JP2008218404A - Ionic conductive material and usage of same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ionic conductive material having higher ionic conductivity, and a nonacqueous electrolytic secondary battery having the ionic conductive material. <P>SOLUTION: The ionic conductive material contains a polymeric acid lithium salt. According to the polymeric acid lithium salt, the equivalent weight of a lithium contained in the polymeric acid lithium salt is ≤185 g/Li-mol, and the minimum of pKa is calculated at ≤4.5 when both ends of a repeated structure of the polymeric acid lithium salt are replaced with methyl groups and lithium cations of the polymeric acid lithium salt are replaced with protons. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ion conductive material, a nonaqueous electrolyte secondary battery including the material, and the like.

  Conventionally, a liquid electrolyte excellent in lithium ion conductivity has been used as an electrolyte of a lithium secondary battery. However, the liquid electrolyte has problems such as leakage and elution of an electrode active material.

  In recent years, solid electrolytes that do not have such problems, particularly polymer solid electrolytes that can easily form thin films, have attracted attention as electrolytes for lithium secondary batteries (see Patent Documents 1 to 8).

However, small cations such as lithium ions in the polymer electrolyte have a large interaction with oxygen atoms in the polymer chain. When ordinary lithium salts (for example, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiCF ₃ SO _3, etc.) are used, there is a problem that the transport number of the cation is lowered.

In order to improve the transport number of the cation, there is known an electrolyte obtained by mixing an ion conductive polymer and a polymer acid lithium salt such as a polylithium lithium methacrylate or a polystyrene sulfonate lithium salt (for example, a patent document). 9).
JP 62-219469 A (published September 26, 1987) JP 2006-210208 A (released on August 10, 2006) JP 2006-032296 A (published February 2, 2006) JP 2002-304986 A (released on October 18, 2002) JP 2002-050360 A (published February 15, 2002) Japanese Patent Laying-Open No. 2001-282859 (released on October 12, 2001) JP 2000-021448 A (published on January 21, 2000) Japanese Patent Laid-Open No. Sho 62-020263 (published January 28, 1987) JP 2000-21448 A (published on January 21, 2000)

  However, even when the electrolyte of Patent Document 9 is used, the value of ionic conductivity is not satisfactory.

  The present invention has been made in view of the above problems, and an object thereof is to realize an ion conductive material having higher ion conductivity and a nonaqueous electrolyte secondary battery including the material. .

  In order to solve the above-mentioned problems, the present inventor has intensively studied about realizing an ion conductive material that exhibits higher ion conductivity. As a result, in order to improve the ionic conductivity, the acidity of the polymer acid constituting the ionic conductive material is strong (that is, pKa is small), and the ionic conductivity of the ionic conductive material is smaller as the Li equivalent is smaller. As a result, the present invention has been completed.

  That is, in order to solve the above problems, the ion conductive material according to the present invention is an ion conductive material containing a polymer acid lithium salt, and the polymer acid lithium salt has a Li equivalent of 185 g / Li- The minimum value of pKa is 4.5 or less, calculated by replacing both ends of the repeating structure of the polymeric acid lithium salt with a methyl group and replacing the Li cation of the polymeric acid lithium salt with a proton. It is characterized by that.

  According to said structure, since the cation density | concentration in ion conductive material is high, and the lithium salt of polymeric acid with low pKa is used, the effect that an ion conductive material with high ion conductivity can be provided. Play.

  The ion conductive material according to the present invention is preferably an ion conductive material for a non-aqueous secondary battery.

  The electrolyte for a non-aqueous secondary battery according to the present invention is characterized by containing the ion conductive material according to the present invention in order to solve the above problems.

  According to said structure, since the said ion conductive material of this invention with high ionic conductivity is contained, there exists an effect that the electrolyte for non-aqueous secondary batteries with high ionic conductivity can be provided.

  Moreover, in order to solve the said subject, the nonaqueous electrolyte secondary battery which concerns on this invention is provided with the said electrolyte of this invention, a positive electrode, and a negative electrode, It is characterized by the above-mentioned.

  According to said structure, since the said electrolyte of this invention with high ionic conductivity is provided, there exists an effect that the nonaqueous electrolyte secondary battery of a high output density can be provided.

  As described above, the ion conductive material according to the present invention is an ion conductive material containing a polymer acid lithium salt, and the polymer acid lithium salt has a Li equivalent of 185 g / Li-mol or less, The minimum value of pKa calculated by replacing both ends of the repeating structure of the polymeric acid lithium salt with methyl groups and replacing the Li cation of the polymeric acid lithium salt with protons is 4.5 or less. .

  For this reason, there exists an effect that an ion conductive material with high ion conductivity can be provided.

  Moreover, the electrolyte for non-aqueous secondary batteries which concerns on this invention contains the said ion conductive material which concerns on this invention as mentioned above, It is characterized by the above-mentioned.

  For this reason, there exists an effect that the electrolyte for non-aqueous secondary batteries with high ion conductivity can be provided.

  Furthermore, as described above, the nonaqueous electrolyte secondary battery according to the present invention includes the above-described electrolyte of the present invention containing a nonaqueous electrolytic solution, a positive electrode, and a negative electrode.

  For this reason, the non-aqueous electrolyte secondary battery having a high output density can be provided.

  The present invention will be described in detail below. “Weight” is treated as a synonym for “mass”, and “wt%” is treated as a synonym for “mass%”. In addition, “A to B” indicating the range indicates that it is A or more and B or less, and “(meth) acrylate”, “(meth) acrylic acid” and the like are “acrylate or methacrylate” or “acrylic acid or It means “methacrylic acid” and the like.

[Li equivalent of polymer acid lithium salt]
The “Li equivalent” of the polymer acid lithium salt used in the present invention is the formula amount of the polymer acid lithium salt per mol of Li ions, specifically, the Li ions in 1 mol of the polymer acid lithium salt. The following formula Li equivalent (g / Li-mol) = molecular weight of polymer acid lithium salt / Li concentration in polymer acid lithium salt Can be calculated.

  The molecular weight of the polymer acid lithium salt may be a weight average molecular weight (Mw) value measured using a GPC apparatus in which a calibration curve is prepared using a standard molecular weight sample of polyethylene oxide.

The Li concentration of the polymeric acid lithium salt can be determined by an ion chromatograph analyzer that creates a calibration curve using a Li ion standard concentration sample. Specifically, 100% pure lithium chloride (LiCl) diluted to 1000 mg / L with ultrapure water is used as a calibration curve standard solution, and this is diluted with ultrapure water as appropriate. Li ion standard concentration sample, using the following conditions equipment: ion chromatograph system DX-500 (manufactured by Nippon Dionex)
Separation mode: ion exchange detector: electrical conductivity detector CD-20
Column: CS12A
Thus, a calibration curve can be created by performing ion chromatography analysis. The Li concentration of the polymer acid lithium salt was obtained by diluting 0.1 g of the polymer acid lithium salt 1000 times with ion-exchanged water, and using this solution, ion chromatography was performed under the same conditions as in the measurement of the Li ion standard concentration sample. Analysis is performed, and the Li ion concentration can be obtained based on the calibration curve.

[Minimum value of pKa calculated by replacing both ends of the repeating structure of the polymeric acid lithium salt with a methyl group and replacing the Li cation of the polymeric acid lithium salt with a proton]
“Minimum value of pKa calculated by replacing both ends of the repeating structure of the polymeric acid lithium salt with methyl groups and replacing the Li cation of the polymeric acid lithium salt with protons” (hereinafter referred to as “polymer “Minimum pKa value of acid” is described as “ACD / pKa DB Version 7.0” (manufactured by Advanced Chemistry Development Inc.) using both ends of the repeating structure of the polymer acid lithium salt as methyl groups. It is a pKa value calculated by replacing the Li cation of the molecular acid lithium salt with a proton. “Apparent Constants, Approximated” was used as the type of calculation.

  If the minimum pKa value of the polymer acid cannot be calculated using “ACD / pKa DB Version 7.0”, “TURBOMOLE Version 5.8” (manufactured by COSMO logic) is used and TZVP is used as the basis function. Perform structure optimization calculation and COSMO-RS method calculation, and “COSMO therm Version C2.1 Release 01.06” (manufactured by COSMO logic Co., Ltd.). It can be determined by calculating the pKa when the terminal is a methyl group and the Li cation of the polymer acid lithium salt is replaced with a proton.

When the polymer acid lithium salt is copolymerized with a plurality of monomers and there are a plurality of repeating structures of the polymer acid lithium salt, the pKa value (for each repeating structure) PKa value calculated by replacing the Li cation of the polymer acid lithium salt with a proton at both ends, and multiplying the minimum pKa value of the pKa value by the molar content of each repeating structure. The minimum pKa value of the polymer acid may be used. Specifically, for example, when the polymer acid lithium salt is composed of 70 mol% of the repeating unit A and 30 mol% of the repeating unit B,
Minimum pKa value of polymer acid = (minimum pKa value calculated from repeating unit A) × 0.7 + (minimum pKa value calculated from repeating unit B) × 0.3
Thus, the minimum pKa value of the polymer acid can be obtained.

[Ion conductive material]
The ion conductive material according to the present embodiment is an ion conductive material containing a polymer acid lithium salt, and the polymer acid lithium salt has a Li equivalent of 185 g / Li-mol or less, and the polymer The minimum value of pKa (minimum pKa value of the polymer acid) calculated by replacing both ends of the lithium acid salt repeating structure with methyl groups and replacing the lithium cation of the polymer acid lithium salt with protons is 4.5 or less. .

  Examples of the ion conductive material according to the present embodiment include additives for imparting conductivity to the electrolyte, the positive electrode, and / or the negative electrode.

  The Li equivalent of the polymer acid lithium salt is more preferably 170 g / Li-mol or less, still more preferably 160 g / Li-mol or less, and particularly preferably 150 g / Li-mol or less.

  The lower limit of the above range of the Li equivalent of the polymeric acid lithium salt is not particularly limited, but is more preferably 30 g / Li-mol, still more preferably 40 g / Li-mol, and particularly preferably 50 g / Li. -Mol, most preferably 60 g / Li-mol.

  Further, the minimum pKa value of the polymer acid is more preferably 4.0 or less, further preferably 3.0 or less, particularly preferably 1.0 or less, and most preferably 0.0 or less. is there.

  The lithium polymer acid salt is not particularly limited as long as the Li equivalent is in the above range and the pKa value is in the above range. Examples of the polymer acid lithium salt include acrylic acid or a lithium salt thereof (hereinafter, “˜acid or lithium salt thereof” is referred to as “˜acid (salt)”), methacrylic acid (salt), maleic acid (salt), Monomethyl maleate (salt), monoethyl maleate (salt), fumaric acid (salt), monomethyl fumarate (salt), monoethyl fumarate (salt), itaconic acid (salt), monomethyl itaconic acid (salt), monoethyl itaconic acid (Salt), methylene malonic acid, monomethyl methylene malonate, cinnamic acid, crotonic acid, allyl sulfonic acid (salt), vinyl sulfonic acid, styrene sulfonic acid (salt), sulfonic acid (salt) polyaniline, acryloyloxyalkylphosphonic acid (Salt), methacryloyloxyalkylphosphonic acid (salt), dicyanomethide acrylate (salt), dimethacrylate Anometide (salt), vinyloxysulfonic acid (salt), citraconic acid (salt), aconitic acid (salt), methallylsulfonic acid (salt), 3-allyloxy-2-hydroxy-propanesulfonic acid (salt), sulfoethyl (salt) Any one or more of acid group-containing monomers such as (meth) acrylate (salt), sulfopropyl (meth) acrylate (salt), 2-hydroxysulfopropyl (meth) acrylate (salt), sulfoethylmaleimide (salt) Polymers that are combined and (co) polymerized are listed. Examples of the acid group-containing monomer include the carboxylic acid (salt), the sulfonic acid (salt), the phosphonic acid (salt), and the monomer containing an acid group such as methide acid (salt). The monomer is not limited.

  The polymer lithium acid salt need not be a polymer obtained by polymerizing only an acid group-containing monomer, and may be a polymer obtained by copolymerizing a monomer that does not contain an acid group. Good.

  Examples of monomers not containing an acid group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and n-nonyl. (Meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, cyclohexylmethyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, methoxyethoxyethyl (meth) acrylate, ethoxyethoxyethyl ( (Meth) acrylate, methoxypolyethylene glycol (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol (meth) acrylate Monofunctional (meth) such as relate, N, N-dimethylaminoethyl (meth) acrylate, butyl α-hydroxymethyl acrylate, neopentyl glycol mono (meth) acrylate, 1,4-butanediol mono (meth) acrylate Acrylate; monofunctional (meth) acrylamide such as N, N-dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, etc .; methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, 2-ethylhexyl vinyl ether, n-nonyl vinyl ether , Lauryl vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl Monofunctional vinyl ethers such as ether, methoxypolyethylene glycol vinyl ether, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether; N-vinylpyrrolidone, N-vinylcaprolactam, N-vinyl -N-methylformamide, N-vinylimidazole, N-vinylformaldehyde, N-vinylacetamide, and other monofunctional N-vinyl compounds; styrene, α-methylstyrene, vinyltoluene, allyl glycidyl ether, (meth) allyl alcohol Monofunctional vinyl compounds such as ethylene oxide adducts and ethylene oxide adducts of isoprenol; dimethyl maleate, di maleate Monofunctional α, β-unsaturated compounds such as chill, dimethyl fumarate, diethyl fumarate, dimethyl itaconate, diethyl itaconate, dimethyl methylenemalonate, ethyl cinnamate, methyl crotonate, ethyl crotonate; methyl glycidyl Ether, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, 2-ethylexyl glycidyl ether, n-nonyl glycidyl ether, lauryl glycidyl ether, cyclohexyl glycidyl ether, methoxyethyl glycidyl ether, ethoxyethyl glycidyl ether, methoxyethoxyethyl glycidyl ether Monofunctional epoxy compounds such as ether, ethoxyethoxyethyl glycidyl ether, methoxypolyethylene glycol glycidyl ether, etc .; 3-methyl 3-hydroxymethyloxetane, 3-ethyl-3-hydroxymethyloxetane, 3-methyl-3-phenoxymethyloxetane, 3-ethyl-3-phenoxymethyloxetane, 3-methyl-3- (2-ethylhexyloxymethyl) Monofunctional alicyclic ether compounds such as oxetane; ethylene glycol diacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, propylene glycol diacrylate, butylene glycol diacrylate, hexanediol diacrylate, cyclohexanediol diacrylate, cyclohexanedimethanol di Acrylate, bisphenol A alkylene oxide diacrylate, bisphenol F alkylene oxide diacrylate, trimethylol group Lopantriacrylate, dimethylolpropane tetraacrylate, glycerin triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ethylene oxide-added trimethylolpropane triacrylate, ethylene oxide-added ditrimethylolpropane tetraacrylate, ethylene Polyfunctional acrylates such as oxide-added pentaerythritol tetraacrylate and ethylene oxide-added dipentaerythritol hexaacrylate; ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol di Nyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, bisphenol F alkylene oxide divinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, dipenta Erythritol hexavinyl ether, ethylene oxide-added trimethylolpropane trivinyl ether, ethylene oxide-added ditrimethylolpropane tetravinyl ether, ethylene oxide-added pentaerythritol tetravinyl ether, ethylene oxide-added dipentaerythritol hexavinyl ether Polyfunctional vinyl and the like; polyfunctional vinyl compounds such as divinylbenzene; and the like. These may be used alone or in combination of two or more.

  Specific examples of the polymer acid lithium salt include polymers having a structure shown in Table 1.

In the table, the value of pKa marked with “* 1” is “TURBOMOLE Version 5.8” (manufactured by COSMO logic), and TZVP is used as the basis function for structural optimization calculation and COSMO-RS method calculation. This is a value calculated by performing pKa calculation at 25 ° C. in an aqueous solvent by “COSMO therm Version C2.1 Release 01.06” (manufactured by COSMO logic). The other pKa values were determined by using “ACD / pKa DB Version 7.0” (manufactured by Advanced Chemistry Development Inc.), using both ends of the repeating structure of the polymeric acid lithium salt as methyl groups, This is a value calculated by replacing the Li cation of the salt with a proton.

  In the polymer acid lithium salt exemplified in Table 1, all acid groups are Li salts, but the polymer acid lithium salt that can be used in the present embodiment is not limited thereto. If the Li equivalent is 185 g / Li-mol or less and the minimum pKa value of the polymer acid is 4.5 or less, the same effect can be obtained even if all acid groups are not Li salts. However, when all of the acid groups are Li salts as in the polymer acid lithium salt shown in Table 1, the Li equivalent can be reduced to the maximum, so that the effect is particularly great.

  Further, in the polymer acid lithium salt exemplified in Table 1, if the Li equivalent is 185 g / Li-mol or less and the minimum pKa value of the polymer acid is 4.5 or less, the polymer main chain and / or Alternatively, the side chain may be substituted with a substituent such as an alkyl group or an oxyethylene group.

  However, since the Li equivalent is higher when the formula weight of the polymer acid lithium salt is smaller, it is more preferable that a substituent other than the acid group is not substituted on the main chain and / or side chain of the polymer.

  Furthermore, in the homopolymerization, even if the monomer is a polymer acid lithium having a Li equivalent greater than 185 g / Li-mol and / or a polymer acid having a minimum pKa value greater than 4.5, By copolymerizing, it is possible to obtain a high molecular acid lithium having a Li equivalent of 185 g / Li-mol or less and a minimum pKa value of the polymer acid of 4.5 or less.

  For example, the following structure in which the Li equivalent of the polymeric acid lithium obtained when homopolymerized is 213.18 g / Li-mol and the minimum pKa value of the polymeric acid is 1.70

Monomer AMPSLi and the polymer acid lithium obtained by homopolymerization have a Li equivalent of 78.00 g / Li-mol and the minimum pKa value of the polymer acid is 4.80.

As shown in Table 2, when the content of the monomer LiA in the total monomer is in the range of about 21 mol% to 90 mol%, the lithium polymeric acid obtained by polymerizing the monomer LiA Is 185 g / Li-mol or less, and the polymer acid lithium has a minimum pKa value of 4.5 or less.

  Similarly, the following structure in which the Li equivalent of the polymeric acid lithium obtained when homopolymerized is 190.15 g / Li-mol and the minimum pKa value of the polymeric acid is −0.48:

As shown in Table 3, the polymer acid lithium obtained by polymerizing the monomers SSLi and LiA in the case where the content of all monomers LiA in the monomer is in the range of about 5 mol% to 94 mol%. , Li equivalent is 185 g / Li-mol or less, and the polymer acid lithium having the minimum pKa value of the polymer acid is 4.5 or less.

  The polymer acid lithium salt can be produced, for example, by polymerizing the above-described acid salt-containing monomer lithium salt by a conventionally known method. Further, it can also be produced by polymerizing the above-mentioned acid group-containing monomer by a conventionally known method, followed by lithium chloride.

  Examples of the lithiation reagent used when performing the above lithium chloride include lithium carbonate, lithium hydroxide, lithium metal and the like, and lithium carbonate is more preferable from the viewpoint that a high-purity product is commercially available and easily available. .

  The molecular weight of the polymeric acid lithium salt is not particularly limited, but is preferably in the range of 500 to 10 million, more preferably in the range of 5 to 5 million, and 1,000 to 1 million. Is more preferably within the range of 1,000 to 500,000.

  The ion conductive material according to the present embodiment may contain an ion conductive polymer in addition to the above polymer acid lithium salt. Examples of the ion conductive polymer include polyalkylene oxides such as polyethylene oxide, polypropylene oxide, and polyethylene oxide-polypropylene oxide copolymers, polymethyl methacrylate, and polyacrylonitrile.

  The content of the polymer acid lithium salt in the ion conductive material according to the present embodiment is preferably in the range of 1 to 100% by weight, and more preferably in the range of 10 to 100% by weight. More preferably, it is in the range of 20 to 100% by weight, particularly preferably in the range of 50 to 100% by weight, and most preferably in the range of 75 to 100% by weight.

  The content of the ion conductive polymer in the ion conductive material according to the present embodiment is preferably in the range of 0 to 50% by weight, and preferably in the range of 0 to 20% by weight. More preferably, it is more preferably in the range of 0 to 15% by weight, particularly preferably in the range of 0 to 10% by weight, and most preferably in the range of 0 to 5% by weight.

  As an application of the ion conductive material according to the present embodiment, for example, a primary battery, a battery having a charging and discharging mechanism such as a lithium (ion) secondary battery or a fuel cell, an electrolytic capacitor, an electric double layer capacitor, Examples include electrochemical devices such as lithium ion capacitors, solar cells, and electrochromic display elements. These are generally composed of a pair of electrodes and an ionic conductor filling between them.

[Nonaqueous electrolyte secondary battery]
The non-aqueous electrolyte secondary battery according to the present embodiment includes the above-described electrolyte containing a non-aqueous electrolyte, a positive electrode, and a negative electrode.

  The nonaqueous electrolyte secondary battery according to the present embodiment can be manufactured by a conventionally known method described in Patent Document 12 described above in “Background Art”, for example.

  As the non-aqueous electrolyte, a conventionally known non-aqueous electrolyte can be used, and is not particularly limited. For example, cyclic carbonates such as ethylene carbonate, propylene carbonate, vinylene carbonate, butylene carbonate, dimethyl carbonate, Examples thereof include a mixed solvent with a low boiling point solvent such as diethyl carbonate, methyl ethyl carbonate, 1,2-diethoxyethane, 1,2-dimethoxyethane, ethoxymethoxyethane.

As the positive electrode, it is possible to use a material used for conventional positive electrode, particularly but not limited to, for _example, LiCoO _2, LiNiO _2, LiMnO 2, LiFeO lithium-containing transition metal oxides such as _2.

  As the negative electrode, materials used for conventionally known negative electrodes can be used, and are not particularly limited. For example, graphite such as natural graphite and artificial graphite, carbon materials such as coke, organic fired body, lithium-aluminum, and the like. Alloy, lithium-magnesium alloy, lithium-indium alloy, lithium-thallium alloy, lithium-lead alloy, lithium-bismuth alloy and other lithium alloys, or one or more of titanium, tin, iron, molybdenum, niobium, vanadium, zinc, etc. A metal oxide containing 2 or more types and a metal sulfide are mentioned.

〔Example〕
EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to a following example.

[Production Example 1] Synthesis of polymeric acid lithium salt To a four-necked flask equipped with a stirrer, thermometer, gas inlet tube, dropping funnel and condenser tube was added 12.4 g of vinyloxysulfonic acid and 25.0 g of dehydrated THF. The mixture was stirred and refluxed at 65 ° C. under a nitrogen stream. Thereafter, a solution obtained by diluting 0.124 g of 2,2′-azobis (2,4-dimethylvaleronitrile) (Wako Pure Chemical Industries, Ltd .: V-65), which is a polymerization initiator, with 5 g of THF was noted for heat generation. While slowly dropping. After reacting at 65 ° C. for 4 hours, the polymerization was completed.

  To the obtained polymerization reaction liquid, 3.7 g of lithium carbonate was added and stirred at room temperature for 2 hours to carry out the reaction. In order to remove unreacted lithium carbonate from the reaction solution, it was filtered with a 0.5 μm hydrophilic PTFE filter, and the filtrate was condensed and dried to obtain lithium polyvinyloxysulfonate (P-1). When the molecular weight of the obtained compound (P-1) was measured by GPC, the number average molecular weight (Mn) was 13,000 and the weight average molecular weight (Mw) was 24,000. The lithium ion concentration by ion chromatography (IC) was 192 Li-mol / g-polymer, and the Li equivalent was 125 g / Li-mol. Further, the minimum pKa value of the polymer acid is −3.43 as shown in Table 1.

[Example 1]
3 parts by weight of compound (P-1) is added and mixed with 12 parts by weight of ethylene carbonate (EC) and dissolved, and this is heated at 130 ° C. for 30 minutes under sealing to obtain a uniform semi-solid viscous material. It was. The obtained viscous material had an ionic conductivity at 25 ° C. of 1.4 × 10 ⁻³ S / cm.

  [Production Example 2] Synthesis of polymeric acid lithium salt

(1) Synthesis of 4-styrylmagnesium bromide 6.2 parts by weight of magnesium was weighed into a four-necked flask equipped with a stirrer, a thermometer, and a gas introduction tube, and after stirring overnight by heating with a heat blaster under vacuum, The pressure was released with nitrogen, 300 parts by weight of THF and a small amount of dibromoethane were sequentially added and stirred.

  When the heat generation due to the activation of Mg could be confirmed, the container was cooled to 0 to -20 ° C, and 23.5 parts by weight of bromostyrene was dropped from a newly installed dropping funnel.

  The reaction was continued while adjusting the refrigerant temperature and the dropping rate so that the temperature rise due to reaction heat was suppressed and the temperature of the reaction solution was 0 to -20 ° C. After completion of the dropwise addition, the mixture was heated to room temperature and stirred overnight to complete the reaction, and then unreacted magnesium pieces were removed to obtain 4-styrylmagnesium bromide.

(2) Synthesis of dimethoxy-4-styryl-borane After cooling the 4-styrylmagnesium bromide obtained in (1) to −78 ° C., 17.4 parts by weight of B (OMe) ₃ dissolved in 90 parts of THF Was added dropwise and stirred at −78 ° C. for 20 minutes, then warmed to room temperature and stirred for 1 hour to complete the reaction.

(3) Synthesis of potassium trifluoro-4-styryl-borate After cooling the reaction solution obtained in (2) to 0 ° C. and adding 50.2 parts by weight of KHF ₂ in 5 portions, water 92. 5 parts by weight was added and stirring was continued for 30 minutes. The temperature was further raised to room temperature, and stirring was continued overnight to complete the reaction.

  The reaction solution was concentrated and dried, then the solution extracted with acetone was concentrated, dried and recrystallized from acetone / ethanol to obtain potassium trifluoro-4-styrylborate.

(4) Synthesis of lithium trifluoro-4-styrylborate 1000 parts by weight of an ion exchange resin (Amberlite IR120B-H, manufactured by Organo Corporation) was filled in a column tube, sufficiently washed with ultrapure water, and then 1 mol / liter of LiOH. l After passing 10,000 parts by weight of an aqueous solution and replacing the acid of the ion exchange resin with lithium, it was washed thoroughly with ultrapure water to wash away excess LiOH.

  By concentrating the aqueous solution obtained by passing 1000 parts by weight of the aqueous solution (3) prepared to 5% by weight through an ion exchange resin, a 20% by weight lithium trifluoro-4-styrylborate aqueous solution was obtained.

FIG. 1 shows the ¹ H-NMR measurement result of the obtained compound, FIG. 2 shows the ¹⁹ F-NMR measurement result, and FIG. 3 shows the IR measurement result. From these results, it was confirmed that lithium trifluoro-4-styrylborate was synthesized.

(5) Synthesis of poly (lithium trifluoro-4-styrylborate) After nitrogen bubbling to the aqueous solution obtained in (4), 1 part by weight of a 5% by weight ammonium persulfate aqueous solution was added, and the mixture was allowed to stand in a constant temperature bath at 70 ° C for 3 hours. Thus, a polymerization reaction was performed to obtain a poly (lithium trifluoro-4-styryl borate) aqueous solution.

  As a result of GPC analysis of the obtained polymer, the number average molecular weight (Mn) was 19,000, and the weight average molecular weight (Mw) was 61,000.

Further, FIG. 4 shows the ¹ H-NMR measurement result of the obtained polymer, FIG. 5 shows the ¹⁹ F-NMR measurement result, and FIG. 6 shows the ¹³ C-NMR measurement result. From these results, it was confirmed that poly (lithium trifluoro-4-styryl borate) was synthesized.

[Example 2]
Instead of using the compound (P-1), the same method as in Example 1 was used except that the polymer obtained by condensing and drying the aqueous solution obtained in (5) of Production Example 2 was used. When the ionic conductivity at 25 ° C. was measured, it was 2.1 × 10 ⁻³ S / cm.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. That is, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.

  Since the ion conductive material of the present invention has high ion conductivity, it can be suitably used for applications such as electrolytes for secondary batteries such as non-aqueous electrolyte secondary batteries.

It is drawing which shows the measurement result of ¹ H-NMR of lithium trifluoro-4-styryl borate. It is drawing which shows the measurement result of ¹⁹ F-NMR of lithium trifluoro-4-styryl borate. It is drawing which shows the measurement result of IR of lithium trifluoro-4-styryl borate. It is drawing which shows the measurement result of ¹ H-NMR of poly (lithium trifluoro-4-styryl borate). It is drawing which shows the measurement result of ¹⁹ F-NMR of a poly (lithium trifluoro- 4-styryl borate). It is drawing which shows the measurement result of ¹³ C-NMR of poly (lithium trifluoro-4-styryl borate).

Claims (4)

It is an ion conductive material containing a polymer acid lithium salt,
The polymer acid lithium salt has a Li equivalent of 185 g / Li-mol or less,
The minimum value of pKa calculated by replacing both ends of the repeating structure of the polymeric acid lithium salt with a methyl group and replacing the Li cation of the polymeric acid lithium salt with a proton is 4.5 or less. Ion conductive material.   The ion conductive material according to claim 1, which is an ion conductive material for a non-aqueous secondary battery.   An electrolyte for a non-aqueous secondary battery, comprising the ion conductive material according to claim 2.   A non-aqueous electrolyte secondary battery comprising the electrolyte according to claim 3, a positive electrode, and a negative electrode.

Images