JP2014192135A - Method of manufacturing positive electrode for lithium ion secondary battery, positive electrode, and lithium ion secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of productively manufacturing a positive electrode for a high quality lithium ion secondary battery showing stable charge and discharge behavior and having excellent cycle characteristics, the positive electrode obtained by the manufacturing method, and a lithium ion secondary battery having the positive electrode for the lithium ion secondary battery.SOLUTION: A method of manufacturing a positive electrode for a lithium ion secondary battery has a mixing process for mixing a positive electrode active material coated with a non-metal material with a binder in a vessel coated with the same material as the non-metal material.

Description

  The present invention relates to a method for producing a positive electrode for a lithium ion secondary battery, a positive electrode for a lithium ion secondary battery obtained by the production method, and a lithium ion secondary battery having the positive electrode for a lithium ion secondary battery.

  With the recent development of electronic technology and increasing interest in environmental technology, various electrochemical devices are used. In particular, there are many requests for energy saving, and expectations for what can contribute to it are increasing. For example, a solar cell is mentioned as a power generation device, and a secondary battery, a capacitor, a capacitor, etc. are mentioned as an electrical storage device. Lithium ion secondary batteries, which are representative examples of power storage devices, have been conventionally used mainly as rechargeable batteries for portable devices, but in recent years, they are also expected to be used as batteries for hybrid vehicles and electric vehicles.

A lithium ion secondary battery generally has a configuration in which a positive electrode and a negative electrode mainly composed of an active material capable of inserting and extracting lithium are arranged via a separator. The positive electrode of the lithium ion secondary battery includes LiCoO ₂ , LiNiO ₂ or LiMn ₂ O ₄ as a positive electrode active material, carbon black or graphite as a conductive agent, and polyvinylidene fluoride, latex or rubber as a binder. Is formed by coating a positive electrode mixture in which is mixed on a positive electrode current collector made of aluminum or the like. The negative electrode is formed by coating a negative electrode mixture made of copper or the like with a negative electrode mixture in which coke or graphite as a negative electrode active material and polyvinylidene fluoride, latex or rubber as a binder are mixed. Is done. The separator is formed by a microporous membrane made of a synthetic resin such as porous polyolefin, and its thickness is very thin, from several μm to several hundred μm. The positive electrode, the negative electrode, and the separator are impregnated with an electrolytic solution in the battery. Examples of the electrolytic solution include an electrolytic solution in which a lithium salt such as LiPF ₆ or LiBF ₄ is dissolved in an aprotic solvent such as propylene carbonate or ethylene carbonate, or a polymer such as polyethylene oxide.

  Currently, lithium ion secondary batteries are mainly used as rechargeable batteries for portable devices (see, for example, Patent Document 1). In recent years, it is expected to be widely used as batteries for automobiles such as hybrid cars and electric cars.

  By the way, if metal impurities are mixed in the positive electrode of the lithium ion secondary battery, the battery characteristics are adversely affected. Therefore, in equipment for manufacturing the positive electrode, the raw material (positive electrode active material) constituting the positive electrode and Measures are taken so that metal impurities are not mixed into the raw material from the contacting part or the part facing the raw material. For example, a stainless steel or a super hard material having excellent wear resistance is used for a portion in contact with the raw material, and stainless steel plating or chrome plating having excellent corrosion resistance is applied to a portion facing the raw material.

  In addition, in a lithium ion secondary battery manufacturing facility that manufactures lithium ion secondary batteries from raw materials, it is possible to manufacture high quality lithium ion secondary batteries by preventing metal impurities from being mixed into the raw materials. At the same time, a lithium ion secondary battery manufacturing facility that can improve productivity has been proposed (see, for example, Patent Document 2).

  On the other hand, it has been proposed to coat a positive electrode active material for the purpose of reducing capacity reduction and improving cycle characteristics (see, for example, Patent Document 3). Battery characteristics are expected to be improved by coating with a combination of metal and / or metalloid elements.

JP 2009-087648 A JP 2000-12003 A Special table 2011-519126 gazette

  However, since Patent Document 2 does not mention using a positive electrode active material coated as a raw material, further improvement in battery performance cannot be expected. Patent Document 3 does not mention a positive electrode active material manufacturing facility for a lithium ion secondary battery, and it cannot be expected to manufacture a high-quality positive electrode for a lithium ion secondary battery with high productivity.

  Therefore, the present invention has been made in view of the above circumstances, and exhibits a stable charge / discharge behavior, good cycle characteristics, and a method for producing a high-quality positive electrode for a lithium ion secondary battery with high productivity. It aims at providing the lithium ion secondary battery which has a positive electrode for lithium ion secondary batteries obtained by a manufacturing method, and this positive electrode for lithium ion secondary batteries.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a container coated with a predetermined nonmetallic material, and the present invention has been completed. It was.

That is, the present invention is as follows.
[1]
A mixing step of mixing a positive electrode active material coated with a nonmetallic material and a binder in a container coated with the same material as the nonmetallic material;
A method for producing a positive electrode for a lithium ion secondary battery.
[2]
The method for producing a positive electrode for a lithium ion secondary battery according to [1] above, wherein the nonmetallic material is ceramic.
[3]
The method for producing a positive electrode for a lithium ion secondary battery according to [2] above, wherein the ceramic is one or more selected from the group consisting of alumina, zirconia, and titania.
[4]
A positive electrode for a lithium ion secondary battery produced by the method for producing a positive electrode for a lithium ion secondary battery according to any one of [1] to [3] above.
[5]
The lithium ion secondary battery which has a positive electrode for lithium ion secondary batteries as described in the preceding clause [4].

  According to the present invention, a method for producing a high-quality positive electrode for a lithium ion secondary battery exhibiting stable charge / discharge behavior, good cycle characteristics, and high quality, and a lithium ion secondary battery obtained by the production method And a lithium ion secondary battery having the positive electrode for a lithium ion secondary battery.

  Hereinafter, a mode for carrying out the present invention (hereinafter, simply referred to as “the present embodiment”) will be described in detail. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention. Deformation is possible.

[Method for producing positive electrode for lithium ion secondary battery]
The method for producing a positive electrode for a lithium ion secondary battery (hereinafter also referred to as “positive electrode”) according to this embodiment is as follows.
A mixing step of mixing a positive electrode active material coated with a nonmetallic material and a binder in a container coated with the same material as the nonmetallic material;

[Mixing process]
The mixing step is a step of mixing the positive electrode active material coated with the nonmetallic material and the binder in a container coated with the same material as the nonmetallic material. In this step, in addition to the positive electrode active material and the binder, a conductive additive, a solvent, and the like may be mixed as necessary.

  The solid content concentration of the mixture obtained in the mixing step is preferably 30 to 80% by mass, more preferably 40 to 70% by mass, and further preferably 45 to 65% by mass. When the solid content concentration is within the above range, a uniform electrode tends to be produced in a short drying time.

  Other steps in the method for producing a positive electrode for a lithium ion secondary battery are not particularly limited, and known steps can be performed. For example, a positive electrode can be produced by applying the obtained mixture to a positive electrode current collector and drying it to form a positive electrode mixture layer and pressurizing it as necessary to adjust the thickness. In addition, although a positive electrode collector is not specifically limited, For example, metal foil, such as aluminum foil or stainless steel foil, is mentioned.

〔container〕
The container used in this embodiment is coated with the same material as the non-metallic material that coats the positive electrode active material. By using such a container, it is possible to prevent the mixing of metal impurities derived from the wear of the container, produce a stable charge / discharge behavior, and produce a positive electrode for a lithium ion secondary battery with excellent cycle characteristics. It can be manufactured with good performance.

  Such a container is not particularly limited. For example, it is preferable that the container is coated with a base made of a material having high mechanical strength. By using such a container, the mechanical strength of the container can be ensured, and there is a tendency to become a method for producing a positive electrode for a lithium ion secondary battery with higher productivity. Although it does not specifically limit as said materials, For example, metal materials, such as plain steel, stainless steel, titanium, are mentioned.

  It is preferable to have a complicated shape (uneven shape) in which the interface where the coating layer and the base abut is engaged. Thereby, a coating layer and a base will be joined firmly and as a result, there exists a tendency for peeling (peeling) of a coating layer to become difficult to occur. Moreover, even if the coating layer is about to change in volume, its deformation can be more firmly regulated, and the coating layer tends to be less likely to be peeled off (stripped). The method for producing the concavo-convex shape is not particularly limited, and examples thereof include changing the drying conditions during production.

  When the container is used for a long time, the metal impurities in the mixture increase, and the capacity of the produced battery is reduced. Therefore, the film thickness of the coating layer is preferably 0.1 to 0.5 mm, more preferably 150 to 450 μm, and further preferably 200 to 400 μm. When the film thickness is in the above range, even when a high shearing force is applied to the container, the metal impurities tend to be prevented from being mixed into the mixture.

[Manufacturing method of container (coating method)]
The method for coating the container with the nonmetallic material is not particularly limited, and examples thereof include plasma spraying, PVD (physical vapor deposition), CVD (chemical vapor deposition), and sol / gel. .

  The above-mentioned plasma spraying method converts an inert gas such as argon into plasma by arc discharge and injects it from a thin nozzle to form a jet of ultra-high temperature and high-speed flow, and feeds the sprayed material powder into the formed jet This is a technique of accelerating this while melting and forming a film on the surface of the substrate. More specifically, a high melting point thin film is formed on the surface of the base material using a non-metallic material such as ceramics as the thermal spray material.

  The PVD method is a method of forming a thin film by heating the solid at a high temperature without causing a chemical reaction or by forcibly evaporating the solid and then condensing it on the surface of the article to be processed. is there. Specific methods of the PVD method are roughly classified into a vacuum deposition method, an ion plating method, a sputtering method, and the like.

  The vacuum vapor deposition method is a method of forming a thin film by heating and evaporating a substance in a vacuum and depositing it in a layer form on the surface of a processed product. This method has an advantage that many substances can be easily formed into a thin film and an advantage that a thin film having a large area can be obtained.

  The ion plating method is a method of forming a thin film on the surface of a processed product by ionizing or exciting evaporated atoms using plasma generated by applying an electric field. This method has the advantages that any vapor deposition material such as metal and oxide can be used, film formation at a low temperature is possible, and high-speed reactive film formation is possible.

  The above sputtering method generates ionized plasma with a relatively low degree of vacuum, accelerates ionized argon to collide with a target (a solid raw material that becomes a target on which accelerated particles collide), and knocks out target atoms. This is a technique for depositing and covering the surface of the product to be processed. This method has an advantage that it is possible to form a film even with a material difficult to be obtained by a vacuum deposition method, such as a refractory metal or an alloy.

  The CVD method is a method of forming a thin film by a chemical reaction in the gas phase of metal vapor or volatile compound vapor. Specific methods of the CVD method are roughly classified into an electric furnace method, a chemical flame method, an electron beam method, a laser method, a plasma method, and the like depending on a heating source for a gas phase reaction.

  The sol-gel method is a method of forming an oxide film by adding a hydrolysis reagent to a metal alkoxide or metal salt solution and subjecting the hydrolysis product to condensation polymerization.

[Positive electrode active material]
The positive electrode active material used in the present embodiment is coated with a nonmetallic material. Hereinafter, the positive electrode active material is also referred to as a “core”, and the coating layer containing a nonmetallic material is also referred to as a “shell”. By using a positive electrode active material coated with a nonmetallic material, capacity reduction is further prevented and cycle characteristics are further improved.

  Such a positive electrode active material is not particularly limited, and examples thereof include metal chalcogenides and metal oxides, composite oxides, olivine-type phosphate compounds, and conductive polymers having a tunnel structure and a layered structure. .

Although it does not specifically limit as a metal chalcogenide and a metal oxide which have a tunnel structure and a layer structure, For example, the lithium containing complex oxide represented by following formula (d) and (e) is mentioned. The metal chalcogenides and metal oxides having such a tunnel structure or a layered structure is not particularly limited, specifically, lithium cobalt oxide represented by _{LiCoO 2; LiMnO 2, LiMn 2} O 4, Li ₂ Lithium manganese oxide typified by Mn ₂ O ₄ ; lithium nickel oxide typified by LiNiO ₂ and the like.
Li _x MO ₂ (d)
Li _y M ₂ O ₄ (e)
(In formulas (d) and (e), M represents one or more metals selected from the group consisting of transition metals, x represents a number from 0 to 1, and y represents a number from 0 to 2.)

Further, the metal chalcogenide and metal oxide are not particularly limited. For example, S, MnO ₂ , FeO ₂ , FeS ₂ , V ₂ O ₅ , V ₆ O ₁₃ , TiO ₂ , TiS ₂ , MoS ₂ and NbSe are used. Examples thereof include oxides of metals other than lithium typified by ₂ .

Moreover, it does not specifically limit as complex oxide, For example, the lithium containing complex metal oxide represented by a following formula is mentioned.
Li _z MO ₂
(Here, M represents two or more elements selected from the group consisting of Ni, Mn, Co, Al and Mg, and z represents a number greater than 0.9 and less than 1.2)

Further, the olivine-type phosphate compound is not particularly limited, and examples thereof include iron phosphate olivine represented by LiFePO ₄ .

  The conductive polymer is not particularly limited, and examples thereof include conductive polymers represented by polyaniline, polythiophene, polyacetylene, and polypyrrole.

  Among these, it is preferable that a lithium containing compound is included as a positive electrode active material. By using a lithium-containing compound, lithium ions can be moved without newly introducing lithium ions from the outside. Further, when a lithium-containing compound is used as the positive electrode active material, a positive electrode capable of obtaining a high voltage and a high energy density tends to be produced.

Such a lithium-containing compound is not particularly limited as long as it contains lithium, and includes, for example, a composite oxide containing lithium and a transition metal element, a metal chalcogenide having lithium, lithium and a transition metal element. Examples thereof include a phosphoric acid compound containing, and a metal silicate compound represented by the following formula containing lithium and a transition metal element.
Li _t M _u SiO ₄
(Here, M represents one or more metals selected from the group consisting of transition metals, t represents a number from 0 to 1, and u represents a number from 0 to 2.)

  From the viewpoint of obtaining a higher voltage, lithium, cobalt (Co), nickel (Ni), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), chromium (Cr), vanadium ( V) and composite oxides containing at least one transition metal element selected from the group consisting of titanium (Ti) and phosphate compounds are preferred.

The lithium-containing compound is not particularly limited, but for example, compounds represented by the following formulas (f) and (g) are preferable.
Li _v M ^I O ₂ (f)
Li _w M ^II PO ₄ (g)
(In formulas (f) and (g), M ^I and M ^II each represent one or more transition metal elements, and the values of v and w vary depending on the charge / discharge state of the battery, but usually v is 0.05 to 1.10, w represents a number from 0.05 to 1.10.

  The compound represented by the above formula (f) generally has a layered structure, and the compound represented by the above formula (g) generally has an olivine structure. In these compounds, for the purpose of stabilizing the structure, a part of the transition metal element is substituted with Al, Mg, other transition metal elements or included in the crystal grain boundary, a part of the oxygen atom And those substituted with a fluorine atom or the like. Furthermore, what coat | covered the other positive electrode active material to at least one part of the positive electrode active material surface is mentioned.

In addition to the above, Li ₂ MnO ₃ —LiMO ₂ solid solution cathode material aimed at high capacity batteries, high voltage compatible Li (Ni _0.5 Mn _1.5 ) O _{4, and the} like can also be cited as cathode active materials.

  A positive electrode active material may be used individually by 1 type, or may use 2 or more types together.

  The number average particle diameter (primary particle diameter) of the positive electrode active material is preferably 0.05 to 100 μm, more preferably 0.5 to 50 μm, and further preferably 1 to 10 μm. The number average particle size of the positive electrode active material was randomly extracted from 100 particles observed with a transmission electron microscope, and image analysis software (for example, image analysis software manufactured by Asahi Kasei Engineering Co., Ltd., trade name “A Image-kun”) It can also be obtained by analyzing the above and calculating the arithmetic mean. In this case, when the number average particle diameter differs between measurement methods for the same sample, a calibration curve created for the standard sample may be used.

[Non-metallic materials]
Although it does not specifically limit as a nonmetallic material, For example, a ceramic, resin, etc. are mentioned. Of these, ceramic is preferable. By using ceramic, it is possible to obtain a chemically stable and hard coating.

  Although it does not specifically limit as said ceramic, For example, it is preferable that the oxide containing the element selected from the group which consists of Al, Ti, and Zr, or these mixtures are included. Although it does not specifically limit as said ceramic, For example, it is preferable that it is 1 or more types selected from the group which consists of an alumina, a zirconia, and a titania. Such a ceramic is an inactive compound with respect to a decomposition product generated by decomposition of an electrolyte generated by charging (oxidation reaction) at a high voltage. By using such a ceramic, there is a tendency to obtain a positive electrode that exhibits more stable charge / discharge behavior and is more excellent in cycle characteristics. Of these, alumina and zirconia are preferable, and alumina is more preferable. By using such a non-metallic material, a more uniform and chemically more stable coating tends to be obtained.

  The number average particle size of the non-metallic material is not particularly limited, but for example, a material having a nano-size number average particle size can be used. The number average particle size of the nonmetallic material is preferably 50 nm or less, more preferably 30 nm or less, and further preferably 5 to 20 nm. When the number average particle diameter of the non-metallic material is 50 nm or less, the coating property on the core tends to be further improved. In addition, when the number average particle diameter of the nonmetallic material is 5 nm or more, aggregation of the nonmetallic materials is suppressed, dispersibility when coating is performed, and a more uniform coating layer tends to be formed. is there. Here, the size (number average particle diameter) of the particles of the nonmetallic material can be obtained by taking a scanning electron microscope (SEM) photograph of the particles and analyzing the obtained SEM photograph. Is possible.

  The coating layer containing a non-metallic material preferably has a nano-sized thickness that can conduct lithium ions and has no resistance. The thickness of the non-metallic material coating layer is preferably 50 nm or less, more preferably 30 nm or less, and further preferably 5 to 20 nm. When the thickness of the coating layer is 50 nm or less, a decrease in the electron transfer rate to the surface of the positive electrode active material constituting the core and the lithium ion transfer rate into the active material is suppressed. It tends to be able to suppress a decrease in chemical characteristics (such as a decrease in high-rate characteristics and a decrease in life characteristics). Moreover, when the thickness of the coating layer is 5 nm or more, there is a tendency to obtain a positive electrode that exhibits stable charge / discharge behavior and is superior in cycle characteristics.

[Method for producing positive electrode active material (coating method on positive electrode active material)]
(Dispersion preparation process)
Hereinafter, the manufacturing method of a positive electrode active material is demonstrated. First, a coating liquid in which nano-sized non-metallic material particles are dispersed is prepared, and a positive electrode active material such as a lithium composite oxide is dispersed in the coating liquid to prepare a dispersion liquid. In the dispersion liquid, the nonmetallic material particles have high surface energy and are unstable, and thus are adsorbed on the surface of the positive electrode active material existing as larger particles in order to maintain a stable state.

  Under the present circumstances, 1-30 mass parts is preferable, for example, 1-20 mass parts is more preferable with respect to 100 mass parts of positive electrode active materials, and 1-10 mass parts is further more preferable. When the amount of the nonmetallic material used is 1 part by mass or more, the effect of forming the coating layer tends to be more excellent. Moreover, when the usage-amount of a nonmetallic material is 30 mass parts or less, a thin coating film is formed in the positive electrode active material surface, and it exists in the tendency for the increase in resistance of an electrode to be suppressed more.

  The solid content concentration of the positive electrode active material in the dispersion is preferably 1 to 20 g, more preferably 1 to 15 g, and even more preferably 1 to 10 g per 1000 ml of the solvent. When the solid content concentration is within the above range, the uniformity tends to be excellent.

  Although the solvent used for a dispersion liquid is not specifically limited, For example, 1 or more types selected from the group which consists of water, methanol, ethanol, propanol, and N-methyl-2-pyrrolidone is mentioned.

  In order to facilitate the dispersion of the positive electrode active material in the dispersion, additives such as a dispersant and a surfactant may be further used. The type and content of such additives are in accordance with known techniques in this field. These additives tend to stabilize the surface of the nano-sized non-metallic material. The upper limit of the amount used is preferably within a range that does not interfere with physical adsorption of the nonmetallic material to the surface of the positive electrode active material.

(Volatile heat treatment process)
Next, after evaporating the solvent in the produced dispersion, heat treatment is performed to obtain a positive electrode oxide coated with a nonmetallic material. Although the temperature at the time of volatilization can be suitably adjusted according to the kind of solvent of a dispersion liquid, 40-100 degreeC is preferable, for example, 50-100 degreeC is more preferable, and 60-100 degreeC is further preferable. When the temperature of the volatilization process is 50 ° C. or higher, the volatilization time tends to be shortened. Moreover, when the temperature of the volatilization step is 100 ° C. or lower, the production method tends to be excellent in economic efficiency.

  Moreover, 300-700 degreeC is preferable, as for heat processing temperature, 350-650 degreeC is more preferable, and 400-600 degreeC is further more preferable. When the heat treatment temperature is 300 ° C. or higher, it tends to be possible to suppress impurities from remaining in the positive electrode active material. Moreover, it exists in the tendency for it to become a manufacturing method excellent in economical efficiency by being 600 degrees C or less.

[Lithium ion secondary battery]
The lithium ion secondary battery which concerns on this embodiment has the positive electrode for lithium ion secondary batteries manufactured by the manufacturing method of the said positive electrode for lithium ion secondary batteries. The lithium ion secondary battery is not particularly limited as long as it has the positive electrode, and can further include a negative electrode, a separator, an electrolyte, and an outer package.

[Positive electrode]
The positive electrode for a lithium ion secondary battery according to this embodiment is manufactured by the method for manufacturing a positive electrode for a lithium ion secondary battery.

[Negative electrode]
In the lithium ion secondary battery according to the present embodiment, the negative electrode can include a negative electrode active material and, if necessary, a conductive additive or a binder. In the present embodiment, a battery employing metallic lithium as the negative electrode active material is also included in the lithium ion secondary battery.

  Although it does not specifically limit as a negative electrode active material, For example, the material which can occlude and discharge | release lithium ion and 1 or more types of materials chosen from the group which consists of metallic lithium are used. Among these, metallic lithium; and one kind selected from the group consisting of carbon materials, materials containing elements capable of forming alloys with lithium, and materials capable of inserting and extracting thium ions such as lithium-containing compounds It is preferable to contain the above materials.

  The carbon material is not particularly limited, for example, hard carbon, soft carbon, artificial graphite, natural graphite, graphite, pyrolytic carbon, coke, glassy carbon, organic polymer compound fired body, mesocarbon microbeads, Examples thereof include carbon fiber, activated carbon, graphite, carbon colloid, and carbon black.

  Among these, the coke is not particularly limited, and examples thereof include pitch coke, needle coke, and petroleum coke.

  Further, the fired body of the organic polymer compound is not particularly limited, and examples thereof include a material obtained by firing and carbonizing a polymer material such as a phenol resin or a furan resin at an appropriate temperature.

  The material containing an element capable of forming an alloy with lithium is not particularly limited. For example, a metal simple substance, a metalloid simple substance, an alloy thereof, a compound thereof, or one or more phases thereof. And a compound having at least a part thereof.

  Such metal elements and metalloid elements are not particularly limited. For example, titanium (Ti), tin (Sn), lead (Pb), aluminum, indium (In), silicon (Si), zinc (Zn) , Antimony (Sb), bismuth (Bi), gallium (Ga), germanium (Ge), arsenic (As), silver (Ag), hafnium (Hf), zirconium (Zr) and yttrium (Y). Among these, metal elements and metalloid elements of Group 4 or Group 14 in the long-period periodic table are preferable, and titanium, tin, and silicon are particularly preferable.

As an alloy of titanium is not particularly limited, examples thereof include TiS _2.

  Although it does not specifically limit as an alloy of tin, For example, as a 2nd element other than tin, silicon, magnesium (Mg), nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium (Ti) , One having at least one element selected from the group consisting of germanium, bismuth, antimony and chromium (Cr).

  The silicon alloy is not particularly limited. For example, as the second constituent element other than silicon, tin, magnesium, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony And one having at least one element selected from the group consisting of chromium.

  The titanium compound, the tin compound, and the silicon compound are not particularly limited, and examples thereof include those having oxygen (O) or carbon (C). In addition to titanium, tin, or silicon, the second compound described above is used. It may have a constituent element.

  In the present specification, the “alloy” includes, in addition to an alloy composed of two or more metal elements, an alloy composed of one or more metal elements and one or more metalloid elements. Further, the “alloy” may have a nonmetallic element as long as it has metal properties as a whole. In the structure of the alloy, a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or two or more of these may coexist.

  Although it does not specifically limit as said lithium containing compound, For example, the same thing as what was illustrated as a positive electrode material can be used.

  The said negative electrode active material may be used individually by 1 type, or may use 2 or more types together.

  The number average particle diameter (primary particle diameter) of the negative electrode active material is preferably 0.1 to 100 μm, more preferably 1 to 10 μm. The number average particle diameter of the negative electrode active material can be measured by the same method as the number average particle diameter of the positive electrode active material.

  A negative electrode is obtained as follows, for example. That is, first, a negative electrode mixture-containing paste is prepared by dispersing, in a solvent, a negative electrode mixture prepared by adding a conductive additive or a binder to the negative electrode active material, if necessary. Next, the negative electrode mixture-containing paste is applied to a negative electrode current collector and dried to form a negative electrode mixture layer, which is pressurized as necessary to adjust the thickness, whereby a negative electrode can be produced. .

  Here, the solid content concentration in the negative electrode mixture-containing paste is preferably 30 to 80% by mass, and more preferably 40 to 70% by mass.

  Although a negative electrode collector is not specifically limited, For example, metal foil, such as copper foil, nickel foil, or stainless steel foil, is mentioned.

  In the production of the positive electrode and the negative electrode, the conductive aid used as necessary is not particularly limited, and examples thereof include carbon black typified by graphite, acetylene black and ketjen black; and carbon fibers. The number average particle diameter (primary particle diameter) of the conductive assistant is preferably 0.1 to 100 μm, more preferably 1 to 10 μm. The number average particle size of the conductive additive is measured in the same manner as the number average particle size of the positive electrode active material.

  In addition, the binder used as necessary in producing the positive electrode and the negative electrode is not particularly limited. For example, polyvinylidene fluoride (PVDF), a copolymer containing polyvinylidene fluoride, polytetrafluoroethylene (PTFE) ), Polyacrylic acid, styrene butadiene rubber and fluoro rubber.

[Electrolyte]
The electrolytic solution that can be used in the present embodiment contains a non-aqueous solvent and a lithium salt, a carbonic acid ester having a carbon-carbon double bond (hereinafter also referred to as “C═C bond”), and a cyclic structure having a fluorine atom. Preferably, it further contains at least one compound selected from the group consisting of carbonate (hereinafter also referred to as “fluorinated cyclic carbonate”) and sulfone.

  Although it does not specifically limit as said non-aqueous solvent, For example, an aprotic solvent is mentioned. By using an aprotic polar solvent, the ionization degree of the lithium salt, which is an electrolyte that contributes to charge and discharge, tends to be further increased. The aprotic solvent is not particularly limited, and examples thereof include ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, trans-2,3-butylene carbonate, cis-2,3-butylene carbonate, and 1,2-pentylene. Cyclic carbonates typified by lencarbonate, trans-2,3-pentylene carbonate, cis-2,3-pentylene carbonate, trifluoromethylethylene carbonate, fluoroethylene carbonate and 4,5-difluoroethylene carbonate; γ-butyrolactone And lactones represented by γ-valerolactone; cyclic ethers represented by tetrahydrofuran and dioxane; methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate, methyl propyl carbonate Nate, methyl isopropyl carbonate, dipropyl carbonate, methyl butyl carbonate, dibutyl carbonate, ethyl propyl carbonate and chain carbonate represented by methyl trifluoroethyl carbonate; nitrile represented by acetonitrile; chain ether represented by dimethyl ether; Examples thereof include a chain carboxylic acid ester represented by methyl propionate; a chain ether carbonate compound represented by dimethoxyethane. These are used singly or in combination of two or more.

  The non-aqueous solvent preferably contains one or more cyclic aprotic polar solvents, and more preferably contains one or more cyclic carbonates typified by ethylene carbonate and propylene carbonate. By using such a non-aqueous solvent, the ionization degree of the lithium salt tends to be higher.

  An ionic liquid can also be used as the non-aqueous solvent. An ionic liquid is a liquid composed of ions obtained by combining an organic cation and an anion.

  The organic cation is not particularly limited, and examples thereof include imidazolium ions such as dialkylimidazolium cation and trialkylimidazolium cation; tetraalkylammonium ion, alkylpyridinium ion, dialkylpyrrolidinium ion, and dialkylpiperidinium ion.

The anion serving as a counter for these organic cations is not particularly limited. For example, PF ₆ anion, PF ₃ (C ₂ F ₅ ) ₃ anion, PF ₃ (CF ₃ ) ₃ anion, BF ₄ anion, BF ₂ ( CF ₃ ) ₂ anion, BF ₃ (CF ₃ ) anion, bisoxalatoborate anion, Tf (trifluoromethanesulfonyl) anion, Nf (nonafluorobutanesulfonyl) anion, bis (fluorosulfonyl) imide anion, bis (trifluoromethanesulfonyl) ) Imide anion, bis (pentafluoroethanesulfonyl) imide anion, and dicyanoamine anion.

  The electrolytic solution according to the present embodiment may contain at least one of a carbonic acid ester having a C═C bond and a fluorinated cyclic carbonate. By containing at least one of a carbonic acid ester having a C═C bond and a fluorine-containing cyclic carbonate, a protective film is formed on the negative electrode, and the decomposition reaction of the electrolytic solution accompanying a cycle test or the like can be suppressed. Moreover, it can replace with those compounds, or can show | play the same effect even if it uses a sulfone. Hereinafter, these compounds are also simply referred to as “additives”.

  Examples of the carbonic acid ester having a C═C bond include a cyclic carbonic acid ester and a chain carbonic acid ester. Although it does not specifically limit as cyclic carbonate which has a C = C bond, For example, unsaturated cyclic carbonates, such as vinylene carbonate (VC); and C2-C4 alkenyls, such as vinyl ethylene carbonate and divinyl ethylene carbonate And cyclic carbonate having a group as a substituent. Among these, vinylene carbonate is preferable. By using such a cyclic carbonate having a C═C bond, the obtained battery performance tends to be further improved.

  The chain carbonate having a C═C bond is not particularly limited, and examples thereof include vinyl acetate, vinyl butyrate, vinyl hexanate, and the like, and among these, vinyl acetate is preferable. By using such a chain carbonate having a C═C bond, the obtained battery performance tends to be further improved.

  The fluorine-containing cyclic carbonate is not particularly limited as long as it is a cyclic carbonate having a fluorine atom in the molecule. For example, monofluoroethylene carbonate (FEC), 1,2-difluoroethylene carbonate, 1,2,3-trifluoro Fluorine containing 1 to 6 fluorine atoms such as propylene carbonate, 2,3-difluoro-2,3-butylene carbonate, 1,1,1,4,4,4-hexafluoro-2,3-butylene carbonate A cyclic carbonate is mentioned. Among these, monofluoroethylene carbonate (FEC) is preferable. By using such a fluorine-containing cyclic carbonate, the viscosity and the solubility of the lithium salt tend to be more excellent.

The sulfone is a compound having a sulfonyl group (—SO ₂ —) bonded to two carbon atoms in the molecule. Specific examples thereof include, but are not limited to, for example, two alkyl groups such as sulfolane, 2-methylsulfolane, 3-methylsulfolane, dimethylsulfone, diethylsulfone, dipropylsulfone, methylethylsulfone, and methylpropylsulfone. And compounds having a sulfonyl group bonded to. Of these, sulfolane is preferred. By using such a sulfone, the obtained battery performance tends to be further improved.

  When an additive is contained in the electrolytic solution, the carbonic acid ester having a C═C bond, the fluorine-containing cyclic carbonate, and the sulfone are used singly or in combination of two or more. It is preferable that the content rate of these compounds is 1-30 mass% with respect to the amount of electrolyte solution in the sum total. When the content of these compounds is 1% by mass or more, it is possible to form a protective film more fully on the negative electrode, and when the content is 30% by mass or less, an increase in film resistance due to the protective film is suppressed. Thus, the charge / discharge characteristics can be further prevented from being deteriorated. From such a viewpoint, the content of these compounds is more preferably 1 to 25% by mass.

Specific examples of the lithium salt used as the electrolyte is not particularly limited, for _{example, LiPF 6, LiBF 4, LiClO} 4, LiAsF 6, Li 2 SiF 6, LiOSO 2 C k F 2k + 1 [k 1-8 Integer], LiN (SO ₂ C _k F _{2k + 1} ) ₂ [k is an integer of 1 to 8], LiPF _n (C _k F _{2k + 1} ) _6-n [n is an integer of 1 to 5, k is 1-8], LiBF _n ((C _k F _{2k + 1} ) _4-n [n is an integer of 1-3, k is an integer of 1-8], LiB (C ₂ O ₂ ) ₂ Lithium bisoxalyl borate, lithium difluorooxalylborate represented by LiBF ₂ (C ₂ O ₂ ), and lithium trifluorooxalyl phosphate represented by LiPF ₃ (C ₂ O ₂ ).

Moreover, the lithium salt represented by the following formula (a), (b) or (c) can also be used as the electrolyte.
LiC (SO ₂ R ¹¹ ) (SO ₂ R ¹² ) (SO ₂ R ¹³ ) (a)
LiN (SO ₂ OR ¹⁴ ) (SO ₂ OR ¹⁵ ) (b)
LiN (SO ₂ R ¹⁶ ) (SO ₂ OR ¹⁷ ) (c)
(In the formula (a), (b) or (c), R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ may be the same or different from each other, and A perfluoroalkyl group of formula 1-8 is shown.)

These electrolytes are used singly or in combination of two or more. Among these electrolytes, LiPF ₆ , LiBF ₄ and LiN (SO ₂ C _k F _{2k + 1} ) ₂ [k is an integer of 1 to 8] are preferable from the viewpoint of battery characteristics and stability.

  Although the density | concentration of the electrolyte in electrolyte solution is arbitrary and is not specifically limited, Preferably it is 0.1-3 mol / L, More preferably, it is 0.5-2 mol / L.

  In addition, the lithium ion secondary battery obtained by using the electrolyte solution tends to be superior in safety and battery characteristics.

[Separator]
The lithium ion secondary battery of this embodiment preferably includes a separator between the positive electrode and the negative electrode from the viewpoint of providing safety such as prevention of short circuit between the positive and negative electrodes and shutdown. As a separator, the thing similar to what is equipped with a well-known lithium ion secondary battery can be used. Among these, an insulating thin film having high ion permeability and excellent mechanical strength is preferable.

  Such a separator is not particularly limited, and examples thereof include a woven fabric, a nonwoven fabric, and a synthetic resin microporous membrane. Among these, a synthetic resin microporous membrane is preferable. The microporous membrane made of a synthetic resin is not particularly limited, and examples thereof include a microporous membrane containing polyethylene or polypropylene as a main component, or a polyolefin microporous membrane such as a microporous membrane containing both of these polyolefins. It is done. Moreover, it is although it does not specifically limit as a nonwoven fabric, For example, the porous film made from a product made from a ceramic, the product made from polyolefin, the product made from polyester, the product made from polyamide, the product made from liquid crystal polyester, the product made from aramid, and a heat resistant resin is mentioned, for example.

  The separator may be a single microporous membrane or a laminate of a plurality of microporous membranes, or may be a laminate of two or more microporous membranes.

  The separator may be a separator whose surface is coated with inorganic particles.

[Exterior body]
The lithium ion secondary battery of the present embodiment includes a separator, a positive electrode and a negative electrode that sandwich the separator from both sides, a positive electrode current collector (disposed outside the positive electrode) that sandwiches the laminate, and a negative electrode current collector ( Arranged outside the negative electrode) and an exterior body for housing them. A laminate in which the positive electrode, the separator, and the negative electrode are laminated is impregnated with the above-described electrolyte solution. As each of these members, if the electrolyte solution and the separator are combined as described above, other members can be those provided in a conventional lithium ion secondary battery, for example, those described above. Also good.

[Production method of lithium ion secondary battery]
The lithium ion secondary battery of the present embodiment may be the same as the conventional one except that it has the above-described configuration. By using the above-described separator, electrolytic solution, positive electrode, and negative electrode, a known method may be used. Produced. For example, a plurality of positive electrodes in which a positive electrode and a negative electrode are wound in a laminated state with a separator interposed therebetween to be formed into a laminated structure of a wound structure, or are alternately laminated by bending or laminating a plurality of layers. Or a laminate in which a separator is interposed between the electrode and the negative electrode. Next, the laminated body is accommodated in a battery case (exterior), an electrolytic solution is injected into the case, and the laminated body is immersed in the electrolytic solution and sealed, thereby recharging the lithium ion secondary of the present embodiment. A battery can be fabricated. The shape of the lithium ion secondary battery of the present embodiment is not particularly limited, and for example, a cylindrical shape, an elliptical shape, a rectangular tube shape, a button shape, a coin shape, a flat shape, and a laminate shape are suitably employed.

  Since the electrolytic solution used in the present embodiment can achieve high conductivity, the lithium ion secondary battery including the electrolytic solution and the separator described above has high battery characteristics (for example, charge / discharge characteristics, low temperature operability, high temperature). Durability, etc.).

  In the lithium ion secondary battery according to this embodiment, the discharge capacity maintenance rate when the charge / discharge cycle test at 25 ° C. is performed 100 cycles is preferably 80% or more, and more preferably 85% or more. Preferably, it is 90% or more. In the present embodiment, the charge / discharge cycle test refers to the test described in the examples, and indicates a case where both charge and discharge of the manufactured battery are performed under 1C conditions. When the battery is charged and discharged once, it is counted as one cycle, and the discharge capacity maintenance rate is calculated with the discharge capacity at the second cycle as 100%.

[Use]
A positive electrode manufactured by the method for manufacturing a positive electrode for a lithium ion secondary battery according to the present embodiment, and a lithium ion secondary battery including the positive electrode include, for example, a hybrid vehicle, a plug in addition to a portable device such as a mobile phone, a portable audio device, and a personal computer It can be suitably used for rechargeable batteries for automobiles such as in-hybrid cars and electric cars.

  Hereinafter, the present embodiment will be described in more detail by way of examples. However, the present embodiment is not limited to these examples. In addition, the measuring method and evaluation method of various physical properties and characteristics are as follows.

(1) Impurity measurement In the examples and comparative examples, the positive electrode active material and the binder were mixed in a container continuously for 6 months, and the amount of Fe component contained in the mixture after 6 months was determined using an ICP device (Perkin Elmer). Quantitative analysis was performed. It is shown that the amount of Fe component in the mixture increases with time in the case of using the container coated with the nonmetallic material than in the case of using the container not coated with the nonmetallic material. It was.

(2) Capacity maintenance rate measurement of lithium ion secondary battery (cycle characteristics)
The charge capacity and discharge capacity at a specific charge current and discharge current were measured as follows to evaluate the charge / discharge characteristics of the lithium ion secondary battery.
As described in detail in Example 1, a small battery with 1C = 3 mA was prepared and used as a lithium ion secondary battery for measurement. The charge and discharge capacity of the lithium ion secondary battery was measured using a charge / discharge device ACD-01 (trade name) manufactured by Asuka Electronics Co., Ltd. and a thermostat PLM-63S (trade name) manufactured by Futaba Kagaku Co., Ltd.

  The battery was charged at a constant current of 1 mA, and after reaching 4.2 V, charging was performed for a total of 8 hours by controlling the current value so as to hold 4.2 V. Thereafter, after 10 minutes of rest, the battery was discharged to 3.0 V at 1 mA.

  Subsequently, charging was performed at a constant current of 3 mA, and after reaching 4.2 V, charging was performed for a total of 3 hours by controlling the current value so as to hold 4.2 V. After 10 minutes of rest, the battery was discharged at 3 mA to 3.0 V, and the discharge capacity at that time was 1 C discharge capacity (mAh). The battery ambient temperature at this time was set to 25 ° C. In the charge / discharge cycle test, the ambient temperature of the battery was set to 50 ° C.

  First, in the first cycle, the battery was charged with a constant current of 3 mA, and after reaching 4.2 V, charging was performed at a constant voltage of 4.2 V for a total of 3 hours. Then, after 10 minutes of rest, the battery was discharged at a constant current of 1 mA, and when it reached 3.0 V, it was rested again for 10 minutes. Subsequently, after the second cycle, the battery was charged with a constant current of 3 mA, and after reaching 4.2 V, the battery was charged with a constant voltage of 4.2 V for a total of 3 hours. Thereafter, after 10 minutes of rest, the battery was discharged at a constant current of 3 mA, and when it reached 3.0 V, it was rested again for 10 minutes. Charging and discharging were performed once each as one cycle, and 100 cycles of charging and discharging were performed. The ratio of the discharge capacity at the 100th cycle when the discharge capacity at the second cycle was 100% was taken as the capacity retention rate.

[Example 1]
[Production of positive electrode]
(Production of positive electrode active material coated with non-metallic material)
The dispersion was sonicated for 1 hour in ethanol of alumina having a number average particle size of 12 nm to prepare a coating solution. This coating solution is put in a 0.2 mm thick alumina coated SUS container by a plasma spraying method, and LiMn ₂ O ₄ having a number average particle diameter of 11 μm is dispersed therein as a positive electrode active material. Manufactured. At this time, the amount of alumina contained in the coating solution, with respect to LiMn ₂ O ₄ 100 parts by weight, it was 1 part by mass. The dispersion was heated at 60 ° C. to volatilize ethanol, and then heat treated at a temperature of 450 ° C. to produce a positive electrode active material coated with 20 nm thick alumina.

(Slurry production process)
In a SUS container coated with alumina having a thickness of 0.2 mm by a plasma spraying method, the positive electrode active material coated with alumina and graphite carbon powder having a number average particle size of 6.5 μm as a conductive auxiliary agent (manufactured by Timcal) ) And an acetylene black powder (manufactured by Denki Kagaku Kogyo Co., Ltd.) having a number average particle size of 48 nm and polyvinylidene fluoride (manufactured by Kureha Co., hereinafter also referred to as “PVDF”) as a binder, positive electrode active material: graphite carbon powder: Acetylene black powder: PVDF was mixed at a mass ratio of 100: 4.2: 1.8: 4.6. To the obtained mixture, N-methyl-2-pyrrolidone was added so as to have a solid content of 68% by mass and further mixed to prepare a slurry-like solution.

  This slurry was applied to one side of an aluminum foil having a thickness of 20 μm, and the solvent was dried and removed, followed by rolling with a roll press. The rolled product was punched into a disk shape having a diameter of 16 mm to obtain a positive electrode.

(Production of negative electrode)
Graphite carbon powder (III) (manufactured by Timcal) having a number average particle size of 12.7 μm and graphite carbon powder (IV) (manufactured by Timcar) having a number average particle size of 6.5 μm as a negative electrode active material, and a carboxymethyl cellulose solution as a binder (Solid content concentration 1.83% by mass, manufactured by Daicel) and diene rubber (glass transition temperature: −5 ° C., number average particle size upon drying: 120 nm, dispersion medium: water, solid content concentration 40% by mass, Asahi Kasei Chemicals Co., Ltd.) and graphite carbon powder (III): graphite carbon powder (IV): carboxymethylcellulose solution: diene rubber = 90: 10: 1.44: 1.76 A slurry-like solution was prepared by mixing so that the partial concentration was 45% by mass. The slurry solution was applied to one side of a 10 μm thick copper foil, and the solvent was removed by drying, followed by rolling with a roll press. The rolled product was punched into a disk shape having a diameter of 16 mm to obtain a negative electrode.

[Separator]
A polyethylene microporous separator (Asahi Kasei E-Materials) having an average pore diameter of 0.1 μm, a film thickness of 20 μm and a porosity of 47% was used.

(Preparation of electrolyte)
Vinylene carbonate is added to a mixed solvent of ethylene carbonate: ethyl methyl carbonate = 1: 2 (volume ratio) so as to be 5% by mass with respect to 100% by mass of the electrolytic solution, and LiPF ₆ is added at a concentration of 1.0 mol as a solute. / L was dissolved to prepare an electrolytic solution.

[Assembly and evaluation of lithium ion secondary battery]
The negative electrode, the separator, and the positive electrode were stacked in this order so that the active material surfaces of the positive electrode and the negative electrode were opposed to each other, and stored in a stainless steel container with a lid. The container and the lid were insulated, and the container was accommodated in contact with the negative electrode copper foil and the lid in contact with the positive electrode aluminum foil. The electrolytic solution was poured into the container and sealed to obtain a lithium ion secondary battery.

  The lithium ion secondary battery assembled as described above was evaluated as described in (1) Impurity measurement and (2) Capacity maintenance rate measurement (cycle characteristics) of the lithium ion secondary battery. The results are shown in Table 1 (the same applies hereinafter).

[Example 2]
Other than using a SUS container coated with titania having a thickness of 0.2 mm by plasma spraying and a positive electrode active material (LiMn ₂ O ₄ ) coated with titania having a number average particle size of 13 nm. The same operation as in Example 1 was performed to obtain a positive electrode. Using this positive electrode, the same operation as in Example 1 was performed to assemble and evaluate a lithium ion secondary battery. The titania coating layer of the positive electrode active material was 19 nm thick.

[Example 3]
Implemented except using a SUS container coated with 0.2 mm thick zirconia by plasma spraying and a positive electrode active material (LiMn ₂ O ₄ ) coated with zirconia having a number average particle size of 14 nm. The same operation as in Example 1 was performed to obtain a positive electrode. Using this positive electrode, the same operation as in Example 1 was performed to assemble and evaluate a lithium ion secondary battery. The zirconia coating layer of the positive electrode active material had a thickness of 20 nm.

[Example 4]
A positive electrode was obtained in the same manner as in Example 1 except that Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ was used as the positive electrode active material instead of LiMn ₂ O ₄ . Using this positive electrode, the same operation as in Example 1 was performed to assemble and evaluate a lithium ion secondary battery. In addition, the alumina coating layer of the positive electrode active material had a thickness of 18 nm.

[Example 5]
A positive electrode was obtained in the same manner as in Example 2, except that Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ was used as the positive electrode active material instead of LiMn ₂ O ₄ . Using this positive electrode, the same operation as in Example 1 was performed to assemble and evaluate a lithium ion secondary battery. The titania coating layer of the positive electrode active material was 19 nm thick.

[Example 6]
A positive electrode was obtained in the same manner as in Example 3 except that Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ was used as the positive electrode active material instead of LiMn ₂ O ₄ . Using this positive electrode, the same operation as in Example 1 was performed to assemble and evaluate a lithium ion secondary battery. Note that the zirconia coating layer of the positive electrode active material had a thickness of 19 nm.

[Comparative Example 1]
A positive electrode was obtained in the same manner as in Example 1 except that an uncoated SUS container and an uncoated positive electrode active material (LiMn ₂ O ₄ ) were used. Using this positive electrode, the same operation as in Example 1 was performed to assemble and evaluate a lithium ion secondary battery.

[Comparative Example 2]
A positive electrode was obtained in the same manner as in Comparative Example 1 except that Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ was used as the positive electrode active material instead of LiMn ₂ O ₄ . Using this positive electrode, the same operation as in Example 1 was performed to assemble and evaluate a lithium ion secondary battery.

[Comparative Example 3]
A positive electrode was obtained in the same manner as in Example 1, except that an uncoated SUS container was used. Using this positive electrode, the same operation as in Example 1 was performed to assemble and evaluate a lithium ion secondary battery.

[Comparative Example 4]
A positive electrode was obtained in the same manner as in Example 4 except that an uncoated SUS container was used. Using this positive electrode, the same operation as in Example 1 was performed to assemble and evaluate a lithium ion secondary battery.

[Comparative Example 5]
A positive electrode was obtained in the same manner as in Example 1 except that an uncoated positive electrode active material (LiMn ₂ O ₄ ) was used. Using this positive electrode, the same operation as in Example 1 was performed to assemble and evaluate a lithium ion secondary battery.

[Comparative Example 6]
A positive electrode was obtained in the same manner as in Example 4 except that an uncoated positive electrode active material (Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ ) was used. Using this positive electrode, the same operation as in Example 1 was performed to assemble and evaluate a lithium ion secondary battery.

  As shown in Table 1, the lithium secondary battery using the positive electrode active material for a lithium secondary battery of the present embodiment exhibits stable charge / discharge behavior without being affected by the battery performance due to impurities, and cycle characteristics It turned out to be excellent.

  The method for producing a positive electrode for a lithium ion secondary battery according to the present invention includes, for example, a positive electrode for a rechargeable battery for an automobile such as a hybrid vehicle, a plug-in hybrid vehicle, and an electric vehicle, in addition to a portable device such as a mobile phone, a portable audio, and a personal computer. Industrial applicability as a method of manufacturing

Claims (5)

A mixing step of mixing a positive electrode active material coated with a nonmetallic material and a binder in a container coated with the same material as the nonmetallic material;
A method for producing a positive electrode for a lithium ion secondary battery.   The manufacturing method of the positive electrode for lithium ion secondary batteries of Claim 1 whose said nonmetallic material is a ceramic.   The manufacturing method of the positive electrode for lithium ion secondary batteries of Claim 2 whose said ceramic is 1 or more types selected from the group which consists of an alumina, a zirconia, and a titania.   The positive electrode for lithium ion secondary batteries manufactured by the manufacturing method of the positive electrode for lithium ion secondary batteries of any one of Claims 1-3.   The lithium ion secondary battery which has a positive electrode for lithium ion secondary batteries of Claim 4.