JP2011124121A - Electrolyte composition and secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel electrolyte composition presenting a high ion conductivity and involving no risk of liquid leakage (gelled (solidified) at room temperature), and to provide a highly durable secondary battery containing the electrolyte composition. <P>SOLUTION: The electrolyte composition contains ion liquid expressed by general formula (1) Z<SP>+</SP>N<SP>-</SP>(SO<SB>2</SB>F)(X<SP>1</SP>-R<SP>F1</SP>), and further contains an electrolyte salt and inorganic fine particles. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrolyte composition and a secondary battery.

  An electrolyte used in an electrochemical battery such as a non-aqueous secondary battery is a medium that includes ions according to the purpose and has a function of transporting the ions between electrodes (referred to as ion conduction). For example, a lithium ion secondary battery, which is a typical non-aqueous secondary battery, refers to a medium having a function of transporting lithium ions between electrodes.

  In a secondary battery, a solution-based electrolyte with high ion conductivity is generally used, but the solution-based electrolyte is depleted due to the high volatility of the solvent when incorporated in the battery, There is a problem that leakage due to fluidity reduces the durability of the battery. Further, in order to seal the solution, a metal container must be used, the battery mass becomes heavy, and it is difficult to give the battery shape flexibility.

  It has also been proposed to use an ionic liquid (also referred to as a room temperature molten salt) as a solvent for a solution-based electrolyte, but it has a high ionic conductivity and a low vapor pressure so that it does not volatilize substantially, but it is liquid. The problem of leakage was left.

  Therefore, a method is known in which inorganic fine particles are mixed into an ionic liquid to thicken or gel the liquid (see, for example, Patent Documents 1 and 2), but the ionic conductivity is low, and the electrolyte is still not suitable. It was insufficient. Further, since the viscosity variation due to temperature variation was insufficient, it was difficult to produce by coating.

  On the other hand, it is known that an ionic liquid composed of either a perfluoroalkylsulfonyl group or a perfluoroalkylcarbonyl group and an amide anion containing a fluorosulfonyl group and an organic onium salt exhibits high electrical conductivity. (For example, refer to Patent Document 3) When used as an electrolyte of a non-aqueous secondary battery, there is not only a problem of leakage due to having fluidity, but also a problem of a significant decrease in capacity after repeated charge and discharge. there were.

JP 2003-257476 A JP 2006-310071 A JP 2005-200399 A

  An object of the present invention is to provide a novel electrolyte composition that exhibits high ionic conductivity and does not cause liquid leakage (no gelation (solidification) at room temperature), includes the electrolyte composition, and includes repeated characteristics (both repeated discharge characteristics). And a secondary battery excellent in durability.

  The object of the present invention has been achieved by the following constitution.

  1. An electrolyte composition comprising an ionic liquid represented by the following general formula (1), and further containing an electrolyte salt and inorganic fine particles.

General formula (1)
_{^{Z + N - (SO 2 F}} ) (X 1 -R F1)
[In the formula, Z ⁺ represents a quaternary ammonium cation, a quaternary phosphonium cation, a tertiary sulfonium cation, X ¹ represents —SO ₂ — or —CO—, and R ^F1 represents a perfluoroalkyl having 1 to 4 carbon atoms. Represents a group. ]
2. 2. The electrolyte composition according to 1 above, wherein the Z ⁺ is represented by the following general formula (2) or (3).

[Wherein, R ^{1 to} R ⁴ each represents an alkyl group, and any two groups of R ^{1 to} R ⁴ may form a ring together with the nitrogen atom. ]

[Wherein R ¹¹ and R ¹³ each represents an alkyl group, and R ¹² , R ¹⁴ and R ¹⁵ each represent a hydrogen atom, a halogen atom, an alkyl group, a halogenated alkyl group or an aryl group. ]
3. 3. The electrolyte composition as described in 1 or 2 above, wherein the inorganic fine particles are inorganic oxides.

  4). 4. The electrolyte composition according to any one of items 1 to 3, wherein the inorganic fine particles are mesoporous inorganic fine particles.

  5. 5. The electrolyte composition according to any one of 1 to 4, wherein the inorganic fine particles are inorganic fine particles containing two or more kinds of metals.

  6). A secondary battery comprising the electrolyte composition according to any one of 1 to 5 above.

  According to the present invention, there is provided a novel electrolyte composition that exhibits high ionic conductivity and does not cause liquid leakage (no gelation (solidification) at room temperature), and includes the electrolyte composition, and includes repeated characteristics (also referred to as repeated discharge characteristics). In addition, a secondary battery excellent in durability could be provided.

  Furthermore, the electrolyte composition of the present invention has the property of lowering the viscosity when heated and gelling (solidifying) when the temperature is lowered, and can maintain the shape as a solid electrolyte, so that it can be produced by melt coating on the electrode. Secondary battery can be provided.

  The electrolyte composition of the present invention is a novel electrolyte composition that exhibits high ionic conductivity due to the constitution described in any one of claims 1 to 5 and does not cause liquid leakage (no gelation (solidification) at room temperature). I was able to get things.

  Moreover, the structure described in claim 6 can provide a secondary battery excellent in repetitive characteristics (also referred to as repetitive discharge characteristics) and durability.

  Hereinafter, the present invention, its components, and embodiments for carrying out the present invention will be described in detail.

<Electrolyte composition>
The electrolyte composition of the present invention is an electrolyte composition characterized by containing an ionic liquid represented by the general formula (1), and further containing an electrolyte salt and inorganic fine particles.

<Ionic liquid>
The ionic liquid represented by the general formula (1) will be described.

  The ionic liquid represented by the general formula (1) according to the present invention is a room temperature molten salt compound, and can often be used as an electrolyte with little use of a solvent, and can often be used alone as an electrolyte.

In the general formula (1), examples of the quaternary ammonium cation represented by Z ⁺ include quaternary ammonium cations including aliphatic, alicyclic, aromatic, and heterocyclic rings. Typically, imidazolium, pyridinium, Examples include piperidinium, thiazolium, pyrrolium, pyrazolium, benzimidazolium, indolium, carbazolium, quinolinium, pyrrolidinium, piperazinium, and alkylammonium.

In the general formula (1), examples of the quaternary phosphonium cation represented by Z ⁺ include aliphatic, alicyclic, aromatic and heterocyclic quaternary phosphonium cations.

In the general formula (1), examples of the tertiary sulfonium cation represented by Z ⁺ include aliphatic, alicyclic, aromatic, and heterocyclic tertiary sulfonium cations.

Among the quaternary ammonium cations, quaternary phosphonium cations, and tertiary sulfonium cations represented by Z ⁺ in the general formula (1), alkylammonium cations and imidazolium cations are preferred. Specifically, Z ⁺ is the above general formula. An alkylammonium cation represented by the formula (2) or an imidazolium cation represented by the general formula (3) is preferable.

(Alkylammonium cation represented by the general formula (2))
The alkyl ammonium cation represented by the general formula (2) will be described.

In the general formula (2), R ^{1 to} R ⁴ are alkyl groups (for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, pentyl group, hexyl group, octyl group). Or a cycloalkyl group (for example, a cyclopentyl group, a cyclohexyl group, etc.).

In general formula (2), alkyl groups are preferred as R ^{1 to} R ⁴ .

In the general formula (2), the group represented by R ^{1 to} R ⁴ may further have a substituent, for example, an alkyl group, a cycloalkyl group, an aryl group (for example, a phenyl group, a naphthyl group). A heterocyclic group (for example, furyl group, thienyl group, pyridyl group, pyridazyl group, pyrimidyl group, pyrazyl group, triazyl group, imidazolyl group, pyrazolyl group, thiazolyl group, benzoimidazolyl group, benzoxazolyl group, quinazolyl group, phthalazyl group) Group, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.) alkenyl group (for example, ethylene group, propylene group, butylene group, etc.), alkoxy group (for example, methoxy group, ethoxy group, propyloxy group, pentyloxy group) Hexyloxy group, octyloxy group, dodecyloxy group), cycloal Xy group (for example, cyclopentyloxy group, cyclohexyloxy group), aryloxy group (for example, phenoxy group, naphthyloxy group), alkylthio group (for example, methylthio group, ethylthio group, propylthio group), cycloalkylthio group (for example, cyclopentyl group) Thio group, cyclohexylthio group), arylthio group (for example, phenylthio group, naphthylthio group), alkoxycarbonyl group (for example, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group), aryloxycarbonyl group (for example, phenyl) Oxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, Xylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl) Group, cyclohexylcarbonyl group, octylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, phenylcarbonyloxy) Group), acylamino group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonyl group) Mino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, trifluoromethylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group), sulfonylamino group (for example, methyl) Sulfonylamino group, ethylsulfonylamino group, hexylsulfonylamino group, phenylsulfonylamino group), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexyl) Aminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, phenylaminocarbonyl group, naphthylamino Sulfonyl group, 2-pyridylaminocarbonyl group), ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group), sulfinyl group (for example, Methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group), alkylsulfonyl group (for example, methylsulfonyl Group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group), arylsulfonyl group (for example, phenylsulfonyl group, naphthylsulfonyl group) Group, 2-pyridylsulfonyl group), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, anilino group, naphthylamino group, 2-pyridylamino group), cyano group, nitro group Group, halogen atom (fluorine, chlorine, bromine, iodine, etc.), halogenated alkyl group (for example, methyl fluoride group, trifluoromethyl group, chloromethyl group, trichloromethyl group, perfluoropropyl group) and the like. .

  Among the above substituents, preferably an alkenyl group, aryl group, alkoxy group, alkoxycarbonyl group, acyl group, acyloxy group, acylamino group, carbamoyl group, sulfamoyl group, amino group, cyano group, halogenated alkyl group, halogen atom Etc.

In General Formula (2), any two groups out of R ^{1 to} R ⁴ may form a ring together with the nitrogen atom.

<< Imidazolium cation represented by general formula (3) >>
The imidazolium cation represented by the general formula (3) according to the present invention will be described.

In General formula (3), R < ¹¹ >, R < ¹³ > represents an alkyl group, Specifically, the group similar to the group quoted by R < ¹ > -R < ⁴ > is mentioned.

In the general formula ^(3), examples of the substituent represented by ^{R 12, R 14, R 15} , in the general formula (2) include the same groups ^as the groups listed R 1 to R ^4.

  Preferred examples of the substituent include a halogen atom, an alkyl group, a halogenated alkyl group, and an aryl group, and a hydrogen atom is more preferred.

Next, in the general formula _{^{(1), N - (SO}} 2 F) (X 1 -R F1) anion represented by will be described.

In the general formula (1), X ¹ represents —SO ₂ — or —CO—.

In the general formula (1), R ^F1 represents a perfluoroalkyl group having 1 to 4 carbon atoms, and is, for example, a trifluoromethyl group, a pentafluoroethyl group, a heptafluoropropyl group, or a nonafluorobutyl group.

R ^F1 may further have a substituent, and examples thereof include a perfluoroalkyloxy group (for example, —OCF ₃ , —OC ₂ F ₅ , —OC ₃ F ₇ ), a halogen atom, and a cyano group. Is preferably a perfluoroalkyloxy group, and the total number of carbon atoms contained in R ^F1 is 4 or less.

Among the perfluoroalkyl groups having 1 to 4 carbon atoms represented by R ^F1 in the general formula (1), an unsubstituted perfluoroalkyl group is preferable, and a trifluoromethyl group is more preferable. .

  Although the concrete of the cation used for formation of the ionic liquid represented with General formula (1) below is shown, this invention is not limited to these.

(Specific example of cation represented by Z ⁺ )

  Hereinafter, although the specific example of the anion used for formation of the ionic liquid represented by the said General formula (1) is shown in Table 1, this invention is not limited to these.

_{^{(N - (SO 2 F)}} ( Specific examples of the anion represented by X 1 ^{-R F1))}

  Subsequently, although the specific example of the ionic liquid represented by General formula (1) is shown in Table 2, this invention is not limited to these.

  The ionic liquid according to the present invention is preferably a liquid around room temperature (25 ° C.). The melting point of these compounds is preferably 80 ° C. or lower, more preferably 60 ° C. or lower, and further preferably 30 ° C. or lower.

The ionic liquid represented by the general formula (1) can be obtained by a method described in JP-A-2005-200309, JP-A-2007-182410, or the like according to a conventionally known quaternary ammonium cation, quaternary phosphonium cation, tertiary. halides sulfonium cation, hydroxide, toluenesulfonate, etc., and in general formula (1) _{^{N - (SO 2 F) (}} X 1 -R F1) anion potassium salt of which is represented by the structure of the sodium salt and lithium A salt can be synthesized as a raw material.

  The electrolyte composition of the present invention contains at least one ionic liquid, but may be used in combination of two or more.

  The blending amount of the ionic liquid in the electrolyte composition is preferably 10% by mass to 90% by mass, and particularly preferably 30% by mass to 80% by mass.

  Although the synthesis example of the ionic liquid represented by General formula (1) is shown below, this invention is not limited to these.

<< Synthesis Example 1: Synthesis of IL-16 >>
IL-16 was synthesized through the following steps 1-1 and 1-2.

Step 1-1: Synthesis of (fluorosulfonyl) (trifluoroacetyl) imide potassium salt 50 g (0.44 mol) of trifluoroacetylamide (Tokyo Chemical Industry T0598) was dissolved in 250 ml of dehydrated methanol, and t-butoxy was dissolved in this solution. A solution in which 35.4 g (0.44 mol) of lithium was dissolved in 140 ml of dehydrated methanol was dropped, and the mixture was reacted at 50 ° C. for 2 hours with stirring.

  After completion of the reaction, the solvent was distilled off under reduced pressure to obtain a potassium salt of trifluoroacetylamide. Next, the total amount of the obtained potassium salt was dissolved in 1000 ml of dehydrated diethyl ether, and the liquid was cooled to −20 ° C. and then disulfuryl fluoride (synthesized according to Inorganic Synthesis vol. 8, p. 151) 80.6 g (0. 44 mmol) dissolved in 120 ml of dehydrated ether was added and reacted at −20 ° C. for 8 hours.

  After completion of the reaction, the liquid temperature was returned to room temperature, and after filtration, the solid content was washed with ether and dried under reduced pressure to obtain 63.0 g of (fluorosulfonyl) (trifluoromethanesulfonyl) imide potassium salt (yield 71%). The product was confirmed by IR spectrum.

Step 1-2: Synthesis of IL-16 10 g (74 mmol) of N-methyl-N- (n-propyl) pyrrolidinium chloride was dissolved in 50 ml of deionized water, and obtained in Synthesis Example (1-1) ( 17.3 g (74 mmol) of fluorosulfonyl) (trifluoroacetyl) imide potassium salt was added. After stirring for 1 hour at room temperature, the product was extracted with 50 ml of dichloromethane and washed 5 times with 50 ml of deionized water. Dichloromethane was distilled off under reduced pressure to obtain the target IL-16 (20.0 g; yield 78%).

<< Synthesis Example 2: Synthesis of IL-21
IL-21 was synthesized through the following steps 2-1, 2-2, 2-3.

Step 2-1: Synthesis of N-methyl-N- (methoxyethyl) pyrrolidinium bromide 10 g (0.12 mol) of N-methylimidazole was dissolved in 50 ml of acetone, and 16.3 g (0 .12 mol) was added dropwise over 10 minutes.

  After completion of the dropwise addition, the mixture was returned to room temperature and stirred for 1 hour, and the precipitated solid was filtered and dried to obtain 19.8 g of N-methyl-N- (methoxyethyl) pyrrolidinium bromide (yield 75%).

Step 2-2: Synthesis of (fluorosulfonyl) (trifluoromethanesulfonyl) imide potassium salt 50 g (0.267 mol) of potassium salt of trifluoromethanesulfonamide (EF-A12 manufactured by Mitsubishi Materials) was dissolved in 800 ml of dehydrated diethyl ether, After cooling to −20 ° C., a solution in which 48.7 g (0.267 mmol) of disulfuryl fluoride; (FSO 2) 2 O (synthesized according to Inorganic Synthesis vol. 8, p. 151) was dissolved in 80 ml of dehydrated ether was added. , Reacted at −20 ° C. for 8 hours.

  After completion of the reaction, the liquid temperature was returned to room temperature, and after filtration, the solid content was washed with ether and dried under reduced pressure to obtain 50.0 g of (fluorosulfonyl) (trifluoromethanesulfonyl) imide potassium salt (yield 70%). The product was confirmed by IR spectrum.

Step 2-3: Synthesis of IL-21 10 g (45 mmol) of N-methyl-N- (methoxyethyl) pyrrolidinium bromide was dissolved in 50 ml of deionized water, and obtained in Synthesis Example (2-2) ( 12 g (45 mmol) of fluorosulfonyl) (trifluoromethanesulfonyl) imide potassium salt was added. After stirring for 1 hour at room temperature, the product was extracted with 50 ml of dichloromethane and washed 5 times with 50 ml of deionized water. Dichloromethane was distilled off under reduced pressure to obtain the target compound IL-21 (15.0 g; yield 79%).

<< Synthesis Example 3: Synthesis of IL-35 >>
8.0 g (55 mmol) of 1-ethyl-3-methylimidazolium chloride was dissolved in 40 ml of deionized water, and (fluorosulfonyl) (trifluoromethanesulfonyl) imide potassium salt obtained in Step 2-2 was added thereto. 7 (55 mmol) was added.

  After stirring for 1 hour at room temperature, the product was extracted with 40 ml of dichloromethane and washed 5 times with 40 ml of deionized water.

  Dichloromethane was distilled off under reduced pressure to obtain the target IL-35 (15.0 g; yield 81%).

《Electrolyte salt》
The electrolyte salt according to the present invention will be described.

  Examples of the electrolyte salt of the present invention include salts of metal ions belonging to Group 1 or Group 2 of the periodic table. Among them, salts of metal ions belonging to Group 1 of the periodic table are preferable, and belong to Group 1 of the periodic table. As metal ions, lithium, sodium, and potassium ions are preferred.

As anions of metal ion salts, halide ions (I ⁻ , Cl ⁻ , Br ⁻ etc.), SCN ⁻ , BF ₄ ⁻ , BF ₃ (CF ₃ ) ⁻ , BF ₃ (C ₂ F ₅ ) ⁻ , PF _{^{6 -, ClO 4 -, SbF}} 6 -, (FSO 2) 2 N -, (CF 3 SO 2) 2 N -, (C 2 F 5 SO 2) 2 N -, Ph 4 B -, (C 2 H ^{_{4 O 2) 2 B -,}} (CF 3 SO 2) 3 C -, CF 3 COO -, CF 3 SO 2 O -, C 6 F 5 SO 2 O - , and the like.

Examples of anions include SCN ⁻ , BF ₄ ⁻ , BF ₃ (CF ₃ ) ⁻ , BF ₃ (C ₂ F ₅ ) ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , SbF ₆ ⁻ , (CF ₃ SO ₂ ) ₂ N ^−. , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , and CF ₃ SO ₂ O ⁻ are preferable.

Typical electrolyte salts include LiOSO ₂ CF ₃ , LiPF ₆ , LiClO ₄ , LiI, LiBF ₄ , LiBF ₃ (CF ₃ ), LiBF ₃ (C ₂ F ₅ ), LiCF ₃ COO, LiSCN, LiN (SO _{2 CF 3) 2, LiN (SO} 2 F) 2, NaI, NaOSO 2 CF 3, NaClO 4, NaBF 4, NaAsF 6, KOSO 2 CF 3, KSCN, KPF 6, KClO 4, KAsF 6, and the like.

  More preferred is the above Li salt.

  Examples of the electrolyte salt according to the electrolyte composition of the present invention include International Publication No. 95/18456 pamphlet or J.P. Phys. Chem. B, 103, 4164 (1999) or the like may be added.

《Inorganic fine particles (also referred to simply as inorganic particles)》
The inorganic fine particles (also referred to as inorganic particles) according to the present invention will be described.

  As the inorganic fine particles according to the present invention, any material can be used as long as it is a substance inactive with respect to the ionic liquid and the electrolyte salt.

  The inorganic fine particles according to the present invention are preferably inorganic oxides, and the metals constituting the inorganic oxide particles include Li, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Y, Nb, Zr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, La, Ta, Hf, W, Ir, Tl, Pb, Selected from the group consisting of Bi and rare earth metals.

  Specifically, for example, silicon oxide, titanium oxide, zinc oxide, aluminum oxide, zirconium oxide, hafnium oxide, niobium oxide, tantalum oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, indium oxide, tin oxide, oxide Inorganic oxide fine particles composed of lead and the like can be mentioned.

  In addition, rare earth oxides can also be used as the oxide fine particles used in the present invention, specifically, scandium oxide, yttrium oxide, lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, Fine particles containing gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, and the like can be given.

  Among these, neutral or acidic metal inorganic oxide fine particles are effective in terms of improving ion conductivity. Examples thereof include iron oxide, zirconium oxide, clay, tin oxide, tungsten oxide, titanium oxide, aluminum phosphate, silicon oxide, zinc oxide, and aluminum oxide.

  The hydroxyl group on the surface of the inorganic oxide interacts with the ion conductive compound or the salt of the secondary battery to form an ion path that transports ions at a high speed.

  The shape of the inorganic oxide may be spherical, but may be preferably used even if it is a mesoporous, flat or needle-like particle.

<< Mesoporous inorganic fine particles (also called MP particles) >>
The mesoporous inorganic fine particle which is an example of a preferable embodiment of the inorganic fine particle according to the present invention will be described.

  The mesoporous inorganic fine particles are porous inorganic particles having a plurality of pores having a pore diameter of 2 nm to 50 nm (hereinafter abbreviated as mesopores), which is a region to which Kelvin's capillary condensation theory can be applied.

  The pore diameter and pore distribution can be measured by a mercury intrusion method, a gas adsorption method, or the like. The pore diameter of the present invention refers to the median diameter of the pore distribution calculated by analyzing the hysteresis pattern of the adsorption / desorption isotherm obtained by the gas adsorption method using a pore distribution measuring device.

The composition of the mesoporous inorganic fine particles is not particularly limited as long as it has mesopores, but mesoporous inorganic fine particles having metal oxide as a skeleton and regularly arranged mesopores are preferable. As the metal oxide, SiO ₂ , Al ₂ O ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , TiO ₂ , ZrO ₂ , SnO ₂ or a composite oxide thereof can be preferably used.

  As a method for producing mesoporous inorganic fine particles, a conventionally known method such as hydrothermal synthesis using a surfactant or an organic compound as a template can be used, for example, a method described in JP-A-2005-53737. It is done. The mesoporous inorganic fine particles can hold a solvent inside the mesopores or on the surface of the porous body.

The mesoporous inorganic particles according to the present invention, particularly those specific surface area of 300m ² / g~1000m ² / g, safety, preferred from the viewpoint of charge and discharge durability.

  The specific surface area of the mesoporous inorganic fine particles according to the present invention is calculated from the adsorption isotherm obtained by adsorbing nitrogen gas or the like to the particle powder using a specific surface area meter and calculated as the BET specific surface area using the BET isotherm adsorption equation. Say.

  The content of the mesoporous inorganic fine particles in the electrolyte composition is preferably in the range of 5% by mass to 40% by mass with respect to the ionic liquid from the viewpoint of safety and voltage characteristics.

  The average particle diameter of the mesoporous inorganic fine particles is preferably 1 μm to 50 μm, more preferably 5 μm to 20 μm, from the viewpoint of safety and voltage characteristics.

  The average particle diameter is a volume average value of the diameter (sphere converted particle diameter) when each particle is converted into a sphere having the same volume, and this value can be evaluated from an electron micrograph.

  That is, it is obtained by taking a transmission electron micrograph of the electrolyte composition or particle powder, measuring 200 or more particles in a certain visual field range, obtaining a sphere equivalent particle diameter of each particle, and obtaining an average value thereof. Value.

  Furthermore, the mesoporous inorganic fine particles according to the present invention are preferably subjected to surface hydrophobization treatment from the viewpoint of uniform mixing with the ionic liquid.

  Moreover, the inorganic fine particles according to the present invention may be uniformly mixed with two or more kinds of inorganic oxides, or may be separated inside like a core-shell type.

  Examples of such inorganic oxides include Group 4 elements of the periodic table such as magnesium, silicon, zirconium, and titanium, and two or more of these inorganic oxides are combined.

  For example, a composite particle of an inorganic oxide having a high ion conductivity improving effect and an inorganic oxide having a good compatibility with the dispersant can have both an ion conductivity improving effect and a dispersibility.

  For these particles, a flame method or a plasma method using a plurality of alkoxides or chlorides can be used.

  Moreover, it can also granulate in a liquid using catalysts, such as ammonia.

  Furthermore, the surface of these inorganic compounds can be surface-treated by using a silane coupling agent or a dispersant. Depending on the degree of surface treatment, the surface can be classified into hydrophilic and hydrophobic, but can be used in either case.

  The inorganic fine particles according to the present invention preferably contain silica, and the silica content is preferably 10% to 90%, more preferably 15% to 85%.

  The inorganic fine particles according to the present invention preferably have a hydrophobic surface.

  As the hydrophobizing agent, hexamethyldisilazane, trimethylmethoxysilane, trimethylethoxysilane, trimethylsilyl chloride and the like can be preferably used.

  As the surface treatment method, there are a dry method in which the powder is directly sprayed to heat and fixed, and a wet method in which particles are dispersed in a solution and a surface treatment agent is added to carry out the surface treatment. A wet method in which is dispersed is desirable. For example, particles treated by a wet method using a technique as described in JP-A-2007-264582 have high dispersibility and can be preferably used.

  The particle size of the inorganic fine particles according to the present invention is desirably 100 nm or less, and more desirably 20 nm or less. In the case of fine particles having a particle diameter of 100 nm or more, the ionic liquid may not be gelled with sufficient strength.

  The content of the inorganic fine particles according to the present invention is not particularly limited, but is preferably 5 parts by mass or more and 100 parts by mass or less, and more preferably 10 parts by mass or more and 70 parts by mass or less with respect to 100 parts by mass of the ionic liquid. .

  In the present invention, the solvent can be used up to 50% by mass in combination with the above electrolyte constituent elements. However, from the viewpoint of storage stability, it is more preferable not to use a solvent.

<< Polymerizable compound (simply also referred to as monomer) >>
The polymerizable compound (monomer) used in the present invention will be described.

  The electrolyte of the present invention can contain a polymerizable compound in order to improve applicability.

  The polymerizable compound is a compound having at least one acryloyl group, methacryloyl group, vinyl group, styryl group, epoxy group, oxetane group or the like as a polymerizable group in the molecule, and two or more in the polymerizable compound When the compound has a polymerizable group, a three-dimensional network structure is formed by the reaction of this compound, which can further enhance the shape retention ability of the electrolyte, which is preferable.

  Here, the compound having a polymerizable group in the molecule is not particularly limited. For example, glycidyl methacrylate, glycidyl acrylate, methoxydiethylene glycol methacrylate, methoxytriethylene glycol methacrylate, methoxypolyethylene glycol methacrylate (average A compound having one acrylic acid group or methacrylic acid group in the molecule such as acrylic acid or methacrylic acid ester having a molecular weight of 200 to 1200), methacryloyl isocyanate, 2-hydroxymethyl methacrylic acid, N, N-dimethylaminoethyl methacrylic acid, etc. Is mentioned.

  Also, for example, divinylbenzene, divinylsulfone, aryl methacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate (average molecular weight 200 to 1000), dimethacrylic acid 1, 3-butylene glycol, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate (average molecular weight 400), 2-hydroxy-1,3-dimethacryloxypropane, 2,2- Bis- [4- (methacryloxyethoxy) phenyl] propane, 2,2-bis- [4- (methacryloxyethoxy diethoxy) phenyl] propane, 2,2-bis- [4- (methacryloxyethoxy) Polyethoxy) phenyl] propane, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate (average molecular weight 200-1000), 1,3-butylene glycol diacrylate, 1,6-hexanediol diacrylate , Neopentyl glycol diacrylate, polypropylene glycol diacrylate (average molecular weight 400), 2-hydroxy-1,3-diaacryloxypropane, 2,2-bis- [4- (acryloxyethoxy) phenyl] propane, 2, 2-bis- [4- (acryloxyethoxy diethoxy) phenyl] propane, 2,2-bis- [4- (acryloxyethoxy polyethoxy) phenyl] propane, trimethylol proppant Acrylate, trimethylolpropane trimethacrylate, tetramethylolmethane triacrylate, tetramethylolmethane tetraacrylate, tricyclodecane dimethanol acrylate, hydrogenated dicyclopentadiene diacrylate, polyester diacrylate, polyester dimethacrylate, etc. A compound having two or more double bonds is preferably used.

  Among the compounds containing a polymerizable double bond, particularly preferred polymerizable monomers include diester compounds containing a polyoxyalkylene component represented by the following general formula (4), and this and the following general formula (5): It is preferable to use in combination a monoester compound containing a polyoxyalkylene component represented by the formula (1) and a triester compound.

In formula, R < ⁶ > -R < ⁸ > is a hydrogen atom or a methyl group, an ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, etc. Is an alkyl group having 1 to 6 carbon atoms, particularly 1 to 4 carbon atoms, satisfying the conditions of X ≧ 1 and Y ≧ 0, or satisfying the conditions of X ≧ 0 and Y ≧ 1 R ^{6 to} R ⁸ are a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, an s-butyl group, or a t-butyl group.

However, in formula, R < ⁹ > -R < ¹¹ > is a hydrogen atom or a methyl group, an ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl. Represents an alkyl group having 1 to 6 carbon atoms, particularly 1 to 4 carbon atoms such as a group, and satisfies the conditions of A ≧ 1 and B ≧ 0, or satisfies the conditions of A ≧ 0 and B ≧ 1 R ^{9 to} R ¹¹ are preferably a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, an s-butyl group, or a t-butyl group.

In the general formula (4), for example, (M-1) in which X = 9, Y = 0, R ⁶ = R ⁸ = CH ₃ is preferably used.

On the other hand, in the general formula (5), for example, (M-2) in which A = 2 or 9, B = 0, and R ⁹ = R ¹¹ = CH ₃ is preferably used.

  As the triester compound, trimethylolpropane trimethacrylate is suitable.

  The polymerizable compound is polymerized by irradiation with actinic rays or heat in a mixture with the ionic liquid and cured to form a lithium ion conductive cured film.

  In the present invention, it is preferable to polymerize and cure by irradiation with actinic rays from the viewpoint of handleability and productivity.

  Moreover, it is also preferable to heat after actinic ray irradiation in order to accelerate hardening.

The actinic rays are usually carried out by light, ultraviolet rays, electron beams, X-rays, etc. Among them, ultraviolet rays are preferable. A chemical lamp or the like is used. Although the dose is not particularly limited, but is preferably ^{100mJ / cm 2 ~1000mJ / cm 2} , more preferably from ^{200mJ / cm 2 ~700mJ / cm 2} .

  When polymerizing and curing by irradiation with these actinic rays, the photopolymerization initiator is 0.3 parts by mass or more, preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the polymerizable component of the electrolyte composition. Contain.

  The photopolymerization initiator is not particularly limited, and a known photopolymerization initiator can be used, and examples thereof include benzophenone, P, P′-bis (dimethylamino) benzophenone, P, P′-bis (diethylamino). ) Benzophenone, P, P'-bis (dibutylamino) benzophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin phenyl ether, benzoin isobutyl ether, benzoylbenzoic acid, benzoylbenzoic acid methyl Benzyl diphenyl disulfide, benzyl dimethyl ketal, dibenzyl, diacetyl, anthraquinone, naphthoquinone, 3,3'-dimethyl-4-methoxybenzophenone, dichloroacetophenone, 2 Chlorothioxanthone, 2-methylthioxanthone, 2,4-diethylthioxanthone, 2,2-diethoxyacetophenone, 2,2-dichloro-4-phenoxyacetophenone, phenylglyoxylate, α-hydroxyisobutylphenone, dibenzoparone, 1- (4-Isopropylphenyl) -2-hydroxy-2-methyl-1-propanone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propanone, tribromophenylsulfone, tribromomethylphenylsulfone Methylbenzoylformate, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-dimethoxy-1,2-diphenylmethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and Are 2, 4, 6- [tris (trichloromethyl)]-1,3,5-triazine, 2,4- [bis (trichloromethyl)]-6- (4'-methoxyphenyl) -1,3,5-triazine, 2, 4- [bis (trichloromethyl)]-6- (4'-methoxynaphthyl) -1,3,5-triazine, 2,4- [bis (trichloromethyl)]-6- (piperonyl) -1,3 5-triazine, 2,4- [bis (trichloromethyl)]-6- (4'-methoxystyryl) -1,3,5-triazine and other triazine derivatives, acridine and 9-phenylacridine and other acridine derivatives, , 2'-bis (o-chlorophenyl) -4,5,4 ', 5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis (o-chlorophenyl) -4,5,4' , 5'-Tetra Phenyl-1,1'-biimidazole, 2,2'-bis (o-fluorophenyl) -4,5,4 ', 5'-tetraphenyl-1,1'-biimidazole, 2,2'-bis (O-methoxyphenyl) -4,5,4 ', 5'-tetraphenyl-1,1'-biimidazole, 2,2'-bis (p-methoxyphenyl) -4,5,4', 5 ' -Tetraphenyl-1,1'-biimidazole, 2,4,2 ', 4'-bis [bi (p-methoxyphenyl)]-5,5'-diphenyl-1,1'-biimidazole, 2, 2'-bis (2,4-dimethoxyphenyl) -4,5,4 ', 5'-diphenyl-1,1'-biimidazole, 2,2'-bis (p-methylthiophenyl) -4,5 4 ', 5'-diphenyl-1,1'-biimidazole, bis (2,4,5 Triphenyl) -1,1′-biimidazole and the like, and tautomerism covalently bonded at 1,2′-, 1,4′-, 2,4′-disclosed in Japanese Examined Patent Publication No. 45-37377 Hexaarylbiimidazole derivatives, triphenylphosphine, 2-benzoyl-2-dimethylamino-1- [4-morpholinophenyl] -butane, and the like, especially in terms of handling. Particularly preferred are 2-methyl-1-phenylpropan-1-one, 2,2-dimethoxy-1,2-diphenylmethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and the like.

  Moreover, when making it superpose | polymerize and harden | cure with a heat | fever, 0.1 mass part-5 mass parts with respect to 100 mass parts of polymeric components of an electrolyte composition, especially 0.3 mass part-1 are used. It is preferable to contain a mass part.

  The thermal polymerization initiator is not particularly limited. For example, AIBN (azobisisobutyronitrile), benzoyl peroxide, lauroyl peroxide, ethyl methyl ketone peroxide, bis- (4-t-butylcyclohexyl) peroxy Examples include peroxydicarbonates such as dicarbonate and diisopropyl peroxydicarbonate. Moreover, when it superposes | polymerizes and hardens using light and a heat together, it is preferable to use said photoinitiator and said thermal polymerization initiator together.

<< Solvent (also called solvent) >>
In the present invention, up to 50% by mass of the solvent can be used together with the constituent elements of the electrolyte composition. However, from the viewpoint of storage stability, it is more preferable not to use a solvent.

  The solvent used for the preparation of the electrolyte composition of the present invention is a compound that has a low viscosity and improved ion mobility, or has a high dielectric constant and improved effective carrier concentration, and can exhibit excellent ion conductivity. It is desirable that

  Examples of such solvents include carbonate compounds such as ethylene carbonate and propylene carbonate, heterocyclic compounds such as 3-methyl-2-oxazolidinone, ether compounds such as dioxane and diethyl ether, ethylene glycol dialkyl ether, propylene glycol dialkyl ether, and polyethylene. Chain ethers such as glycol dialkyl ether and polypropylene glycol dialkyl ether, nitrile compounds such as acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, and benzonitrile, esters such as carboxylic acid ester, phosphoric acid ester and phosphonic acid ester And aprotic polar substances such as dimethyl sulfoxide and sulfolane.

  Among these, carbonate compounds such as ethylene carbonate and propylene carbonate, heterocyclic compounds such as 3-methyl-2-oxazolidinone, nitrile compounds such as acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, and benzonitrile, and esters are particularly preferred. preferable. These may be used alone or in combination of two or more.

  The solvent preferably has a boiling point of 200 ° C. or higher, more preferably 250 ° C. or higher, more preferably 270 ° C. or higher, from the viewpoint of improving durability due to volatility.

《Other additives》
The electrolyte composition of the present invention may be used after adding a polymer, an oil gelling agent or the like. In the case of adding a polymer, compounds described in “Polymer Electrolyte Reviews-1 and 2” (J.R. MacCallum and CA Vincent co-edit, ELSEVIER APPLIED SCIENCE) can be used. Acrylonitrile and polyvinylidene fluoride can be preferably used.

  When adding an oil gelling agent, it is recommended that ChemSoc. Japan, Ind. Chem. Sec. 46, 779 (1943), J. Am. Am. Chem. Soc. 111, 5542 (1989), J. Am. Chem. Soc. , Chem. Commun. 1993, 390, Angew. Chem. Int. Ed. Engl. , 35, 1949 (1996), Chem. Lett. 1996, 885, J. et al. Chm. Soc. , Chem. Commun. , 1997, 545 can be used, but preferred compounds are those having an amide structure in the molecular structure.

<Secondary battery>
The secondary battery of the present invention will be described.

《Positive electrode active material》
Examples of the positive electrode active material include an inorganic active material, an organic active material, and a composite thereof. However, the energy density of an inorganic active material or a composite of an inorganic active material and an organic active material is particularly large. It is preferable from the point.

As the inorganic active material, for example, Li _0.3 MnO ₂ , Li ₄ Mn ₅ O ₁₂ , V ₂ O ₅ , LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiFePO ₄ LiCo _1/3 Ni _1/3 Mn _{1 / 3} O ₂ , Li _1.2 (Fe _0.5 Mn _0.5 ) _0.8 O ₂ , Li _1.2 (Fe _0.4 Mn _0.4 Ti _0.2 ) _0.8 O ₂ , Li _{1 + x} (Ni _0.5 Mn _0.5 ) _1-x O ₂ , LiNi _0.5 Mn _1.5 O ₄ , Li ₂ MnO ₃ , Li _0.76 Mn _0.5 1Ti _0.49 O ₂ , LiNi _{0 .8} Co _0.15 Al _0.05 O ₂ , Fe ₂ O ₃ , and other metal oxides, LiFePO ₄ , LiCoPO ₄ , LiMnPO ₄ , Li ₂ MPO ₄ F (M = Fe, Mn), LiMn _0.875 Fe _{0. 25 PO 4, Li 2 FeSiO 4} , Li 2-x MSi 1-x P x O 4 (M = Fe, Mn), LiMBO 3 (M = Fe, Mn) phosphoric acids such as silicic acid, like boric acid system It is done. In these chemical formulas, x is preferably in the range of 0-1.

Further, fluorine-based compounds such as FeF ₃ , Li ₃ FeF ₆ , and Li ₂ TiF ₆ , metal sulfides such as Li ₂ FeS ₂ , TiS ₂ , MoS ₂ , and FeS, and composite oxides of these compounds and lithium can be given. Examples of organic active materials include conductive polymers such as polyacetylene, polyaniline, polypyrrole, polythiophene, and polyparaphenylene, organic disulfide compounds, and organic sulfur compounds DMcT (2,5-dimercapto-1,3,4-thiadiazole). ), Benzoquinone compounds PDBM (poly 2,5-dihydroxy-1,4-benzoquinone-3,6-methylene), carbon disulfides, sulfur-based positive electrode materials such as active sulfur, organic radical compounds, and the like.

  Moreover, it is preferable that the surface of the positive electrode active material is coated with an inorganic oxide from the viewpoint of extending the life of the battery. In coating the inorganic oxide, a method of coating the surface of the positive electrode active material is preferable, and examples of the coating method include a method of coating using a surface modifying apparatus such as a hybridizer.

Examples of the inorganic oxide include a periodic table used for the constitution of magnesium oxide, silicon oxide, alumina, zirconia, titanium oxide, barium titanate, calcium titanate, lead titanate, γ-LiAlO ₂ , LiTiO _{3 and the} like. Although oxides of Group 2 to Group 14 elements are mentioned, silicon oxide is particularly preferable.

<Negative electrode active material>
There is no restriction | limiting in particular about a negative electrode, What adhered the negative electrode active material to the electrical power collector can be utilized. Powders such as graphite and tin alloys can be applied as pastes together with binders such as styrene butadiene rubber and polyvinylidene fluoride on the current collector, dried, and press-molded. .

  A silicon-based thin film negative electrode in which a 3-5 micron silicon-based thin film is directly formed on a current collector by physical vapor deposition (such as sputtering or vacuum deposition) can also be used. In the case of a lithium metal negative electrode, it is preferable that a lithium foil of 10 μm to 30 μm is attached on a copper foil.

  From the viewpoint of increasing the capacity, it is preferable to be composed of a silicon-based thin film negative electrode or a lithium metal negative electrode.

<Electrode mixture>
Examples of the electrode mixture used in the present invention include those to which a lithium salt, an aprotic organic solvent, or the like is added in addition to a conductive agent, a binder, a filler, and the like.

  As the conductive agent, any material may be used as long as it is an electron conductive material that does not cause a chemical change in the constituted secondary battery. Usually, natural graphite (scale-like graphite, scale-like graphite, earth-like graphite, etc.), artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber or metal powder (copper, nickel, aluminum, silver (Japanese Patent Laid-Open No. Sho 63-63)) 148554), etc.), conductive fibers such as metal fibers or polyphenylene derivatives (described in JP-A-59-20971), or a mixture thereof.

  Among them, the combined use of graphite and acetylene black is particularly preferable. As addition amount of the said electrically conductive agent, 1 mass%-50 mass% are preferable, and 2 mass%-30 mass% are more preferable. In the case of carbon or graphite, 2% by mass to 15% by mass is particularly preferable.

  In the present invention, a binder for holding the electrode mixture is used. Examples of such a binder include polysaccharides, thermoplastic resins, and polymers having rubber elasticity. Among them, for example, starch, carboxymethylcellulose, cellulose, diacetylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, Water-soluble polymers such as sodium alginate, polyacrylic acid, sodium polyacrylate, polyvinyl phenol, polyvinyl methyl ether, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylonitrile, polyacrylamide, polyhydroxy (meth) acrylate, styrene-maleic acid copolymer , Polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, vinyl Redene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, polyvinyl acetal resin, methyl methacrylate, 2-ethylhexyl acrylate, etc. ) (Meth) acrylic ester copolymer containing acrylic ester, (meth) acrylic ester-acrylonitrile copolymer, polyvinyl ester copolymer containing vinyl ester such as vinyl acetate, styrene-butadiene copolymer , Acrylonitrile-butadiene copolymer, polybutadiene, neoprene rubber, fluororubber, polyethylene oxide, polyester polyurethane resin, polyether polyurethane resin, polycarbonate DOO polyurethane resins, polyester resins, phenolic resins, emulsion (latex) or a suspension such as an epoxy resin is preferable, a latex of polyacrylate, carboxymethyl cellulose, polytetrafluoroethylene, polyvinylidene fluoride is more preferable.

  The said binder can be used individually by 1 type or in mixture of 2 or more types. When the amount of the binder added is small, the holding power and cohesive force of the electrode mixture are weakened. If the amount is too large, the electrode volume increases and the capacity per electrode unit volume or unit mass decreases. For this reason, the addition amount of the binder is preferably 1% by mass to 30% by mass, and more preferably 2% by mass to 10% by mass.

  As the filler, any fibrous material that does not cause a chemical change in the secondary battery of the present invention can be used. Usually, olefin polymers such as polypropylene and polyethylene, fibers such as glass and carbon are used. Although the addition amount of a filler is not specifically limited, 0-30 mass% is preferable.

"separator"
The secondary battery of the present invention can be used in combination with a separator. The separator used in combination for ensuring safety must have a function of blocking the current by closing the gap at 80 ° C or higher, and blocking the current, and the closing temperature is 90 ° C or higher and 180 ° C or lower. Is preferred.

  The shape of the holes of the separator is usually circular or elliptical, and the size is 0.05 μm to 30 μm, preferably 0.1 μm to 20 μm.

  Furthermore, it may be a rod-like or irregular-shaped hole as in the case of making by a stretching method or a phase separation method. The ratio of these gaps, that is, the porosity, is preferably in the range of 20% to 90%, and more preferably in the range of 35% to 80%.

  The separator may be a single material such as polyethylene or polypropylene, or two or more composite materials. What laminated | stacked 2 or more types of microporous film which changed the hole diameter, the porosity, the obstruction | occlusion temperature of a hole, etc. is preferable.

<Current collector>
As the positive / negative current collector, an electron conductor that does not cause a chemical change in the secondary battery of the present invention is used. As the current collector of the positive electrode, in addition to aluminum, stainless steel, nickel, titanium, etc., the surface of aluminum or stainless steel is preferably treated with carbon, nickel, titanium, or silver. Among them, aluminum and aluminum alloys are preferable. More preferred.

  As the negative electrode current collector, copper, stainless steel, nickel, and titanium are preferable, and copper or a copper alloy is more preferable.

  As the shape of the current collector, a film sheet is usually used, but a porous body, a foam, a molded body of a fiber group, and the like can also be used. The thickness of the current collector is not particularly limited, but is preferably 1 μm to 500 μm. Moreover, it is also preferable that the current collector surface is roughened by surface treatment.

<Production of secondary battery>
Here, production of the secondary battery of the present invention will be described. The shape of the secondary battery of the present invention can be applied to any shape such as a sheet, a corner, and a cylinder. A positive electrode active material or a mixture of negative electrode active materials is mainly used after being applied (coated), dried and compressed on a current collector.

  Preferable examples of the method for applying the mixture include a reverse roll method, a direct roll method, a blade method, a knife method, an extrusion method, a curtain method, a gravure method, a bar method, a dip method, and a squeeze method.

  Of these, blade method, knife method and extrusion method are preferable. Moreover, it is preferable that application | coating is implemented at the speed | rate of 0.1 m / min-100 m / min.

  Under the present circumstances, the surface state of a favorable coating layer can be obtained by selecting the said application | coating method according to the solution physical property and dryness of a mixture. Application may be performed one side at a time or both sides simultaneously.

  Furthermore, the application may be continuous, intermittent or striped. The thickness, length and width of the coating layer are determined by the shape and size of the battery, but the thickness of the coating layer on one side is preferably 1 μm to 2000 μm in a compressed state after drying.

  As a method for drying and dehydrating the electrode sheet coating, which is an embodiment of the secondary battery of the present invention, a method in which hot air, vacuum, infrared rays, far infrared rays, electron beams and low-humidity air are used alone or in combination can be used.

  The drying temperature is preferably adjusted in the range of 80 ° C to 350 ° C, more preferably in the range of 100 ° C to 250 ° C.

  The water content is preferably 2000 ppm or less for the entire battery, and preferably 500 ppm or less for each of the positive electrode mixture, the negative electrode mixture and the electrolyte composition.

As a sheet pressing method, a generally adopted method can be used, but a calendar pressing method is particularly preferable. Although the pressing pressure is not particularly ^{limited, 0.2t / cm 2 ~3t / cm} 2 is preferred.

  The pressing speed of the calendar press method is preferably 0.1 m / min to 50 m / min, and the pressing temperature is preferably room temperature to 200 ° C.

  The ratio of the negative electrode sheet width to the positive electrode sheet is preferably 0.9 to 1.1, particularly preferably 0.95 to 1.0. The content ratio of the positive electrode active material and the negative electrode active material varies depending on the compound type and the mixture formulation.

  Although the form of the secondary battery of the present invention is not particularly limited, it can be enclosed in various battery cells such as coins, sheets, and cylinders.

  The use of the secondary battery of the present invention is not particularly limited. For example, as an electronic device, a notebook computer, a pen input personal computer, a mobile personal computer, an electronic book player, a mobile phone, a cordless phone, a pager, a handy terminal, a mobile phone Fax, portable copy, portable printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, mini-disc, electric shaver, transceiver, electronic notebook, calculator, memory card, portable tape recorder, radio, backup power supply, memory card Etc. Other consumer products include automobiles, electric vehicles, motors, lighting equipment, toys, game equipment, road conditioners, watches, strobes, cameras, medical equipment (such as pacemakers, hearing aids, and shoulder grinders). Furthermore, it can be used for various military use and space use. Moreover, it can also combine with a solar cell.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these. Moreover, the structure of the compound used for an Example is shown below.

  In addition, although the display of "part" or "%" is used in an Example, unless there is particular notice, it represents "mass part" or "mass%".

Example 1
As described below, as the inorganic fine particles according to the present invention, inorganic fine particles 1 and 2 and MP-1 to MP-4 which are mesoporous silica particles which are preferred embodiments of the inorganic fine particles are prepared, and then an electrolyte composition is prepared. Prepared.

(1) Preparation of inorganic fine particles 1 and inorganic fine particles 2: (Preparation of Mg-Si particles)
Using a nano creator manufactured by Hosokawa Micron Co., Ltd., a raw material gas stream containing polydimethylsiloxane and a magnesium compound prepared so that MgO has a mass ratio shown in Table 1 and oxygen gas flow into the reaction space in a high-temperature atmosphere. In this way, white fine powdery inorganic fine particles 1 and 2 were formed. Table 4 shows the particle size measurement result by TEM observation of the obtained particles, the presence or absence of an absorption peak derived from silica by IR measurement, the composition analysis result by TEM / EDX of the particle cross section, and the crystal structure analysis result by XRD measurement. Table 4 shows the obtained particles. As a result, the inorganic fine particles 1 were particles in which magnesium silicate crystals were uniformly dispersed in amorphous silica. The inorganic fine particles 2 were particles in which the presence of amorphous silica could not be confirmed, and magnesium oxide crystals and magnesium silicate crystals were uniformly mixed.

(2) Production of mesoporous silica particles (MP particles) (preferred embodiment of inorganic fine particles)
(Preparation of mesoporous particles MP-1)
(3.645 g of cetyltrimethylammonium bromide was dissolved in 100 ml of pure water, and 4.41 ml of 1N hydrochloric acid was put therein.

  Next, while this solution was stirred at room temperature, a solution obtained by dissolving 11 g of tetraethoxysilane (TEOS) in 44 ml of pure water was added in 5 minutes.

Then, stirring was performed for 24 hours under irradiation with a high-pressure mercury lamp lamp (100 W) with a light amount of about 2.5 × 10 ¹⁶ / sec / cm ² .

  The resulting precipitate was filtered, washed thoroughly with ion-exchanged water, and dried under reduced pressure at 100 ° C. for 12 hours to obtain 3.2 g of a complex.

  The resulting composite was baked in air at 500 ° C. for 8 hours, then 200 ° C., 0.5 g of hexamethyldisilazane was added and surface treatment was performed for 2 hours, and mesoporous inorganic fine particles MP having mesopores -1 was obtained 2g.

The mesoporous inorganic fine particles 1 had a pore diameter of 4 nm, a specific surface area of 800 m ² / g, and an average particle diameter of 7 μm.

  The pore diameter and specific surface area were measured using BELSORP-mini II (automatic specific surface area / pore distribution measuring device manufactured by Nippon Bell Co., Ltd.).

  The average particle size was obtained by measuring 200 or more particles with a scanning electron microscope and determining the average value of the sphere equivalent particle size of each particle.

(Preparation of mesoporous silica particles MP-2 to MP-4)
In the same manner as the production of the mesoporous particles MP-1, mesoporous inorganic fine particles MP-2 to MP-4 having different pore diameters, specific surface areas, and average particle diameters are obtained by changing the amount of cetyltrimethylammonium bromide and the amount of TEOS. Produced.

  Table 5 shows the pore sizes, specific surface areas, and average particle sizes of MP-1 to MP-4 obtained as described above.

(3) Preparation of electrolyte composition (i) Preparation of electrolyte composition 1 3.2 g of ionic liquid IL-27 and 0.29 g of LiN (SO ₂ CF ₃ ) ₂ as an electrolyte salt were kneaded in a dry box. Electrolyte composition 1 was prepared.

(Ii) Preparation of electrolyte compositions 2 to 22 In the preparation of electrolyte composition 1, the ionic liquids shown in Table 6 were used, respectively, and 0.96 g of inorganic fine particles shown in Table 6 were used. Thus, electrolyte compositions 2 to 22 were prepared.

(Iii) Preparation of electrolyte compositions 23 to 28 3.2 g of ionic liquid described in Table 6, 0.29 g of LiN (SO ₂ CF ₃ ) ₂ as an electrolyte salt, 0.96 g of inorganic fine particles described in Table 6, monomer 0.16 g and 4.8 mg of polymerization initiator AIBN (azobisisobutylnitrile) were kneaded in a dry box, and further heated at 80 ° C. for 3 hours to prepare electrolyte compositions 23 to 28, respectively.

(Iv) Electrolyte compositions 29-34
3.2 g of ionic liquid described in Table 6, 0.29 g of LiN (SO ₂ CF ₃ ) ₂ as an electrolyte salt, 0.96 g of inorganic fine particles described in Table 6, 0.16 g of monomer, and polymerization initiator Irgacure 184 (Ciba (Made in Japan) 4.8 mg was kneaded in a dry box and irradiated with a high-pressure mercury lamp at an irradiation amount of 500 mJ / cm ² to prepare electrolyte compositions 29 to 34, respectively.

(4) Evaluation of electrolyte composition About each of the electrolyte compositions 1-34 obtained above, the property and ionic conductivity were evaluated as follows.

(A) Evaluation of properties of electrolyte composition Table 7 shows properties of the electrolyte compositions 1 to 34 at 25 ° C and properties at 80 ° C.

(B) Measurement of ion conductivity Each of the electrolyte compositions 1 to 34 was sandwiched between two platinum electrodes in a dry box, and the ion conductivity was measured by a complex impedance measurement method.

  The results obtained are shown in Table 7.

  From Table 7, compared with the comparative electrolyte compositions 1-3, the electrolyte compositions 4-34 of this invention can each be gelled (solidified) at 25 degreeC, and can hold | maintain a shape as a solid electrolyte, 80 It was found that at ℃, while exhibiting the properties of a liquid composition that can be applied to an electrode or the like, the ion conductivity was higher than that of the comparison.

Example 2
<< Production of Secondary Battery D-1 (also called Sheet Type Secondary Battery) >>
As described below, first, a positive electrode sheet was produced, and then a sheet type secondary battery D-1 was produced using the obtained positive electrode sheet.

(Preparation of positive electrode sheet)
As a positive electrode active material, 43 parts by mass of LiCoO ₂ , 2 parts by mass of flaky graphite, 2 parts by mass of acetylene black, 3 parts by mass of polyacrylonitrile as a binder were added, and 100 parts by mass of acrylonitrile was kneaded as a medium to prepare a slurry. Obtained.

  The obtained slurry was applied to an aluminum foil having a thickness of 20 μm using an extrusion type coater, dried and compression-molded by a calendar press machine, and then an aluminum lead plate was welded to the end, and the thickness was 95 μm. A positive electrode sheet having a width of 54 mm and a length of 49 mm was prepared and dehydrated and dried at 230 ° C. for 30 minutes in dry air having a dew point of −40 ° C. or lower.

(Production of sheet battery)
In a dry box, a positive electrode sheet having a width of 54 mm × a length of 49 mm and a 30 μm-thick non-woven TAPYRUS P22FW-OCS having a thickness of 60 μm cut to a width of 60 mm × a length of 60 mm are stacked to form an electrolyte composition 1 Of the negative electrode sheet (lithium-laminated copper foil (lithium film thickness 30 μm, copper foil film thickness 20 μm)) having a width of 55 mm and a length of 50 mm welded to the lead plate. The mixture was heated to 80 ° C. for 3 hours.

  Thereafter, an outer packaging material made of a laminate film of polyethylene (50 μm) -polyethylene terephthalate (50 μm) is used, and the four edges are heat-sealed under vacuum to be sealed, and a secondary battery (sheet type battery) D-1 is produced. did.

(Production of secondary batteries D-2 to D-34)
In the production of the secondary battery D-1, the secondary battery D-2 was prepared in the same manner except that each of the electrolyte compositions 2 to 34 shown in Table 6 was used instead of the electrolyte composition 1 and no nonwoven fabric was used. -D-34 was produced respectively.

<Evaluation of secondary battery>
For each of the obtained secondary batteries D-1 to D-34, the relative capacity and the repetition characteristics were evaluated as shown below, and the light resistance of the battery was further evaluated.

<< Relative capacity evaluation >>
About each of obtained secondary battery D-1 to D-34, it charged to voltage 2.6V-4.2V with the electric current of 0.2mA / cm < ² > using the measuring device charge / discharge measuring apparatus. After 10 minutes of rest, the battery was discharged to 2.6 V with a current of 0.2 mA / cm ² .

  This charge / discharge was repeated 10 times, and the discharge capacity at the 10th cycle was determined.

  This was examined for 10 batteries of the same formulation, and the average was taken as the capacity of the battery.

  Thus, the capacity | capacitance of each battery was calculated | required, the relative capacity | capacitance when the capacity | capacitance of the battery D-1 was set to 1 was calculated | required for the relative capacity | capacitance of the batteries D-2 to D-34, and it showed in Table 8.

<Evaluation of repetitive characteristics>
About each of obtained secondary battery D-1 to D-34, it charged to voltage 2.6V-4.2V with the electric current of 0.5 mA / cm < ² > using the said charging / discharging measuring apparatus, and 10 minutes After the rest, the battery was discharged at a current of 0.5 mA / cm ^{2 to} a battery voltage of 2.6V.

  This charge / discharge was repeated for 500 cycles, the discharge capacity at the 500th cycle was determined, the ratio to the discharge capacity at the 10th cycle was calculated, and the cycle capacity is shown in Table 8.

《Battery weather resistance evaluation》
Each of the secondary batteries D-1 to D-34 charged to a voltage of 2.6 V to 4.2 V with a current of 0.2 mA / cm ² was subjected to the method described in Example 1 of Japanese Patent Application Laid-Open No. 2008-159741 (organic An EL element number 104 and a sheet-like organic EL surface light emitter made of the above-prepared sheet-like secondary battery (same shape and area as each of D-1 to D-34) are connected to form a sheet. A lighting device was produced.

  These were left in the A environment room (room temperature 40 ° C., humidity 50%) and the B environment room (room temperature −20 ° C., humidity 20%) for 24 hours, and then the voltage dropped to ¼ of the initial emission luminance. The time (τ1 / 4) until the time of decrease was measured.

  The evaluation results are shown in Table 8.

  From Table 8, compared with the comparative secondary batteries D-1 to D-3, the secondary batteries of the present invention have large discharge capacities (shown as relative capacities in Table 8), and values of cycle capacity. From the above, it is apparent that the repetition characteristics are all good and the light resistance of the battery is remarkably excellent in both the A environment chamber and the B environment chamber.

  The above results will be described in detail. In the secondary batteries D-1 to D-3 produced using the comparative electrolyte composition, the discharge amount is remarkably reduced particularly when the charge and discharge are repeated 800 times. It can be seen that the repeated charge / discharge characteristics are not good.

  On the other hand, it can be seen that the secondary batteries D-4 to D-34 having the electrolyte composition of the present invention show extremely excellent durability with little decrease in discharge amount even when the charge / discharge cycle is repeated.

Claims (6)

An electrolyte composition comprising an ionic liquid represented by the following general formula (1), and further containing an electrolyte salt and inorganic fine particles.
General formula (1)
_{^{Z + N - (SO 2 F}} ) (X 1 -R F1)
[Wherein, Z ⁺ represents a quaternary ammonium cation, a quaternary phosphonium cation, a tertiary sulfonium cation, X ¹ represents —SO ₂ — or —CO—, and R ^F1 represents a perfluoroalkyl having 1 to 4 carbon atoms. Represents a group. ] The electrolyte composition according to claim 1, wherein the Z ⁺ is represented by the following general formula (2) or (3).

[Wherein, R ^{1 to} R ⁴ each represents an alkyl group, and any two groups of R ^{1 to} R ⁴ may form a ring together with the nitrogen atom. ]

[Wherein R ¹¹ and R ¹³ each represent an alkyl group, and R ¹² , R ¹⁴ and R ¹⁵ each represent a hydrogen atom, a halogen atom, an alkyl group, a halogenated alkyl group or an aryl group. ]   The electrolyte composition according to claim 1 or 2, wherein the inorganic fine particles are inorganic oxides.   The electrolyte composition according to claim 1, wherein the inorganic fine particles are mesoporous inorganic fine particles.   The electrolyte composition according to any one of claims 1 to 4, wherein the inorganic fine particles are inorganic fine particles containing two or more kinds of metals.   A secondary battery comprising the electrolyte composition according to claim 1.