JP2001338682A - Nonaqueous electrolyte cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte cell preventing vaporization and decomposition of the electrolyte based on an organic solvent at wide range of temperature, with high safety at short circuit, excellent cell performance like cycle property, and excellent high temperature property. SOLUTION: The nonaqueous electrolyte cell comprises a positive pole, a negative pole capable of occluding and releasing lithium ion, and a nonaqueous electrolyte including lithium ion. The nonaqueous electrolyte is the liquid containing lithium salt and phosphagen derivative shown by the formula; (R1O)3P =N-SO2-R2 [where; R1 represents an alkyl group of 1-10 carbons which may be replaced by halogen atom, or represents the formula; CH3-(OCH2CH2)n-(n is an integer of 1-5) which may be replaced by halogen atom, and R2 represents alkyl group of 1-12 carbons which may be replaced by halogen atom, or phenyl group which may be replaced by halogen atom, alkoxyl group, or alkyl group of 1-4 carbons].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte battery having excellent battery performance without vaporization or decomposition of an organic solvent-based electrolyte over a wide temperature range.
More specifically, the present invention relates to a non-aqueous electrolyte battery that can improve cycle characteristics and high-temperature storage characteristics of the battery.

[0002]

2. Description of the Related Art In recent years, many portable electronic devices such as camera-type video tape recorders, mobile phones, and portable computers have appeared, and their size and weight have been reduced. Researches have been made to improve the energy density of batteries that are portable power sources for these electronic devices, particularly secondary batteries. Among secondary batteries, lithium-ion batteries are expected to have higher energy density than lead batteries and nickel-cadmium batteries, which are secondary batteries using conventional aqueous electrolytes. It is being advanced.

[0003] Non-aqueous electrolytes used in lithium batteries or lithium ion secondary batteries include carbonate-based electrolytes such as propylene carbonate and diethyl carbonate, and L-electrolytes as electrolytes.
A solution in which iPF ₆ is dissolved is widely used because it has relatively high conductivity and is stable in terms of potential. Among batteries using these nonaqueous electrolytes, lithium ion secondary batteries are known to have higher safety than batteries using metallic lithium.

[0004]

The above-mentioned carbonate-based non-aqueous solvent is generally said to be relatively electrochemically stable. However, in a non-aqueous electrolyte battery, the oxidizing power of the positive electrode and the negative electrode has been reduced. It is pointed out that these carbonate-based non-aqueous solvents may cause a reaction, albeit slightly, due to the very strong reducing power. When such a reaction occurs, a reaction product grows as a film on the electrode surface, which causes an increase in the impedance of the battery. As a result, there is a problem that the voltage drop becomes remarkable especially when discharging with a large current, and the cycle characteristics and the load characteristics deteriorate. In the above-mentioned lithium ion secondary battery, what has occurred remarkably at the end of charging when the positive electrode has a high potential or at the time of overcharging is that the solvent of the non-aqueous electrolyte is decomposed and the decomposition product (polymer, etc.) Adhered to the electrodes, resulting in an increase in the internal impedance of the battery after storage, resulting in a decrease in discharge characteristics and a further decrease in charge / discharge cycle characteristics.

[0005] By suppressing such decomposition of the non-aqueous electrolyte,
In order to improve storage characteristics and charge / discharge cycle characteristics, 2-methyltetrahydrofuran is obtained by substituting a part of hydrogen atoms of a cyclic ether such as tetrahydrofuran (THF) and 1,3-dioxolane (DOXL) with an alkyl group or the like. (2Me-THF), 4-methyl-1,3-dioxasolane (4Me-DOXL), etc. (JL
Goldman, RMMank, JH Young and VRKoch: J. Elect
rochem. Soc., 127, p1461 (1980)), a method of adding a sulfide compound such as methylphenyl sulfide, diphenyl sulfide, and chathrene (Japanese Patent Application Laid-Open No. 07-3207).
No. 79) has been proposed.

Further, Japanese Patent Application Laid-Open No. 06-13108 discloses
Indicates that the electrolyte of the non-aqueous electrolyte secondary battery has a viscosity of 25 ° C or higher.
Has a lithium salt on a phosphazene derivative of 300 cp or less.
Safe and excellent battery by using dissolved solution
It is described that performance is imparted. Disclosed here
The phosphazene derivatives used are (NPR^Two)_n(formula
Wherein R is a monovalent organic group, and n is a ring represented by 3 to 15)
Phosphazene derivative or R ^Three(P = N)_m-PR_Four(formula
Wherein m is 1 to 20, R is a monovalent organic group, O or C
Selected from The chain type phosphazene derivative represented by)
is there.

[0007] However, the above-mentioned conventional method of adding a certain chemical to an electrolytic solution is effective at room temperature in terms of suppressing decomposition of the electrolytic solution, but is still effective at high temperatures. Decomposition of the electrolytic solution occurs, which has the disadvantage of lowering the cycle characteristics.Furthermore, from the viewpoint of the flame retardancy of the electrolytic solution, although the flame retardancy is improved to some extent, the battery performance is reduced. There are drawbacks.
Also, with respect to the phosphazene derivative, the appearance of a compound that can impart more excellent battery performance has been desired.

Accordingly, the present invention suppresses the vaporization and decomposition of an organic solvent-based electrolyte in a wide temperature range, has high safety even in a short circuit, has excellent battery performance such as cycle characteristics, and has high-temperature storage characteristics. It is an object of the present invention to provide a non-aqueous electrolyte battery having excellent characteristics.

[0009]

Under such circumstances, the present inventors have conducted intensive studies. As a result, if a specific phosphazene derivative having a sulfonyl group is contained in the electrolyte of a nonaqueous electrolyte battery, a wide range of temperatures can be obtained. The present invention has been found to suppress vaporization and decomposition of the electrolytic solution and to provide excellent battery performance even in a high temperature range, particularly at high temperatures, and have completed the present invention.

That is, the present invention relates to a non-aqueous electrolyte battery comprising a positive electrode, a negative electrode capable of occluding or releasing lithium ions, and a non-aqueous electrolyte containing lithium ions. Formula (1); (R ¹ O) ₃ P = N—SO ₂ —R ² (1) In the formula, R ¹ is a straight-chain or a straight-chain having 1 to 10 carbon atoms which may be substituted with a halogen atom. A group represented by the following formula, which may be substituted with a branched alkyl group or a halogen atom; CH _3- (
OCH ₂ CH ₂ ) _n − (n represents an integer of 1 to 5), and R ² represents an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom, or a halogen atom, an alkoxy group or A phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms is shown. A non-aqueous electrolyte battery characterized by being a solution containing a phosphazene derivative represented by｝ and a lithium salt.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The electrolytic solution of the non-aqueous electrolyte battery of the present invention is a solution containing a phosphazene derivative represented by the above general formula (1) and a lithium salt. This is a solution in which a lithium salt is dissolved in a mixed solvent obtained by mixing a protic organic solvent.

In the present invention, the compound represented by the general formula (1) is used.
Wherein the phosphazene derivative is ¹Has 1 to 1 carbon atoms
0 linear or branched alkyl group, halogen atom
A linear or branched C1-C10 substituted with
An alkyl group, a group represented by the following formula; CH _Three-(OCH_TwoCH_Two)_n-
(N represents an integer of 1 to 5) or the group is halogen
It is substituted with an atom. The preferred number of n is 1-3
It is. A linear or branched alkyl having 1 to 10 carbon atoms
Examples of the kill group include a methyl group, an ethyl group, and n-propyl.
Propyl group, isopropyl group, n-butyl group, isobutyl
Group, sec-butyl group, n-hexyl group, isohexyl
Group, n-heptyl group, n-octyl group, isooctyl
Group, n-decyl group, isodecyl group and the like. Replace
The halogen atom is not particularly limited, but may be chlorine.
Atom or fluorine atom, particularly preferably fluorine
Is an atom.

In the formula of the phosphazene derivative represented by the general formula (1), R ² represents an alkyl group having 1 to 12 carbon atoms which may be substituted by a halogen atom, or a halogen atom, an alkoxy group or a carbon atom. A phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms, specifically, an alkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms substituted with a halogen atom, phenyl Group, a phenyl group substituted with a halogen atom, an alkoxyphenyl group, an alkoxyphenyl group substituted with a halogen atom,
It represents a phenyl group substituted with an alkyl group having 1 to 4 carbon atoms or a phenyl group substituted with an alkyl group having 1 to 4 carbon atoms substituted with a halogen atom.

Examples of the alkyl group having 1 to 12 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, an n-hexyl group and an isohexyl group. , N-heptyl group, n-octyl group, isooctyl group, n-decyl group,
And an isodecyl group. The halogen atom to be substituted is not particularly limited, but is preferably a chlorine atom or a fluorine atom, particularly preferably a fluorine atom.
Examples of the alkoxyphenyl group include methoxyphenyl, ethoxyphenyl, propoxyphenyl and the like.
As a preferable group of R ² , a part or all of a halogen atom such as a lower alkyl group having 1 to 4 carbon atoms such as an ethyl group and a methyl group, a trifluoromethyl group, a tetrafluoroethyl group and a hexafluoropropyl group are substituted. Alkyl group having 1 to 4 carbon atoms, a phenyl group, a phenyl group partially or wholly substituted with a halogen atom, a phenyl group substituted with a methyl group, a phenyl group substituted with a halogenated methyl group. Yes, and particularly preferred are a methyl group, a phenyl group, a monofluorophenyl group, and a difluorophenyl group.

The method for producing the phosphazene derivative represented by the general formula (1) includes, for example, a method according to the following reaction formulas (I) and (II).

PX ₅ + H ₂ N—SO ₂ —R ² → X ₃ P = N—SO ₂ —R ² (I) Formula (2) Formula (3) (wherein X represents a halogen atom, R ² has the same meaning as described above.)

X ₃ P = N—SO ₂ —R ² + R ¹ —OM → (R ¹ O) ₃ P = N—SO ₂ R ² (II) Formula (3) Formula (4) Formula (4) (1) (In the formula, M represents an alkali metal, and R ¹ and R ² are the same as described above.)

That is, in the above reaction formula (I), the halogenated phosphazene derivative represented by the general formula (3) is
It can be easily obtained by reacting a phosphorus halide with a sulfonamide (compound of the general formula (2)) in an organic solvent. In this case, the molar ratio of the sulfonamide (the compound of the general formula (2)) to the phosphorus halide is usually 0.1.
9 to 1.3, preferably 1.0 to 1.1, the reaction temperature is generally 0 to 50 ° C, preferably 20 to 40 ° C, and the reaction time is generally 0.5 to 4 hours, preferably Is 1
2 hours. The reaction solvent is not particularly limited as long as it is a solvent in which the reaction raw materials are soluble and is inert.For example, aromatic hydrocarbons such as toluene, xylene and benzene, acetonitrile and nitriles such as propionitrile And halogenated aromatic hydrocarbons such as chlorobenzene, haloalkanes such as methylene chloride and chloroform, and ethers such as tetrahydrofuran and dioxane. These can be used alone or in combination of two or more.

In the reaction formula (II), the target phosphazene derivative represented by the general formula (1) is a halogenated phosphazene derivative (compound of the general formula (3)) and an alcoholate (a general formula (4) Can be easily obtained by reacting the compound in an organic solvent. The molar ratio of the alcoholate (compound of the general formula (4)) to the halogenated phosphazene derivative (compound of the general formula (3)) is usually 2.0 to 4.5, preferably 2.7 to 3.3.
The reaction temperature is usually -20 to 40 ° C, preferably 0 to 20 ° C, and the reaction time is usually 2 to 12 hours, preferably 3 to 6 hours. The reaction solvent is not particularly limited as long as it is a solvent in which the halogenated phosphazene derivative and the alcoholate can be dissolved and is inert, and examples thereof include hydrocarbons, halogenated aromatic hydrocarbons, haloalkanes, dioxane, tetrahydrofuran, and dibutyl ether. Ethers, acetonitrile, propionitrile, and the like, and one or more of these can be used in combination. After completion of the reaction, the desired product is obtained by a conventional method such as drying and purification.

The electrolyte of the non-aqueous electrolyte battery of the present invention may contain impurities irreversibly mixed in the above-described method for producing a phosphazene derivative, as long as the battery performance is not impaired. , For example, phosphate esters,
It can be used in combination with a flame retardant compound such as a carbonate ester.

It is preferable to use a mixed solvent of the phosphazene derivative and an aprotic organic solvent for the electrolyte of the non-aqueous electrolyte battery of the present invention. The aprotic organic solvent is not particularly limited. For example, γ-butyrolactone, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolan, sulfolane, dimethyl carbonate, diethyl carbonate, methyl acetate, 1,2-dimethoxyethane Tetrahydrofuran, propylene carbonate, ethylene carbonate, butylene carbonate, formamide, dimethylformamide, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxymethane, sulfolane, 3-methyl-2-oxazolidinone, diethyl ether, And ether compounds such as 3,3-propanesultone and the like, and these may be used alone or in combination of two or more.

The compounding ratio of the phosphazene derivative is usually from 0.1 to 80 v / v as a volume fraction in the non-aqueous electrolyte.
% In the present invention, and this blending ratio in the present invention can be arbitrarily designed according to the purpose. That is, since the phosphazene derivative represented by the general formula (1) shows basicity, the phosphazene derivative and the negative electrode active material of the battery constituent material during the cycle of the battery at a high temperature, particularly in the process of repeating insertion and removal of lithium, are used. When used as a trapping agent such as a free acid generated from a decomposition product such as an electrolyte salt, a hydrofluoric acid or the like, or a stabilizer, the compounding ratio of the phosphazene derivative is usually 0.1% in a non-aqueous electrolyte. ２０20 v / v%, preferably 0.1 to 10 v / v
%, The cycle characteristics and high-temperature storage stability of the nonaqueous electrolyte battery can be improved.

When the non-aqueous electrolyte battery is provided with flame retardancy to suppress the rupture or ignition of the battery, it is usually 1 to 8
0 v / v%, preferably in the range of 10 to 40 v / v%. If it is less than 1 v / v%, it is not enough to suppress the rupture and ignition of the battery, while on the other hand it is 80 v / v%
If it exceeds, the viscosity of the solution increases, lithium ion conductivity suitable for large-current discharge is hardly obtained, and the battery performance tends to decrease when used at a low temperature below the freezing point, which is not preferable.

The lithium salt to be dissolved in the mixed solvent is not particularly limited as long as it is soluble in the mixed solvent. For example, LiClO ₄ , LiCl, LiBr, LBr
iI, LiBF ₄ , LiPF ₆ , LiCF ₃ SO ₃ , L
iAsF ₆ , LiAlCl ₄ , LiB (C ₆ H ₆ ) ₄ ,
CF ₃ SO ₃ Li, LiSbF ₆ , LiB ₁₀ Cl ₁₀ , L
iSiF ₆ , LiN (SO ₂ CF ₃ ) ₂ , LiC (SO
₂ CF ₃ ) ₂ , lithium lower fatty acid carboxylate, lithium chloroborane, lithium 4-phenylborate, and the like, and one or more of these lithium salts are used. The preferable addition amount of these lithium salts is 0.1 to 3 mol, preferably 0.5 to 1 kg of the solvent.
２2 mol.

The following compounds can be added to the electrolyte of the non-aqueous electrolyte battery of the present invention for the purpose of improving discharge and charge characteristics. For example, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphoric triamide, nitrobenzene derivative, sulfur, quinone imine dye,
N-substituted oxazolidinone and N, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, polyethylene glycol, pyrrole, 2-methoxyethanol, aluminum trichloride, conductive polymer electrode active material monomer, triethylenephosphonamide,
Examples include trialkylphosphine, morpholine, aryl compounds having a carbonyl group, hexamethylphosphoric triamide and 4-alkylmorpholine, bicyclic tertiary amines, oils, phosphonium salts and tertiary sulfonium salts.

The positive electrode of the nonaqueous electrolyte battery of the present invention
A positive electrode mixture consisting of a substance, conductive agent, binder, etc. is placed on the current collector.
And dried. Positive electrode active material
Therefore, there is no particular limitation, and known ones can be used.
For example, V_TwoO_Five, V_ThreeO ₁₃, V₆O₁₃, Mn
O_Two, MoO_ThreeMetal oxides such as LiCoO_Two, LiN
iO_Two , LiMn_TwoO_Four, LiMnO_Two, LiFeO_Two,
Lithium, Co, Ni, Mn, Fe, V, Mo, Cu
And at least two types of lithium selected from transition metals such as Zn
Complex metal oxides, halogenating these complex metal oxides
Compounds and other additives, TiS_Two, Mo
S_Two, FeS_Two, NbS_TwoSuch as metal sulfide, polypyrrole
Derivatives, polyaniline derivatives, polythiophene derivatives, etc.
Conductive polymers, graphite and the like.
It is preferable to use a titanium composite metal oxide.

The negative electrode of the non-aqueous electrolyte battery of the present invention is prepared by applying a negative electrode mixture containing a negative electrode active material and a binder on a current collector and drying. As the current collector, for example, a metal foil such as a copper foil is used. As the negative electrode material, known negative electrode materials can be used. For example, metallic lithium, an alloy of lithium and aluminum, indium, lead, or zinc, Ag ₂ O, TiO ₂ , Fe ₂ O ₃ , Mg
O, V ₂ O ₅ , NiO, CuO, ZnO, Mo ₂ O ₃ ,
In ₂ O ₃ , SnO, SnO ₂ , SnSiO ₃ , In ₂
Periodic Table Group 1, Group 2, Group 13, Group 14, Group 1 mainly composed of a crystalline composite oxide such as Sn ₂ O ₇ or tin oxide.
Examples thereof include an amorphous composite metal oxide containing at least one selected from Group V, transition metals, and halogen elements, and a carbon material that can be doped / dedoped with lithium. Among these, a carbon material capable of doping / dedoping lithium is preferable. Examples of such a carbon material include a non-graphitizable carbon material and a graphite-based carbon material. Specific examples include pyrolytic carbons, cokes, graphites, glassy carbon fibers, organic polymer material fired bodies, carbon fibers, activated carbon, and the like. Examples of the coke include pitch coke, petroleum coke, and coal coke. Here, the organic polymer material fired body is obtained by firing an organic polymer material such as a phenol resin or a furan resin at a desired temperature and carbonizing it.

A conductive agent, a binder, a filler, and the like can be added to the electrode mixture of the positive electrode mixture and the negative electrode mixture. The conductive agent is not particularly limited as long as it is an electron conductive material that does not cause a chemical change in the configured battery.For example, natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber and metal Examples thereof include conductive materials such as powder, metal fiber, and polyphenylene derivative, and these can be used as one kind or as a mixture of two or more kinds. As a binder,
Although not particularly limited, for example, starch, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, diacetyl cellulose, polyvinyl chloride, polyvinyl pyrrolidone, tetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, ethylene-propylene copolymer ( EPDM), sulfonated EPDM, styrene butadiene rubber, polybutadiene, fluorine rubber, polysaccharides such as polyethylene oxide, thermoplastic resins, and polymers having rubber elasticity. These are used as one kind or as a mixture of two or more kinds. .

The filler is not particularly limited as long as it is a fibrous material which does not cause a chemical change in the constructed battery, and usually includes olefin-based polymers such as polypropylene and polyethylene, and fibers such as glass and carbon.

In the non-aqueous electrolyte battery of the present invention, it is preferable to interpose a separator between the above-described positive electrode and negative electrode because current short-circuit due to contact between both electrodes can be prevented. Examples of the separator include a nonwoven fabric made of a synthetic resin such as polytetrafluoroethylene, polypropylene, and polyethylene, a thin film, and the like. Particularly, a microporous film of polypropylene or polyethylene having a thickness of about 20 to 50 μm is used. This is preferable in that the contact between the electrodes can be reliably prevented and the electrolyte can be passed through.

As other components of the nonaqueous electrolyte battery of the present invention, commonly used known components can be used. The form of the non-aqueous electrolyte secondary battery is not particularly limited, and may be a button type, a paper type,
There are various forms such as a coin type, a prismatic type or a spiral type cylindrical battery, and these can be formed in various sizes such as thin and large.

The non-aqueous electrolyte battery according to the present invention comprises a specific phosphazene derivative having a sulfonyl group in an electrolyte based on an organic solvent, and the mixing ratio with respect to the electrolyte is designed. Excellent performance. For example, in a non-aqueous electrolyte, usually 0.1 to
With a small addition amount of 20 v / v%, preferably 0.1 to 10 v / v%, decomposition of the electrolyte solution is suppressed without deteriorating the cycle characteristics due to the action as a base, and the storage characteristics at high temperatures are particularly excellent. Further, in a non-aqueous electrolyte, usually 1-80v
/ V%, preferably in the range of 10 to 40 v / v%, it is possible to impart flame retardancy to the electrolyte solution and sufficiently reduce the risk of rupture or ignition of the battery.

[0033]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but this is merely an example and does not limit the present invention. Reference Example 1 (Preparation of phosphazene derivative A) 46.6 g of phosphorus pentachloride in a four-necked flask equipped with a stirrer
(0.224 mol), 21.3 g of methanesulfonamide
(0.224 mol), 62.9 g of dehydrated toluene and TH
0.2 g of F was charged and reacted at room temperature under a nitrogen atmosphere for 2 hours to obtain trichlorophosphazosulfonylmethane.
After completion of the reaction, the solution was used as a raw material as it was. 27.8 g of sodium hydride in a four-necked flask equipped with a stirrer
(0.695 mol) and 233.5 g of dehydrated THF were charged, and then 136.9 g (1.13 mol) of diethylene glycol monomethyl ether was added dropwise to prepare an alcoholate solution of diethylene glycol monomethyl ether. In a four-necked flask equipped with a stirrer, 51.6 g (0.224 mol) of trichlorophosphazosulfonylmethane was added.
And 225.6 g of toluene were charged, and in a nitrogen atmosphere, the alcoholate solution of diethylene glycol monomethyl ether (0.695 mol) prepared above was added dropwise while maintaining the temperature in the reaction system at 0 to 10 ° C. After dropping,
Further, the reaction was carried out under stirring at a temperature of 10 ° C. or lower for 1.5 hours. After the completion of the reaction, the mixture was neutralized with acetic acid. Next, the mixture was filtered, and the filtrate was extracted with chloroform. The obtained organic layer was concentrated and dehydrated to obtain 37.7 g (yield: 83.1%) of an oily substance. Elemental analysis, ¹ H-NMR, ³¹ P-NMR, MASS
As a result, the phosphazene derivative A having a sulfonyl group shown in Table 1 was confirmed.

(Identification data) Elemental analysis: Structural formula: C ₁₆ H ₃₆ NO ₁₁ PS (molecular weight: 481.
39.94%, H: 7.54%, N: 2.91%, S; 6.
66% actual value; C: 39.71%, H: 8.01%, N: 2.89%, S: 6.
86% ¹ H-NMR (ppm, CDCl ₃ ) δ; 3.01 (d, 3H), 3.40
(m, 9H), 3.53 (m, 6H), 3.65 (m, 6H), 3.74 (m, 6H), 4.37 (
m, 6H) ³¹ P-NMR (ppm, CDCl ₃ ) δ; -1.81 (m) IR; ν (KBr) cm ^-1 ; 2882, 1455, 1328, 1220,
1143, 1111 ・ MASS (FAB) m / z; 482 (M + H) ⁺

Reference Example 2 (Preparation of phosphazene derivative B) In a four-necked flask equipped with a stirrer, 31.4 g of phosphorus pentachloride was added.
(0.151 mol), benzenesulfonamide 23.6
g (0.150 mol), 74.3 g of dehydrated toluene and T
HF (1.0 g) was charged and reacted under stirring at room temperature for 2.5 hours, and trichlorophosphazosulfonylbenzene was added.
5 g was obtained (96.9% yield). A four-necked flask equipped with a stirrer was charged with 17.9 g (0.449 mol) of sodium hydride and 153.3 g of dehydrated THF, and then 58.2 g of ethylene glycol monomethyl ether (0.
764 mol) was added dropwise to prepare an alcoholate solution of ethylene glycol monomethyl ether. In a four-necked flask equipped with a stirrer, 42.69 g (0.146 mol) of the above-prepared trichlorophosphazosulfonylbenzene and 145.1 g of toluene were charged, and in a nitrogen atmosphere, the alcoholate of ethylene glycol monomethyl ether prepared above was charged. The solution (0.449 mol) was added dropwise while maintaining the temperature in the reaction system at 0 to 10 ° C. After the completion of the dropwise addition, the mixture was further reacted under stirring at room temperature for 3.5 hours. After completion of the reaction, the mixture was neutralized with hydrochloric acid. Then, the mixture was filtered, the filtrate was extracted with dichloromethane, and the obtained organic layer was concentrated and dehydrated to obtain 47.1 g (yield: 78.4%) of an oily substance. Elemental analysis, ¹ H-NMR, ³¹ P-NMR, MASS and I
When identified by R, it was confirmed to be the phosphazene derivative B having a sulfonyl group shown in Table 1.

(Identification data) Elemental analysis: Structural formula C ₁₅ H ₂₆ NO ₈ PS (molecular weight 411.3)
43.79%, H; 6.37%, N; 3.40%, S; 7.
C: 43.71%, H: 6.59%, N: 3.54%, S: 8.
02% ¹ H-NMR (ppm, CDCl ₃ ) δ; 3.35 (s, 9H), 3.58
(m, 6H), 4.32 ( m, 6H), 7.47 (m, 3H), 7.96 (m, 2H) · 31 P-NMR (ppm, CDCl 3) δ; -2.01 (m) · IR; ν (KBr ) Cm ^-1 ν; 2890, 2824, 1447, 1370,
1203, 1155, 1133 ・ MASS (FAB) m / z; 412 (M + H) ⁺

Example 3 (Preparation of Phosphazene Derivative C) 46.2 g of phosphorus pentachloride was placed in a four-necked flask equipped with a stirrer.
(0.222 mol), 39.1 g (0.222 mol) of 4-fluorobenzenesulfonamide, 8.0 g of tetrahydrofuran and 250 ml of toluene were charged and reacted in a nitrogen atmosphere for 2 hours at room temperature. After completion of the reaction, the solvent was distilled off, and N-4-fluorobenzenesulfonyl-P,
66.1 g of P, P-trichlorophosphazene (yield 9
5.6%). Next, 60.0 g of N-4-fluorobenzenesulfonyl-P, P, P-trichlorophosphazene obtained above was placed in a four-necked flask equipped with a stirrer.
(0.193 mol) and 250 mL of tetrahydrofuran, and an alcoholate solution of ethylene glycol monomethyl ether (0.63) obtained in the same manner as in Reference Example 2.
7 mol) in a nitrogen atmosphere at 0-5 ° C. with stirring overnight. After completion of the reaction, the mixture was neutralized with concentrated sulfuric acid. Next, after washing with water, the organic layer obtained by extraction with chloroform was concentrated and dehydrated to give 75.2 g of an oily substance (yield 7).
8.9%). Elemental analysis, ¹ H-NMR, ³¹ PN
As a result of identification by MR, MASS and IR, it was confirmed that the compound was a phosphazene derivative C having a sulfonyl group shown in Table 1.

(Identification data) Elemental analysis: Structural formula C ₁₅ H ₂₅ FNO ₈ PS (molecular weight 429.4
Calculated for C): 41.95%, H: 5.87%, N: 3.26%, S: 7.
47% found; C; 42.34%, H: 6.16%, N: 3.36%, S; 7.
79% ¹ H-NMR (ppm, CDCl ₃ ) δ; 3.24 (s, 9H), 3.45
(m, 6H), 4.17 ( m, 6H), 6.99 (m, 2H), 7.86ppm (m, 2H) · 31 P-NMR (ppm, CDCl 3) δ; -2.2 (m) · IR; ν ( KBr) cm ^-1 ; 2932, 2890, 1591, 1494, 1
371, 1280, 1218, 1150, 1039, 839, 687 MASS (APCl) m / z: 430 (M + H) ⁺

Reference Example 4 (Preparation of phosphazene derivative C) 10.6 g of phosphorus pentachloride was placed in a four-necked flask equipped with a stirrer.
(0.051 mol), 10.0 g (0.052 mol) of 2,4-difluorobenzenesulfonamide, 1.4 g of tetrahydrofuran and 100 ml of toluene were charged and reacted in a nitrogen atmosphere for 2 hours at room temperature. After the reaction,
The solvent was distilled off, and N-2,4-difluorobenzenesulfonyl-P, P, P-trichlorophosphazene was 16.1 g.
(96.2% yield). Next, 16.1 g (0.0490 mol) of N-2,4-difluorobenzenesulfonyl-P, P, P-trichlorophosphazene obtained above and 100 mL of tetrahydrofuran were charged into a four-necked flask equipped with a stirrer. The alcoholate solution (0.160 mol) of ethylene glycol monomethyl ether obtained in the same manner as in Example 2 was reacted in a nitrogen atmosphere at 0 to 5 ° C. with stirring overnight. After completion of the reaction, the mixture was neutralized with concentrated sulfuric acid. Next, after washing with water, the organic layer obtained by extraction with chloroform was concentrated and dehydrated to obtain 17.0 g of an oily substance.
(77.7% yield). Elemental analysis, ¹ H-NMR,
^When identified by ³¹ P-NMR, MASS and IR, it was confirmed to be a phosphazene derivative D having a sulfonyl group shown in Table 1.

(Identification data) Elemental analysis: Structural formula C ₁₅ H ₂₄ F ₂ NO ₈ PS (molecular weight: 44
7.4) Calculated values for C; 40.27%, H; 5.41%, N; 3.13%, S;
C: 40.24%, H: 5.48%, N: 3.16%, S: 7.
54% ¹ H-NMR (ppm, CDCl ₃ ) δ; 3.27 (s, 9H), 3.51
(m, 6H), 4.25 ( m, 6H), 6.83 (m, 2H), 7.89 (m, 1H) · 31 P-NMR (ppm, CDCl 3) δ; -2.58 (m) · IR; ν (KBr ) Cm ^-1 ; 2893, 2825, 1603, 1485, 1
424, 1372, 1290, 1203, 1159, 1040, 970, 850, 68
7, 620 MASS (APCl) m / z: 448 (M + H) ⁺

[0041]

[Table 1]

Examples 1 to 5 and Comparative Example 1 0.5 mol of lithium carbonate and 1 mol of cobalt carbonate were mixed and fired in air at 900 ° C. for 5 hours to obtain LiCoO ₂ as a positive electrode active material. Using LiCoO ₂ as a positive electrode active material, 100 parts by weight of LiCoO ₂ were added with 10 parts by weight of acetylene black as a conductive aid and 10 parts by weight of Teflon (registered trademark) binder as a binder to prepare a positive electrode material. did. Using metallic lithium as the negative electrode material,
The phosphazene derivative A prepared in the above reference example was prepared by using a porous film of polypropylene as a separator and using a commercially available aprotic organic solvent (a mixture of ethylene carbonate and diethyl carbonate (EC + DEC) manufactured by Toyama Pharmaceutical Co., Ltd.) as an electrolyte. To D were added at the compounding ratios shown in Table 2 to prepare coin-type non-aqueous electrolyte secondary batteries. The mixing ratio indicates the volume ratio of the phosphazene derivative in the non-aqueous electrolyte. A coin-type non-aqueous electrolyte secondary battery containing no phosphazene derivative in the electrolyte was prepared as Comparative Example 1. With respect to the battery prepared above, the initial discharge capacity, the discharge capacity at 20 cycles, the discharge capacity maintenance ratio, and the state at the time of external short circuit shown below were evaluated. The results are shown in Table 2.

(Discharge Capacity and Discharge Capacity Maintenance Ratio) A cycle test in which charge and discharge are repeated under the conditions of an upper limit voltage of 4.3 V, a lower limit voltage of 2.7 V, a discharge current of 0.2 mA, and a charge current of 0.2 mA was performed. Discharge capacity (initial discharge capacity)
(MAh) and the discharge capacity (mAh) at 20 cycles. Further, the discharge capacity retention ratio is obtained by the following equation. Discharge capacity retention rate (%) = Discharge capacity at 20 cycles x 100 /
(Initial discharge capacity)

(State at the time of external short circuit) After charging and discharging for 5 cycles and charging to 3.0 V, both the positive and negative electrodes are connected by a lead wire and external short circuit is performed. The five batteries at this time are checked for any change in battery appearance.

[0045]

[Table 2]

As is clear from Table 2, the conventional secondary battery using an aprotic organic solvent as an electrolyte solvent was deformed at the time of short circuit (Comparative Example 1), but had a sulfonyl group. The secondary batteries of Examples 1 to 5 using the mixed solvent containing the specific phosphazene derivative did not leak, rupture or ignite even at the time of short circuit, and the battery performance showed a result equal to or higher than that of the conventional battery. .

Examples 6 to 9 <Preparation of Cylindrical Nonaqueous Electrolyte Battery> Negative Electrode Using a petroleum pitch as a starting material, a negative
By baking at 0 ° C., a non-graphitizable carbon material having properties similar to glassy carbon was obtained. X-ray diffraction measurement of this non-graphitizable carbon material revealed that the west spacing of the (002) plane was 3.76 Å, and the true specific gravity was 1.58 g /
cm ² . Next, the obtained non-graphitizable carbon material was pulverized to obtain a carbon material powder having an average particle diameter of 10 μm. 90 parts by weight of this carbon material powder and 10 parts by weight of a binder were mixed to prepare a negative electrode mixture. Here, polyvinylidene fluoride was used as the binder. Finally, the negative electrode mixture was dispersed in N-methyl-2-pyrrolidone to form a slurry. Then, the slurry was uniformly applied to both surfaces of a 10 μm-thick strip-shaped copper foil as a negative electrode current collector, dried to form a negative electrode active material layer, and then compression-molded with a roll press to prepare a negative electrode. .

Positive electrode 0.5 mol of lithium carbonate and 1 mol of cobalt carbonate were mixed and calcined in air at 900 ° C. for 5 hours to obtain LiCoO ₂ as a positive electrode active material. Next, 91 parts by weight of the obtained LiCoO ₂ , 6 parts by weight of a conductive agent, and 10 parts by weight of a binder were mixed to prepare a positive electrode mixture. Here, graphite is used as the conductive agent,
As the binder, a copolymer of vinylidene fluoride and hexafluoropropylene was used. Finally, the positive electrode mixture is
The slurry was dispersed in N-methyl-2-pyrrolidone to form a slurry, and this slurry was used as a positive electrode current collector to a thickness of 20%.
A positive electrode was formed by uniformly coating and drying both surfaces of a μm aluminum foil to form a positive electrode active material layer, followed by compression molding with a roll press.

Using the positive electrode and the negative electrode obtained as described above, a non-aqueous electrolyte battery shown in FIG. 1 was produced. That is, the positive electrode 2 and the negative electrode 3 were brought into close contact with each other through a separator 4 made of microporous polypropylene having a thickness of 25 μm, and wound in a spiral shape many times to form a wound layer body. next,
An insulating plate 6 was inserted into the bottom of a nickel-plated iron battery can 5 inside, and the wound body obtained above was stored. Then, in order to collect the current of the negative electrode 3, one end of a nickel negative electrode lead 7 was pressed against the negative electrode 3, and the other end was welded to the battery can 5. One end of an aluminum positive electrode lead 8 is connected to the positive electrode 2 in order to collect the current of the positive electrode 2.
, And the other end was electrically connected to the battery lid 10 via the current interrupting thin plate 9. This current interrupting thin plate 9
Is to cut off the current according to the internal pressure of the battery.

Next, a non-aqueous electrolyte was injected into the battery can 5. As a solvent for the non-aqueous electrolyte, a mixed solution composed of 50% by volume of ethylene carbonate and 50% by volume of diethyl carbonate was used.
As the volume%, those obtained by adding the various phosphazene derivative samples prepared as described above in the mixing ratio shown in Table 3 were used. The blending amount of the phosphazene derivative is represented by a volume ratio (%) in the electrolytic solution. Finally, the battery lid 10 is fixed by caulking the battery can 5 through an insulating sealing gasket 11 coated with asphalt, and has a diameter of about 18 mm and a height of about 6 mm.
A 5 mm cylindrical nonaqueous electrolyte battery 1 was prepared. In addition, the nonaqueous electrolyte battery 1 is provided with a center pin 12 connected to the negative electrode lead 7 and the positive electrode lead 8, and to release the gas inside the battery when the pressure inside the battery becomes higher than a predetermined value. And a PTC element 14 for preventing the temperature inside the battery from rising.

[0051]

[Table 3]

Comparative Example 2 A non-aqueous electrolyte battery was prepared in the same manner as in Examples 6 to 9, except that the phosphazene derivative was not added to the electrolyte.

Comparative Example 3 A non-aqueous electrolyte battery was operated in the same manner as in Examples 6 to 9 except that 1% by volume of basic pyridine was added to the electrolyte as a neutralizing agent for the free acid instead of the phosphazene derivative. It was created.

Comparative Example 4 A non-aqueous electrolyte battery was prepared in the same manner as in Examples 6 to 9, except that 3% by weight of tributyl phosphate was added to the electrolyte instead of the phosphazene derivative.

For the non-aqueous electrolyte batteries prepared in Examples 6 to 9 and Comparative Examples 2 to 4, the initial capacity, load characteristics,
The discharge capacity retention after the cycle and the high-temperature storage characteristics (self-discharge characteristics) were evaluated, and the results are shown in Table 4. In addition,
Each evaluation method is as follows.

(Initial capacity) Each non-aqueous electrolyte battery prepared above was charged at a constant current of 1 A at a constant current and a constant voltage of up to 4.2 V for 3 hours at 23 ° C., and then at 1000 mA.
At a final voltage of 2.5 V to obtain an initial capacity.

(Load Characteristics) One cycle of charging / discharging was performed under the same charging conditions as the initial capacity, and after performing the same charging,
A constant current discharge of 2000 mA is performed up to a final voltage of 2.5 V, and a discharge capacity of 700 mA is assumed to be 100.
A discharge capacity maintenance rate (%) of 0 mA was determined.

(Discharge capacity retention ratio) The discharge and charge were performed 100 cycles under the same charging conditions as the initial capacity described above, and the ratio of the discharge capacity at the 100th cycle to the initial discharge capacity was determined.

(High-Temperature Storage Characteristics) After charging under the same charging conditions as the initial capacity described above, the battery was left in an atmosphere of 60 ° C., and the battery was taken out after 10 days. Next, 5 hours after the battery was taken out, discharging was performed at 23 ° C. and 700 mA. Then, the discharge capacity retention ratio after storage with respect to the discharge capacity before being left in an atmosphere at 60 ° C. was determined, and the difference was determined as the self-discharge rate. In addition, a smaller value indicates that the high-temperature storage characteristics are superior.

[0060]

[Table 4]

As is clear from the results in Table 4, the battery in which the phosphazene derivative of the present invention was added to the non-aqueous electrolyte was
The initial capacity of the battery was large, and the discharge capacity maintenance ratio of 2000 mA with respect to the discharge capacity of 700 mA was high, resulting in particularly excellent high-temperature storage characteristics. Also, the cycle characteristics were at a level without any problem.

Example 10 The phosphazene derivatives E to P shown in Table 5 were prepared according to Reference Examples 1 to 4, and nonaqueous electrolyte batteries were prepared in the same manner as in Examples 6 to 9; The discharge capacity retention rate after 100 cycles and the high-temperature storage characteristics (self-discharge characteristics) were evaluated. Table 6 shows the results. In the case of the phosphazene derivative E, the sulfonamide used in the reaction formula (I) is methanesulfonamide, and the alcoholate used in the reaction formula (II) is a sodium salt of methyl alcohol. In the case of the derivative F, the sulfonamide used in the reaction formula (I) is methanesulfonamide, and the alcoholates used in the reaction formula (II) are a sodium salt of trifluoroethyl alcohol. In the case of G, the sulfonamide used in the reaction formula (I) is methanesulfonamide, and the alcoholate used in the reaction formula (II) is a sodium salt of ethylene glycol monofluoromethyl ether; In the case of derivative H, the sulfonamide used in the above reaction formula (I) is methanesulfo The alkoxides used in the reaction formula (II) are sodium salts of ethylene glycol monofluoroethyl ether. In the case of the phosphazene derivative I, the sulfonamide used in the reaction formula (I) is Alcoholates which are methanesulfonamides and which are used in the above reaction formula (II) are sodium salts of ethylene glycol monofluoroethyl ether.

In the case of the phosphazene derivative J, the sulfonamide used in the reaction formula (I) is benzenesulfonamide, and the alcoholate used in the reaction formula (II) is a sodium salt of methyl alcohol. In the case of the phosphazene derivative K, the sulfonamide used in the reaction formula (I) is benzenesulfonamide, and the alcoholates used in the reaction formula (II) are:
In the case of the sodium salt of trifluoroethyl alcohol and the phosphazene derivative L, the sulfonamide used in the reaction formula (I) is benzenesulfonamide, and the alcoholates used in the reaction formula (II) are ethylene oxide. It is a sodium salt of glycol monofluoroethyl ether.

Further, in the case of the phosphazene derivative M,
The sulfonamide used in the reaction formula (I) is parafluorobenzenesulfonamide, and the reaction formula (I)
The alcoholates used in I) are sodium salts of trifluoroethyl alcohol. In the case of the phosphazene derivative N, the sulfonamide used in the above reaction formula (I) is 2,5-difluorobenzenesulfonamide, The alcoholates used in the reaction formula (II) are sodium salts of ethylene glycol monomethyl ether. In the case of the phosphazene derivative O, the sulfonamide used in the reaction formula (I) is 2,6-difluorobenzenesulfone. The alkoxides used in the reaction formula (II) are sodium salts of ethylene glycol monomethyl ether. In the case of the phosphazene derivative P, the sulfonamide used in the reaction formula (I) is 3,3.
5-Difluorobenzenesulfonamide, and the alcoholate used in the above reaction formula (II) is ethylene glycol monomethyl ether.

[0065]

[Table 5]

[0066]

[Table 6]

Examples 22 to 24 The phosphazene derivative samples B, G, and P were used as a solvent for the nonaqueous electrolyte at a volume ratio of 100% by volume of a mixture of 50% by volume of ethylene carbonate and 50% by volume of diethyl carbonate. %, And as a constituent material of the negative electrode, instead of the non-graphitizable carbon material used in Examples 6 to 9, graphite (manufactured by Lonza Co., Ltd., trade name: KS-75-002, spacing between surfaces = 3) .
358 Angstroms) and the others were used in Examples 6-9.
A cylindrical non-aqueous electrolyte battery was prepared in the same manner as described above.

Comparative Example 5 A cylindrical nonaqueous electrolyte battery was prepared in the same manner as in Examples 22 to 24 except that the phosphazene sample was not added to the electrolyte.

In the same manner as in Examples 6 to 9, the cylindrical nonaqueous electrolyte batteries prepared in Examples 22 to 24 and Comparative Example 5 were subjected to initial capacity, load characteristics, discharge capacity retention after 100 cycles, and high-temperature storage characteristics ( The self-discharge characteristics were evaluated, and the results are shown in Table 7.

[0070]

[Table 7]

From the results shown in Table 7, even when graphite was used as the negative electrode material, the initial capacity of the battery was larger when the phosphazene derivative of the present invention was added to the nonaqueous electrolyte than when it was not added. Moreover, the discharge capacity maintenance ratio of 2000 mA with respect to the discharge capacity of 700 mA is high,
Very good results. In addition, the cycle characteristics and the high-temperature storage stability were also good.

[0072]

According to the non-aqueous electrolyte battery of the present invention, the vaporization and decomposition of the organic solvent-based electrolyte are suppressed over a wide temperature range, and the high-temperature storage characteristics are particularly excellent, and the ignition and ignition are prevented. There is a great effect that there is little danger and excellent battery performance.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one configuration example of a nonaqueous electrolyte battery according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Non-aqueous electrolyte battery 2 Positive electrode 3 Negative electrode 4 Separator 5 Battery can 6 Insulating plate 7 Negative lead 8 Positive electrode lead 9 Current cut-off thin plate negative electrode current collector 10 Battery lid 11 Insulation sealing gasket 12 Center pin 13 Safety valve device 14 PTC element

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tadashi Saito 9-11-1, Kameido, Koto-ku, Tokyo Nippon Kagaku Kogyo Co., Ltd. Research and Development Headquarters (72) Inventor Nobuhiko Ohara 9-11 Kameido, Koto-ku, Tokyo No. 1 Nippon Kagaku Kogyo Co., Ltd. Research and Development Headquarters (72) Inventor Jun Wakui 9-11-1, Kameido, Koto-ku, Tokyo Nippon Kagaku Kogyo Co., Ltd. Research and Development Headquarters (72) Inventor Tomohisa Kamata Tokyo 9-11-11 Kameido, Koto-ku Nippon Kagaku Kogyo Co., Ltd. Research and Development Division F-term (reference) 5H029 AJ04 AJ05 AJ07 AJ12 AK02 AK03 AK04 AK05 AK07 AK16 AK18 AL02 AL03 AL06 AL07 AL08 AL12 AM02 AM03 AM04 AM05 AM07 BJ02 BJ08 DJ DJ09 EJ11 HJ01 HJ02 5H050 AA07 AA09 AA13 AA15 BA17 CA02 CA07 CA08 CA09 CA10 CA11 CA15 CA29 CB02 CB03 CB07 CB08 CB09 CB12 DA09 DA13 EA22 HA01 HA02

Claims (5)

[Claims] 1. A non-aqueous electrolyte battery comprising a positive electrode, a negative electrode capable of occluding or releasing lithium ions, and a non-aqueous electrolyte containing lithium ions, wherein the non-aqueous electrolyte has the following general formula (1) (R ¹ O) ₃ P = N—SO ₂ —R ² (1) wherein R ¹ is a linear or branched alkyl having 1 to 10 carbon atoms which may be substituted with a halogen atom; A group represented by the following formula, which may be substituted with a group or a halogen atom; CH _3- (
OCH ₂ CH ₂ ) _n − (n represents an integer of 1 to 5), and R ² represents an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom, or a halogen atom, an alkoxy group or A phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms is shown. A non-aqueous electrolyte battery comprising a solution containing a phosphazene derivative represented by｝ and a lithium salt. 2. The non-aqueous electrolyte is a solution in which a lithium salt is dissolved in a mixed solvent obtained by mixing the phosphazene derivative and an aprotic organic solvent.
The non-aqueous electrolyte battery according to the above. 3. The non-aqueous electrolysis according to claim 1, wherein the content of the phosphazene derivative in the non-aqueous electrolyte is in the range of 0.1 to 80 v / v% by volume. Liquid battery. 4. The positive electrode according to claim 1, wherein a composite metal oxide of lithium and a transition metal is used as an active material.
The nonaqueous electrolyte battery according to any one of the above. 5. The non-aqueous electrolyte battery according to claim 1, wherein the negative electrode capable of inserting or extracting lithium ions is a carbon material.