JP2015022847A - Method for manufacturing negative electrode for nonaqueous electrolyte secondary battery, negative electrode manufactured by the method, and nonaqueous electrolyte secondary battery using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method preventing a surfactant from remaining in an electrode to be decomposed during the operation of a nonaqueous electrolyte secondary battery.SOLUTION: A negative electrode for a nonaqueous electrolyte secondary battery is manufactured using a negative electrode paste containing: an electrode active material, such as lithium titanate, in which detachment and insertion of lithium ions proceed at 0.3 V(vs.Li/Li) or more and 2.0 V(vs.Li/Li) or less; and one or both of kiton represented by the following formula (1) and fluorine-substituted dialkyl diol. (Rand Rrepresent a 1-10C alkyl group containing at least one fluorine atom, and Rand Rmay be the same or different from each other).

Description

  The present invention relates to a method for producing a negative electrode for a nonaqueous electrolyte secondary battery, a negative electrode for a nonaqueous electrolyte secondary battery produced by the method, and a nonaqueous electrolyte secondary battery using the same.

  In recent years, non-aqueous electrolyte secondary batteries have been actively researched and developed for portable devices, hybrid vehicles, electric vehicles, and household power storage applications. The nonaqueous electrolyte secondary battery used in these fields needs to be designed so that the energy density per unit mass or volume of the electrode is maximized in order to limit installation location and reduce costs. For this reason, it is necessary to fully consider ensuring the adhesion of the electrode active material to the current collector.

However, if the electrode active material particles are aggregated when the electrode active material is attached to the current collector, the adhesion of the electrode active material to the current collector deteriorates, and the electrode material is peeled off from the current collector. There is a risk. When peeling occurs, there is a problem that the capacity of the battery is not sufficiently developed.
In order to solve this problem, for example, Patent Document 1 has a current collector (metal foil or porous metal sheet) carrying electrode active material particles treated with a surfactant, particularly a fluorosurfactant. Proposed a technique for preventing the aggregation of the electrode active material particles, improving the uniform dispersibility, and improving the adhesion of the electrode active material to the support.

  Similarly, Patent Documents 2 to 4 disclose nonaqueous electrolyte secondary batteries in which a fluorosurfactant is included in an electrode.

Japanese Unexamined Patent Publication No. 7-037578 JP 2001-250558 A JP 2012-234665 A JP 2010-205449 A

However, in the manufactured non-aqueous electrolyte secondary battery, if the surfactant remains in the electrode active material, the surfactant decomposes in the electrode during operation of the non-aqueous electrolyte secondary battery, and the battery There is a possibility of decreasing the capacity.
In view of such circumstances, the present invention provides a method for producing a negative electrode for a nonaqueous electrolyte secondary battery that exhibits high capacity and high cycle characteristics, a negative electrode produced by the method, and a nonaqueous electrolyte secondary battery using the same. The purpose is to provide.

In view of the above circumstances, as a result of repeated studies by the present inventor, a specific low molecular weight surfactant is contained in the electrode slurry, and the surfactant is removed when the electrode is dried. The present inventors have found that the battery performance deterioration is suppressed and a high capacity is exhibited, and the present invention has been completed.
In the method for producing a negative electrode for a non-aqueous electrolyte secondary battery according to the present invention, desorption and insertion of lithium ions proceed at 0.3 V (vs. Li ⁺ / Li) or more and 2.0 V (vs. Li ⁺ / Li) or less. A paste is prepared by mixing one or both of the active electrode active material, the kitten represented by the following formula (1) and the diol represented by the following formula (2), and the paste is formed on the conductive foil. Thus, a negative electrode for a non-aqueous electrolyte secondary battery is manufactured.

(R ¹ and R ^{2 in the} formulas (1) and (2) are each an alkyl group having 1 to 10 carbon atoms and containing at least one fluorine atom, and R ¹ and R ² are They may be the same or different).
The electrode active material is preferably at least one selected from the group consisting of Li ₄ Ti ₅ O ₁₂ , H ₂ Ti ₁₂ O ₂₅ and TiO ₂ (B).

In the method for producing a negative electrode for a non-aqueous electrolyte secondary battery of the present invention, R ¹ and R ² in the chiton and diol represented by the formula (1) and the formula (2) are —CF ₃ or —CF ₂ CF _3. It is preferable that
The negative electrode for nonaqueous electrolyte secondary batteries can be obtained by using the method for producing a negative electrode for nonaqueous electrolyte secondary batteries of the present invention.

  A nonaqueous electrolyte secondary battery can be produced using the negative electrode for a nonaqueous electrolyte secondary battery of the present invention.

  The negative electrode for a non-aqueous electrolyte secondary battery of the present invention can be easily manufactured, and a non-aqueous electrolyte secondary battery using the negative electrode can exhibit a high capacity.

Embodiments of the present invention will be described below.
The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
<1. Negative electrode>
In the negative electrode used in the non-aqueous electrolyte secondary battery of the present invention, the lithium ion insertion / extraction reaction proceeds at 0.3 V (vs. Li ⁺ / Li) or more and 2.0 V (vs. Li ⁺ / Li) or less. Includes electrode active material.

When the insertion reaction of lithium ions proceeds at 0.3 V (vs. Li ⁺ / Li) or more and 2.0 V (vs. Li ⁺ / Li) or less, the insertion of lithium ions into the negative electrode active material is 2.0 V (vs. Li). Li ⁺ / Li) or less, and end at 0.3 V (vs. Li ⁺ / Li) or more. On the other hand, if the lithium ion desorption reaction proceeds at 0.3 V (vs. Li ⁺ / Li) or more and 2.0 V (vs. Li ⁺ / Li) or less, the lithium ion desorption from the negative electrode active material is 0. It starts at 3 V (vs. Li ⁺ / Li) or higher and ends at 2.0 V (vs. Li ⁺ / Li) or lower.

The voltage value (vs. Li ⁺ / Li) of the lithium ion insertion / desorption reaction is measured, for example, by measuring the charge / discharge characteristics of the working electrode using the negative electrode active material and the half cell using lithium metal as the counter electrode, and starting the plateau And by reading the voltage value at the end. If plateau had two or more places, as long plateau lowest voltage value is 0.3V (vs.Li ⁺ / Li) or more, plateau highest voltage value is 2.0V (vs.Li ⁺ / Li) It may be the following. The working electrode, electrolytic solution, and separator used for the half battery can be the same as those described later.

The negative electrode active material in which the insertion / extraction reaction of lithium ions proceeds at 0.3 V (vs. Li ⁺ / Li) or more and 2.0 V (vs. Li ⁺ / Li) or less is a titanate compound, lithium titanate, Titanium, niobium pentoxide, molybdenum dioxide, and the like are preferable, and lithium titanate, titanium dioxide, and titanic acid compounds are more preferable from the viewpoint of high stability of the negative electrode active material. One type of these negative electrode active materials may be used, or two or more types may be used. The negative electrode active material may be covered with a carbon material, a metal oxide, a polymer, or the like in order to improve conductivity or stability.

The lithium titanate preferably has a spinel structure or a ramsdellite type, and a molecular formula represented by Li ₄ Ti ₅ O ₁₂ is preferable. In the case of the spinel structure, the expansion / contraction of the electrode active material in the reaction of insertion / extraction of lithium ions is small. Lithium titanate may contain a small amount of elements other than lithium such as Nb and titanium, for example.
The particle size of lithium titanate is preferably 0.2 μm or more and 50 μm or less, and more preferably 0.5 μm or more and 30 μm or less from the viewpoint of handling.

The particle diameter is a value obtained by measuring the size of each particle from SEM and TEM images and calculating the average when the particle is spherical, and when the particle is other than spherical, the maximum side of the particle. In order to calculate the average particle diameter, it is preferable to observe 10 or more arbitrary particles by the SEM observation.
The specific surface area of lithium titanate is preferably 0.1 m ² / g or more and 50 m ² / g or less because a desired output density is easily obtained. The specific surface area may be calculated by measurement using a mercury porosimeter or BET method.

The bulk density of lithium titanate is preferably 0.2 g / cm ³ or more and 1.5 g / cm ³ or less. 0.2 g / cm in the case of less than ³ tend to be economically disadvantageous because it requires a large amount of solvent in the step of preparing the slurry described below, 1.5 g / cm ³ greater than the later of conductive agent, and a binder Tend to be difficult to mix.
The titanium dioxide used in the present invention is preferably anatase type or bronze type (TiO ₂ (B)), more preferably bronze type. Also, a mixture of anatase type and bronze type may be used.

The particle diameter of titanium dioxide is preferably 0.1 μm or more and 50 μm or less, and more preferably 0.2 μm or more and 30 μm or less from the viewpoint of handling.
The specific surface area of titanium dioxide is preferably 0.1 m ² / g or more and 50 m ² / g or less because a desired output density is easily obtained.
The bulk density of titanium dioxide is preferably 0.2 g / cm ³ or more and 1.5 g / cm ³ or less. 0.2 g / cm in the case of less than ³ tend to be economically disadvantageous because it requires a large amount of solvent in the step of preparing the slurry described below, 1.5 g / cm ³ greater than the later of conductive agent, and a binder Tend to be difficult to mix.

The titanic acid compound used in the present invention is preferably H ₂ Ti ₃ O ₇ , H ₂ Ti ₄ O ₉ , H ₂ Ti ₅ O ₁₁ , H ₂ Ti ₆ O ₁₃ , H ₂ Ti ₁₂ O ₂₅ , ₂ Ti ₁₂ O ₂₅ is more preferable.
The particle diameter of the titanic acid compound is preferably 0.1 μm or more and 50 μm or less, and more preferably 0.2 μm or more and 30 μm or less from the viewpoint of handling.

The specific surface area of titanium dioxide is preferably 0.1 m ² / g or more and 50 m ² / g or less because a desired output density is easily obtained.
The bulk density of titanium dioxide is preferably 0.2 g / cm ³ or more and 1.5 g / cm ³ or less. 0.2 g / cm in the case of less than ³ tend to be economically disadvantageous because it requires a large amount of solvent in the step of preparing the slurry described below, 1.5 g / cm ³ greater than the later of conductive agent, and a binder Tend to be difficult to mix.

The negative electrode of the present invention may contain a conductive additive. Although it does not specifically limit as a conductive support material, A carbon material is preferable. Examples thereof include natural graphite, artificial graphite, vapor grown carbon fiber, carbon nanotube, acetylene black, ketjen black, and furnace black. These carbon materials may be used alone or in combination of two or more.
The amount of the conductive additive contained in the negative electrode is preferably 1 part by weight or more and 30 parts by weight or less, more preferably 2 parts by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the negative electrode active material. If it is the said range, the electroconductivity of a negative electrode will be ensured. Moreover, adhesiveness with the below-mentioned binder is maintained, and adhesiveness with a collector can fully be obtained.

  It is preferable to use a binder for the negative electrode of the present invention. The binder is not particularly limited, and for example, at least one selected from the group consisting of polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber, polyimide, and derivatives thereof can be used. . The binder is preferably dissolved or dispersed in a non-aqueous solvent or water from the viewpoint of easy production of the negative electrode. The non-aqueous solvent is not particularly limited, and examples thereof include N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, methyl acetate, ethyl acetate, and tetrahydrofuran. You may add a thickener to these.

The amount of the binder contained in the negative electrode is preferably 1 part by weight or more and 30 parts by weight or less, more preferably 2 parts by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the negative electrode active material. If it is the said range, the adhesiveness of a negative electrode active material and a conductive support material will be maintained, and adhesiveness with a collector can fully be acquired.
The negative electrode of the present invention is produced from a negative electrode paste containing a compound represented by either or both of a kitten represented by the following formula (1) and a diol represented by the following formula (2).

(R ¹ and R ^{2 in the} formulas (1) and (2) each represent an alkyl group having C1 to C10, that is, 1 to 10 carbon atoms, and containing at least one fluorine atom, and R ¹ And R ² may be the same or different.
Below chiton and diols of the formula (2) in the formula (1) which may each ^R 1 ^R 2 C = represented as O and ^R 1 ^R 2 C _{(OH) 2.}

The kitten of the formula (1) reacts with a small amount of water contained in the negative electrode paste, and most of it exists in the negative electrode paste as the diol of the formula (2) in the equilibrium formula of the following formula (3). That is, in the present invention, even if any compound of the formula (1) or (2) is added to the negative electrode paste, most of the compound exists as the formula (2).
R ¹ R ² C═O + H ₂ O⇔ R ¹ R ² C (OH) ₂ (3)
The effect of mixing the compound of the formula (1) or (2) is that the diol of the formula (2) works as a surfactant. That is, the aggregation of the electrode active material can be suppressed by using the low molecular weight kitten of the formula (1) and the diol of the formula (2) as the surfactant.

  Further, the characteristics of the kitten of the formula (1) and the diol of the formula (2) are that the molecular weight is low and the boiling point is low, so that it can be removed when the electrode is dried. That is, when the produced electrode is dried, the kitten of the formula (1) and the diol of the formula (2) can be removed, whereby the kitten of the formula (1) and the formula (2) at the time of electrode charging and discharging are removed. It becomes possible to suppress decomposition of the diol.

The residual amount of the kitten of the formula (1) and the diol of the formula (2) after drying the negative electrode can be measured by, for example, an X-ray photoelectron spectroscopy (ESCA).
The type of ESCA is not particularly limited, but is preferably performed under the following conditions. The X-ray source of ESCA is exemplified by AlKα, MgKα, AgKα, etc., but AlKα is preferable because it is widely used. The intensity of the X-ray is preferably 1 kV or more and 20 kV or less. If it is less than 1 kV, the element to be measured may not be detected, and if it is greater than 20 kV, the sample may be destroyed. The measurement range is preferably a circle having a diameter of 100 μm or more. If the thickness is less than 100 μm, the element to be measured may not be detected.

The element concentration ratio of each element is obtained by correcting the peak intensity of each element with the relative sensitivity coefficient of each element.
The kitten of the formula (1) and the diol of the formula (2) used in the present invention contain at least one fluorine atom. By containing fluorine atoms, it is possible to reduce the surface tension of the material in a small amount. Further, by including a fluorine atom, the equilibrium formula of the formula (3) moves to the right side, the ratio of the diol of the formula (2) as an active ingredient is increased, and the chiton of the formula (1) and the The effect of the diol of formula (2) is further improved.

The alkyl group having 1 to 10 carbon atoms and containing at least one fluorine atom is not particularly limited, but is —CF ₃ , —CF ₂ Cl, —CFCl ₂ , —CF _2. CF ₃ , —CF (CF ₃ ) ₂ , —CF ₂ CF ₂ CF ₃ , —CF ₂ CF ₂ CF ₃ CF ₃ , —C (CF ₃ ) ₃ , —CF ₂ OCH ₃ , or —CF (OCH ₃ ) _{2 and the} like, -CF ₃ , -CF ₂ CF ₃ , -CF (CF ₃ ) ₂ , -CF ₂ CF ₂ CF ₃ , -CF ₂ CF ₂ CF ₃ CF ₃ , -C (CF ₃ ) ₃ More preferred is —CF ₃ , —CF ₂ CF _3, particularly preferred. By including -CF ₃ and -CF ₂ CF ₃ , the boiling point of the kitten of the formula (1) and the diol of the formula (2) is lowered, and the removal at the time of electrode drying becomes easier.

  The method for producing the negative electrode is not limited. For example, a negative electrode active material, a conductive additive, a binder, and a mixture of the kitten of the formula (1) and the diol of the formula (2) (hereinafter referred to as “negative electrode mixture”) are collected. It is produced by forming on an electric body. For ease of production, a slurry is prepared with the negative electrode mixture and a solvent, and after the obtained slurry is applied on a current collector, the solvent, the kitten of the formula (1), and the diol of the formula (2) A method of producing a negative electrode by removing the is preferable.

  The concentration of the kitten of the formula (1) and the diol of the formula (2) in the slurry is not particularly limited as long as the aggregation of the electrode active material is suppressed and the battery characteristics are not adversely affected. In order to exhibit the function of the kitten of the formula (1) and the diol of the formula (2) more effectively, it may be in the range of 0.01 to 10 with respect to 100 parts by weight of the electrode active material. A range of 0.05 to 5 is preferable.

When the kitten of the formula (1) and the diol of the formula (2) are gases at normal temperature and pressure, a hydrate of the kitten of the formula (1) and the diol of the formula (2) may be used. Hydrates are substances that contain water molecules. By using a hydrate, it may be possible to simply add the kitten of formula (1) and the diol of formula (2).
The current collector that can be used for the negative electrode of the present invention is a metal that is stable at 0.3 V (vs. Li ⁺ / Li) or more and 2.0 V (vs. Li ⁺ / Li) or less, such as copper, SUS, nickel. Titanium, aluminum and alloys thereof are preferred, and aluminum and copper are particularly preferred because of their high stability. Aluminum is not particularly limited because it is stable in the electrode reaction atmosphere of the positive electrode and the negative electrode, but is preferably high-purity aluminum represented by JIS standards 1030, 1050, 1085, 1N90, 1N99 and the like.

The surface roughness Ra of the current collector is preferably 0.05 μm or more and 0.5 μm or less. If it is less than 0.05 μm, the adhesion to the negative electrode may be lowered, and if it is larger than 0.5 μm, it may be difficult to produce the negative electrode uniformly. The surface roughness Ra can be measured using a light wave interference type surface roughness measuring instrument or the like.
The electrical resistance of the current collector is preferably 5 μΩ · cm or less. If it is higher than 5 μΩ · cm, the battery performance may be reduced. Electrical resistance can be measured by the four probe method.

The thickness of the current collector is not particularly limited, but is preferably 10 μm or more and 100 μm or less. If it is less than 10 μm, handling is difficult from the viewpoint of production, and if it is thicker than 100 μm, it is disadvantageous from an economic viewpoint.
The current collector may be a metal material other than aluminum (copper, SUS, nickel, titanium, and alloys thereof) coated with aluminum.

  Although the preparation apparatus of a slurry is not specifically limited, Since negative mix (a negative electrode active material, a conductive support material, a binder, the kitten of said Formula (1), and the diol of said Formula (2)), and a solvent can be mixed uniformly. It is preferable to use a ball mill, a planetary mixer, a jet mill, a rotating / revolving mixer, or a thin film swirling mixer. Although the preparation procedure of the slurry is not particularly limited, it may be prepared by adding a solvent after mixing the negative electrode active material, the conductive additive, the kitten of formula (1) and the diol of formula (2), and the binder. Alternatively, the negative electrode active material, the conductive additive, the binder, the kitten of the formula (1), the diol of the formula (2), and the solvent may be mixed together.

The solid content concentration of the slurry is preferably 30 wt% or more and 80 wt% or less. If it is less than 30 wt%, the viscosity of the slurry tends to be too low, whereas if it is higher than 80 wt%, the viscosity of the slurry tends to be too high, which may make it difficult to produce an electrode described later.
The solvent used for the slurry is preferably a non-aqueous solvent or water. The non-aqueous solvent is not particularly limited, and examples thereof include N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, methyl acetate, ethyl acetate, and tetrahydrofuran. Moreover, you may add a thickener to these.

  The method for forming the negative electrode on the current collector is not particularly limited. For example, after applying the slurry with a doctor blade, a die coater, a comma coater, or the like, the solvent, the chiton of the formula (1), and the formula (2) A forming method for removing the diol or a forming method for removing the solvent, the kitten of the formula (1) and the diol of the formula (2) after applying the slurry by spraying is preferable.

  The method for removing the solvent, the kitten of the formula (1) and the diol of the formula (2) is preferable because it is easy to dry using an oven or a vacuum oven. Examples of the atmosphere include room temperature or high temperature air, an inert gas, and a vacuum state. Alternatively, after removing the solvent by performing primary drying at a low temperature, secondary drying may be performed at a higher temperature to remove the kitten of formula (1) and the diol of formula (2). Moreover, you may compress a negative electrode using a roll press machine etc. after negative electrode preparation. The electrode may be compressed before or after the positive electrode is manufactured.

The heating temperature when heating the negative electrode is preferably 60 ° C. or more and 300 ° C. or less, and more preferably 80 ° C. or more and 200 ° C. or less. When the temperature is 60 ° C. or lower, it takes time to remove the solvent, the kitten of the formula (1) and the diol of the formula (2), and when the temperature is 300 ° C. or higher, the electrode material may decompose.
The thickness of the negative electrode after drying is preferably 10 μm or more and 200 μm or less on one side. If it is 10 μm or less, it may be difficult to obtain a desired capacity, and if it is thicker than 200 μm, it may be difficult to obtain a desired output density.

The density of the negative electrode (excluding the current collector) after drying is preferably 0.8 g / cm ³ or more and 4.0 g / cm ³ or less. If it is less than 0.8 g / cm ³ , the contact between the negative electrode active material and the conductive additive becomes insufficient, and the electronic conductivity may decrease. When it is larger than 4.0 g / cm ³ , an electrolyte solution described later hardly penetrates into the negative electrode, and the lithium ion conductivity may be lowered.

The negative electrode may be compressed to a desired thickness and density. The compression method is not particularly limited, and can be performed using, for example, a roll press, a hydraulic press, or the like. The negative electrode may be compressed before or after the positive electrode described later is manufactured.
In the present invention, the electric capacity per 1 cm ² area of the negative electrode is preferably 0.5 mAh or more and 5.0 mAh or less. If it is less than 0.5 mAh, the battery capacity may increase with respect to the desired capacity, while if it exceeds 5.0 mAh, it may be difficult to obtain the desired output density. The method for calculating the electric capacity per 1 cm ² of the area of the negative electrode can be calculated by measuring the charge / discharge characteristics after preparing the negative electrode and then preparing a half-cell using lithium metal as a counter electrode. The method of controlling the electric capacity per 1 cm ^{2 of the} negative electrode area is not particularly limited, but is controlled by the weight of the negative electrode produced per unit area of the current collector, for example, controlled by the coating thickness at the time of the negative electrode coating described above. can do.

<2. Positive electrode>
The positive electrode active material contained in the positive electrode of the non-aqueous electrolyte secondary battery of the present invention is not particularly limited, and may be a lithium transition metal compound, such as a lithium cobalt compound, a lithium nickel compound, a lithium manganese compound, and a lithium iron compound. Is exemplified. Moreover, a transition metal is not limited to one type, Two or more types may be sufficient. For example, a lithium cobalt nickel manganese compound, a lithium nickel manganese compound, etc. are illustrated. Moreover, since the effect which improves the stability of a lithium transition metal compound is high, elements, such as aluminum, magnesium, titanium, may be contained in trace amounts, for example.

The surface of the positive electrode active material may be covered with a carbon material, a metal oxide, a polymer, or the like in order to improve conductivity or stability.
The positive electrode may contain a conductive additive. Although it does not specifically limit as a conductive support material, A carbon material is preferable. Examples thereof include natural graphite, artificial graphite, vapor grown carbon fiber, carbon nanotube, acetylene black, ketjen black, and furnace black. These carbon materials may be used alone or in combination of two or more.

The amount of the conductive additive contained in the positive electrode is preferably 1 part by weight or more and 30 parts by weight or less, more preferably 2 parts by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the positive electrode active material. If it is the said range, the electroconductivity of a positive electrode will be ensured. Moreover, adhesiveness with the below-mentioned binder is maintained, and adhesiveness with a collector can fully be obtained.
The positive electrode may contain a binder. The binder is not particularly limited, and for example, at least one selected from the group consisting of polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber, polyimide, acrylic resin, and derivatives thereof is used. be able to. The binder is preferably dissolved or dispersed in a non-aqueous solvent or water from the viewpoint of easy production of the positive electrode. The non-aqueous solvent is not particularly limited, and examples thereof include N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, methyl acetate, ethyl acetate, and tetrahydrofuran. You may add a dispersing agent and a thickener to these.

The amount of the binder contained in the positive electrode is preferably 1 part by weight or more and 30 parts by weight or less, more preferably 2 parts by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the positive electrode active material. If it is the said range, the adhesiveness of a positive electrode active material and a conductive support material will be maintained, and adhesiveness with a collector can fully be acquired.
Examples of the method for producing the positive electrode include a method for producing a positive electrode active material, a conductive additive, and a binder by coating a current collector on the current collector. A method of producing a positive electrode by producing a slurry and coating the obtained slurry on a current collector and then removing the solvent is preferred.

The current collector used for the positive electrode is preferably aluminum or an alloy thereof. The aluminum is not particularly limited because it is stable in a positive electrode reaction atmosphere, but is preferably high-purity aluminum represented by JIS standards 1030, 1050, 1085, 1N90, 1N99 and the like.
Note that the current collector may be a metal whose surface is covered with aluminum other than aluminum (copper, SUS, nickel, titanium, and alloys thereof).

<3. Separator>
The separator used for the non-aqueous electrolyte secondary battery of the present invention may be any substance that is installed between the positive electrode and the negative electrode and has no electronic conductivity and lithium ion conductivity. For example, nylon, cellulose, polysulfone, polyethylene, polypropylene, polybutene, polyacrylonitrile, polyimide, polyamide, and a woven fabric, a nonwoven fabric, a microporous membrane, or the like obtained by combining two or more of these may be used. The separator may include various plasticizers, antioxidants, flame retardants, and may be coated with a metal oxide or the like.

The thickness of the separator is preferably 10 μm or more and 100 μm or less. When the thickness is less than 10 μm, the positive electrode and the negative electrode may come into contact with each other. When the thickness is greater than 100 μm, the battery resistance may increase. From the viewpoint of economy and handling, it is more preferably 15 μm or more and 50 μm or less.
<4. Non-aqueous electrolyte>
The non-aqueous electrolyte used in the non-aqueous electrolyte secondary battery of the present invention is not particularly limited, but a polymer is impregnated with an electrolytic solution in which a solute is dissolved in a non-aqueous solvent, or an electrolytic solution in which a solute is dissolved in a non-aqueous solvent. A gel electrolyte or the like can be used.

The non-aqueous solvent preferably includes a cyclic aprotic solvent and / or a chain aprotic solvent. Examples of the cyclic aprotic solvent include cyclic carbonates, cyclic esters, cyclic sulfones and cyclic ethers. Examples of the chain aprotic solvent include chain carbonates, chain carboxylic acid esters and chain ethers.
In addition to the above, a solvent generally used as a solvent for nonaqueous electrolytes such as acetonitrile may be used. More specifically, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyl lactone, 1,2-dimethoxyethane, sulfolane, dioxolane, propion For example, methyl acid can be used. These solvents may be used alone or as a mixture of two or more. However, in view of the ease of dissolving the solute described below and the high conductivity of lithium ions, a mixture of two or more of these solvents. Is preferably used. A gel electrolyte in which an electrolyte is impregnated in a polymer can also be used.

The solute is not particularly limited. For example, LiClO ₄ , LiBF ₄ , LiPF ₆ , LiAsF ₆ , LiCF ₃ SO ₃ , LiBOB (Lithium Bis (Oxalato) Borate), LiN (SO ₂ CF ₃ ) _2, etc. are dissolved in the solvent. It is preferable because it is easy to do. The concentration of the solute contained in the electrolytic solution is preferably 0.5 mol / L or more and 2.0 mol / L or less. If it is less than 0.5 mol / L, the desired lithium ion conductivity may not be expressed. On the other hand, if it is higher than 2.0 mol / L, the solute may not be dissolved any more. The non-aqueous electrolyte may contain a trace amount of additives such as a flame retardant and a stabilizer.

<5. Non-aqueous electrolyte secondary battery>
The positive electrode and the negative electrode of the nonaqueous electrolyte secondary battery of the present invention may be in the form in which the same electrode is formed on both sides of the current collector, and the positive electrode is formed on one side of the current collector and the negative electrode is formed on one side. Alternatively, it may be a bipolar electrode.
The nonaqueous electrolyte secondary battery of the present invention may be one obtained by winding or laminating a separator disposed between the positive electrode side and the negative electrode side. The positive electrode, the negative electrode, and the separator contain a nonaqueous electrolyte that is responsible for lithium ion conduction.

The amount of the nonaqueous electrolyte used in the nonaqueous electrolyte secondary battery of the present invention is not particularly limited, but is preferably 0.1 mL or more per 1 Ah of battery capacity. If it is less than 0.1 mL, the conduction of lithium ions accompanying the electrode reaction may not catch up, and the desired battery performance may not be exhibited.
The nonaqueous electrolyte may be added to the positive electrode, the negative electrode, and the separator in advance, or may be added after winding or laminating a separator disposed between the positive electrode side and the negative electrode side.

The non-aqueous electrolyte secondary battery of the present invention may be wound or laminated with a laminate film after the laminate is wound, or may be rectangular, elliptical, cylindrical, coin-shaped, button-shaped, or sheet-shaped. It may be packaged with a metal can. The exterior may be provided with a mechanism for releasing the generated gas. The number of stacked layers can be stacked until a desired voltage value and battery capacity are exhibited.
The nonaqueous electrolyte secondary battery of the present invention can be formed into an assembled battery by connecting a plurality of the nonaqueous electrolyte secondary batteries. The assembled battery of this invention can be manufactured by connecting in series and parallel suitably according to desired magnitude | size, a capacity | capacitance, and a voltage. Moreover, it is preferable that a control circuit is attached to the assembled battery in order to confirm the state of charge of each battery and improve safety.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited at all by these Examples, In the range which does not change the summary, it can change suitably.
1. 1. Synthesis of negative electrode active material 1-1. Synthesis of Lithium Titanate Li ₄ Ti ₅ O ₁₂ as a negative electrode active material was obtained from the literature ("Zero-Strain Insertion Material of Li [Li1 / 3Ti5 / 3] O4 for Rechargeable Lithium Cells" J. Electrochem. Soc., Volume 142, Issue 5, pp. 1431-1435 (1995)).

That is, first, titanium dioxide and lithium hydroxide were mixed so that the molar ratio of titanium and lithium was 5: 4, and then this mixture was heated at 800 ° C. for 12 hours in a nitrogen atmosphere to obtain Example 1. A negative electrode active material to be used was prepared.
1-2. Bronze-type titanium dioxide _(TiO 2 (B)) of the synthesis the anode active material of _TiO. 2 (B), literature ( "Improvement of the Reversible Capacity of TiO2 (B) High Potential Negative Electrode" J. Electrochem. Soc. 159 ( 1), A49-A54 (2012)).

That is, first, the molar ratio of titanium dioxide and potassium carbonate is mixed so as to be 4: 1, and then this mixture is heated twice at 1000 ° C. for 24 hours in the atmosphere to thereby obtain K ₂ Ti ₄ O _9. Got. The negative electrode active material used in Example 5 was prepared by heating H ₂ Ti ₄ O ₉ obtained after treating K ₂ Ti ₄ O ₉ with a 1.0 M aqueous hydrochloric acid solution at 500 ° C. for 0.5 hour. .

1-3. Titanic acid compound _H 2 _Ti 12 _{O 25} Synthesis anode active material of the titanic acid compound _H 2 _Ti 12 _{O 25,} the document (J. Akimoto et al .: Journal of The Electrochemical Society, 158, A546-A549 (2011)) It was produced by the method described in 1.
That is, first, the molar ratio of titanium dioxide and sodium carbonate was mixed to be 3: 1, and then this mixture was heated twice at 800 ° C. for 20 hours in the atmosphere to thereby Na ₂ Ti ₃ O _7. Got. The negative electrode active material used in Example 9 was prepared by heating H ₂ Ti ₃ O ₇ obtained after treating Na ₂ Ti ₃ O ₇ with a 0.5 M aqueous hydrochloric acid solution at 260 ° C. for 5 hours.

2. Hydrates of (CF ₃ ) ₂ C═O and (CF ₃ CF ₂ ) ₂ C═O were prepared as the chitone and diol represented by the formula (1) and the formula (2) to be added to the negative electrode active material. . The weight parts of (CF ₃ ) ₂ C═O and (CF ₃ CF ₂ ) ₂ C═O in the following examples are not parts by weight as hydrates, but are represented by the above formula (1) and the above formula (2). The parts by weight of the kitten and diol shown are shown. Moreover, perfluorooctane sulfonic acid was prepared for the comparative example. Perfluorooctane sulfonic acid is a type of surfactant and a type of sulfonic acid having a fully fluorinated linear alkyl group.

The boiling point of kitten (CF ₃ ) ₂ C═O is about −28 ° C. at normal pressure, and the boiling point of kitten (CF ₃ CF ₂ ) ₂ C═O is about 48 ° C. at normal pressure. On the other hand, the boiling point of perfluorooctane sulfonic acid is higher than that of chiton (CF ₃ ) ₂ C═O and chiton (CF ₃ CF ₂ ) ₂ C═O, so that the boiling point of perfluorooctane sulfonic acid is about 133 ° C. at 6 torr.
3. Fabrication of positive electrode (common to Examples and Comparative Examples)
Li _1.1 Al _0.1 Mn _1.8 O ₄ as a positive electrode active material is described in the literature (“Lithium Aluminum Manganese Oxide Having Spinel-Framework Structure for Long-Life Lithium-Ion Batteries” Electrochemical and Solid-State Letters Volume 9, Issue 12, Pages A557 (2006)).

  That is, an aqueous dispersion of manganese dioxide, lithium carbonate, aluminum hydroxide, and boric acid was prepared, and a mixed powder was prepared by a spray drying method. At this time, the amounts of manganese dioxide, lithium carbonate and aluminum hydroxide were adjusted so that the molar ratio of lithium, aluminum and manganese was 1.1: 0.1: 1.8. Next, the mixed powder was heated at 900 ° C. for 12 hours in an air atmosphere, and then again heated at 650 ° C. for 24 hours. Finally, the powder was washed with water at 95 ° C. and dried to prepare a positive electrode active material.

100 parts by weight of the positive electrode active material, 6.8 parts by weight of conductive additive (acetylene black), and 6.8 parts by weight of binder (solid content concentration 12 wt%, NMP solution) are added to the container. The slurry was prepared by stirring for 10 minutes at 2000 rpm and performing defoaming for 1 minute at 2200 rpm. The slurry was applied to an aluminum foil (20 μm) and then vacuum-dried at 150 ° C. to produce a positive electrode (area 50 cm ² ).

The capacity of the positive electrode was measured by the following charge / discharge test.
The electrode coated on one side of the aluminum foil was punched to 16 mmΦ, and the Li metal was punched to 16 mmΦ as a counter electrode. Using these electrodes, the working electrode (single-sided coating) / separator / Li metal were laminated in this order in a test cell (HS cell, manufactured by Hosen Co., Ltd.), and a non-aqueous electrolyte (ethylene carbonate / dimethyl carbonate = 30/70 vol). %, LiPF ₆ 1 mol / L) was added to prepare a half cell. The half-cell was allowed to stand at 25 ° C. for one day, and then connected to a charge / discharge test apparatus (HJ1005SD8, manufactured by Hokuto Denko). The half-cell was subjected to constant current charging (end voltage: 4.5 V) and constant current discharge (end voltage: 3.5 V) at 25 ° C. and 0.4 mA five times, and the fifth result was taken as the positive electrode capacity. As a result, the capacity of the positive electrode was 93 mAh / g, and the capacity per unit area was 1.3 mAh / cm ² .

4). Production of non-aqueous electrolyte secondary batteries (Examples 1 to 9, Comparative Examples 1 to 4)
A negative electrode is manufactured by specifying a combination of the three types of titanium oxides synthesized as described above and a compound added to the negative electrode active material, and non-aqueous electrolyte secondary batteries according to nine examples and four comparative examples are manufactured. did.
<Example 1>
100 parts by weight of lithium titanate Li ₄ Ti ₅ O ₁₂ (5 g) synthesized by the above method, 6.8 parts by weight of conductive additive (acetylene black), and 0.5 parts by weight of (CF ₃ ) ₂ C═O A negative electrode mixture was prepared by mixing 6.8 parts by weight of a binder (solid content concentration: 12 wt%, NMP solution) in terms of solid content.

This negative electrode mixture was put into a container, stirred for 10 minutes at 2000 rpm using a rotation and revolution mixer, and then defoamed at 2200 rpm for 1 minute to prepare a slurry. The slurry was applied to an aluminum foil (thickness: 20 μm), vacuum-dried at 120 ° C. for 1 hour, and then further vacuum-dried at 170 ° C. for 12 hours to prepare a negative electrode (area 50 cm ² ). As a result of surface analysis of the produced negative electrode by ESCA, fluorine could not be confirmed (it seems to have been removed when the electrode was dried).

The capacity of the negative electrode was measured by the following charge / discharge test.
The negative electrode was punched to 16 mmΦ and used as a working electrode, and Li metal was punched to 16 mmΦ as a counter electrode. Using these electrodes, the working electrode (single-sided coating) / separator / Li metal were laminated in this order in a test cell (HS cell, manufactured by Hosen Co., Ltd.), and a non-aqueous electrolyte (ethylene carbonate / dimethyl carbonate = 30/70 vol). %, LiPF ₆ 1 mol / L) was added to prepare a half cell. The half-cell was allowed to stand at 25 ° C. for one day, and then connected to a charge / discharge test apparatus (HJ1005SD8, manufactured by Hokuto Denko). The half battery was measured for charge capacity after repeating constant current discharge (end voltage: 1.0 V) and constant current charge (end voltage: 3.0 V) at 25 ° C. and 0.5 mA five times to find 166 mAh / g. The capacity per unit area was 1.1 mAh / cm ² .

The nonaqueous electrolyte secondary battery was manufactured as follows.
The electrode which coated the positive electrode and the negative electrode on one side of the aluminum foil was used. Cellulose unwoven cloth (25 μm, 55 cm ² ) was used as the separator. First, the produced positive electrode (single-sided coating), the negative electrode of Example 1 (single-sided coating), and a separator were laminated in the order of positive electrode (single-sided coating) / separator / negative electrode (single-sided coating). Next, aluminum tabs (to be lead electrodes) were vibration welded to the positive and negative electrodes at both ends, and then put into a bag-like aluminum laminate sheet.

After 2 mL of non-aqueous electrolyte (ethylene carbonate / dimethyl carbonate = 30/70 vol%, LiPF ₆ 1 mol / L) was added to the aluminum laminate sheet, the non-aqueous electrolyte secondary battery was sealed by sealing under reduced pressure. Produced.
The nonaqueous electrolyte secondary battery was connected to a charging / discharging device (HJ1005SD8, manufactured by Hokuto Denko), and 25 ° C., 50 mA constant current charging, and 50 mA constant current discharging were repeated 10 times. When the charge end voltage and the discharge end voltage were 2.7 V and 2 V, respectively, the first discharge capacity was 164 mAh / g, and the tenth discharge capacity with respect to the first time was 97%.

<Example 2>
A negative electrode for a nonaqueous electrolyte secondary battery and a half-cell were produced in the same manner as in Example 1 except that 5.0 parts by weight of (CF ₃ ) ₂ C═O was used. This half-cell was charged at 166 mAh / g after repeating constant current discharge (end voltage: 1.0 V) and constant current charge (end voltage: 3.0 V) at 25 ° C. and 0.5 mA five times. . Further, as a result of surface analysis of the produced negative electrode by ESCA, fluorine could not be confirmed.

<Example 3>
A negative electrode for a nonaqueous electrolyte secondary battery and a half battery were prepared in the same manner as in Example 1 except that 0.1 part by weight of (CF ₃ ) ₂ C═O was used. This half-cell was charged with a constant capacity of 163 mAh / g after 5 times of constant current discharge (end voltage: 1.0 V) and constant current charge (end voltage: 3.0 V) at 25 ° C. and 0.5 mA. . Further, as a result of surface analysis of the produced negative electrode by ESCA, fluorine could not be confirmed.

<Example 4>
(CF ₃₎ changes to _{2 C = O (CF 3 CF} 2) Except for using ₂ C = O to produce a negative electrode, and a half-cell for a non-aqueous electrolyte secondary battery in the same manner as in Example 1. The half battery was charged with a constant current of 161 mAh / g after 5 times of constant current discharge (end voltage: 1.0 V) and constant current charge (end voltage: 3.0 V) at 25 ° C. and 0.5 mA. . Further, as a result of surface analysis of the produced negative electrode by ESCA, fluorine could not be confirmed.

<Example 5>
100 parts by weight of bronze-type titanium dioxide (TiO ₂ (B)) (3 g) synthesized by the above method, 6.8 parts by weight of a conductive additive (Ketjen Black), and (CF ₃ ) ₂ C═O of 0. 5 parts by weight, binder (solid content 12 wt%, NMP solution) 6.8 parts by weight solids and NMP 25 parts by weight are added to a container and stirred for 10 minutes at 2000 rpm using a rotating and rotating mixer, then 1 at 2200 rpm. Slurries were made by performing defoaming for minutes. After coating this slurry on copper foil (20 μm), it was vacuum dried at 120 ° C. for 1 hour, and then further vacuum dried at 170 ° C. for 12 hours to produce a negative electrode (area 50 cm ² ).

As a result of surface analysis of the prepared negative electrode by ESCA, fluorine could not be confirmed. Further, a half cell was prepared in the same manner as in Example 1, and constant current discharge (end voltage: 1.0 V) and constant current charge (end voltage: 3.0 V) were repeated 5 times at 25 ° C. and 0.5 mA. The later charge capacity was 236 mAh / g.
<Example 6>
A negative electrode for a nonaqueous electrolyte secondary battery and a half battery were produced in the same manner as in Example 5 except that 5.0 parts by weight of (CF ₃ ) ₂ C═O was used. This half-cell was charged with a constant capacity of 231 mAh / g after 5 times of constant current discharge (end voltage: 1.0 V) and constant current charge (end voltage: 3.0 V) at 25 ° C. and 0.5 mA. . Further, as a result of surface analysis of the produced negative electrode by ESCA, fluorine could not be confirmed.

<Example 7>
A negative electrode for a nonaqueous electrolyte secondary battery and a half-cell were produced in the same manner as in Example 5 except that 0.1 part by weight of (CF ₃ ) ₂ C═O was used. The half battery was charged with a constant current of 228 mAh / g after 5 times of constant current discharge (end voltage: 1.0 V) and constant current charge (end voltage: 3.0 V) at 25 ° C. and 0.5 mA. . Further, as a result of surface analysis of the produced negative electrode by ESCA, fluorine could not be confirmed.

<Example 8>
(CF ₃₎ changes to _{2 C = O (CF 3 CF} 2) Except for using ₂ C = O to produce a negative electrode, and a half-cell for a non-aqueous electrolyte secondary battery in the same manner as in Example 5. The half battery was charged with a constant charge of 225 mAh / g after 5 times of constant current discharge (end voltage: 1.0 V) and constant current charge (end voltage: 3.0 V) at 25 ° C. and 0.5 mA. . Further, as a result of surface analysis of the produced negative electrode by ESCA, fluorine could not be confirmed.

<Example 9>
100 parts by weight of titanic acid compound H ₂ Ti ₁₂ O ₂₅ (3 g) synthesized by the above method, 6.8 parts by weight of conductive auxiliary material (Ketjen black), 0.5 weight of (CF ₃ ) ₂ C═O 6.8 parts by weight of binder (solid content concentration 12 wt%, NMP solution) and 15 parts by weight of NMP were added to a container, stirred for 10 minutes at 2000 rpm using a rotating and rotating mixer, and then removed for 1 minute at 2200 rpm. A slurry was made by carrying out foaming. This slurry was applied to a copper foil (20 μm), and then vacuum dried at 120 ° C. for 1 hour, and then further vacuum dried at 170 ° C. for 12 hours to prepare a negative electrode (50 cm ² ).

As a result of surface analysis of the prepared negative electrode by ESCA, fluorine could not be confirmed. Further, a half cell was prepared in the same manner as in Example 1, and constant current discharge (end voltage: 1.0 V) and constant current charge (end voltage: 3.0 V) were repeated 5 times at 25 ° C. and 0.5 mA. The later charge capacity was 211 mAh / g.
<Comparative Example 1>
A negative electrode for a nonaqueous electrolyte secondary battery and a half battery were produced in the same manner as in Example 1 except that (CF ₃ ) ₂ C═O was not added. This half-cell was charged with a constant current of 151 mAh / g after 5 times of constant current discharge (end voltage: 1.0 V) and constant current charge (end voltage: 3.0 V) at 25 ° C. and 0.5 mA. . Further, as a result of surface analysis of the produced negative electrode by ESCA, fluorine could not be confirmed.

<Comparative example 2>
A negative electrode for a nonaqueous electrolyte secondary battery and a half cell were produced in the same manner as in Example 5 except that (CF ₃ ) ₂ C═O was not added. This half-cell was charged at a constant capacity of 196 mAh / g after 5 times of constant current discharge (end voltage: 1.0 V) and constant current charge (end voltage: 3.0 V) at 25 ° C. and 0.5 mA. . Further, as a result of surface analysis of the produced negative electrode by ESCA, fluorine could not be confirmed.

<Comparative Example 3>
A negative electrode for a nonaqueous electrolyte secondary battery and a half battery were produced in the same manner as in Example 9 except that (CF ₃ ) ₂ C═O was not added. The half-cell was charged with 178 mAh / g after repeating 5 times constant current discharge (end voltage: 1.0 V) and constant current charge (end voltage: 3.0 V) at 25 ° C. and 0.5 mA. . Further, as a result of surface analysis of the produced negative electrode by ESCA, fluorine could not be confirmed.

<Comparative Example 4>
A negative electrode for a nonaqueous electrolyte secondary battery and a half battery were produced in the same manner as in Example 1 except that perfluorooctanesulfonic acid was used instead of (CF ₃ ) ₂ C═O. The half-cell was charged with a constant capacity of 155 mAh / g after repeating constant current discharge (end voltage: 1.0 V) and constant current charge (end voltage: 3.0 V) at 25 ° C. and 0.5 mA five times. . As a result of analyzing the surface of the prepared negative electrode by ESCA, the elemental concentration of fluorine and titanium was 1: 3.3.
Table 1 summarizes the charge capacities after repeating the constant current charge / discharge of Examples 1 to 9 and Comparative Examples 1 to 4 five times. At this time, the final voltage during discharging was 1.0 V, and the final voltage during charging was 3.0 V.

In Examples and Comparative Examples, if the charge capacity after repeating constant current charge / discharge five times is 160 mAh / g or more when Li ₄ Ti ₅ O _{12 is} used as the negative electrode active material, a high capacity is exhibited. It was judged that When TiO ₂ (B) was used as the negative electrode active material, it was judged that a high capacity was developed if it was 220 mAh / g or more. When H ₂ Ti ₁₂ O ₂₅ was used as the negative electrode active material, it was judged that a high capacity was developed if it was 200 mAh / g or more.

As is clear from Table 1, the electrodes of Examples 1 to 9 of the present invention express high capacity, and the electrodes of Comparative Examples 1 to 3 and Comparative Example 4 do not express high capacity. This is because in Examples 1 to 9, when the produced slurry was applied to an aluminum foil, the chiton of the formula (1) and the diol of the formula (2) suppressed aggregation of the electrode active material. Conceivable.
In addition, when a surfactant having a high boiling point and cannot be removed is used as in Comparative Example 4, high capacity is not exhibited as in Example 1. This is thought to be due to the fact that the surfactant remained, the remaining surfactant was decomposed, and that the resistance component increased due to the decomposition product being deposited on the negative electrode surface, resulting in a decrease in capacity. It is done.

Claims (5)

An electrode active material in which desorption and insertion of lithium ions proceeds at 0.3 V (vs. Li ⁺ / Li) or more and 2.0 V (vs. Li ⁺ / Li) or less, a chiton represented by the following formula (1), A paste is prepared by mixing any one or both of the diols represented by the following formula (2),
A method for producing a negative electrode for a nonaqueous electrolyte secondary battery, wherein the negative electrode for a nonaqueous electrolyte secondary battery is produced by forming the paste on a conductive foil.

(R ¹ and R ^{2 in the} formulas (1) and (2) are each an alkyl group having 1 to 10 carbon atoms and containing at least one fluorine atom, and R ¹ and R ² are They may be the same or different). The non-aqueous electrolyte secondary according to claim 1, wherein the electrode active material is at least one selected from the group consisting of Li ₄ Ti ₅ O ₁₂ , H ₂ Ti ₁₂ O ₂₅ and TiO ₂ (B). A method for producing a negative electrode for a battery. _3. The nonaqueous electrolyte 2 according to claim ^1, wherein R ¹ and R ² in the chiton and diol represented by the formula (1) and the formula (2) are —CF ₃ or —CF ₂ CF _3. The manufacturing method of the negative electrode for secondary batteries. The negative electrode for nonaqueous electrolyte secondary batteries manufactured by the manufacturing method of the negative electrode for nonaqueous electrolyte secondary batteries in any one of Claims 1-3.   The nonaqueous electrolyte secondary battery manufactured using the said negative electrode of Claim 4, a positive electrode, and the nonaqueous electrolyte interposed between the said negative electrode and the said positive electrode.