JP2015225689A - Additive agent for battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode or an electrolyte for a lithium ion battery that is excellent in charge/discharge cycles.SOLUTION: An additive agent (B) for a battery contains a compound (A) having an urethane bond (a) and a fluorinated hydrocarbon group (b) in which at least one hydrogen atom of a hydrocarbon group is substituted with a fluorine atom and having no polymerizable unsaturated bonds. The fluorinated hydrocarbon group (b) is preferably a 2-20C fluorinated alkyl group or a 2-20C fluorinated alkylene group, and a fluorine atom bonded to a carbon atom of the fluorinated hydrocarbon group (b) is preferably 20 mol% or more with respect to the total mole number of a hydrogen atom and a fluorine atom in the (b).

Description

  The present invention relates to a battery additive, an electrode and an electrolytic solution containing the battery additive, and a battery having at least one of the electrode and the electrolytic solution.

  Non-aqueous electrolyte secondary batteries such as lithium-ion batteries are characterized by high voltage and high energy density, so they are widely used in the field of portable information devices and are used for mobile terminals such as mobile phones and notebook computers. The position as a standard battery has been established. While its uses are expanding, application to hybrid vehicles and electric vehicles in addition to conventional uses is also being studied, and some have already been put into practical use. In order to further spread these, there is a demand for higher performance and higher capacity of secondary batteries, and various techniques have been applied.

As one method for improving the capacity of a lithium ion battery, a method using silicon, tin, or the like in place of the conventionally used graphite-based active material has been studied. Since these elements form an alloy with lithium, they have a very high theoretical capacity compared to graphite (graphite: 372 mAh / g, silicon: 4200 mAh / g, tin: 994 mAh / g). However, these alloy-forming active materials have a problem that the cycle characteristics are greatly inferior to those of the graphite-based active materials because the volume change accompanying charging / discharging is large.

  For example, Patent Document 1 discloses a technique using fluoroethylene carbonate to solve the problem of deterioration of cycle characteristics of a silicon-based active material. Patent Document 2 discloses a technique using triallyl isocyanate. Patent Document 3 discloses a technique of adding a spiro ammonium salt to an electrolytic solution.

JP 2011-49114 A JP 2014-73733 A Special table 2013-542562 gazette

However, even with these techniques, satisfactory cycle characteristics cannot be expressed yet.
An object of this invention is to provide the electrode or electrolyte solution for lithium ion batteries excellent in the charge / discharge cycle.

  As a result of intensive studies to achieve the above object, the present inventors have reached the present invention. That is, the present invention relates to a compound having a urethane bond (a) and a fluorinated hydrocarbon group (b) in which at least one hydrogen atom of the hydrocarbon group is substituted with a fluorine atom, and having no polymerizable unsaturated bond ( Battery additive (B) containing A); Electrode containing the battery additive (B); Electrolytic solution containing the battery additive (B); At least one of the electrode and the electrolytic solution It is a battery which has.

  By using the electrode or electrolytic solution containing the battery additive (B) of the present invention, the cycle characteristics and output characteristics of the battery can be improved.

  The battery additive (B) of the present invention has a urethane bond (a) and a fluorinated hydrocarbon group (b) in which at least one hydrogen atom of the hydrocarbon group is substituted with a fluorine atom, and a polymerizable unsaturated bond The compound (A) which does not have is contained.

The compound (A) used for the battery additive (B) of the present invention does not have a polymerizable unsaturated bond. When a polymerizable unsaturated bond is contained, it becomes easy to form a SEI (Solid Electrolyte Interface, solid electrolyte interface) on the electrode. However, since the film thickness of the SEI increases, there is a problem that the electrode resistance increases, so that the output characteristics are increased. From the viewpoint, it is preferable not to have a polymerizable unsaturated bond.
The polymerizable unsaturated bond in the present invention means a carbon-carbon double bond and a carbon-carbon triple bond. Specific examples of the functional group having a polymerizable unsaturated bond include allyl group, methylallyl group, dimethylallyl group, acryloyl group, methacryloyl group and styryl group.

Specific examples of the fluorinated hydrocarbon group (b) in which at least one hydrogen atom of the hydrocarbon group of the compound (A) used in the present invention is substituted with a fluorine atom include a fluorinated alkyl group having 2 to 20 carbon atoms. Or a C2-C20 fluorinated alkylene group is mention | raise | lifted.
Specific examples of the fluorinated alkyl group having 2 to 20 carbon atoms include 2-fluoroethyl group, 2,2-difluoroethyl group, 2,2,2-trifluoroethyl group, 2,2,3,3-tetrafluoro. Propyl group, 2,2,3,3,4,4,5,5-octafluoropentyl, 1H, 1H, 7H-dodecafluoroheptyl group, 1H, 1H, 2H, 2H-heptadecafluorodecyl and perfluorocyclohexyl Examples thereof include a methyl group. Of these, 2,2,2-trifluoroethyl group is preferably used from the viewpoint of battery characteristics.
Specific examples of the fluorinated alkylene group having 2 to 20 carbon atoms include 2,2,3,3-tetrafluorobutylene group, 2,2,3,3,4,4,5,5-octafluorohexamethylene group and Examples include perfluorodecamethylene group. Of these, 2,2,3,3-tetrafluorobutylene groups are preferably used from the viewpoint of battery characteristics.

The fluorine atom bonded to the carbon skeleton of the fluorinated hydrocarbon group (b) is preferably 20 mol% or more, more preferably 40% or more, based on the total amount of hydrogen atoms and fluorine atoms in (b). .

  As the compound (A) used in the present invention, a compound represented by the following general formula (1) or (2) is preferably used.

［式（１）中、Ｒ^１は炭素数２〜２０のフッ素化アルキル基である。Ｒ^２はポリイソシアネート化合物からイソシアネート基を除いた残基であり（ｍ＋ｎ）価の基である。Ｒ^３は炭素数１〜２０の有機基であり、重合性不飽和結合を有さない。ｍは１〜４の整数であり、ｎは０〜３の整数である。]

[In formula (1), ^{R 1} is a fluorinated alkyl group having 2 to 20 carbon atoms. R ² is a residue obtained by removing an isocyanate group from a polyisocyanate compound, and is a (m + n) -valent group. R ³ is an organic group having 1 to 20 carbon atoms and does not have a polymerizable unsaturated bond. m is an integer of 1 to 4, and n is an integer of 0 to 3. ]

［式（２）中、Ｒ^４およびＲ^８は炭素数２〜２０のフッ素化アルキル基または炭素数１〜２０の有機基である。Ｒ^５およびＲ^７はジイソシアネート化合物からイソシアネート基を除いた残基である。Ｒ^６は炭素数２〜２０のフッ素化アルキレン基または炭素数１〜２０の２価の有機基である。ｋは１〜１０の整数である。分子中に複数のＲ^５および複数のＲ^６が含まれる場合、同一でも異なっていてもよい。分子中には炭素数２〜２０のフッ素化アルキル基または炭素数２〜２０のフッ素化アルキレン基を少なくとも１つ有する。］

[In the formula (2), ^{R 4} and ^{R 8} is a fluorinated alkyl group or an organic group having 1 to 20 carbon atoms having 2 to 20 carbon atoms. R ⁵ and R ⁷ are residues obtained by removing an isocyanate group from a diisocyanate compound. R ⁶ is a fluorinated alkylene group having 2 to 20 carbon atoms or a divalent organic group having 1 to 20 carbon atoms. k is an integer of 1-10. When a plurality of R ⁵ and a plurality of R ⁶ are contained in the molecule, they may be the same or different. The molecule has at least one fluorinated alkyl group having 2 to 20 carbon atoms or fluorinated alkylene group having 2 to 20 carbon atoms. ]

R ¹ in Formula (1) is a fluorinated alkyl group having 2 to 20 carbon atoms. Specific examples of the fluorinated alkyl group having 2 to 20 carbon atoms include 2-fluoroethyl group, 2,2-difluoroethyl group, 2,2,2-trifluoroethyl group, 2,2,3,3-tetrafluoro. Propyl group, 2,2,3,3,4,4,5,5-octafluoropentyl, 1H, 1H, 7H-dodecafluoroheptyl group, 1H, 1H, 2H, 2H-heptadecafluorodecyl and perfluorocyclohexyl Examples thereof include a methyl group. Of these, 2,2,2-trifluoroethyl group is preferably used from the viewpoint of battery characteristics.

R ² in the formula (1) is a (m + n) -valent residue obtained by removing an isocyanate group from a polyisocyanate compound. m is an integer of 1 to 4, and n is an integer of 0 to 3. Specific examples of the polyisocyanate compound include monoisocyanate compounds having 2 to 20 carbon atoms (for example, ethyl isocyanate, butyl isocyanate, octyl isocyanate, dodecyl isocyanate, etc.), diisocyanate compounds having 4 to 20 carbon atoms (for example, hexamethylene diisocyanate, isophorone diisocyanate, And dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, tolylene diisocyanate, and the like, and triisocyanate compounds having 6 to 30 carbon atoms (for example, bimuret modification of hexamethylene diisocyanate, isocyanurate modification of hexamethylene diisocyanate).

R ³ in the formula (1) is a monovalent organic group having 1 to 20 carbon atoms and does not have a polymerizable unsaturated bond. Specific examples of the organic group having 1 to 20 carbon atoms include aliphatic hydrocarbon groups having 1 to 20 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, octyl group, dodecyl group, and octadecyl group), carboxyl Or a C1-C20 aliphatic hydrocarbon group substituted with an alkali metal salt group of a sulfo group (for example, a residue obtained by removing a hydroxyl group from lithium glycolate, a residue obtained by removing a hydroxyl group from lithium lactate, and isethionic acid A residue obtained by removing one hydroxyl group from a polyalkylene glycol chain (for example, a residue obtained by removing one hydroxyl group from ethylene glycol, a residue obtained by removing one hydroxyl group from diethylene glycol, tetra A residue obtained by removing one hydroxyl group from ethylene glycol and a monoalkyl etherified product thereof or Such as cetyl product), and the like. Of these, an aliphatic hydrocarbon group having 1 to 20 carbon atoms is preferably used.

R ⁴ and R ⁸ in the formula (2) are a fluorinated alkyl group having 2 to 20 carbon atoms or an organic group having 1 to 20 carbon atoms. Specific examples thereof are the same as those preferred in the above formula (1).
R ⁵ and R ⁷ are residues obtained by removing isocyanate from a diisocyanate compound. Specific examples of the diisocyanate compound include hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and tolylene diisocyanate.

R ⁶ in the formula (2) is a fluorinated alkylene group having 2 to 20 carbon atoms. Specific examples of the fluorinated alkylene group having 2 to 20 carbon atoms include 2,2,3,3-tetrafluorobutylene group, 2,2,3,3,4,4,5,5-octa. Examples thereof include a fluorohexamethylene group and a perfluorodecamethylene group.

Examples of the method for producing the compound (A) include a method of reacting the corresponding polyisocyanate compound (c1) with the corresponding alcohol compound (c2). The reaction can be carried out by a known urethanization technique.
(C2) is divided into alcohol (c21) having a hydrocarbon group in which at least one hydrogen atom is substituted with a fluorine atom and other alcohol (c22), and (c21) is used in the reaction as an essential component.

  Specific examples of the polyisocyanate compound (c1) include monoisocyanate compounds having 2 to 20 carbon atoms (for example, ethyl isocyanate, butyl isocyanate, octyl isocyanate, dodecyl isocyanate, etc.), diisocyanate compounds having 4 to 20 carbon atoms (for example, hexamethylene diisocyanate, Isophorone diisocyanate, dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, tolylene diisocyanate, etc.), triisocyanate compounds having 6 to 30 carbon atoms (for example, biuret-modified products of hexamethylene diisocyanate, isocyanurate-modified products of hexamethylene diisocyanate) can give.

Specific examples of (c21) include 2-fluoroethanol, 2,2-difluoroethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoropropanol, 2,2,3,3, 4,4,5,5-octafluoropentanol, 1H, 1H, 7H-dodecafluoroheptanol, 1H, 1H, 2H, 2H-heptadecafluoro-1-decanol and perfluorocyclohexylmethanol, 2,2,3 , 3-tetrafluoro-1,4-butanediol, 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol and perfluoro-1,10-decanediol can give.
Specific examples of (c22) include aliphatic alcohols having 1 to 20 carbon atoms (for example, methanol, ethanol, propanol, butanol, octanol, dodecanol and octadecanol), and aromatic alcohol groups having 6 to 20 carbon atoms (for example, Benzyl alcohol and cinnamyl alcohol), aliphatic alcohols having 1 to 20 carbon atoms (eg, lithium glycolate, lithium lactate and lithium isethionate) and polyalkylenes substituted with carboxyl group or alkali metal group of sulfo group Examples thereof include glycols (for example, ethylene glycol, diethylene glycol, tetraethylene glycol and monoalkyl etherified products or acetylated products thereof).

The compound represented by the general formula (1) can be synthesized by reacting a monoalcohol compound among (c1) and (c2).
The compound represented by the general formula (2) is obtained by reacting the diisocyanate compound in (c1) with the dialcohol compound in (c2) and reacting the remaining isocyanate group with the monoalcohol in (c2). Can do.

The battery additive (B) of the present invention contains the compound (A) as an essential component and can contain other compounds. Examples of the compound that (B) may contain include vinylene carbonate, fluoroethylene carbonate, chloroethylene carbonate, ethylene sulfite, propylene sulfite, propane sultone, and α-bromo-γ-butyrolactone. Of these, fluoroethylene carbonate is preferably used from the viewpoint of battery characteristics.
The content of (A) in (B) is preferably 1 to 100% by weight based on the weight of (B), more preferably 10 to 100% by weight, and particularly preferably 30 to 100% by weight.

  In the present invention, the battery includes an electrochemical device such as a lithium ion battery, a lithium ion capacitor, an electric double layer capacitor, a lead storage battery, a nickel-cadmium battery, and a nickel metal hydride battery.

The electrode of the present invention contains a battery additive (B), an active material (D), and a binder (E). You may contain the conductive support agent (F) as needed.
The electrode of the present invention is obtained by dispersing (B), (D), (E) and, if necessary, (F) in a solvent to obtain a slurry, coating the slurry on a current collector, and drying the organic solvent You can get it.

A negative electrode for a lithium ion battery can be obtained by using the negative electrode active material (D1) as the active material (D), and a negative electrode for a lithium ion capacitor can be obtained by doping lithium into (D1). Examples of the positive electrode (D) include a positive electrode active material (D2) for a lithium ion battery and a positive electrode active material (D3) for a lithium ion capacitor.
Examples of (D1) include graphite, amorphous carbon, polymer compound fired bodies (for example, those obtained by firing and carbonizing phenol resin and furan resin), cokes (for example, pitch coke, needle coke, and petroleum coke), carbon fibers, Examples thereof include 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).
The lithium ion battery of the present invention preferably contains silicon as (D1) from the viewpoint of battery capacity. The silicon content in (D1) is preferably 0.5 to 100% by weight, more preferably 5 to 50% by weight from the viewpoint of battery capacity and other battery characteristics.
(D2) includes lithium and transition metal composite oxides (eg LiCoO ₂ , LiNiO ₂ , LiMnO ₂ and LiMn ₂ O ₄ ), transition metal oxides (eg MnO ₂ and V ₂ O ₅ ), transition metal sulfides (For example, MoS ₂ and TiS ₂ ), and conductive polymers (for example, polyaniline, polyvinylidene fluoride, polypyrrole, polythiophene, polyacetylene, poly-p-phenylene, and polycarbazole).
Examples of (D3) include activated carbon, carbon fiber, and conductive polymer (for example, polyacetylene and polypyrrole).

  Examples of the binder (E) include high molecular compounds such as starch, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, and polypropylene.

  The conductive auxiliary agent (F) contained in the electrode of the present invention as an optional component includes carbon blacks (for example, carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black and thermal black) and metal powder (for example Aluminum powder and nickel powder), conductive metal oxides (for example, zinc oxide and titanium oxide), and the like.

  Examples of the solvent used in preparing the electrode of the present invention include water, N-methylpyrrolidone, acetone and toluene.

Preferred contents of each of (D), (E), (B), and (F) based on the total weight of the active material (D), binder (E), and battery additive (B) in the electrode of the present invention. The amounts are as follows.

The content of the active material (D) 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 (E) is preferably 0.5 to 29% by weight, more preferably 1 to 10% by weight from the viewpoint of battery capacity.
The content of (B) is preferably 0.01 to 10% by weight, more preferably 0.05 to 1% by weight, from the viewpoints of charge / discharge cycle characteristics, battery capacity, and high-temperature storage characteristics.
The content of the conductive auxiliary agent (F) is preferably 0 to 29% by weight, more preferably 1 to 10% by weight, from the viewpoint of battery output.

The electrolytic solution of the present invention contains a battery additive (B), an electrolyte (G), and a non-aqueous solvent (H).
The electrolytic solution of the present invention can be obtained by dissolving (B) and (G) in (H).

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.

  Battery additive (B), electrolyte (G) and non-aqueous solvent (H) based on the total weight of battery additive (B), electrolyte (G) and non-aqueous solvent (H) in the electrolytic solution of the present invention Each preferable content is as follows.

The content of (B) is preferably 0.01 to 10% by weight, more preferably 0.05 to 1% by weight, from the viewpoints of charge / discharge cycle characteristics, battery capacity, and high-temperature storage characteristics.
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 battery additive (B), 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 usage-amount of an overcharge inhibiting agent is 0-5 weight% normally, Preferably it is 0.5-3 weight%.

  Examples of the dehydrating agent include zeolite, silica gel and calcium oxide. The usage-amount of a dehydrating agent is 0-5 weight% normally based on the total weight of electrolyte solution, Preferably it is 0.5-3 weight%.

  Examples of the capacity stabilizer include fluoroethylene carbonate, succinic anhydride, 1-methyl-2-piperidone, heptane, and fluorobenzene. The usage-amount of a capacity | capacitance stabilizer is 0-5 weight% normally based on the total weight of electrolyte solution, Preferably it is 0.5-3 weight%.

  The lithium ion battery of the present invention uses the electrode of the present invention as the positive electrode or the negative electrode when the electrolytic solution is injected into the battery can containing the positive electrode, the negative electrode, and the separator to seal the battery can. It can be obtained by using the electrolytic solution of the invention or a combination thereof.

  As a separator in a lithium ion 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, alumina on the surface thereof And those having ceramic fine particles such as titania attached thereto.

  As the battery can in the lithium ion 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>
Synthesis of Compound (A-1) In a flask equipped with a stirrer, a thermometer and a condenser tube, 6.1 parts of 2,2,2-trifluoroethanol, 5.8 parts of butyl isocyanate, 100 parts of toluene and Tris (2 -Ethylhexanoic acid) 0.1 parts of bismuth was charged and heated at 80 ° C for 8 hours. Toluene was removed under reduced pressure (1.3 kPa) to obtain 11.0 parts of (A-1) represented by the following chemical formula (3). (A-1) was designated as battery additive (B-1).

<Example 2>
Synthesis of Compound (A-2) This was performed in the same manner as in Example 1 except that 4.9 parts of hexamethylene diisocyanate was used instead of 5.8 parts of butyl isocyanate, and represented by the following chemical formula (4) (A-2) 10.2 parts were obtained. (A-2) was designated as battery additive (B-2).

<Example 3>
Synthesis of Compound (A-3) This was carried out in the same manner as in Example 1 except that 9.7 parts of a biuret-modified product of hexamethylene diisocyanate was used instead of 5.8 parts of butyl isocyanate, and represented by the following chemical formula (5) ( A-3) 16.8 parts were obtained. (A-3) was designated as battery additive (B-3).

<Example 4>
Synthesis of Compound (A-4) The reaction was performed in the same manner as in Example 2 except that 3.9 parts of 2-fluoroethanol was used instead of 6.1 parts of 2,2,2-trifluoroethanol, and the following chemical formula (6) 8.1 parts of a compound (A-4) represented by (A-4) was designated as battery additive (B-4).

<Example 5>
Synthesis of Compound (A-5) Instead of 6.1 parts of 2,2,2-trifluoroethanol, 14.2 parts of 2,2,3,3,4,4,5,5-octafluoropentanol was used. 17.5 parts of the compound (A-5) represented by the following chemical formula (7) was obtained in the same manner as in Example 2 except that. (A-5) was designated as battery additive (B-5).

<Example 6>
Synthesis of Compound (A-6) Example except that 2.9 parts of 2,2,2-trifluoroethanol and 1.9 parts of methanol were used instead of 6.1 parts of 2,2,2-trifluoroethanol 9.3 parts of a compound (A-6) represented by the following chemical formula (8) was obtained. (A-6) was designated as battery additive (B-6).

<Example 7>
Synthesis of compound (A-7) Instead of 6.1 parts of 2,2,2-trifluoroethanol, 2.9 parts of 2,2,2-trifluoroethanol and 3.9 parts of lithium isethionate were used. It carried out like Example 2 and obtained 11.0 parts of compounds (A-7) shown by following Chemical formula (9). (A-7) was designated as battery additive (B-7).

<Example 8>
Synthesis of Compound (A-8) In a flask equipped with a stirrer, a thermometer, and a condenser tube, 3.9 parts of 2,2,3,3-tetrafluoro-1,4-butanediol, hexamethylene diisocyanate 4.9 Parts, toluene 100 parts and tris (2-ethylhexanoic acid) bismuth 0.1 parts were charged and heated at 80 ° C. for 8 hours. Thereafter, 3.0 parts of 2,2,2-trifluoroethanol was added and further heated at 80 ° C. for 4 hours. Toluene was removed under reduced pressure (1.3 kPa) to obtain 9.3 parts of (A-8) represented by the following chemical formula (10). (A-8) was designated as battery additive (B-8).

<Example 9>
A battery additive (B-9) was prepared by mixing an equal amount of compound (A-1) and fluoroethylene carbonate.

<Comparative Example 1>
(A′-1) represented by the following chemical formula (11), which was carried out in the same manner as in Example 1 except that 2.0 parts of methanol was used instead of 6.1 parts of 2,2,2-trifluoroethanol. 6 parts were obtained. (A′-1) was used as a comparative additive (B′-1).

<Comparative Example 2>
Vinylene carbonate was defined as (A′-2). (A′-2) was used as a comparative additive (B′-2).

<Comparative Example 3>
Fluoroethylene carbonate was designated as (A′-3). (A′-3) was used as a comparative additive (B′-3).

  Table 1 summarizes the battery additive (B) of the example and the comparative additive (B ') of the comparative example.

<Examples 9 to 26, Comparative Examples 6 to 16>
Evaluation of Lithium Ion Battery, Electrode and Electrolyte A lithium ion battery electrode containing the above-mentioned battery additive (B) or comparative additive (B ′) in the number of parts shown in Table 2 was prepared by the following method. Using the electrode, a lithium ion battery was produced by the following method.
The results of evaluating charge / discharge cycle characteristics and low-temperature charge / discharge cycle characteristics by the following methods are shown in Table 2.

[Production of positive electrode for lithium ion battery]
9 parts by weight of LiCoO 2 powder, 5 parts by Ketjen Black [manufactured by Sigma-Aldrich Co., Ltd.], 5 parts by polyvinylidene fluoride [manufactured by Sigma-Aldrich Co., Ltd.] and the number of parts shown in Table 2 (B) or (B ′) After fully mixing with a mortar, 70.0 parts of 1-methyl-2-pyrrolidone [manufactured by Tokyo Chemical Industry Co., Ltd.] was added, and further mixed well with 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 positive electrodes for lithium ion batteries of Examples 9 to 26 and Comparative Examples 6 to 16.

[Preparation of negative electrode for lithium ion battery (1)]
90.0 parts of graphite powder having an average particle size of about 8 to 12 μm, 2.5 parts of silicon powder, 7.5 parts of polyvinylidene fluoride, 200 parts of 1-methyl-2-pyrrolidone [manufactured by Tokyo Chemical Industry Co., Ltd.] and table 2 parts (B) shown in 2 were thoroughly mixed in a mortar to obtain a slurry. The obtained slurry was applied to one side of a 20 μm-thick copper foil in the air using a wire bar, dried at 80 ° C. for 1 hour, and further under reduced pressure (1.3 kPa) at 80 ° C. for 2 hours. Drying was performed, punching out to 16.15 mmφ, and a thickness of 30 μm with a press machine to produce negative electrodes (1) for lithium ion batteries of Examples 9 to 26 and Comparative Examples 6 to 16.

[Preparation of negative electrode for lithium ion battery (2)]
A negative electrode (2) for a lithium ion battery was produced in the same manner as in the above (1) except that 90.0 parts of graphite powder and 2.5 parts of silicon powder were replaced with 92.5 parts of graphite powder.

[Preparation of negative electrode for lithium ion battery (3)]
A negative electrode (3) for a lithium ion battery was produced in the same manner as in the above (1) except that 90.0 parts of graphite powder and 2.5 parts of silicon powder were replaced with 92.5 parts of silicon powder.

[Preparation of electrolyte for lithium ion battery]
87.5 parts of a mixed solvent of ethylene carbonate and diethyl carbonate (volume ratio 1: 1) is blended with (B) or (B ′) in the number of parts shown in Table 2, and the electrolyte is 12% by weight. LiPF ₆ was dissolved, and electrolytic solutions of Examples 9 to 26 and Comparative Examples ₆ to 16 were prepared.

[Production of lithium-ion batteries]
The positive electrode and the negative electrode of Examples 7 to 20 and Comparative Examples 6 to 16 are arranged at both ends in the 2032 type coin cell so that the coated surfaces face each other, and a separator (polypropylene nonwoven fabric) is inserted between the electrodes, and lithium An ion battery cell was produced. The solution was poured 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 wt%. The charge / discharge cycle characteristics and the low-temperature charge / discharge cycle characteristics were evaluated by the following methods.

<Evaluation of charge / discharge cycle characteristics>
Using a charge / discharge measuring device “Battery Analyzer 1470” [manufactured by Toyo Technica Co., Ltd.] at room temperature, the battery was charged to a voltage of 4.3 V with a current of 0.1 C, and after a pause of 10 minutes, 0.1 C The battery voltage was discharged to 3.5 V with this current, and this charge / discharge was repeated. At this time, the battery capacity at the first charge and the battery capacity at the 30th 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.
Charging / discharging cycle characteristics (%) = (battery capacity at 30th charge / battery capacity at first charge) × 100

When comparing Examples 10 to 29 and Comparative Examples 4 and 7 to 12 using the negative electrode for lithium ion battery (1), Example 30 and Comparative Example 5 using the negative electrode for lithium ion battery (2) were compared. In this case, when Example 31 and Comparative Example 6 using the negative electrode for lithium ion battery (3) were compared, lithium ion provided with an electrode and / or electrolyte containing the battery additive (B) of the present invention. The battery was found to have excellent charge / discharge cycle characteristics. This is presumably because the compound (A) decomposed on the electrode surface to form effective SEI. Since Examples 20 and 29 using fluoroethylene carbonate are more effective, it is considered that more effective SEI is formed.

The electrode and electrolyte solution using the battery additive (B) of the present invention are effective for lithium ion batteries, and can be suitably used particularly for lithium ion batteries for electric vehicles. Moreover, it is applicable also to electrochemical devices (electric double layer capacitor, nickel metal hydride battery, nickel cadmium battery, air battery, alkaline battery, etc.) other than those disclosed in the present invention.

Claims (9)

  Contains a urethane bond (a) and a compound (A) having a fluorinated hydrocarbon group (b) in which at least one hydrogen atom of the hydrocarbon group is substituted with a fluorine atom, and having no polymerizable unsaturated bond Battery additive (B).   The battery additive (B) according to claim 1, wherein the fluorinated hydrocarbon group (b) is a fluorinated alkyl group having 2 to 20 carbon atoms or a fluorinated alkylene group having 2 to 20 carbon atoms.   The fluorine atom bonded to the carbon atom of the fluorinated hydrocarbon group (b) is 20 mol% or more based on the total number of moles of the hydrogen atom and the fluorine atom in (b). Battery additive. The battery additive (B) according to any one of claims 1 to 3, wherein the compound (A) is represented by the following general formula (1) or (2).

[In formula (1), ^{R 1} is a fluorinated alkyl group having 2 to 20 carbon atoms. R ² is a residue obtained by removing an isocyanate group from a polyisocyanate compound, and is a (m + n) -valent group. R ³ is an organic group having 1 to 20 carbon atoms and does not have a polymerizable unsaturated bond. m is an integer of 1 to 4, and n is an integer of 0 to 3. ]

[In the formula (2), ^{R 4} and ^{R 8} is a fluorinated alkyl group or an organic group having 1 to 20 carbon atoms having 2 to 20 carbon atoms. R ⁵ and R ⁷ are residues obtained by removing an isocyanate group from a diisocyanate compound. R ⁶ is a fluorinated alkylene group having 2 to 20 carbon atoms or a divalent organic group having 1 to 20 carbon atoms. k is an integer of 1-10. When a plurality of R ⁵ and a plurality of R ⁶ are contained in the molecule, they may be the same or different. The molecule has at least one fluorinated alkyl group having 2 to 20 carbon atoms or fluorinated alkylene group having 2 to 20 carbon atoms. ]   The electrode containing the additive (B) for batteries of any one of Claims 1-4.   The electrolyte solution containing the additive (B) for batteries of any one of Claims 1-4.   A battery having at least one of the electrode according to claim 5 and the electrolytic solution according to claim 6. The battery according to claim 7, wherein the battery is a lithium ion battery. The battery according to claim 8, comprising an electrode containing silicon as a negative electrode active material.