JP5842379B2 - Non-aqueous electrolyte secondary battery - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte secondary battery, and more specifically, a non-aqueous electrolyte containing a specific cyclic compound having a triple bond as an electrolyte and a negative electrode comprising graphite having a specific ratio of rhombohedral crystal in the negative electrode The present invention relates to a non-aqueous electrolyte secondary battery containing an active material.

  Non-aqueous electrolyte secondary batteries such as lithium secondary batteries are widely used as power sources for so-called portable electronic devices such as mobile phones and notebook computers, to in-vehicle power sources for automobiles and large power sources for stationary applications. It is being put into practical use. However, with the recent high performance of electronic devices and the application to in-vehicle power supplies for driving and large power supplies for stationary applications, the demand for applied secondary batteries is increasing, and the high performance of the battery characteristics of secondary batteries is increasing. For example, it is required to achieve high levels of improvement in capacity, high temperature storage characteristics, cycle characteristics, and the like.

  The electrolyte used for the non-aqueous electrolyte lithium secondary battery is usually composed mainly of an electrolyte and a non-aqueous solvent. The main components of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate and propylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate; cyclic carboxylic acid esters such as γ-butyrolactone and γ-valerolactone. It is used.

  In addition, various non-aqueous solvents, electrolytes, additives, and other additives are also proposed to improve battery characteristics such as load characteristics, cycle characteristics, storage characteristics, and low-temperature characteristics of batteries using these non-aqueous electrolytes. Has been. For example, in a non-aqueous electrolyte using carbon as the negative electrode active material, by using vinylene carbonate and its derivatives or vinyl ethylene carbonate derivatives, the cyclic carbonate having a double bond reacts preferentially with the negative electrode surface. Patent Documents 1 and 2 disclose that a high-quality film is formed on the battery, thereby improving the storage characteristics and cycle characteristics of the battery.

  In addition, for example, in a non-aqueous electrolyte using artificial graphite as a negative electrode active material, by combining a specific ethylene carbonate derivative with a triple bond-containing compound and / or a pentafluorophenyloxy compound, gas generation is reduced and cycle characteristics are reduced. It is disclosed in Patent Document 3 that the above is improved.

JP-A-8-45545 JP-A-4-87156 WO 2006-077763

As described above, in recent years, the demand for higher performance of secondary batteries is increasing, and thus the characteristics of lithium secondary batteries have been improved, that is, higher capacity, higher temperature storage characteristics, cycle characteristics and the like have been demanded.
Under such a background, Patent Documents 1 and 2 disclose that a nonaqueous electrolyte secondary battery using carbon as a negative electrode active material and a cyclic carbonate having a double bond as a nonaqueous electrolyte protects the electrode surface. Thus, it is described that battery durability such as storage characteristics and cycle characteristics is improved. However, when a charged battery is left at a high temperature or a continuous charge / discharge cycle is performed, there is a problem in that unsaturated cyclic carbonate or a derivative thereof is oxidized and decomposed on the positive electrode to generate carbon dioxide gas. If carbon dioxide gas is generated in such a use environment, the battery itself may become unusable due to, for example, activation of a battery safety valve or expansion of the battery.

  In addition, the oxidative decomposition of unsaturated cyclic carbonate on the positive electrode causes a problem of generating a solid decomposition product in addition to the generation of carbon dioxide gas. Generation of such a solid decomposition product causes clogging of the electrode layer and the separator to inhibit the movement of lithium ions, or the solid decomposition product remains on the surface of the electrode active material and causes the lithium ion insertion / release reaction. May interfere. As a result, for example, the charge / discharge capacity may gradually decrease during the continuous charge / discharge cycle, the charge / discharge capacity may decrease from the initial stage after storage at a high temperature of the battery or after the continuous charge / discharge cycle, or the load characteristics may deteriorate.

  Also, the oxidative decomposition of unsaturated cyclic carbonate on the positive electrode becomes a particularly serious problem under the recent high performance secondary battery design. That is, this oxidative decomposition tends to become prominent when the redox potential of lithium, which is the potential at which the positive electrode active material inserts and desorbs lithium, increases. For example, when an attempt is made to operate at a voltage higher than 4.2 V, which is a battery voltage at the time of full charge of a secondary battery currently on the market, these oxidation reactions are particularly prominent.

In addition, in a non-aqueous electrolyte secondary battery described in Patent Document 3 using artificial graphite as a negative electrode active material and using a triple bond-containing compound as a non-aqueous electrolyte, non-aqueous electrolyte is used to improve cycle characteristics. A triple bond-containing compound or the like is used as the electrolyte. However, if the electrode density is increased to increase the capacity, there is a problem that the reactivity with the electrolytic solution is large and the cycle characteristics are difficult to improve.
Therefore, the present invention eliminates the above-mentioned various problems that occur when trying to achieve the performance required for secondary batteries in recent years, and in particular, non-aqueous electrolysis with improved durability characteristics such as cycle and storage. It is to provide a liquid secondary battery.

Invention have found, after intensive studies to solve the above problems, a negative electrode for use in a nonaqueous electrolyte secondary battery, the 1360 cm ^-1 to the peak intensity of 1580 cm ^-1 in the argon ion laser Raman spectroscopy A negative active material containing at least one carbonaceous material having a Raman R value of 0.1 or more defined as a ratio of peak intensities, and the non-aqueous electrolyte is represented by the following general formula (1) It was found that a nonaqueous electrolyte secondary battery with improved durability characteristics such as cycle and storage can be realized by including at least one selected from the group consisting of the above compounds, and the present invention has been completed. .

That is, the gist of the present invention is as follows.
A non-aqueous electrolyte secondary battery comprising a non-aqueous electrolyte solution containing a lithium salt and a non-aqueous solvent for dissolving the lithium salt, a negative electrode capable of occluding and releasing lithium ions, and a positive electrode,
The negative electrode, the Raman R value, defined as the ratio of the peak intensity of 1360 cm ^-1 to the peak intensity of 1580 cm ^-1 in the argon ion laser Raman spectroscopy to contain at least one or more carbonaceous material is 0.1 or more The present invention resides in a non-aqueous electrolyte secondary battery including a negative electrode active material, and wherein the non-aqueous electrolyte contains a compound represented by the following general formula (1).

(Wherein X and Z represent CR ¹ ₂ , C═O, C═N—R ¹ , C═P—R ¹ , O, S, N—R ¹ , P—R ¹ , and are the same or different. Y represents CR ¹ ₂ , C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ³ where R and R ¹ is hydrogen, halogen, or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same or different from each other, and R ² has a functional group. Or a hydrocarbon group having 1 to 20 carbon atoms, wherein R ³ is Li, NR ⁴ ₄ or 1 carbon atom which may have a functional group.
To 20 hydrocarbon groups. R ⁴ is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same as or different from each other. n and m represent an integer of 0 or more. W is a range having the same meaning as R, and W may be the same as or different from R. )
The carbonaceous material preferably has an interlayer distance d002 of 0.335 nm or more and 0.339 nm or less,
The carbonaceous material preferably includes one or more selected from the group consisting of a carbonaceous material obtained by coating carbon with nuclear graphite, a carbonaceous material obtained by coating graphite with nuclear graphite, and a natural carbonaceous material,
The compound represented by the general formula (1) is preferably a compound represented by the formula (2),

(Y represents C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ³ , where R ² may have a functional group. It is a hydrocarbon group of the number 1 to 20. R ³ is Li,
NR ⁴ ₄ or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group. R ⁴ is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same as or different from each other. )
In addition, the non-aqueous electrolyte is (A) Li _α XO _n F _m (X = any element of Groups 13, 15, 16 in the second or third period of the periodic table, α = 1-2, n = 1) ~ 3, m = 1 ~ 2) is preferably contained,
The non-aqueous electrolyte preferably contains (B) a compound represented by the following general formula (3),

(In the general formula (3), A represents an alkali metal, M is a transition metal, a group 13, 14 or 15 element of the periodic table, b is 1 to 3, m is 1 to 3, and n is 0 to 6, q represents 0 or 1, respectively, and R ⁵ represents alkylene having 1 to 10 carbons, halogenated alkylene having 1 to 10 carbons, arylene having 6 to 20 carbons, or 6 to 20 carbons. A halogenated arylene (these alkylene and arylene may have a substituent or a hetero atom in the structure thereof, and m R ^{5 s} may be bonded to each other), and R ⁶ is , Halogen, alkyl having 1 to 10 carbons, alkyl halide having 1 to 10 carbons, aryl having 6 to 20 carbons, halogenated aryl having 6 to 20 carbons, or X ³ R ⁷ (these alkyls and aryls) Is The structure may have a substituent or a heteroatom, and n R ^{6 s} may be bonded to each other to form a ring.), X ¹ , X ² , X ³ Is O, S, or NR ⁸ , and R ⁷ and R ⁸ are each independently hydrogen, alkyl having 1 to 10 carbons, halogenated alkyl having 1 to 10 carbons, or 6 to 20 carbons Aryl, or an aryl halide having 6 to 20 carbon atoms (these alkyl and aryl may have a substituent or a hetero atom in the structure, or a plurality of R ⁷ and R ⁸ are bonded to each other) And may form a ring.))
The non-aqueous electrolyte preferably contains (C) a carbonate having at least one of a carbon-carbon unsaturated bond or a fluorine atom.

The present invention provides a non-aqueous electrolyte battery in which durability characteristics such as battery cycle and storage are improved particularly in the design of a lithium secondary battery with high voltage and high capacity. The reason for this is estimated as follows.
In the present invention, a compound in which a carbon-carbon triple bond is bonded to a ring structure by a single bond without intervening other functional groups or heteroelements is used for a non-aqueous electrolyte, and a Raman R value (hereinafter referred to as a Raman value). One of the characteristics is that a negative electrode active material composed of carbon particles having a particle size of 0.1 or more is used for a non-aqueous electrolyte battery. Usually, as typified by Patent Documents 1 and 2, many of the materials that protect the electrode surface and improve battery durability such as storage characteristics and cycle characteristics are compounds of a cyclic structure, and further have multiple bonding sites. Have. The present inventors paid attention to this point, and examined in detail the bonding sites of functional groups and heteroelements in the ring structure, the sites where multiple bonds are bonded to the ring structure, and the hybrid state of the electron orbits of the multiple bonds. As a result, for example, a compound in which multiple bonds are bonded to a ring structure is superior to a compound in which a part of the ring skeleton constituting the cyclic compound is a multiple bond, When the carbon-carbon triple bond substituent is bonded to the ring structure, it is easier to form a stable electrode protective film on the negative electrode surface than the carbon-carbon double bond. On the other hand, even a compound having a carbon-carbon triple bond as described in Patent Document 3 is a chain compound, the degree of polymerization is difficult to extend, and stability as an electrode protective film cannot be obtained. Therefore, the remarkable effect of improving battery durability is not confirmed (see, for example, Example 6 and Comparative Example 7).

Moreover, the film formation process by the decomposition | disassembly, superposition | polymerization, etc. on the negative electrode surface of the cyclic compound containing a carbon-carbon multiple bond is strongly dependent also on the surface physical property of a negative electrode active material. As one of parameters defining the surface properties of the carbonaceous negative electrode, the Raman R value, defined as the ratio of the peak intensity of 1360 cm ^-1 to the peak intensity of 1580 cm ^-1 in the argon ion laser Raman spectrum method. The inventors have studied in detail the Raman R value and decomposition products on the carbonaceous negative electrode, and found that the compound represented by the general formula (1) together with the carbonaceous material having a Raman R value of 0.1 or more. As a result, it was found that a synergistic effect excellent in battery durability characteristics was obtained. The reason for this is not clear at present, but the decomposition reactivity and polymerizability of the compound of the general formula (1) strongly depend on the negative electrode surface properties defined by the Raman R value, and are extremely stable on the negative electrode surface. Provided is a non-aqueous electrolyte battery in which a durable electrode protective film is formed, side decomposition reaction by an electrolyte component other than the compound of the general formula (1) is suppressed, and particularly durability characteristics such as battery cycle and storage are improved. Presumed to be.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these embodiments, and can be arbitrarily modified and implemented.
1. Negative electrode The negative electrode used for the non-aqueous electrolyte secondary battery of the present invention is a negative electrode capable of occluding and releasing lithium ions, and includes a specific negative electrode active material. The negative electrode active material used for the negative electrode is described below.

<Negative electrode active material>
As the negative electrode active material is one of the components of the present invention, the Raman R value, defined as the ratio of the peak intensity of 1360 cm ^-1 to the peak intensity of 1580 cm ^-1 in the argon ion laser Raman spectroscopy is 0.1 or more It is only necessary to satisfy this condition, and there are no other restrictions. Here, the Raman R value in the present invention is 0.
One or more carbonaceous materials are defined below.
(Raman value)
The Raman R value of the negative electrode active material is a value measured using an argon ion laser Raman spectrum method, and is usually 0.01 or more, preferably 0.03 or more, more preferably 0.1 or more, and usually 1.5 or less, preferably 1.2 or less, more preferably 1 or less, particularly preferably 0.5 or less, and most preferably 0.35 or less.

  If the Raman R value is too small, the crystallinity of the particle surface becomes too high, and the number of sites where Li enters between layers decreases with charge and discharge, which may reduce charge acceptance. In addition, when the negative electrode is densified by applying it to the current collector and then pressing it, the crystals are likely to be oriented in a direction parallel to the electrode plate, which may lead to a decrease in load characteristics. In particular, when the Raman R value is 0.1 or more, a suitable film can be formed on the surface of the negative electrode, whereby storage characteristics, cycle characteristics, and load characteristics can be improved.

On the other hand, if the Raman R value is too large, the crystallinity of the particle surface is lowered, the reactivity with the non-aqueous electrolyte is increased, and the efficiency and gas generation may be increased.
Further, the Raman half-width in the vicinity of 1580 cm ^{−1 of} the negative electrode active material is not particularly limited, but is usually 10 cm ⁻¹ or more, preferably 15 cm ⁻¹ or more, and is usually 100 cm ⁻¹ or less, preferably 80 cm ⁻¹ or less. More preferably, it is 60 cm <^-1> or less, Most preferably, it is 40 cm <^-1> or less.

If the Raman half-value width is too small, the crystallinity of the particle surface becomes too high, and there is a tendency that the number of sites where Li enters between the layers increases with charge / discharge. That is, there is a tendency that charge acceptance is lowered. In addition, when the negative electrode is densified by applying it to the current collector and then pressing it, the crystals tend to be oriented in a direction parallel to the electrode plate, and the load characteristics tend to be reduced. On the other hand, if the Raman half width is too large, the crystallinity of the particle surface decreases, the reactivity with the non-aqueous electrolyte increases, and the efficiency tends to decrease and the gas generation increases.

The measurement of the Raman spectrum, using a Raman spectrometer (manufactured by JASCO Corporation Raman spectrometer), the sample is naturally dropped into the measurement cell and filled, and while irradiating the sample surface in the cell with argon ion laser light, This is done by rotating the cell in a plane perpendicular to the laser beam. The resulting Raman spectrum, the intensity _{I A} of the peak _{P A} in the vicinity of 1580 cm ^-1, and measuring the intensity _{I B} of a peak _{P B} in the vicinity of 1360 cm ^-1, the intensity ratio _{R (R = I B / I} A) Is calculated. The Raman R value calculated by the measurement is defined as the Raman R value of the negative electrode active material of the present invention. Further, the half width of the peak P _A in the vicinity of 1580 cm ^-1 of the resulting Raman spectrum was measured, which is defined as the Raman half-value width of the negative electrode active material of the present invention.

Moreover, said Raman measurement conditions are as follows.
Argon ion laser wavelength: 514.5nm
・ Laser power on the sample: 15-25mW
・ Resolution: 10-20cm ^-1
Measurement range: 1100 cm ^{−1 to} 1730 cm ⁻¹
-Raman R value, Raman half-width analysis: background treatment / smoothing treatment: simple average, 5 points of convolution Further, the negative electrode active material used in the present invention preferably has the following physical properties.

(D value)
The carbonaceous material defined in the present invention preferably has a d value (interlayer distance) of a lattice plane (002 plane) determined by X-ray diffraction by the Gakushin method, preferably 0.335 nm or more and less than 0.340 nm. That is. Here, the d value is more preferably 0.339 nm or less, and still more preferably 0.337 nm or less. If the d value is too large, the crystallinity may decrease and the initial irreversible capacity may increase. On the other hand, 0.335 nm is a theoretical value of graphite.

Examples of the carbonaceous material include natural carbonaceous materials and artificial carbonaceous materials. Preferably, the carbonaceous material includes at least one selected from the group consisting of a carbonaceous material obtained by coating carbon with nuclear graphite, a carbonaceous material obtained by coating graphite with nuclear graphite, and a natural carbonaceous material. Examples of the natural carbonaceous material include scaly graphite, scaly graphite, and soil graphite. Examples of the artificial carbonaceous material include graphite particles such as coke, needle coke, and high-density carbon material produced by heat-treating a pitch raw material. More preferred is a natural carbonaceous material spheroidized in terms of low cost and ease of electrode production.

(X-ray parameters)
The crystallite size (Lc) and (La) of the graphite particles determined by X-ray diffraction by the Gakushin method of the negative electrode active material is preferably 30 nm or more, and more preferably 100 nm or more. If the crystallite size is within this range, the amount of lithium that can be charged in the negative electrode active material is increased, and a high capacity is easily obtained, which is preferable.

(Volume-based average particle size)
The volume-based average particle diameter of the negative electrode active material is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, particularly preferably 7 μm, based on the volume-based average particle diameter (median diameter) determined by the laser diffraction / scattering method. In addition, it is usually 100 μm or less, preferably 50 μm or less, more preferably 40 μm or less, and particularly preferably 30 μm or less.

If the volume-based average particle size is too small, the irreversible capacity may increase, leading to loss of initial battery capacity. On the other hand, if the average particle size is too large, when an electrode is produced by coating, an uneven coating surface tends to be formed, which may be undesirable in the battery manufacturing process.
The volume-based average particle size is measured by dispersing carbon powder in a 0.2% by weight aqueous solution (about 10 mL) of polyoxyethylene (20) sorbitan monolaurate, which is a surfactant, and laser diffraction / scattering particle size distribution. This is carried out using a meter (LA-700 manufactured by Horiba, Ltd.). The median diameter determined by the measurement is defined as the volume-based average particle diameter of the negative electrode active material of the present invention.

(BET specific surface area)
The BET specific surface area of the negative electrode active material is a value of the specific surface area measured using the BET method, and is usually 0.1 m ² · g ⁻¹ or more, preferably 0.7 m ² · g ⁻¹ or more, more preferably 1 .0
m ² · g ⁻¹ or more, particularly preferably 1.5 m ² · g ⁻¹ or more, and usually 100
m ² · g ^-1 or less, preferably 25 m ² · g ^-1 or less, more preferably 15 m ² · g
⁻¹ or less, particularly preferably 10 m ² · g ⁻¹ or less.

  If the value of the BET specific surface area is too small, the acceptability of lithium is likely to deteriorate during charging when used as a negative electrode material, and lithium is likely to precipitate on the electrode surface, which may reduce the stability. On the other hand, if the value of the BET specific surface area is too large, the reactivity with the non-aqueous electrolyte increases when used as a negative electrode material, gas generation tends to increase, and a preferable battery tends to be difficult to obtain.

  The specific surface area was measured by the BET method using a surface area meter (a fully automated surface area measuring device manufactured by Okura Riken), preliminarily drying the sample at 350 ° C. for 15 minutes under nitrogen flow, Using a nitrogen helium mixed gas accurately adjusted so that the value of the relative pressure becomes 0.3, the nitrogen adsorption BET one-point method by the gas flow method is used. The specific surface area determined by the measurement is defined as the BET specific surface area of the negative electrode active material of the present invention.

(Tap density)
The tap density of the negative electrode active material is usually 0.1 g · cm ⁻³ or more, preferably 0.5 g · cm ⁻³ or more, more preferably 0.7 g · cm ⁻³ or more, particularly preferably 1 g · cm ⁻³ or more. Moreover, it is 2 g * cm <^-3> or less normally, Preferably it is 1.8 g * cm < ^-3 > or less, More preferably, it is 1.6 g * cm <^-3> or less. If the tap density is too small, when used as a negative electrode, the packing density is difficult to increase, and there is a tendency that a high-capacity battery cannot be obtained. On the other hand, if the tap density is too high, there are too few voids between the particles in the electrode, and it is difficult to ensure conductivity between the particles, and it is difficult to obtain preferable battery characteristics.

The tap density is measured by passing through a sieve having an opening of 300 μm, dropping the sample onto a 20 cm ³ tapping cell and filling the sample to the upper end surface of the cell, and then measuring a powder density measuring device (for example, manufactured by Seishin Enterprise Co., Ltd.). Using a tap denser, tapping with a stroke length of 10 mm is performed 1000 times, and the tap density is calculated from the volume at that time and the mass of the sample. The tap density calculated by the measurement is defined as the tap density of the negative electrode active material of the present invention.

(Orientation ratio)
The orientation ratio of the negative electrode active material is usually 0.005 or more, preferably 0.01 or more, more preferably 0.015 or more, and usually 0.67 or less. When the orientation ratio is too small, the high-density charge / discharge characteristics tend to decrease. The upper limit of the above range is the theoretical upper limit value of the orientation ratio of the carbonaceous material.

The orientation ratio is measured by X-ray diffraction after pressure-molding the sample. Set the molding obtained by filling 0.47 g of the sample into a molding machine with a diameter of 17 mm and compressing it with 58.8 MN · m ^{-2 so} that it is flush with the surface of the sample holder for measurement. X-ray diffraction is measured. From the (110) diffraction and (004) diffraction peak intensities of the obtained carbon, a ratio represented by (110) diffraction peak intensity / (004) diffraction peak intensity is calculated. The orientation ratio calculated by the measurement is defined as the orientation ratio of the negative electrode active material of the present invention.

The X-ray diffraction measurement conditions are as follows. “2θ” indicates a diffraction angle.
・ Target: Cu (Kα ray) graphite monochromator ・ Slit:
Divergence slit = 0.5 degree Light receiving slit = 0.15 mm
Scattering slit = 0.5 degree / measurement range and step angle / measurement time:
(110) face: 75 degrees ≦ 2θ ≦ 80 degrees 1 degree / 60 seconds (004) face: 52 degrees ≦ 2θ ≦ 57 degrees 1 degree / 60 seconds (Aspect ratio)
The aspect ratio (major axis / minor axis) of the graphite particles of the negative electrode active material is usually 0.05 or more, preferably 0.07 or more, more preferably 0.1 or more, particularly preferably 0.14 or more, and usually 20 The range is preferably 15 or less, more preferably 10 or less, and particularly preferably 7 or less.

If the aspect ratio is too small or too large, the particle shape becomes flat or needle-like, so it tends to be oriented parallel to the current collector in the electrode, and expansion due to Li insertion is in one direction. Tends to occur and the cycle characteristics tend to deteriorate.
On the other hand, if the aspect ratio is in the above range, when the electrode density is increased to increase the capacity, the graphite particles have a shape close to a sphere or a cube, and the graphite particles are less likely to be crushed and peel from the current collector. It is preferable because the cycle characteristics are improved.

Furthermore, it is preferable because the voids between graphite particles are likely to be large, Li diffusion between particles is accelerated, and improvement in rate characteristics can be expected. Furthermore, since the graphite particles are not easily crushed, the graphite particles are less likely to be oriented in the negative electrode, the expansion of the electrode accompanying charge / discharge can be suppressed, and the conductive path between the active materials is maintained, so that the cycle characteristics are improved.
In addition, since the expansion of the electrode can be suppressed, it is easy to secure the space inside the battery, and even if a small amount of gas is generated due to oxidative decomposition, there is a space inside the battery, so there is little increase in internal pressure, and it is difficult for the battery to expand. preferable.

The aspect ratio of the spheroidized graphite particles can be measured using the negative electrode according to the following procedure.
Take a photo of the negative electrode surface (or polish or cut it in a plane parallel to the film surface of the current collector and take a cross-sectional photograph thereof), and analyze the photographed image to determine the surface of the graphite particles (cross-section). ) Is measured at 50 points or more. In addition, the negative electrode was cut and polished perpendicularly to the film surface of the current collector, a cross-sectional photograph thereof was taken, and image analysis of the photographed photograph revealed that the short diameter (particle thickness) of the graphite particle cross section was 50 points. Measure above. An average value is obtained for each of the measured major axis and minor axis, and the ratio of the average major axis to the average minor axis is defined as an aspect ratio (major axis / minor axis).

In addition, when the negative electrode active material does not maintain the negative electrode form (for example, in powder form), the negative electrode active material particles are embedded in a resin in a state where they are arranged on a flat plate serving as a substrate such as glass, and the surface is parallel to the flat plate. Polish and cut and measure the major axis from the cross-sectional photograph as described above. Similarly, the minor axis of the graphite particle cross section can be measured to determine the aspect ratio.
Here, since the plate-like particles usually tend to be arranged so that the thickness direction of the particles is perpendicular to the flat plate, the above-mentioned method obtains characteristic long and short diameters of the particles. I can do it.

In addition, the cross-sectional (or surface) photograph of the particle is generally a scanning electron microscope (Scanning).
Photograph using Electron Microscope (SEM). However, when the shape of the spheroidized graphite cannot be specified by the SEM photograph, by taking a cross-sectional (surface) photograph in the same manner as described above using a polarizing microscope or a transmission electron microscope (TEM), The aspect ratio can be obtained.

  The method for obtaining the spheroidized graphite particles having an aspect ratio in the above range is not particularly limited. For example, the graphite particles are repeatedly subjected to mechanical action such as compression, friction, shearing force including the interaction of particles mainly with impact force. It is preferable to use an apparatus given in the above. Specifically, it has a rotor with a large number of blades installed inside the casing, and when the rotor rotates at high speed, mechanical action such as impact compression, friction, shearing force, etc. is applied to the carbon material introduced inside. It is preferable to use an apparatus that performs surface treatment. Moreover, it is preferable to have a mechanism that repeatedly gives a mechanical action by circulating a carbon material, or a mechanism that does not have a circulation mechanism but connects a plurality of apparatuses. As an example of a preferable apparatus, there can be mentioned a hybridization system manufactured by Nara Machinery Co., Ltd.

<Configuration and production method of negative electrode>
Any known method can be used for producing the electrode as long as the effects of the present invention are not significantly impaired. For example, it is formed by adding a binder, a solvent, and, if necessary, a thickener, a conductive material, a filler, etc. to a negative electrode active material to form a slurry, which is applied to a current collector described later, dried, and then pressed. can do.

(Current collector)
As the current collector for holding the negative electrode active material, a known material can be arbitrarily used. Examples of the current collector for the negative electrode include metal materials such as aluminum, copper, nickel, stainless steel, and nickel-plated steel. Copper is particularly preferable from the viewpoint of ease of processing and cost.
In addition, the shape of the current collector may be, for example, a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, an expanded metal, a punch metal, a foam metal, or the like when the current collector is a metal material. Among these, a metal thin film is preferable, a copper foil is more preferable, and a rolled copper foil by a rolling method and an electrolytic copper foil by an electrolytic method are more preferable.

The thickness of the current collector is usually 1 μm or more, preferably 5 μm or more, and is usually 100 μm or less, preferably 50 μm or less. This is because if the thickness of the negative electrode current collector is too thick, the capacity of the entire battery may be too low, and conversely if it is too thin, handling may be difficult.
(Thickness ratio between current collector and negative electrode active material layer)
The ratio of the thickness of the current collector to the negative electrode active material layer is not particularly limited, but the value of “(the thickness of the negative electrode active material layer on one side immediately before the nonaqueous electrolyte injection) / (thickness of the current collector)” However, 150 or less is preferable, 20 or less is more preferable, 10 or less is particularly preferable, 0.1 or more is preferable, 0.4 or more is more preferable, and 1 or more is particularly preferable. If the ratio of the thickness of the current collector to the negative electrode active material layer is too large, the current collector tends to generate heat due to Joule heat during high current density charge / discharge. On the other hand, if the ratio of the thickness of the current collector to the negative electrode active material layer is too small, the volume ratio of the current collector to the negative electrode active material increases, and the battery capacity tends to decrease.

(Binder)
The binder for binding the negative electrode active material is not particularly limited as long as it is a material that is stable with respect to the non-aqueous electrolyte solution and the solvent used in manufacturing the electrode.
Specific examples include resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, polyimide, cellulose, and nitrocellulose; SBR (styrene-butadiene rubber), isoprene rubber, butadiene rubber, fluorine rubber, Rubber polymers such as NBR (acrylonitrile / butadiene rubber) and ethylene / propylene rubber; styrene / butadiene / styrene block copolymer or hydrogenated product thereof; EPDM (ethylene / propylene / diene terpolymer), styrene / Thermoplastic elastomeric polymers such as ethylene / butadiene / styrene copolymers, styrene / isoprene / styrene block copolymers or hydrogenated products thereof; syndiotactic-1,2-polybutadiene, polyvinyl acetate , Soft resinous polymers such as ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer; polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymer, etc. And a polymer composition having ion conductivity of alkali metal ions (particularly lithium ions). These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.

  The ratio of the binder to the negative electrode active material is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, particularly preferably 0.6% by mass or more, and preferably 20% by mass or less, 15% by mass. The following is more preferable, 10% by mass or less is further preferable, and 8% by mass or less is particularly preferable. When the ratio of the binder to the negative electrode active material is too large, the binder ratio in which the binder amount does not contribute to the battery capacity increases, and the battery capacity tends to decrease. Moreover, when the ratio of a binder is too small, there exists a tendency which causes the strength reduction of a negative electrode.

  In particular, when a rubbery polymer typified by SBR is contained as a main component, the ratio of the binder to the negative electrode active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, and 0 .6% by mass or more is more preferable, and is usually 5% by mass or less, preferably 3% by mass or less, and more preferably 2% by mass or less. When the main component contains a fluorine-based polymer typified by polyvinylidene fluoride, the ratio to the negative electrode active material is usually 1% by mass or more, preferably 2% by mass or more, and more preferably 3% by mass or more. It is preferably 15% by mass or less, preferably 10% by mass or less, and more preferably 8% by mass or less.

(Slurry forming solvent)
The solvent for forming the slurry is not particularly limited as long as it is a solvent capable of dissolving or dispersing the negative electrode active material, the binder, and the thickener and conductive material used as necessary. Alternatively, either an aqueous solvent or an organic solvent may be used.
Examples of the aqueous solvent include water and alcohol. Examples of the organic solvent include N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N, N- Examples include dimethylaminopropylamine, tetrahydrofuran (THF), toluene, acetone, diethyl ether, dimethylacetamide, hexamethylphosphalamide, dimethyl sulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene, hexane, and the like.

In particular, when an aqueous solvent is used, it is preferable to add a dispersant or the like in addition to the thickener and slurry it using a latex such as SBR. In addition, these solvents may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and a ratio.
(Thickener)
A thickener is normally used in order to adjust the viscosity of the slurry at the time of producing a negative electrode active material layer. The thickener is not particularly limited, and specific examples include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.

  Further, when using a thickener, the ratio of the thickener to the negative electrode active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 0.6% by mass or more, Moreover, it is 5 mass% or less normally, 3 mass% or less is preferable, and 2 mass% or less is more preferable. When the ratio of the thickener to the negative electrode active material is too small, applicability tends to be remarkably lowered. Moreover, when there are too many ratios of a thickener, the ratio of the negative electrode active material which occupies for a negative electrode active material layer will fall, and there exists a tendency for the capacity | capacitance of a battery to fall and the resistance between negative electrode active materials to increase.

(Electrode density)
The electrode structure when the negative electrode active material is made into an electrode is not particularly limited, but the density of the negative electrode active material present on the current collector is preferably 1 g · cm ⁻³ or more, and 1.2 g · cm ⁻³ or more. but more preferably, particularly preferably 1.3 g · ^{cm -3} or more, preferably 2.2 g · ^{cm -3} or less, more preferably 2.1 g · ^{cm -3} or less, 2.0 g · ^{cm -3} or less Further preferred is 1.9 g · cm ⁻³ or less. If the density of the negative electrode active material present on the current collector is too large, the negative electrode active material particles will be destroyed, increasing the initial irreversible capacity, and the non-aqueous electrolyte solution near the current collector / negative electrode active material interface. There is a tendency for high current density charge / discharge characteristics to deteriorate due to a decrease in permeability. On the other hand, if the density is too small, the conductivity between the negative electrode active materials decreases, the battery resistance increases, and the capacity per unit volume tends to decrease.

(Thickness of negative electrode plate)
The thickness of the negative electrode plate is designed according to the positive electrode plate used, and is not particularly limited, but the thickness of the negative electrode active material layer obtained by subtracting the metal foil (current collector) thickness from the negative electrode plate is usually 15 μm.
Above, preferably 20 μm or more, more preferably 30 μm or more, and usually 300 μm or less, preferably 280 μm or less, more preferably 250 μm or less.

(Surface coating of negative electrode plate)
Moreover, you may use what adhered the substance of the composition different from this to the surface of the said negative electrode plate. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate and carbonates such as lithium carbonate, calcium carbonate and magnesium carbonate.

2. Non-aqueous electrolyte 2-1. Electrolyte <Lithium salt>
As the electrolyte, a lithium salt is usually used. The lithium salt is not particularly limited as long as it is known to be used for this purpose, and any lithium salt can be used. Specific examples include the following.

For _{example, LiPF 6, LiBF 4, LiClO} 4, LiAlF 4, LiSbF 6, inorganic lithium salts LiTaF 6, LiWF ₇ and the like;
Lithium tungstates such as LiWOF ₅ ;
HCO ₂ Li, CH ₃ CO ₂ Li, CH ₂ FCO ₂ Li, CHF ₂ CO ₂ Li, CF ₃ CO ₂ Li, CF ₃ CH ₂ CO ₂ Li, CF ₃ CF ₂ CO ₂ Li, CF ₃ CF ₂ CF ₂ Carboxylic acid lithium salts such as CO ₂ Li, CF ₃ CF ₂ CF ₂ CF ₂ CO ₂ Li;
CH ₃ SO ₃ Li, CH ₂ FSO ₃ Li, CHF ₂ SO ₃ Li, CF ₃
Sulfonic acid lithium salts such as SO ₃ Li, CF ₃ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ CF ₂ SO ₃ Li;
LiN (FCO) ₂ , LiN (FCO) (FSO ₂ ), LiN (FSO ₂ ) ₂ , LiN (
FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-par Lithium imide salts such as fluoropropanedisulfonylimide, LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ );
Lithium metide salts such as LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ ;
In addition, LiPF ₄ (CF ₃ ) ₂ , LiPF ₄ (C ₂ F ₅ ) ₂ , LiPF ₄ (CF ₃ SO
₂ ) ₂ , LiPF ₄ (C ₂ F ₅ SO ₂ ) ₂ , LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiBF ₃ C ₃ F ₇ , LiBF ₂ (CF ₃ ) ₂ , LiBF ₂ (C ₂ F ₅ ) ₂ , fluorine-containing organic lithium salts such as LiBF ₂ (CF ₃ SO ₂ ) ₂ and LiBF ₂ (C ₂ F ₅ SO ₂ ) ₂ ;

Among them, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiTaF ₆ , LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ , LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) _3, etc. are output characteristics, high rate charge / discharge characteristics, high temperature storage characteristics, cycle This is particularly preferable from the viewpoint of improving the characteristics and the like.

  The concentration of these lithium salts in the non-aqueous electrolyte and the lithium salts represented by (A) and (B) described later is not particularly limited as long as the effects of the present invention are not impaired. The total molar concentration of the lithium salt in the non-aqueous electrolyte is preferably 0.3 mol / L or more, more preferably 0.4 mol, from the viewpoint of ensuring the electric conductivity of the liquid in a good range and ensuring good battery performance. / L or more, more preferably 0.5 mol / L or more, preferably 3 mol / L or less, more preferably 2.5 mol / L or less, still more preferably 2.0 mol / L or less. If it is this range, effects, such as a low temperature characteristic, cycling characteristics, and a high temperature characteristic, will improve. On the other hand, if the total molar concentration of lithium is too low, the electrical conductivity of the electrolyte may be insufficient. On the other hand, if the concentration is too high, the electrical conductivity may decrease due to an increase in viscosity. May decrease.

2-2. Solvent As the non-aqueous solvent, a saturated cyclic carbonate, a cyclic carbonate having a fluorine atom, a chain carbonate, a cyclic and chain carboxylic acid ester, an ether compound, a sulfone compound, and the like can be used.
<Saturated cyclic carbonate>
Examples of the saturated cyclic carbonate include those having an alkylene group having 2 to 4 carbon atoms. Specifically, examples of the saturated cyclic carbonate having 2 to 4 carbon atoms include ethylene carbonate, propylene carbonate, and butylene carbonate. Among these, ethylene carbonate and propylene carbonate are particularly preferable from the viewpoint of improving battery characteristics resulting from an improvement in the degree of lithium ion dissociation.

A saturated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.
The blending amount of the saturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The lower limit of the blending amount when one kind is used alone is 5% in 100% by volume of the non-aqueous solvent. Volume% or more, more preferably 10 volume% or more. By setting this range, the decrease in electrical conductivity due to the decrease in the dielectric constant of the non-aqueous electrolyte is avoided, and the high current discharge characteristics, stability against the negative electrode, and cycle characteristics of the non-aqueous electrolyte battery are in a good range. And it will be easier. Moreover, an upper limit is 95 volume% or less, More preferably, it is 90 volume% or less, More preferably, it is 85 volume% or less. By setting it as this range, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, the decrease in ionic conductivity is suppressed, and the load characteristics of the non-aqueous electrolyte battery are easily set in a favorable range.

  Moreover, one of the preferable combinations in the case of using 2 or more types of saturated cyclic carbonates by arbitrary combinations is a combination of ethylene carbonate and propylene carbonate. In this case, the volume ratio of ethylene carbonate to propylene carbonate is preferably 99: 1 to 10:90, and particularly preferably 95: 5 to 10:60. Furthermore, the amount of propylene carbonate in the entire non-aqueous solvent is 0.1% by volume or more, preferably 1% by volume or more, more preferably 2% by volume or more, and the upper limit is usually 20% by volume or less, preferably 8% by volume. % Or less, more preferably 5% by volume or less. When propylene carbonate is contained within this range, it is preferable because the low temperature characteristics are further excellent while maintaining the combination characteristics of ethylene carbonate and dialkyl carbonates.

<Cyclic carbonate having a fluorine atom>
The cyclic carbonate having a fluorine atom (hereinafter also referred to as fluorinated cyclic carbonate) is not particularly limited as long as it is a cyclic carbonate having a fluorine atom.
Examples of the fluorinated cyclic carbonate include derivatives of cyclic carbonates having an alkylene group having 2 to 6 carbon atoms, such as ethylene carbonate derivatives. Examples of the ethylene carbonate derivative include fluorinated products of ethylene carbonate or ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms), and particularly those having 1 to 8 fluorine atoms. Is preferred.

  Specifically, monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4- Fluoro-5-methylethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4- (fluoromethyl) -ethylene carbonate, 4- (difluoromethyl) -ethylene carbonate, 4- (trifluoromethyl) -ethylene carbonate 4- (fluoromethyl) -4-fluoroethylene carbonate, 4- (fluoromethyl) -5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,5-difluoro-4,5-dimethyl Le ethylene carbonate, 4,4-difluoro-5,5-dimethylethylene carbonate.

Among them, at least one selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, and 4,5-difluoro-4,5-dimethylethylene carbonate has high ionic conductivity. It is more preferable in terms of imparting properties and suitably forming an interface protective film.
A fluorinated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios. The blending amount of the fluorinated cyclic carbonate is not particularly limited and may be arbitrary as long as the effects of the present invention are not significantly impaired, but in 100% by volume of the non-aqueous solvent, preferably 0.01% by volume or more, more preferably 0.8%. It is 1 volume% or more, More preferably, it is 0.2 volume% or more, Preferably it is 95 volume% or less, More preferably, it is 90 volume% or less. If it is this range, a non-aqueous electrolyte battery is easy to express sufficient cycle characteristic improvement effect, and it is easy to avoid that a discharge capacity maintenance factor falls by the fall of a high temperature storage characteristic or the increase in the amount of gas generation.

In addition, the cyclic carbonate having a fluorine atom has an effective function not only as a solvent but also as “(C) a carbonate having at least one carbon-carbon unsaturated bond or fluorine atom” described in 1-4-3 below. To express. There is no clear boundary in the blending amount when used as a cyclic carbonate solvent / auxiliary having a fluorine atom, and the blending amount described later can be followed as it is.

<Chain carbonate>
As a chain carbonate, a C3-C7 thing is preferable.
Specifically, as the chain carbonate having 3 to 7 carbon atoms, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, Examples include n-butyl methyl carbonate, isobutyl methyl carbonate, t-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butyl ethyl carbonate, isobutyl ethyl carbonate, t-butyl ethyl carbonate.

Among them, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, and methyl n-propyl carbonate are preferable, and dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate are particularly preferable. is there.
Further, chain carbonates having a fluorine atom (hereinafter also referred to as fluorinated chain carbonate) can be suitably used. The number of fluorine atoms contained in the fluorinated chain carbonate is not particularly limited as long as it is 1 or more, but is usually 6 or less, preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon or may be bonded to different carbons. Examples of the fluorinated chain carbonate include a fluorinated dimethyl carbonate derivative, a fluorinated ethyl methyl carbonate derivative, and a fluorinated diethyl carbonate derivative.

Examples of the fluorinated dimethyl carbonate derivative include fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, bis (difluoro) methyl carbonate, bis (trifluoromethyl) carbonate, and the like.
Fluorinated ethyl methyl carbonate derivatives include 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2-trimethyl Examples include fluoroethyl methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate, and ethyl trifluoromethyl carbonate.

  Fluorinated diethyl carbonate derivatives include ethyl- (2-fluoroethyl) carbonate, ethyl- (2,2-difluoroethyl) carbonate, bis (2-fluoroethyl) carbonate, ethyl- (2,2,2-trifluoro). Ethyl) carbonate, 2,2-difluoroethyl-2′-fluoroethyl carbonate, bis (2,2-difluoroethyl) carbonate, 2,2,2-trifluoroethyl-2′-fluoroethyl carbonate, 2,2, Examples include 2-trifluoroethyl-2 ′, 2′-difluoroethyl carbonate, bis (2,2,2-trifluoroethyl) carbonate, and the like.

A chain carbonate may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The amount of the chain carbonate is preferably 5% by volume or more, more preferably 10% by volume or more, and further preferably 15% by volume or more in 100% by volume of the non-aqueous solvent. By setting the lower limit in this way, the viscosity of the non-aqueous electrolyte solution is set in an appropriate range, the decrease in ionic conductivity is suppressed, and the large current discharge characteristics of the non-aqueous electrolyte battery are easily set in a favorable range. Also,
The chain carbonate is preferably 90% by volume or less, more preferably 85% by volume or less, in 100% by volume of the nonaqueous solvent. By setting the upper limit in this way, it is easy to avoid a decrease in electrical conductivity resulting from a decrease in dielectric constant of the nonaqueous electrolyte solution, and to make the large current discharge characteristics of the nonaqueous electrolyte solution battery in a favorable range.

Battery performance can be remarkably improved by combining cyclic carbonate and / or cyclic carbonate having a fluorine atom with a specific amount in combination with a specific chain carbonate.
For example, when dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate is selected as the specific chain carbonate, the blending amount of the cyclic carbonate and / or the cyclic carbonate having a fluorine atom is 10% by volume or more, preferably 15% by volume or more. 80 volume% or less, preferably 50 volume% or less, more preferably 35 volume% or less, and the amount of dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate is 20 volume% or more, preferably 50 volume% or more, and more preferably Is 65 volume% or more and 90 volume% or less, preferably 85 volume% or less. By selecting such a blending amount, the low-temperature deposition temperature of the electrolyte is lowered, the viscosity of the nonaqueous electrolytic solution is also lowered to improve the ionic conductivity, and a high output can be obtained even at a low temperature.

  It is also preferable to use two or more types of specific chain carbonates in combination. When dimethyl carbonate and ethyl methyl carbonate are used in combination with a specific chain carbonate, the amount of cyclic carbonate and / or cyclic carbonate having a fluorine atom is 10% by volume or more, preferably 15% by volume or more and 60% by volume or less. Particularly preferred are those in which the blending amount of dimethyl carbonate is 10% by volume or more and 70% by volume or less, and the blending amount of ethylmethyl carbonate is 10% by volume or more and 80% by volume or less. Further, when dimethyl carbonate and diethyl carbonate are used in combination with a specific chain carbonate, the blending amount of the cyclic carbonate and / or the cyclic carbonate having a fluorine atom is 10% by volume or more, preferably 15% by volume or more, 60% by volume. Hereinafter, it is particularly preferable that the amount of dimethyl carbonate is 10% by volume to 70% by volume and the amount of diethyl carbonate is 10% by volume to 70% by volume. Further, when ethyl methyl carbonate and diethyl carbonate are used in combination with the specific chain carbonate, the blending amount of the cyclic carbonate and / or the cyclic carbonate having a fluorine atom is 10% by volume or more, preferably 15% by volume or more, 60% by volume. % Or less, the amount of ethyl methyl carbonate is 10% by volume or more and 80% by volume or less, and the amount of diethyl carbonate is 10% by volume or more and 70% by volume or less is particularly preferable.

Examples of the cyclic carbonate and / or cyclic carbonate having a fluorine atom include ethylene carbonate, monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, and 4,5-difluoro-4,5. -Dimethyl ethylene carbonate is preferred.
<Cyclic carboxylic acid ester>
Examples of the cyclic carboxylic acid ester include those having 3 to 12 total carbon atoms in the structural formula. Specific examples include gamma butyrolactone, gamma valerolactone, gamma caprolactone, epsilon caprolactone, and the like. Among these, gamma butyrolactone is particularly preferable from the viewpoint of improving battery characteristics resulting from an improvement in the degree of lithium ion dissociation.

The amount of the cyclic carboxylic acid ester is usually 5% by volume or more, more preferably 10% by volume or more, in 100% by volume of the non-aqueous solvent. By setting the lower limit in this way, the electrical conductivity of the non-aqueous electrolyte solution is improved and the large current discharge characteristics of the non-aqueous electrolyte battery are easily improved. Moreover, the compounding quantity of cyclic carboxylic acid ester becomes like this. Preferably it is 50 volume% or less, More preferably, it is 40 volume% or less. By setting the upper limit in this way, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, a decrease in electrical conductivity is avoided, an increase in negative electrode resistance is suppressed, and a large current discharge of the non-aqueous electrolyte secondary battery is performed. It becomes easy to make a characteristic into a favorable range.

<Chain carboxylic acid ester>
Examples of the chain carboxylic acid ester include those having 3 to 7 carbon atoms in the structural formula. Specifically, methyl acetate, ethyl acetate, acetic acid-n-propyl, isopropyl acetate, acetic acid-n-butyl, isobutyl acetate, acetic acid-t-butyl, methyl propionate, ethyl propionate, propionate-n-propyl, Isopropyl propionate, n-butyl propionate, isobutyl propionate, t-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, methyl isobutyrate, ethyl isobutyrate, isobutyric acid-n- Examples include propyl and isopropyl isobutyrate.

Among them, methyl acetate, ethyl acetate, acetate-n-propyl acetate-n-butyl acetate, methyl propionate, ethyl propionate, propionate-n-propyl, isopropyl propionate, methyl butyrate, ethyl butyrate, etc. It is preferable from the viewpoint of improvement of ionic conductivity.
The compounding amount of the chain carboxylic acid ester is usually 10% by volume or more, more preferably 15% by volume or more, in 100% by volume of the non-aqueous solvent. By setting the lower limit in this way, the electrical conductivity of the non-aqueous electrolyte solution is improved, and the large current discharge characteristics of the non-aqueous electrolyte battery are easily improved. Moreover, the compounding quantity of chain | strand-shaped carboxylic acid ester is 60 volume% or less preferably in 100 volume% of nonaqueous solvents, More preferably, it is 50 volume% or less. By setting the upper limit in this way, an increase in negative electrode resistance is suppressed, and the large current discharge characteristics and cycle characteristics of the non-aqueous electrolyte battery are easily set in a favorable range.

<Ether compound>
As the ether compound, a chain ether having 3 to 10 carbon atoms in which part of hydrogen may be substituted with fluorine, and a cyclic ether having 3 to 6 carbon atoms are preferable.
Examples of the chain ether having 3 to 10 carbon atoms include diethyl ether, di (2-fluoroethyl) ether, di (2,2-difluoroethyl) ether, di (2,2,2-trifluoroethyl) ether, ethyl (2-fluoroethyl) ether, ethyl (2,2,2-trifluoroethyl) ether, ethyl (1,1,2,2-tetrafluoroethyl) ether, (2-fluoroethyl) (2,2,2 -Trifluoroethyl) ether, (2-fluoroethyl) (1,1,2,2-tetrafluoroethyl) ether, (2,2,2-trifluoroethyl) (1,1,2,2-tetrafluoro) Ethyl) ether, ethyl-n-propyl ether, ethyl (3-fluoro-n-propyl) ether, ethyl (3,3,3-trifluoro-n-propyl) Ether, ethyl (2,2,3,3-tetrafluoro-n-propyl) ether, ethyl (2,2,3,3,3-pentafluoro-n-propyl) ether, 2-fluoroethyl-n-propyl Ether, (2-fluoroethyl) (3-fluoro-n-propyl) ether, (2-fluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (2-fluoroethyl) (2, 2,3,3-tetrafluoro-n-propyl) ether, (2-fluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, 2,2,2-trifluoroethyl -N-propyl ether, (2,2,2-trifluoroethyl) (3-fluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (3,3,3-trifluoro Olo-n-propyl) ether, (2,2,2-trifluoroethyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (2 , 2,3,3,3-pentafluoro-n-propyl) ether, 1,1,2,2-tetrafluoroethyl-n-propyl ether, (1,1,2,2-tetrafluoroethyl) (3 -Fluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) ) (2,2,3,3-tetrafluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) Ether, di-n-propyl Ether, (n-propyl) (3-fluoro-n-propyl) ether, (n-propyl) (3,3,3-trifluoro-n-propyl) ether, (n-propyl) (2,2,3 , 3-tetrafluoro-n-propyl) ether, (n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3-fluoro-n-propyl) ether, ( 3-Fluoro-n-propyl) (3,3,3-trifluoro-n-propyl) ether, (3-fluoro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether , (3-fluoro-n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3,3,3-trifluoro-n-propyl) ether, (3 3,3-triflu (Ro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (3,3,3-trifluoro-n-propyl) (2,2,3,3,3-penta Fluoro-n-propyl) ether, di (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,3,3-tetrafluoro-n-propyl) (2,2,3 3,3-pentafluoro-n-propyl) ether, di (2,2,3,3,3-pentafluoro-n-propyl) ether, di-n-butyl ether, dimethoxymethane, methoxyethoxymethane, methoxy (2 -Fluoroethoxy) methane, methoxy (2,2,2-trifluoroethoxy) methanemethoxy (1,1,2,2-tetrafluoroethoxy) methane, diethoxymethane, ethoxy (2-fur Roethoxy) methane, ethoxy (2,2,2-trifluoroethoxy) methane, ethoxy (1,1,2,2-tetrafluoroethoxy) methane, di (2-fluoroethoxy) methane, (2-fluoroethoxy) ( 2,2,2-trifluoroethoxy) methane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) methanedi (2,2,2-trifluoroethoxy) methane, (2,2, 2-trifluoroethoxy) (1,1,2,2-tetrafluoroethoxy) methane, di (1,1,2,2-tetrafluoroethoxy) methane, dimethoxyethane, methoxyethoxyethane, methoxy (2-fluoroethoxy) ) Ethane, methoxy (2,2,2-trifluoroethoxy) ethane, methoxy (1,1,2,2-tetrafluoroeth) Xyl) ethane, diethoxyethane, ethoxy (2-fluoroethoxy) ethane, ethoxy (2,2,2-trifluoroethoxy) ethane, ethoxy (1,1,2,2-tetrafluoroethoxy) ethane, di (2 -Fluoroethoxy) ethane, (2-fluoroethoxy) (2,2,2-trifluoroethoxy) ethane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (2, 2,2-trifluoroethoxy) ethane, (2,2,2-trifluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (1,1,2,2-tetrafluoroethoxy) Ethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether, etc. And the like.

Examples of the cyclic ether having 3 to 6 carbon atoms include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1 , 4-dioxane and the like, and fluorinated compounds thereof.
Among them, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether have high solvating ability to lithium ions and improve ion dissociation. Of these, dimethoxymethane, diethoxymethane, and ethoxymethoxymethane are preferable because they have low viscosity and give high ionic conductivity.

The compounding amount of the ether compound is usually in 100% by volume of the non-aqueous solvent, preferably 5% by volume or more, more preferably 10% by volume or more, further preferably 15% by volume or more, and preferably 70% by volume or less. More preferably, it is 60 volume% or less, More preferably, it is 50 volume% or less. If it is this range, it is easy to ensure the improvement effect of the lithium ion dissociation degree of chain ether, and the improvement of the ionic conductivity derived from a viscosity fall, and when a negative electrode active material is a carbonaceous material, a chain ether with lithium ion It is easy to avoid a situation where the capacity is reduced due to co-insertion.

<Sulfone compound>
As the sulfone compound, a cyclic sulfone having 3 to 6 carbon atoms and a chain sulfone having 2 to 6 carbon atoms are preferable. The number of sulfonyl groups in one molecule is preferably 1 or 2.
Examples of the cyclic sulfone include trimethylene sulfones, tetramethylene sulfones, and hexamethylene sulfones that are monosulfone compounds; trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones that are disulfone compounds. Among these, from the viewpoint of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable.

As sulfolanes, sulfolane and / or sulfolane derivatives (hereinafter also referred to as sulfolanes including sulfolane) are preferable. As the sulfolane derivative, one in which one or more hydrogen atoms bonded to the carbon atom constituting the sulfolane ring are substituted with a fluorine atom or an alkyl group is preferable.
Among them, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,2-difluorosulfolane, 2,3-difluorosulfolane, 2,4-difluorosulfolane, 2,5-difluorosulfolane, 3,4-difluorosulfolane, 2-fluoro-3-methylsulfolane, 2-fluoro-2-methylsulfolane, 3-fluoro-3-methylsulfolane, 3-fluoro-2-methylsulfolane, 4-fluoro-3-methyl Sulfolane, 4-fluoro-2-methylsulfolane, 5-fluoro-3-methylsulfolane, 5-fluoro-2-methylsulfolane, 2-fluoromethylsulfolane, 3-fluoromethylsulfolane, 2-difluoromethylsulfolane, 3-difluoro Methyl sulfolane, 2- Trifluoromethylsulfolane, 3-trifluoromethylsulfolane, 2-fluoro-3- (trifluoromethyl) sulfolane, 3-fluoro-3- (trifluoromethyl) sulfolane, 4-fluoro-3- (trifluoromethyl) sulfolane , 5-fluoro-3- (trifluoromethyl) sulfolane and the like are preferable in terms of high ionic conductivity and high input / output.

  As the chain sulfone, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, n-propyl ethyl sulfone, di-n-propyl sulfone, isopropyl methyl sulfone, isopropyl ethyl sulfone, diisopropyl sulfone, n- Butyl methyl sulfone, n-butyl ethyl sulfone, t-butyl methyl sulfone, t-butyl ethyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, Trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trif Oromethylsulfone, perfluoroethylmethylsulfone, ethyltrifluoroethylsulfone, ethylpentafluoroethylsulfone, di (trifluoroethyl) sulfone, perfluorodiethylsulfone, fluoromethyl-n-propylsulfone, difluoromethyl-n-propylsulfone Trifluoromethyl-n-propylsulfone, fluoromethylisopropylsulfone, difluoromethylisopropylsulfone, trifluoromethylisopropylsulfone, trifluoroethyl-n-propylsulfone, trifluoroethylisopropylsulfone, pentafluoroethyl-n-propylsulfone, Pentafluoroethyl isopropyl sulfone, trifluoroethyl-n-butyl sulfone, trifluoroethyl-t-butyl sulfone Emissions, pentafluoroethyl -n- butyl sulfone, pentafluoroethyl -t- butyl sulfone, and the like.

  Among them, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, isopropyl methyl sulfone, n-butyl methyl sulfone, t-butyl methyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone , Monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoro Ethyl sulfone, trifluoromethyl-n-propyl sulfone, trifluoromethyl isopropyl sulfone, tri Ruoroechiru -n- butyl sulfone, trifluoroethyl -t- butyl sulfone, trifluoromethyl -n- butyl sulfone, trifluoromethyl -t- butyl sulfone is preferred because a higher high output ionic conductivity.

  The amount of the sulfone compound is usually 5% by volume or more, more preferably 10% by volume or more, still more preferably 15% by volume or more in 100% by volume of the non-aqueous solvent, and preferably 40% by volume. Hereinafter, it is more preferably 35% by volume or less, still more preferably 30% by volume or less. Within this range, durability improvement effects such as cycle characteristics and storage characteristics can be easily obtained, and the viscosity of the non-aqueous electrolyte can be set to an appropriate range to avoid a decrease in electrical conductivity. When charging / discharging an aqueous electrolyte battery at a high current density, it is easy to avoid a situation in which the charge / discharge capacity retention rate decreases.

2-3. The present invention relates to a non-aqueous electrolyte solution containing a lithium salt and a non-aqueous solvent that dissolves the lithium salt, a negative electrode capable of occluding and releasing lithium ions, and a non-electrode provided with a positive electrode. An aqueous electrolyte secondary battery is characterized in that the nonaqueous electrolyte contains at least one or more compounds selected from the group consisting of compounds represented by the following general formula (1).

In the above formula, X and Z are CR ¹ ₂ , C═O, C═N—R ¹ , C═P—R ¹ , O, S, N—
R ¹ and P—R ¹ are represented and may be the same or different. Y represents CR ¹ ₂ , C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ³ . In the formula, R and R ¹ are hydrogen, halogen, or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same or different. R ² is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group. R ³ is Li, NR ⁴ ₄ or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group. R ⁴ is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same or different. n and m represent an integer of 0 or more. W is a range having the same meaning as R, and W may be the same as or different from R.

<Compound represented by the general formula (1)>
In the formula, X and Z are not particularly limited as long as they are in the range described in the general formula (1), but CR ¹ ₂ ,
O, S, and N—R ¹ are more preferable. Y is not particularly limited as long as it is within the range described in the general formula (1), but C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O). -OR
³ is more preferable. R and R ¹ are not particularly limited as long as they are within the range described in the general formula (1), but preferably have hydrogen, fluorine, a saturated aliphatic hydrocarbon group which may have a substituent, or a substituent. Examples thereof may include an unsaturated aliphatic hydrocarbon group which may be substituted, and an aromatic hydrocarbon group which may have a substituent.

R ² and R ⁴ are not particularly limited as long as they are within the range described in the general formula (1), but are preferably a saturated aliphatic hydrocarbon group that may have a substituent or a substituent. Examples thereof include unsaturated aliphatic hydrocarbons and optionally substituted aromatic hydrocarbons / aromatic heterocycles.
R ³ is not particularly limited as long as it is within the range described in the general formula (1), but preferably Li, a saturated aliphatic hydrocarbon which may have a substituent, or an unsaturated which may have a substituent Examples thereof include an aliphatic hydrocarbon and an aromatic hydrocarbon / aromatic heterocycle which may have a substituent.

  Substituents of saturated aliphatic hydrocarbons which may have substituents, unsaturated aliphatic hydrocarbons which may have substituents, aromatic hydrocarbons and aromatic heterocycles which may have substituents Is not particularly limited, but preferably has a saturated aliphatic hydrocarbon group, which may have a substituent such as halogen, carboxylic acid, carbonic acid, sulfonic acid, phosphoric acid, phosphorous acid, etc. And an unsaturated aliphatic hydrocarbon group which may be substituted, an ester of an aromatic hydrocarbon group which may have a substituent, and the like, more preferably halogen, and most preferably fluorine.

  Preferable saturated aliphatic hydrocarbons include, specifically, methyl group, ethyl group, fluoromethyl group, difluoromethyl group, trifluoromethyl group, 1-fluoroethyl group, 2-fluoroethyl group, 1,1-difluoroethyl. Group, 1,2-difluoroethyl group, 2,2-difluoroethyl group, 1,1,2-trifluoroethyl group, 1,2,2-trifluoroethyl group, 2,2,2-trifluoroethyl group Examples thereof include a phenyl group, a cyclopentyl group, and a cyclohexyl group.

Specific preferred unsaturated aliphatic hydrocarbons include ethenyl, 1-fluoroethenyl, 2-fluoroethenyl, 1-methylethenyl, 2-propenyl, and 2-fluoro-2-propenyl. , 3-fluoro-2-propenyl group, ethynyl group, 2-fluoroethynyl group, 2-propynyl group, and 3-fluoro-2propynyl group.
Preferred aromatic hydrocarbons include phenyl group, 2-fluorophenyl group, 3-fluorophenyl group, 2,4-difluorophenyl group, 2,6-difluorophenyl group, 3,5-difluorophenyl group, 2, 4 , 6-trifluorophenyl group.

Preferred aromatic heterocycles include 2-furanyl group, 3-furanyl group, 2-thiophenyl group, 3-thiophenyl group, 1-methyl-2-pyrrolyl group, and 1-methyl-3-pyrrolyl group.
Among these, a methyl group, an ethyl group, a fluoromethyl group, a trifluoromethyl group, a 2-fluoroethyl group, a 2,2,2-trifluoroethyl group, an ethenyl group, an ethynyl group, and a phenyl group are more preferable.

More preferred are a methyl group, an ethyl group, and an ethynyl group.
n and m are not particularly limited as long as they are within the range described in the general formula (1), but are preferably 0 or 1, and more preferably n = m = 1 or n = 1 and m = 0. The molecular weight is preferably 50 or more. Moreover, Preferably it is 500 or less. If it is this range, it will be easy to ensure the solubility of the unsaturated cyclic carbonate with respect to a non-aqueous electrolyte solution, and the effect of this invention will fully be expressed easily. Specific examples of these preferable compounds are shown below.

Among these, it is preferable that R is hydrogen, a fluorine, or an ethynyl group from both the reactivity and the stability. In the case of other substituents, the reactivity is lowered, and the expected properties may be lowered. Moreover, when it is halogen other than fluorine, there is a possibility that the reactivity is too high and the side reaction increases.
The number of fluorine or ethynyl groups in R is preferably within 2 in total. If the number is too large, the compatibility with the electrolytic solution may be deteriorated, and the reactivity may be too high to increase the side reaction.

Among these, n = 1 and m = 0 are preferable. When both are 0, stability deteriorates from the distortion of the ring, the reactivity becomes too high, and there is a possibility that side reactions increase. Further, even if n = 2 or more, or n = 1, when m = 1 or more, there is a possibility that the chain is more stable than the ring and the initial characteristics may not be exhibited.
Furthermore, wherein, X and Z are, ^CR _{1 2} or O are more preferred. In cases other than these, the reactivity may be too high and side reactions may increase.

The molecular weight is more preferably 100 or more, and more preferably 200 or less. If it is this range, it will be easy to ensure further the solubility of General formula (1) with respect to a non-aqueous electrolyte solution, and the effect of this invention will be further fully expressed easily.
Among these, specific examples of more preferable compounds are shown below.

More preferably, R is all hydrogen. In this case, the side reaction is most likely to be suppressed while maintaining the expected characteristics. In addition, when Y is C═O or S═O, one of X and Z is O, indicating that Y is S (═O) ₂ , P (═O) —R ² , P
In the case of (═O) —OR ³ , it is preferable that both X and Z are O or CH ₂ , or one of X and Z is O and the other is CH ₂ . When Y is C═O or S═O, if both X and Z are CH ₂ , the reactivity may be too high and side reactions may increase.

  Specific examples of these compounds are shown below.

  Of the compounds represented by the general formula (1), the compound represented by the general formula (2) is preferable from the viewpoint of ease of industrial production.

In the above formula (2), Y is C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O).
It represents the -OR ^3. R ² is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group. R ³ is Li, NR ⁴ ₄ or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group. R ⁴ is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same or different.

  Specific examples of these compounds having preferable conditions are shown below.

The compound represented by General formula (1) may be used individually by 1 type, or may have 2 or more types by arbitrary combinations and ratios. Moreover, the compounding quantity of the compound represented by General formula (1) is not restrict | limited especially, unless the effect of this invention is impaired remarkably. The compounding amount of the compound represented by the general formula (1) is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and further preferably 0.1% by mass in 100% by mass of the non-aqueous electrolyte solution. % Or more, preferably 5% by mass or less, more preferably 4% by mass or less, and still more preferably 3% by mass or less. If it is in this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristic improvement effect, and the high-temperature storage characteristic is reduced, and the discharge capacity maintenance rate is reduced by increasing the amount of gas generated. It is easy to avoid such a situation. On the other hand, if the amount is too small, the effects of the present invention may not be sufficiently exerted. If the amount is too large, the resistance may increase and the output and load characteristics may decrease.
In addition, the compound represented by General formula (1) may use what was synthesize | combined by the known method, or may use a commercially available thing.

2-4. Compounds (A) to (C) The non-aqueous electrolyte solution of the present invention preferably contains at least one compound of (A) to (C) together with the compound represented by the general formula (1). By using these compounds in combination, a high-quality composite film having a high protective ability is formed on the electrode surface, and the cycle characteristics and storage characteristics of the non-aqueous electrolyte battery are greatly improved. In particular, the improvement effect is remarkable under high voltage conditions.

The non-aqueous electrolyte of the present invention may contain all of the compounds (A), (B), and (C), or may contain a plurality of compounds belonging to (A). A plurality of compounds belonging to (C) may be included, and a plurality of compounds belonging to (C) may be included.
2-4-1. (A) Compound represented by Li _α XO _n F _m The non-aqueous electrolyte solution of the present invention includes a compound represented by Li _α XO _n F _m (hereinafter referred to as ( It is preferable to contain A). X is an element of any of Groups 13, 15, and 16 in the second or third period of the periodic table, and represents α = 1 to 2, n = 1 to 3, and m = 1 to 2.

X is preferably phosphorus or sulfur, and specific examples include Li ₂ PO ₃ F, LiPO ₂ F ₂ , and LiSO ₃ F. The compound (A) is a lithium salt, but does not include the lithium salt described in “2-1. Electrolyte”.
There is no limitation on the amount of the compound (A) to be added to the whole non-aqueous electrolyte of the present invention, and it is optional as long as the effects of the present invention are not significantly impaired. 001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 15% by mass or less, preferably 12% by mass or less, more preferably 10% by mass or less. Let me. When the above range is satisfied, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature storage characteristics are further improved. On the other hand, if it is too much, it may be deposited at low temperature to deteriorate the battery characteristics, and if it is too little, the effect of improving the low-temperature characteristics, cycle characteristics, high-temperature storage characteristics, etc. may not be sufficiently exhibited.

The preparation of the electrolytic solution in the case where the compound (A) is contained in the electrolytic solution is a method of adding to the electrolytic solution containing the compound (A) synthesized separately by a known method, or in the electrolytic solution (A) The method of generating a compound is mentioned. For example, if the LiPO ₂ F _2, allowed to coexist water into cell components such as active material and the electrode plate to be described later, LiPO ₂ F in the system during the time of assembling a battery using the electrolytic solution containing LiPF _{6 2} can be generated.

The method for measuring the content of the compound (A) in the non-aqueous electrolyte solution and the non-aqueous electrolyte battery is not particularly limited, and any known method can be used. In the case of LiPO ₂ F ₂ , it can be measured using ion chromatography, F nuclear magnetic resonance spectroscopy (hereinafter sometimes abbreviated as NMR), and the like.
2-4-2. (B) Compound Represented by General Formula (3) The non-aqueous electrolyte solution of the present invention includes a compound represented by general formula (3) together with a compound represented by general formula (1) (hereinafter referred to as (B) (It is also referred to as this compound).

(In the general formula (3), A represents an alkali metal, M is a transition metal, a group 13, 14 or 15 element of the periodic table, b is 1 to 3, m is 1 to 3, and n is 0 to 6, q represents 0 or 1, respectively, and R ⁵ represents alkylene having 1 to 10 carbons, halogenated alkylene having 1 to 10 carbons, arylene having 6 to 20 carbons, or 6 to 20 carbons. A halogenated arylene (these alkylene and arylene may have a substituent or a hetero atom in the structure thereof, and m R ^{5 s} may be bonded to each other), and R ⁶ is , Halogen, alkyl having 1 to 10 carbons, alkyl halide having 1 to 10 carbons, aryl having 6 to 20 carbons, halogenated aryl having 6 to 20 carbons, or X ³ R ⁷ (these alkyls and aryls) Is The structure may have a substituent or a heteroatom, and n R ^{6 s} may be bonded to each other to form a ring.), X ¹ , X ² , X ³ Is O, S, or NR ⁸ , and R ⁷ and R ⁸ are each independently hydrogen, alkyl having 1 to 10 carbons, halogenated alkyl having 1 to 10 carbons, or 6 to 20 carbons Aryl, or an aryl halide having 6 to 20 carbon atoms (these alkyl and aryl may have a substituent or a hetero atom in the structure, or a plurality of R ⁷ and R ⁸ are bonded to each other) And may form a ring.))

Specifically, lithium bis (oxalato) borate, potassium bis (oxalato) borate, sodium bis (oxalato) borate, lithium difluorooxalatoborate, potassium difluorooxalatoborate, sodium difluorooxalatoborate, lithium tris (oxalato) phosphate , Potassium tris (oxalato) phosphate, sodium tris (oxalato) phosphate, lithium difluorobis (oxalato) phosphate, potassium difluorobis (oxalato) phosphate, sodium difluorobis (oxalato) phosphate, lithium tetrafluorooxalato phosphate, potassium tetrafluorooxax Latophosphate, sodium tetrafluorooxalatophosphate, lithium Su (malonato) borate, potassium bis (malonato) borate, sodium bis (malonato) borate, lithium difluoromalonatoborate, potassium difluoromalonatoborate, sodium difluoromalonatoborate, lithium tris (malonato) phosphate, potassium tris (malonato) Phosphate, sodium tris (malonato) phosphate, lithium difluorobis (malonato) phosphate, potassium difluorobis (malonato) phosphate, sodium difluorobis (malonate) phosphate, lithium tetrafluoromalonate phosphate, potassium tetrafluoromalonate phosphate, sodium tetrafluoro Malonate phosphate, lithium oxalatomalonatoborate, potassium oxalatomalo Toborate, sodium oxalate malonatoborate, lithium (bisoxalato) (malonato) phosphate, lithium (oxalato) (bismalonate) phosphate, sodium (bisoxalato) (malonato) phosphate, sodium (oxalato) (bismalonate) phosphate, potassium (bisoxalato) (malonate) ) Phosphate, potassium (oxalato) (bismalonate) phosphate,
Lithium difluoro (oxalato) (malonato) phosphate, potassium difluoro (oxalato) (malonato) phosphate, sodium difluoro (oxalato) (malonato) phosphate.

  Among these, lithium difluorooxalatoborate, lithium bis (oxalato) borate, lithium tetrafluorooxalatophosphate, lithium difluorobis (oxalato) phosphate, and lithium tris (oxalato) phosphate shown below are particularly preferable. It should be noted that the compound (B) does not include the lithium salt described in “1-1.

  Moreover, the compound represented by the compound represented by General formula (3) may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios.

  There is no limitation on the amount of the compound (B) to be added to the whole non-aqueous electrolyte of the present invention, and it is optional as long as the effects of the present invention are not significantly impaired. 001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 15% by mass or less, preferably 12% by mass or less, more preferably 10% by mass or less. Let When the above range is satisfied, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature storage characteristics are further improved. On the other hand, if it is too much, it may be deposited at low temperature to deteriorate the battery characteristics, and if it is too little, the effect of improving the low-temperature characteristics, cycle characteristics, high-temperature storage characteristics, etc. may not be sufficiently exhibited.

The lithium salts represented by (A) and (B) may be used alone or in combination of two or more together with the lithium salt described in “2-1. Electrolyte”. A preferable example in the case of using two or more kinds in combination is LiPF ₆ and LiBF ₄ , LiPF ₆ and FSO ₃ Li, LiPF.
₆ and LiPO ₂ F ₂ , LiPF ₆ and LiN (FSO ₂ ) ₂ , LiPF ₆ and LiN (CF ₃ SO ₂ ) ₂ , LiPF ₆ and lithium bisoxalatoborate, LiPF ₆ and lithium difluorooxalatoborate, LiPF ₆ and Lithium tetrafluorooxalato phosphate, LiPF ₆ and lithium difluorobisoxalatophosphate, LiPF ₆ and lithium tris (oxalato) phosphate, LiPF ₆ and FSO ₃ Li and LiPO ₂ F ₂ , LiPF ₆ and FSO ₃ Li and lithium bisoxa Latoborate, LiPF ₆ and FSO ₃ Li and lithium tetrafluorooxalate phosphate, LiPF ₆ and FSO ₃ Li and lithium difluorobisoxalatophosphate, LiPF ₆ and FSO ₃ Li and lithium Lis (oxalato) phosphate, LiPF ₆ and LiPO ₂ F ₂ and lithium bisoxalatoborate, LiPF ₆ and LiPO ₂ F ₂ and lithium tetrafluorooxalate phosphate, LiPF ₆ and LiPO ₂ F ₂ and lithium difluorobisoxalatophosphate , LiPF ₆ , LiPO ₂ F ₂ and lithium tris (oxalato) phosphate are used in combination, and have the effect of improving load characteristics and cycle characteristics.

Among these, LiPF ₆ and FSO ₃ Li, LiPF ₆ and LiPO ₂ F ₂ , LiPF ₆ and lithium bisoxalatoborate, LiPF ₆ and lithium tetrafluorooxalate phosphate, LiPF ₆ and lithium tris (oxalato) phosphate, LiPF ₆ and lithium difluorobisoxalatophosphate, LiPF ₆ and FSO ₃ Li and LiPO ₂ F ₂ , LiPF ₆ and FSO ₃ Li and lithium bisoxalatoborate, LiPF ₆ and LiPO ₂ F ₂ and lithium bisoxalatoborate, LiPF ₆ and _FSO 3 Li and lithium tris (oxalato) phosphate, LiPF ₆ and _FSO 3 Li and lithium difluoro bis oxa Lato phosphate, LiPF ₆ and LiPO ₂ F ₂ and lithium tris (oxalato Phosphate, LiPF ₆ and LiPO ₂ F ₂ and the combination of lithium difluoro bis oxa Lato phosphate is particularly preferred because the effect is remarkable.

LiPF ₆ and LiBF ₄ , FSO ₃ Li, LiPO ₂ F ₂ , LiN (FSO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) ₂ , lithium bisoxalatoborate, lithium difluorooxalatoborate, lithium tetrafluorooxalatophosphate, When lithium tris (oxalato) phosphate, lithium difluorobisoxalatophosphate, etc. are used together, LiBF ₄ , FSO ₃ Li, LiPO ₂ F ₂ , LiN (FSO ₂ ) ₂ , LiN ( CF ₃ SO ₂ ) ₂ , lithium bisoxalatoborate, lithium difluorooxalatoborate, lithium tris (oxalato) phosphate, lithium tetrafluorooxalatophosphate, lithium difluorobisoxalate There is no limit to the amount of phosphate or the like, and it is optional as long as the effects of the present invention are not significantly impaired. %, While the upper limit is usually 12% by mass or less, preferably 10% by mass or less. On the other hand, even in the case of combined use of LiPF ₆ and LiPO ₂ F ₂ , there is no limit to the amount of LiPO ₂ F ₂ blended with respect to 100% by mass of the entire non-aqueous electrolyte, and it is optional as long as the effects of the present invention are not significantly impaired. With respect to the non-aqueous electrolyte solution of the present invention, it is usually 0.001% by mass or more, preferably 0.01% by mass or more, while its upper limit is usually 10% by mass or less, preferably 5% by mass or less. Within this range, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature characteristics are improved. On the other hand, if it is too much, it may be deposited at low temperature to deteriorate the battery characteristics, and if it is too little, the effect of improving the low temperature characteristics, cycle characteristics, high temperature storage characteristics, etc. may be reduced.

Here, the preparation of the electrolyte solution in the case of incorporating the LiPO ₂ F ₂ in the electrolyte solution, Ya separately active material method and later be added to the electrolytic solution containing LiPF ₆ and LiPO ₂ F ₂ synthesized by a known method A method of generating LiPO ₂ F ₂ in the system when water is allowed to coexist in a battery component such as an electrode plate and assembling a battery using an electrolyte containing LiPF ₆ is used. This method may be used.

The method for measuring the content of LiPO ₂ F ₂ in the non-aqueous electrolyte and the non-aqueous electrolyte battery is not particularly limited, and any known method can be used. Examples include ion chromatography and F nuclear magnetic resonance spectroscopy (hereinafter sometimes abbreviated as NMR).
2-4-3. (C) Carbonate having at least one carbon-carbon unsaturated bond or fluorine atom

The nonaqueous electrolytic solution of the present invention contains a carbonate having at least one of a carbon-carbon unsaturated bond or a fluorine atom (hereinafter also referred to as a compound of (C)) together with the compound represented by the general formula (1). It is preferable to do. The compound (C) is not particularly limited as long as it is a carbonate having a carbon-carbon unsaturated bond or a fluorine atom, and may be a chain or a ring. However, the compound represented by the general formula (1) is not included in this.
The compound of C) may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios.

<Cyclic carbonate having a carbon-carbon unsaturated bond>
The cyclic carbonate having a carbon-carbon unsaturated bond (hereinafter also referred to as an unsaturated cyclic carbonate) has vinylene carbonates having an unsaturated bond in the skeleton of the cyclic carbonate, or has an aromatic ring or a carbon-carbon unsaturated bond. Examples thereof include ethylene carbonates substituted with a substituent, phenyl carbonates, vinyl carbonates, allyl carbonates, catechol carbonates and the like.

  As vinylene carbonates, vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, phenyl vinylene carbonate, 4,5-diphenyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4 , 5-diallyl vinylene carbonate.

  Specific examples of ethylene carbonates substituted with an aromatic ring or a substituent having a carbon-carbon unsaturated bond include vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-5-vinyl ethylene carbonate, 4- Allyl-5-vinylethylene carbonate, phenylethylene carbonate, 4,5-diphenylethylene carbonate, 4-phenyl-5-vinylethylene carbonate, 4-allyl-5-phenylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene Examples thereof include carbonate and 4-methyl-5-allylethylene carbonate.

Examples of unsaturated cyclic carbonates include vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, vinyl ethylene carbonate, 4,5-divinylethylene carbonate, 4-methyl-5-vinylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene carbonate, 4-methyl-5-allylethylene carbonate, 4-allyl-5-vinylethylene carbonate Vinylene carbonate and vinyl ethylene carbonate are particularly preferred. Since these form a stable interface protective film, they are more preferably used.
Moreover, an unsaturated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.

<A chain carbonate having a carbon-carbon unsaturated bond>
The chain carbonate having a carbon-carbon unsaturated bond (hereinafter also referred to as an unsaturated chain carbonate) is a chain carbonate having a carbon-carbon unsaturated bond or a chain substituted with a substituent having an aromatic ring. And carbonated carbonates.

As chain carbonates having a chain hydrocarbon having a carbon-carbon unsaturated bond,
Methyl vinyl carbonate, ethyl vinyl carbonate, divinyl carbonate, methyl-1-propenyl carbonate, ethyl-1-propenyl carbonate, di-1-propenyl carbonate, methyl (1-methylvinyl) carbonate, ethyl (1-methylvinyl) carbonate, Di (1-methylvinyl) carbonate, methyl-2-propenyl carbonate, ethyl-2-propenyl carbonate, di (2-propenyl) carbonate, 1-butenylmethyl carbonate, 1-butenylethyl carbonate, di (1-butenyl) ) Carbonate, methyl (1-methyl-1-propenyl) carbonate, ethyl (1-methyl-1-propenyl) carbonate, di (1-methyl-1-propenyl) carbonate, methyl-1-ethylvinyl -Bonate, ethyl-1-ethyl vinyl carbonate, di-1-ethyl vinyl carbonate, methyl (2-methyl-1-propenyl) carbonate, ethyl (2-methyl-1-propenyl) carbonate, di (2-methyl-1- Propenyl) carbonate, 2-butenyl methyl carbonate, 2-butenyl ethyl carbonate, di-2-butenyl carbonate, methyl (1-methyl-2-propenyl) carbonate, ethyl (1-methyl-2-propenyl) carbonate, Di (1-methyl-2-propenyl) carbonate, methyl (2-methyl-2-propenyl) carbonate, ethyl (2-methyl-2-propenyl) carbonate, di (2-methyl-2-propenyl) carbonate, methyl ( 1,2-dimethyl-1-propenyl) carbo , Ethyl (1,2-dimethyl-1-propenyl) carbonate, di (1,2-dimethyl-1-propenyl) carbonate, ethynyl methyl carbonate, ethyl ethynyl carbonate, diethynyl carbonate, methyl-1-propynyl carbonate, Ethyl-1-propynyl carbonate, di-1-propynyl carbonate, methyl-2-propynyl carbonate, ethyl-2-propynyl carbonate, di-2-propynyl carbonate, 1-butynylmethyl carbonate, 1-butynylethyl carbonate, di -1-butynyl carbonate, 2-butynyl methyl carbonate, 2-butynyl ethyl carbonate, di-2-butynyl carbonate, methyl (1-methyl-2-propynyl) carbonate, ethyl (1-methyl-2-propyl) Lopinyl) carbonate, di (1-methyl-2-propynyl) carbonate, 3-butynylmethyl carbonate, 3-butynylethyl carbonate, di-3-butynyl carbonate, methyl (1,1-dimethyl-2-propynyl) Carbonate, ethyl (1,1-dimethyl-2-propynyl) carbonate, dityl (1,1-dimethyl-2-propynyl) carbonate, methyl (1,3-dimethyl-2-propynyl) carbonate, ethyl (1,3- Dimethyl-2-propynyl) carbonate, dityl (1,3-dimethyl-2-propynyl) carbonate, methyl (1,2,3-trimethyl-2-propynyl) carbonate, ethyl (1,2,3-trimethyl-2- Propynyl) carbonate, dityl (1,2,3-trimethyl-2-propiyl) Le) carbonate, and the like.

As chain carbonates substituted with a substituent having an aromatic ring,
Methyl phenyl carbonate, ethyl phenyl carbonate, phenyl vinyl carbonate, allyl phenyl carbonate, enethyl phenyl carbonate, 2-propenyl phenyl carbonate, diphenyl carbonate, methyl (2-methylphenyl) carbonate, ethyl (2-methylphenyl) carbonate, (2 -Methylphenyl) vinyl carbonate, allyl (2-methylphenyl) carbonate, enethyl (2-methylphenyl) carbonate, 2-propenyl (2-methylphenyl) carbonate, di (2-methylphenyl) carbonate, methyl (3-methyl) Phenyl) carbonate, ethyl (3-methylphenyl) carbonate, (3-methylphenyl) vinyl carbonate, allyl (3-methylphenyl) carbonate , Enethyl (3-methylphenyl) carbonate, 2-propenyl (3-methylphenyl) carbonate, di (3-methylphenyl) carbonate, methyl (4-methylphenyl) carbonate, ethyl (4-methylphenyl) carbonate, (4 -Methylphenyl) vinyl carbonate, allyl (4-methylphenyl) carbonate, enethyl (4-methylphenyl) carbonate, 2-propenyl (4-methylphenyl) carbonate, di (4-methylphenyl) carbonate, benzylmethyl carbonate, benzyl Ethyl carbonate, benzyl phenyl carbonate, benzyl vinyl carbonate, benzyl-2-propenyl carbonate, benzyl ethynyl carbonate, benzyl-2-propynyl carbonate, dibenzyl -Bonate, methyl (2-cyclohexylphenyl) carbonate, methyl (3-cyclohexylphenyl) carbonate, methyl (4-cyclohexylphenyl) carbonate, ethyl (2-cyclohexylphenyl) carbonate, di (2-cyclohexylphenyl) carbonate, etc. It is done.

  Among the above unsaturated chain carbonates, methyl vinyl carbonate, ethyl vinyl carbonate, divinyl carbonate, allyl methyl carbonate, allyl ethyl carbonate, diallyl carbonate, 2-propynyl methyl carbonate, 2-propynyl ethyl carbonate, 1-methyl- 2-propynylmethyl carbonate, 1-methyl-2-propynylethyl carbonate, 1,1-dimethyl-2-propynylmethyl carbonate, dipropynyl carbonate, 2-butynylmethyl carbonate, 1-methyl-2-butynylmethyl carbonate, 1,1-dimethyl-2-butynylmethyl carbonate, dibutynyl carbonate, methylphenyl carbonate, ethylphenyl carbonate, phenyl vinyl carbonate, Ryl phenyl carbonate, diphenyl carbonate, benzyl methyl carbonate, benzyl ethyl carbonate, benzyl phenyl carbonate, allyl benzyl carbonate, dibenzyl carbonate, 2-propynyl phenyl carbonate, 2-butynyl phenyl carbonate are preferred, methyl vinyl carbonate, ethyl vinyl carbonate, Divinyl carbonate, allyl methyl carbonate, allyl ethyl carbonate, diallyl carbonate, 2-propynyl methyl carbonate, 1-methyl-2-propynyl methyl carbonate, 1,1-dimethyl-2-propynyl methyl carbonate, dipropynyl carbonate, 2-butynyl Methyl carbonate, 1-methyl-2-butynyl methyl carbonate, 1,1-dimethyl 2-butynyl methyl carbonate, dibutyl alkenyl carbonate, methyl phenyl carbonate, ethyl phenyl carbonate, diphenyl carbonate is particularly preferred. Since these form a stable interface protective film, they are more preferably used.

Moreover, an unsaturated chain carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.
<Fluorinated carbonate>
As the carbonate having a fluorine atom, both a chain carbonate having a fluorine atom (hereinafter also referred to as a fluorinated chain carbonate) and a cyclic carbonate having a fluorine atom (hereinafter also referred to as a fluorinated cyclic carbonate) can be used. .

In addition, although the linear or cyclic carbonate which has a fluorine atom is mentioned above as a solvent of nonaqueous electrolyte, it can also be used as an adjuvant.
The number of fluorine atoms in the fluorinated chain carbonate is not particularly limited as long as it is 1 or more, but is usually 6 or less, preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon or may be bonded to different carbons. Examples of the fluorinated chain carbonate include a fluorinated dimethyl carbonate derivative, a fluorinated ethyl methyl carbonate derivative, and a fluorinated diethyl carbonate derivative.

Examples of the fluorinated dimethyl carbonate derivative include fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, bis (difluoro) methyl carbonate, bis (trifluoromethyl) carbonate, and the like.
Fluorinated ethyl methyl carbonate derivatives include 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2-trimethyl Examples include fluoroethyl methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate, and ethyl trifluoromethyl carbonate.

  Fluorinated diethyl carbonate derivatives include ethyl- (2-fluoroethyl) carbonate, ethyl- (2,2-difluoroethyl) carbonate, bis (2-fluoroethyl) carbonate, ethyl- (2,2,2-trifluoro). Ethyl) carbonate, 2,2-difluoroethyl-2′-fluoroethyl carbonate, bis (2,2-difluoroethyl) carbonate, 2,2,2-trifluoroethyl-2′-fluoroethyl carbonate, 2,2, Examples include 2-trifluoroethyl-2 ′, 2′-difluoroethyl carbonate, bis (2,2,2-trifluoroethyl) carbonate, and the like.

As the fluorinated chain carbonate, 2,2,2-trifluoroethyl methyl carbonate and bis (2,2,2-trifluoroethyl) carbonate are particularly preferable.
Moreover, a fluorinated chain carbonate may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios.
Examples of the fluorinated cyclic carbonate include derivatives of cyclic carbonates having an alkylene group having 2 to 6 carbon atoms, such as ethylene carbonate derivatives. Examples of the ethylene carbonate derivative include fluorinated products of ethylene carbonate or ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms), and particularly those having 1 to 8 fluorine atoms. Is preferred.

  Specifically, monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4- Fluoro-5-methylethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4- (fluoromethyl) -ethylene carbonate, 4- (difluoromethyl) -ethylene carbonate, 4- (trifluoromethyl) -ethylene carbonate 4- (fluoromethyl) -4-fluoroethylene carbonate, 4- (fluoromethyl) -5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,5-difluoro-4,5-dimethyl Le ethylene carbonate, 4,4-difluoro-5,5-dimethylethylene carbonate.

Examples of the fluorinated cyclic carbonate include monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, and 4,5-
Particularly preferred is at least one selected from the group consisting of difluoro-4,5-dimethylethylene carbonate. These provide high ionic conductivity and preferably form an interface protective coating.
Moreover, a fluorinated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.

<Cyclic carbonate having both a carbon-carbon unsaturated bond and a fluorine atom>
The cyclic carbonate having both a carbon-carbon unsaturated bond and a fluorine atom (hereinafter also referred to as a fluorinated unsaturated cyclic carbonate) is a fluorinated vinylene carbonate derivative, an aromatic ring or a substituent having a carbon-carbon unsaturated bond. Examples thereof include substituted fluorinated ethylene carbonate derivatives.

  Fluorinated vinylene carbonate derivatives include 4-fluoro vinylene carbonate, 4-fluoro-5-methyl vinylene carbonate, 4-fluoro-5-phenyl vinylene carbonate, 4-allyl-5-fluoro vinylene carbonate, 4-fluoro-5- Examples include vinyl vinylene carbonate, 4-fluoro-5-vinyl vinylene carbonate, 4-allyl-5-fluoro vinylene carbonate, and the like.

  Examples of the fluorinated ethylene carbonate derivative substituted with an aromatic ring or a substituent having a carbon-carbon unsaturated bond include 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene carbonate, 4-fluoro-5. -Vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-5-vinylethylene carbonate, 4,4-difluoro-5-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate 4,5-difluoro-4-allylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate , 4,5-Diff Oro-4,5-diallylethylene carbonate, 4-fluoro-4-phenylethylene carbonate, 4-fluoro-5-phenylethylene carbonate, 4,4-difluoro-5-phenylethylene carbonate, 4,5-difluoro-4- Examples thereof include phenylethylene carbonate.

Examples of the fluorinated unsaturated cyclic carbonate include 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4 , 4-Difluoro-5-vinylethylene carbonate, 4,4-difluoro-5-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-allylethylene carbonate, 4-fluoro -4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, 4,5-difluoro-4,5-diallylethylene carbonate are preferred. . Since these form a stable interface protective film, they are more preferably used.
Moreover, a fluorinated unsaturated cyclic carbonate may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios.

<Chain carbonate having both carbon-carbon unsaturated bond and fluorine atom>
Examples of the chain carbonate having both a carbon-carbon unsaturated bond and a fluorine atom (hereinafter also referred to as fluorinated unsaturated chain carbonate) include 1-fluorovinyl methyl carbonate, 2-fluorovinyl methyl carbonate, 1,2- Difluorovinylmethyl carbonate, ethyl-1-fluorovinyl carbonate, ethyl-2-fluorovinyl carbonate, ethyl-1,2-difluorovinyl carbonate, bis (1-fluorovinyl) carbonate, bis (2-fluorovinyl) carbonate, bis (1,2-difluorovinyl) carbonate, 1-fluoro-1-propenylmethyl carbonate, 2-fluoro-1-propenylmethyl carbonate, 3-fluoro-1-propenylmethyl carbonate, 1,2-difluoro-1-pro Nylmethyl carbonate, 1,3-difluoro-1-propenylmethyl carbonate, 2,3-difluoro-1-propenylmethyl carbonate, 3,3-difluoro-1-propenylmethyl carbonate, 1-fluoro-2-propenylmethyl carbonate, 2-fluoro-2-propenylmethyl carbonate, 3-fluoro-2-propenylmethyl carbonate, 1,1-difluoro-2-propenylmethyl carbonate, 1,2-difluoro-2-propenylmethyl carbonate, 1,3-difluoro- 2-propenylmethyl carbonate, 2,3-difluoro-2-propenylmethyl carbonate, fluoroethynylmethyl carbonate, 3-fluoro-1-propynylmethyl carbonate, 1-fluoro-2-propynylmethyl Boneto, 3-fluoro-2-propynyl methyl carbonate, and the like.

Moreover, a fluorinated unsaturated chain carbonate may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios.
The molecular weight of the compound (C) is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired, but is preferably 50 or more and 250 or less. In the case of unsaturated cyclic carbonates, more preferably 80 or more and 150 or less, and in the case of fluorinated unsaturated cyclic carbonates, more preferably 100 or more and 200 or less. If it is this range, the solubility of the cyclic carbonate which has a carbon-carbon unsaturated bond with respect to a non-aqueous electrolyte solution will be easy to be ensured, and the effect of this invention will fully be expressed easily.

As the compound (C), one type may be used alone, or two or more types may be used in any combination and ratio.
The blending amount in the case of unsaturated cyclic carbonate is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and further preferably 0.1% by mass or more in 100% by mass of the non-aqueous solvent. Moreover, it is preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less.

The blending amount in the case of fluorinated chain carbonate or fluorinated cyclic carbonate can follow the blending amount described in [0068] as a solvent as it is, but is preferably less than 50% by weight in 100% by weight of the non-aqueous solvent. Further, when used as an auxiliary, it may be the same as the blending amount of the fluorinated unsaturated cyclic carbonate or fluorinated unsaturated chain carbonate described later.
The blending amount in the case of fluorinated unsaturated cyclic carbonate or fluorinated unsaturated chain carbonate is usually in 100% by mass of the non-aqueous electrolyte, preferably 0.01% by mass or more, more preferably 0.1% by mass. % Or more, more preferably 0.2% by mass or more, preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less.

Within this range, the non-aqueous electrolyte battery tends to exhibit a sufficient cycle characteristics improvement effect, and the high temperature storage characteristics deteriorate, the amount of gas generated increases, and the discharge capacity maintenance ratio decreases. Easy to avoid.
The proportion of the compound represented by the general formula (1) and the compound (C) is not particularly limited. However, when the compound (C) is a carbonate having an unsaturated bond, the compound has an unsaturated bond. When the total content of carbonate is [M _u ] and the total content of the compound represented by the general formula (1) is [M ₍₁₎ ], usually [M ₍₁₎ ] / [M _u ] Is 100 to 0.01, more preferably 20 to 0.05, and still more preferably 10 to 0.1.

1-5. Auxiliary In the non-aqueous electrolyte battery defined in the present invention, an auxiliary may be appropriately used depending on the purpose. Examples of the auxiliary agent include an overcharge inhibitor and other auxiliary agents shown below.
<Overcharge prevention agent>
In the non-aqueous electrolyte solution of the present invention, an overcharge inhibitor can be used in order to effectively prevent the battery from bursting or igniting when the non-aqueous electrolyte battery is overcharged.

  As an overcharge inhibitor, aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, dibenzofuran; 2-fluorobiphenyl, Partially fluorinated products of the above aromatic compounds such as o-cyclohexylfluorobenzene and p-cyclohexylfluorobenzene; 2,4-difluoroanisole, 2,5-difluoroanisole, 2,6-difluoroanisole, 3,5-difluoroanisole and the like And a fluorine-containing anisole compound. Of these, aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, terphenyl partially hydrogenated, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, and dibenzofuran are preferable. These may be used alone or in combination of two or more. When two or more kinds are used in combination, in particular, a combination of cyclohexylbenzene and t-butylbenzene or t-amylbenzene, biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, Using at least one selected from aromatic compounds not containing oxygen, such as t-amylbenzene, and at least one selected from oxygen-containing aromatic compounds such as diphenyl ether, dibenzofuran, and the like is an overcharge prevention property and a high temperature storage property. From the standpoint of balance.

  The amount of the overcharge inhibitor is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The overcharge inhibitor is preferably 0.1% by mass or more and 5% by mass or less in 100% by mass of the non-aqueous electrolyte solution. If it is this range, it will be easy to fully express the effect of an overcharge inhibiting agent, and it will be easy to avoid the situation where the battery characteristics, such as a high temperature storage characteristic, fall. The overcharge inhibitor is more preferably 0.2% by mass or more, further preferably 0.3% by mass or more, particularly preferably 0.5% by mass or more, and more preferably 3% by mass or less, still more preferably. Is 2% by mass or less.

<Other auxiliaries>
Other known auxiliary agents can be used in the non-aqueous electrolyte solution of the present invention. Other auxiliaries include carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate; succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, anhydrous Carboxylic anhydrides such as itaconic acid, diglycolic anhydride, cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride and phenylsuccinic anhydride; 2,4,8,10-tetraoxaspiro [5.5 ] Spiro compounds such as undecane, 3,9-divinyl-2,4,8,10-tetraoxaspiro [5.5] undecane; ethylene sulfite, 1,3-propane sultone, 1-fluoro-1,3- Propane sultone, 2-fluoro-1,3-propane sultone, 3-ph Oro-1,3-propane sultone, 1-propene-1,3-sultone, 1-fluoro-1-propene-1,3-sultone, 2-fluoro-1-propene-1,3-sultone, 3-fluoro -1-propene-1,3-sultone, 1,4-butanesultone, 1-butene-1,4-sultone, 3-butene-1,4-sultone, methyl fluorosulfonate, ethyl fluorosulfonate, methanesulfonic acid Sulfur-containing compounds such as methyl, ethyl methanesulfonate, busulfan, sulfolane, sulfolene, diphenylsulfone, N, N-dimethylmethanesulfonamide, N, N-diethylmethanesulfonamide; 1-methyl-2-pyrrolidinone, 1-methyl 2-piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidino And nitrogen-containing compounds such as N-methylsuccinimide; acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, lauronitrile, 2-methylbutyronitrile, trimethylacetonitrile, hexanenitrile, cyclopentanecarbo Nitrile, cyclohexanecarbonitrile, acrylonitrile, methacrylonitrile, crotononitrile, 3-methylcrotononitrile, 2-methyl-2-butenenitryl, 2-pentenenitrile, 2-methyl-2-pentenenitrile, 3-methyl 2-pentenenitrile, 2-hexenenitrile, fluoroacetonitrile, difluoroacetonitrile, trifluoroacetonitrile, 2-fluoropropionitrile, 3-fluoropropionitrile, 2 , 2-difluoropropionitrile, 2,3-difluoropropionitrile, 3,3-difluoropropionitrile, 2,2,3-trifluoropropionitrile, 3,3,3-trifluoropropionitrile, 3, Cyano groups such as 3′-oxydipropionitrile, 3,3′-thiodipropionitrile, 1,2,3-propanetricarbonitrile, 1,3,5-pentanetricarbonitrile, pentafluoropropionitrile, etc. Compound having one: malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimeonitrile, suberonitrile, azeronitrile, sebacononitrile, undecandinitrile, dodecandinitrile, methylmalononitrile, ethylmalononitrile, isopropylmalononitrile, tert-butylmalononito , Methyl succinonitrile, 2,2-dimethyl succinonitrile, 2,3-dimethyl succinonitrile, trimethyl succinonitrile, tetramethyl succinonitrile 3,3 ′-(ethylenedioxy) dipropionitrile, 3 , 3 ′-(ethylenedithio) dipropionitrile and other compounds having two cyano groups; 1,12-diisocyanatododecane, 1,11-diisocyanatoundecane, 1,10-diisocyanatodecane, 1, Compounds having two isocyanate groups such as 9-diisocyanatononane, 1,8-diisocyanatooctane, 1,7-isocyanatoheptane, 1,6-diisocyanatohexane; heptane, octane, nonane, decane, Hydrocarbon compounds such as cycloheptane, fluorobenzene, difluorobenzene, hexafluorobenzene Fluorine-containing aromatic compounds such as benzene and benzotrifluoride. These may be used alone or in combination of two or more. By adding these auxiliaries, capacity maintenance characteristics and cycle characteristics after high temperature storage can be improved.

  The blending amount of other auxiliary agents is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The other auxiliary agent is preferably 0.01% by mass or more and 5% by mass or less in 100% by mass of the non-aqueous electrolyte solution. Within this range, the effects of other auxiliaries can be sufficiently exhibited, and it is easy to avoid a situation in which battery characteristics such as high-load discharge characteristics deteriorate. The blending amount of other auxiliaries is more preferably 0.1% by mass or more, further preferably 0.2% by mass or more, more preferably 3% by mass or less, and further preferably 1% by mass or less. .

  The non-aqueous electrolyte solution described above includes those existing inside the non-aqueous electrolyte battery according to the present invention. Specifically, the components of the non-aqueous electrolyte solution such as lithium salt, solvent, and auxiliary agent are separately synthesized, and the non-aqueous electrolyte solution is prepared from what is substantially isolated by the method described below. In the case of a nonaqueous electrolyte solution in a nonaqueous electrolyte battery obtained by pouring into a separately assembled battery, the components of the nonaqueous electrolyte solution of the present invention are individually placed in the battery, In order to obtain the same composition as the non-aqueous electrolyte solution of the present invention by mixing in a non-aqueous electrolyte battery, the compound constituting the non-aqueous electrolyte solution of the present invention is further generated in the non-aqueous electrolyte battery. The case where the same composition as the aqueous electrolyte is obtained is also included.

3. Battery Configuration The non-aqueous electrolyte battery of the present invention is suitable for use as an electrolyte for a secondary battery, for example, a lithium secondary battery, among non-aqueous electrolyte batteries. Hereinafter, a non-aqueous electrolyte battery using the non-aqueous electrolyte of the present invention will be described.
The non-aqueous electrolyte secondary battery of the present invention can adopt a known structure. Typically, the negative electrode and the positive electrode capable of occluding and releasing ions (for example, lithium ions), and the non-aqueous electrolyte of the present invention described above. An aqueous electrolyte solution.

4). Positive electrode <Positive electrode active material>
The positive electrode active material used for the positive electrode is described below.
(composition)
The positive electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions. For example, a material containing lithium and at least one transition metal is preferable. Specific examples include lithium transition metal composite oxides and lithium-containing transition metal phosphate compounds.

V, Ti, Cr, Mn, Fe, Co, Ni, Cu and the like are preferable as the transition metal of the lithium transition metal composite oxide, and specific examples include lithium-cobalt composite oxides such as LiCoO ₂ , LiMnO ₂ , Examples thereof include lithium / manganese composite oxides such as LiMn ₂ O ₄ and Li ₂ MnO ₄ , lithium / nickel composite oxides such as LiNiO ₂ , and the like. Further, some of the transition metal atoms that are the main components of these lithium transition metal composite oxides are Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, and Si. Specific examples include lithium-nickel-cobalt-aluminum composite oxides, lithium-cobalt-nickel composite oxides, lithium-cobalt-manganese composite oxides, lithium- Nickel / manganese composite oxide, lithium / nickel / cobalt / manganese composite oxide, and the like can be given. Among these, lithium / nickel / manganese composite oxide and lithium / nickel / cobalt / manganese composite oxide are preferable because of good battery characteristics.

Specific examples of the substituted ones include, for example, Li _{1 + a} Ni _0.5 Mn _0.5 O ₂ , Li _{1 + a} Ni _0.8 Co _0.2 O ₂ , Li _{1 + a} Ni _0.85 Co _0.10 Al _{0. 05} O ₂ , Li _{1 + a} Ni _0.33 Co _0.33 Mn _0.33 O ₂ , Li _{1 + a} Ni _0.45 Mn _0.45 Co _0.1 O ₂ , Li _{1 + a} Ni _0.475 Mn _0.475 Co _{0 .05} O ₂ , Li _{1 + a} Mn _1.8 Al _0.2 O ₄ , Li _{1 + a} Mn ₂ O ₄ , Li _{1 + a} Mn _1.5 Ni _0.5 O ₄ , xLi ₂ MnO _3. (1-x) Li _{1 + a} MO ₂ (M = transition metal, such as a metal selected from the group consisting of Li, Ni, Mn, and Co) (a; 0 <a ≦ 3.0). The ratio of these substituted metal elements in the composition formula is appropriately adjusted depending on the relationship between the battery characteristics of the battery using the element and the cost of the material.

The lithium-containing transition metal phosphate compound is LixMPO ₄ (M = a kind of element selected from the group consisting of Group 4 to Group 11 transition metals in the periodic table, x is 0 <x <1.2). As the transition metal (M), V, Ti, Cr, Mg, Zn, Ca, Cd, Sr, Ba, Co, Ni,
It is preferably at least one element selected from the group consisting of Fe, Mn and Cu, and more preferably at least one element selected from the group consisting of Co, Ni, Fe and Mn. For _{example, LiFePO 4, Li 3 Fe 2} (PO 4) 3, LiFeP 2 O 7 , etc. of phosphorus Santetsurui, cobalt phosphate such as LiCoPO _4, manganese phosphate such as LiMnPO _4, phosphoric acids such as LiNiPO ₄ Nickel, a part of transition metal atoms that are the main components of these lithium transition metal phosphate compounds are Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Examples include those substituted with other metals such as Nb and Si.
Among these, iron phosphates such as LiFePO ₄ , Li ₃ Fe ₂ (PO ₄ ) ₃ , and LiFeP ₂ O ₇ are preferably used because they are less likely to cause metal elution at high temperatures and charged states and are inexpensive. It is done.

The above-mentioned “LixMPO ₄ is a basic composition” includes not only the composition represented by the composition formula but also a material in which part of sites such as Fe in the crystal structure is replaced with other elements. Means that. Furthermore, it means that not only a stoichiometric composition but also a non-stoichiometric composition in which some elements are deficient or the like is included. Other elements to be substituted are preferably elements such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, and Si. When the substitution of other elements is performed, the content is preferably 0.1 mol% or more and 5 mol% or less, more preferably 0.2 mol% or more and 2.5 mol% or less.

The said positive electrode active material may be used independently and may use 2 or more types together.
Further, foreign elements may be introduced into the lithium transition metal-based compound powder of the present invention. Different elements include B, Na, Mg, Al, K, Ca, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr, Nb, Ru, Rh, Pd, Ag, In, Sn, Sb. Te, Ba, Ta, Mo, W, Re, Os, Ir, Pt, Au, Pb, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu , Bi, N, F, Cl, Br, or I. These foreign elements may be incorporated into the crystal structure of the lithium transition metal compound, or may not be incorporated into the crystal structure of the lithium transition metal compound, and may be a single element or compound on the particle surface or grain boundary. May be unevenly distributed.

(Surface coating)
Moreover, you may use what the substance of the composition different from this adhered to the surface of the said positive electrode active material. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate, and carbon.

  For example, these surface adhering substances are dissolved or suspended in a solvent, impregnated and added to the positive electrode active material, and dried. After the surface adhering substance precursor is dissolved or suspended in a solvent and impregnated and added to the positive electrode active material, It can be made to adhere to the surface of the positive electrode active material by a method of reacting by heating or the like, a method of adding to the positive electrode active material precursor and firing simultaneously. In addition, when making carbon adhere, the method of making carbonaceous adhere mechanically later in the form of activated carbon etc. can also be used, for example.

The amount of the surface adhering substance is by mass with respect to the positive electrode active material, preferably 0.1 ppm or more, more preferably 1 ppm or more, still more preferably 10 ppm or more, and the upper limit, preferably 20% or less, more preferably, as the lower limit. Is used at 10% or less, more preferably 5% or less. The surface adhering substance can suppress the oxidation reaction of the electrolyte solution on the surface of the positive electrode active material and can improve the battery life. However, when the amount of the adhering quantity is too small, the effect is not sufficiently manifested. In the case where it is too high, the resistance may increase in order to inhibit the entry and exit of lithium ions, so this composition range is preferable.
In the present invention, a material in which a material having a different composition is attached to the surface of the positive electrode active material is also referred to as “positive electrode active material”.

(shape)
Examples of the shape of the positive electrode active material particles include a lump shape, a polyhedron shape, a sphere shape, an oval sphere shape, a plate shape, a needle shape, and a column shape, which are conventionally used. It is preferable that the secondary particles have a spherical shape or an elliptical shape. In general, an electrochemical element expands and contracts as the active material in the electrode expands and contracts as it is charged and discharged. Therefore, the active material is easily damaged due to the stress or the conductive path is broken. Therefore, it is preferable that the primary particles are aggregated to form secondary particles, rather than a single particle active material having only primary particles, in order to relieve expansion and contraction stress and prevent deterioration. In addition, spherical or oval spherical particles are less oriented during molding of the electrode than plate-like equiaxed particles, so that the expansion and contraction of the electrode during charging and discharging is small, and the electrode is produced. The mixing with the conductive material is also preferable because it is easy to mix uniformly.

(Median diameter d ₅₀ )
The median diameter d ₅₀ of the positive electrode active material particles (secondary particle diameter when primary particles aggregate to form secondary particles) is preferably 0.1 μm or more, more preferably 0.5 μm or more, The upper limit is preferably 20 μm or less, more preferably 18 μm or less, still more preferably 16 μm or less, and most preferably 15 μm or less. If the lower limit is not reached, a high tap density product may not be obtained. If the upper limit is exceeded, it takes time to diffuse lithium in the particles. When a conductive material, a binder, or the like is slurried with a solvent and applied as a thin film, problems such as streaking may occur. Here, by mixing two or more kinds of the positive electrode active materials having different median diameters d ₅₀ , the filling property at the time of forming the positive electrode can be further improved.

In the present invention, the median diameter d ₅₀ is measured by a known laser diffraction / scattering particle size distribution measuring apparatus. When LA-920 manufactured by HORIBA is used as a particle size distribution meter, a 0.1% by mass sodium hexametaphosphate aqueous solution is used as a dispersion medium used for measurement, and a measurement refractive index of 1.24 is set after ultrasonic dispersion for 5 minutes. Measured.

(Average primary particle size)
When primary particles are aggregated to form secondary particles, the average primary particle diameter of the positive electrode active material is preferably 0.03 μm or more, more preferably 0.05 μm or more, and still more preferably 0.8. The upper limit is preferably 5 μm or less, more preferably 4 μm or less, still more preferably 3 μm or less, and most preferably 2 μm or less. If the above upper limit is exceeded, it is difficult to form spherical secondary particles, which adversely affects the powder filling property, or the specific surface area is greatly reduced, so that there is a high possibility that battery performance such as output characteristics will deteriorate. is there. On the other hand, when the value falls below the lower limit, there is a case where problems such as inferior reversibility of charge / discharge are usually caused because crystals are not developed.

  In the present invention, the primary particle diameter is measured by observation using a scanning electron microscope (SEM). Specifically, in a photograph at a magnification of 10000 times, the longest value of the intercept by the left and right boundary lines of the primary particles with respect to the horizontal straight line is obtained for any 50 primary particles and obtained by taking the average value. It is done.

<Configuration and manufacturing method of positive electrode>
The structure of the positive electrode will be described below. In the present invention, the positive electrode can be produced by forming a positive electrode active material layer containing a positive electrode active material and a binder on a current collector. Manufacture of the positive electrode using a positive electrode active material can be performed by a conventional method. That is, a positive electrode active material, a binder, and, if necessary, a conductive material and a thickener mixed in a dry form into a sheet form are pressure-bonded to the positive electrode current collector, or these materials are liquid media A positive electrode can be obtained by forming a positive electrode active material layer on the current collector by applying it to a positive electrode current collector and drying it as a slurry by dissolving or dispersing in a slurry.

  The content of the positive electrode active material in the positive electrode active material layer is preferably 80% by mass or more, more preferably 82% by mass or more, and particularly preferably 84% by mass or more. Moreover, an upper limit becomes like this. Preferably it is 95 mass% or less, More preferably, it is 93 mass% or less. If the content of the positive electrode active material in the positive electrode active material layer is low, the electric capacity may be insufficient. Conversely, if the content is too high, the strength of the positive electrode may be insufficient.

The positive electrode active material layer obtained by coating and drying is preferably consolidated by a hand press, a roller press or the like in order to increase the packing density of the positive electrode active material. The density of the positive electrode active material layer is preferably 1.5 g / cm ³ or more as a lower limit, more preferably 2 g / cm ³ , further preferably 2.2 g / cm ³ or more, and preferably 4.0 g as an upper limit. / Cm ³ or less,
More preferably 3.8 g / cm ³ or less, more preferably 3.6 g / cm ³ or less. If it exceeds this range, the permeability of the electrolyte solution to the vicinity of the current collector / active material interface decreases, and the charge / discharge characteristics particularly at a high current density decrease, and a high output may not be obtained. On the other hand, if it is lower, the conductivity between the active materials is lowered, the battery resistance is increased, and a high output may not be obtained.

(Conductive material)
A known conductive material can be arbitrarily used as the conductive material. Specific examples include metal materials such as copper and nickel; graphite such as natural graphite and artificial graphite (graphite); carbon black such as acetylene black; and carbon materials such as amorphous carbon such as needle coke. In addition, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio. The conductive material is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 1% by mass or more in the positive electrode active material layer, and the upper limit is usually 50% by mass or less, preferably It is used so as to contain 30% by mass or less, more preferably 15% by mass or less. If the content is lower than this range, the conductivity may be insufficient. Conversely, if the content is higher than this range, the battery capacity may decrease.

(Binder)
The binder used for manufacturing the positive electrode active material layer is not particularly limited, and in the case of a coating method, any material that can be dissolved or dispersed in a liquid medium used during electrode manufacturing may be used. Resin polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyimide, aromatic polyamide, cellulose, nitrocellulose; SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), fluorine rubber, isoprene rubber , Rubber polymers such as butadiene rubber and ethylene-propylene rubber; styrene / butadiene / styrene block copolymer or hydrogenated product thereof, EPDM (ethylene / propylene / diene terpolymer), styrene / ethylene / butadiene / Ethylene copolymer, styrene Thermoplastic elastomeric polymer such as isoprene / styrene block copolymer or hydrogenated product thereof; syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer Soft resinous polymers such as polymers; Fluoropolymers such as polyvinylidene fluoride (PVdF), polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymers; alkali metal ions (especially lithium ions) And a polymer composition having ion conductivity. In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The ratio of the binder in the positive electrode active material layer is usually 0.1% by mass or more, preferably 1% by mass or more, more preferably 3% by mass or more, and the upper limit is usually 80% by mass or less, preferably 60%. It is not more than mass%, more preferably not more than 40 mass%, most preferably not more than 10 mass%. If the ratio of the binder is too low, the positive electrode active material cannot be sufficiently retained, and the mechanical strength of the positive electrode is insufficient, which may deteriorate battery performance such as cycle characteristics. On the other hand, if it is too high, battery capacity and conductivity may be reduced.

(Thickener)
A thickener can be used normally in order to adjust the viscosity of the slurry used for manufacture of a positive electrode active material layer. In particular, when an aqueous medium is used, it is preferable to make a slurry using a thickener and a latex such as styrene-butadiene rubber (SBR). The thickener is not particularly limited, and specific examples include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios. When a thickener is further added, the ratio of the thickener to the active material is 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 0.6% by mass or more. The upper limit is 5% by mass or less, preferably 3% by mass or less, more preferably 2% by mass or less. Below this range, applicability may be significantly reduced. If it exceeds, the ratio of the active material in the positive electrode active material layer may decrease, and there may be a problem that the capacity of the battery decreases and a problem that the resistance between the positive electrode active materials increases.

(Current collector)
The material of the positive electrode current collector is not particularly limited, and a known material can be arbitrarily used. Specific examples include metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum; and carbon materials such as carbon cloth and carbon paper. Of these, metal materials, particularly aluminum, are preferred.

  Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punch metal, and foam metal in the case of a metal material. A thin film, a carbon cylinder, etc. are mentioned. Of these, metal thin films are preferred. In addition, you may form a thin film suitably in mesh shape. Although the thickness of the thin film is arbitrary, it is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and the upper limit is usually 1 mm or less, preferably 100 μm or less, more preferably 50 μm or less. If the thin film is thinner than this range, the strength required for the current collector may be insufficient. Conversely, if the thin film is thicker than this range, the handleability may be impaired.

Moreover, it is also preferable from the viewpoint of reducing the electronic contact resistance between the current collector and the positive electrode active material layer that a conductive additive is applied to the surface of the current collector. Examples of the conductive assistant include noble metals such as carbon, gold, platinum, and silver.
(Thickness of positive plate)
The thickness of the positive electrode plate is not particularly limited, but from the viewpoint of high capacity and high output, the thickness of the positive electrode active material layer obtained by subtracting the thickness of the metal foil (current collector) from the positive electrode plate is set on one side of the current collector. On the other hand, the lower limit is preferably 10 μm or more, more preferably 20 μm or more, and the upper limit is preferably 500 μm or less, more preferably 450 μm or less.

(Positive electrode surface coating)
Moreover, you may use what adhered the substance of the composition different from this to the surface of the said positive electrode plate. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate, and carbon.

5. Separator Normally, a separator is interposed between the positive electrode and the negative electrode in order to prevent a short circuit. In this case, the nonaqueous electrolytic solution of the present invention is usually used by impregnating the separator.
The material and shape of the separator are not particularly limited, and known ones can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. Among them, a resin, glass fiber, inorganic material, etc. formed of a material that is stable with respect to the non-aqueous electrolyte solution of the present invention is used, and a porous sheet or a nonwoven fabric-like material having excellent liquid retention properties is used. Is preferred.

  As materials for the resin and glass fiber separator, for example, polyolefins such as polyethylene and polypropylene, aromatic polyamides, polytetrafluoroethylene, polyethersulfone, glass filters and the like can be used. Of these, glass filters and polyolefins are preferred, and polyolefins are more preferred. These materials may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The thickness of the separator is arbitrary, but is usually 1 μm or more, preferably 5 μm or more, more preferably 8 μm or more, and usually 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less. If the separator is too thin than the above range, the insulating properties and mechanical strength may decrease. On the other hand, if it is thicker than the above range, not only the battery performance such as the rate characteristic may be lowered, but also the energy density of the whole non-aqueous electrolyte secondary battery may be lowered.

  Furthermore, when using a porous material such as a porous sheet or nonwoven fabric as the separator, the porosity of the separator is arbitrary, but is usually 20% or more, preferably 35% or more, more preferably 45% or more, Further, it is usually 90% or less, preferably 85% or less, and more preferably 75% or less. If the porosity is too smaller than the above range, the membrane resistance tends to increase and the rate characteristics tend to deteriorate. Moreover, when larger than the said range, it exists in the tendency for the mechanical strength of a separator to fall and for insulation to fall.

Moreover, although the average pore diameter of a separator is also arbitrary, it is 0.5 micrometer or less normally, 0.2 micrometer or less is preferable, and it is 0.05 micrometer or more normally. If the average pore diameter exceeds the above range, a short circuit tends to occur. On the other hand, below the above range, the film resistance may increase and the rate characteristics may deteriorate.
On the other hand, as inorganic materials, for example, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate are used. Used.

  As the form, a thin film shape such as a non-woven fabric, a woven fabric, or a microporous film is used. In the thin film shape, those having a pore diameter of 0.01 to 1 μm and a thickness of 5 to 50 μm are preferably used. In addition to the above-mentioned independent thin film shape, a separator formed by forming a composite porous layer containing the inorganic particles on the surface layer of the positive electrode and / or the negative electrode using a resin binder can be used. For example, a porous layer may be formed by using alumina particles having a 90% particle size of less than 1 μm on both surfaces of the positive electrode and using a fluororesin as a binder.

  The Gurley value of the separator represents the difficulty of air passage in the film thickness direction, and is expressed as the number of seconds required for 100 ml of air to pass through the film. Means that it is difficult to get through. That is, a smaller value means better communication in the thickness direction of the film, and a larger value means lower communication in the thickness direction of the film. Communication is the degree of connection of holes in the film thickness direction. If the Gurley value of the separator of the present invention is low, it can be used for various purposes. For example, when used as a separator for a non-aqueous lithium secondary battery, a low Gurley value means that lithium ions can be easily transferred and is preferable because of excellent battery performance. Although the Gurley value of a separator is arbitrary, Preferably it is 10-1000 second / 100ml, More preferably, it is 15-800 second / 100ml, More preferably, it is 20-500 second / 100ml. If the Gurley value is 1000 seconds / 100 ml or less, the electrical resistance is substantially low, which is preferable as a separator.

6). Battery design <Electrode group>
The electrode group has a laminated structure in which the positive electrode plate and the negative electrode plate are interposed through the separator, and a structure in which the positive electrode plate and the negative electrode plate are wound in a spiral shape through the separator. Either is acceptable. The ratio of the volume of the electrode group to the internal volume of the battery (hereinafter referred to as the electrode group occupation ratio) is usually 40% or more, preferably 50% or more, and usually 90% or less, preferably 80% or less. .

  When the electrode group occupancy is below the above range, the battery capacity decreases. Also, if the above range is exceeded, the void space is small, the battery expands, and the member expands or the vapor pressure of the electrolyte liquid component increases and the internal pressure rises. In some cases, the gas release valve that lowers various characteristics such as storage at high temperature and the like, or releases the internal pressure to the outside is activated.

<Exterior case>
The material of the outer case is not particularly limited as long as it is a substance that is stable with respect to the non-aqueous electrolyte used. Specifically, a nickel-plated steel plate, stainless steel, aluminum, an aluminum alloy, a metal such as a magnesium alloy, or a laminated film (laminate film) of a resin and an aluminum foil is used. From the viewpoint of weight reduction, an aluminum or aluminum alloy metal or a laminate film is preferably used.

  In an exterior case using metals, the metal is welded together by laser welding, resistance welding, or ultrasonic welding to form a sealed sealed structure, or a caulking structure using the above metals via a resin gasket. Things. Examples of the outer case using the laminate film include a case where a resin-sealed structure is formed by heat-sealing resin layers. In order to improve sealing performance, a resin different from the resin used for the laminate film may be interposed between the resin layers. In particular, when a resin layer is heat-sealed through a current collecting terminal to form a sealed structure, a metal and a resin are joined, so that a resin having a polar group or a modified group having a polar group introduced as an intervening resin is used. Resins are preferably used.

<Protective element>
As a protective element, PTC (Positive Temperature Coefficient), thermal fuse, thermistor, whose resistance increases when abnormal heat or excessive current flows, cut off current flowing in the circuit due to sudden rise in battery internal pressure or internal temperature at abnormal heat generation A valve (current cutoff valve) or the like can be used. It is preferable to select a protective element that does not operate under normal use at a high current, and it is more preferable that the protective element is designed so as not to cause abnormal heat generation or thermal runaway even without the protective element.

<Exterior body>
The non-aqueous electrolyte secondary battery of the present invention is usually configured by housing the non-aqueous electrolyte, the negative electrode, the positive electrode, the separator, and the like in an exterior body. This exterior body is not particularly limited, and any known one can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. Specifically, the material of the exterior body is arbitrary, but usually, for example, nickel-plated iron, stainless steel, aluminum or an alloy thereof, nickel, titanium, or the like is used.

The shape of the exterior body is also arbitrary, and may be any of a cylindrical shape, a square shape, a laminate shape, a coin shape, a large size, and the like.
7). Battery Performance The battery obtained in the present invention can be used without particular limitation, but can be preferably used for a battery with a higher voltage or a higher capacity.

For example, in the case of a lithium ion secondary battery, the increase in voltage is usually 4.25 V or more, preferably 4.3 or more.
The increase in capacity is usually 2600 mAh or more, preferably 2800 mAh or more, more preferably 3000 mAh or more in the case of an 18650 type battery, for example.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.
The compound of the general formula (1) used in this example was synthesized by the following method.
[Compound α]
The raw material 1) was synthesized according to the method of non-patent literature (Journal of Organic Chemistry, 56 (3), 1083-1088 (1991)). Next, compound α was obtained by a method according to non-patent literature (European journal of organic chemistry, 2009 (20), 2836-2844).

[Compound β]
Under a nitrogen stream, the raw material 1) was dissolved in methylene chloride, and the methylene chloride solution of the raw material 3) was added dropwise. After stirring at room temperature for 3 hours, the reaction was stopped by adding water, and the organic layer was washed with saturated aqueous sodium bicarbonate and water, dried over magnesium sulfate, and then the solvent was removed under reduced pressure to obtain Intermediate 1). This intermediate 1) was dissolved in acetonitrile, and an aqueous solution in which a catalytic amount of ruthenium chloride was dissolved and sodium periodate were sequentially added with ice cooling, followed by stirring for 1 hour. Diethyl ether and saturated aqueous sodium hydrogen carbonate were added, and the mixture was extracted into an organic layer. After drying with sodium sulfate, the product was purified by silica gel column chromatography to obtain compound β.

[Compound γ]
Under a nitrogen stream, the tetrahydrofuran raw material 1) was dissolved, triethylamine was added to make it basic, and then a tetrahydrofuran solution of the raw material 4) was dropped. Thereafter, the mixture was stirred at room temperature for 2 hours, and the precipitated white powder was filtered off, and then the solvent was removed under reduced pressure to obtain Compound γ.

<Example A>
Examples 1-3
[Production of negative electrode]
A spheroidized natural graphite mixture having the following physical properties was used as the negative electrode active material. Specifically, the spherical natural carbon whose negative electrode active material measured by the above method has a Raman R value of 0.21 and a d value (interlayer distance) of a lattice plane (002 plane) of 0.336 nm. A material mixture was used. Here, as the spheroidized natural carbonaceous material mixture, a mixture obtained by mixing spheroidized natural graphite particles and spheroidized natural graphite particles at 1000 ° C. in a mass ratio of 1: 1 was used.

98 parts by mass of the negative electrode active material, 100 parts by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of sodium carboxymethylcellulose) and an aqueous dispersion of styrene-butadiene rubber (styrene 1 part by mass of a butadiene rubber concentration of 50% by mass was added and mixed with a disperser to form a slurry. The obtained slurry was applied to a copper foil having a thickness of 18 μm, dried, rolled to an electrode density of 1.7 g / cm ³ with a press, and the cut out was used as the negative electrode.

[Production of positive electrode]
90% by mass of LiCoO ₂ as a positive electrode active material, 5% by mass of acetylene black as a conductive material, and 5% by mass of polyvinylidene fluoride (PVdF) as a binder were mixed in an N-methylpyrrolidone solvent. And slurried. The obtained slurry was applied to an aluminum foil having a thickness of 15 μm, dried, rolled with a press, and the cut out was used as a positive electrode.

[Preparation of electrolyte]
Under a dry argon atmosphere, a basic electrolyte solution was prepared by dissolving LiPF ₆ in a mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) (volume ratio 30:70) to a ratio of 1 mol / L. . A compound described in Table 1 was mixed with this basic electrolytic solution and used as an electrolytic solution.

[Production of lithium secondary battery]
The positive electrode, the negative electrode, and the polyethylene separator were laminated in the order of the negative electrode, the separator, and the positive electrode to prepare a battery element. The battery element was inserted into a bag made of a laminate film in which both surfaces of aluminum (thickness: 40 μm) were coated with a resin layer while projecting positive and negative terminals, and each of the electrolyte solutions shown in Table 1 was placed in the bag. And sealed in a vacuum to produce a sheet-like battery.

[Run-in operation]
The lithium secondary battery produced as described above was subjected to a break-in operation at a constant current corresponding to 0.2 C at 25 ° C. in a state where the lithium secondary battery was sandwiched between glass plates in order to improve the adhesion between the electrodes. A battery that has been subjected to a break-in operation is charged at a constant current-constant voltage charge (hereinafter referred to as “CCCV charge” as appropriate) (0.05 C cut) at a current corresponding to 0.2 C at 25 ° C., and then to 0.2 C. A constant current discharge was performed at a corresponding current to determine an initial discharge capacity. Here, 1C represents a current value that discharges the reference capacity of the battery in one hour, 5C represents a current value that is five times that of the battery, and 0.2C represents a current value that is 1/5 of the current value.

[Evaluation of cycle characteristics]
The lithium secondary battery that has been subjected to the break-in operation was charged at 45 ° C. with a constant current of 0.5 C, and then discharged with a constant current of 0.5 C, and 100 cycles were performed. The capacity retention rate was calculated from the formula of (discharge capacity at the 100th cycle) ÷ (discharge capacity at the first cycle) × 100.

[Evaluation of high-temperature storage characteristics]
The battery after the break-in operation was charged at a constant current-constant voltage (0.05 C cut) at a current corresponding to 0.2 C at 25 ° C., and then stored at 85 ° C. for 24 hours. After the battery was cooled to room temperature, it was immersed in an ethanol bath to measure the volume, and the amount of gas generated from the volume change before and after high temperature storage was determined.

Example 4
Assembling the battery using the same positive electrode and electrolyte (including the compound) as in Example 1 except that the composite of spheroidized natural graphite described below and a mixture of spheroidized natural graphite and a mixture of spheroidized natural graphite was used as the negative electrode active material, Similarly, the battery characteristics were obtained. Specifically, in the spherical natural graphite, the Raman R value of the negative electrode active material measured by the above method is 0.22, and the d value (interlayer distance) of the lattice plane (002 plane) is 0.336 nm. A mixture of carbon-coated composite and spheronized natural graphite was used.

Here, for the composite obtained by coating spheroidized natural graphite with carbon, a material obtained by coating the carbon precursor with spheroidized natural graphite so as to be 3% by mass (coverage) after firing, and firing at 1300 ° C. was used. . Furthermore, a mixture obtained by mixing the carbon-coated composite with spheroidized natural graphite at a mass ratio of 1: 1 was used as the negative electrode active material.
Using the negative electrode active material, a negative electrode was prepared in the same manner as described in Example 1.
A battery was assembled using the same positive electrode as in Example 1 except that the negative electrode and the electrolytic solution shown in Table 1 were used, and the battery characteristics were similarly determined.

Example 5
Example 1 except that a composite of spheroidized natural graphite described below coated with graphite and a spheroidized natural graphite having a rhombohedral rate of 21% and a spheroidized natural graphite having a rhombohedral rate of 21% was used as the negative electrode active material. A battery was assembled using the same positive electrode and electrolyte solution (including the compound) as above, and the battery characteristics were similarly determined. Specifically, in the spherical natural graphite, the Raman R value of the negative electrode active material measured by the above method is 0.17, and the d value (interlayer distance) of the lattice plane (002 plane) is 0.336 nm. A mixture of a composite coated with graphite and spheroidized natural graphite was used.

Here, for the composite obtained by coating spheroidized natural graphite with graphite, a material obtained by coating the carbon precursor with spheroidized natural graphite so as to be 15% by mass (coverage) after firing and firing at 3000 ° C. was used. . Further, a mixture obtained by mixing spheroidized natural graphite in a mass ratio of 6: 4 to the graphite-coated composite was used as the negative electrode active material.
Using the negative electrode active material, a negative electrode was prepared in the same manner as described in Example 1.
A battery was assembled using the same positive electrode as in Example 1 except that the negative electrode and the electrolytic solution described in Table 1 were used, and the battery characteristics were similarly determined.

Comparative Examples 1 and 2
A battery was assembled using the same negative electrode and positive electrode as in Example 1 except that the compounds contained in the electrolytic solution shown in Table 1 were changed, and battery characteristics were similarly determined.
Table 1 shows the powder physical properties of the negative electrode active materials obtained in the above Examples and Comparative Examples, the compounds contained in the electrolyte, and the battery characteristics.

As is clear from Table 1, in a battery using a negative electrode whose Raman value is within the range of the present invention, when a nonaqueous electrolytic solution containing a compound of the general formula (1) is used (Examples 1 to 5) Compared with the case where the non-aqueous electrolyte not containing the compound of the general formula (1) is used (Comparative Examples 1 and 2), the cycle capacity retention rate and the gas generation amount suppression during high temperature storage are excellent. Moreover, even if it is a case where compounds other than general formula (1) are introduce | transduced with compounds other than general formula (1), it turns out that it is excellent in the said battery durability. The reason for exhibiting such an excellent cycle capacity retention rate and a low gas generation amount is that the compound of the general formula (1) in the non-aqueous electrolyte at the time of charge / discharge used a negative electrode active material having a specific Raman value. It is presumed that an extremely stable negative electrode surface protective layer capable of preventing deterioration of battery characteristics is formed on the negative electrode surface.

<Example B>
Examples 6-9
[Production of negative electrode]
As the negative electrode active material, a composite in which spheroidized natural graphite described below was coated with carbon was used. Specifically, carbon is applied to spheroidized natural graphite having a Raman R value of 0.32 measured by the above method and a d value (interlayer distance) of the lattice plane (002 plane) of 0.3355 nm. The coated composite was used. Here, for the composite obtained by coating spheroidized natural graphite with carbon, a material obtained by coating the carbon precursor with spheroidized natural graphite so as to be 3% by mass (coverage) after firing, and firing at 1100 ° C. was used. .

98 parts by mass of the negative electrode active material, 100 parts by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of sodium carboxymethylcellulose) and an aqueous dispersion of styrene-butadiene rubber (styrene 1 part by mass of a butadiene rubber concentration of 50% by mass was added and mixed with a disperser to form a slurry. The obtained slurry was applied to a copper foil having a thickness of 18 μm, dried, rolled to an electrode density of 1.45 g / cm ³ with a press, and the cut out was used as the negative electrode.

[Production of positive electrode]
90% by mass of Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ as a positive electrode active material, 5% by mass of acetylene black as a conductive material, and polyvinylidene fluoride (PVdF) 5 as a binder % By mass was mixed in N-methylpyrrolidone solvent to make a slurry. The obtained slurry was applied to an aluminum foil having a thickness of 15 μm, dried, and rolled with a press to be used as a positive electrode.

[Preparation of electrolyte]
Under a dry argon atmosphere, a basic electrolyte solution was prepared by dissolving LiPF ₆ dried in a mixture of ethylene carbonate, dimethyl carbonate and diethyl carbonate (volume ratio 30:30:40) to a ratio of 1 mol / L. The basic electrolyte solution was mixed with a compound shown in Table 2 to obtain an electrolyte solution.

[Production of lithium secondary battery]
A sheet-like battery was produced in the same manner as in Example 1 using the above positive electrode, negative electrode, and electrolytic solution.
[Evaluation of initial discharge capacity]
The lithium secondary battery was conditioned with a constant current corresponding to 0.2 C at 25 ° C. in a state of being sandwiched between glass plates in order to improve the adhesion between the electrodes. A battery that has been conditioned is charged at a constant current-constant voltage (0.05 C cut) at a current corresponding to 0.2 C at 25 ° C., and then a constant current discharge is performed at a current corresponding to 0.2 C. The initial discharge capacity was determined.

[Evaluation of cycle characteristics]
The lithium secondary battery that had been subjected to a break-in operation was charged at 60 ° C. with a constant current of 2 C, and then discharged with a constant current of 2 C, and 500 cycles were performed. The discharge capacity retention rate was determined from the formula of (discharge capacity at 500th cycle) ÷ (discharge capacity at the first cycle) × 100.

Reference Example 1 and Comparative Example 3
A negative electrode produced by the same method as in Example 6 was used except that spheroidized graphite particles having the following physical properties were used as the negative electrode active material. Specifically, graphite particles having a Raman R value of 0.04 measured by the above method and a d value (interlayer distance) of the lattice plane (002 plane) of 0.3354 nm were used.

A battery was assembled using the same positive electrode as in Example 6 except that the above negative electrode and the electrolytic solution shown in Table 2 were used, and the battery characteristics were similarly determined.
Comparative Examples 4-6
A battery was assembled using the same negative electrode and positive electrode as in Example 6 except that the electrolytic solution shown in Table 2 was used, and the battery characteristics were similarly determined.
Table 2 shows the powder physical properties of the negative electrode active materials obtained in the above Examples and Comparative Examples, the compounds contained in the electrolytic solution, and the battery characteristics.

As is apparent from Table 2, in a battery using a negative electrode whose Raman value is within the range of the present invention, when a nonaqueous electrolytic solution containing the compound of the general formula (1) is used (Examples 6 to 9) Compared with the case where the Raman value is not within the range of the present invention (Reference Example 1, Comparative Example 3) and the case where a non-aqueous electrolyte not containing the compound of the general formula (1) is used (Comparative Examples 4 to 6). Excellent cycle capacity maintenance rate.

Even in the case of a compound having a carbon-carbon triple bond site as in the general formula (1), a chain compound having a carbon-carbon triple bond bonded as described in Patent Document 3 (Comparative Example 6). Even if a carbonaceous material having a Raman R value of 0.1 or more is used, such an effect is not confirmed, and the carbon-carbon triple bond of the general formula (1) is bonded to the ring structure by a single bond It can be understood that this is a specific characteristic confirmed only by the compound. Furthermore, even when a positive electrode active material of a different type from the positive electrode active material used in Example (A) is used, the effect of the present invention is maintained. The reason for exhibiting such an excellent cycle capacity retention rate is that the compound of the general formula (1) in the non-aqueous electrolyte during charging and discharging is on the negative electrode surface using a negative electrode active material having a specific Raman value. It is presumed that an extremely stable negative electrode surface protective layer capable of preventing deterioration of battery characteristics is formed.

<Example C>
Examples 10 to 12, Comparative Examples 7 and 8
[Production of negative electrode]
As the negative electrode active material, a composite in which spheroidized natural graphite described below was coated with carbon was used. Specifically, carbon is applied to spheroidized natural graphite having a Raman R value of 0.32 measured by the above method and a d value (interlayer distance) of the lattice plane (002 plane) of 0.3355 nm. The coated composite was used. Here, for the composite obtained by coating spheroidized natural graphite with carbon, a material obtained by coating the carbon precursor with spheroidized natural graphite so as to be 3% by mass (coverage) after firing, and firing at 1100 ° C. was used. .

98 parts by mass of the negative electrode active material, 100 parts by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of sodium carboxymethylcellulose) and an aqueous dispersion of styrene-butadiene rubber (styrene 1 part by mass of a butadiene rubber concentration of 50% by mass was added and mixed with a disperser to form a slurry. The obtained slurry was applied to a copper foil having a thickness of 18 μm, dried, rolled with a press machine to an electrode density of 1.5 g / cm ³ , and the cut out was used as a negative electrode.

[Production of positive electrode]
90% by mass of Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ as a positive electrode active material, 5% by mass of acetylene black as a conductive material, and polyvinylidene fluoride (PVdF) 5 as a binder % By mass was mixed in N-methylpyrrolidone solvent to make a slurry. The obtained slurry was applied to an aluminum foil having a thickness of 15 μm, dried, and rolled with a press to be used as a positive electrode.

[Preparation of electrolyte]
In a dry argon atmosphere, a basic electrolyte solution was prepared by dissolving LiPF ₆ in a mixture of monofluoroethylene carbonate, dimethyl carbonate and diethyl carbonate (volume ratio 30:30:40) to a ratio of 1 mol / L. did. The basic electrolyte solution was mixed with the compounds shown in Table 3 to obtain an electrolyte solution.

[Production of lithium secondary battery]
A sheet-like battery was produced in the same manner as in Example 1 using the above positive electrode, negative electrode, and electrolytic solution.
[Evaluation of initial discharge capacity]
The lithium secondary battery was conditioned with a constant current corresponding to 0.2 C at 25 ° C. in a state of being sandwiched between glass plates in order to improve the adhesion between the electrodes. A battery that has been conditioned is charged at a constant current-constant voltage (0.05 C cut) at a current corresponding to 0.2 C at 25 ° C., and then a constant current discharge is performed at a current corresponding to 0.2 C. The initial discharge capacity was determined.

[Evaluation of cycle characteristics]
The lithium secondary battery that had been subjected to a break-in operation was charged at a constant current of 2C at 60 ° C. and then discharged at a constant current of 2C. The discharge capacity retention rate was determined from the formula of (discharge capacity at 500th cycle) ÷ (discharge capacity at the first cycle) × 100.

  A sheet-like lithium secondary battery was prepared in the same manner as in Example 1 except that the negative electrode and the positive electrode and the compounds contained in the electrolytic solution shown in Table 3 were changed, and battery characteristics were determined.

As is clear from Table 3, in the battery using the negative electrode whose Raman value is within the range of the present invention, the non-aqueous electrolyte solution containing the compound of the general formula (1) (Examples 10 to 12) (1)
Compared to batteries (Comparative Examples 7 and 8) using a non-aqueous electrolyte solution containing the above compound, the high temperature cycle capacity retention rate is excellent. As described above, any compound represented by the general formula (1) exhibits a characteristic effect on battery durability regardless of which compound is used. However, even in the case of a compound having a multiple bond site outside the ring as in the general formula (1), the compound of Comparative Example 7 having a carbon-carbon double bond outside the ring is assumed to have a Raman value of the present invention. Even if the negative electrode within the range is used, the durability improvement effect is greatly inferior to Examples 10-12. The reason for exhibiting such an excellent cycle capacity retention rate is that the compound of the general formula (1) in the non-aqueous electrolyte during charging / discharging is
It is estimated that an effective and extremely stable negative electrode surface protective layer capable of preventing deterioration of battery characteristics is formed on the negative electrode surface using a negative electrode active material having a specific Raman value. It can also be seen that the effects of the present invention are maintained even when the battery voltage is higher than in Examples (A) and (B).

<Example D>
Examples 13 to 16, Comparative Examples 9 and 10
[Production of negative electrode]
As the negative electrode active material, a composite in which spheroidized natural graphite described below was coated with carbon was used. Specifically, carbon is applied to spheroidized natural graphite having a Raman R value of 0.32 measured by the above method and a d value (interlayer distance) of the lattice plane (002 plane) of 0.3355 nm. The coated composite was used. Here, for the composite obtained by coating spheroidized natural graphite with carbon, a material obtained by coating the carbon precursor with spheroidized natural graphite so as to be 3% by mass (coverage) after firing, and firing at 1300 ° C. was used. .

98 parts by mass of the negative electrode active material, 100 parts by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of sodium carboxymethylcellulose) and an aqueous dispersion of styrene-butadiene rubber (styrene 1 part by mass of a butadiene rubber concentration of 50% by mass was added and mixed with a disperser to form a slurry. The obtained slurry was applied to a copper foil having a thickness of 18 μm, dried, rolled with a press machine to an electrode density of 1.5 g / cm ³ , and the cut out was used as a negative electrode.

[Production of positive electrode]
90% by mass of Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ as a positive electrode active material, 5% by mass of acetylene black as a conductive material, and polyvinylidene fluoride (PVdF) 5 as a binder % By mass was mixed in N-methylpyrrolidone solvent to make a slurry. The obtained slurry was applied to a 15 μm-thick aluminum foil previously coated with a conductive additive, dried, and rolled with a press to be used as the positive electrode.

[Preparation of electrolyte]
Under a dry argon atmosphere, a basic electrolyte solution was prepared by dissolving LiPF ₆ dried in a mixture of ethylene carbonate, dimethyl carbonate and diethyl carbonate (volume ratio 30:30:40) to a ratio of 1 mol / L. The basic electrolyte solution was mixed with the compounds described in Table 4 to obtain an electrolyte solution.

[Production of lithium secondary battery]
A sheet-like battery was produced in the same manner as in Example 1 using the above positive electrode, negative electrode, and electrolytic solution.
[Evaluation of initial discharge capacity]
The lithium secondary battery was conditioned with a constant current corresponding to 0.2 C at 25 ° C. in a state of being sandwiched between glass plates in order to improve the adhesion between the electrodes. A battery that has been conditioned is charged at a constant current-constant voltage (0.05 C cut) at a current corresponding to 0.2 C at 25 ° C., and then a constant current discharge is performed at a current corresponding to 0.2 C. The initial discharge capacity was determined.

[Evaluation of high-temperature storage characteristics]
The lithium secondary battery that had been conditioned was charged at a constant current-constant voltage (0.05 C cut) at a current corresponding to 0.2 C, and then stored at 75 ° C. for 120 hours. After cooling the battery to room temperature, discharge at a constant current at a current equivalent to 0.2 C to obtain the discharge capacity, and the capacity maintenance rate from the formula of (discharge capacity after storage) ÷ (initial discharge capacity) × 100 Asked. The results are shown in Table 4.

As is clear from Table 4, in the battery using the negative electrode whose Raman value is within the range of the present invention, the non-aqueous electrolyte solutions (Examples 13 to 16) containing the compound of the general formula (1) (1)
Compared to a battery (Comparative Examples 9 and 10) using a non-aqueous electrolyte solution containing the above compound, the high-temperature storage capacity retention rate is excellent. The reason for exhibiting such an excellent cycle capacity retention rate is that the compound of the general formula (1) in the non-aqueous electrolyte during charging and discharging is on the negative electrode surface using a negative electrode active material having a specific Raman value. It is presumed that an effective and extremely stable negative electrode surface protective layer capable of preventing deterioration of battery characteristics is formed.

<Example E>
Example 17, Comparative Examples 13 and 14
[Production of negative electrode]
As the negative electrode active material, a composite in which spheroidized natural graphite described below was coated with carbon was used. Specifically, carbon is applied to spheroidized natural graphite having a Raman R value of 0.32 measured by the above method and a d value (interlayer distance) of the lattice plane (002 plane) of 0.3355 nm. The coated composite was used. Here, for the composite obtained by coating spheroidized natural graphite with carbon, a material obtained by coating the carbon precursor with spheroidized natural graphite so as to be 3% by mass (coverage) after firing, and firing at 1300 ° C. was used. .

98 parts by mass of the negative electrode active material, 100 parts by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of sodium carboxymethylcellulose) and an aqueous dispersion of styrene-butadiene rubber (styrene 1 part by mass of a butadiene rubber concentration of 50% by mass was added and mixed with a disperser to form a slurry. The obtained slurry was applied to a copper foil having a thickness of 18 μm, dried, rolled with a press machine to an electrode density of 1.5 g / cm ³ , and the cut out was used as a negative electrode.

[Production of positive electrode]
90% by mass of Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ as a positive electrode active material, 5% by mass of acetylene black as a conductive material, and polyvinylidene fluoride (PVdF) 5 as a binder % By mass was mixed in N-methylpyrrolidone solvent to make a slurry. The obtained slurry was applied to a 15 μm-thick aluminum foil previously coated with a conductive additive, dried, and rolled with a press to be used as the positive electrode.

[Preparation of electrolyte]
Under a dry argon atmosphere, a basic electrolyte solution was prepared by dissolving LiPF ₆ dried in a mixture of ethylene carbonate, dimethyl carbonate and diethyl carbonate (volume ratio 30:30:40) to a ratio of 1 mol / L. The basic electrolyte solution was mixed with the compounds shown in Table 3 to obtain an electrolyte solution.

[Production of lithium secondary battery]
A sheet-like battery was produced in the same manner as in Example 1 using the above positive electrode, negative electrode, and electrolytic solution.
[Evaluation of initial discharge capacity]
The lithium secondary battery was conditioned with a constant current corresponding to 0.2 C at 25 ° C. in a state of being sandwiched between glass plates in order to improve the adhesion between the electrodes. A battery that has been conditioned is charged at a constant current-constant voltage (0.05 C cut) at a current corresponding to 0.2 C at 25 ° C., and then a constant current discharge is performed at a current corresponding to 0.2 C. The initial discharge capacity was determined.

[Evaluation of cycle characteristics]
The battery that was subjected to the running-in operation was charged at a constant current of 2C at 60 ° C. and then discharged at a constant current of 2C. The discharge capacity retention ratio was calculated from the formula of (discharge capacity at 300th cycle) ÷ (discharge capacity at the first cycle) × 100. The evaluation results are shown in Table 5.

Example 18, Comparative Examples 11, 12, 15
[Preparation of electrolyte]
In a dry argon atmosphere, a basic electrolyte solution was prepared by dissolving LiPF ₆ in a mixture of monofluoroethylene carbonate, dimethyl carbonate and diethyl carbonate (volume ratio 30:30:40) to a ratio of 1 mol / L. did. The compound was mixed with the basic electrolyte at a ratio shown in Table 3.

[Production of lithium secondary battery]
A sheet-like battery was produced by the same method as in Example 15 using the above positive electrode, negative electrode, and electrolytic solution, and battery characteristics were evaluated.

As is clear from Table 5, in the battery using the negative electrode whose Raman value is within the range of the present invention, the non-aqueous electrolyte solution containing the compound of the general formula (1) (Examples 17 and 18) has the general formula (1)
Compared to batteries (Comparative Examples 11 to 15) using a non-aqueous electrolyte solution containing the above compound, the high temperature cycle capacity retention rate is excellent. However, a compound having a double bond in the ring (Comparative Example 11) or a compound having a multiple bond site outside the ring as in the general formula (1) has a carbon-carbon double bond outside the ring. Even if it is a compound having a carbon-carbon triple bond site as in the general formula (1) or a compound having a carbon-carbon triple bond described in Patent Document 3 In the case of the compound (Comparative Example 14), such an effect is not confirmed even when used together with a carbonaceous material having a Raman R value of 0.1 or more, and the carbon-carbon triple bond is bonded to the ring structure by a single bond. It can be understood that this is a specific feature confirmed only by the compound of the general formula (1). The reason for exhibiting such an excellent cycle capacity retention rate is that the compound of the general formula (1) in the non-aqueous electrolyte during charging and discharging is on the negative electrode surface using a negative electrode active material having a specific Raman value. It is presumed that an extremely stable negative electrode surface protective layer capable of preventing deterioration of battery characteristics is formed. Moreover, even if it is a state still higher than the battery voltage of Example (A)-(D), the effect of this invention is maintained.

  According to the combination of the negative electrode and the non-aqueous electrolyte solution of the present invention, the non-aqueous electrolyte secondary battery has a high capacity retention rate and is useful even after a durability test such as a high-temperature storage test or a cycle test. Therefore, the negative electrode active material, the non-aqueous electrolyte solution, and the non-non-aqueous electrolyte secondary battery using the negative electrode active material of the present invention can be used for various known applications. Specific examples include notebook computers, pen input computers, mobile computers, electronic book players, mobile phones, mobile faxes, mobile copy, mobile printers, headphone stereos, video movies, LCD TVs, handy cleaners, portable CDs, minidiscs, etc. , Walkie Talkie, Electronic Notebook, Calculator, Memory Card, Portable Tape Recorder, Radio, Backup Power Supply, Motor, Automobile, Motorcycle, Motorbike, Bicycle, Lighting Equipment, Toy, Game Equipment, Clock, Electric Tool, Strobe, Camera, Load Examples include leveling power sources and natural energy storage power sources.

Claims (7)

A non-aqueous electrolyte secondary battery comprising a non-aqueous electrolyte solution containing a lithium salt and a non-aqueous solvent for dissolving the lithium salt, a negative electrode capable of occluding and releasing lithium ions, and a positive electrode,
The negative electrode, the Raman R value, defined as the ratio of the peak intensity of 1360 cm ^-1 to the peak intensity of 1580 cm ^-1 in the argon ion laser Raman spectroscopy to contain at least one or more carbonaceous material is 0.1 or more Including negative electrode active material,
And the said non-aqueous electrolyte solution contains the compound represented by following General formula (2) , The non-aqueous electrolyte secondary battery characterized by the above-mentioned.

( Y represents C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ³ , where R ² may have a functional group. It is a hydrocarbon group of the number 1 to 20. R ³ is Li,
NR ⁴ ₄ or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group. R ⁴ is
It is a C1-C20 hydrocarbon group which may have a functional group, and may be the same or different from each other. )   The non-aqueous electrolyte secondary battery according to claim 1, wherein the carbonaceous material has an interlayer distance d002 of 0.335 nm or more and 0.339 nm or less.   The carbonaceous material includes at least one selected from the group consisting of a carbonaceous material obtained by coating carbon with nuclear graphite, a carbonaceous material obtained by coating graphite with nuclear graphite, and a natural carbonaceous material. Item 3. The nonaqueous electrolyte secondary battery according to Item 1 or 2. The compound represented by the general formula (2) is at least one of compounds represented by the following formulas (4) to (9), according to any one of claims 1 to 3. The non-aqueous electrolyte secondary battery described.

The non-aqueous electrolyte is: (A) Li _α XO _n F _m (X = any element of Groups 13, 15, 16 in the second or third period of the periodic table, α = 1-2, n = 1-3) The non-aqueous electrolyte secondary battery according to any one of claims 1 to 4, comprising a compound represented by: m = 1 to 2). The non-aqueous electrolyte secondary battery according to any one of claims 1 to 5, wherein the non-aqueous electrolyte contains (B) an oxalate compound represented by the following general formula (3). .

(In the general formula (3), A represents an alkali metal, M is a transition metal, a group 13, 14 or 15 element of the periodic table, b is 1 to 3, m is 1 to 3, and n is 0 to 6, q represents 0 or 1, respectively, and R ⁵ represents alkylene having 1 to 10 carbons, halogenated alkylene having 1 to 10 carbons, arylene having 6 to 20 carbons, or 6 to 20 carbons. A halogenated arylene (these alkylene and arylene may have a substituent or a hetero atom in the structure thereof, and m R ^{5 s} may be bonded to each other), and R ⁶ is , Halogen, alkyl having 1 to 10 carbons, alkyl halide having 1 to 10 carbons, aryl having 6 to 20 carbons, halogenated aryl having 6 to 20 carbons, or X ³ R ⁷ (these alkyls and aryls) Is The structure may have a substituent or a heteroatom, and n R ^{6 s} may be bonded to each other to form a ring.), X ¹ , X ² , X ³ Is O, S, or NR ⁸ , and R ⁷ and R ⁸ are each independently hydrogen, alkyl having 1 to 10 carbons, halogenated alkyl having 1 to 10 carbons, or 6 to 20 carbons Aryl, or an aryl halide having 6 to 20 carbon atoms (these alkyl and aryl may have a substituent or a hetero atom in the structure, or a plurality of R ⁷ and R ⁸ are bonded to each other) And may form a ring.))   The non-aqueous electrolyte according to any one of claims 1 to 6, wherein the non-aqueous electrolyte contains (C) a carbonate having at least one of a carbon-carbon unsaturated bond or a fluorine atom. Electrolyte secondary battery.