JP2014067700A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery excellent in all of cycle characteristics, storage characteristics, and continuous charging characteristics, even when used in conditions of severe temperatures and charge/discharge current equivalent or more than that of a conventional ones, such as in automobile applications.SOLUTION: The nonaqueous electrolyte secondary battery includes at least a positive electrode, a negative electrode, a nonaqueous electrolyte, and an outer packaging body, and at least one of the positive electrode, the negative electrode, the nonaqueous electrolyte, and the outer packaging body includes a basic compound.

Description

  The present invention relates to a non-aqueous electrolyte secondary battery.

  With the recent development of electronic technology and increasing interest in environmental technology, various electrochemical devices are used. In particular, there are many requests for energy saving, and expectations for what can contribute to it are increasing. Lithium ion secondary batteries, which are representative examples of power storage devices and are also representative examples of nonaqueous electrolyte secondary batteries, have been used mainly as charging places for portable devices, but in recent years, batteries for hybrid vehicles and electric vehicles have been used. The use as is expected.

  However, when a lithium ion secondary battery is used in an automotive application, the temperature and charge / discharge current conditions are more severe than those used for conventional portable devices. Therefore, in order to function well as a secondary battery even under such severe conditions, the lithium ion secondary battery is required to further improve cycle characteristics, storage characteristics, and continuous charge characteristics.

  Conventionally, techniques described in Patent Documents 1 and 2 have been proposed with the aim of improving these characteristics.

JP 2007-220335 A JP 2008-243810 A

  However, none of the conventional techniques including those described in Patent Documents 1 and 2 have been found yet to improve all of the cycle characteristics, storage characteristics, and continuous charge characteristics.

  Therefore, the present invention has been made in view of the above circumstances, and cycle characteristics, storage characteristics, and continuous characteristics even when used under severe temperature and charge / discharge current conditions equal to or higher than those of conventional automobiles and the like. It aims at providing the nonaqueous electrolyte secondary battery excellent in all the charging characteristics.

  As a result of intensive studies to solve the above problems, the present inventors have a positive electrode, a negative electrode, a non-aqueous electrolyte, an exterior body, and, in some cases, a separator, at least one of which is basic. It has been found that a non-aqueous electrolyte secondary battery containing a compound solves the above problems.

That is, the present invention is as follows.
[1]
A positive electrode, a negative electrode, a non-aqueous electrolyte, and an outer package,
A nonaqueous electrolyte secondary battery in which at least one of the positive electrode, the negative electrode, the nonaqueous electrolyte, and the outer package contains a basic compound.
[2]
The nonaqueous electrolyte secondary battery according to [1], wherein the base dissociation constant (pKb) of the anion contained in the basic compound is 10.83 or less.
[3]
The anion contained in the basic compound is at least one selected from the group consisting of PO ₄ ³⁻ , HPO ₄ ²⁻ , CO ₃ ²⁻ , HCO ₃ ⁻ , and SiO ₃ ^2−. Or the nonaqueous electrolyte secondary battery as described in [2].
[4]
The nonaqueous electrolyte according to any one of [1] to [3], wherein the anion contained in the basic compound is at least one selected from the group consisting of PO ₄ ³⁻ and HPO ₄ ^2−. Secondary battery.
[5]
The cation contained in the basic compound is at least one selected from the group consisting of Na ⁺ , K ⁺ , Be ²⁺ , Mg ²⁺ , Ca ²⁺ , and Al ^3+. 4]. The nonaqueous electrolyte secondary battery according to any one of 4).
[6]
Any one of [1] to [5] above, wherein the basic compound is at least one selected from the group consisting of Na ₃ PO ₄ , K ₃ PO ₄ , Ca ₃ (PO ₄ ) ₂ , and AlPO ₄ . 2. The nonaqueous electrolyte secondary battery according to item 1.
[7]
The nonaqueous electrolyte secondary battery according to any one of [1] to [6], wherein an average particle size of the basic compound is 0.1 to 100 μm.
[8]
The nonaqueous electrolyte secondary battery according to any one of [1] to [7], wherein an average particle size of the basic compound is 10 to 50 μm.
[9]
The non-aqueous electrolyte secondary battery according to any one of [1] to [8], wherein the positive electrode includes a positive electrode active material, and the specific surface area of the positive electrode active material is 0.6 m ² / g or more. .
[10]
The non-aqueous electrolyte secondary battery according to any one of [1] to [9], wherein the positive electrode active material includes a lithium transition metal oxide containing manganese.
[11]
The non-aqueous electrolyte secondary battery according to [9] or [10], wherein the basic compound is contained in an amount of 0.1 to 10% by mass with respect to the amount of the positive electrode active material.
[12]
The nonaqueous electrolyte secondary battery according to any one of [9] to [11], wherein the positive electrode active material has a potential of 4.5 V or more based on lithium.
[13]
The positive electrode active material has the following general formula (1):
Li _x Mn _{2- y My} O _z (1)
(In the formula, M represents at least one element selected from the group consisting of transition metal elements, and 0 <x ≦ 1.3, 0.2 <y <0.8, 3.5 <z <4. 5)
The nonaqueous electrolyte secondary battery according to any one of [9] to [12] above, comprising an oxide represented by:
[14]
The nonaqueous electrolyte secondary battery according to any one of [1] to [13], wherein the nonaqueous electrolyte includes lithium hexafluorophosphate.
[15]
The nonaqueous electrolyte secondary battery according to [14], wherein the basic compound is contained in an amount of 0.001 to 10 mol% with respect to lithium hexafluorophosphate contained in the nonaqueous electrolyte.
[16]
The nonaqueous electrolyte secondary battery according to any one of [1] to [15], wherein the outer package is a square type and / or a laminate type.
[17]
The nonaqueous electrolyte secondary battery according to any one of [1] to [16], wherein the nonaqueous solvent contained in the nonaqueous electrolyte does not contain an F element.

  According to the present invention, a non-aqueous electrolyte secondary excellent in all of cycle characteristics, storage characteristics and continuous charge characteristics even when used under severe temperature and charge / discharge current conditions equal to or higher than those of conventional applications, such as automobile applications. A battery can be provided.

  Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be implemented with appropriate modifications within the scope of the gist thereof.

[Nonaqueous electrolyte secondary battery]
The nonaqueous electrolyte secondary battery of the present embodiment includes at least a positive electrode, a negative electrode, a nonaqueous electrolyte, and an exterior body, and at least one of the positive electrode, the negative electrode, the nonaqueous electrolyte, and the exterior body is included. Contains basic compounds. The nonaqueous electrolyte secondary battery may further include a separator. Basic compounds include X-ray diffraction analysis (XRD), various nuclear magnetic resonance analyzes (Nuclear Magnetic Resonance; NMR), and, for example, fast atom bombardment-mass spectrometry (FAB-MS). Etc. can be confirmed by mass spectrometry. The content can be quantified by inductively coupled plasma-atomic emission spectrometry (ICP-AES).

[Basic compounds]
The basic compound used in the present embodiment can be used as long as it is a conventionally known compound showing basicity. The base dissociation constant (pKb) of the anion contained in the basic compound is preferably 10.83 or less, more preferably 7.65 or less, and still more preferably 2.00 or less. The lower limit of the base dissociation constant (pKb) of the anion is preferably 0.01 or more. When the base dissociation constant (pKb) of the anion is within the above range, the cycle characteristics, the storage characteristics and the continuous charge characteristics tend to be more excellent even when used under severe temperature and charge / discharge current conditions. In the examples of the present invention, pKb was calculated according to the following equation instead of measurement.
pKb = 14−pKa

  pKa is an acid dissociation constant, and pKb was calculated by substituting the value of the conjugate acid with respect to the anion for pKa. The value of pKa for determining the pKb of the basic compound used in the examples of the present invention was cited from the document “Maruzen Chemical Handbook”. Moreover, when calculating | requiring the pKb value of the basic compound which is not described in well-known literature, it can calculate | require by the method of utilizing the neutralization reaction of an acid base, for example. It can be obtained by titrating a basic compound with an appropriate acid standard solution such as hydrochloric acid or an aqueous oxalic acid solution and analyzing the titration curve. The titration may be performed using a pH indicator or a commercially available pH measuring device. Measurement conditions are usually carried out in an aqueous solution at normal pressure (1 atm) and 25 ° C.

The anion of the basic compound is not particularly limited. For example, PO ₄ ³⁻ , HPO ₄ ²⁻ , H ₂ BO ₃ ⁻ , CO ₃ ²⁻ , HCO ₃ ⁻ , SiO ₃ ²⁻ , AsO ₂ ⁻ , AsO ₃ ³⁻ , HAsO ₃ ²⁻ , H ₂ AsO ₃ ⁻ , AsO ₄ ³⁻ , HAsO ₄ ²⁻ , BrO ⁻ , CN ⁻ , CNO ⁻ , IO ⁻ , BrO ⁻ , ClO ⁻ , MoO ₄ ²⁻ , HMoO ₄ ⁻ , N ₃ ⁻ , N ₂ O ₂ ²⁻ , HN ₂ O ₂ ⁻ , SCN ⁻ , NO ₂ ⁻ , HPO ₃ ²⁻ , H ₂ P ₂ O ₇ ²⁻ , H ₃ P ₂ O ₇ ⁻ , H ₃ P ₃ O ₁₀ ²⁻ , H ₄ PO ₃ O ₁₀ ⁻ , S ²⁻ , HS ⁻ , SO ₃ ²⁻ , Se ²⁻ , SeO ₃ ²⁻ , SiO ₂ (OH) ₂ ²⁻ , HSiO ₂ (OH) ₂ ⁻ , TeO ₃ ²⁻ , TeO ₄ ²⁻ , HTeO ₄ ⁻ , VO ₄ ³⁻ , HVO ₄ ²⁻ , H ₂ VO ₄ ⁻ , WO ₄ ²⁻ , HWO ₄ ⁻ , AgO ⁻ , H ₂ AlO ₃ ^{− _{, CrO 4 -, GeO 3 2-}} , HGeO 3 -, ^{_{bO 2 -, Te -, H}} 2 AuO 3 -, and H ₂ GaO ₃ ^- preferable to be one or more selected from the group consisting ^{_{of, PO 4 3-, HPO 4 2-}} , CO 3 2-, HCO 3 ^- and more preferable to be one or more selected from the group consisting of SiO ₃ ^2-, further preferably a PO ₄ ^3- and HPO ₄ one or more members selected from the group consisting ^{of 2.} By using such a basic compound containing an anion, even when used under severe temperature and charge / discharge current conditions, cycle characteristics, storage characteristics and continuous charge characteristics tend to be more excellent. When these anions are contained in the nonaqueous electrolyte, they can be confirmed and quantified by ion chromatography analysis (Ion Chromatography; IC). When it is contained other than the non-aqueous electrolyte, a scanning electron microscope-energy dispersive X-ray analysis (Scanning Electron Microscope-Energy Dispersive X-ray spectroscopy; SEM-EDX), for example, Raman spectroscopy or infrared spectroscopy (Infrared spectroscopy) The presence can be confirmed by spectroscopic analysis such as IR) and mass spectrometry such as FAB-MS. The content can be quantified by ICP-AES.

  The anion contained in the basic compound is not limited to the inorganic anion as described above, and may be an anion having a base dissociation constant (pKb) of 10.83 or less, and may be an organic anion.

The cation of the basic compound is not particularly limited, and examples thereof include alkali metals such as Li ⁺ , Na ⁺ , and K ⁺ , and alkaline earth metals such as Be ²⁺ , Mg ^2+, and Ca ²⁺ , 1 or more types chosen from the group which consists of ^{Al3 +} etc. are mentioned. Among these, at least one selected from the group consisting of alkali metals such as Na ⁺ and K ⁺ , alkaline earth metals such as Be ²⁺ , Mg ²⁺ and Ca ^2+, and Al ³⁺ is preferable. . Further, one or more selected from the group consisting of alkali metals such as Na ⁺ and K ⁺ and alkaline earth metals such as Be ²⁺ , Mg ²⁺ and Ca ²⁺ are more preferable. By using a basic compound having a cation composed of an alkali metal such as Na ⁺ and K ⁺ and an alkaline earth metal such as Be ²⁺ , Mg ²⁺ and Ca ²⁺ , severe temperature and charge / discharge current Even when used under the above conditions, the cycle characteristics, storage characteristics and continuous charge characteristics tend to be more excellent. When these cations are contained in the nonaqueous electrolyte, they can be confirmed and quantified by IC. When it is contained other than the non-aqueous electrolyte, its presence can be confirmed by SEM-EDX, for example, Raman spectroscopic analysis, spectroscopic analysis such as IR, and mass spectrometric analysis such as FAB-MS. The content can be quantified by ICP-AES.

Such a basic compound is not particularly limited. For example, Li ₃ PO ₄ , Li ₂ CO ₃ , Na ₃ PO ₄ , Na ₂ CO ₃ , K ₃ PO ₄ , K ₂ CO ₃ , Ca ₃ (PO ₄ ) ₂ , CaCO ₃ , AlPO ₄ and Al ₂ (CO ₃ ) ₃ are preferred. By using such a basic compound, cycle characteristics, storage characteristics, and continuous charge characteristics tend to be more excellent even when used under severe temperature and charge / discharge current conditions. Among these, at least one selected from the group consisting of Na ₃ PO ₄ , K ₃ PO ₄ , Ca ₃ (PO ₄ ) ₂ and AlPO ₄ is preferable. Furthermore, at least one selected from the group consisting of Na ₃ PO ₄ , K ₃ PO ₄ and Ca ₃ (PO ₄ ) ₂ is more preferable. By using such a basic compound, it is more preferable from the viewpoint of not only cycle characteristics, storage characteristics and continuous charge characteristics, but also high-speed charge / discharge characteristics. The width of can also be expanded. Furthermore, there is an advantage that the cost can be reduced. When these basic compounds are contained in the nonaqueous electrolyte, they can be confirmed and quantified by IC. When it is contained other than the non-aqueous electrolyte, its presence can be confirmed by XRD, NMR, SEM-EDX, for example, Raman spectroscopic analysis, spectroscopic analysis such as IR, and mass spectrometry such as FAB-MS. The content can be quantified by ICP-AES.

  Although content of a basic compound is not specifically limited, When the positive electrode with which a nonaqueous electrolyte secondary battery is equipped contains a positive electrode active material, it is 0.1-200 mass% with respect to the positive electrode active material amount. Is more preferable, 0.1 to 10% by mass is more preferable, and 0.1 to 1% by mass is further preferable. When the content of the basic compound is within the above range, the cycle characteristics, storage characteristics, and continuous charge characteristics tend to be more excellent even when used under severe temperature and charge / discharge current conditions. In addition, the cost tends to be excellent.

  Moreover, 0.001-10 mol% is preferable with respect to the sum total of the lithium hexafluorophosphate contained in a non-aqueous electrolyte, and, as for content of a basic compound, 0.01-10 mol% is more preferable, 5 mol% is more preferable. When the basic compound content is within the above range, not only the cycle characteristics, storage characteristics and continuous charge characteristics, but also high-speed charge / discharge characteristics can be used even under severe temperature and charge / discharge current conditions. It tends to be better from the viewpoint.

  The basic compound is preferably solid. When the basic compound is solid particles, the size thereof is not particularly limited, but the average particle size is preferably 0.1 to 100 μm, and more preferably 10 to 50 μm. When the average particle size is 0.1 μm or more, the effect of the basic compound can be maintained for a long time, and excellent cycle characteristics, storage characteristics, and continuous charge / discharge characteristics can be improved over a long period of time. Further, when the average particle size is 100 μm or less, battery characteristics such as discharge characteristics can be favorably maintained. The average particle diameter can be measured by any known method. For example, the average particle diameter is measured by a laser diffraction particle size distribution measuring apparatus, and the median diameter (d50) in which the large particles and the small particles are equal is determined as the average particle diameter. Used as

[Positive electrode]
The positive electrode used in the present embodiment preferably includes a positive electrode active material, a conductive material, a binder, and a current collector.

[Positive electrode active material]
The positive electrode preferably includes a lithium transition metal oxide containing manganese as a positive electrode active material from the viewpoint of cost. Examples of such oxides include compounds represented by the following general formulas (1), (3), and (7). By using a lithium transition metal oxide containing manganese as a positive electrode active material, preferably a compound represented by the following general formulas (1), (3) and (7), it is used under severe temperature and charge / discharge current conditions. Even in such a case, cycle characteristics, storage characteristics, and continuous charge characteristics tend to be more excellent.

As the positive electrode active material that can be included in the positive electrode, a known material that can electrochemically occlude and release lithium ions can be used. Among these, as the positive electrode active material, a material containing lithium is preferable. Examples of the positive electrode active material include the following general formula (1):
Li _x Mn _{2- y My} O _z (1)
(In the formula, M represents at least one element selected from the group consisting of transition metal elements, and 0 <x ≦ 1.3, 0.2 <y <0.8, 3.5 <z <4. 5)
An oxide represented by the following general formula (2):
_{Li x M y O z (2} )
(In the formula, M represents at least one element selected from the group consisting of transition metal elements, and 0 <x ≦ 1.3, 0.8 <y <1.2, and 1.8 <z <2.2. .)
A layered oxide represented by the following general formula (3):
_{LiMn 2-x Ma x O 4} (3)
(In the formula, Ma represents at least one element selected from the group consisting of transition metal elements, and 0.2 ≦ x ≦ 0.7.)
A spinel oxide represented by the following general formula (4):
Li ₂ McO ₃ (4)
(In the formula, Mc represents at least one element selected from the group consisting of transition metal elements.)
An oxide represented by the following general formula (5):
LiMdO ₂ (5)
(In the formula, Md represents at least one element selected from the group consisting of transition metal elements.)
A composite oxide with an oxide represented by the following general formula (6):
_{zLi 2 McO 3 - (1-} z) LiMdO 2 (6)
(In the formula, Mc and Md are synonymous with those in the above formulas (4) and (5), respectively, and 0.1 ≦ z ≦ 0.9.)
Li-excess layered oxide positive electrode active material represented by the following general formula (7):
LiMb _1-y Fe _y PO ₄ (7)
(In the formula, Mb represents at least one element selected from the group consisting of Mn and Co, and 0 ≦ y ≦ 1.0.)
And an olivine-type positive electrode active material represented by the following general formula (8):
Li ₂ MePO ₄ F (8)
(Wherein, Me represents at least one element selected from the group consisting of transition metal elements). These positive electrode active materials are used alone or in combination of two or more.

The specific surface area of the positive electrode active material is preferably 0.1 m ² / g or more, and more preferably 0.6 m ² / g or more. Further, the specific surface area of the positive electrode active material is preferably 10.0 m ² / g or less. When the specific surface area of the positive electrode active material is 0.1 m ² / g or more, the side reaction of electrolyte decomposition that occurs on the surface of the positive electrode active material tends to proceed, and the accompanying hydrofluoric acid is more efficiently generated by the basic compound. It tends to be removed. Moreover, when the specific surface area of the positive electrode active material is 0.1 m ² / g or more, battery characteristics such as discharge characteristics tend to be more excellent. On the other hand, when the specific surface area of the positive electrode active material is 10.0 m ² / g or less, cycle characteristics and storage characteristics tend to be more excellent.

  Furthermore, in the present embodiment, the potential of the positive electrode active material is preferably 4.5 V or more on the basis of lithium. When the potential of the positive electrode active material is 4.5 V or more on the basis of lithium, the electrolyte is easily decomposed, but the accompanying hydrofluoric acid can be removed by the basic compound, which is more effective. Note that the potential of the positive electrode active material can be measured by the method described in Examples.

  As the conductive material that can be included in the positive electrode, a known material that can conduct electrons can be used. Among these, as the conductive material, non-graphitic carbonaceous materials such as activated carbon, various cokes, carbon black and acetylene black, and graphite are preferable. These are used singly or in combination of two or more.

  As the binder that can be included in the positive electrode, a known material that can bind at least two of the positive electrode active material, the conductive material that can be included in the positive electrode, and the current collector that can be included in the positive electrode can be used. Among these, as the binder, polyvinylidene fluoride and fluororubber are preferable. A binder is used individually by 1 type or in combination of 2 or more types.

  The current collector that can be included in the positive electrode is not particularly limited, and all conventionally known ones can be used, for example, metal foils such as aluminum, titanium, and stainless steel, expanded metal, punch metal, foam metal, carbon cloth, and Carbon paper is mentioned. These are used singly or in combination of two or more.

  When the basic compound used in the present embodiment is contained in the positive electrode, it can be used by mixing with at least one of the positive electrode active material, the conductive material, and the binder. Further, the basic compound may be coated on or partially adhered to at least one surface of the positive electrode active material, the conductive material, and the current collector. Furthermore, a basic compound may be coated on the surface of the electrode including the positive electrode active material, the conductive material, the binder, and the current collector. More specifically, for example, a support layer containing a basic compound and a polymer may be formed on the surface of the electrode to form a two-layer structure. The basic compound can be melted and used as a binder.

[Negative electrode]
The negative electrode used in the present embodiment preferably includes a negative electrode active material, a binder, and a current collector.

  As the negative electrode active material that can be contained in the negative electrode, a known material that can electrochemically occlude and release lithium ions can be used. Among these, as the negative electrode active material, for example, carbon materials such as graphite powder, mesophase carbon fiber, and mesophase microspheres, and metals, alloys, oxides, and nitrides are preferable. These are used singly or in combination of two or more.

  As the binder that can be included in the negative electrode, a known material that can bind at least two of the negative electrode active material, the conductive material that can be included in the negative electrode, and the current collector that can be included in the negative electrode can be used. Among these, carboxymethyl cellulose, styrene-butadiene crosslinked rubber latex, acrylic latex, and polyvinylidene fluoride are preferable as the binder. These are used singly or in combination of two or more.

  The current collector that can be included in the negative electrode is not particularly limited, and all conventionally known ones can be used, for example, metal foils such as copper, nickel, and stainless steel, expanded metal, punch metal, foam metal, carbon cloth, and And carbon paper. These are used singly or in combination of two or more.

  When the basic compound used in this embodiment is contained in the negative electrode, it can be used by mixing with at least one of the negative electrode active material and the binder. Further, the basic compound may be coated on or partially attached to at least one surface of the negative electrode active material and the current collector. Furthermore, a basic compound may be coated on the surface of the electrode including the negative electrode active material, the binder, and the current collector. More specifically, for example, a support layer containing a basic compound and a polymer may be formed on the surface of the electrode to form a two-layer structure. The basic compound can be melted and used as a binder.

[Non-aqueous electrolyte]
The electrolyte (salt) used for the non-aqueous electrolyte in the present embodiment is not particularly limited, and a conventionally known one can be used. The electrolyte is not particularly limited, for example, LiPF ₆ (lithium _{hexafluorophosphate), LiClO 4, LiAsF 6,} Li 2 SiF 6, LiOSO 2 C k F 2k + 1 [k is an integer of 1 to 8] LiN (SO ₂ C _k F _{2k + 1} ) ₂ [k is an integer of 1 to 8], LiPF _n (C _k F _{2k + 1} ) _6-n [n is an integer of 1 to 5, k is 1 to 8 Integer], LiPF ₄ (C ₂ O ₄ ), and LiPF ₂ (C ₂ O ₄ ) ₂ , LiBF ₄ , LiAlO ₄ , LiAlCl ₄ , Li ₂ B ₁₂ F _b H _12-b [b is 0 to 3 Integer], LiBF _q (C _s F _{2s + 1} ) _4-q [q is an integer of 1-3, s is an integer of 1-8], LiB (C ₂ O ₄ ) ₂ , LiBF ₂ (C ₂ O ₄ ), LiB (C ₃ O ₄ H ₂ ) ₂ , LiPF ₄ (C ₂ O ₂ ) and the like. These electrolytes are used singly or in combination of two or more. Of these, LiPF ₆ is preferred. By using such an electrolyte, cycle characteristics, storage characteristics, and continuous charge characteristics tend to be more excellent even when used under severe temperature and charge / discharge current conditions.

  The non-aqueous solvent used in the non-aqueous electrolyte in the present embodiment is not particularly limited, and a conventionally known one can be used. As the non-aqueous solvent, for example, an aprotic polar solvent is preferable. Specific examples thereof include ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, trifluoromethylethylene carbonate, fluoroethylene. Carbonates and cyclic carbonates such as 4,5-difluoroethylene carbonate; lactones such as γ-butyrolactone and γ-valerolactone; cyclic sulfones such as sulfolane; cyclic ethers such as tetrahydrofuran and dioxane; ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methylpropyl Carbonate, methyl isopropyl carbonate, dipropyl carbonate, methyl butyl carbonate, dibutyl carbonate, ethyl Examples include chain carbonates such as rupropyl carbonate and methyl trifluoroethyl carbonate; nitriles such as acetonitrile; chain ethers such as dimethyl ether; chain carboxylic acid esters such as methyl propionate; chain ether carbonate compounds such as dimethoxyethane. .

  Among these, the non-aqueous solvent is preferably a compound containing no F element. When the non-aqueous solvent does not contain the F element, there is a tendency that excessive hydrofluoric acid generation can be suppressed.

  These are used singly or in combination of two or more.

  Note that the nonaqueous electrolyte of the present embodiment may be a liquid or a solid electrolyte.

  When the basic compound used in the present embodiment is contained in the non-aqueous electrolyte, the basic compound can be mixed with a non-aqueous solvent and used. Moreover, it can be used even if it mixes a basic compound with a solid electrolyte.

〔separator〕
As a separator that can be used in the present embodiment, a conventionally known separator used for a nonaqueous electrolyte secondary battery can be used. As a separator, the microporous film of polyolefin resins, such as polyethylene and a polypropylene, used for the conventional nonaqueous electrolyte secondary battery is mentioned, for example. In addition, as a separator, for example, a non-woven fabric containing or coated with a resin such as cellulose, aromatic polyamide, fluororesin and polyolefin, and one kind of inorganic substance such as alumina and silica, or a mixture of two or more kinds, Structures such as papermaking and porous films, and solid electrolyte films can be mentioned. Any separator may be used as long as it has a high ion permeability and has a function of electrically isolating the positive electrode and the negative electrode.

  When the basic compound used in this embodiment is contained in the separator, the surface of the separator can be used by coating the basic compound. Moreover, a basic compound can also be mixed and used for a separator. Further, a basic compound may be sandwiched between a plurality of separators. Alternatively, the basic compound can be processed into a thin film and used as a separator.

[Exterior body]
A conventionally well-known thing can be used for the exterior body used for this embodiment. Examples of the material for the exterior body include metals such as stainless steel, iron, and aluminum, and a laminate film in which the surface of the metal is coated with a resin.

  The hydrofluoric acid generated by the decomposition of the electrolyte is finally converted into a gas such as hydrogen. Therefore, battery performance deterioration and safety reduction due to expansion of the outer package due to generation of hydrofluoric acid are cited as problems. According to the present embodiment, since the basic compound is included, the hydrofluoric acid generated by the decomposition of the electrolyte can react with the basic compound before being converted into gas. Thereby, generation | occurrence | production of the gas resulting from generation | occurrence | production of a hydrofluoric acid can be suppressed. Therefore, when a laminate film or a metal square shape that is easily affected by expansion is used as the exterior body, the effect of suppressing expansion of the battery exterior body due to suppression of gas generation is particularly effective, which is preferable.

  When the basic compound used in the present embodiment is included in the outer package, the basic compound is coated on the outer package, or the material used for the outer package is mixed with the basic compound. Can be used.

  The non-aqueous electrolyte secondary battery of the present embodiment may have the same configuration as a conventionally known one except that it has the above-described configuration. Examples of the nonaqueous electrolyte secondary battery of the present embodiment include a lithium ion secondary battery and a lithium ion capacitor. Moreover, the manufacturing method of the nonaqueous electrolyte secondary battery of this embodiment may be the same as the manufacturing method of the conventional nonaqueous electrolyte secondary battery except that the basic compound is contained as described above.

  The non-aqueous electrolyte secondary battery of this embodiment has all of cycle characteristics, storage characteristics, and continuous charge characteristics even when used under severe temperature and charge / discharge current conditions equal to or higher than those of conventional applications such as automobile applications. It will be excellent.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

<Example 1>
<Synthesis of positive electrode active material>
・ Synthesis of LiNi _0.5 Mn _1.5 O _{4 with} a nitrogen adsorption specific surface area of 0.6 m ² / g. A molar ratio of transition metal elements of nickel sulfate and manganese sulfate in a ratio of 1: 3 was dissolved in water, and the metal ion concentration A nickel-manganese mixed aqueous solution was prepared so that the total was 2 mol / L. Subsequently, this nickel-manganese mixed aqueous solution was dropped into 3000 mL of a 2 mol / L sodium carbonate aqueous solution heated to 70 ° C. at an addition rate of 12.5 mL / min for 120 minutes. At the time of dropping, air with a flow rate of 200 mL / min was blown into the aqueous solution while stirring. As a result, a precipitated substance was generated, and the obtained precipitated substance was sufficiently washed with distilled water and dried to obtain a nickel manganese compound. The obtained nickel-manganese compound and lithium carbonate having a particle size of 2 μm were weighed so that the molar ratio of lithium: nickel: manganese was 1: 0.5: 1.5, and obtained after dry-mixing for 1 hour. The obtained mixture was fired at 1000 ° C. for 5 hours in an oxygen atmosphere to obtain a positive electrode active material represented by LiNi _0.5 Mn _1.5 O ₄ . The specific surface area was measured with nitrogen using an autosorb-1 manufactured by Cantachrome Co., Ltd. and calculated by the BET method. The nitrogen adsorption specific surface area of the obtained LiNi _0.5 Mn _1.5 O ₄ active material was 0.6 m ² / g. Moreover, in order to regulate the potential of the positive electrode active material, a nonaqueous electrolyte secondary battery was prepared by the method shown below except that metal Li was used for the negative electrode, and a constant temperature bath (Futaba Kagakusha) set at 25 ° C. Made in a thermostatic chamber PLM-73S) and connected to a charge / discharge device (manufactured by Asuka Electronics Co., Ltd., charge / discharge device ACD-01). Next, when the potential difference between LiNi _0.5 Mn _1.5 O ₄ and Li was measured in a fully charged state, it was 4.9 V.

<Preparation of positive electrode>
The positive electrode active material obtained as described above, graphite powder (manufactured by TIMCAL, KS-6) and acetylene black powder (manufactured by Denki Kagaku Kogyo, HS-100) as a conductive assistant, and polyfluoride as a binder. A vinylidene chloride solution (manufactured by Kureha, L # 7208) was mixed at a mass ratio of 80: 5: 5: 10 in terms of solid content. The resulting mixture was further mixed with Li ₃ PO ₄ , which is solid particles having an average particle size of 30 μm, so as to be 1.0 mass% with respect to the amount of the positive electrode active material. To the obtained mixture, N-methyl-2-pyrrolidone as a dispersion solvent was added so as to have a solid content of 35% by mass and further mixed to prepare a slurry solution. This slurry-like solution was applied to one side of an aluminum foil having a thickness of 20 μm, and the solvent was dried and removed, followed by rolling with a roll press. The rolled product was punched into a disk shape having a diameter of 16 mm to obtain a positive electrode.

<Production of negative electrode>
Graphite powder (OMAC1.2H / SS, manufactured by Osaka Gas Chemical Co., Ltd.) and graphite powder (TIMCAL, SFG6) as a negative electrode active material, and styrene-butadiene rubber (SBR) and an aqueous carboxymethylcellulose solution as a binder, 90:10: Mixed at a solids weight ratio of 1.5: 1.8. The obtained mixture was added to water as a dispersion solvent so that the solid content concentration was 45% by mass to prepare a slurry-like solution. This slurry-like solution was applied to one side of a copper foil having a thickness of 18 μm, and the solvent was removed by drying, followed by rolling with a roll press. The rolled product was punched into a disk shape having a diameter of 16 mm to obtain a negative electrode.

<Preparation of non-aqueous electrolyte>
LiPF ₆ was dissolved in a mixed solvent in which ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed at a volume ratio of 1: 2 so as to be 1 mol / L to obtain an electrolyte solution which is a nonaqueous electrolyte. .

<Production of battery>
A laminate in which the positive electrode and the negative electrode produced as described above are superimposed on both sides of a separator (thickness 25 μm, porosity 50%, pore diameter 0.1 μm to 1 μm) made of a polypropylene microporous film is made of stainless steel. It was inserted into a disc-shaped battery case (exterior body) made by the manufacturer. Next, 0.5 mL of the above electrolytic solution was injected therein, and the laminate was immersed in the electrolytic solution, and then the battery case was sealed to produce a nonaqueous electrolyte secondary battery.

The porosity of the separator and the microporous membrane (hereinafter referred to as “separator etc.”) was determined as follows. First, the weight per unit area W (g / cm ² ) and the average density ρ (g / cm ³ ) of each component constituting the separator were calculated from the mass of a sample such as a 100 mm square separator. From these and the thickness d (cm) of the separator or the like, the following formula:
Porosity = (W / (d × ρ)) × 100 (%)
From this, the porosity was derived.

Moreover, the hole diameter of a separator etc. was calculated | required as follows. It is known that the fluid inside the capillary follows a Knudsen flow when the mean free path of the fluid is larger than the capillary pore diameter, and a Poiseuille flow when it is small. Therefore, it was assumed that the air flow in the air permeability measurement of the separator or the like follows the Knudsen flow, and the water flow in the water permeability measurement of the separator or the like follows the Poiseuille flow. The average pore diameter D (μm) and the curvature T (dimensionless) are determined based on the air permeation rate constant R _gas (m ³ / (m ² · sec · Pa)) and the water permeation rate constant R _liq (m ³ / ( m ² · sec · Pa)), air molecular velocity ν (m / sec), water viscosity η (Pa · sec), standard pressure Ps (= 101325 Pa), separator ε porosity (%) and membrane It calculated | required from the thickness L (micrometer) using the following formula.
D = 2ν × (R _liq / R _gas ) × (16η / 3Ps) × 10 ⁶
T = (D × (ε / 100) × ν / (3L × Ps × R _gas )) ^1/2
Here, R _gas was calculated | required from the air permeability (sec) of air using the following formula.
R _gas = 0.0001 / (air permeability × (6.424 × 10 ⁻⁴ ) × (0.01276 × 101325))
R _liq was determined from the water permeability (cm ³ / (cm ² · sec · Pa)) using the following formula.
R _liq = water permeability / 100
The water permeability was determined as follows. A separator or the like previously immersed in alcohol is set in a stainless steel liquid permeable cell with a diameter of 41 mm, and the alcohol such as the separator is washed with water, and then the water is allowed to permeate at a differential pressure of about 50000 Pa. The water permeation amount per unit time, unit pressure, and unit area was calculated from the water permeation amount (cm ³ ) at the time, and this was taken as the water permeability. Ν is a gas constant R (= 8.314), an absolute temperature T (K), a circumference π, and an average molecular weight M of air (= 2.896 × 10 ⁻² kg / mol). Used to determine.
ν = ((8R × T) / (π × M)) ^1/2

<Battery evaluation>
-Initial charging / discharging The obtained non-aqueous electrolyte secondary battery (hereinafter, also simply referred to as "battery") is accommodated in a thermostatic bath (manufactured by Futaba Kagaku, PLM-73S, manufactured by Futaba Kagaku) and charged. It connected to the discharge device (ASKA Electronics Co., Ltd. charge / discharge device ACD-01). Next, the battery was charged at a constant current of 0.05 C, reached 4.8 V, charged at a constant voltage of 4.8 V for 2 hours, and discharged to 3.0 V at a constant current of 0.3 C. 1C is a current value at which the battery is discharged in one hour.

・ Continuous charge characteristic test The battery after the above initial charge / discharge is housed in a thermostatic chamber (manufactured by Futaba Kagaku Co., Ltd., thermostatic chamber PLM-73S) set at 55 ° C., and a charge / discharge device (manufactured by Asuka Electronics Co., Ltd., charge / discharge). Connected to device ACD-01). Next, the battery was charged with a constant current of 0.5 C, reached 4.8 V, charged for 6 hours at a constant voltage of 4.8 V, and the current value at 6 hours was confirmed as a leakage current value. Thereafter, the battery was discharged to 3.0 V with a constant current of 0.5C. Similarly, the leakage current value at 6 hours was confirmed when charging was performed at a constant voltage of 4.9 V for 6 hours. The leak current value indicates the magnitude of a side reaction accompanied by gas generation such as electrolyte decomposition. The larger the leak current value, the more the electrolyte decomposition occurs and the more the gas generation amount.

-Cycle test The battery after the continuous charge characteristic test is housed in a thermostat set at 55 ° C (manufactured by Futaba Kagaku Co., Ltd., thermostat PLM-73S), and a charge / discharge device (manufactured by Asuka Electronics Co., Ltd., charge / discharge device) ACD-01). The battery was then charged to 4.8V with a constant current of 0.5C and discharged to 3.0V with a constant current of 0.5C. This series of charging and discharging was defined as one cycle, and charging and discharging were further performed for 28 cycles. Subsequently, the battery was charged with a constant current of 0.1 C, reached 4.8 V, charged with a constant voltage of 4.8 V for 1 hour, and discharged to 3.0 V with a constant current of 0.1 C ( 30th cycle). The discharge capacities of the first cycle and the 30th cycle were confirmed.

Storage test The battery after the above initial charge / discharge is housed in a thermostatic chamber (manufactured by Futaba Kagaku Co., Ltd., thermostatic chamber PLM-73S) set at 55 ° C., and a charge / discharge device (manufactured by Asuka Electronics Co., Ltd., charge / discharge device ACD) −01). Next, the battery was charged with a constant current of 0.5 C, reached 4.8 V, and then discharged to 3.0 V with a constant current of 0.5 C, and the discharge capacity at that time was confirmed as the discharge capacity before storage did. The battery was stored as it was in a thermostatic bath for 5 days, and taken out after 5 days.

  Then, the battery was accommodated in a thermostat (manufactured by Futaba Kagaku Co., Ltd., thermostat PLM-73S) set at 25 ° C., and connected to a charge / discharge device (ASKA Electronics Co., Ltd., charge / discharge device ACD-01). Then, the battery was charged with a constant current of 0.5C, reached 4.8V, charged with a constant voltage of 4.8V for 1 hour, discharged to 3.0V with a constant current of 0.5C, The discharge capacity at that time was confirmed as the discharge capacity after storage.

-High-speed charge / discharge test The battery after the initial charge / discharge is housed in a thermostat set at 25 ° C (manufactured by Futaba Kagaku Corporation, thermostat PLM-73S), and a charge / discharge device (ASKA Electronics Co., Ltd., charge / discharge). Connected to device ACD-01). Next, the battery was charged with a constant current of 1/3 C, reached 4.8 V, charged for 1 hour with a constant voltage of 4.8 V, and discharged to 3.0 V with a constant current of 1/3 C. Next, the battery was charged with a constant current of 1/3 C, reached 4.8 V, charged for 1 hour with a constant voltage of 4.8 V, and discharged to 3.0 V with a constant current of 5 C. Next, the battery was charged with a constant current of 1/3 C, reached 4.8 V, charged for 1 hour with a constant voltage of 4.8 V, and discharged to 3.0 V with a constant current of 10 C. Maintaining discharge capacity when discharging to 3.0V with a constant current of 5C and discharging to 3.0V with a constant current of 10C, based on the discharge capacity when discharging to 3.0V with a constant current of 1 / 3C The rate (%) was confirmed.

<Example 2>
Implemented except for using Li ₂ CO ₃ with an average particle diameter of 10 μm of 0.9% by mass with respect to the amount of the positive electrode active material instead of 1.0% by mass of Li ₃ PO ₄ with respect to the amount of the positive electrode active material In the same manner as in Example 1, a nonaqueous electrolyte secondary battery was produced and evaluated for the battery. The results are shown in Table 1.

<Example 3>
Implemented except that Li ₂ SiO ₃ with an average particle size of 30 μm and 0.8 mass% based on the amount of the positive electrode active material was used instead of 1.0 mass% Li ₃ PO ₄ with respect to the amount of the positive electrode active material In the same manner as in Example 1, a nonaqueous electrolyte secondary battery was produced and evaluated for the battery. The results are shown in Table 1.

<Example 4>
Implemented except that instead of 1.0% by mass of Li ₃ PO ₄ with respect to the positive electrode active material amount, 1.4% by mass of Na ₃ PO ₄ with an average particle diameter of 10 μm with respect to the positive electrode active material amount was used. In the same manner as in Example 1, a nonaqueous electrolyte secondary battery was produced and evaluated for the battery. The results are shown in Table 1.

<Example 5>
A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that Na ₃ PO ₄ having an average particle diameter of 105 μm was used instead of Na ₃ PO ₄ having an average particle diameter of 10 μm, and the battery was evaluated. It was. The results are shown in Table 1.

<Example 6>
A nonaqueous electrolyte secondary battery was fabricated in the same manner as in Example 4 except that Na ₃ PO ₄ having an average particle diameter of 60 μm was used instead of Na ₃ PO ₄ having an average particle diameter of 10 μm, and the battery was evaluated. It was. The results are shown in Table 1.

<Example 7>
A nonaqueous electrolyte secondary battery was fabricated in the same manner as in Example 4 except that Na ₃ PO ₄ having an average particle diameter of 5 μm was used instead of Na ₃ PO ₄ having an average particle diameter of 10 μm, and the battery was evaluated. It was. The results are shown in Table 1. The particle size was adjusted by the following method.

<Adjustment of average particle size>
Dissolve 20 g of Na ₃ PO ₄ in 50 ml of purified water in a 100 ml beaker, leave it on a hot plate at 40 ° C. for 3 days to remove water, and further vacuum dry at 100 ° C. to obtain an average particle size 180 μm Na ₃ PO ₄ was obtained. The obtained Na ₃ PO ₄ was pulverized using a mortar and pestle, and then passed through sieves having openings of 130 μm, 80 μm, 15 μm and 5 μm, so that Na ₃ PO ₄ having an average particle size of 105 μm, 60 μm, 10 μm and 5 μm was obtained. Particles were obtained.

<Example 8>
In the same manner as in Example 4 except that 14% by mass of Na ₃ PO ₄ with respect to the amount of the positive electrode active material was used instead of 1.4% by mass of Na ₃ PO ₄ with respect to the amount of the positive electrode active material, A nonaqueous electrolyte secondary battery was produced and evaluated. The results are shown in Table 1.

<Example 9>
The same procedure as in Example 4 was performed except that 0.02% by mass of Na ₃ PO ₄ with respect to the amount of the positive electrode active material was used instead of 1.4% by mass of Na ₃ PO ₄ with respect to the amount of the positive electrode active material. Then, a non-aqueous electrolyte secondary battery was produced and evaluated. The results are shown in Table 1.

<Example 10>
A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that LiNi _0.5 Mn _1.5 O ₄ having a specific surface area of 0.48 m ² / g was used, and the battery was evaluated. The results are shown in Table 1. Incidentally, showing the manufacturing method of the nitrogen adsorption specific surface area ^{_{0.48m 2 / g LiNi 0.5 Mn 1.5}} O 4 of the following.

<Synthesis of positive electrode active material>
・ Synthesis of LiNi _0.5 Mn _1.5 O _{4 with} a nitrogen adsorption specific surface area of 0.48 m ² / g As a molar ratio of transition metal elements, nickel sulfate and manganese sulfate in a ratio of 1: 3 were dissolved in water, and the metal ion concentration A nickel-manganese mixed aqueous solution was prepared so that the total was 2 mol / L. Subsequently, this nickel-manganese mixed aqueous solution was dropped into 3000 mL of a 2 mol / L sodium carbonate aqueous solution heated to 70 ° C. at an addition rate of 12.5 mL / min for 120 minutes. At the time of dropping, air with a flow rate of 200 mL / min was blown into the aqueous solution while stirring. As a result, a precipitated substance was generated, and the obtained precipitated substance was sufficiently washed with distilled water and dried to obtain a nickel manganese compound. The obtained nickel-manganese compound and lithium carbonate having a particle size of 2 μm were weighed so that the molar ratio of lithium: nickel: manganese was 1: 0.5: 1.5, and obtained after dry-mixing for 1 hour. The obtained mixture was baked at 1000 ° C. for 8 hours in an oxygen atmosphere to obtain a positive electrode active material represented by LiNi _0.5 Mn _1.5 O ₄ . The specific surface area was measured with nitrogen using an autosorb-1 manufactured by Cantachrome Co., Ltd. and calculated by the BET method. The nitrogen adsorption specific surface area of the obtained LiNi _0.5 Mn _1.5 O ₄ active material was 0.48 m ² / g.

<Example 11>
Instead of mixing 1.4% by mass of Na ₃ PO ₄ with respect to the amount of the positive electrode active material into the positive electrode, the positive electrode does not contain Na ₃ PO ₄ and is 2.0% by mass with respect to the amount of the negative electrode active material. Except that Na ₃ PO _{4 (} corresponding to 0.8% by mass with respect to the positive electrode active material at the time of producing the nonaqueous electrolyte secondary battery) was mixed with the negative electrode and used in the same manner as in Example 4, nonaqueous An electrolyte secondary battery was produced and evaluated. The results are shown in Table 1. In addition, the manufacturing method of a negative electrode is shown below.

<Production of negative electrode>
Graphite powder (OMAC1.2H / SS, manufactured by Osaka Gas Chemical Co., Ltd.) and graphite powder (TIMCAL, SFG6) as a negative electrode active material, and styrene-butadiene rubber (SBR) and an aqueous carboxymethylcellulose solution as a binder, 90:10: Mixed at a solids weight ratio of 1.5: 1.8. Further, Na ₃ PO ₄ , which is solid particles having an average particle diameter of 10 μm, is added to the obtained mixture by 2.0 mass% with respect to the amount of the negative electrode active material (the positive electrode active material at the time of producing the nonaqueous electrolyte secondary battery) Was added to water as a dispersion solvent to prepare a slurry-like solution so that the solid content concentration was 45% by mass. This slurry-like solution was applied to one side of a copper foil having a thickness of 18 μm, and the solvent was removed by drying, followed by rolling with a roll press. The rolled product was punched into a disk shape having a diameter of 16 mm to obtain a negative electrode.

<Example 12>
Instead of mixing 1.4% by mass of Na ₃ PO ₄ with respect to the amount of the positive electrode active material into the positive electrode, the positive electrode does not contain Na ₃ PO ₄ and 1 mol% of NaPF with respect to the mol amount of LiPF _{6. A} non-aqueous electrolyte secondary battery was produced and evaluated in the same manner as in Example 4 except that the electrolyte containing ₃ PO ₄ was used. The results are shown in Table 2. In addition, the preparation method of a nonaqueous electrolyte is shown below.

<Example 13>
A nonaqueous electrolyte secondary battery was fabricated and evaluated in the same manner as in Example 12 except that 12 mol% of Na ₃ PO ₄ was included in the electrolytic solution with respect to the molar amount of LiPF ₆ . . The results are shown in Table 2. In addition, the preparation method of a nonaqueous electrolyte is shown below.

<Preparation of non-aqueous electrolyte>
LiPF ₆ was dissolved in a mixed solvent in which ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed at a volume ratio of 1: 2 so as to be 1 mol / L to obtain an electrolytic solution which is a nonaqueous electrolyte. Further, Na ₃ PO ₄ is added to the electrolyte so as to have the above amount, and the mixture is set on a shaker (SR-1 manufactured by Taitec Co., Ltd.), and shaken for 15 min at a speed of 150 r / min. ₃ An electrolytic solution in which PO ₄ was suspended was obtained.

<Example 14>
A non-aqueous electrolyte secondary battery was fabricated and evaluated in the same manner as in Example 4 except that the outer package was changed from a disk shape to an aluminum laminate film. The results are shown in Table 2. Different parts in the production of the nonaqueous electrolyte secondary battery are shown below.

<Production of aluminum laminated film exterior square battery>
The positive electrode and the negative electrode were cut into a width of about 40 mm and a length of 60 mm, respectively, and a positive electrode lead and a negative electrode lead were attached. A laminated body in which a positive electrode and a negative electrode are laminated on both sides of a separator (thickness 25 μm, porosity 50%, pore diameter 0.1 μm to 1 μm) made of a polypropylene microporous film is formed into a bag-like shape made of an aluminum laminate film. It put in the exterior member. Next, 2.0 mL of an electrolyte solution having a volume ratio of 1: 2 of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in which 1 mol / l of LiPF ₆ was dissolved was injected therein, and the bag was heat-sealed and sealed. Thus, an aluminum laminate film-covered prismatic battery was obtained.

<Example 15>
Instead of containing Na ₃ PO _{4 in the} positive electrode, the same procedure as in Example 14 was used except that an exterior body in which Na ₃ PO ₄ was supported inside the aluminum laminate film obtained as follows was used. A water electrolyte secondary battery was produced and evaluated. The results are shown in Table 2.

<Supporting Na ₃ PO ₄ on Aluminum Laminate Film>
10 g of Na ₃ PO ₄ was added to 10 g of NMP solution containing 8% by mass of PVDF and stirred to obtain a PVDF / NMP dispersion containing 50% by mass of Na ₃ PO ₄ . This was applied to the inside of the aluminum laminate film so that Na ₃ PO ₄ was 1.0% by mass with respect to the positive electrode active material, and then dried at 100 ° C. for 2 hours under vacuum to carry Na ₃ PO ₄ . An aluminum laminate film was obtained.

<Example 16>
Implemented except that K ₃ PO ₄ having an average particle diameter of 50 μm of 1.8% by mass with respect to the amount of the positive electrode active material was used instead of 1.0% by mass of Li ₃ PO ₄ with respect to the amount of the positive electrode active material. In the same manner as in Example 1, a nonaqueous electrolyte secondary battery was produced and evaluated for the battery. The results are shown in Table 2.

<Example 17>
Instead of 1.0% by mass of Li ₃ PO ₄ with respect to the amount of the positive electrode active material, 1.3% by mass of Ca ₃ (PO ₄ ) ₂ having an average particle diameter of 10 μm with respect to the amount of the positive electrode active material was used. Except that, a non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1, and the battery was evaluated. The results are shown in Table 2.

<Example 18>
Example 1 except that AlPO ₄ having an average particle diameter of 10 μm of 1.1% by mass with respect to the amount of the positive electrode active material was used instead of 1.0% by mass of Li ₃ PO ₄ with respect to the amount of the positive electrode active material. In the same manner as described above, a non-aqueous electrolyte secondary battery was produced and evaluated for the battery. The results are shown in Table 2.

<Example 19>
Instead of mixing the Na ₃ PO ₄ in the positive electrode, except for using LiNi _0.5 Mn _1.5 O ₄ coated with Na ₃ PO ₄ 1.4% by weight, in the same manner as in Example 4, a non-aqueous electrolyte secondary A secondary battery was prepared and evaluated. The results are shown in Table 2.

<Coating>
-LiNi _0.5 Mn _1.5 O ₄ Na ₃ PO ₄ Coating 0.50 g of Na ₃ PO ₄ was dissolved in 50 mL of purified water to prepare 50 mL of a 0.06 mol / L Na ₃ PO ₄ aqueous solution. Next, 35 g of LiNi _0.5 Mn _1.5 O ₄ was added to a 0.06 mol / L Na ₃ PO ₄ aqueous solution and stirred for 1 hour, followed by drying to remove water, thereby removing 1.4% by mass of Na _3. LiNi _0.5 Mn _1.5 O ₄ coated with PO ₄ was obtained. The amount of coating is measured using ICP (Optima 8300 manufactured by Perkin Elmer) for Na ₃ PO ₄ coated LiNi _0.5 Mn _1.5 O ₄ acid-decomposed by microwave (TOPwave (registered trademark) manufactured by Analyque Jena). I confirmed that.

<Example 20>
Instead of Na ₃ PO _4, except for using LiNi _0.5 Mn _1.5 O ₄ coated with K ₃ PO ₄ 1.8% by weight, in the same manner as in Example 19, producing a non-aqueous electrolyte secondary battery Then, battery evaluation was performed. The results are shown in Table 2.

<Coating>
-LiNi _0.5 Mn _1.5 O ₄ K ₃ PO ₄ coating 0.63 g of K ₃ PO ₄ was dissolved in 50 mL of purified water to prepare 50 mL of a 0.06 mol / L aqueous K ₃ PO ₄ solution. Next, 35 g of LiNi _0.5 Mn _1.5 O ₄ was added to 0.06 mol / L K ₃ PO ₄ aqueous solution and stirred for 1 hour, followed by drying to remove water and 1.8% by mass of K ₃ LiNi _0.5 Mn _1.5 O ₄ coated with PO ₄ was obtained. The amount of coating is measured using ICP (Optima 8300 manufactured by Perkin Elmer) for K ₃ PO ₄ coated LiNi _0.5 Mn _1.5 O ₄ acid-decomposed by microwave (TOPwave (registered trademark) manufactured by Analiquiena). I confirmed that.

<Example 21>
The nonaqueous electrolyte secondary was the same as in Example 4 except that the amount of the positive electrode active material of the positive electrode was changed to LiNi _1/3 Mn _1/3 Co _1/3 O ₂ and the charging voltage was all changed to 4.2V. A battery was prepared and evaluated. The results are shown in Table 3.

<Synthesis of LiNi _1/3 Mn _1/3 Co _1/3 O ₂ >
A nickel-manganese-cobalt mixed aqueous solution in which nickel sulfate, manganese sulfate, and cobalt sulfate in a molar ratio of the transition metal element of 1: 1: 1 are dissolved in water so that the total metal ion concentration is 2 mol / L. Was prepared. Subsequently, this nickel-manganese-cobalt mixed aqueous solution was dropped into 3000 mL of a 2 mol / L sodium carbonate aqueous solution heated to 70 ° C. at an addition rate of 12.5 mL / min for 120 minutes. At the time of dropping, nitrogen at a flow rate of 200 mL / min was bubbled into the aqueous solution while stirring. As a result, a precipitated substance was generated, and the obtained precipitated substance was sufficiently washed with distilled water and dried to obtain a nickel manganese cobalt compound. The obtained nickel manganese cobalt compound and lithium carbonate having a particle size of 2 μm were weighed so that the molar ratio of lithium: nickel: manganese: cobalt was 3: 1: 1: 1 and dry-mixed for 1 hour. The obtained mixture was fired at 950 ° C. for 5 hours in the air to obtain a positive electrode active material represented by LiNi _1/3 Mn _1/3 Co _1/3 O ₂ . The obtained NiNi _1/3 Mn _1/3 Co _1/3 O ₂ active material had a nitrogen adsorption specific surface area of 1.0 m ² / g.

<Comparative Example 1>
A non-aqueous electrolyte secondary battery was produced and evaluated in the same manner as in Example 1 except that the positive electrode did not contain Li ₃ PO ₄ . The results are shown in Table 2.

<Comparative example 2>
A non-aqueous electrolyte secondary battery was produced and evaluated in the same manner as in Example 14 except that the positive electrode did not contain Na ₃ PO ₄ . The results are shown in Table 2.

<Comparative Example 3>
The non-aqueous electrolyte secondary battery is the same as Comparative Example 1 except that the positive electrode active material amount of the positive electrode is changed to LiNi _1/3 Mn _1/3 Co _1/3 O ₂ and the charging voltage is changed to 4.2V. The battery was evaluated. The results are shown in Table 3.

充電電圧４．８Ｖ ＬｉＮｉ_0.5Ｍｎ_1.5Ｏ₄

Charging voltage 4.8V LiNi _0.5 Mn _1.5 O ₄

充電電圧４．８Ｖ ＬｉＮｉ_0.5Ｍｎ_1.5Ｏ₄

Charging voltage 4.8V LiNi _0.5 Mn _1.5 O ₄

充電電圧４．２Ｖ ＬｉＮｉ_1/3Ｍｎ_1/3Ｃｏ_1/3Ｏ₂

Charging voltage 4.2V LiNi _1/3 Mn _1/3 Co _1/3 O ₂

  According to the present invention, the effect of improving leakage current, cycle characteristics, and storage characteristics is exhibited even under a voltage condition of 4.2 V, but it is apparent that a greater improvement effect is exhibited under higher voltage conditions.

  The nonaqueous electrolyte secondary battery of the present invention has industrial applicability to various consumer equipment power supplies and automobile power supplies.

Claims (17)

A positive electrode, a negative electrode, a non-aqueous electrolyte, and an outer package,
A nonaqueous electrolyte secondary battery in which at least one of the positive electrode, the negative electrode, the nonaqueous electrolyte, and the outer package contains a basic compound.   The nonaqueous electrolyte secondary battery according to claim 1, wherein a base dissociation constant (pKb) of an anion contained in the basic compound is 10.83 or less. The anion contained in the basic compound is at least one selected from the group consisting of PO ₄ ³⁻ , HPO ₄ ²⁻ , CO ₃ ²⁻ , HCO ₃ ⁻ , and SiO ₃ ^2−. 2. The nonaqueous electrolyte secondary battery according to 2. 4. The nonaqueous electrolyte secondary battery according to claim 1, wherein the anion contained in the basic compound is at least one selected from the group consisting of PO ₄ ³⁻ and HPO ₄ ^2−. . The cation contained in the basic compound is at least one selected from the group consisting of Na ⁺ , K ⁺ , Be ²⁺ , Mg ²⁺ , Ca ²⁺ , and Al ³⁺ . The nonaqueous electrolyte secondary battery according to any one of the above. The basic _{compound, Na 3 PO 4, K 3} PO 4, Ca 3 (PO 4) 2, and AlPO is at least one selected from the group consisting of _4, in any one of claims 1 to 5 The nonaqueous electrolyte secondary battery as described.   The nonaqueous electrolyte secondary battery according to claim 1, wherein the basic compound has an average particle size of 0.1 to 100 μm.   The nonaqueous electrolyte secondary battery according to claim 1, wherein the basic compound has an average particle size of 10 to 50 μm. The non-aqueous electrolyte secondary battery according to claim 1, wherein the positive electrode includes a positive electrode active material, and the specific surface area of the positive electrode active material is 0.6 m ² / g or more.   The non-aqueous electrolyte secondary battery according to claim 1, wherein the positive electrode active material includes a lithium transition metal oxide containing manganese.   The nonaqueous electrolyte secondary battery according to claim 9 or 10, comprising 0.1 to 10% by mass of the basic compound with respect to the amount of the positive electrode active material.   The nonaqueous electrolyte secondary battery according to any one of claims 9 to 11, wherein a potential of the positive electrode active material is 4.5 V or more based on lithium. The positive electrode active material has the following general formula (1):
Li _x Mn _{2- y My} O _z (1)
(In the formula, M represents at least one element selected from the group consisting of transition metal elements, and 0 <x ≦ 1.3, 0.2 <y <0.8, 3.5 <z <4. 5)
The nonaqueous electrolyte secondary battery of any one of Claims 9-12 containing the oxide represented by these.   The non-aqueous electrolyte secondary battery according to claim 1, wherein the non-aqueous electrolyte includes lithium hexafluorophosphate.   The nonaqueous electrolyte secondary battery according to claim 14, wherein the basic compound is included in an amount of 0.001 to 10 mol% with respect to lithium hexafluorophosphate included in the nonaqueous electrolyte.   The nonaqueous electrolyte secondary battery according to any one of claims 1 to 15, wherein the outer package is a square type and / or a laminate type.   The nonaqueous electrolyte secondary battery according to any one of claims 1 to 16, wherein the nonaqueous solvent contained in the nonaqueous electrolyte does not contain an F element.