumed silica is ultrafine silica and has a specific surface area of 30 to 500 m ² / g by BET method. Of these, hydrophilic ones are preferable. By containing fumed silica, the self-supporting property of the film can be improved without lowering the ionic conductivity and the transport number.
The content of fumed silica in the electrolyte composition for a secondary battery is preferably 3 to 50 parts by weight, more preferably 5 to 45 parts by weight, and particularly preferably 7 to 100 parts by weight with respect to 100 parts by weight of the ion conductive polymer. 40 parts by weight.

The electrolyte composition for secondary batteries of the present invention can be formed into a solid electrolyte molded body by molding or molding and crosslinking. A typical form of the solid electrolyte molded body is an electrolyte film.

  The method for obtaining a crosslinked solid electrolyte molded body is not particularly limited. For example, a crosslinking agent such as a radical initiator, sulfur, mercaptotriazines, or thioureas is blended in an electrolyte composition for a secondary battery and heated. The method of bridge | crosslinking by doing, the method of bridge | crosslinking by irradiating actinic radiation, etc. are mentioned. Among these, a method of crosslinking by heating using a radical initiator such as an organic peroxide or an azo compound, or a method of crosslinking by irradiating active radiation such as ultraviolet rays, visible light, or an electron beam is preferable.

  Examples of the organic peroxide include ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide; 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 2,2-bis (t -Peroxyketals such as butylperoxy) octane and n-butyl-4,4-bis (t-butylperoxy) valerate; t-butyl hydroperoxide, cumene hydroperoxide, 2,5-dimethylhexane Hydroperoxides such as 2,5-dihydroperoxide; di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, α, α'-bis (t-butylperoxy-m- Isopropyl) benzene, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, 2,5 -Dialkyl peroxides such as dimethyl-2,5-bis (t-butylperoxy) hexyne; diacyl peroxides such as benzoyl peroxide; peroxyesters such as t-butyl peroxyacetate.

  Examples of the azo compounds include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile). ), 2,2′-azobis (2,4-dimethylvaleronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2- (carbamoylazo) isobutyronitrile, 2-phenylazo-4- Azonitrile compounds such as methoxy-2,4-dimethyl-valeronitrile; 2,2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide}, 2, 2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide}, 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], etc. Azoami 2,2′-azobis (2-methyl-N-phenylpropionamidine) dihydrochloride, 2,2′-azobis [N- (4-chlorophenyl) -2-methylpropionamidine] dihydrochloride, 2, 2′-azobis [N- (hydroxyphenyl) -2-methylpropionamidine] dihydrochloride, 2,2′-azobis [2-methyl-N- (phenylmethyl) propionamidine] dihydrochloride, 2,2 ′ -Azobis [2-methyl-N- (2-propenyl) propionamidine] dihydrochloride, 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis [N- (2- And azoamidine compounds such as hydroxyethyl) -2-methylpropionamidine] dihydrochloride.

The amount of the crosslinking agent is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 7 parts by weight, and particularly preferably 0.3 to 5 parts by weight with respect to 100 parts by weight of the ion conductive polymer. Part.
In the electrolyte composition for a secondary battery of the present invention, a crosslinking aid can be used together with a crosslinking agent as necessary.

  For example, as a crosslinking aid used in combination with an organic peroxide crosslinking agent or an azo compound crosslinking agent, metal oxides such as zinc oxide and magnesium oxide; metal hydroxides such as calcium hydroxide; zinc carbonate, basic carbonate Metal carbonates such as zinc; fatty acids such as stearic acid and oleic acid; fatty acid metal salts such as zinc stearate and magnesium stearate;

Moreover, when using an organic peroxide as a crosslinking agent, the compound which has at least 2 crosslinkable unsaturated bond in a molecule | numerator can be mix | blended as a crosslinking adjuvant. Specific examples thereof include ethylene dimethacrylate, diallyl phthalate, N, Nm-phenylene dimaleimide, triallyl isocyanurate, trimethylolpropane trimethacrylate, liquid vinyl polybutadiene, and the like.
These crosslinking aids may be used in combination of two or more.

  The amount of the crosslinking aid used is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and particularly preferably 10 parts by weight or less with respect to 100 parts by weight of the ion conductive polymer. When there are too many crosslinking aids, the crosslinking rate may become too fast at the time of crosslinking, bloom on the surface of the crosslinked product may occur, or the crosslinked product may become too hard.

  When performing crosslinking by active radiation such as ultraviolet rays or electron beams, a photocrosslinking agent may be added as necessary. Examples of the photocrosslinking agent include benzyl dimethyl ketal, trimethylsilyl benzophenone, benzoin, 4-methoxybenzophenone, benzoin methyl ether anthraquinone, and the like.

  For the purpose of improving the ionic conductivity of the electrolyte film, an organic solvent or a plasticizer may be added to the electrolyte composition for a secondary battery of the present invention. As the organic solvent, aprotic esters and ethers are preferable. The plasticizer is preferably tetrahydrofuran or a polyalkylene glycol derivative having a molecular weight of 5,000 or less. Specific examples of the latter include propylene carbonate, ethylene carbonate, butylene carbonate, ethylene glycol diethyl ether and the like.

  When molding the electrolyte composition for a secondary battery of the present invention, the organic compound represented by the general formula (1), the ion conductive polymer, the electrolyte salt compound, and the above-mentioned compounding agent added as necessary. In addition, it is possible to adopt a method of mixing in advance by a known method using a roll or a Banbury mixer and then forming by pressing. As another method, for example, the above-mentioned compounding agents may be added and mixed in an extruder or the like and molded while being extruded with a T-die or the like. The mixing order of the above-mentioned components at the time of mixing is not limited. However, after sufficiently mixing components that are not easily decomposed by heat, components (for example, a crosslinking agent, a crosslinking accelerator, etc.) that are easily reacted and decomposed by heat are briefly added. It is preferable to mix with. When an organic solvent or a plasticizer is added, it may be added simultaneously with mixing, or it may be impregnated for a long time after molding and crosslinking.

  Examples of the shape of the molded body obtained by molding the electrolyte composition for a secondary battery include a plate shape, a sheet shape, and a film shape, but a film is used when used as a solid electrolyte of a battery such as a lithium secondary battery. It is preferable to use as. As a film forming method, an extrusion molding method, a press molding method, an injection molding method, a solution casting method, or the like can be used. Among these, the extrusion method is preferable from the viewpoint of the surface accuracy and productivity of the obtained film. Moreover, when the electrolyte film is formed by an extrusion method, it is particularly preferable to employ a die extrusion method using a twin screw extruder. Depending on the molding method, the crosslinking method, the shape of the crosslinked product, and the like, the molding and the crosslinking may be performed simultaneously or after the molding.

  The temperature of the extruder kneading part for stably producing the electrolyte film is usually 40 to 200 ° C, preferably 50 to 150 ° C, more preferably 55 to 130 ° C. If the temperature of the kneading part is too low, there is a risk that the dispersion of the compound will be poor and the battery characteristics will deteriorate, and conversely if the temperature of the kneading part is too high, the compound will undergo thermal decomposition and the battery characteristics may be deteriorated. There is sex.

  The electrolyte film extruded from the die of the extruder is usually wound around a take-up roll through a cooling roll. It is preferable to place a cast roll in front of the take-up roll, detect the thickness and tension of the film with the respective detecting means, and feed back the results to the extruder and the cooling roll. The thickness of the electrolyte film controlled by the cast roll is preferably 10 to 100 μm, more preferably 15 to 90 μm, and particularly preferably 18 to 80 μm. If the thickness of the electrolyte film is too thin, it may break or stick, and conversely, if it is too thick, the distance between the positive electrode and the negative electrode will increase and the battery impedance will increase, resulting in battery characteristics. May be reduced.

  The secondary battery of the present invention has a positive electrode current collector on the positive electrode film surface side and a negative electrode film side on the negative electrode film side of the laminate having a structure in which the positive electrode film is laminated on one side of the electrolyte film and the negative electrode film is laminated on the other side. Each of the negative electrode current collectors is arranged.

  The positive electrode film is formed by forming a composition containing a positive electrode active material, a conductivity-imparting agent and a binder into a film shape. Binders include acrylic polymers (for example, 2-ethylhexyl acrylate, acrylic acid and acrylonitrile copolymers), fluorine-containing polymers, polyether polymers, polyacrylonitrile, ethylene-vinyl alcohol copolymers, cellulose, acrylonitrile-butadiene. Examples include hydrides of copolymers.

As a positive electrode active material, if it is an active material used for the positive electrode of a battery, it can be used without limitation. Examples of such positive electrode active materials include lithium cobalt oxide, lithium manganate, lithium titanate, lithium manganese composite oxide, LiNiO ₂ , lithium vanadium composite oxide, lithium-containing composite metal oxides such as LiFePO ₄ ; titanium sulfide, Transition metal oxides such as molybdenum sulfide, V ₂ O ₅ , V ₆ O ₁₃ , and molybdenum oxide; lithium manganate, lithium nickelate and lithium cobaltate are preferred.
The average particle diameter of the positive electrode active material is 0.1 to 30 μm, preferably 0.5 to 20 μm. If the average particle size of the positive electrode active material is too large or too small, the positive electrode active material may not be uniformly mixed with the ion conductive polymer, or the mixed solution (coating solution) may be difficult to mix.

The conductivity imparting agent is a substance that assists the conductive characteristics of the active material, and carbon particles are usually used. Any carbon particles can be used as long as they are used for the positive electrode of a battery. Examples of such carbon particles include carbon black, acetylene black, ketjen black, and graphite.
The average particle size of such carbon particles is preferably 10 to 80 nm, more preferably 20 to 50 nm. If the average particle size of the carbon particles is too small, it may not be uniformly dispersed in the active material. Conversely, if the carbon particles are too large, the surface of the positive electrode film will be uneven and the adhesion to the electrolyte film or positive electrode current collector will be reduced. Battery output may be reduced or the battery may be easily broken.

In addition, the carbon particles preferably have a moderately large oil absorption amount from the viewpoints of blending amount and conductivity, and the dibutyl phthalate (DBP) absorption amount is usually 100 to 500 ml / g, preferably 150 to 400 ml / g.

  The content of the conductivity-imparting agent, particularly the carbon particles, in the positive electrode film is preferably 1 to 30 parts by weight, more preferably 2 to 15 parts by weight, and particularly preferably 2.5 to 12 parts per 100 parts by weight of the positive electrode active material. Parts by weight. If the carbon particle content is too small, the battery reaction of the active material cannot be effectively used and the battery capacity may be lowered. If the carbon particle content is too large, the thickness of the positive electrode layer is difficult to be uniform, and the battery capacity per unit weight is low. May be reduced.

The positive electrode film can contain the electrolyte composition of the present invention in addition to the positive electrode active material and the conductivity-imparting agent. In this case, the aforementioned ion conductive polymer also functions as a binder.
In this case, the content of the positive electrode active material in the positive electrode film is preferably 10 to 5000 parts by weight, more preferably 30 to 2000 parts by weight with respect to 100 parts by weight of the ion conductive polymer in the electrolyte composition of the present invention. The amount is particularly preferably 50 to 1000 parts by weight. If the content of the positive electrode active material is too small, the function as the positive electrode may be insufficient. Conversely, if the content is too large, the active material in the positive electrode film may be poorly dispersed.

When the composition for forming a positive electrode film contains the electrolyte composition of the present invention, since the organic compound represented by the general formula (1) is present, the obtained positive electrode film has adhesiveness with the electrolyte film or the current collector. And the secondary battery is more stable and exhibits a high capacity, which is preferable. When the composition for forming a positive electrode film contains the organic compound, the content is preferably 5 to 100 parts by weight, more preferably 10 to 80 parts by weight, and particularly preferably 15 parts with respect to 100 parts by weight of the positive electrode active material. -70 parts by weight.

  The method for forming the positive electrode film is not necessarily limited, but the following three methods are typical. As a first method, a positive electrode active material and a conductivity-imparting agent are mixed with an organic solvent solution or an aqueous dispersion of a polymer as a binder to form a slurry composition, which is a collection of a metal foil such as an aluminum foil. For example, a method may be used in which a film is formed by uniformly applying to an electric body with a doctor blade and drying. Examples of the polymer serving as the binder include acrylate polymers, fluorine-containing polymers (such as polyvinylidene fluoride), styrene-butadiene polymers, and acrylonitrile-butadiene polymers. When the positive electrode film is produced by a coating method, the content of the binder is preferably 0.5 to 20 parts by weight, more preferably 1 to 15 parts by weight, and particularly preferably 1 to 100 parts by weight of the positive electrode active material. 5 to 12 parts by weight.

  As the second forming method of the positive electrode film, various components obtained by adding the above-described positive electrode active material and the conductivity imparting agent to the above-described electrolyte composition for a secondary battery are mixed with a brabender, a Banbury mixer, a roll, or the like. There is a method in which a clay-like kneaded product is cut with scissors and formed into a film or sheet with a hot press. The pressing condition is, for example, about 5 minutes at 120 ° C. under a pressure of 8 MPa.

  As a third forming method of the positive electrode film, there is a method of forming the above ion-conductive polymer into a film shape by an extruder. At that time, a positive electrode active material, a conductivity-imparting agent, an organic compound represented by the general formula (1), an electrolyte salt compound, or the like is previously mixed with the polymer, or a second feed port provided in the middle of the barrel The extruded film is mixed, and the extruded film is accommodated on a support film such as a polyester film. According to the extrusion method, it is easy to produce a thin film.

When the positive electrode film is formed by an extrusion method, an anti-aging agent, a light stabilizer, a lubricant, a flame retardant, an antifungal agent, an antistatic agent, a colorant, and a reinforcing material are further added to the ion conductive polymer as necessary. It is preferable to mix various components to which a filler or the like is added and to provide the mixture to an extruder.
The temperature of the extruder kneading part for stably producing the positive electrode film with an extruder is preferably 40 to 200 ° C, more preferably 60 to 190 ° C, and particularly preferably 70 to 180 ° C. If the temperature of the kneading part is too low, there is a risk that the dispersion of the compound will be poor and the battery characteristics will deteriorate, and conversely if the temperature of the kneading part is too high, the compound will undergo thermal decomposition and the battery characteristics may be deteriorated. There is sex.

When the positive electrode film is formed by a coating method, the thickness is preferably 10 to 200 μm, more preferably 20 to 150 μm, and particularly preferably 30 to 120 μm.
When a positive electrode film is shape | molded by the press method or an extrusion method, the thickness becomes like this. Preferably it is 10-200 micrometers, More preferably, it is 20-120 micrometers, Most preferably, it is 30-100 micrometers. If the thickness of the positive electrode film is too thin, the film handling property (handling property) may be inferior. On the other hand, if it is too thick, the adhesion to other films that come into contact with the film will be reduced, and cracking will occur when folded. In some cases, the output of a battery is low.

As the positive electrode current collector, an aluminum foil is usually used. The shape of the positive electrode current collector is not particularly limited, but a film shape of about 5 to 300 μm is preferably used.
In the present invention, the negative electrode film is known as a negative electrode of a secondary battery, and a layer containing a negative electrode active material and a binder, or a layer made of a metal foil can be used.

As the negative electrode active material, an organic or inorganic material that absorbs and releases lithium can be used. For example, in addition to the carbon-based material, transition metal oxides such as titanium and vanadium, silicon compounds, and the like can be used. Among these, carbon-based materials are particularly preferable, and mesocarbon microbeads that are spherical graphite, scaly graphite, massive graphite, non-graphitizable carbon, low crystalline carbon, low-temperature calcined carbon, and the like can be used. These carbon-based materials include lithium alloys with aluminum, silicon, lead, tin, zinc, etc., transition metal composite oxides such as LiFe ₂ O ₃ , transition metal oxides such as MnO ₂ , silicon such as SiO _2, etc. An oxide, lithium nitride such as Li ₅ N, or metal lithium may be mixed.

Preferred binders for the negative electrode film include the same binders as those used for the positive electrode film, and among them, acrylic polymers and fluorine-containing polymers are preferred. The amount of the binder used is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 8 parts by weight, and particularly preferably 0.5 to 6 parts by weight with respect to 100 parts by weight of the negative electrode active material. If the amount of the binder used is too small, the mechanical strength of the coating film is insufficient, and the negative electrode active material may fall off the current collector. Conversely, if the amount is too large, the internal resistance will increase and the cycle performance of the battery will increase. May be reduced.

  A negative electrode film containing a negative electrode active material and a binder is produced by uniformly applying a slurry composition shown below to a current collector with a doctor blade or the like and drying. The slurry composition is prepared by mixing solid particles such as a negative electrode active material, a viscosity modifier and the like in an organic solvent in which a binder is dispersed. The thickness of the negative electrode film in this case is preferably 5 to 300 μm, more preferably 10 to 200 μm, and particularly preferably 20 to 160 μm.

A copper foil is preferably used as the negative electrode current collector. In general, the negative electrode current collector is preferably a film of about 3 to 300 μm.
When the negative electrode film is made of a metal foil, preferred metals are lithium, lithium-aluminum alloy, lithium-indium alloy, etc., with lithium being particularly preferred. The thickness of the negative electrode film in the case of metal foil is preferably 1 to 500 μm, more preferably 3 to 300 μm, and particularly preferably 5 to 250 μm.

There is no restriction | limiting in the method of laminating | stacking said positive electrode film, electrolyte film, and negative electrode film in this order, and comprising the laminated body for batteries. Usually, three layers are stacked and pressure-bonded by a biaxial roll, a calender roll, a biaxial roll press, etc. In the present invention, at the time of lamination, it is represented by the general formula (1) at the lamination interface between the positive electrode film and the electrolyte film. It is preferable to interpose an organic compound layer. There is no limitation on the method of interposing the organic compound layer on the laminate interface between the positive electrode film and the electrolyte film. For example, spin coating, dip, tape casting, extrusion coating, reversing roller, doctor blade, wire on one of the interfaces of both films Various coating methods such as a bar, a bar coater, and an applicator can be employed. Alternatively, the organic compound may be supplied to one side of the interface by spraying, ink jetting, dot printing, screen printing, or the like, and spread with a squeezer, roller, brush, or the like as necessary.
The thickness of the organic compound layer is preferably 0.005 to 100 μm, more preferably 0.01 to 80 μm, and particularly preferably 0.1 to 60 μm.

  The surface temperature of the roller when the laminate of the positive electrode film, the electrolyte film and the negative electrode film is pressure-bonded is preferably 30 to 120 ° C, more preferably 35 to 100 ° C, and particularly preferably 40 to 90 ° C. If the surface temperature of the roller is too low, the adhesiveness of the laminate may be insufficient and may be easily peeled off. Conversely, if the roller surface temperature is too high, the thickness of the laminate may fluctuate greatly, or the thickness may become too thin. The strength may decrease.

  As another method of the above laminating operation, three layers of a positive electrode film, an electrolyte film, and a negative electrode film, preferably, an organic compound layer represented by the general formula (1) is further added to the interface between the positive electrode film and the electrolyte film to form four layers. Prior to lamination, a positive electrode current collector is previously laminated on the side of the positive electrode film not in contact with the electrolyte film by a roller, a press, etc., and / or a negative electrode current collector in advance on the side of the negative electrode film not in contact with the electrolyte film. May be laminated with a roller, a press, etc., and then the procedure for performing the above-mentioned pressure bonding may be taken.

The three-layer or four-layer laminate used in the present invention is characterized in that the adhesion between the layers is good and the thickness of the laminate is small.
The secondary battery of the present invention formed by laminating a positive electrode current collector on the positive electrode film side of the laminate and laminating a negative electrode current collector on the negative film side is the electrolyte composition for secondary battery of the present invention. An electrolyte film having a high ion conductivity and a high transport number is used as a constituent element. Preferably, the positive electrode film of the constituent element also contains the electrolyte composition for a secondary battery of the present invention. The variation is small. In particular, the electrolyte film is composed of lithium salts such as LiBF ₄ , LiPF ₆ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ and LiN (C ₂ F ₅ SO ₂ ) ₂ as the electrolyte salt compound of the electrolyte film. The lithium ion secondary battery has a remarkably high initial capacity and excellent charge / discharge cycle characteristics, and is effective in forming a coin battery type polymer battery.

  Hereinafter, the present invention will be described more specifically with reference to production examples, examples and comparative examples, but the present invention is not limited thereto. “Part” is based on weight unless otherwise specified. The test and evaluation were performed according to the following methods.

(1) Electrochemical characteristics of electrolyte film “Ionic conductivity” is determined by an alternating current method in which an electrolyte film having a diameter of 15 mm is sandwiched between two stainless steel electrodes, a temperature of 50 ° C., a voltage of 0.5 V, and a frequency range of 5 Hz to 13 MHz. Measured by the complex impedance method. The unit is (S / cm) × 10 ⁻⁵ .
“Transport number” was measured by the AC impedance / DC polarization method at a temperature of 50 ° C. with a new electrolyte film of 15 mm sandwiched between two lithium metal foils. Unit is a dimensionless number from 0 to 1.

(2) Bonding Characteristics of Electrolyte Film (Support Film Peelability, SUS Plate Bondability) “Support film peelability” was evaluated based on the peeled state of the support film (made of polyethylene terephthalate) after press molding.
○: Easy to peel off.
Δ: adheres but does not break if peeled off slowly.
X: Strong adhesion and partial tearing even if slowly peeled off.
The “SUS plate bonding property” was evaluated based on the situation when the electrolyte film was directly bonded to the stainless steel plate.
○: Can be applied without wrinkles, and there is no adhesion failure.
Δ: Slight wrinkles or poor adhesion in a small part ×: Wrinkles or poor adhesion.

(3) Battery characteristics (initial capacity, initial capacity fluctuation, capacity after 20 cycles)
The battery capacity was measured after applying a predetermined charge / discharge voltage (charge / discharge voltage difference of 1.5 V) twice by a constant current method at 60 ° C. with a charge / discharge rate of 0.2C. Battery capacity was measured for 10 coin-type batteries produced using 10 test pieces per test object. As the initial battery capacity, an average value of five values having larger capacities was used. The unit is [mAh / g-active material]. In addition, the fluctuation of the initial capacity was a value obtained by dividing the difference between these five maximum values and minimum values by the initial battery capacity. Units〔%〕.
A predetermined charge / discharge voltage was applied twice to the battery, and after the initial capacity measurement, the application (that is, the charge / discharge cycle) was further repeated to measure the 20th capacity. An average value was obtained for the above five batteries showing a large initial battery capacity, and was defined as “capacity after 20 cycles”.
(4) The weight average molecular weight (Mw) was measured by GPC.
(5) For the polymer composition, the polymer was dissolved in deuterated chloroform, the integral value of each unit was determined by ¹ H-NMR, and the composition ratio was determined from the calculation result.
Device: JNM-EX400 type (manufactured by JEOL Datum)

Production Example 1 Production of Organic Compound a While stirring in a 100 ml eggplant flask at room temperature in a dry air atmosphere, 42 g (0.12 mol) of polyethylene glycol methyl ether (manufactured by Aldrich, molecular weight 350) and triethyl borate (Kanto) 11.7 g (0.08 mol) of Chemical Co., Ltd. was added. After completion of the addition, the temperature was raised to 70 ° C. and reacted for 3 hours. Thereafter, the system is gradually cooled to 40 ° C. while stirring, and then the pressure inside the system is gradually reduced and kept at 20 to 30 mmHg (2.7 to 4.0 kPa) for 1 hour. The triethyl borate was removed to obtain a boron ester precursor b.
Next, 11.9 g (0.058 mol) of hexyltrimethoxysilane (product name “KBM3063”, manufactured by Shin-Etsu Chemical Co., Ltd.) is added to 26.5 g (0.050 mol) of the precursor b at room temperature in a dry air atmosphere. Was added. After completion of the addition, the temperature was raised to 90 ° C. and reacted for 5 hours. Thereafter, the system was gradually depressurized and held at 10 to 20 mmHg (1.4 to 2.7 kPa) for 1 hour to remove volatile components accompanying the formation and excess hexyltrimethoxysilane to obtain an organic compound a. .

The infrared absorption spectrum of the organic compound a was measured, and the disappearance of the absorption band derived from the 3440 cm ⁻¹ hydroxyl group was confirmed. The organic compound a is a mixture of two kinds of compounds, and their structures are shown in the following formulas (2) and (3).
B [O (CH ₂ CH ₂ O) ₅ CH ₃ ] [O (CH ₂ CH ₂ O) ₅ CH ₃ ] [OSi (O
_{C 2 H 5) (OC 2} H 5) (C 6 H 13) ] (2) and
B _{[O (CH 2 CH 2 O)} 5 CH 3 ] _{[OSi (OC 2 H 5) (} OC 2 H 5) (C 6 H 13) ] _{[OSi (OC 2 H 5) (} OC 2 H 5) ( C ₆ H ₁₃ )] (3)

Production Example 2 Production of Polyether Polymer P The jacket and the autoclave with a stirrer were dried and purged with nitrogen, and 65.1 parts of triisobutylaluminum, 217.9 parts of toluene and 121.6 parts of diethyl ether were charged. While the internal temperature was set at 30 ° C., 11.26 parts of phosphoric acid was added at a constant rate over 10 minutes. To this, 5 parts of triethylamine was added and aged for 2 hours at 60 ° C. to obtain a catalyst solution. The autoclave was purged with nitrogen, and 1514 parts of n-hexane and 63.3 parts of the catalyst solution were charged. Set the internal temperature to 30 ° C, add 7.4 parts of ethylene oxide with stirring and react, then add 14.7 parts of a mixed monomer such as ethylene oxide and propylene oxide to form a seed. did.

In the polymerization reaction liquid in which the internal temperature was set to 60 ° C. and the seed was formed, 439.6 parts (92 mol%) of ethylene oxide, 25.2 parts (4 mol%) of propylene oxide, 49.5 parts of allyl glycidyl ether (4 mol%) and a mixed solution consisting of 427.4 parts of n-hexane were continuously added at a constant rate over 5 hours. After the addition was complete, the reaction was continued for 2 hours. The polymerization reaction rate was 98%. To the resulting polymer slurry, 42.4 parts of a 5% toluene solution of 4,4′-thiobis (6-tert-butyl-3-methylphenol) as an anti-aging agent was added and stirred. The produced polymer crumb was filtered and then vacuum dried at 40 ° C. to obtain a powdery polyether polymer P.
The composition of the polyether polymer P was 91.6 mol% of ethylene oxide (EO) units, 4.7 mol% of propylene oxide (PO) units, and 3.7 mol% of allyl glycidyl ether. Moreover, the weight average molecular weight (Mw) of this polymer was 310,000.

(Production Example 3) Production of polycarbonate polymer Q In a 100 ml two-necked flask, 40 ml of N, N-dimethylformamide (DMF), 2.48 g (0.025 mol) of anhydrous potassium carbonate, 1,6-hexanediol ( 2.95 g (0.025 mol) manufactured by Aldrich) and 4.23 g (0.013 mol) of 1,6-diiodohexane (manufactured by Tokyo Chemical Industry Co., Ltd.) were added. After replacing the inside of the system with carbon dioxide, a rubber balloon filled with carbon dioxide was attached and stirred at 80 ° C. for 5 hours. After completion of the reaction, the reaction mixture was cooled, ethyl ether and 0.5 M aqueous hydrochloric acid solution were added, and the mixture was separated. The aqueous layer was further extracted twice with ethyl ether, and the organic layers were combined and separated and washed once with 1M aqueous sodium sulfite solution and twice with saturated brine. Anhydrous magnesium sulfate was added to the obtained organic layer and allowed to stand, and then anhydrous magnesium sulfate was filtered off to obtain a dehydrated polycarbonate precursor solution.
To the above solution, 107 g (0.80 mol) of trimethylolpropane (manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.25 g of lithium methoxide were added and stirred at room temperature for 4 hours. Thereafter, the solvent was removed to obtain a polycarbonate polymer Q. Mw of the polycarbonate polymer Q was 38,000.

Example 1
100 parts of a polyether polymer P, bis (trifluoromethanesulfonyl) imidolithium [LiN (CF ₃ SO ₂ ) ₂ ] (LiN (CF ₃ SO ₂ ) ₂ ) (manufactured by Kishida Chemical Co., Ltd., hereinafter “LITFSI” 30 parts), fumed silica (product name “AEROSIL 200V”, manufactured by Nippon Aerosil Co., Ltd., average primary particle size 12 nm), 10 parts, UV crosslinking agent 2,2-dimethoxy-1,2-diphenylethane 1 part of -1-one (product name “Irgacure 651”, manufactured by Ciba Specialty Chemicals) and 30 parts of organic compound a were added and kneaded to obtain an electrolyte composition for a secondary battery. This was press-molded at 70 ° C. while sandwiching both sides with a PET support film (product name “Diafoil”, manufactured by Mitsubishi Chemical Corporation, thickness 25 μm) to obtain an uncrosslinked electrolyte film having a thickness of 32 μm. The obtained film was irradiated with UV at an irradiation amount of 100 mJ / cm ² to obtain a crosslinked film. Table 1 shows the results of testing the electrochemical characteristics and the bonding characteristics of the film from which the support film was peeled off.

(Example 2)
The same procedure as in Example 1 was conducted except that the polyether polymer P was replaced with the polycarbonate polymer Q in Example 1, the amount of LITFSI was reduced from 30 parts to 15 parts, and no UV crosslinking agent was used. An electrolyte film having a thickness of 47 μm was wound up while sandwiching both sides with the support film made. Table 1 shows the results of testing the electrochemical characteristics and bonding characteristics of the film.

(Comparative Example 1 and Comparative Example 3)
In Example 1 or Example 2, except that the organic compound a was not added, the same procedure as in Example 1 or Example 2 was performed, and an electrolyte film having a thickness of 36 μm and 45 μm was wound while sandwiching both sides with a PET support film. I took it. Table 1 shows the results of testing the electrochemical characteristics and bonding characteristics of each electrolyte film.

(Comparative Example 2)
In Example 1, an electrolyte film having a thickness of 32 μm was wound up in the same manner as in Example 1 except that the same amount of propylene carbonate as a plasticizer was added in place of the organic compound a while sandwiching both surfaces with a PET support film. Table 1 shows the results of testing the electrochemical characteristics and bonding characteristics of the film.

  As Table 1 shows, the electrolyte film obtained from the electrolyte composition for a secondary battery according to the present invention containing the organic compound a, the ion conductive polymer and the electrolyte salt compound has high ion conductivity and transport number. In addition to having excellent electrochemical properties, it can be easily peeled off from a PET support film and can be plied to a SUS plate, making it easy to produce a film laminate and interlaminar adhesion. (Examples 1 and 2).

On the other hand, in Comparative Example 1 in which the organic compound a is not added to the polyether polymer P and Comparative Example 3 in which the organic compound a is not added to the polycarbonate polymer Q, the ionic conduction of the obtained electrolyte film is the same. In Comparative Example 1, the film was hard and had poor adhesion with the SUS plate (Comparison between Comparative Example 1 and Example 1, and Comparative Example 3 and Example 2). Contrast).
Even when propylene carbonate was blended in place of the organic compound a, the effect of improving the ionic conductivity was small and there was no effect of improving the transport number (Comparison with Comparative Example 2 and 1 and Example 1).

(Example 3)
100 parts of polyether polymer P at the first feed port of the twin screw extruder (screw diameter 25 mm, screw rotation speed 150 rpm, L / D = 30), and ketjen black (product name ketjen black) at the second feed port EC, Lion Corporation, average particle size 35 nm, DBP absorption 350 ml / g) 15 parts and active material Li _0.33 MnO ₂ (Chuo Denki Kogyo Co., Ltd. average particle size 0.5 μm) 300 parts of mixture mixed in a Henschel mixer In addition, 30 parts of LITFSI were supplied and extruded into a film shape with a coat hanger die (temperature conditions: inlet barrel temperature 30 ° C., central barrel 160 ° C., head 140 ° C., die temperature 140 ° C.). The both sides of the extruded film were sandwiched between support films made of PET and wound on a winding roll via a cast roll to obtain a positive electrode film having a thickness of 80 μm.

A polypropylene gasket (outer diameter 20 mm, inner diameter 16 mm, thickness 3 mm) was placed on the joint surface of the stainless steel container (diameter 20 mm, depth 3 mm) with the cap, and the positive electrode film was obtained in the container and then obtained in Example 1. A test piece of an electrolyte film and a lithium foil having a thickness of 200 μm was put, a stainless steel disk and a spring were sequentially stacked, and a stainless steel cap was put on to close the battery, so that a coin-type battery having a thickness of about 3.2 mm was formed. A total of 10 identical coin-type batteries were produced.
Table 2 shows the results of measuring the initial capacity, the fluctuation of the initial capacity, and the capacity after 20 cycles for the obtained coin-type battery.

(Comparative Example 4)
In Example 3, a coin type battery was obtained in the same manner as in Example 3 except that the electrolyte film obtained in Comparative Example 1 was used instead of the electrolyte film obtained in Example 1. A total of 10 identical coin-type batteries were produced. Table 2 shows the results of a test similar to that of Example 3 performed on the obtained coin-type battery.

(Example 4)
In Example 3, a coin-type battery was obtained in the same manner as in Example 3 except that 30 parts of the organic compound a was mixed with the Henschel mixer mixture supplied to the second feed port of the twin screw extruder.
A total of 10 identical coin-type batteries were produced. Table 2 shows the results of a test similar to that of Example 3 performed on the obtained coin-type battery.

As shown in Table 2, the battery of Example 3 using the electrolyte film containing the organic compound a obtained in Example 1 uses the electrolyte film not containing the organic compound a obtained in Comparative Example 1. Compared to the battery of Comparative Example 4, the initial capacity is large and the fluctuation is small. Further, the battery of Example 3 has a large capacity after 20 cycles and is excellent in capacity retention characteristics.
Moreover, the secondary battery containing not only the electrolyte film but also the positive electrode film of the organic compound a had a smaller capacity fluctuation and a high capacity (Example 4).

The electrolyte composition for a secondary battery of the present invention provides an electrolyte film having high ionic conductivity and transport number and excellent interlayer adhesion. A secondary battery having this electrolyte film stably exhibits a high capacity.
Secondary batteries having this electrolyte film can be widely used. In particular, secondary batteries represented by lithium batteries as power sources for mobile devices such as mobile phones and notebook computers, as well as small electronic and electrical devices. It is highly useful as a battery.

Claims (22)

An electrolyte composition for a secondary battery comprising an organic compound represented by the following general formula (1), an ion conductive polymer and an electrolyte salt compound.
M (OR ¹ ) (OR ² ) (OR ³ ) (1)
Where M is a periodic table group 3B element;
One or two of R ¹ , R ² and R ³ is — (CH ₂ CH ₂ O) _n R ⁴ , and the other two or one is —Si (R ⁵ ) (R ⁶ ) (R ⁷ ). Represents.
R ⁴ represents an alkyl group, an alkenyl group, a phenyl group or an alkylphenyl group;
R ⁵ , R ⁶ and R ⁷ are alkyl group, alkenyl group, phenyl group or alkylphenyl group, alkyloxy group, alkenyloxy group, phenyloxy group, alkylphenyloxy group, fluoroalkyl group, acryloxyalkyl group, methacryloxy An alkyl group or a nitrogen-containing alkylene group;
n is an integer of 1-50. The content of the organic compound and the electrolyte salt compound represented by the general formula (1) is 10 to 400 parts by weight and 5 to 70 parts by weight, respectively, per 100 parts by weight of the ion conductive polymer. An electrolyte composition for a secondary battery.   The electrolyte composition for a secondary battery according to claim 1 or 2, wherein M in the general formula (1) is boron or aluminum. The organic compound represented by the general formula (1) converts all —OH groups in the compound represented by the formula M (OR ⁸ ) (OR ⁹ ) OH to —OSi (R ⁵ ) (R ⁶ ) (R ⁷ ). The electrolyte composition for secondary batteries according to any one of claims 1 to 3, wherein
Here, R ⁸ represents (CH ₂ CH ₂ O) _n R ⁴ , and R ⁹ represents H or (CH ₂ CH ₂ O) _n R ⁴ .   The electrolyte composition for a secondary battery according to any one of claims 1 to 4, wherein the ion conductive polymer is an organic polymer having an alkylene oxide structure or a carbonate structure in a main chain or a side chain.   The ion conductive polymer is a polymer having 50 to 100 mol% of ethylene oxide repeating units and 50 to 0 mol% of repeating units of other oxirane monomers copolymerizable with ethylene oxide. The electrolyte composition for secondary batteries according to any one of 5.   Other oxirane monomers copolymerizable with ethylene oxide are alkylene oxides having 3 to 20 carbon atoms, glycidyl ethers having 4 to 10 carbon atoms, oxides of aromatic vinyl compounds, and crosslinking to these oxirane monomers. The electrolyte composition for a secondary battery according to claim 6, which is at least one selected from crosslinkable oxirane monomers into which a functional group is introduced. The electrolyte composition for a secondary battery according to any one of claims 1 to 7, wherein a weight average molecular weight (Mw) of the ion conductive polymer is in a range of 5,000 to 5,000,000.   Furthermore, 3-50 weight part of fumed silica is contained with respect to 100 weight part of ion conductive polymers, The electrolyte composition for secondary batteries in any one of Claims 1-8. Furthermore, the triester compound in which R ¹ , R ² and R ³ in the general formula (1) are — (CH ₂ CH ₂ O) _n R ⁴ is added in an amount of 2 to 80 with respect to 100 parts by weight of the ion conductive polymer. The electrolyte composition for a secondary battery according to any one of claims 1 to 9, wherein the electrolyte composition is contained in parts by weight. Furthermore, the following general formula _{^{R 4 (OCH 2 CH 2)}} n -Si (R 5) (R 6) (R 7)
The electrolyte composition for secondary batteries in any one of Claims 1-10 formed by containing 5-100 weight part of compounds represented by these with respect to 100 weight part of ion conductive polymers.   Furthermore, 0.1-10 weight part of crosslinking agents are contained with respect to 100 weight part of said ion conductive polymers, The electrolyte composition for secondary batteries in any one of Claims 1-11.   The electrolyte film formed by shape | molding the electrolyte composition for secondary batteries in any one of Claims 1-12, or shape | molding and bridge | crosslinking.   The composition for positive electrode formation formed by containing the electrolyte composition for secondary batteries in any one of Claims 1-12, a positive electrode active material, and an electroconductivity imparting agent. The composition for positive electrode formation according to claim 14, wherein the conductivity-imparting agent is carbon particles having an average particle diameter of 10 to 80 nm. The composition for forming a positive electrode according to claim 14 or 15, wherein the amount of the conductivity imparting agent is 1 to 30 parts by weight with respect to 100 parts by weight of the positive electrode active material.   The ratio between the amount of the positive electrode active material and the amount of the organic compound represented by the general formula (1) in the secondary battery electrolyte composition is such that the amount of the organic compound is 100 parts by weight of the positive electrode active material. It is 5-100 weight part, The composition for positive electrode formation in any one of Claims 14-16.   The ratio of the amount of the positive electrode active material to the amount of the ion conductive polymer in the electrolyte composition for secondary batteries is such that the amount of the positive electrode active material is 10 to 5, with respect to 100 parts by weight of the ion conductive polymer. It is 000 weight part, The composition for positive electrode formation in any one of Claims 14-17.   The positive electrode film formed by shape | molding the composition for positive electrode formation in any one of Claims 14-17.   A secondary battery having the electrolyte film according to claim 13 as a constituent element.   The secondary battery which has the laminated body of the positive electrode film of Claim 19, and the electrolyte film of Claim 13 in a component. The positive electrode current collector on the positive electrode film surface side and the negative electrode current collector on the negative electrode film side with respect to the laminate having a structure in which the positive electrode film is laminated on one side of the electrolyte film according to claim 13 and the negative electrode film is laminated on the other side. A secondary battery formed by arranging each of the above.