JP2016085885A - Lithium ion secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery which can be charged and discharged with stability over a long period of time and is superior in safety even if it is a high-energy density battery.SOLUTION: A lithium ion secondary battery comprises: a positive electrode; a negative electrode; a nonaqueous electrolyte; and a separator. When the lithium ion secondary battery is full-charged, its positive electrode potential is 4.1 V(vs Li/Li) or higher on a lithium basis. The positive electrode includes cobalt for a positive electrode active material. The separator has a layer including an inorganic substance at least on one side thereof. On the surface of the separator, facing the negative electrode, an inorganic substance layer is present.SELECTED DRAWING: None

Description

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

  With the recent development of electronic technology and increasing interest in environmental technology, various electrochemical devices have been developed. This is based on the diversification of scale, usage, and specifications of energy creation (power generation) and energy storage (storage). For this reason, the request | requirement with respect to the electrochemical device development corresponding to them is strong, and the expectation for this is increasing. As such an electrochemical device, a solar cell etc. are mentioned as an electric power generation device, for example, A secondary battery, a capacitor, a capacitor | condenser etc. are mentioned as an electrical storage device. Lithium ion secondary batteries, which are typical examples of power storage devices, have been used mainly as rechargeable batteries for portable devices, but in recent years, they have been used as batteries for hybrid and electric vehicles, or stationary storage batteries, aircraft It is also beginning to be used in large applications such as industrial applications and space satellite industrial applications.

A lithium ion secondary battery generally has a configuration in which a positive electrode and a negative electrode mainly composed of an active material capable of inserting and extracting lithium are arranged via a separator. The positive electrode of the lithium ion secondary battery includes LiCoO ₂ , LiNiO ₂ or LiMn ₂ O ₄ as a positive electrode active material, carbon black or graphite as a conductive agent, and polyvinylidene fluoride, latex or rubber as a binder. Is formed by covering a positive electrode current collector made of aluminum or the like. The negative electrode is a negative electrode mixture in which coke or graphite or the like as a negative electrode active material and polyvinylidene fluoride, latex or rubber as a binder are mixed, and a lithium metal on a negative electrode current collector made of copper or the like. It is formed by coating. Further, the separator is made of porous polyolefin or the like, and its thickness is very thin, from several μm to several hundred μm. The positive electrode, the negative electrode, and the separator are immersed in the electrolytic solution in the battery. The electrolyte is formed, for example, by dissolving a lithium salt such as LiPF ₆ or LiBF ₄ in an aprotic solvent such as propylene carbonate or ethylene carbonate, or in a polymer such as polyethylene oxide.

  Compared to other storage batteries, lithium ion secondary batteries have features such as high electromotive force, high energy density, and repeated charge / discharge durability, and are widely used, but automobiles that are expected to expand in the future In the use of lithium ion secondary batteries such as stationary ones, higher energy density and repeated durability are required than before. Since new applications are mainly large-scale applications, further improvements in safety and reliability are required. In addition, since the amount of information handled by devices is increasing in conventional small device applications, batteries with high capacity and high energy density are required.

  In order to respond to such a demand for higher energy density, for example, a positive electrode material having a high lithium content that can be occluded / desorbed has been developed. For this purpose, various additives have been studied.

  As a positive electrode active material, a battery using a high-capacity positive electrode or a battery driven at a high voltage using a high-potential positive electrode has been developed as a countermeasure for increasing the energy density.

Conventionally, LiCoO ₂ is often used as the positive electrode active material. However, the capacity of the positive electrode single electrode that can be charged and discharged in the potential range of 4.2 V to 3.0 V is as low as 150 mAh / g or less. Therefore, in order to further increase the energy density, it is necessary to improve the material itself. Therefore, it has been studied to use a material in which a part of Co in LiCoO ₂ is replaced with another metal such as Ni or Mn in the positive electrode active material. For example, a LiNi _1/3 Mn _1/3 Co _1/3 O ₂ positive electrode active material using Ni, Mn and Co in the same amount has been developed and used. Here, since Ni is one effective method for increasing the energy density, a positive electrode material having a further increased Ni ratio has been developed.

Further, LiCoO ₂ has been conventionally used as a positive electrode active material, and a high capacity positive electrode or a positive electrode for a battery driven at a high voltage has been developed by doping or coating a small amount of other metal on the surface or inside thereof.
In addition, various new positive electrode materials have been developed as positive electrode materials with a large amount of lithium that can be occluded / desorbed, such as a positive electrode active material with a large amount of Li per unit called a Li-rich positive electrode.
In this way, there are various positive electrode active materials such as those that have been used in the past and those that have been newly developed, but there is a balance between the charge / discharge characteristics, safety, reliability, availability, and handling properties of the battery. From the viewpoint, many of the crystal structures contain Co.

  Both a battery using a high capacity positive electrode and a battery using a high potential positive electrode need to drive the positive electrode at a higher voltage than a conventional battery. When driven at a high voltage, due to the strength of the oxidizing power, the battery is remarkably deteriorated and deteriorated in performance, and it is difficult to maintain the high quality of the battery. Specifically, with charge and discharge, the constituent components of the electrolytic solution and the separator are decomposed on the surface of the positive electrode, and it has been difficult to achieve a highly reliable battery over a long period of time.

  Therefore, studies have been made to include various additives in the electrolytic solution or to form an insulating layer on the separator.

As additives to be contained in the electrolytic solution, for example, fluorine-containing carbonate compounds, sulfur-containing compounds, nitrile compounds, phosphoric acid compounds, silicon-containing compounds and the like have been studied, and certain effects have been recognized (for example, (See Patent Documents 1 to 4). Since the additive is effective when added in a small amount, it is effective in that the other characteristics are hardly sacrificed.
Moreover, examination which forms the layer containing an inorganic particle in part or the whole on a separator is also examined (for example, refer to patent documents 5). The inorganic particle layer is useful in that it contributes to improving safety by suppressing thermal runaway and short-circuiting, but it is particularly effective in suppressing deterioration of the separator that is accelerated when the battery is driven at high voltage using a positive electrode with a high potential. Is also effective.

  Thus, in order to achieve a battery having a high energy density, each member such as a positive electrode active material, an electrolyte solution additive, and a separator has been developed. However, there are still few studies to combine them effectively, and it has not been possible to maximize the capabilities and advantages of each member.

JP 2012-123989 A JP 2010-244502 A International Publication No. 2012/77712 Pamphlet JP 2000-223152 A International Publication No. 2008/093575 Pamphlet

  As described above, various battery materials for achieving a battery with high energy density that combines safety and reliability have been studied, but a battery having these performances has not been achieved. In particular, a battery with a high energy density is more likely to generate a gas or elute a metal than a conventional battery, thereby reducing repeated charge / discharge durability and safety. Tended to be.

  Accordingly, an object of the present invention is to provide a battery that can be stably charged / discharged over a long period of time and is excellent in safety even for a battery having a high energy density.

  As a result of intensive research in order to solve the above problems, the inventors of the present invention have a battery including a positive electrode material containing Cо as a positive electrode active material and a separator having a layer of inorganic particles. It has been found that the use of the layer on the side facing the negative electrode can solve the above problems, and the present invention has been completed. That is, the present invention is as follows:

｛式中、Ｍは、リン原子又はホウ素原子を示し、Ｍがリン原子のとき、ｗは０又は１であり、Ｍがホウ素原子のときｗは０であり、Ｒ¹、Ｒ²、及びＲ³は、各々独立に、置換されていてもよい炭素数１〜１０の有機基を示し、そしてＲ⁴及びＲ⁵は、各々独立に、ＯＨ基、ＯＬｉ基、置換されてもよい炭素数１〜１０のアルキル基、置換されてもよい炭素数１〜１０のアルコキシ基、炭素数３〜１０のシロキシ基、炭素数６〜１５のアリール基、及び炭素数６〜１５のアリールオキシ基からなる群より選ばれる基を示す。｝で表される化合物、及び／又は下記式（２）：

｛式中、Ｒ¹、Ｒ²、及びＲ³は、各々独立に、置換されていてもよい炭素数１〜１０の有機基を示し、そしてＲ⁶は、置換されていてもよい炭素数１〜２０の有機基を示す。｝で表される化合物を含む、［１］〜［４］のいずれかに記載のリチウムイオン二次電池。
［６］
前記無機物が金属酸化物、金属水酸化物、炭酸塩、硫酸塩又は粘土鉱物から選ばれる群のいずれか一種以上を含む、［１］〜［５］のいずれかに記載のリチウムイオン二次電池
［７］
前記セパレータのベースの膜が有機樹脂である、［１］〜［６］のいずれかに記載のリチウムイオン二次電池。
［８］
満充電時におけるリチウム基準の正極電位が、４．２Ｖ（ｖｓＬｉ／Ｌｉ⁺）を上回る、［１］〜［７］のいずれかに記載のリチウムイオン二次電池。
［９］
前記正極活物質が、
下記式（３）：
ＬｉＣо_1-uＭｅ_uＯ₂ （３）
｛式中、Ｍｅは、Ｃｏを除く遷移金属から成る群より選ばれる１種以上を示し、そしてｕは、０．１≦ｕ≦０．９の範囲内にある数である。｝
で表される酸化物、
下記式（４）：
ｚＬｉ₂ＭｃＯ₃−（１−ｚ）ＬｉＭｄＯ₂ （４）
｛式中、Ｍｃ及びＭｄは、各々独立に、遷移金属から成る群より選ばれる１種以上であっていずれか一方又は両方がＣｏを含むものを示し、そしてｚは、０．１≦ｚ≦０．９の範囲内にある数である。｝
で表される複合酸化物、
下記式（５）：
ＬｉＭｂ_1-yＣｏ_yＰＯ₄ （５）
｛式中、Ｍｂは、遷移金属から成る群より選ばれる１種以上を示し、そしてｙは、０≦ｙ≦０．９の範囲内にある数である。｝
で表される化合物、及び
下記式（６）：
Ｌｉ₂Ｍｆ_1-yＣｏ_yＰＯ₄Ｆ （６）
｛式中、Ｍｆは、遷移金属から成る群より選ばれる１種以上を示し、そしてｙは、０≦ｙ≦０．９の範囲内にある数である。｝
で表される化合物、
から成る群より選ばれる１種以上である、［１］〜［８］のいずれかに記載のリチウムイオン二次電池。
［１０］
前記セパレータの正極に対向する面に存在する無機物量は、負極に対向する面に存在する無機物量以下である、［１］〜［９］のいずれかに記載のリチウムイオン二次電池。
［１１］
前記正極活物質が、４．４Ｖ（ｖｓＬｉ／Ｌｉ⁺）以上の電位において１０ｍＡｈ／ｇ以上の放電容量を有する、［１］〜［１０］のいずれかに記載のリチウムイオン二次電池。 [1]
A positive electrode containing cobalt in the positive electrode active material;
A negative electrode,
A non-aqueous electrolyte,
A separator having a layer containing an inorganic substance on at least one side;
A lithium-ion secondary battery having a lithium-based positive electrode potential of 4.1 V (vsLi / Li ⁺ ) or higher when fully charged,
A lithium ion secondary battery in which an inorganic layer is present on the surface of the separator facing the negative electrode.
[2]
A non-aqueous electrolyte and a non-aqueous solvent,
Lithium salt,
A silicon-containing compound in which one or more hydrogen atoms of one or more compounds selected from the group consisting of inorganic acids, organic acids, acid amides, and amines are substituted with silicon-containing functional groups;
including,
The lithium ion secondary battery according to [1].
[3]
In the silicon-containing compound, one or more hydrogen atoms of one or more compounds selected from the group consisting of an inorganic acid, a carboxylic acid, and a phosphoric acid amide formed by a bond of a base containing boron or phosphorus and hydrogen are silicon. The lithium ion secondary battery according to [2], which is a silicon-containing compound substituted with a containing functional group.
[4]
The lithium ion secondary according to any one of [2] to [3], wherein the silicon-containing compound is a compound having one or more sites represented by —Si (R ¹ ) (R ² ) (R ³ ). battery. (R ^{1 to} R ³ each independently represents an alkyl group, an alkenyl group, an alkoxy group, or an F-substituted alkyl group.)
[5]
The non-aqueous electrolyte further includes the following formula (1):

{In the formula, M represents a phosphorus atom or a boron atom; when M is a phosphorus atom, w is 0 or 1, and when M is a boron atom, w is 0, R ¹ , R ² , and R ³ each independently represents an optionally substituted organic group having 1 to 10 carbon atoms, and R ⁴ and R ⁵ each independently represents an OH group, an OLi group, or an optionally substituted carbon number of 1; An alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms that may be substituted, a siloxy group having 3 to 10 carbon atoms, an aryl group having 6 to 15 carbon atoms, and an aryloxy group having 6 to 15 carbon atoms. A group selected from the group is shown. } And / or the following formula (2):

{Wherein R ¹ , R ² , and R ³ each independently represents an optionally substituted organic group having 1 to 10 carbon atoms, and R ⁶ represents an optionally substituted carbon number 1 -20 organic groups are shown. } The lithium ion secondary battery in any one of [1]-[4] containing the compound represented by these.
[6]
The lithium ion secondary battery according to any one of [1] to [5], wherein the inorganic substance includes at least one member selected from the group consisting of metal oxides, metal hydroxides, carbonates, sulfates, and clay minerals. [7]
The lithium ion secondary battery according to any one of [1] to [6], wherein the base film of the separator is an organic resin.
[8]
The lithium ion secondary battery according to any one of [1] to [7], wherein the lithium-based positive electrode potential at the time of full charge exceeds 4.2 V (vsLi / Li ⁺ ).
[9]
The positive electrode active material is
Following formula (3):
LiCо _1-u Me _u O ₂ (3)
{In the formula, Me represents one or more selected from the group consisting of transition metals excluding Co, and u is a number in the range of 0.1 ≦ u ≦ 0.9. }
An oxide represented by
Following formula (4):
_{zLi 2 McO 3 - (1-} z) LiMdO 2 (4)
{In the formula, Mc and Md each independently represent one or more selected from the group consisting of transition metals, one or both of which contain Co, and z is 0.1 ≦ z ≦ A number in the range of 0.9. }
A composite oxide represented by
Following formula (5):
LiMb _1-y Co _y PO ₄ (5)
{In the formula, Mb represents one or more selected from the group consisting of transition metals, and y is a number in the range of 0 ≦ y ≦ 0.9. }
And a compound represented by the following formula (6):
Li ₂ Mf _1-y Co _y PO ₄ F (6)
{Wherein Mf represents one or more selected from the group consisting of transition metals, and y is a number in the range of 0 ≦ y ≦ 0.9. }
A compound represented by
The lithium ion secondary battery according to any one of [1] to [8], which is at least one selected from the group consisting of:
[10]
The lithium ion secondary battery according to any one of [1] to [9], wherein an amount of an inorganic substance existing on a surface facing the positive electrode of the separator is equal to or less than an amount of an inorganic substance existing on a surface facing the negative electrode.
[11]
The lithium ion secondary battery according to any one of [1] to [10], wherein the positive electrode active material has a discharge capacity of 10 mAh / g or more at a potential of 4.4 V (vsLi / Li ⁺ ) or more.

  According to the present invention, it is possible to achieve a high energy density battery with improved long-term characteristics of the battery.

  Hereinafter, a mode for carrying out the present invention (hereinafter, simply referred to as “the present embodiment”) will be described in detail. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention. Deformation is possible.

<Lithium ion secondary battery>
In the present embodiment, the lithium ion secondary battery is a high energy density battery including a non-aqueous electrolyte, a separator, a positive electrode, and a negative electrode. The positive electrode contains Cо in the positive electrode active material, and the separator has a layer containing an inorganic material on one or both surfaces of the surface, and the inorganic material exists at least on the surface facing the negative electrode.
The non-aqueous electrolyte contains a silicon-containing compound in which one or more hydrogen atoms of one or more compounds selected from the group consisting of inorganic acids, organic acids, acid amides, and amines are substituted with silicon-containing functional groups. It is preferable.

  In the nonaqueous electrolytic solution according to the present embodiment, decomposition of the electrolytic solution-forming component is suppressed during charge / discharge or storage, metal elution from the positive electrode active material is suppressed, or needle-like growth of the negative electrode dendride is suppressed. Therefore, it is possible to form a battery with excellent reliability and safety that can perform stable charge and discharge over a long period of time.

  Components such as the non-aqueous electrolyte, the separator, the positive electrode, and the negative electrode will be described below.

[Non-aqueous electrolyte]
In the present embodiment, the nonaqueous electrolytic solution includes a lithium salt and a nonaqueous solvent. Further, an additive may be included, and it is preferable that a silicon-containing compound is included as an additive. Further, it may contain components such as hydrofluoric acid and water.

[Lithium salt]
The non-aqueous electrolyte according to this embodiment uses a lithium salt as an electrolyte. Although it does not specifically limit as lithium salt, For example, the inorganic lithium salt which does not contain a carbon atom in an anion, the organic lithium salt which contains a carbon atom in an anion, etc. are mentioned. In addition, as lithium salt, inorganic lithium salt or organic lithium salt may be used individually by 1 type, or these may be used together.

Although it does not specifically limit as said inorganic lithium salt, For example, what is used as a normal nonaqueous electrolyte can be used. Such an inorganic lithium salt is not particularly limited. For example, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , Li ₂ SiF ₆ , LiSbF ₆ , LiAlO ₄ , LiAlCl ₄ , Li ₂ B ₁₂ F _b H _{12 -b} (b is an integer of 0 to 3), a lithium salt bonded to a polyvalent anion, and the like. These inorganic lithium salts may be used alone or in combination of two or more. Among these, one or more inorganic lithium salts selected from the group consisting of LiPF ₆ and LiBF ₄ are more preferable, and LiPF ₆ is more preferable. By using an inorganic lithium salt having a fluorine atom, the balance of battery characteristics tends to be more excellent. Further, by using an inorganic lithium salt having a phosphorus atom or a boron atom, ion conductivity and handleability tend to be more excellent.

Although it does not specifically limit as said organic lithium salt, For example, what is used as a normal nonaqueous electrolyte can be used. Such an organic lithium salt is not particularly limited. For example, LiN (SO ₂ C _m F _{2m + 1} ) ₂ (LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) _2, etc. m organolithium salt represented by an integer of 1 to _{8); LiPF n (C p F} 2p + 1) 6-n (n is an integer of from 1 to 5 such as LiPF ₅ (CF _3), p is 1 An organic lithium salt represented by LiBF _q (C _s F _{2s + 1} ) _4-q (q is an integer of 1 to 3, s is an integer of 1 to 8), such as LiBF ₃ (CF ₃ ) Lithium oxalate difluoroborate (LiODFB) represented by LiBF ₂ (C ₂ O ₄ ); Lithium bis (oxalato) borate (LiBOB) represented by LiB (C ₂ O ₄ ) ₂ Halogenated LiBOB typified by: LiB (C ₃ O ₄ H ₂ ) ₂ Malonate) borate (LiBMB); lithium tetrafluorooxalatophosphate represented by LiPF ₄ (C ₂ O ₂ ); organic lithium salts represented by the following formulas (7a), (7b) and (7c) It is done.
LiC (SO ₂ R ⁴ ) (SO ₂ R ⁵ ) (SO ₂ R ⁶ ) (7a)
LiN (SO ₂ OR ⁷ ) (SO ₂ OR ⁸ ) (7b)
LiN (SO ₂ R ⁹ ) (SO ₂ OR ¹⁰ ) (7c)
{In formulas (7a) to (7c), R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ each independently represents a C 1-8 perfluoroalkyl group. }

  Among these, an organic lithium salt having a boron atom is preferable. Such an organic lithium salt is structurally stable.

  In addition, the said lithium salt may be used individually by 1 type, or may use 2 or more types together.

  The concentration of the lithium salt in the nonaqueous electrolytic solution is preferably from 0.1 mol / L to 5 mol / L, more preferably from 0.5 mol / L to 3 mol / L, still more preferably from 0.8 mol / L to 2 mol / L. When the concentration of the lithium salt is within the above range, the non-aqueous electrolyte has a higher conductivity, and the charge / discharge efficiency of the non-aqueous secondary battery using the non-aqueous electrolyte tends to be higher. It is in.

[Nonaqueous solvent]
The nonaqueous electrolytic solution according to this embodiment includes a nonaqueous solvent.

  Although it does not specifically limit as a nonaqueous solvent, For example, Alcohols, such as methanol, ethanol, isopropanol; Methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, (gamma) -butyrolactone, (gamma) -valerolactone, (delta)- Acid esters such as valerolactone and ε-caprolactone; ketones such as dimethyl ketone, diethyl ketone, methyl ethyl ketone, 3-pentanone and acetone; pentane, hexane, octane, cyclohexane, benzene, toluene, xylene, fluorobenzene, hexafluorobenzene Hydrocarbons such as dimethyl ether, diethyl ether, 1,2-dimethoxyethane, 1,4-dioxane, crown ethers, glymes, tetrahydrofuran, etc .; N, N-dimethylacetamide Amides such as N, N-dimethylformamide; amines such as ethylenediamine and pyridine; propylene carbonate, ethylene carbonate, vinylene carbonate, 1,2-butylene carbonate, trans-2,3-butylene carbonate, cis-2,3- Butylene carbonate, 1,2-pentylene carbonate, trans-2,3-pentylene carbonate, cis-2,3-pentylene carbonate, vinyl ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl Carbonates such as isopropyl carbonate, dipropyl carbonate, methyl butyl carbonate, dibutyl carbonate, ethyl propyl carbonate; acetonitrile, propylene Nitriles such as onitrile, adiponitrile, succinonitrile, malononitrile, acrylonitrile, methoxyacetonitrile; lactams such as N-methylpyrrolidone (NMP); sulfones such as sulfolane, 3-methylsulfolane, dimethylsulfone, and ethylmethylsulfone; propane Examples thereof include sulfonic acid esters such as sultone and butane sultone; sulfoxides such as dimethyl sulfoxide; industrial oils such as silicon oil and petroleum; and edible oils.

  In addition, as the non-aqueous solvent, a solvent in which one or more hydrogen atoms in the solvent molecule are substituted with a halogen atom or a functional group can be used. Such a solvent is not particularly limited. For example, a compound in which one or two or more hydrogen atoms of a carbonate compound are substituted with a fluorine atom or a chlorine atom, one hydrogen atom of a nitrile or Compound in which 2 or more are substituted with fluorine atom or chlorine atom, Compound in which 1 or 2 or more of hydrogen atoms of sulfones are substituted with fluorine atom or chlorine atom, 1 of hydrogen atoms in ester compound Examples thereof include compounds in which one or two or more of them are substituted with a fluorine atom or a chlorine atom.

  Moreover, an ionic liquid can also be used as a non-aqueous solvent. Here, the “ionic liquid” refers to a liquid composed of ions obtained by combining an organic cation and an anion.

  The organic cation is not particularly limited, and examples thereof include imidazolium ions such as dialkylimidazolium cation and trialkylimidazolium cation; tetraalkylammonium ion; alkylpyridinium ion; dialkylpyrrolidinium ion; and dialkylpiperidinium ion. .

The anion serving as a counter for these organic cations is not particularly limited. For example, PF ₆ anion, PF ₃ (C ₂ F ₅ ) ₃ anion, PF ₃ (CF ₃ ) ₃ anion, BF ₄ anion, BF ₂ ( CF ₃ ) ₂ anion, BF ₃ (CF ₃ ) anion, bisoxalatoborate anion, Tf (trifluoromethanesulfonyl) anion, Nf (nonafluorobutanesulfonyl) anion, bis (fluorosulfonyl) imide anion, bis (trifluoromethanesulfonyl) ) Imide anion, bis (pentafluoroethanesulfonyl) imide anion, dicyanoamine anion, halide anion, and the like can be used.

  The non-aqueous solvent preferably contains at least one of acid esters, lactones, carbonates, ethers, and nitriles, and contains at least one of acid esters, lactones, and carbonates. Is more preferable, and it is particularly preferable that one or more carbonates are included.

  The ethers are not particularly limited, but chain ethers are preferable. Examples of chain ethers include dimethyl ether, diethyl ether, 1,2-dimethoxyethane, 1,4-dioxane, crown ethers, glyme. And tetrahydrofuran.

  The acid esters are not particularly limited, but chain esters are preferable. Examples of the chain esters include methyl acetate, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate, butyl propionate, and And dimethyl succinate, dimethyl succinate, and dimethyl malonate.

  The said non-aqueous solvent may be used individually by 1 type, or may use 2 or more types together.

  When two or more kinds of non-aqueous solvents are used in combination, one or more of them are preferably carbonates. As the carbonates, one or more of cyclic carbonates and chain carbonates are used.

  Examples of the cyclic carbonates include ethylene carbonate, propylene carbonate, butylene carbonate, 4-fluoro-1,3-dioxolan-2-one, vinylene carbonate, vinyl ethylene carbonate, 4,5-difluoro-1,3-dioxolane. -2-one and the like.

  The chain carbonates are not particularly limited, and examples thereof include ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, methyl butyl carbonate, dibutyl carbonate, and ethyl propyl carbonate. be able to.

〔Additive〕
The non-aqueous electrolyte according to the present embodiment can further contain an additive as necessary. Although it does not specifically limit as an additive used by this embodiment, For example, the substance which plays the role as a solvent which melt | dissolves lithium salt is mentioned. Such materials may substantially overlap with the non-aqueous solvent described above. Further, the additive is preferably a substance that contributes to improving the performance of the non-aqueous electrolyte and the non-aqueous secondary battery according to this embodiment, and a substance that does not directly participate in the electrochemical reaction can also be used. . Or the additive which improves safety | security or improves the handleability of battery preparation can also be used. In addition, an additive may be used individually by 1 type, or may use 2 or more types together.

  Although it does not specifically limit as an additive, For example, unsaturated bond containing cyclic carbonate represented by vinylene carbonate and vinyl ethylene carbonate; (gamma) -butyrolactone, (gamma) -valerolactone, (gamma) -caprolactone, (delta) -valerolactone, (delta) -caprolactone Lactone represented by ε-caprolactone; cyclic ether represented by 1,2-dioxane; methyl formate, methyl acetate, methyl propionate, methyl butyrate, ethyl formate, ethyl acetate, ethyl propionate, Ethyl butyrate, n-propyl formate, n-propyl acetate, n-propyl propionate, n-propyl butyrate, isopropyl formate, isopropyl acetate, isopropyl propionate, isopropyl butyrate n-butyl formate, n-butyl acetate, n-butyl propionate, n-butyl butyrate, isobutyl formate, isobutyl acetate, isobutyl propionate, isobutyl butyrate, sec-butyl formate, sec-butyl acetate , Sec-butyl propionate, sec-butyl butyrate, tert-butyl formate, tert-butyl acetate, tert-butyl propionate, tert-butyl butyrate, methyl pivalate, n-butyl pivalate, n-hexylpi Carboxyl represented by barate, n-octyl pivalate, dimethyl oxalate, ethyl methyl oxalate, diethyl oxalate, diphenyl oxalate, malonic acid ester, fumaric acid ester, maleic acid ester Esters; amides represented by N-methylformamide, N, N-dimethylformamide, N, N-dimethylacetamide; ethylene sulfite, propylene sulfite, butylene sulfite, pentene sulfite, sulfolane, 3-methylsulfolane, 3 -Cyclic sulfur compounds represented by sulfolene, 1,3-propane sultone, 1,4-butane sultone, 1,3-propanediol sulfate, tetramethylene sulfoxide, thiophene 1-oxide; monofluorobenzene, biphenyl, fluorinated biphenyl A nitro compound represented by nitromethane; a Schiff base; a Schiff base complex; an oxalate complex, an aromatic compound represented by substituted or unsubstituted benzene, biphenyl, naphthalene, and terphenyl; Trimethyl phosphate, triethyl phosphate, trimethyl phosphite, triethyl phosphite, phosphoric acid ester or phosphite represented by fluorine-substituted phosphoric acid or phosphite; difluorophosphate, monofluorophosphoric acid Examples of the salt structure include salts, nitrates, and carbonates. These may be used individually by 1 type, or may use 2 or more types together. As an additive, a silicon-containing compound is preferably used.

[Silicon-containing compound]
The silicon-containing compound preferably used as an additive of the present embodiment is a silicon-containing functional group having one or more hydrogen atoms of one or more compounds selected from the group consisting of inorganic acids, organic acids, acid amides, and amines. Is obtained by substituting The compound having such a structure exhibits an effect of protecting the positive electrode due to the effect of the silicon-containing functional group and other sites, and is effective in oxidizing and adsorbing a non-aqueous solvent, a lithium salt and other additives on the positive electrode. Reaction and elution of the positive electrode active material component into the electrolyte can be suppressed. Thereby, a battery characteristic improves more.

(Inorganic acid)
The inorganic acid is not particularly limited, and examples thereof include inorganic acids containing nonmetallic elements such as boron, fluorine, chlorine, bromine, iodine, sulfur, selenium, tellurium, nitrogen, phosphorus, and arsenic. Among these, an inorganic acid containing boron, sulfur, phosphorus, or nitrogen is preferable, an inorganic acid containing boron or phosphorus is more preferable, and an inorganic acid containing phosphorus is more preferable. Specifically, as the inorganic acid, for example, phosphoric acid, phosphorous acid, polyphosphoric acid, phosphonic acid, phosphinic acid or boric acid is preferable. By using a compound in which one or more hydrogen atoms of an inorganic acid formed by the bond of a base containing boron or phosphorus and hydrogen are substituted with a silicon-containing functional group, the effect of protecting the positive electrode is further improved, and It tends to be possible to further suppress oxidation and side reactions of the nonaqueous solvent, lithium salt and other additives on the positive electrode, and elution of the positive electrode active material component into the electrolyte. This is because boron and phosphorus tend to easily act on the metal of the positive electrode active material. Thereby, the battery characteristics tend to be further improved.

(Organic acid)
Although it does not specifically limit as an organic acid, For example, the compound which has 1 or more types of sulfonic acid or a carboxylic acid site | part is mentioned. By using a compound in which one or more hydrogen atoms of these compounds are substituted with a silicon-containing functional group, the effect of protecting the positive electrode is further improved, and a non-aqueous solvent, a lithium salt, and other additives It tends to be possible to further suppress oxidation and side reactions on the positive electrode and elution of the positive electrode active material component into the electrolyte. Thereby, the battery characteristics tend to be further improved. As the organic acid, a compound having at least one carboxylic acid moiety is preferable.

  The compound having one or more sulfonic acid moieties is not particularly limited. For example, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, butanesulfonic acid, acrylic acid sulfonic acid, vinylsulfonic acid, benzenesulfonic acid, alkylbenzenesulfonic acid , Toluenesulfonic acid, fluorosulfonic acid and the like.

The compound having at least one carboxylic acid moiety is not particularly limited, for example, acetic acid, trifluoroacetic acid, propionic acid, butyric acid, valeric acid, acrylic acid, methacrylic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, Examples include phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, malonic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, and itaconic acid. Among these, benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, malonic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, itaconic acid and the like are preferable, and adipic acid, itaconic acid, succinic acid, malon are preferable. More preferred are acids, fumaric acid, glutaric acid, benzoic acid, isophthalic acid, and terephthalic acid, which are dicarboxylic acids, adipic acid, itaconic acid, succinic acid, malonic acid, fumaric acid, glutaric acid, isophthalic acid, and terephthalic acid Are more preferred, with adipic acid, itaconic acid, succinic acid, isophthalic acid, and terephthalic acid being most preferred.
The effect of protecting the positive electrode is further improved by using a compound having one or more carboxylic acid moieties, and oxidation and side reactions of the nonaqueous solvent, lithium salt and other additives on the positive electrode, and positive electrode active material components There is a tendency that elution into the electrolyte can be further suppressed. This is because the carboxyl site tends to act with the metal of the positive electrode active material. In addition, a dicarboxylic acid having two carboxyl moieties in one molecule shows a higher effect.

(Acid amide)
The acid amide is not particularly limited, but examples thereof include N-alkyl substituted or unsubstituted acetamide and carboxylic acid amides represented by N-alkyl substituted or unsubstituted formamide; sulfonic acid amide, N-alkyl substituted or unsubstituted Examples thereof include phosphoric acid monoamide, N-alkyl-substituted or unsubstituted phosphoric acid diamide, and phosphoric acid amide represented by N-alkyl-substituted or unsubstituted phosphoric acid triamide. Among these, phosphoric acid amides such as N-alkyl-substituted carboxylic acid amides or N-alkyl-substituted phosphoric acid triamides are preferable. By using a compound in which one or more hydrogen atoms of the N-alkyl-substituted carboxylic acid amide or phosphoric acid amide are substituted with a silicon-containing functional group, the effect of protecting the positive electrode is further improved, and a non-aqueous solvent, There is a tendency that oxidation and side reaction of the lithium salt and other additives on the positive electrode and elution of the positive electrode active material component into the electrolytic solution can be further suppressed. This compound also has a function of removing unnecessary acid content in the battery. Thereby, the battery characteristics tend to be further improved.

(Amine)
Although it does not specifically limit as an amine, For example, a primary amine, a secondary amine, a tertiary amine, and a quaternary ammonium salt are mentioned. Among these, a secondary amine or a tertiary amine is preferable.

  Among inorganic acids, organic acids, acid amides and amines, inorganic acids or organic acids are preferable. By using a compound in which one or more hydrogen atoms of an inorganic acid or an organic acid are substituted with a silicon-containing functional group, oxidation and side reactions on a positive electrode of a nonaqueous solvent, a lithium salt, and an additive, and a positive electrode There exists a tendency for the ability to suppress the elution to the electrolyte solution of an active material component to be more excellent.

  The silicon compound of this embodiment may contain one or two or more inorganic acid, organic acid, acid amide, or amine sites.

(Silicon-containing functional group)
Although it does not specifically limit as a silicon-containing functional group, For example, the functional group which has one or more site | parts represented by -Si (R < ¹ >) (R < ² >) (R < ³ >) is mentioned. Here, one or more of R ¹ to R ³ is a halogen-substituted or unsubstituted, saturated or unsaturated, preferably a hydrocarbon group having 1 to 20 carbon atoms, two of R ¹ to R ³ The above is more preferably a halogen-substituted or unsubstituted, saturated or unsaturated, hydrocarbon group having 1 to 20 carbon atoms.

  The halogen-substituted or unsubstituted saturated or unsaturated hydrocarbon group is not particularly limited, and examples thereof include alkyl groups, alkenyl groups, alkynyl groups, allyl groups, alkoxy groups, alkylthio groups, N-substituted alkyl groups, and F-substituted alkyls. Group, F-substituted alkoxy group, vinyl group, acrylic group, methacryl group and the like, and alkyl group, alkenyl group, alkoxy group and F-substituted alkyl group are preferable.

Further, at least two of R ^{1 to} R ³ may be bonded to form a ring. In the case of forming a ring, for example, at least two of R ^{1 to} R ³ represent a halogenated or unsubstituted, saturated or unsaturated, common alkylene group.

Among R ^{1 to} R ³ , the functional group other than the halogen-substituted or unsubstituted saturated or unsaturated hydrocarbon group is not particularly limited, and examples thereof include a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a mercapto group, Examples thereof include a sulfide group.

  The silicon-containing compound is not particularly limited. For example, among the hydrogen atoms possessed by inorganic acids, organic acids, acid amides or amines, the remaining hydrogen atoms not substituted with silicon-containing functional groups are silicon-free functional groups. It may be a substituted compound.

(Functional group containing no silicon)
Although it does not specifically limit as a silicon-free functional group, For example, a halogen-substituted or unsubstituted, saturated or unsaturated C1-C20 hydrocarbon group is mentioned. Such hydrocarbon groups are not particularly limited, and examples thereof include alkyl groups, alkenyl groups, alkynyl groups, allyl groups, alkoxy groups, alkylthio groups, N-substituted alkyl groups, F-substituted alkyl groups, F-substituted alkoxy groups, vinyls. Group, acrylic group, methacryl group and the like.

  Further, a silicon-free functional group that replaces two or more hydrogen atoms may be bonded to form a ring. In the case of forming a ring, for example, two silicon-free functional groups represent a substituted or unsubstituted, saturated or unsaturated, common alkylene group.

  The silicon-containing compound is not particularly limited, but is preferably a compound in which one or more hydrogen atoms of an inorganic acid or an organic acid are substituted with a silicon-containing functional group, and includes an inorganic acid or a carboxylic acid containing boron or phosphorus. More preferable is a compound in which one or more hydrogen atoms are substituted with a silicon-containing functional group, and two or more hydrogen atoms of a boron or phosphorus-containing inorganic acid or carboxylic acid are substituted with a silicon-containing functional group. More preferred are compounds.

  Examples of such silicon-containing compounds include, but are not limited to, tris (trimethylsilyl) phosphoric acid, tris (trimethylsilyl) phosphorous acid, trimethylsilylpolyphosphoric acid, ethyl bis (trimethylsilyl) phosphonate, butyl bis (trimethylsilyl) phosphonate Allyl, bis (trimethylsilyl) phosphonate, vinyl bis (trimethylsilyl) phosphonate, tris (trimethylsilyl) boric acid, tris (triethylsilyl) phosphoric acid, trimethylsilylacetic acid, bis (trimethylsilyl) succinic acid, bis (trimethylsilyl) malonic acid, bis (Trimethylsilyl) adipic acid, bis (trimethylsilyl) isophthalic acid, bis (trimethylsilyl) terephthalic acid, bis (triethylsilyl) malonic acid, bis (triethylsilyl) adipic acid, Sus (triethylsilyl) itaconic acid, bis (triethylsilyl) fumaric acid, bis (trimethylsilyl) succinic acid, bis (trimethylsilyl) oxalic acid, N, O-bis (trimethylsilyl) acetamide, 1,3-bis (trimethylsiloxy)- Examples include 1,3-dimethyldisiloxane and trimethylsilyl isocyanate.

  The content of the silicon-containing compound in the nonaqueous electrolytic solution is not particularly limited, but is preferably 0.1% by mass to 20% by mass, and 0.1% by mass to 15% by mass with respect to 100% by mass of the nonaqueous electrolytic solution. % Is more preferable, and 0.5% by mass to 10% by mass is more preferable. When this content is within the above range, it tends to be possible to obtain a battery that is more excellent in oxidation resistance and has a higher positive electrode potential and battery voltage. The content of the silicon-containing compound can be measured, for example, by nuclear magnetic resonance spectroscopy (NMR spectroscopy), gas chromatography, or the like, even in a state where it is mixed in the electrolytic solution. In nuclear magnetic resonance spectroscopy, silicon, boron, phosphorus, or the like can be selected as a measurement nuclide.

[Hydrofluoric acid]
Moreover, the non-aqueous electrolyte according to the present embodiment may contain hydrofluoric acid. The content of hydrofluoric acid is preferably 0.5 to 50 ppm by mass, more preferably 1 to 30 ppm by mass, and even more preferably 2 to 20 ppm by mass. When the content of hydrofluoric acid is in the above range, continuous repair and formation of the SEI film tend to be easier.

(water)
The nonaqueous electrolytic solution according to the present embodiment preferably does not contain moisture, but may contain a very small amount of moisture as long as the solution of the problem of the present embodiment is not hindered. Such water content is preferably 0 to 100 ppm by mass, more preferably 1 to 50 ppm by mass, and even more preferably 1 to 30 ppm by mass with respect to the total amount of the non-aqueous electrolyte.

[Separator]
In this embodiment, a nonaqueous electrolyte battery such as a lithium ion battery includes a separator between the positive electrode and the negative electrode. As the separator, an insulating thin film having high ion permeability and excellent mechanical strength is selected.

  In the separator according to the present embodiment, an inorganic layer is formed on one or both surfaces of the base film. The material of the base film before forming the inorganic layer is not particularly limited, and examples thereof include ceramic, glass, resin, and cellulose. The resin may be a synthetic resin or a natural resin (natural polymer), and may be an organic resin or an inorganic resin. From the viewpoint of excellent performance as a separator, Organic resins are preferably used.

  Although it does not specifically limit as organic resin, For example, heat resistant resins, such as polyolefin, polyester, polyamide, liquid crystal polyester, and aramid, are mentioned. As the polyolefin, polyethylene, polypropylene, or a copolymer or polymer alloy containing them is used.

  Moreover, it does not specifically limit as inorganic resin, For example, a silicone resin etc. are mentioned.

The material of the base film is preferably ceramic and glass from the viewpoint of heat resistance, and polyester, polyamide, liquid crystal polyester, aramid, and cellulose are preferable from the viewpoint of handling and heat resistance. Polyolefin is preferred from the viewpoints of cost, processability, and high-temperature shutdown performance. Among these materials, when a resin is employed, it may be a homopolymer or a copolymer, and a mixture of a plurality of types of resins and an alloy may be used.
When ceramic or glass is used for the base film, it may be substantially the same as or different from the formed inorganic layer.
A case where polyolefin is used as the base film will be described. From the viewpoint of shutdown performance and the like, it is preferably formed of a polyolefin resin composition in which the polyolefin resin occupies 50% by mass or more and 100% by mass or less of the film constituents, and the proportion of the polyolefin resin is 60% by mass or more and 100% by mass or less. It is more preferable that it is 70 mass% or more and 100 mass% or less.
The polyolefin resin is not particularly limited, and examples thereof include homopolymers such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene, copolymers, or multistage polymers. Is mentioned. Moreover, these polyolefin resins may be used independently or may be used in mixture of 2 or more types. Specific examples of the polyolefin resin include low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, ultrahigh molecular weight polyethylene, isotactic polypropylene, atactic polypropylene, ethylene-propylene random copolymer, polybutene, An ethylene propylene rubber etc. can be mentioned.
From the viewpoint of shutdown properties and high strength, it is preferable to use a resin composition mainly composed of high-density polyethylene as the polyolefin resin.
Moreover, it is preferable that it is a resin composition of a polypropylene and other resin from a heat resistant viewpoint.

  Further, the base film may be a laminated body in which films of a plurality of materials are laminated. When the separator is a laminate, the material of each layer may be the same or different.

  In the case of manufacturing a film of a laminated body, it may be formed in order by repeating the formation of one layer on another layer, that is, sequentially multilayered, and a plurality of films prepared separately are bonded together. Thus, a laminate may be produced.

  Examples of the base membrane form in the present embodiment include a synthetic resin microporous membrane manufactured by forming a synthetic resin, a fiber spun from a synthetic resin or a natural polymer, a woven fabric processed from glass fiber or ceramic fiber. , Nonwoven fabrics, knitted fabrics, papermaking, and films prepared by arranging fine particles of synthetic resin, ceramic particles and glass.

The separator in the present embodiment forms an inorganic layer on the film surface. By containing an inorganic substance, a battery having excellent durability can be achieved even when the battery is driven at a high voltage, and it contributes to reinforcement of the film and improvement of heat resistance. The inorganic layer may be on at least one side of the film surface, or may be on both sides. Even when there are inorganic layers on both sides, the types and amounts of the inorganics on both sides may not be the same. In addition, it is necessary to include an inorganic layer on the surface of the separator that faces the negative electrode. When the amount of inorganic material on both sides of the separator is not the same, it is preferable that more inorganic material is present on the surface facing the negative electrode. Since the inorganic material on the separator works to improve the battery performance by acting on the metal deposited on the negative electrode surface and the gas generated from the negative electrode surface, the presence of a large amount of inorganic material on the negative electrode facing surface has a higher effect. thinking. In addition, it is excellent in the point that the handlinability of a film | membrane becomes favorable when an inorganic layer exists on both surfaces of a separator substantially equally. Further, since the entire base film is protected with an inorganic substance, a film that contributes to further improvement in safety and reliability is formed. On the other hand, when there is an inorganic layer only on one side, or when there is a difference in the amount of inorganic matter on both sides, it is easy to make a thin film, and it is easy to form a film with high output characteristics. Further, more electrodes can be put in the battery outer package, and a film contributing to high capacity is formed.
Although the separator of this embodiment does not limit the number of coating surfaces, it is preferable from a viewpoint of high capacity | capacitance and high output that there exists a difference in the coating amount of single-sided coating or both surfaces.
The shape of the inorganic substance is not limited, and may be particulate, fibrous, plate-shaped, or spindle-shaped.
The kind of the inorganic substance is not particularly limited as long as it does not inhibit charging / discharging of the lithium ion battery, but those having a high melting point and electrical insulation are preferable. Inorganic particles include metal hydroxides such as aluminum hydroxide, magnesium hydroxide, calcium hydroxide, chromium hydroxide, zirconium hydroxide, nickel hydroxide, boron hydroxide; silica, alumina, titania, zirconia, magnesia, ceria , Yttria, zinc oxide, metal oxides such as iron oxide and ITO; metal nitrides such as silicon nitride, titanium nitride, boron nitride and aluminum nitride; carbonates such as calcium carbonate and magnesium carbonate; barium sulfate, aluminum sulfate and sulfuric acid Sulfates such as calcium; calcium silicate, magnesium silicate, talc, kaolin, kaolinite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amicite, bentonite, apatite, zeolite, boehmite, mullite, spinel, diel Ito, nacrite, halloysite, pyrophyllite, clay minerals such as diatomaceous earth, silica sand, fluorides such as calcium fluoride and barium fluoride, carbon materials such as carbon black and graphite; silicon carbide, potassium titanate, titanium Examples include barium acid, silicon, diamond, and glass fiber. These inorganic substances are used alone or in combination of two or more. A plurality of the same kind of inorganic substances having different shapes and properties can be used in combination.
From the viewpoint of electrical and thermal stability, the inorganic substance is preferably a metal oxide, metal hydroxide, carbonate, sulfate or clay mineral, more preferably a metal oxide, carbonate or clay mineral, and a metal oxide. Or a clay mineral is more preferable. Among metal oxides or clay minerals, compounds containing aluminum are preferred. In consideration of availability, calcined kaolin and boehmite are preferably used.
The shape of the inorganic substance is not particularly limited, and various shapes such as a spherical shape, a plate shape, a needle shape, and a spindle shape can be used. From the viewpoint of short circuit prevention, plate-like particles are preferably used, and from the viewpoint of ion permeability, a polyhedral shape having a plurality of faces, a columnar shape, and a spindle shape are preferably used.
Moreover, the surface of the inorganic substance may be surface-treated. For example, a coupling agent such as a silane coupling agent may be used, or a hydrophilic or hydrophobic treatment may be performed. By performing such treatment, it is possible to control the adhesion between the inorganic material and the base film or binder and the cohesiveness between the inorganic materials.
The average primary particle diameter of the inorganic substance in the present embodiment is preferably 1 nm or more and 15 μm or less, more preferably 10 nm or more and 10 μm or less, and further preferably 30 nm or more and 5 μm or less.
In addition, in the layer actually formed in the separator, the primary particles are often agglomerated secondary particles. Secondary particles have a particle size of about 3 to 30 times that of primary particles.
When the average particle diameter of the inorganic material is in the above range, it has heat resistance and voltage resistance such as suppression of thermal shrinkage under high temperature and high voltage environment regardless of the thickness of the base film and the pore structure.
In addition, as a method for controlling the particle size of the inorganic material, there is a method of reducing the particle size by pulverizing the inorganic material using a ball mill, a bead mill, a jet mill or the like.
The proportion of the inorganic material in the present embodiment in the base film can be determined from the viewpoints of the binding property of the inorganic material, the permeability of the base film, heat resistance, etc., but is 50% by mass or more and less than 100% by mass. It is preferable that
The separator of this embodiment may have an organic substance in addition to the inorganic substance. Examples of the organic material include organic binders used for forming an inorganic layer. When forming the inorganic porous layer on the surface of the separator, it is preferable to include an organic binder. The organic binder is not particularly limited, and an organic binder that is electrochemically stable and insoluble in the electrolytic solution under the use conditions of the lithium ion battery is used. Examples of organic binders include polyolefins such as polyethylene and polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymers, fluorine-containing polymers such as fluorine rubber, polyvinyl acetate, polyvinyl alcohol, and polyvinyl butyral. (PVB) rubbers, ethylene-acrylic acid ester copolymers, methacrylic acid ester-acrylic acid ester copolymers, styrene-acrylic acid ester copolymers, acrylic acid esters such as acrylonitrile-acrylic acid ester copolymers , Styrene-butadiene rubber (SBR) and its hydride, acrylonitrile-butadiene-styrene copolymer and its hydride, ethyl cellulose, methyl cellulose, carboxymethyl Cellulose derivatives such as cellulose (CMC) and hydroxyethyl cellulose (HEC), polyphenylene ether, polysulfone, polyethersulfone, polyphenylene sulfide, polyetherimide, polyamideimide, polyamide, polyester, polyvinylpyrrolidone (PVP), crosslinked acrylic resin, polyurethane, Although an epoxy resin etc. are mentioned, the heat resistant binder which has a heat resistant temperature of 150 degreeC or more is especially preferable, and the heat resistant binder which has a heat resistant temperature of 180 degreeC or more is used more preferably. As the organic binder, those exemplified above may be used alone or in combination of two or more.
As the organic binder of this embodiment, a latex binder can also be used. Latex binders are emulsion polymerized from aliphatic conjugated diene monomers, unsaturated carboxylic acid monomers, and other monomers copolymerizable with these from the viewpoints of electrochemical stability and binding properties. What is obtained is preferable. Emulsion polymerization can be performed by a conventional method.
Examples of the conjugated diene compound include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, and 2-chloro-1,3-butadiene substituted linear conjugated pentadienes. , Substituted and side chain conjugated hexadienes, and the like.
Examples of the unsaturated carboxylic acid monomer include mono- or dicarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, and acrylic acid and methacrylic acid are particularly preferable.
The inorganic layer or the layer containing the inorganic and organic substances in the present embodiment may further contain materials other than those described above. Moreover, it does not prevent that the inorganic substance is contained in the separator. In order to improve the mechanical strength and heat resistance of the separator, the separator may contain an inorganic substance or an organic substance other than the separator base film.

[Positive electrode]
The positive electrode functions as the positive electrode of the lithium ion secondary battery, and is not particularly limited as long as it contains Co, and a known one can be used. The positive electrode contains one or more selected from the group consisting of materials capable of inserting and extracting lithium ions as a positive electrode active material.

As the positive electrode active material, for example,
Following formula (3):
LiCо _1-u Me _u O ₂ (3)
{In the formula, Me represents one or more selected from the group consisting of transition metals excluding Co, and u is a number in the range of 0.1 ≦ u ≦ 0.9. }
An oxide represented by
Following formula (4):
_{zLi 2 McO 3 - (1-} z) LiMdO 2 (4)
{In the formula, Mc and Md each independently represent one or more selected from the group consisting of transition metals, one or both of which contain Co, and z is 0.1 ≦ z ≦ A number in the range of 0.9. }
A composite oxide represented by
Following formula (5):
LiMb _1-y Co _y PO ₄ (5)
{In the formula, Mb represents one or more selected from the group consisting of transition metals, and y is a number in the range of 0 ≦ y ≦ 0.9. }
And a compound represented by the following formula (6):
Li ₂ Mf _1-y Co _y PO ₄ F (6)
{Wherein Mf represents one or more selected from the group consisting of transition metals, and y is a number in the range of 0 ≦ y ≦ 0.9. }
A compound represented by
It is preferably at least one selected from the group consisting of These positive electrode active materials tend to be more excellent in structural stability.

The oxide represented by the formula (3) may be a layered oxide positive electrode active material. The layered oxide positive electrode active material is not particularly limited, for example, LiCoO ₂ or the following formula (3a):
_{LiMn 1-vw Co v Ni w} O 2 (3a)
{Wherein v is a number within the range of 0.1 ≦ v ≦ 0.4, and w is a number within the range of 0.1 ≦ w ≦ 0.8. }
The oxide represented by these is preferable.

The layered oxide represented by the formula (3a) is not particularly limited. For example, LiMn _1/3 Co _1/3 Ni _1/3 O ₂ , LiMn _0.1 Co _0.1 Ni _0.8 O ₂ , LiMn _0.3 Co _0.2 Ni _0.5 O _{2 and the} like can be mentioned. By using the compound represented by the formula (8), the stability of the positive electrode active material tends to be more excellent. The compound represented by Formula (3) is used individually by 1 type or in combination of 2 or more types.

The composite oxide represented by the formula (4) may be a composite layered oxide. Although it does not specifically limit as a composite layered oxide, For example, following formula (4a):
_{zLi 2 MnO 3 - (1-} z) LiNi a Mn b Co c O 2 (4a)
{Wherein z is a number within a range of 0.3 ≦ z ≦ 0.7, a is a number within a range of 0.2 ≦ a ≦ 0.6, and b is 0 .2 ≦ b ≦ 0.6, c is a number in the range of 0.05 ≦ c ≦ 0.4, and a, b and c are a + b + c = 1. Satisfy the relationship. }
A composite oxide represented by

  In Formula (4a), 0.4 ≦ z ≦ 0.6, a + b + c = 1, 0.3 ≦ a ≦ 0.4, 0.3 ≦ b ≦ 0.4, 0.2 ≦ c ≦ 0.3 A certain complex oxide is more preferable. By using the composite oxide represented by the formula (4), the stability of the positive electrode active material tends to be more excellent. The composite layered oxide represented by the formula (4) is within a range of 10 mol% or less with respect to the total number of moles of Mn, Ni and Co atoms from the viewpoint of stability of the positive electrode active material, electronic conductivity and the like. In addition to the above structure, a transition metal or a transition metal oxide may be further contained. The composite oxide represented by the formula (4) is used singly or in combination of two or more.

The compound represented by the formula (5) may be an olivine type positive electrode active material. Although it does not specifically limit as an olivine type positive electrode active material, For example, following formula (5a):
LiMh _1-yz Fe _y Co _z PO ₄ (5a)
{Wherein y is a number in the range of 0.05 ≦ y + z ≦ 0.8, and Mh represents a transition metal such as Mn or Ni. } Or the following formula (5b):
LiMh _1-y Co _y PO ₄ (5b)
{Wherein y is a number in the range of 0.05 ≦ y ≦ 0.8, and Mh represents a transition metal such as Mn or Ti. }
The compound represented by these is preferable.

  By using the compound represented by Formula (5), the stability and electronic conductivity of the positive electrode active material tend to be superior. The compound represented by Formula (5) is used individually by 1 type or in combination of 2 or more types.

The compound represented by the formula (6) may be a fluorinated olivine type positive electrode active material. The fluoride olivine-type positive electrode active material is not particularly limited, for example, Li ₂ CoPO ₄ F is used. By using the compound represented by Formula (6), the stability of the positive electrode active material tends to be superior. The compound represented by the formula (6) has a structure other than the above structure in a range of 10 mol% or less with respect to the total number of moles of Fe and Co atoms from the viewpoint of stability of the positive electrode active material, electronic conductivity, and the like. Further, a transition metal or a transition metal oxide may be contained. The compound represented by Formula (6) is used individually by 1 type or in combination of 2 or more types.

A spinel positive electrode active material represented by the following formula (8) can also be used.
_{LiMn 2-x - y Ma x} Co y O 4 (8)
{In the formula, Ma represents one or more selected from the group consisting of transition metals, and x is a number in the range of 0.2 ≦ x + y ≦ 0.7. }
Although it does not specifically limit as a spinel type positive electrode active material, following formula (8a):
LiMn _2-xy Ni _x Co _y O ₄ (8a)
{Wherein x is a number within a range of 0.2 ≦ x + y ≦ 0.7. }
An oxide represented by the following formula (8b):
LiMn _2-xy Ni _x Co _y O ₄ (8b)
{Wherein x is a number within a range of 0.3 ≦ x + y ≦ 0.6. }
The oxide represented by is used.

  From the viewpoint of stability of the positive electrode active material, electronic conductivity, and the like, the spinel oxide represented by the formula (8) is within a range of 10 mol% or less with respect to the number of moles of Mn atoms. Further, a transition metal or a transition metal oxide may be contained. The compound represented by Formula (8) is used individually by 1 type or in combination of 2 or more types.

  The number average particle diameter (primary particle diameter) of the positive electrode active material is preferably 0.05 μm to 100 μm, more preferably 1 μm to 10 μm. This number average particle diameter is obtained by randomly extracting 100 particles observed with a transmission electron microscope, analyzing them with image analysis software, and calculating the arithmetic average thereof. In this case, when the number average particle diameter differs between measurement methods for the same sample, a calibration curve created for the standard sample may be used.

In the lithium ion secondary battery of this embodiment, such positive electrode active materials can be used alone or in combination of two or more. Also, as the positive electrode active material, 4.4V (vsLi / Li ⁺⁾ and the positive electrode active material having a 10 mAh / g or more discharge capacity than the potential, 4.4V (vsLi / Li ⁺⁾ or more potential 10 mAh / g A positive electrode active material having no discharge capacity as described above can also be used in combination. The positive electrode active material that does not have a discharge capacity of 10 mAh / g or more at a potential of 4.4 V (vsLi / Li ⁺ ) or more is not particularly limited, and examples thereof include LiFePO ₄ .

The discharge capacity of the positive electrode active material used in the present embodiment is preferably 10 mAh / g or more, more preferably 15 mAh / g or more, and more preferably 20 mAh / g at a potential of 4.4 V (vsLi / Li ⁺ ) or more. More preferably, the above has. When the discharge capacity of the positive electrode active material is within the above range, the battery can be driven at a high voltage to achieve a high energy density. In addition, even when driving at a low voltage, a battery with sufficient capacity and higher reliability and safety can be achieved. The discharge capacity of the positive electrode active material can be measured by the method described in the examples.
In the battery of the present embodiment, the battery whose upper limit voltage for charging exceeds 4.1 V is preferable, preferably 4.153 V or higher, and more preferably 4.3 V or higher.
Here, 4.4 V and a positive electrode active material having a 10 mAh / g or more discharge capacity (vsLi / Li ⁺⁾ or more potential, 4.4V (vsLi / Li ⁺⁾ of the lithium ion secondary battery or a potential It is a positive electrode active material capable of causing charge and discharge reactions as a positive electrode, and has a discharge capacity at a constant current discharge of 0.1 C of 10 mAh or more with respect to 1 g of mass of the active material. Therefore, it is sufficient that the positive electrode active material has a discharge capacity of 10 mAh / g or more at a potential of 4.4 V (vsLi / Li ⁺ ) or more, and a discharge capacity at a potential of 4.4 V (vsLi / Li ⁺ ) or less. There is no problem even if it has.

(Lithium standard positive electrode potential at full charge)
The positive electrode potential of the lithium reference when fully charged lithium ion secondary battery according to the present embodiment is preferably 4.1V (vsLi / Li ⁺⁾ or higher, more preferably 4.2V (vsLi / Li ⁺⁾ or higher, 4 More preferably, 3 V (vsLi / Li ⁺ ) or more. When the positive electrode potential at full charge is the above, the charge / discharge capacity of the positive electrode active material of the lithium ion secondary battery can be used efficiently, and the energy density of the lithium ion secondary battery tends to be further improved. is there. The lithium-based positive electrode potential at the time of full charge can be controlled by controlling the voltage of the battery at the time of full charge.

Lithium-based positive electrode potential at full charge is to disassemble a fully charged lithium ion secondary battery in an Ar glove box, take out the positive electrode, reassemble the battery using metallic lithium as the counter electrode, and measure the voltage Can be measured easily.
Further, when a carbon negative electrode active material is used for the negative electrode, the potential of the lithium ion secondary battery at the time of full charge (Va) since the potential of the carbon negative electrode active material at the time of full charge is 0.05 V (vsLi / Li ⁺ ) ) To 0.05V, the potential of the positive electrode at full charge can be easily calculated. For example, in a lithium ion secondary battery using a carbon negative electrode active material for the negative electrode, when the voltage (Va) of the lithium ion secondary battery at full charge is 4.4 V, the potential of the positive electrode at full charge is It can be calculated as 4.4V + 0.05V = 4.45V.

(Method for producing positive electrode active material)
The positive electrode active material can be produced by the same method as that for producing a general inorganic oxide. The method for producing the positive electrode active material is not particularly limited. For example, inorganic oxide is obtained by firing a mixture in which metal salts (for example, sulfate and / or nitrate) are mixed at a predetermined ratio in an atmosphere containing oxygen. And a method of obtaining a positive electrode active material containing a product. In addition, a carbonate and / or hydroxide salt is allowed to act on a solution in which the metal salt is dissolved to precipitate a hardly soluble metal salt, which is extracted and separated into a lithium source and lithium carbonate and / or hydroxide as a lithium source. After lithium is mixed, a method of obtaining a positive electrode active material containing an inorganic oxide by firing in an atmosphere containing oxygen can be given.

(Production method of positive electrode)
Here, an example of the manufacturing method of a positive electrode is shown below. First, a paste containing a positive electrode mixture is prepared by dispersing, in a solvent, a positive electrode mixture obtained by adding a conductive auxiliary agent, a binder, and the like to the positive electrode active material as necessary. Next, this paste is applied to a positive electrode current collector, dried to form a positive electrode mixture layer, and the positive electrode mixture layer is pressurized as necessary to adjust the thickness, whereby a positive electrode can be produced. .

  Although it does not specifically limit as a positive electrode electrical power collector, For example, what is comprised with metal foil, such as aluminum foil or stainless steel foil, is mentioned.

[Negative electrode]
A negative electrode will not be specifically limited if it acts as a negative electrode of a lithium ion secondary battery, A well-known thing may be used. The negative electrode contains one or more materials selected from the group consisting of a material capable of inserting and extracting lithium ions as a negative electrode active material and metallic lithium. Such a negative electrode preferably contains, as a negative electrode active material, at least one selected from the group consisting of metallic lithium, carbon materials, silicon materials, materials containing elements capable of forming an alloy with lithium, and lithium-containing compounds. Among these, it is more preferable to contain one or more materials selected from the group consisting of metallic lithium, carbon materials, silicon materials, and materials containing elements capable of forming an alloy with lithium. By using such a negative electrode active material, the battery capacity tends to be further improved.

  The carbon material is not particularly limited. For example, hard carbon, soft carbon, artificial graphite, natural graphite, graphite, pyrolytic carbon, coke, glassy carbon, fired body of organic polymer compound, mesocarbon microbead, carbon Examples thereof include fibers, activated carbon, graphite, carbon colloid, and carbon black. Although it does not specifically limit as coke, For example, pitch coke, needle coke, and petroleum coke are mentioned. Further, the fired body of the organic polymer compound is not particularly limited. For example, a polymer material such as a phenol resin or a furan resin is fired at a suitable temperature and carbonized. In the present embodiment, a battery employing metallic lithium as the negative electrode active material is also included in the lithium ion secondary battery.

  Although it does not specifically limit as a silicon material, For example, a crystalline silicon compound, an amorphous silicon compound, an organic silicon compound, an alloy of silicon and a metal, etc. are mentioned. In addition, various forms of silicon materials such as nano silicon materials and fibrous silicon materials can be used.

  Furthermore, the material containing an element capable of forming an alloy with lithium is not particularly limited. For example, the material may be a metal or a semimetal alone, an alloy, or a compound. It may have at least a part of one or two or more phases.

  In the present specification, the “alloy” includes an alloy having one or more metal elements and one or more metalloid elements in addition to an alloy composed of two or more metal elements. Further, the alloy may have a nonmetallic element as long as it has metal properties as a whole. In the structure of the alloy, a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or two or more of these coexist.

  Although it does not specifically limit as a metal element and a metalloid element, For example, titanium (Ti), tin (Sn), lead (Pb), aluminum, indium (In), silicon (Si), zinc (Zn), antimony ( Sb), bismuth (Bi), gallium (Ga), germanium (Ge), arsenic (As), silver (Ag), hafnium (Hf), zirconium (Zr) and yttrium (Y). Among these, metal elements and metalloid elements of Group 4 or Group 14 in the long-period periodic table are preferable, and titanium, silicon, and tin are more preferable.

  Although it does not specifically limit as an alloy of silicon, For example, as a 2nd element other than silicon, tin, magnesium, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony And those having one or more elements selected from the group consisting of chromium.

  Although it does not specifically limit as an alloy of tin, For example, as a 2nd structural element other than tin, silicon, magnesium (Mg), nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium (Ti) And one having at least one element selected from the group consisting of germanium, bismuth, antimony and chromium (Cr).

  The titanium compound, the tin compound, and the silicon compound are not particularly limited, and examples thereof include those having oxygen (O) or carbon (C). In addition to titanium, tin, or silicon, the second compound described above is used. It may have a constituent element.

  Although it does not specifically limit as a lithium containing compound, For example, the same thing as what was illustrated as a positive electrode material can be used.

  A negative electrode active material is used individually by 1 type or in combination of 2 or more types.

  The number average particle diameter (primary particle diameter) of the negative electrode active material is preferably 0.1 μm to 100 μm, more preferably 1 μm to 10 μm. The number average particle size of the negative electrode active material is measured in the same manner as the number average particle size of the positive electrode active material.

(Method for producing negative electrode)
A negative electrode is obtained as follows, for example. That is, first, a negative electrode mixture-containing paste is prepared by dispersing, in a solvent, a negative electrode mixture obtained by adding a conductive additive, a binder, and the like to the negative electrode active material as necessary. Next, the negative electrode mixture-containing paste is applied to a negative electrode current collector and dried to form a negative electrode mixture layer, which is pressurized as necessary to adjust the thickness, whereby a negative electrode can be produced. .

  Here, the solid content concentration in the negative electrode mixture-containing paste is preferably 30 to 80% by mass, and more preferably 40 to 70% by mass.

  Although a negative electrode collector is not specifically limited, For example, metal foil, such as copper foil, nickel foil, or stainless steel foil, is mentioned.

[Conductive aid or binder used to produce positive and negative electrodes]
Although it does not specifically limit as a conductive support agent used as needed at the time of preparation of a positive electrode and a negative electrode, For example, carbon black represented by graphite, acetylene black, and ketjen black, and carbon fiber are mentioned. The number average particle diameter (primary particle diameter) of the conductive assistant is preferably 0.1 μm to 100 μm, more preferably 1 μm to 10 μm. The number average particle size of the conductive additive is measured in the same manner as the number average particle size of the positive electrode active material. The binder is not particularly limited, and examples thereof include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid, styrene butadiene rubber, and fluorine rubber.

<Method for manufacturing lithium ion secondary battery>
A general method may be used as a method for manufacturing the lithium ion secondary battery in the present embodiment, and is not particularly limited. For example, the following method can be selected.

  First, a battery structure is produced by housing a laminate produced using a positive electrode, a negative electrode, and a separator in a battery case (exterior). And a battery can be produced by injecting the non-aqueous electrolyte of the present embodiment into it.

  For example, the laminated body is formed by alternately winding a positive electrode and a negative electrode in a laminated state with a separator interposed therebetween to form a laminated structure having a wound structure, or bending them, laminating a plurality of layers, etc. It can produce by shape | molding into the laminated body in which a separator interposes between the some positive electrode and negative electrode which were laminated | stacked. Here, when forming a laminated body, it arrange | positions so that the surface which opposes a negative electrode among separators may necessarily have a layer containing an inorganic substance. In addition, when the amount of inorganic matter is different on both sides of the separator, an inorganic layer may be arranged on either side, but it should be installed so that the amount of inorganic matter on the surface facing the negative electrode is increased. Is preferred. By installing the separator in this way, the causes of performance degradation in lithium ion secondary batteries with high charging potential and voltage include gas components generated at the negative electrode and metal deposited on the negative electrode surface, and the performance degradation Can be reduced.

  The battery manufacturing method according to the present embodiment may include a step of pressurizing or depressurizing the inside of the battery. The method of pressurization and pressure reduction is not particularly limited, and the heating and the pressure reduction and pressurization may be performed simultaneously or separately. By passing through these steps, the impregnation property of the electrolyte into the electrode and separator of the battery structure may be improved, or the battery manufacturing time may be shortened.

  After passing through the above steps, if necessary, the remaining members are incorporated into the battery structure, and if the battery case (exterior) is not completely sealed (sealed), the battery is sealed. Can be obtained. If necessary, after passing through the above-described steps, the shape of the battery may be adjusted by removing an excess part of the battery, or the battery may be retightened or resealed.

  The shape of the battery in the present embodiment is not particularly limited, and examples thereof include a cylindrical shape, an oval shape, a rectangular tube shape, a button shape, a coin shape, a flat shape, and a laminate shape. Among these, a coin type, a cylindrical type, a rectangular tube type, a flat type and a laminate type are preferable, and a coin type, a cylindrical type, a flat type and a laminate type are more preferable. The battery having such a shape can further enhance the affinity between the electrolytic solution and the battery structure, expresses various performances of the electrolytic solution in the present embodiment to a higher level, and is relatively easy to manufacture the battery. Easy. Also, the size of the battery is not particularly limited, and a structure in which a plurality of batteries are stacked or arranged can be used in combination with many kinds of batteries. In addition, a laminated battery has a battery case (exterior) configured by laminating an aluminum film and a resin like an aluminum laminate material from the viewpoints of lightness, durability, handleability, and cost. More preferably it is.

  The lithium ion secondary battery of this embodiment can function as a battery by initial charge. Although there is no restriction | limiting in particular about the method of the initial charge in this embodiment, It is preferable that initial charge is performed at 0.001C-0.5C, It is more preferable to be performed at 0.002C-0.3C, 0.003C More preferably, it is carried out at ~ 0.2C. In addition, it is also preferable that the initial charging is performed via the constant voltage charging in the middle. In addition, the constant current which discharges rated capacity in 1 hour is 1C. By setting the voltage range in which the lithium salt is involved in the electrochemical reaction to be long, a SEI (Solid Electrolyte Interface) film is formed on the electrode surface, which has an effect of suppressing an increase in internal resistance including the positive electrode. It is very effective to perform the first charge in consideration of such an electrochemical reaction.

  In addition, the non-aqueous secondary battery of this embodiment can also be used by connecting in series or in parallel.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples. Various characteristics of the nonaqueous secondary battery were measured and evaluated as follows.

(1) Preparation of non-aqueous electrolyte solution Non-aqueous electrolyte solution obtained by mixing ethylene carbonate and ethyl methyl carbonate as a non-aqueous solvent at a volume ratio of 3: 7, and adding LiPF ₆ to 1M with respect to the non-aqueous solvent. (A) was prepared. An electrolyte solution (B) was obtained by adding 2.0 parts by weight of tris (trimethylsilyl) phosphate to 100 parts by weight of the electrolyte solution (A).

(2) Manufacture of separator 1
A separator made of a polyolefin resin in which polyethylene and polypropylene are blended at a ratio of 95: 5 and having a film thickness of 17 μm and a porosity of 60% is used as a base film (D). A wet kaolin mainly composed of knight (Al ₂ Si ₂ O ₅ (OH) ₄ ) is applied at a high temperature, and an average particle size of 1.8 μm is applied to form a porous layer having a thickness of 7 μm on (D). The formed separator (d) was obtained. Application of the calcined kaolin is 95.0 parts by mass of calcined kaolin, 5.0 parts by mass of acrylic latex (solid concentration 40%, average particle size 220 nm, minimum film forming temperature 0 ° C. or less), ammonium polycarboxylate aqueous solution (San Nopco) (Manufactured by SN Dispersant 5468) 0.5 parts by mass was uniformly dispersed in 180 parts by mass of water to prepare a coating solution, which was applied to the surface (one side) of the base film and dried.

  (D) and (d) were punched into a disk shape having a diameter of 25 mm, and the separators (D1) and (d1) were punched into 3 cm × 4 cm to obtain separators (D2) and (d2).

(3) Manufacture of separator 2
Firing kaolin was applied to both sides of the base film to obtain a separator (e) having a coating porous layer thickness of 10 μm. (E) was punched into a disk shape having a diameter of 25 mm (e1), and 3 cm × 4 cm was punched (e2).

(4) Preparation of positive electrode Lithium cobaltate was used as the positive electrode active material, acetylene black and PVDF binder were mixed, and an NMP solvent was added to prepare a slurry. The prepared slurry was applied to an aluminum foil (thickness: 15 μm), and the solvent was dried, followed by roll press treatment to obtain a positive electrode plate. The obtained positive electrode plate was punched into a disk shape having a diameter of 16 mm, and the positive electrode (a1) and the positive electrode plate were punched into a rectangular shape of 3 cm × 4 cm to obtain a positive electrode (a2).
In addition, using a composite oxide of lithium, cobalt, nickel and manganese (LiNi _1/3 Mn _1/3 Co _1/3 O ₂ ) as a positive electrode active material, a positive electrode was produced in the same manner as described above, and a disc-shaped positive electrode having a diameter of 16 mm A plate (b1) and a 3 cm × 4 cm rectangular positive plate (b2) were obtained.

(5) Preparation of negative electrode Using graphite powder (trade name “OMAC1.2H / SS” manufactured by Osaka Gas Chemical Co., Ltd.) as a negative electrode active material, other graphite powder (trade name “SFG6” manufactured by TIMCAL), Styrene butadiene rubber and carboxymethyl cellulose were mixed and a slurry was prepared with an aqueous solvent. The prepared slurry was applied to one side of a copper foil (thickness: 18 μm), the solvent was removed by drying, and then rolled with a roll press to obtain a negative electrode plate. The obtained negative electrode sheet was punched into a disk shape having a diameter of 16 mm and punched into a negative electrode (c1) and a rectangular shape of 3 cm × 4 cm to obtain a negative electrode (c2).

(6) Production of lithium ion battery 1
The positive electrode (a1) or (b1) and the negative electrode (c1) were superimposed on both sides of the separator (d1) or (D1) produced as described above to obtain a laminate. This laminate was inserted into a disk-type battery case made of SUS. Next, 0.4 mL of the electrolytic solution was injected into the battery case, and the laminate was immersed in the electrolytic solution. Then, the battery case was sealed to produce a lithium ion secondary battery (small battery). This battery was kept in a thermostatic bath set at 25 ° C. for 24 hours, and the non-aqueous electrolyte was sufficiently adapted to the laminated body so that 1C = 6.0 mA. The produced battery was connected to a charge / discharge device (trade name “ACD-01” manufactured by Asuka Electronics Co., Ltd.), charged for 8 hours at a constant current of 0.2 C-constant voltage, and 3 at a constant current of 0.3 C. It was completed by initial conditioning by discharging to 0.0V. Charging was performed up to 4.35V.

(7) Manufacture of lithium-ion batteries 2
Electrode tabs were welded to the positive electrode (a2) or (b2) and the negative electrode (c2) on both sides of the separator (d2) or (D2) produced as described above to produce a laminate of the electrode and the separator. Next, the laminate was sandwiched between exterior bodies composed of a laminate of aluminum and a resin, and the three pieces were heat-sealed to obtain a laminate type battery. Next, 0.5 mL of the electrolytic solution (A) or (B) was injected into the battery case and the laminate was immersed in the electrolytic solution, and then the battery case was sealed to produce a lithium ion secondary battery. This battery was kept in a thermostat set at 25 ° C. for 24 hours, and the non-aqueous electrolyte solution was sufficiently adapted to the laminate so that 1C = 40.0 mA. The produced battery was connected to a charge / discharge device (trade name “ACD-01” manufactured by Asuka Electronics Co., Ltd.), charged for 8 hours at a constant current of 0.1 C-constant voltage, and 3 at a constant current of 0.3 C. It was completed by initial conditioning by discharging to 0.0V. The charging was performed up to 4.35V.

(8) Evaluation A charge / discharge cycle test was performed using the electrolytic solution obtained as described above. These evaluations were performed using a charge / discharge device ACD-01 (trade name) manufactured by Asuka Electronics Co., Ltd. and a thermostat PLM-63S (trade name) manufactured by Futaba Kagaku Co., Ltd.
[High temperature cycle test 1]
The battery was charged with a constant current of 1 C, reached 4.35 V, charged with a constant voltage of 4.35 V, and charged for a total of 1.5 hours. Thereafter, the battery was discharged to 3.0 V at a constant current of 1 C, and this was defined as one charge / discharge cycle. This charge / discharge cycle was carried out at 50 ° C., and the value of the discharge capacity at each cycle relative to the discharge capacity at the first cycle was calculated as the discharge capacity retention rate. The charge / discharge cycle was continued until the discharge capacity retention rate decreased to 80%, and the number of cycles at that time was determined.

Example 1
Using (d1) as the separator, (a1) as the positive electrode, and (c1) as the negative electrode, the separator was installed so that the inorganic coating surface was directed to the negative electrode side to produce a laminate. Next, using (B) as the electrolytic solution, a battery was produced according to the above-described method, and a high-temperature cycle test was performed. The results are shown in Table 1.
(Example 2)
The same operation as in Example 1 was performed except that (b1) was used as the positive electrode. The results are shown in Table 1.
(Example 3)
It implemented similarly to Example 1 except using (A) as electrolyte solution. The results are shown in Table 1.
Example 4
It implemented like Example 3 except using (e1) as a separator. The results are shown in Table 1.
(Comparative Example 1)
It implemented similarly to Example 1 except having installed so that the inorganic substance coating surface of a separator might face a positive electrode side. The results are shown in Table 1.
(Comparative Example 2)
It implemented like Example 1 except having used (D1) as a separator. The results are shown in Table 1.
(Comparative Example 3)
The same procedure as in Example 1 was performed except that (D1) was used as the separator and (A) was used as the electrolytic solution. The results are shown in Table 1.
(Example 5)
Using (d2) as a separator, (a2) as a positive electrode, and (c2) as a negative electrode, the separator was installed so that the inorganic coating surface was directed to the negative electrode side, to produce a laminate. Next, using (B) as the electrolytic solution, a battery was produced according to the above-described method, and a high-temperature cycle test was performed. The results are shown in Table 1.
(Example 6)
The same operation as in Example 5 was performed except that (b2) was used as the positive electrode. The results are shown in Table 1.
(Example 7)
It implemented similarly to Example 5 except using (A) as electrolyte solution. The results are shown in Table 1.
(Example 8)
It implemented like Example 5 except using (e2) as a separator. The results are shown in Table 1.
(Comparative Example 4)
It implemented like Example 5 except having installed so that the inorganic substance coating surface of a separator might face a positive electrode side. The results are shown in Table 1.
(Comparative Example 5)
The same operation as in Example 5 was performed except that (D2) was used as a separator. The results are shown in Table 1.
(Comparative Example 6)
The same operation as in Example 5 was performed except that (D2) was used as the separator and (A) was used as the electrolytic solution. The results are shown in Table 1.

Claims (11)

A positive electrode containing cobalt in the positive electrode active material;
A negative electrode,
A non-aqueous electrolyte,
A separator having a layer containing an inorganic substance on at least one side;
A lithium-ion secondary battery having a lithium-based positive electrode potential of 4.1 V (vsLi / Li ⁺ ) or higher when fully charged,
A lithium ion secondary battery in which an inorganic layer is present on the surface of the separator facing the negative electrode. A non-aqueous electrolyte and a non-aqueous solvent,
Lithium salt,
A silicon-containing compound in which one or more hydrogen atoms of one or more compounds selected from the group consisting of inorganic acids, organic acids, acid amides, and amines are substituted with silicon-containing functional groups;
including,
The lithium ion secondary battery according to claim 1.   In the silicon-containing compound, one or more hydrogen atoms of one or more compounds selected from the group consisting of an inorganic acid, a carboxylic acid, and a phosphoric acid amide formed by a bond of a base containing boron or phosphorus and hydrogen are silicon. The lithium ion secondary battery according to claim 2, wherein the lithium ion secondary battery is a silicon-containing compound substituted with a containing functional group. The lithium ion secondary according to any one of claims 2 to 3, wherein the silicon-containing compound is a compound having one or more sites represented by -Si (R ¹ ) (R ² ) (R ³ ). battery. (R ^{1 to} R ³ each independently represents an alkyl group, an alkenyl group, an alkoxy group, or an F-substituted alkyl group.) The non-aqueous electrolyte further includes the following formula (1):

{In the formula, M represents a phosphorus atom or a boron atom; when M is a phosphorus atom, w is 0 or 1, and when M is a boron atom, w is 0, R ¹ , R ² , and R ³ each independently represents an optionally substituted organic group having 1 to 10 carbon atoms, and R ⁴ and R ⁵ each independently represents an OH group, an OLi group, or an optionally substituted carbon number of 1; An alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms that may be substituted, a siloxy group having 3 to 10 carbon atoms, an aryl group having 6 to 15 carbon atoms, and an aryloxy group having 6 to 15 carbon atoms. A group selected from the group is shown. } And / or the following formula (2):

{Wherein R ¹ , R ² , and R ³ each independently represents an optionally substituted organic group having 1 to 10 carbon atoms, and R ⁶ represents an optionally substituted carbon number 1 -20 organic groups are shown. } The lithium ion secondary battery as described in any one of Claims 2-4 containing the compound represented by these.   The lithium ion secondary battery according to any one of claims 1 to 5, wherein the inorganic substance includes at least one member selected from the group consisting of metal oxides, metal hydroxides, carbonates, sulfates, and clay minerals. .   The lithium ion secondary battery according to claim 1, wherein the separator base film is an organic resin. The lithium ion secondary battery according to any one of claims 1 to 7, wherein a positive electrode potential based on lithium at a time of full charge exceeds 4.2 V (vsLi / Li ⁺ ). The positive electrode active material is
Following formula (3):
LiCо _1-u Me _u O ₂ (3)
{In the formula, Me represents one or more selected from the group consisting of transition metals excluding Co, and u is a number in the range of 0.1 ≦ u ≦ 0.9. }
An oxide represented by
Following formula (4):
_{zLi 2 McO 3 - (1-} z) LiMdO 2 (4)
{In the formula, Mc and Md each independently represent one or more selected from the group consisting of transition metals, one or both of which contain Co, and z is 0.1 ≦ z ≦ A number in the range of 0.9. }
A composite oxide represented by
Following formula (5):
LiMb _1-y Co _y PO ₄ (5)
{In the formula, Mb represents one or more selected from the group consisting of transition metals, and y is a number in the range of 0 ≦ y ≦ 0.9. }
And a compound represented by the following formula (6):
Li ₂ Mf _1-y Co _y PO ₄ F (6)
{Wherein Mf represents one or more selected from the group consisting of transition metals, and y is a number in the range of 0 ≦ y ≦ 0.9. }
A compound represented by
The lithium ion secondary battery as described in any one of Claims 1-8 which is 1 or more types chosen from the group which consists of.   The lithium ion secondary battery according to any one of claims 1 to 9, wherein an amount of an inorganic substance existing on a surface facing the positive electrode of the separator is equal to or less than an amount of an inorganic substance existing on a surface facing the negative electrode. 11. The lithium ion secondary battery according to claim 1, wherein the positive electrode active material has a discharge capacity of 10 mAh / g or more at a potential of 4.4 V (vsLi / Li ⁺ ) or more.