JPWO2015060156A1 - Additive for lithium ion secondary battery, electrode and electrolyte using the same, and lithium ion secondary battery - Google Patents

Abstract

The additive (D) for lithium ion secondary batteries of the present invention comprises a compound (C) having a bond (a) having a structure represented by the following general formula (1) and a group (b) containing a group 15 element. contains. [In general formula (1), R is a hydrogen atom or a C1-C12 organic group. ] [Chemical 1]

Description

The present invention relates to a battery additive useful for improving the safety of a lithium ion secondary battery, an electrode and an electrolytic solution using the same, and a lithium ion secondary battery.

Non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries are characterized by high voltage and high energy density, and thus are widely used in the field of portable information equipment, and their demand is rapidly expanding. Non-aqueous electrolyte secondary batteries are currently established as standard batteries for mobile information devices such as mobile phones and laptop computers.

It is known that in a non-aqueous electrolyte secondary battery, when an abnormality such as a short circuit occurs, when the battery temperature exceeds 200 ° C., active oxygen generated from the positive electrode reacts with the electrolyte to cause an exothermic reaction. As an electrolyte for a non-aqueous electrolyte secondary battery, an electrolyte such as lithium hexafluorophosphate (LiPF ₆ ) dissolved in a flammable solvent such as diethyl carbonate is generally used. Therefore, there is a risk of ignition of the electrolyte during heat generation, and there is an increasing interest in technologies that improve battery safety, such as adding a flame retardant to the electrolyte.

In order to impart flame retardancy to a nonaqueous electrolytic solution, Patent Document 1 discloses a method of using an electrolytic solution containing a phosphate ester having at least one fluorine atom in a molecular chain. Patent Document 2 discloses a method of using an electrolytic solution containing a phosphate ester such as trimethyl phosphate and a bisphosphonate ester.

JP 2007-258067 A JP 2012-248311 A

However, in the method of adding a flame retardant to the electrolytic solution as in Patent Document 1 or 2, the amount of the flame retardant added is large, which adversely affects charge / discharge cycle characteristics, output characteristics, etc., and charge / discharge of the lithium ion secondary battery. There was a problem that the characteristics deteriorated.
The present invention provides a lithium ion secondary battery that can reduce the risk of ignition of the electrolyte by suppressing an exothermic reaction when the lithium ion secondary battery becomes high temperature without deteriorating charge / discharge characteristics. An object of the present invention is to provide an additive, an electrode for a lithium ion secondary battery containing the additive, an electrolytic solution, and the like.

As a result of intensive studies to achieve the above object, the present inventors have reached the present invention. That is, the present invention provides an additive for a lithium ion secondary battery containing a compound (C) having a bond (a) having a structure represented by the following general formula (1) and a group (b) containing a group 15 element. (D); an electrode and electrolyte containing the additive (D); a lithium ion secondary battery having the electrode and / or electrolyte.

[In general formula (1), R is a hydrogen atom or a C1-C12 organic group. ]

By using the electrode and / or electrolytic solution containing the additive (D) for lithium ion secondary battery of the present invention, the lithium ion secondary battery can be obtained without deteriorating the charge / discharge characteristics of the lithium ion secondary battery. When the temperature is high, the exothermic reaction can be suppressed, and the risk of ignition of the electrolyte can be reduced.

<Additive for lithium ion secondary battery (D)>
When the additive (D) for a lithium ion secondary battery of the present invention is added to an electrode (preferably a positive electrode) or an electrolyte of a lithium ion secondary battery, the battery temperature becomes high due to an abnormality such as a short circuit. In addition, a passive film is formed on the surface of the active material of the electrode. The reaction between the active oxygen and the electrolytic solution is suppressed by the action of the coating, and an exothermic reaction can be suppressed.

The additive (D) for lithium ion secondary batteries of the present invention contains a compound (C) having a bond (a) having a structure represented by the general formula (1) and a group (b) containing a group 15 element. To do.

The number of bonds (a) and groups (b) in one molecule of compound (C) is not particularly limited. When a plurality of bonds (a) and / or groups (b) are present in one molecule, the plurality of bonds (a) and / or groups (b) may all be the same or different. The number of bonds (a) in one molecule of compound (C) is preferably 1-6, more preferably 1-5, and even more preferably 2 or 3. The number of groups (b) in one molecule of compound (C) is preferably 1 to 3.

Specific examples of the bond (a) in the compound (C) include a urethane bond (a1), a urea bond (a2), an allophanate bond (a3), and a biuret bond (a4).

The urethane bond (a1) is a bond represented by -OCONH-,
The urea bond (a2) is a bond represented by -NHCONH-,
The allophanate bond (a3) is a bond represented by the following formula (9):

The biuret bond (a4) is a bond represented by the following formula (10).

An example of the group 15 element in the group (b) is phosphorus (P).
As the group (b) containing a group 15 element contained in the compound (C), those represented by the following general formula (2) are preferably used.

[In General Formula (2), X ¹ and X ² are each independently a group represented by the following General Formula (3) or (4). ]

[In General Formula (3), R ¹ is a hydrogen atom or an organic group having 1 to 12 carbon atoms. ]

[In General Formula (4), M ⁺ is a monovalent metal ion. ]

Examples of the organic group having 1 to 12 carbon atoms in the general formula (3) include a hydrocarbon group having 1 to 12 carbon atoms or a hydrocarbon group having 1 to 12 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom. preferable.
Examples of the hydrocarbon group having 1 to 12 carbon atoms include linear or branched monovalent aliphatic hydrocarbon groups having 1 to 12 carbon atoms (for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, 1- Methylpropyl, isobutyl, t-butyl, n-pentyl, isopentyl, 1-methylbutyl, 2-methylbutyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1,2-dimethylpropyl, 1-ethylpropyl, n -Hexyl, isohexyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 1,1,2-trimethylpropyl, 1-ethyl-1-methyl Propyl, heptyl, octyl, isooctyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl), 5 to 1 carbon atoms Alicyclic hydrocarbon group (e.g., cyclopentyl, cyclohexyl, cyclohexylmethyl, cyclohexylethyl), the aromatic hydrocarbon group having 6 to 12 carbon atoms (e.g., phenyl, methylphenyl, benzyl) and the like.
Examples of the hydrocarbon group having 1 to 12 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom include 2,2,2-trifluoroethyl, 2,2,3,3-tetrafluoropropyl, 1H, 1H, 7H-dodecafluoroheptyl etc. are mentioned.
Among these, a linear or branched monovalent aliphatic hydrocarbon group having 1 to 12 carbon atoms and a hydrocarbon group having 1 to 12 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom are preferable. is there.

R ¹ is more preferably a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 2 carbon atoms, or a hydrocarbon group having 1 to 2 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, More preferably, they are a hydrogen atom, methyl or 2,2,2-trifluoroethyl.

Examples of the monovalent metal ion in the general formula (4) include lithium ion, sodium ion, potassium ion, rubidium ion, and cesium ion.
Among these, lithium ions or sodium ions are preferable from the viewpoint of output characteristics. More preferably, it is lithium ion.

Examples of the compound (C) include compounds represented by the following general formula (5).

In General Formula (5), Y is an n-valent hydrocarbon group having 2 to 42 carbon atoms (Y1) that may contain at least one atom selected from the group consisting of an oxygen atom, a sulfur atom, and a nitrogen atom. ,
Divalent residue obtained by removing two isocyanate groups from a urethane prepolymer having both terminal isocyanate groups, which is a reaction product of a diisocyanate (E) having 4 to 44 carbon atoms and a diol (F) having 2 to 20 carbon atoms (Y2),
Residue (Y3) obtained by removing n isocyanate groups from a modified diisocyanate (E) having 9 to 118 carbon atoms having an allophanate bond (a3)
Or a residue (Y4) obtained by removing n isocyanate groups from a diisocyanate (E) modified product having 11 to 131 carbon atoms having a biuret bond (a4),
n is an integer of 1 to 5, A is a urethane bond or urea bond, Z is an oxygen atom and a phosphorus atom, a group having 1 to 85 carbon atoms containing a group represented by the above general formula (2), or carbon It is a C1-C20 hydrocarbon group, and at least one is a C1-C85 group containing group represented by General formula (2).
In the general formula (5), when A is a urethane bond, the carbon atom constituting the urethane bond is bonded to the group represented by Z, and the nitrogen atom constituting the urethane bond is bonded to the group represented by Y. ing.

The hydrocarbon group (Y1) is an n-valent hydrocarbon group having 2 to 42 carbon atoms which may contain at least one atom selected from the group consisting of an oxygen atom, a sulfur atom and a nitrogen atom, preferably A divalent hydrocarbon group having 6 to 13 carbon atoms or a trivalent hydrocarbon having 9 to 30 carbon atoms, which may contain at least one atom selected from the group consisting of oxygen atom, sulfur atom and nitrogen atom More preferably a divalent hydrocarbon group having 6 to 13 carbon atoms. Specific examples include divalent aliphatic hydrocarbon groups (for example, ethylene, tetramethylene, hexamethylene, octamethylene, decamethylene, 1-methyltetramethylene, 2-methyltetramethylene), divalent alicyclic hydrocarbons. Groups such as 1,5,5-trimethyl-cyclohexane-1,3-diyl, methylenedicyclohexyl-4,4′-diyl, cyclohexane-1,4-diyl, 1,4-dimethylene-cyclohexane (1,4- A residue obtained by removing two hydroxyl groups from cyclohexanedimethanol) and a divalent aromatic hydrocarbon group (for example, toluene-2,4-diyl, toluene-2,6-diyl, methylenediphenyl-4,4 ′ -Diyl, xylylene, tetramethylxylylene, phenylene, 1,5-naphthylene), a trivalent hydrocarbon group having 9 to 42 carbon atoms. For example, a residue obtained by removing three isocyanate groups from a trimer of ethylene diisocyanate, a residue obtained by removing three isocyanate groups from a trimer of hexamethylene diisocyanate, and a three isocyanate from a trimer of isophorone diisocyanate From the viewpoint of the oxidative stability of the compound, preferred are a divalent aliphatic hydrocarbon group and a divalent alicyclic hydrocarbon group. Among these, a divalent aliphatic hydrocarbon group having 6 to 13 carbon atoms is preferable, and hexamethylene is more preferable.

Residue (Y2) is composed of two isocyanate groups from a urethane prepolymer having isocyanate groups at both ends obtained by reaction of a diisocyanate (E) having 4 to 44 carbon atoms and a diol (F) having 2 to 20 carbon atoms. It is a residue excluding.
Examples of the diisocyanate (E) having 4 to 44 carbon atoms include diisocyanates in which two isocyanate groups are added to the divalent hydrocarbon group (Y1).
Diols having 2 to 20 carbon atoms (F) include divalent aliphatic diols (ethylene glycol, tetramethylene glycol, hexamethylene glycol, 1,3-propanediol, 1,5-pentanediol, 1,8-octane. Diol, 1,10-decanediol, propylene glycol, 1,3-butanediol, etc.), divalent alicyclic hydrocarbon group (1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4 -Cyclohexanedimethanol etc.) etc. are mentioned.
The number average molecular weight of the urethane prepolymer having isocyanate groups at both ends is preferably 700 to 4800, and more preferably 1000 to 3000.

The residue (Y3) is a residue obtained by removing n isocyanate groups from a modified diisocyanate (E) having 9 to 118 carbon atoms having an allophanate bond (a3).
Examples of the modified C9-118 diisocyanate (E) having an allophanate bond (a3) include compounds represented by the following general formula (11).

[In General Formula (11), R ⁵ is a divalent group in the hydrocarbon group (Y1), and a plurality of R ⁵ may be the same or different. R ⁶ is a hydrocarbon group having 1 to 40 carbon atoms (preferably 1 to 20 carbon atoms). ]

R ⁶ is a linear or branched monovalent aliphatic hydrocarbon group having 1 to 40 carbon atoms (preferably 1 to 20 carbon atoms) (for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, 1-methylpropyl, isobutyl, t-butyl, n-pentyl, isopentyl, 1-methylbutyl, 2-methylbutyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1,2-dimethylpropyl, 1-ethylpropyl N-hexyl, isohexyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 1,1,2-trimethylpropyl, 1-ethyl-1 -Methylpropyl, heptyl, octyl, isooctyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl, tridecyl , Tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl), monovalent alicyclic hydrocarbon groups having 5 to 20 carbon atoms (for example, cyclopentyl, cyclohexyl, cyclohexylmethyl, cyclohexylethyl), etc. It is done.

In the general formula (11), R ⁵ is preferably each independently a divalent aliphatic hydrocarbon group having 6 to 13 carbon atoms, more preferably hexamethylene. R ⁶ is preferably a linear or branched monovalent aliphatic hydrocarbon group having 1 to 40 carbon atoms (more preferably 1 to 20 carbon atoms).

Residue (Y4) is a residue obtained by removing n isocyanate groups from a modified diisocyanate (E) having 11 to 131 carbon atoms having biuret bond (a4).
As a C11-131 diisocyanate (E) modified substance which has a biuret bond (a4), the compound represented, for example by the following general formula (12) is mentioned.

[In General Formula (12), R ⁷ is a divalent group in the hydrocarbon group (Y1), and a plurality of R ⁷ may be the same or different. ]
R ⁷ is preferably each independently a divalent aliphatic hydrocarbon group having 6 to 13 carbon atoms, more preferably hexamethylene.

In the said General formula (5), n is an integer of 1-5, Preferably it is an integer of 1-3.
A is a urethane bond or a urea bond. Two or more As may be urethane bonds, all urea bonds, or both urethane bonds and urea bonds, but all are preferably urethane bonds.

In the general formula (5), Z includes an oxygen atom and a phosphorus atom, and is a group having 1 to 85 carbon atoms or a hydrocarbon group having 1 to 20 carbon atoms containing the group represented by the general formula (2). is there. Examples of the group having 1 to 85 carbon atoms containing an oxygen atom and a phosphorus atom and containing the group represented by the general formula (2) include groups represented by the following general formula (6) or (7). .

[In General Formula (6), R ² is an (m ₁ +1) -valent hydrocarbon group having 1 to 12 carbon atoms, and m ₁ is an integer of ₁ to 3. X ¹ and ^{X 2} are the same respectively as ^{X 1} and ^{X 2} in the general formula (2). ]

[In General Formula (7), R ³ is an (m ₂ +1) -valent hydrocarbon group having 1 to 12 carbon atoms, and m ₂ is an integer of 1 to 3. X ¹ and ^{X 2} are the same respectively as ^{X 1} and ^{X 2} in the general formula (2). ]

The ^{R 2, R 3} in the general formula (7) in the general formula (6), a divalent aliphatic hydrocarbon group (e.g. having 1 to 12 carbon atoms, methylene, ethylene, tetramethylene, hexamethylene, octamethylene Methylene, decamethylene, 1-methyltetramethylene, 2-methyltetramethylene), divalent alicyclic hydrocarbon groups (for example, 1,5,5-trimethyl-cyclohexane-1,3-diyl, methylenedicyclohexyl-4, 4′-diyl, cyclohexane-1,4-diyl, 1,4-dimethylene-cyclohexane (residue obtained by removing two hydroxyl groups from 1,4-cyclohexanedimethanol), divalent aromatic hydrocarbon group ( For example, toluene-2,4-diyl, toluene-2,6-diyl, xylylene, tetramethylxylylene, phenylene, 1,5-naphthylene), trivalent fat Aliphatic hydrocarbon group (for example, methine, ethylidene, propyridine, butyridine), trivalent alicyclic hydrocarbon group (for example, cyclohexane-1,3,5-triyl, 1,4-dimethylene-cyclohexane-1- Yl), trivalent aromatic hydrocarbon group (for example, toluene-2,4,6-triyl), tetravalent aliphatic hydrocarbon group, tetravalent alicyclic hydrocarbon group, tetravalent aromatic carbon group A hydrogen group etc. are mentioned.
Among these, a divalent or trivalent aliphatic hydrocarbon group is preferable. More preferably, it is a C1-C2 bivalent or trivalent aliphatic hydrocarbon group.

When n in the general formula (5) is 2 or more, as Z, if at least one is a group having 1 to 85 carbon atoms containing a group represented by the general formula (2), the other Z is carbon The hydrocarbon group of number 1-20 may be sufficient.
Examples of the hydrocarbon group having 1 to 20 carbon atoms include linear or branched monovalent saturated aliphatic hydrocarbon groups having 1 to 20 carbon atoms (for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, 1 -Methylpropyl, isobutyl, t-butyl, n-pentyl, isopentyl, 1-methylbutyl, 2-methylbutyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, isohexyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 1,1,2-trimethylpropyl, 1-ethyl-1- Methylpropyl, heptyl, octyl, isooctyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl, tridecyl Tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl), monovalent saturated alicyclic hydrocarbon group having 5 to 20 carbon atoms (for example, cyclopentyl, cyclohexyl, cyclohexylmethyl, cyclohexylethyl), carbon number 2 -20 linear or branched monovalent unsaturated hydrocarbon groups (for example, hydroxyl groups are removed from unsaturated alcohols such as vinyl alcohol, citronellol, linalool, 3-methyl-2-buten-1-ol, geraniol, and retinol) Residue) and the like. Preferred is an unsaturated hydrocarbon group represented by the following general formula (8). A linear or branched monovalent saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms is also preferred.

[In the general formula (8), ^{R 4} is a divalent hydrocarbon group having 1 to 12 carbon atoms. T ^{1 to} T ³ are each independently one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an aromatic group having 6 to 12 carbon atoms, and each form a ring. Also good. ]

The divalent hydrocarbon group having 1 to 12 carbon atoms as R ⁴ in the general formula (8) is a divalent aliphatic hydrocarbon group having 1 to 12 carbon atoms (for example, methylene, ethylene, tetramethylene, hexa Methylene, octamethylene, decamethylene, 1-methyltetramethylene, 2-methyltetramethylene, 3-methylpentamethylene), divalent alicyclic hydrocarbon group (for example, 1,5,5-trimethyl-cyclohexane-1, 3-diyl, methylenedicyclohexyl-4,4′-diyl, cyclohexane-1,4-diyl, 1,4-dimethylene-cyclohexane (residue obtained by removing two hydroxyl groups from 1,4-cyclohexanedimethanol)), Divalent aromatic hydrocarbon groups (for example, toluene-2,4-diyl, toluene-2,6-diyl, xylylene, tetramethylxylyl Emissions, phenylene, 1,5-naphthylene), and the like.

Examples of the alkyl group having 1 to 4 carbon atoms as T ^{1 to} T ³ in the general formula (8) include methyl, ethyl, n-propyl, isopropyl, n-butyl, 1-methylpropyl, 2-methylpropyl and t- Examples include butyl. Of these, methyl is preferable. Examples of the aromatic group having 6 to 12 carbon atoms include phenyl and methylphenyl.

Compound (C) can be obtained, for example, by the following method.
(1) A compound (I1) having two or more isocyanate groups is synthesized by reacting an active hydrogen compound (J) having a group represented by the general formula (2).
(2) In the above (1), in place of (I1), at least one bond (a) selected from the group consisting of an allophanate bond (a3) and a biuret bond (a4) and having two or more isocyanate groups The compound (I2) is synthesized.
(3) In the above (1), in place of (I1), a urethane having a both-end isocyanate group which is a reaction product of a diisocyanate (E) having 4 to 44 carbon atoms and a diol (F) having 2 to 20 carbon atoms Synthesize using prepolymer (I3).

The reactions (1) to (3) are preferably performed in the presence of a urethanization catalyst from the viewpoint of shortening the reaction time.
The reaction is carried out without using a solvent or in a solvent. Examples of the reaction solvent include N-methylpyrrolidone, N, N-dimethylformamide, dioxolane and the like. The reaction time is usually 1 to 24 hours, but preferably 5 to 8 hours.
The order of preparation is not particularly limited, and the active hydrogen compound may be charged first, or the compound having an isocyanate group may be charged first.

Examples of the compound (I1) include ethylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane 4,4′-diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, and ethylene diisocyanate trimer. , Hexamethylene diisocyanate trimer, isophorone diisocyanate trimer, and the like.
Examples of the compound (I2) include compounds having a structure represented by the above general formula (11) as a compound having an allophanate bond (a3) and having two or more isocyanate groups. Examples of the compound having a biuret bond (a4) and having two or more isocyanate groups include compounds having a structure represented by the general formula (12). As such compound (I2), Duranate (registered trademark) A201H (allophanate-modified hexamethylene diisocyanate) [manufactured by Asahi Kasei Chemicals Co., Ltd.], Duranate 24A-100 (biuret-modified hexamethylene diisocyanate) [manufactured by Asahi Kasei Chemicals Co., Ltd.] ] Etc. are mentioned. Examples of the compound (I3) include a urethane prepolymer obtained by reacting hexamethylene diisocyanate and 1,4-cyclohexanedimethanol.

Examples of the diisocyanate compound (E) having 4 to 44 carbon atoms include ethylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane 4,4′-diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate. Can be mentioned.

Examples of the diol compound (F) having 2 to 20 carbon atoms include 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, 1 , 4-cyclohexanediethanol and the like.

The active hydrogen compound (J) is, for example, a compound having active hydrogen capable of reacting with an isocyanate group and having a group represented by the general formula (2). Examples of the active hydrogen include active hydrogen such as a hydroxyl group and an amino group.
Examples of the active hydrogen compound (J) having a group represented by the general formula (2) include dimethyl (hydroxymethyl) phosphonic acid, diethyl (hydroxymethyl) phosphonic acid, dimethyl (2-hydroxyethyl) phosphonic acid, diethyl (2 -Hydroxyethyl) phosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid (etidronic acid), 1-hydroxyethane-1,1-diphosphonic acid dilithium (etidronic acid dilithium), diethyl (aminomethyl) phosphonic acid , Dimethyl (2-aminoethyl) phosphonic acid, bis (2,2,2-trifluoroethyl) (2-hydroxyethyl) phosphoric acid, and the like.

Although the additive (D) for lithium ion secondary batteries may contain components other than a compound (C), it is preferable not to contain components other than (C). Examples of components other than the compound (C) include vinylene carbonate, fluoroethylene carbonate, chloroethylene carbonate, ethylene sulfite, propylene sulfite, and α-bromo-γ-butyrolactone.
The content of the compound (C) in the additive (D) for lithium ion secondary batteries is preferably 10 to 100% by weight, more preferably 50 to 100% by weight, based on the weight of (D). is there. Only one type of compound (C) may be used, or two or more types may be used in combination. The content of the compound (C) is the total amount when two or more compounds (C) are used.

<Electrode>
An electrode containing the additive for lithium ion secondary battery (D) is also one aspect of the present invention.
The electrode of the present invention may be a positive electrode or a negative electrode, but is preferably a positive electrode.
The electrode of the present invention usually contains an active material (K) and a binder (L) together with an additive (D) for a lithium ion secondary battery.
Examples of the active material (K) include a negative electrode active material (K1) and a positive electrode active material (K2).
As the negative electrode active material (K1), graphite, amorphous carbon, a polymer compound fired body (for example, a product obtained by firing and carbonizing a phenol resin, a furan resin, etc.), cokes (for example, pitch coke, needle coke, and petroleum coke), Examples thereof include carbon fibers, conductive polymers (for example, polyacetylene and polypyrrole), tin, silicon, and metal alloys (for example, lithium-tin alloy, lithium-silicon alloy, lithium-aluminum alloy, and lithium-aluminum-manganese alloy). . Only one type of negative electrode active material (K1) may be used, or two or more types may be used in combination.
As the positive electrode active material (K2), a composite oxide of lithium and a transition metal (for example, LiCoO ₂ , LiNiO ₂ , LiMnO ₂ and LiMn ₂ O ₄ ), a transition metal oxide (for example, MnO ₂ and V ₂ O ₅ ), transition Examples thereof include metal sulfides (eg, MoS ₂ and TiS ₂ ), and conductive polymers (eg, polyaniline, polyvinylidene fluoride, polypyrrole, polythiophene, polyacetylene, poly-p-phenylene, and polycarbazole). Only one type of positive electrode active material (K2) may be used, or two or more types may be used in combination.

Examples of the binder (L) include high molecular compounds such as starch, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, and polypropylene. These may be used alone or in combination of two or more.

The electrode of the present invention can further contain a conductive additive (M).
As the conductive auxiliary agent (M), graphite (for example, natural graphite and artificial graphite) (except when graphite is used as the active material (K)), carbon blacks (for example, carbon black, acetylene black, ketjen black, channel black, Furnace black, lamp black and thermal black), metal powder (for example, aluminum powder and nickel powder), and conductive metal oxide (for example, zinc oxide and titanium oxide).

Lithium ion secondary battery additive (D) based on the total weight of lithium ion secondary battery additive (D), active material (K) and binder (L) in the electrode of the present invention, active material ( The preferred contents of K), the binder (L), and the conductive auxiliary agent (M) are as follows.
The content of the additive (D) for the lithium ion secondary battery is preferably 0.05 to 5% by weight, more preferably 0.1 to 2% by weight, from the viewpoint of the heat generation suppressing effect and the charge / discharge cycle characteristics. It is.
The content of the active material (K) is preferably 70 to 98% by weight, more preferably 90 to 98% by weight, from the viewpoint of battery capacity.
The content of the binder (L) is preferably 0.5 to 29% by weight and more preferably 1 to 10% by weight from the viewpoint of battery capacity.
The content of the conductive auxiliary agent (M) is preferably 0 to 29% by weight, more preferably 1 to 10% by weight, from the viewpoint of battery output.

The electrode of the present invention is prepared by adding, for example, an additive (D) for a lithium ion secondary battery, an active material (K), a binder (L), and, if necessary, a conductive additive (M) in water or a solvent in an amount of 20 to 60. What was dispersed and slurried at a concentration of weight% was applied to a current collector with a coating device such as a bar coater, dried to remove the solvent, and if necessary, pressed with a press machine.

As the solvent, lactam compounds, ketone compounds, amide compounds, amine compounds, cyclic ether compounds and the like can be used.
Examples thereof include 1-methyl-2-pyrrolidone, methyl ethyl ketone, dimethylformamide, dimethylacetamide, N, N-dimethylaminopropylamine, and tetrahydrofuran.
Examples of the current collector include copper, aluminum, titanium, stainless steel, nickel, baked carbon, conductive polymer, and conductive glass.

<Electrolyte>
The electrolytic solution of the present invention contains an additive (D) for a lithium ion secondary battery, an electrolyte (G), and a nonaqueous solvent (H), and is preferably useful as an electrolytic solution for a lithium ion secondary battery.

The electrolyte (G), normal is can be used such as those used in the electrolytic solution, for _{example, LiPF 6, LiBF 4, LiSbF} 6, LiAsF 6 , and lithium salts of inorganic acids LiClO _4, etc., LiN (CF ₃ Examples include lithium salts of organic acids such as SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ and LiC (CF ₃ SO ₂ ) ₃ . Among these, LiPF ₆ is preferable from the viewpoint of battery output and charge / discharge cycle characteristics.

As the non-aqueous solvent (H), those used in ordinary electrolytes can be used, for example, lactone compounds, cyclic or chain carbonates, chain carboxylates, cyclic or chain ethers, phosphoric acid Esters, nitrile compounds, amide compounds, sulfones, sulfolanes, and the like and mixtures thereof can be used.

Of the non-aqueous solvents (H), cyclic or chain carbonates are preferred from the viewpoint of battery output and charge / discharge cycle characteristics.
Specific examples of the cyclic carbonate include propylene carbonate, ethylene carbonate, butylene carbonate, and the like.
Specific examples of the chain carbonate include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl-n-propyl carbonate, ethyl-n-propyl carbonate, and di-n-propyl carbonate.

Lithium ion secondary battery additive (D), electrolyte (G) based on the total weight of additive (D), electrolyte (G) and non-aqueous solvent (H) in the electrolyte solution of the present invention And preferable content of each of the non-aqueous solvent (H) is as follows.

The content of the additive (D) for a lithium ion secondary battery is preferably 0.01 to 10% by weight, more preferably 0. 0% from the viewpoints of heat generation suppression effect, charge / discharge cycle characteristics, battery capacity and high temperature storage characteristics. 05 to 1% by weight.
The content of the electrolyte (G) in the electrolytic solution is preferably 0.1 to 30% by weight, and more preferably 0.5 to 20% by weight from the viewpoint of battery output and charge / discharge cycle characteristics.
The content of the non-aqueous solvent (H) is preferably 60 to 99% by weight and more preferably 85 to 95% by weight from the viewpoint of battery output and charge / discharge cycle characteristics.

The electrolytic solution of the present invention may further contain additives such as an overcharge inhibitor, a dehydrating agent and a capacity stabilizer. The content of each component of the following additives is based on the total weight of the additive (D) for the lithium ion secondary battery, the electrolyte (G), and the nonaqueous solvent (H).
Examples of the overcharge inhibitor include biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, aromatic compounds such as cyclohexylbenzene, t-butylbenzene, and t-amylbenzene. The content of the overcharge inhibitor is usually 0 to 5% by weight, preferably 0.5 to 3% by weight.

Examples of the dehydrating agent include zeolite, silica gel and calcium oxide. The content of the dehydrating agent is usually 0 to 5% by weight, preferably 0.5 to 3% by weight.

Examples of the capacity stabilizer include fluoroethylene carbonate, succinic anhydride, 1-methyl-2-piperidone, heptane, and fluorobenzene. The content of the capacity stabilizer is usually 0 to 5% by weight, preferably 0.5 to 3% by weight.

The method for preparing the electrolytic solution of the present invention is not particularly limited. For example, the additive for lithium ion secondary battery (D), the electrolyte (G), and other additives that are optionally added to the nonaqueous solvent (H). It can be prepared by dissolving.

A lithium ion secondary battery can be obtained using an electrode and / or an electrolyte containing the additive for lithium ion secondary batteries. A lithium ion secondary battery having at least one of the electrode and the electrolytic solution of the present invention is also one aspect of the present invention.

<Lithium ion secondary battery>
The lithium ion secondary battery of the present invention uses, for example, the electrode of the present invention as a positive electrode or a negative electrode when an electrolyte is injected into a battery can containing a positive electrode, a negative electrode, and a separator to seal the battery can, The electrolytic solution of the present invention is used as the electrolytic solution, or a combination thereof is used.

As a separator in a lithium ion secondary battery, a microporous film made of polyethylene or polypropylene film, a multilayer film of porous polyethylene film and polypropylene, a nonwoven fabric made of polyester fiber, aramid fiber, glass fiber, etc., and silica on the surface thereof , Alumina and titania and other ceramic fine particles are attached.

As the battery can in the lithium ion secondary battery, metal materials such as stainless steel, iron, aluminum, and nickel-plated steel can be used, but plastic materials can also be used depending on the battery application. Further, the battery can can be formed into a cylindrical shape, a coin shape, a square shape, or any other shape depending on the application.

EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to these. Hereinafter, unless otherwise specified, “%” represents “% by weight” and “parts” represents “parts by weight”.

<Example 1>
Additive (D-1)
In a flask equipped with a stirrer, a thermometer and a condenser, 18.0 parts of dimethyl (2-hydroxyethyl) phosphonic acid (I-1) [manufactured by Wako Pure Chemical Industries, Ltd.], hexamethylene diisocyanate [Wako Pure Chemical Industries, Ltd.] 9.8 parts of hexamethylene diisocyanate manufactured by Kogyo Co., Ltd., 100 parts of N, N-dimethylformamide [manufactured by Tokyo Chemical Industry Co., Ltd.] and 0.07 part of dibutyltin dilaurate [manufactured by Tokyo Chemical Industry Co., Ltd.] The preparation was heated at 80 ° C. for 5 hours. The resulting reaction solution was allowed to cool to room temperature, suspended in methanol and purified by filtration to obtain 12.5 parts of a compound (C-1) represented by the following formula (13) ( Yield 45%). Compound (C-1) is used as additive (D-1).

<Production Example 1>
A flask equipped with a dilithium etidronate stirrer and a thermometer was charged with 5.0 parts of a 60% etidronic acid aqueous solution [manufactured by Wako Pure Chemical Industries, Ltd.], and lithium hydroxide monohydrate while cooling in an ice bath. The product [manufactured by Wako Pure Chemical Industries, Ltd.] was neutralized with an aqueous solution containing 1.32 parts. The obtained aqueous solution was heated to evaporate water, and then dried under reduced pressure (1.3 kPa) to obtain 3.0 parts of dilithium etidronate (I-2) (yield 95%).

<Example 2>
Additive (D-2)
The same procedure as in Example 1 was carried out except that 25.4 parts of etidronate dilithium (I-2) was used instead of 18.0 parts of dimethyl (2-hydroxyethyl) phosphonic acid (I-1). 14.8 parts of compound (C-2) represented by the formula (14) was obtained (42% yield). Let compound (C-2) be additive (D-2).

<Example 3>
Additive (D-3)
The same procedure as in Example 1 was carried out except that 21.2 parts of hexamethylene diisocyanate trimer [Asahi Kasei Co., Ltd.] was used instead of 9.8 parts of hexamethylene diisocyanate. 13.7 parts of compound (C-3) were obtained (yield 35%). Compound (C-3) is referred to as additive (D-3).

<Example 4>
Additive (D-4)
In a flask equipped with a stirrer, thermometer and condenser, 16.9 parts etidronate dilithium (I-2), 21.2 parts hexamethylene diisocyanate trimer, 100 parts N, N-dimethylformamide and dibutyltin dilaurate 0.07 part was charged and heated at 80 ° C. for 5 hours. Subsequently, 5.5 parts of n-octanol [manufactured by Wako Pure Chemical Industries, Ltd.] was charged and heated at 80 ° C. for 5 hours. The resulting reaction solution was allowed to cool to room temperature, suspended in methanol and purified by filtration to obtain 13.8 parts of a compound (C-4) represented by the following formula (16) ( Yield 32%). Compound (C-4) is referred to as additive (D-4).

<Example 5>
Additive (D-5)
In a flask equipped with a stirrer, a thermometer and a condenser tube, 8.4 parts of 1,4-cyclohexanedimethanol [Tokyo Chemical Industry Co., Ltd.], 14.7 parts of hexamethylene diisocyanate, N, N-dimethylformamide 100 And 0.07 part of dibutyltin dilaurate were charged and heated at 80 ° C. for 5 hours. Subsequently, 9.0 parts of dimethyl (2-hydroxyethyl) phosphonic acid (I-1) was charged and heated at 80 ° C. for 5 hours. The resulting reaction solution was allowed to cool to room temperature, suspended in methanol and purified by filtration to obtain 12.2 parts of a compound (C-5) represented by the following formula (17) ( Yield 38%). Compound (C-5) is referred to as additive (D-5). In the following formula (17), n is 2.

<Example 6>
Additive (D-6)
Instead of 18.0 parts of dimethyl (2-hydroxyethyl) phosphonic acid (I-1), 17.9 parts of dimethyl (2-aminoethyl) phosphonic acid [manufactured by Tokyo Chemical Industry Co., Ltd.] (I-3) Example 11 was carried out in the same manner as in Example 1 to obtain 11.1 parts of the compound (C-6) represented by the following formula (18) (yield 40%). Compound (C-6) is used as additive (D-6).

<Example 7>
Additive (D-7)
The same procedure as in Example 2 was carried out except that 28.7 parts of duranate A201H (allophanate-modified hexamethylene diisocyanate) [Asahi Kasei Co., Ltd.] was used instead of 9.8 parts of hexamethylene diisocyanate. 17.9 parts of a compound (C-7) represented by the formula (33% yield) was obtained. Compound (C-7) is referred to as additive (D-7).

［式（１９）中、Ｒ^８は炭素数６〜４０である長鎖アルキル基である。］

[In Formula (19), R ⁸ is a long-chain alkyl group having 6 to 40 carbon atoms. ]

<Example 8>
Additive (D-8)
The same procedure as in Example 1 was carried out except that 18.6 parts of duranate 24A-100 (biuret-modified hexamethylene diisocyanate) [Asahi Kasei Co., Ltd.] was used instead of 9.8 parts of hexamethylene diisocyanate. 20) (12.8 parts of compound (C-8)) was obtained (yield 35%). Compound (C-8) is used as additive (D-8).

<Example 9>
Additive (D-9)
In a flask equipped with a stirrer, a thermometer and a condenser tube, 9.0 parts of dimethyl (2-hydroxyethyl) phosphonic acid (I-1), 9.8 parts of hexamethylene diisocyanate, 100 parts of N, N-dimethylformamide and dilaurin 0.07 part of dibutyltin acid was charged and heated at 80 ° C. for 5 hours. Subsequently, 9.1 parts of citronellol [manufactured by Wako Pure Chemical Industries, Ltd.] were charged and heated at 80 ° C. for 5 hours. The resulting reaction liquid was allowed to cool to room temperature, suspended in methanol and purified by filtration to obtain 12.3 parts of a compound (C-9) represented by the following formula (21) ( Yield 44%). Compound (C-9) is referred to as additive (D-9).

<Production Example 2>
Bis (2,2,2-trifluoroethyl) (2-hydroxyethyl) phosphoric acid (I-4)
A flask equipped with a stirrer, a thermometer, a dropping funnel and a condenser tube was charged with 20.0 parts of phosphoryl chloride [manufactured by Wako Pure Chemical Industries, Ltd.] and 100 parts of methyl ethyl ketone, and 26.1 parts of trifluoroethanol and 31. of pyridine. 0 part was added from the dropping funnel and stirred at room temperature for 2 hours. Further, 24.3 parts of ethylene glycol was added and heated at 80 ° C. for 5 hours. The resulting reaction solution was allowed to cool to room temperature, 200 parts of water and 200 parts of ethyl acetate were added, and the aqueous layer was separated. Ethyl acetate was removed under reduced pressure (1.3 kPa), and bis (2,2,2-trifluoroethyl) (2-hydroxyethyl) phosphoric acid (I-4) 24.8 represented by the following formula (22): Part was obtained (62% yield).

<Example 10>
Additive (D-10)
Instead of 18.0 parts of dimethyl (2-hydroxyethyl) phosphonic acid (I-1), 35.7 bis (2,2,2-trifluoroethyl) (2-hydroxyethyl) phosphoric acid (I-4) 35.7 Except having used a part, it carried out similarly to Example 1 and obtained 20.5 parts of compounds (C-10) shown by following formula (23) (yield 45%). Compound (C-10) is referred to as additive (D-10).

<Comparative Example 1>
Comparative additive (D'-1)
Trimethyl phosphate was used as a comparative additive (D′-1).

<Comparative example 2>
Comparative additive (D'-2)
Tri (2,2,2-trifluoroethyl) phosphate was used as a comparative additive (D′-2).

The additives (D-1) to (D-10) of the present invention are summarized in Table 1.

Evaluation of Lithium Ion Secondary Battery and Electrode <Examples 11 to 20 and Comparative Examples 3 to 5>
A positive electrode for a lithium ion secondary battery containing the additive (D) or the comparative additive (D ′) in the number of parts shown in Table 2 is prepared by the following method, and the positive electrode is used by the following method. A lithium ion secondary battery was produced.
Table 2 shows the results of evaluating the high voltage charge / discharge cycle characteristics, output characteristics, calorific value, and exothermic peak temperature of the produced lithium ion secondary battery by the following method.

[Preparation of positive electrode for lithium ion secondary battery]
9 parts by weight of LiCoO ₂ powder, 5.0 parts by Ketjen Black [manufactured by Sigma Aldrich], 5.0 parts by polyvinylidene fluoride [manufactured by Sigma Aldrich] and the number of parts shown in Table 2 (D) or (D ′ ) Was thoroughly mixed in a mortar, 70.0 parts of 1-methyl-2-pyrrolidone was added, and further mixed well in a mortar to obtain a slurry. The obtained slurry was applied to one side of an aluminum electrolytic foil having a thickness of 20 μm using a wire bar in the air, dried at 80 ° C. for 1 hour, and further under reduced pressure (1.3 kPa) at 80 ° C. It was dried for 2 hours and punched out to 15.95 mmφ to produce a positive electrode for a lithium ion secondary battery.

[Preparation of negative electrode for lithium ion secondary battery]
A slurry was obtained by sufficiently mixing 92.5 parts of graphite powder having an average particle size of about 8 to 12 μm, 7.5 parts of polyvinylidene fluoride, and 200 parts of 1-methyl-2-pyrrolidone in a mortar. The obtained slurry was applied to one side of a copper foil having a thickness of 20 μm using a wire bar in the atmosphere, dried at 80 ° C. for 1 hour, and further reduced pressure (1.3 kPa) at 80 ° C. for 2 hours. It was dried for a time, punched to 16.15 mmφ, and made a negative electrode for a lithium ion secondary battery with a thickness of 30 μm using a press.

[Production of lithium ion secondary battery]
The positive electrode and the negative electrode prepared as described above were arranged at both ends in the 2032 type coin cell so that the coated surfaces face each other, and a separator (polypropylene nonwoven fabric) was inserted between the electrodes to prepare a secondary battery cell. Lithium ions were injected and sealed in a cell in which an electrolytic solution was prepared by dissolving LiPF ₆ in a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) (volume ratio 1: 1) at a ratio of 12% by weight. A secondary battery was produced.

<Evaluation of high voltage charge / discharge cycle characteristics>
The lithium ion secondary battery was charged to a voltage of 4.5 V with a current of 0.1 C using a charge / discharge measuring device “Battery Analyzer 1470 type” [manufactured by Toyo Technica Co., Ltd.], and after 0 minutes of rest, 0 The battery voltage was discharged to 3.5 V with a current of 1 C, and this charge / discharge was repeated. At this time, the battery capacity at the first charge and the battery capacity at the 50th cycle charge were measured, and the charge / discharge cycle characteristics were calculated from the following formula. It shows that charging / discharging cycling characteristics are so favorable that a numerical value is large.
High voltage charge / discharge cycle characteristics (%) = (battery capacity at the 50th cycle charge / battery capacity at the first charge) × 100

<Evaluation of secondary battery output characteristics>
The lithium ion secondary battery was charged to a voltage of 4.5 V with a current of 0.1 C using a charge / discharge measuring device “Battery Analyzer 1470 type” [manufactured by Toyo Technica Co., Ltd.], and after 0 minutes of rest, 0 The voltage was discharged to 3.0 V with a current of 1 C, and the discharge capacity (hereinafter referred to as 0.1 C discharge capacity) was measured. Next, the battery is charged to a voltage of 4.5 V with a current of 0.1 C, and after a pause of 10 minutes, the voltage is discharged to 3.0 V with a current of 1 C, and the capacity (hereinafter referred to as 1 C discharge capacity) is measured. The capacity retention rate during 1C discharge was calculated. The larger the value, the better the output characteristics.
Capacity maintenance rate during 1 C discharge (%) = (1 C discharge capacity / 0.1 C discharge capacity) × 100

<Evaluation of calorific value and exothermic peak temperature>
The lithium ion secondary battery was charged to a voltage of 4.3 V with a current of 0.1 C using a charge / discharge measuring device “Battery Analyzer 1470 type” [manufactured by Toyo Technica Co., Ltd.], and after a pause of 10 minutes, 0 The battery voltage was discharged to 3.0 V with a current of 0.1 C, and this charge / discharge was repeated three times, and then charged to a voltage of 4.3 V with a current of 0.1 C. This battery was decomposed under an argon atmosphere, the positive electrode was taken out, washed with diethyl carbonate, and dried under reduced pressure (1.3 kPa) for 2 hours. Subsequently, about 3 mg of the positive electrode is placed in an LVC pan (pressure pan) under an argon atmosphere, 12 wt% of LiPF ₆ in a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) (volume ratio 1: 1). About 2 mg of the electrolytic solution dissolved at a rate of% was put to prepare a measurement sample. The sample was heated from 25 ° C. to 320 ° C. at a rate of 5 ° C./minute using a differential scanning calorimeter (DSC) [manufactured by Perkin Elmer Co., Ltd.], and the calorific value and exothermic peak temperature were measured.

Evaluation of Lithium Ion Secondary Battery and Electrolyte <Examples 21 to 30 and Comparative Examples 6 to 7>
A lithium ion secondary battery using the electrolytic solution for a lithium ion secondary battery containing the additive (D) or the comparative additive (D ′) in the number of parts shown in Table 2 was produced by the following method. About the produced lithium ion secondary battery, the high voltage charging / discharging cycle characteristic and output characteristic were evaluated by said method similarly to the case of an electrode, and the result was shown in Table 2. Table 2 shows the results of evaluating the calorific value and the exothermic peak temperature by the following method.

[Preparation of electrolyte]
87.5 parts of a mixed solvent of ethylene carbonate and diethyl carbonate (volume ratio 1: 1) is blended with the additive (D) or comparative additive (D ′) in the number of parts shown in Table 2, and 12 wt. % and the LiPF ₆ dissolved at, to prepare an electrolytic solution.

[Production of positive electrode]
After thoroughly mixing 90.0 parts of LiCoO ₂ powder, 5.0 parts of Ketjen black and 5.0 parts of polyvinylidene fluoride in a mortar, 70.0 parts of 1-methyl-2-pyrrolidone was added, and further in a mortar. Mix well to obtain a slurry. The obtained slurry was applied to one side of an aluminum electrolytic foil having a thickness of 20 μm using a wire bar in the air, dried at 80 ° C. for 1 hour, and further under reduced pressure (1.3 kPa) at 80 ° C. It was dried for 2 hours, punched out to 15.95 mmφ, and a positive electrode for a lithium ion secondary battery having a film thickness of 30 μm was produced.

[Production of negative electrode]
A slurry was obtained by sufficiently mixing 92.5 parts of graphite powder having an average particle diameter of about 8 to 12 μm, 7.5 parts of polyvinylidene fluoride and 200 parts of 1-methyl-2-pyrrolidone in a mortar. The obtained slurry was applied to one side of a copper foil having a thickness of 20 μm using a wire bar in the atmosphere, dried at 80 ° C. for 1 hour, and further reduced pressure (1.3 kPa) at 80 ° C. for 2 hours. It was dried for a time, punched to 16.15 mmφ, and made a negative electrode for a lithium ion secondary battery with a thickness of 30 μm using a press.

[Production of lithium ion secondary battery]
The positive electrode and the negative electrode were arranged at both ends in the 2032 type coin cell so that the coated surfaces face each other, and a separator (polypropylene nonwoven fabric) was inserted between the electrodes to produce a secondary battery cell.
The electrolyte solution was poured into the produced secondary battery cell and then sealed to produce a lithium ion secondary battery.

<Evaluation of calorific value and exothermic peak temperature>
The prepared lithium ion secondary battery was charged to a voltage of 4.3 V with a current of 0.1 C using a charge / discharge measuring device “Battery Analyzer 1470 type” [manufactured by Toyo Technica Co., Ltd.], and after 10 minutes of rest The battery voltage was discharged to 3.0 V with a current of 0.1 C, and this charge / discharge was repeated three times, and then charged to a voltage of 4.3 V with a current of 0.1 C. This battery was decomposed under an argon atmosphere, the positive electrode was taken out, washed with diethyl carbonate, and dried under reduced pressure (1.3 kPa) for 2 hours. Subsequently, about 3 mg of the positive electrode and about 2 mg of an electrolytic solution containing the additive (D) or the comparative additive (D ′) in the blending number shown in Table 2 in an LVC pan (pressure-resistant pan) under an argon atmosphere. A sample for measurement was prepared. The sample was heated from 25 ° C. to 320 ° C. at a rate of 5 ° C./minute using a differential scanning calorimeter (DSC) [manufactured by Perkin Elmer Co., Ltd.], and the calorific value and exothermic peak temperature were measured.

The lithium ion secondary battery produced using the battery additive of the present invention has a high temperature when the lithium ion secondary battery itself is heated without deteriorating charge / discharge characteristics such as charge / discharge cycle characteristics and output characteristics. It was found that the exothermic reaction can be suppressed. The reason why the exothermic reaction is suppressed is considered that a passive film is formed at the interface due to the reaction of the additive at a high temperature, and the reaction between the active oxygen and the electrolytic solution is suppressed.

Since the electrode and electrolyte using the additive (D) for lithium ion secondary battery of the present invention can improve the safety of the battery by suppressing exothermic reaction, the lithium ion secondary battery of the present invention The additive (D) is useful as an electrode for a lithium ion secondary battery and an additive for an electrolytic solution, and is particularly suitable for an electric vehicle and the like.

Claims (12)

The additive (D) for lithium ion secondary batteries containing the compound (C) which has the group (b) containing the coupling | bonding (a) which has the structure represented by following General formula (1), and a 15 group element.

[In general formula (1), R is a hydrogen atom or a C1-C12 organic group. ] The additive (D) for lithium ion secondary batteries according to claim 1, wherein the group (b) containing a group 15 element is a group represented by the following general formula (2).

[In General Formula (2), X ¹ and X ² are each independently a group represented by the following General Formula (3) or (4). ]

[In General Formula (3), R ¹ is a hydrogen atom or an organic group having 1 to 12 carbon atoms. ]

[In General Formula (4), M ⁺ is a monovalent metal ion. ] The lithium ion according to claim 1 or 2, wherein the bond (a) is at least one bond selected from the group consisting of a urethane bond (a1), a urea bond (a2), an allophanate bond (a3), and a biuret bond (a4). Secondary battery additive (D). The additive (D) for lithium ion secondary batteries according to any one of claims 1 to 3, wherein the compound (C) is a compound represented by the following general formula (5).

[In General Formula (5), Y is an n-valent hydrocarbon group having 2 to 42 carbon atoms (Y1) which may contain at least one atom selected from the group consisting of an oxygen atom, a sulfur atom and a nitrogen atom. ),
Divalent residue obtained by removing two isocyanate groups from a urethane prepolymer having both terminal isocyanate groups, which is a reaction product of a diisocyanate (E) having 4 to 44 carbon atoms and a diol (F) having 2 to 20 carbon atoms (Y2),
Residue (Y3) obtained by removing n isocyanate groups from a modified diisocyanate (E) having 9 to 118 carbon atoms having an allophanate bond (a3)
Or a residue (Y4) obtained by removing n isocyanate groups from a diisocyanate (E) modified product having 11 to 131 carbon atoms having a biuret bond (a4),
n is an integer of 1 to 5, A is a urethane bond or urea bond, Z is an oxygen atom and a phosphorus atom, a group having 1 to 85 carbon atoms containing a group represented by the above general formula (2), or carbon It is a C1-C20 hydrocarbon group, and at least one is a C1-C85 group containing group represented by General formula (2). ] The additive for lithium ion secondary batteries (D) according to claim 4, wherein Z is a group represented by the following general formula (6).

[In General Formula (6), R ² is an (m ₁ +1) -valent hydrocarbon group having 1 to 12 carbon atoms, and m ₁ is an integer of ₁ to 3. X ¹ and ^{X 2} are the same respectively as ^{X 1} and ^{X 2} in the general formula (2). ] The additive for lithium ion secondary batteries (D) according to claim 4, wherein Z is a group represented by the following general formula (7).

[In General Formula (7), R ³ is an (m ₂ +1) -valent hydrocarbon group having 1 to 12 carbon atoms, and m ₂ is an integer of 1 to 3. X ¹ and ^{X 2} are the same respectively as ^{X 1} and ^{X 2} in the general formula (2). ] The organic group having 1 to 12 carbon atoms in the general formula (3) is a hydrocarbon group having 1 to 12 carbon atoms or a hydrocarbon group having 1 to 12 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom. The additive (D) for lithium ion secondary batteries according to any one of claims 1 to 6. The additive for lithium ion secondary batteries (D) according to any one of claims 1 to 7, wherein the monovalent metal ion in the general formula (4) is a lithium ion or a sodium ion. N in the general formula (5) is 2 or more, at least one of Z is a group represented by the following general formula (6) or (7), and the remaining Z is the following general formula (8) The additive for lithium ion secondary batteries (D) according to any one of claims 4, 7, and 8, which is a group represented.

[In General Formula (6), R ² is an (m ₁ +1) -valent hydrocarbon group having 1 to 12 carbon atoms, and m ₁ is an integer of ₁ to 3. X ¹ and ^{X 2} are the same respectively as ^{X 1} and ^{X 2} in the general formula (2). ]

[In General Formula (7), R ³ is an (m ₂ +1) -valent hydrocarbon group having 1 to 12 carbon atoms, and m ₂ is an integer of 1 to 3. X ¹ and ^{X 2} are the same respectively as ^{X 1} and ^{X 2} in the general formula (2). ]

[In the general formula (8), ^{R 4} is a divalent hydrocarbon group having 1 to 12 carbon atoms. T ^{1 to} T ³ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aromatic group having 6 to 12 carbon atoms, and may form a ring with each other. ] The electrode containing the additive (D) for lithium ion secondary batteries of any one of Claims 1-9. The electrolyte solution containing the additive (D) for lithium ion secondary batteries of any one of Claims 1-9, electrolyte (G), and a nonaqueous solvent (H). The lithium ion secondary battery which has at least any one among the electrode of Claim 10, and the electrolyte solution of Claim 11.