JP5008471B2 - Non-aqueous electrolyte, non-aqueous electrolyte secondary battery and manufacturing method thereof - Google Patents

Description

  The present invention uses a non-aqueous electrolyte containing a compound having at least an ether skeleton and an alkali metal sulfonate sulfonate in the molecule, and the non-aqueous electrolyte, and has a high temperature storage stability even under high voltage. The present invention relates to a water electrolyte secondary battery.

  A lithium ion secondary battery (non-aqueous electrolyte secondary battery) configured using a non-aqueous electrolyte has characteristics of high voltage (operation voltage 4.2 V) and high energy density. The demand for these devices is expanding rapidly, and now a position as a standard battery for mobile information devices such as mobile phones and notebook computers has been established. Naturally, along with the high performance and multi-functionality of portable devices, there is a need for higher performance (for example, higher capacity and higher energy density) for lithium-ion secondary batteries as power sources. ing. In order to meet this demand, various methods such as increasing the density by increasing the filling rate of the electrodes, increasing the charging depth of the current active material (especially the negative electrode), and developing a new active material with a high capacity have been studied. Yes. In reality, the capacity of the lithium ion secondary battery is reliably increased by these methods.

  This lithium ion secondary battery often uses a non-aqueous electrolyte obtained by dissolving an electrolyte salt in a non-aqueous solvent (organic solvent) as the electrolyte (electrolyte).

On the other hand, a lithium ion secondary battery using a solid electrolyte instead of a liquid non-aqueous electrolyte is also known. For example, Patent Document 1 proposes a lithium ion secondary battery configured by using, as an electrolyte, an ion conductive polymer material obtained by dissolving a specific salt in a polymer material having a polyether type amorphous structure. Has been. However, the ion conductive polymer substance disclosed in Patent Document 1 itself has a conductivity of 10 ⁻⁵ S · cm ⁻¹ or less even at a high temperature of 60 ° C. or higher, for example. It is difficult to say that the electrolyte applied to the secondary battery has sufficient performance.

  The positive electrode of the lithium ion secondary battery is prepared, for example, by preparing a positive electrode mixture-containing slurry by dispersing a positive electrode mixture containing a positive electrode active material, a conductive additive and a binder in a solvent. It is applied to the surface of a metal foil or the like to be manufactured and dried to produce a positive electrode mixture layer. Patent Document 2 includes a lithium ion secondary battery having a positive electrode prepared by containing a sulfonic acid having a specific structure or a lithium sulfonate salt in a positive electrode mixture-containing slurry and preventing gelation of the positive electrode mixture-containing slurry, That is, a lithium ion secondary battery having a positive electrode containing a sulfonic acid having a specific structure or a lithium sulfonate is disclosed. In Patent Document 2, even if the positive electrode contains a sulfonic acid or a sulfonic acid lithium salt having the specific structure, battery characteristics are not impaired.

JP 62-64073 A Japanese Patent Application Laid-Open No. 2003-173782

By the way, as one of the performance improvement of a lithium ion secondary battery, the expansion of the charge depth of a positive electrode active material by the rise in charge voltage attracts attention. For example, a cobalt composite oxide (LiCoO ₂ ), which is an active material of a lithium ion secondary battery having an operating voltage of 4.2 V class, is charged when charged to 4.3 V on the basis of Li, which is a currently used charging condition. While the capacity is about 155 mAh / g, it is about 190 mAh / g or more when charged to 4.50V. Thus, the utilization rate of a positive electrode active material becomes large by the improvement of a charging voltage.

  However, as the voltage of the battery increases, the capacity and energy density of the battery improve. On the other hand, not only the safety of the battery and the charge / discharge cycle characteristics deteriorate, but also the swelling during high-temperature storage becomes a serious problem.

  Conventionally, there have been proposals for techniques for solving problems such as battery safety, deterioration of charge / discharge cycle characteristics, and battery swelling. For example, an additive such as a specific cyclic sulfate is added to the non-aqueous electrolyte of a lithium ion secondary battery, and the battery is charged to form a dense film derived from the additive on the negative electrode surface. A technique is known that solves the above-described problems associated with the high voltage of a battery by a mechanism that continuously suppresses the reaction between the nonaqueous solvent in the aqueous electrolyte and the negative electrode.

  However, in the film formed by adding a conventionally known additive to the non-aqueous electrolyte, the ionic conductivity is insufficient, so the characteristics of the battery are reduced, and the film is structurally unstable, Since dissolution and growth of the film are repeated, the effect of suppressing swelling during high-temperature storage is not always sufficient. In addition, when the potential of the positive electrode at the completion of charging of the battery becomes a high voltage of, for example, 4.35 V or more on the basis of Li, it is possible to suppress deterioration in charge / discharge cycle characteristics or to increase the temperature by simply applying these techniques. Swelling suppression during storage (especially swelling suppression during high-temperature storage) cannot be sufficiently achieved.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a non-aqueous electrolyte secondary battery having good high-temperature storage characteristics even in a high-voltage charged state, and the non-aqueous electrolyte secondary battery. The object is to provide a non-aqueous electrolyte that can be configured.

  The non-aqueous electrolyte solution of the present invention that has achieved the above object is characterized by having a non-aqueous solvent, an electrolyte salt, and a sulfonate represented by the general formula (1).

[Wherein, R ¹ and R ² are alkylene or phenylene having 1 to 6 carbon atoms in which hydrogen may be substituted with fluorine, and may be the same or different. M is an alkali metal element, m and n are integers of 0 to 100, and 1 ≦ m + n ≦ 100. X is hydrogen or a group represented by any of the following formulas (2) to (5). ]

[In the formulas (2) to (5), M ′ is an alkali metal element, and may be the same as or different from M in the formula (1). ]

The non-aqueous electrolyte secondary battery of the present invention is characterized by having a positive electrode, a negative electrode, a separator, and the non-aqueous electrolyte of the present invention.
Furthermore, the manufacturing method of the non-aqueous electrolyte secondary battery of this invention charges the non-aqueous electrolyte secondary battery which has a positive electrode, a negative electrode, a separator, and the non-aqueous electrolyte in any one of Claims 1-8. The film is formed on the surface of the positive electrode by reacting the sulfonate in the non-aqueous electrolyte with the positive electrode.

  In general, in a charged nonaqueous electrolyte secondary battery, the metal oxide as the positive electrode active material exhibits a very strong oxidizing property in a high potential state. Therefore, the nonaqueous electrolyte used as a solvent for the nonaqueous electrolyte solution on the positive electrode surface Reacts with solvent and decomposes. Particularly when charged at a high voltage, this decomposition reaction becomes violent. Such a decomposition reaction of the non-aqueous solvent causes swelling when a non-aqueous electrolyte secondary battery charged at a high voltage is stored at a high temperature.

  The inventor of the present invention pays attention to the introduction of a special functional group into an alkali metal salt having a polyether type amorphous structure to form an ionic liquid. When a compound (sulfonic acid salt) introduced into one molecule together with an alkali metal base is contained in a non-aqueous electrolyte and a battery is constructed using the non-aqueous electrolyte, when charged (particularly charged at a high voltage), The sulfonate reacts with the positive electrode to form a film on the surface of the positive electrode, the polyether of the film can improve the ionic conductivity of the film, and the molecular structure and molecular weight of the sulfonate are controlled. The inventors have found that the viscosity can be controlled, and have completed the present invention.

  According to the present invention, it is possible to provide a non-aqueous electrolyte secondary battery having good high-temperature storage characteristics even in a high-voltage charged state, and a non-aqueous electrolyte that can constitute the non-aqueous electrolyte secondary battery. it can.

  In the nonaqueous electrolytic solution of the present invention, the sulfonate represented by the general formula (1) is used. Such a sulfonate has a high ion conductivity because a segment having an ether bond is introduced. When a battery is constructed using the non-aqueous electrolyte, the sulfonate reacts with the positive electrode to form a protective film on the surface of the positive electrode. Since the formed protective film is structurally stable, the reaction between the positive electrode and the nonaqueous electrolytic solution is prevented to suppress the swelling of the battery. Further, since the protective film has high ion conductivity, even if it is formed, the influence on the load characteristics of the battery is small, and it is difficult to adversely affect the performance of the battery. The sulfonic acid salt also reacts with the negative electrode.

  In the general formula (1), m + n represents the length of the ether skeleton portion (bonded portion of the oxypropylene unit and the oxyethylene unit), and this value is 1 or more and 100 or less, and when m + n is greater than 100, The alkali metal base of sulfonic acid, which is a functional group (hereinafter sometimes simply referred to as “sulfonic acid metal base”) may be trapped inside the molecule, or the solubility in a non-aqueous solvent may be reduced. . Note that m + n is preferably 5 or more, and preferably 20 or less, from the viewpoints of affinity for the non-aqueous solvent and the electrolyte salt and ion conductivity.

  M and n are each an integer of 0 or more and 100 or less, and m is preferably 0 or more, and preferably 20 or less. Furthermore, n is preferably 50 or less.

  In the sulfonate, the oxypropylene unit and the oxyethylene unit may be bonded while forming a block, or may be bonded at random.

In the general formula (1), R ¹ and R ² are alkylene or phenylene having 1 to 6 carbon atoms in which hydrogen may be substituted with fluorine, and may be the same or different. Among these, both R ¹ and R ² are preferably methylene (—CH ₂ —), ethylene (—CH ₂ —CH ₂ —), and propylene (—CH ₂ —CH ₂ —CH ₂ —).

  In the general formula (1), M is an alkali metal element, preferably Li, Na, or K, and particularly preferably Li.

  In the general formula (1), X is hydrogen or a group represented by any one of the above formulas (2) to (5), and is a group represented by any one of the above formulas (2) to (5). It is preferable that it is a group (sulfonic acid metal base) represented by the formula (2).

  In the group represented by any one of the formulas (2) to (5), M ′ is an alkali metal element, preferably Li, Na, or K, and particularly preferably Li. In the sulfonate represented by the general formula (1), when X is a group represented by any one of the formulas (2) to (5), the alkali metal element M ′ is an alkali metal element M. May be the same or different.

Among the sulfonates represented by the general formula (1), for example, R ¹ and R ² are alkylene having 1 to 6 carbon atoms (Note that R ¹ and R ² may be the same or different. R ¹ and R ² are each preferably more preferably methylene, ethylene, or propylene), m = 0, M is Li, and X is represented by the formula (2). And sulfonates wherein M ′ is Li are particularly preferred.

  The content of the sulfonate in the non-aqueous electrolyte is preferably 0.05% by mass or more in the total amount of the non-aqueous electrolyte from the viewpoint of more effectively exerting the action of the sulfonate. More preferably, it is 5 mass% or more. If the content of the sulfonate in the non-aqueous electrolyte is too large, the viscosity of the non-aqueous electrolyte may become too high and the load characteristics of the battery may decrease, and the cost of the non-aqueous electrolyte may be reduced. Therefore, the content is preferably 10% by mass or less, and more preferably 5% by mass or less.

  The sulfonate according to the present invention having both a polyether skeleton and a metal sulfonate group in the molecule has an ether segment and also has an intramolecular ion, and thus exhibits a liquid state at room temperature regardless of the high molecular weight. Is substantially a kind of ionic liquid. In addition, this sulfonate has a high affinity for non-aqueous solvents and electrolyte salts, and can form a protective film having a higher ionic conductivity on the surface of the positive electrode.

  That is, in the battery using the non-aqueous electrolyte having a sulfonate according to the present invention, the sulfonate metal base of the sulfonate first reacts with the positive electrode active material, whereby the protective film having an ether bond is formed on the positive electrode surface. To form. Since this protective film has high ion conductivity and is structurally stable, it can prevent the reaction between the positive electrode and the non-aqueous electrolyte and suppress the swelling of the battery. High-temperature storage characteristics in a voltage charged state) can be effectively improved.

In addition, since the protective film is structurally stable as described above, even if a highly oxidizable nickel-containing oxide (such as lithium nickel oxide such as LiNiO ₂ ) is used as the positive electrode active material, the protective film is positive. It can exist stably on the surface. Therefore, even when the nonaqueous electrolytic solution of the present invention is applied to a battery using a nickel-containing oxide as a positive electrode active material, the effect can be secured satisfactorily.

  There is no restriction | limiting in particular about the synthesis | combining method of the said sulfonate, What is necessary is just a method which can synthesize | combine the compound which has an ether bond and a sulfonic-acid metal base in 1 molecule. For example, a synthesis method by substitution reaction of a terminally brominated polyethylene glycol with sulfite, a synthesis method by reaction of polyethylene glycol and anhydrous sulfate, and the like can be mentioned.

  As a non-aqueous solvent (organic solvent) used for the non-aqueous electrolyte of the present invention, a high dielectric constant is preferable, and esters containing carbonates are more preferable. Among them, it is recommended to use an ester having a dielectric constant of 30 or more. Examples of such high dielectric constant esters include ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyrolactone, sulfur-based esters (such as ethylene glycol sulfite) and the like. Among these, cyclic esters are preferable, and cyclic carbonates such as ethylene carbonate, vinylene carbonate, propylene carbonate, and butylene carbonate are particularly preferable. In addition to the above various solvents, low-viscosity polar linear carbonates typified by dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, and the like, and aliphatic branched carbonate compounds can be used. A mixed solvent of a cyclic carbonate (particularly ethylene carbonate) and a chain carbonate is particularly preferred.

  In addition to the above non-aqueous solvents, chain alkyl esters such as methyl propionate; chain phosphate triesters such as trimethyl phosphate; nitrile solvents such as 3-methoxypropionitrile; dendrimers and dendrons A non-aqueous solvent (organic solvent) such as a branched compound having an ether bond can be used.

A fluorine-based solvent can also be used. Examples of the fluorine-based solvent include H (CF ₂ ) ₂ OCH ₃ , C ₄ F ₉ OCH ₃ , H (CF ₂ ) ₂ OCH ₂ CH ₃ , H (CF ₂ ) ₂ OCH ₂ CF ₃ , H (CF ₂ ) ₂ CH ₂ O (CF ₂ ) ₂ H or the like, or (perfluoroalkyl) alkyl ether having a linear structure such as CF ₃ CHFCF ₂ OCH ₃ , CF ₃ CHFCF ₂ OCH ₂ CH ₃ or iso (par Fluoroalkyl) alkyl ethers, that is, 2-trifluoromethyl hexafluoropropyl methyl ether, 2-trifluoromethyl hexafluoropropyl ethyl ether, 2-trifluoromethyl hexafluoropropylpropyl ether, 3-trifluorooctafluorobutyl methyl ether , 3-trifluorooctafluorobutyl ethyl ether, 3-trifluoroo Kutafluorobutylpropyl ether, 4-trifluorodecafluoropentyl methyl ether, 4-trifluorodecafluoropentyl ethyl ether, 4-trifluorodecafluoropentylpropyl ether, 5-trifluorododecafluorohexyl methyl ether, 5-trifluoro Dodecafluorohexyl ethyl ether, 5-trifluorododecafluorohexyl propyl ether, 6-trifluorotetradecafluoroheptyl methyl ether, 6-trifluorotetradecafluoroheptyl ethyl ether, 6-trifluorotetradecafluoroheptylpropyl ether, 7 -Trifluorohexadecafluorooctyl methyl ether, 7-trifluorohexadecafluorooctyl ethyl ether, 7-trifluorohexadecafluorohexyl octyl ether, etc. It is. Further, the iso (perfluoroalkyl) alkyl ether can be used in combination with the linear structure (perfluoroalkyl) alkyl ether.

Examples of the electrolyte salt used for the non-aqueous electrolyte of the present invention include alkali metal salts such as alkali metal perchlorates, organoboron alkali metal salts, alkali metal salts of fluorine-containing compounds, and alkali metal imide salts (for example, lithium salts). ) Is preferred. Specific examples of such an electrolyte salt include, for example, M ¹ ClO ₄ (M ¹ represents an alkali metal element such as Li, Na, K, and the like), M ¹ PF ₆ , M ¹ BF ₄ , M ¹ AsF ₆ , M ¹ SbF ₆ , M ¹ CF ₃ SO ₃ , M ¹ CF ₃ CO ₂ , M ¹ ₂ C ₂ F ₄ (SO ₃ ) ₂ , M ¹ N (CF ₃ SO ₂ ) ₂ , M ¹ N ( C ₂ F ₅ SO ₂ ) ₂ , M ¹ C (CF ₃ SO ₂ ) 3, M ¹ CnF _{2n + 1} SO ₃ (n ≧ 2), M ¹ N (RfOSO ₂ ) ₂ [where Rf is a fluoroalkyl group] A compound in which M ¹ in each of these compounds is a lithium element is more preferable, and a fluorine-containing organic lithium salt is particularly preferable. This is because the fluorine-containing organic lithium salt has a large anionic property and is easily ion-separated, so that it is easily dissolved in the non-aqueous electrolyte.

  The concentration of the electrolyte salt in the non-aqueous electrolyte is, for example, preferably 0.3 mol / l or more, more preferably 0.7 mol / l or more, preferably 1.7 mol / l or less, more preferably 1. 2 mol / l or less. If the electrolyte salt concentration is too low, the ionic conductivity may be reduced, and if it is too high, electrolyte salts that cannot be completely dissolved may be deposited.

  Moreover, you may add various additives which can improve the performance of the battery using this to the non-aqueous electrolyte of this invention.

For example, in a non-aqueous electrolyte solution to which a compound having a C═C unsaturated bond in the molecule is added, it may be possible to suppress a decrease in charge / discharge cycle characteristics of a battery using the non-aqueous electrolyte solution. Examples of the compound having such a C═C unsaturated bond in the molecule include aromatic compounds such as C ₆ H ₅ C ₆ H ₁₁ (cyclohexylbenzene); H (CF ₂ ) ₄ CH ₂ OOCCH═CH ₂ , Fluorinated aliphatic compounds such as F (CF ₂ ) ₈ CH ₂ CH ₂ OOCCH═CH ₂ ; fluorine-containing aromatic compounds; In addition, compounds having a sulfur element such as 1,3-propane sultone and 1,2-propanediol sulfate (for example, chain or cyclic sulfonate, chain or cyclic sulfate, etc.) and vinylene carbonate Vinyl ethylene carbonate, fluorinated ethylene carbonate, and the like can also be used and may be very effective. In particular, when a highly crystalline carbon material is used as the negative electrode active material, the combined use with vinylene carbonate, vinyl ethylene carbonate, fluorinated ethylene carbonate, or the like is more effective. The addition amount of these various additives is preferably 0.05 to 5% by mass in the total amount of the non-aqueous electrolyte.

  The vinylene carbonate, vinyl ethylene carbonate, and fluorinated ethylene carbonate form a protective film on the negative electrode surface by charging a battery using a non-aqueous electrolyte containing them, and the negative electrode active material and the non-aqueous electrolyte. Although it has the effect | action which suppresses the reaction by contact with electrolyte solution and prevents decomposition | disassembly of the non-aqueous electrolyte solution by such reaction, the electric potential which reacts with the sulfonate salt which concerns on this invention differs. Therefore, when the non-aqueous electrolyte contains the sulfonate and vinylene carbonate or vinyl ethylene carbonate, in the negative electrode, after the protective film derived from vinylene carbonate or vinyl ethylene carbonate is formed, the sulfonate Therefore, it is possible to prevent the deterioration of the quality of the protective film due to the mixture of the sulfonate-derived components in the protective film derived from vinylene carbonate or vinyl ethylene carbonate. Therefore, it is preferable that the non-aqueous electrolyte of the present invention contains vinylene carbonate or vinyl ethylene carbonate together with the sulfonate, and in a battery configured using such a non-aqueous electrolyte, the sulfonic acid is used. While securing the effect of the salt, the effect of vinylene carbonate or vinyl ethylene carbonate can be secured satisfactorily, and the battery can be further suppressed from swelling.

  In addition, an acid anhydride may be added to the non-aqueous electrolyte of the present invention in order to achieve improvement in the high temperature characteristics of the non-aqueous electrolyte secondary battery. The acid anhydride is involved in the formation of a composite film on the negative electrode surface as a surface modifier for the negative electrode, and has a function of further improving the storage characteristics of the battery at high temperatures. Moreover, since the amount of water in the non-aqueous electrolyte can be reduced by adding acid anhydride to the non-aqueous electrolyte, the amount of gas generated in the battery using this non-aqueous electrolyte is also reduced. be able to. There is no restriction | limiting in particular about the acid anhydride added to a nonaqueous electrolyte, What is necessary is just a compound which has at least one acid anhydride structure in a molecule | numerator, and the compound which has two or more may be sufficient as it. Specific examples of acid anhydrides include, for example, mellitic anhydride, malonic anhydride, maleic anhydride, butyric anhydride, propionic anhydride, puruvic anhydride, phthalonic anhydride, phthalic anhydride, pyromellitic anhydride, lactic acid anhydride, anhydrous Naphthalic acid, toluic anhydride, thiobenzoic anhydride, diphenic anhydride, citraconic anhydride, diglycolamide anhydride, acetic anhydride, succinic anhydride, cinnamic anhydride, glutaric anhydride, glutaconic anhydride, valeric anhydride, anhydrous Itaconic acid, isobutyric anhydride, isovaleric anhydride, benzoic anhydride and the like can be mentioned, and one or more of them can be used. Moreover, it is preferable that the addition amount of the acid anhydride in the non-aqueous electrolyte of the present invention is 0.05 to 1% by mass in the total amount of the non-aqueous electrolyte.

  The non-aqueous electrolyte secondary battery of the present invention only needs to have the non-aqueous electrolyte of the present invention, and there are no particular restrictions on other components, and it is the same as a conventionally known non-aqueous electrolyte secondary battery Can be used.

As the positive electrode active material related to the positive electrode, a compound capable of occluding and releasing lithium ions can be used. For example, Li _x MO ₂ or Li _y M ₂ O ₄ (where M is a transition metal, and 0 ≦ x ≦ 1, Examples thereof include lithium-containing composite oxides represented by 0 ≦ y ≦ 2), spinel-like oxides, and layered metal chalcogenides. Specific examples thereof include lithium cobalt oxides such as LiCoO ₂ , lithium manganese oxides such as LiMn ₂ O ₄ , lithium nickel oxides such as LiNiO _2, and lithium titanium oxides such as Li _4/3 Ti _5/3 O _4. , Metal oxides such as lithium manganese / nickel composite oxide, lithium manganese / nickel / cobalt composite oxide, manganese dioxide, vanadium pentoxide, chromium oxide; metal sulfides such as titanium disulfide and molybdenum disulfide; Etc.

In particular, a lithium-containing composite oxide having a layered structure or a spinel structure is preferably used, and lithium manganese / nickel composite oxide represented by LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiNi _1/2 Mn _1/2 O _2, etc. LiNi _1/3 Mn _1/3 Co _1/3 O ₂ , LiNi _0.6 Mn _0.2 Co _0.2 O ₂ typified lithium manganese / nickel / cobalt composite oxide, or LiNi _{1− x-y-z Co x Al} y Mg z O 2 ( however, 0 ≦ x ≦ 1,0 ≦ y ≦ 0.1,0 ≦ z ≦ 0.1,0 ≦ 1-x-y-z ≦ 1) The open circuit voltage during charging is 4 V or more on the basis of Li, such as a lithium-containing composite oxide in which some of the constituent elements are substituted with an additive element selected from Ge, Ti, Zr, Mg, Al, Mo, Sn, etc. Indicate When a lithium composite oxide is used as a positive electrode active material, it is possible to take advantage of the characteristics of the nonaqueous electrolyte solution of the present invention in which oxidation under high voltage is suppressed, and a high energy density nonaqueous electrolyte secondary battery. Is obtained.

  These positive electrode active materials may be used individually by 1 type, and may use 2 or more types together. For example, by using both a lithium-containing composite oxide having a layered structure and a lithium-containing composite oxide having a spinel structure, it is possible to achieve both higher capacity and improved safety.

  For the positive electrode for constituting the non-aqueous electrolyte secondary battery, for example, a conductive assistant such as carbon black and acetylene black, a binder such as polyvinylidene fluoride and polyethylene oxide, etc. are appropriately added to the positive electrode active material. A positive electrode material mixture is prepared by adding it, and a product obtained by finishing this into a strip-shaped molded body using a current collecting material made of aluminum foil or the like as a core material is used. However, the method for manufacturing the positive electrode is not limited to the above-described examples.

  As the negative electrode active material in the negative electrode for constituting the organic electrolyte secondary battery of the present invention, for example, a compound capable of occluding and releasing lithium ions can be used. For example, in addition to a simple lithium metal, an alloy such as Al, Si, Sn, In, or various materials such as an oxide and a carbon material that can be charged and discharged at a low potential close to lithium (Li) can be used as the negative electrode active material. . In the non-aqueous electrolyte secondary battery of the present invention, the negative electrode active material is particularly preferably a carbon material capable of electrochemically taking in and out lithium ions. Examples of such carbon materials include graphite, pyrolytic carbons, cokes, glassy carbons, fired bodies of organic polymer compounds, mesocarbon microbeads, carbon fibers, activated carbon, and the like.

When using a carbon material as the negative electrode active material, with respect to the interlayer distance _{d 002} of (002) plane the carbon material, it is preferably not more than 0.37 nm. In order to realize a high capacity of the battery, d ₀₀₂ is more preferably 0.35 nm or less, and further preferably 0.34 nm or less. The lower limit value of d ₀₀₂ is not particularly limited, but is theoretically about 0.335 nm.

  Further, the crystallite size Lc in the c-axis direction of the carbon material is preferably 3 nm or more, more preferably 8 nm or more, and further preferably 25 nm or more. The upper limit of Lc is not particularly limited, but is usually about 200 nm. And the average particle diameter becomes like this. Preferably it is 3 micrometers or more, More preferably, it is 5 micrometers or more, Preferably it is 15 micrometers or less, More preferably, it is 13 micrometers or less. Further, the purity is desirably 99.9% or more.

  For the negative electrode, for example, a conductive additive (carbon black, acetylene black, etc.) or a binder (polyvinylidene fluoride, styrene butadiene rubber, etc.) or the like is appropriately added to the negative electrode active material, or the negative electrode active material, as necessary. The prepared negative electrode mixture is produced by finishing a molded body using a current collecting material such as copper foil as a core material. However, the manufacturing method of the negative electrode is not limited to the above-described examples.

  In the nonaqueous electrolyte secondary battery of the present invention, the separator for partitioning the positive electrode and the negative electrode is not particularly limited, and various separators employed in conventionally known nonaqueous electrolyte secondary batteries can be used. For example, a microporous separator composed of a polyolefin resin such as polyethylene or polypropylene and a microporous separator composed of a polyester resin such as polybutylene terephthalate are preferably used. The thickness of the separator is not particularly limited, but is preferably 5 μm or more and 30 μm or less in consideration of both the safety of the battery and the increase in capacity.

  The non-aqueous electrolyte secondary battery of the present invention includes, for example, the above-described positive electrode and the above-described negative electrode overlapped with the separator interposed therebetween to form an electrode laminate, After that, the outer body is loaded, the positive and negative electrodes and the positive and negative terminals of the outer body are connected via a lead body, etc., and the nonaqueous electrolyte of the present invention is injected into the outer body, and then the outer body is sealed. Produced.

  As a battery outer package, a metal rectangular or cylindrical outer package, a laminate outer package made of a metal (such as aluminum) laminate film, or the like can be used.

Note that the manufacturing method of the non-aqueous electrolyte secondary battery and the structure of the battery are not particularly limited. However, when a carbon material having d ₀₀₂ of 0.34 nm or less is used as the negative electrode active material, a positive electrode, a negative electrode, a separator, It is preferable to provide an open chemical conversion step for charging after housing the water electrolyte and before completely sealing the battery. Thereby, the gas generated at the initial stage of charging and the residual moisture in the battery can be removed outside the battery. After the formation, the method for removing the gas in the battery is not particularly limited, and either natural removal or vacuum removal may be used. Further, before the battery is completely sealed, the battery may be appropriately molded by pressing or the like.

  The non-aqueous electrolyte secondary battery of the present invention is excellent in safety and has good battery characteristics. Therefore, taking advantage of these characteristics, the non-aqueous electrolyte secondary battery can be used as a driving power source for mobile information devices such as mobile phones and laptop computers. It can be widely used not only as a secondary battery but also as a power source for various devices.

  Hereinafter, the present invention will be described in detail based on examples. However, the following examples do not limit the present invention.

Example 1
<Synthesis of sulfonate A>
A sulfonate A represented by the following formula (6) and corresponding to n = 8 (n is an average addition number of oxyethylene units) was synthesized.

  In order to dissolve 100 g of polyethylene glycol (Sigma Aldrich, average molecular weight Mn = 400, 0.25 mol, hereinafter referred to as “PEG400”) in 400 mL of toluene and remove a trace amount of water, Was removed by distillation. The solution was allowed to cool to 35 ° C., 100 g of anhydrous triethylamine (Sigma Aldrich, approximately 1.0 mol) was added thereto, and the mixture was stirred at 35 ° C. for 1 hour. With further stirring, 165 g of thionyl bromide (Sigma Aldrich, 0.8 mol) dissolved in 400 mL of dehydrated toluene was slowly added dropwise to this solution at 35 ° C. and reacted for 1 day, and then refluxed for 2 hours. . All the above operations were performed in a dry argon atmosphere.

  The precipitate (triethylammonium bromide) is removed by filtration from the solution after reflux (brown solution) until the temperature drops, and the resulting reaction solution is incubated at room temperature for 4 hours and then heated to 50 ° C. Then, it was treated with 50 g of activated carbon (“GR” manufactured by Merck). Thereafter, the reaction solution was filtered with a glass filter, and the resulting bromide of PEG400 (hereinafter referred to as “Br-PEG400-Br”) as a product in hot toluene was extracted from the resulting precipitate by a Soxhlet extractor. And eluted repeatedly. The Br-PEG400-Br eluate was allowed to stand at 4 ° C. overnight, and the precipitated crystals were collected by filtration. The crystals were dissolved in 400 mL of absolute ethanol at 60 ° C., and treated with 20 g of activated carbon. did. The solution obtained by removing activated carbon from the treatment solution was cooled to 4 ° C. and left overnight to be recrystallized. Further, the crystal was washed with cold ethanol and cold ether and vacuum-dried to obtain about 81 g of yellow crystal (Br-PEG400-Br).

  The above-mentioned Br-PEG400-Br: 29 g (about 0.05 mol) was dissolved in 150 mL of ethanol, and 100 mL of 1 M lithium sulfite aqueous solution (lithium sulfite: 0.1 mol) was added thereto, and the mixture was stirred for 2 days. The reaction was carried out at reflux. Thereafter, water and ethanol were removed from the reaction solution, 100 mL of ethanol was added to the obtained reaction product and filtered, and the obtained filtrate was concentrated by evaporation to obtain a crude product. This was purified by gel filtration chromatography using methanol as an eluent to obtain 24 g of sulfonate A.

<Preparation of non-aqueous electrolyte>
In a solvent mixture of ethylene carbonate (EC), methyl ethyl carbonate (MEC), and diethyl carbonate (DEC) in a volume ratio of 1: 1: 2, LiPF ₆ was dissolved at 1.0 mol / L. Was added so that it might become 1.0 mass%, and the nonaqueous electrolyte solution was prepared. The non-aqueous electrolyte was prepared in an Ar atmosphere.

<Preparation of positive electrode>
The mixture was added to 95 parts by mass of Li _x Ni _1/3 Mn _1/3 Co _1/3 O ₂ (positive electrode active material), which is a layered MnNi material, and 2.5 parts by mass of carbon black as a conductive additive. A solution in which 2.5 parts by mass of polyvinylidene fluoride (PVDF) was dissolved in N-methyl-2-pyrrolidone (NMP) was added to and mixed to prepare a positive electrode mixture-containing slurry. This positive electrode mixture-containing slurry is passed through a 70-mesh net to remove large particles, and the positive electrode mixture-containing slurry is uniformly applied to both surfaces of a positive electrode current collector made of an aluminum foil having a thickness of 15 μm. Then, it was compression-molded by a roll press machine to a total thickness of 129 μm and then cut, and an aluminum lead body was welded to obtain a belt-like positive electrode.

<Production of negative electrode>
Mesophase carbon microbeads (MCMB) were used as the negative electrode active material. To 96 parts by mass of MCMB, a solution in which 4 parts by mass of PVDF was dissolved in NMP was added and mixed, and further NMP was added and mixed to obtain a negative electrode mixture-containing paste. This negative electrode mixture-containing paste is uniformly applied to both sides of a negative electrode current collector made of a copper foil having a thickness of 8 μm, dried, and then compressed by a roll press machine to a total thickness of 141 μm and then cut. The lead body made of nickel was welded to obtain a strip-shaped negative electrode.

<Battery assembly>
The strip-shaped positive electrode and the strip-shaped negative electrode are overlapped via a microporous polyethylene separator (porosity: 41%) having a thickness of 20 μm, wound in a spiral shape, and then pressed so as to be flat. Thus, an electrode winding body having a flat winding structure was formed, and the electrode winding body was fixed with an insulating tape made of polypropylene. Next, the electrode winding body is inserted into a rectangular battery case made of aluminum alloy having an outer dimension of 4.6 mm (length), 34 mm (width), and 43 mm (height), and the lead body is welded. The lid plate was welded to the open end of the battery case. Thereafter, the non-aqueous electrolyte solution was injected from the electrolyte solution injection port provided on the cover plate, and was allowed to stand for 1 hour. In addition, the design electric capacity at the time of charging to 4.35V of the nonaqueous electrolyte secondary battery of a present Example (4.45V on the basis of Li) was 800 mAh. Incidentally, the design electric capacity of the non-aqueous electrolyte secondary battery of this example when charged to 4.2 V (4.3 V based on Li) was about 700 mAh.

  Next, the battery was charged in a dry room with a dew point of −30 ° C. under the following conditions. Charging was performed for 1 hour at a constant current of 0.25 CmA (200 mA) so that the amount of charge was 25% (200 mAh) of the designed electric capacity (800 mAh) of the battery. After charging, the electrolyte injection port was sealed to seal the inside of the battery. The produced battery was charged at 0.3 CmA (240 mA) to 4.1 V and then stored at 60 ° C. for 12 hours. After that, the battery is charged at 0.3 CmA (240 mA) to 4.35 V, then charged at a constant voltage of 4.35 V for 3 hours, discharged to 3.8 V at 1 CmA (800 mA), and the charge voltage is 4 A battery for evaluation for evaluation as .35V was obtained.

  In addition, with respect to a battery different from the evaluation battery at the charging voltage of 4.35 V, the maximum charging voltage is changed from 4.35 V to 4.2 V, so that it becomes 25% of the battery design electric capacity described above. Then, a series of operations from charging for 1 hour at a constant current of 0.25 CmA to discharging to 3.8 V at 1 CmA was performed, and an evaluation battery for evaluating the charging voltage as 4.2 V was obtained.

  The structure of the nonaqueous electrolyte secondary battery of the present example obtained as described above is shown in FIGS. FIG. 1 is a perspective view showing the appearance of the nonaqueous electrolyte secondary battery of this example, and FIG. 2 is a schematic cross-sectional view taken along the line II of FIG.

  The non-aqueous electrolyte secondary battery 1 of the present embodiment is in a sealed space formed by an aluminum alloy battery case 2 and an aluminum alloy lid plate 3 welded to the opening end of the battery case 2. In addition, an electrode winding body 9 including a positive electrode 6, a negative electrode 7, and a separator 8, and a nonaqueous electrolytic solution (not shown) are accommodated. Terminals 5 are attached to the cover plate 3 via insulating packings 4. A lead plate 14 is attached to the bottom of the terminal 5, and the lead body 14 and the negative electrode 7 of the electrode winding body 9 are connected via a negative electrode lead body 12. The positive electrode 6 of the electrode winding body 9 is connected to the lid plate 3 via the positive electrode lead body 11. Reference numeral 10 denotes an insulator for partitioning the electrode winding body 9 and the battery case 2, and 13 is an insulator for partitioning the lid plate 3 and the lead plate 14.

Comparative Example 1
A non-aqueous electrolyte was prepared in the same manner as in Example 1 except that the sulfonate A was not added. The charge voltage was 4.35 V in the same manner as in Example 1 except that this non-aqueous electrolyte was used. The battery for evaluation and the battery for evaluation at a charging voltage of 4.2 V were prepared.

Comparative Example 2
A non-aqueous electrolyte was prepared in the same manner as in Example 1 except that 1,3-propane sultone was used in place of the sulfonate A, and the same as in Example 1 except that this non-aqueous electrolyte was used. Thus, an evaluation battery with a charging voltage of 4.35 V and an evaluation battery with a charging voltage of 4.2 V were produced.

Example 2
A sulfonate B represented by the above formula (6) and corresponding to n = 3 was synthesized. The synthesis of sulfonate B was performed in the same manner as the synthesis of sulfonate A in Example 1, except that polyethylene glycol (Fluka) having an average molecular weight Mn = 200 was used as a starting material.

  A non-aqueous electrolyte was prepared in the same manner as in Example 1 except that the sulfonate B was used in place of the sulfonate A, and the same as in Example 1 except that this non-aqueous electrolyte was used. Thus, an evaluation battery with a charging voltage of 4.35 V and an evaluation battery with a charging voltage of 4.2 V were produced.

Example 3
A sulfonate C represented by the above formula (6) and corresponding to n = 23 was synthesized. The synthesis of sulfonate C was carried out in the same manner as the synthesis of sulfonate A in Example 1 except that polyethylene glycol (Aldrich) having an average molecular weight Mn = 1050 was used as a starting material.

  A nonaqueous electrolytic solution was prepared in the same manner as in Example 1 except that the sulfonic acid salt C was used instead of the sulfonic acid salt A, and the same procedure as in Example 1 was performed except that this nonaqueous electrolytic solution was used. Thus, an evaluation battery with a charging voltage of 4.35 V and an evaluation battery with a charging voltage of 4.2 V were produced.

Example 4
A sulfonate D represented by the above formula (6) and corresponding to n = 50 was synthesized. The synthesis of sulfonate D was performed in the same manner as the synthesis of sulfonate A in Example 1 except that polyethylene glycol (Aldrich) having an average molecular weight Mn = 2200 was used as a starting material.

  A non-aqueous electrolyte was prepared in the same manner as in Example 1 except that the sulfonate D was used instead of the sulfonate A, and the same as in Example 1 except that this non-aqueous electrolyte was used. Thus, an evaluation battery with a charging voltage of 4.35 V and an evaluation battery with a charging voltage of 4.2 V were produced.

Example 5
A sulfonate E represented by the above formula (6) and corresponding to n = 100 was synthesized. The synthesis of the sulfonate E was performed in the same manner as the synthesis of the sulfonate A in Example 1 except that polyethylene glycol (Aldrich) having an average molecular weight Mn = 4400 to 4800 was used as a starting material.

  A non-aqueous electrolyte was prepared in the same manner as in Example 1 except that the sulfonate E was used instead of the sulfonate A, and the same as in Example 1 except that this non-aqueous electrolyte was used. Thus, an evaluation battery with a charging voltage of 4.35 V and an evaluation battery with a charging voltage of 4.2 V were produced.

  The following high temperature storage characteristic test was done about the non-aqueous electrolyte secondary battery of Examples 1-5 and Comparative Examples 1-2. The results are shown in Tables 1 and 2.

<High temperature storage characteristics test>
Among the batteries of Examples 1 to 5 and Comparative Examples 1 and 2, the battery for evaluation at a charging voltage of 4.35 V was charged to 4.35 V at 600 mA at 20 ° C., and further a constant voltage of 4.35 V The battery was fully charged by charging for 3 hours, and then discharged at 20 ° C. to 3 V at 0.2 C, and the discharge capacity before storage was measured.

Next, each battery was charged in the same manner as described above, and then stored in a thermostatic bath at 80 ° C. for 1 day. After each battery after storage was naturally cooled to 20 ° C., the thickness of the battery case was measured, and from the comparison with the thickness of the battery case before storage, the swelling of the battery was determined by the following formula. Thereafter, all the batteries were discharged at 20 ° C. to 3 V at 0.2 C, charged and discharged under the same conditions as before storage, and the discharge capacity after storage was measured.
Battery swelling (mm) = Battery thickness after storage-Battery thickness before storage

  Moreover, about each battery of Examples 1-5 and Comparative Examples 1-2, it charged until it became 4.2V at 700 mA at 20 degreeC about the battery for evaluation by the charge voltage 4.2V, and also 4.2V The battery was charged at a constant voltage for 2.5 hours to be fully charged, then discharged at 20 ° C. to 3 V at 0.2 C, and the discharge capacity before storage was measured.

  Next, each battery was charged in the same manner as described above, and then stored in a thermostatic bath at 80 ° C. for 1 day. Each battery after storage was naturally cooled to 20 ° C., and then the thickness of the battery case was measured. From the comparison with the thickness of the battery case before storage, the swelling of the battery was determined by the formula for calculating the swelling of the battery. Thereafter, all the batteries were discharged at 20 ° C. to 3 V at 0.2 C, charged and discharged under the same conditions as before storage, and the discharge capacity after storage was measured.

About each battery of Examples 1-5 and Comparative Examples 1-2, the capacity maintenance rate is calculated by the following formula using the discharge capacity before storage and the discharge capacity after storage, and the high temperature is calculated from the swelling of the battery and the capacity maintenance rate. Storage characteristics were evaluated.
Capacity maintenance rate (%) = (discharge capacity after storage / discharge capacity before storage) × 100

  As is clear from Table 1, in the nonaqueous electrolyte secondary battery of Example 1, battery swelling after storage was greatly suppressed as compared with the nonaqueous electrolyte secondary batteries of Comparative Example 1 and Comparative Example 2. Yes. Further, in the non-aqueous electrolyte secondary battery of Example 1, in particular, when the charging voltage was 4.35 V, which is a high voltage, compared with the non-aqueous electrolyte secondary batteries of Comparative Example 1 and Comparative Example 2, after storage The capacity is also maintained at a higher level. From these, it can be seen that the non-aqueous electrolyte secondary battery of Example 1 is excellent in high-temperature storage characteristics.

  Further, as is clear from Table 2, the nonaqueous electrolyte secondary batteries of Examples 2 to 5 have the same high-temperature storage characteristics as the nonaqueous electrolyte secondary battery of Example 1, and the sulfonic acid It can be seen that even when the salts B to E are used, the same effects as those obtained when the sulfonate A is used can be obtained.

Examples 6 to 13 and Comparative Example 3
<Preparation of non-aqueous electrolyte>
The amount of sulfonate A was 0.05% by mass (Example 6), 0.1% by mass (Example 7), 0.5% by mass (Example 8), 1% by mass (Example 9), 2% by mass (Example 10), 5% by mass (Example 11), 10% by mass (Example 12), 15% by mass (Example 13) and 0% by mass (Comparative Example 3), and further vinylene carbonate. The nonaqueous electrolytes of Examples 6 to 13 were prepared in the same manner as Example 1 except that 2.5% by mass was added.

<Production of non-aqueous electrolyte secondary battery>
The positive electrode active material was changed to a mixture of 10% by mass of Li _x Ni _1/3 Mn _1/3 Co _1/3 O ₂ and 85% by mass of LiCoAl _0.005 Mg _0.005 Zr _0.002 O ₂ A positive electrode was produced in the same manner as in Example 1 except that.

  Further, a negative electrode was produced in the same manner as in Example 1 except that the negative electrode active material was changed to highly crystalline artificial graphite obtained by the following method.

Coke powder 100 parts by weight, tar pitch 40 parts by weight, silicon carbide 14 parts by weight and coal tar 20 parts by weight are mixed in air at 200 ° C. and then pulverized, heat treated at 1000 ° C. in a nitrogen atmosphere, and further a nitrogen atmosphere Inside, it was heat-treated at 3000 ° C. and graphitized to produce artificial graphite. The obtained artificial graphite had a BET specific surface area of 4.0 m ² / g, a (002) plane spacing d ₀₀₂ of 0.336 nm measured by X-ray diffraction, and a crystallite size Lc in the c-axis direction. Was 48 nm and the total pore volume was 1 × 10 ⁻³ m ³ / kg.

  A nonaqueous electrolyte secondary battery for evaluation at a charging voltage of 4.35 V (Example 6), except that the positive electrode, the negative electrode, and the nonaqueous electrolytes were used. To 13 and Comparative Example 3 nonaqueous electrolyte secondary batteries). The design electric capacity (4.35 V) of these nonaqueous electrolyte secondary batteries was also 800 mAh.

  The non-aqueous electrolyte secondary batteries of Examples 6 to 13 and Comparative Example 3 were subjected to a high-temperature storage characteristic test in the same manner as the evaluation battery at the charging voltage of 4.35 V in Example 1, and battery swelling after storage was observed. evaluated. The results are shown in FIG.

  In addition, the following charge / discharge cycle test was performed on the nonaqueous electrolyte secondary batteries of Examples 6 to 13 and Comparative Example 3. These results are also shown in FIG.

<Charge / discharge cycle test>
Among the batteries of Examples 6 to 13 and Comparative Example 3, a battery different from that used in the high-temperature storage characteristic test was charged at 45 ° C. until it reached 4.35 V at 600 mA, and further 4.35 V. The battery was charged at a constant voltage of 3 hours for full charge, and then the charge / discharge cycle of discharging to 3 V at 1 mA of 800 mAh was repeated 300 times, and the discharge capacity at the first cycle and the discharge capacity at the 200th cycle were measured. Subsequently, using the discharge capacity at the first cycle and the discharge capacity at the 300th cycle, the capacity retention rate was calculated by the following formula, and the charge / discharge cycle characteristics were evaluated.
Capacity maintenance rate (%)
= (Discharge capacity at 300th cycle / Discharge capacity at 1st cycle) × 100

  Note that “addition amount (%)” on the horizontal axis in FIG. 3 means the addition amount (content) of the sulfonate A in the non-aqueous electrolyte used in each battery.

  As shown in FIG. 3, the non-aqueous electrolyte secondary batteries of Examples 6 to 13 are largely suppressed from swelling of the battery after storage, similarly to the non-aqueous electrolyte secondary batteries of Examples 1 to 5. It can be seen that it has excellent high-temperature storage characteristics. In addition, from the results of Examples 6 to 13, the amount of sulfonate in the nonaqueous electrolytic solution was 0.05% by mass or more, so that the battery without addition of sulfonate A (battery of Comparative Example 3) and It can also be seen that the effect is more effectively exhibited.

  In addition, as apparent from FIG. 3, when a non-aqueous electrolyte solution containing sulfonate A is used in a non-aqueous electrolyte secondary battery (Examples 6 to 13), sulfonate A is not contained. It can be seen that the capacity retention rate at the 300th cycle at 45 ° C. is high and the charge / discharge cycle characteristics are excellent as compared with the case where the nonaqueous electrolyte is used (Comparative Example 3). In addition, when the amount of sulfonate in the non-aqueous electrolyte was 10% by mass or more, it was found that the charge / discharge cycle characteristics at 45 ° C. were drastically decreased.

It is an external appearance perspective view which shows typically an example of the nonaqueous electrolyte secondary battery of this invention. FIG. 2 is a schematic cross-sectional view taken along the line II of FIG. 1. It is a graph which shows the result of the high temperature storage characteristic test of the nonaqueous electrolyte secondary battery of Examples 6-13 and the comparative example 3, and a charging / discharging cycle test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nonaqueous electrolyte secondary battery 2 Battery case 3 Cover plate 6 Positive electrode 7 Negative electrode 8 Separator 9 Electrode winding body

Claims (12)

A nonaqueous electrolytic solution comprising a nonaqueous solvent, an electrolyte salt, and a sulfonate represented by the general formula (1).

[Wherein, R ¹ and R ² are alkylene or phenylene having 1 to 6 carbon atoms in which hydrogen may be substituted with fluorine, and may be the same or different. M is an alkali metal element, m and n are integers of 0 to 100, and 1 ≦ m + n ≦ 100. X is hydrogen or a group represented by any of the following formulas (2) to (5). ]

[In the formulas (2) to (5), M ′ is an alkali metal element, and may be the same as or different from M in the formula (1). ]   2. The nonaqueous electrolytic solution according to claim 1, wherein, in the sulfonate represented by the general formula (1), the X is any group represented by the formulas (2) to (5).   The nonaqueous electrolytic solution according to claim 1 or 2, wherein in the sulfonate represented by the general formula (1), the X is a group represented by the formula (2). In the sulfonate represented by the general formula (1), R ¹ and R ² are alkylene having 1 to 6 carbon atoms, which may be the same or different, and m = 0. The nonaqueous electrolytic solution according to claim 3, wherein M is Li, X is a group represented by Formula (2), and M ′ is Li.   The nonaqueous electrolyte solution according to any one of claims 1 to 4, wherein a content of the sulfonate represented by the general formula (1) is 0.05 to 10% by mass in the total amount of the nonaqueous electrolyte solution.   The non-aqueous electrolyte according to claim 1, wherein the electrolyte salt is a lithium salt.   The nonaqueous electrolytic solution according to any one of claims 1 to 6, comprising a cyclic carbonate and a chain carbonate as the nonaqueous solvent.   The nonaqueous electrolytic solution according to claim 1, comprising vinylene carbonate, vinyl ethylene carbonate, or fluorinated ethylene carbonate.   A nonaqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, a separator, and the nonaqueous electrolyte solution according to claim 1. The non-aqueous electrolyte secondary battery according to claim 9, wherein the positive electrode contains a nickel-containing oxide as a positive electrode active material. A nonaqueous electrolyte secondary battery having a positive electrode, a negative electrode, a separator, and the nonaqueous electrolyte solution according to any one of claims 1 to 8 is charged, and the sulfonate in the nonaqueous electrolyte solution is reacted with the positive electrode. A method for producing a non-aqueous electrolyte secondary battery, comprising forming a film on a surface of a positive electrode. The method for producing a nonaqueous electrolyte secondary battery according to claim 11 , wherein the positive electrode contains a nickel-containing oxide as a positive electrode active material.

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