JP2008277265A - Lithium transition metal composite oxide for lithium ion secondary battery positive electrode active material, method for producing lithium transition metal composite oxide, positive electrode active material for lithium ion secondary battery, and lithium ion secondary battery - Google Patents

Abstract

An object of the present invention is to provide a lithium transition metal composite oxide for a positive electrode active material of a lithium ion secondary battery capable of imparting excellent performance to the lithium ion secondary battery and a method for producing the same. Another object of the present invention is to provide a method for producing a lithium transition metal composite oxide, in which the fired powder is less likely to adhere to the fired container and is industrially advantageous.
A lithium transition metal composite oxide for a positive electrode active material for a lithium ion secondary battery, wherein the silicon atom content is 100 to 1000 ppm and the fluorine atom content is 300 to 900 ppm. Lithium compound, transition metal compound, fluorine compound and silicon compound are mixed to obtain a raw material mixture, and then the raw material mixture is fired to obtain a lithium transition metal composite oxide. Manufacturing method.
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Description

  The present invention relates to a lithium ion secondary battery having excellent cycle characteristics, a lithium transition metal composite oxide for a positive electrode active material for a lithium ion secondary battery used in the production of the lithium ion secondary battery, and a positive electrode active for a lithium ion secondary battery. The present invention relates to a material and a method for producing a lithium transition metal composite oxide.

  In recent years, as home appliances have become portable and cordless, lithium ion secondary batteries have been put to practical use as power sources for small electronic devices such as laptop computers, mobile phones, and video cameras. As for this lithium ion secondary battery, since 1980, when Mizushima et al. Reported that lithium cobalt oxide was useful as a positive electrode active material of the lithium ion secondary battery (Non-patent Document 1), the lithium transition metal composite Research and development on oxides has been actively promoted, and many proposals have been made so far.

As the lithium transition metal composite oxide, LiCoO ₂ , LiNiO ₂ , LiMn ₂ O _{4 and the} like are preferably used. In particular, LiCoO ₂ is widely used from the aspects of safety and charge / discharge capacity.

  In particular, a lithium ion secondary battery obtained by using fluorine-containing lithium cobalt oxide in which fluorine is contained in lithium cobalt oxide as a positive electrode active material is excellent in discharge capacity, cycle characteristics, and the like. For example, Japanese Patent Laying-Open No. 2003-221235 (Patent Document 1) discloses a lithium cobalt composite oxide containing 0.025 to 2.5 wt% of F atoms.

  By the way, as a method for producing fluorine-containing lithium cobalt oxide, a method of causing a gaseous fluorine compound to act on the synthesized lithium cobaltate, a method of synthesizing by a solid phase synthesis using a fluorine compound as a raw material, and the like have been proposed. Yes.

  However, as a method for producing fluorine-containing lithium cobalt oxide, when a lithium compound, a cobalt compound and a fluorine compound are mixed and filled in a mullite firing container and fired, the fired powder is applied to the contact surface of the firing container. There was a problem that the powder was fixed and the fired powder could not be discharged from the fired container.

In view of such problems, in Japanese Patent Application Laid-Open No. 2004-281163 (Patent Document 1), using a firing container provided with a dense ceramic coating layer having a silicon content of less than 5% on the inner surface of the firing container, A method of performing firing has been proposed.
JP 2003-221235 A JP 2004-281163 A “Material Research Bulletin” vol. 15, p. 783-789, 1980

  However, due to the demand for improving the performance of lithium ion secondary batteries in recent years, even for lithium ion secondary batteries obtained using the fluorine-containing lithium cobalt oxide of Patent Document 1, The performance was insufficient, and in particular, the cycle characteristics were low. In addition, in this invention, cycling characteristics are the capacity | capacitance maintenance factor, discharge voltage maintenance factor, discharge electric energy maintenance factor, etc. of a lithium ion secondary battery when charging / discharging is repeated.

  Further, in the production method of Patent Document 2, a significant increase in the cost of the firing container is unavoidable due to the ceramic coating, and when the firing container is repeatedly used, the ceramic coating layer is repeatedly peeled and consumed due to repeated use. Since the problem of sticking of the fired powder reoccurs, the fired container must be frequently replaced, which is not industrial.

  Accordingly, an object of the present invention is to provide a lithium transition metal composite oxide for a positive electrode active material for a lithium ion secondary battery that can impart excellent performance to a lithium ion secondary battery, in particular, can improve cycle characteristics. Another object of the present invention is to provide a positive electrode active material for a lithium ion secondary battery and a lithium ion secondary battery obtained by using the same, and a manufacturing method thereof. Another object of the present invention is to provide a method for producing a lithium transition metal composite oxide, in which the fired powder is less likely to adhere to the fired container and is industrially advantageous.

  As a result of intensive studies to solve the above-described problems in the prior art, the present inventors have (1) lithium ion by adding fluorine and silicon in a specific ratio to a lithium transition metal composite oxide. The cycle characteristics of the secondary battery can be improved, the battery safety can be prevented from being lowered due to gas generation, etc., and the gelation of the paint during electrode application can be prevented. (2) Lithium compounds, transition metal compounds and fluorine When the raw material mixture of the compound is fired to produce a lithium transition metal composite oxide, a silicon compound is further mixed into the raw material mixture, and the mixing ratio of the fluorine compound and the silicon compound is set to a specific range. As a result, even if firing is performed using a mullite firing container, the lithium transition metal composite oxide powder (hereinafter referred to as the raw material mixture) is a fired product of the raw material mixture. Lithium transition metal composite oxide powder, which is a fired product, is also referred to as fired powder.) Can be made difficult to adhere to the firing container, and the cycle characteristics of the lithium ion secondary battery can be improved. And it discovered that the amount of residual alkali components of lithium transition metal complex oxide could be made low, etc., and came to complete this invention.

  That is, the present invention (1) is a lithium transition for a positive electrode active material for a lithium ion secondary battery, characterized in that the silicon atom content is 100 to 1000 ppm and the fluorine atom content is 300 to 900 ppm. A metal composite oxide is provided.

  In the present invention (2), a lithium compound, a transition metal compound, a fluorine compound and a silicon compound are mixed to obtain a raw material mixture, and then the raw material mixture is fired to obtain a lithium transition metal composite oxide. The present invention provides a method for producing a lithium transition metal composite oxide.

  In addition, the present invention (3) provides a positive electrode active material for a lithium ion secondary battery comprising the lithium transition metal composite oxide for a positive electrode active material of the lithium ion secondary battery of the present invention (1). To do.

  Moreover, this invention (4) provides the lithium ion secondary battery characterized by being obtained using the positive electrode active material for lithium ion secondary batteries of the said invention (3).

  ADVANTAGE OF THE INVENTION According to this invention, the lithium transition metal complex oxide for lithium ion secondary battery positive electrode active materials which can provide the performance which was excellent in the lithium ion secondary battery, especially can make cycling characteristics high, and its A manufacturing method, and a positive electrode active material for a lithium ion secondary battery and a lithium ion secondary battery obtained by using the method can be provided. In addition, according to the present invention, it is possible to provide a method for producing a lithium transition metal composite oxide, in which the fired powder is hardly fixed to the fired container and is industrially advantageous.

  The lithium transition metal composite oxide for a positive electrode active material of a lithium ion secondary battery of the present invention (hereinafter also referred to as a lithium transition metal composite oxide of the present invention) is lithium used as a positive electrode active material of a lithium ion secondary battery. It is a transition metal complex oxide.

  The positive electrode active material of a lithium ion secondary battery includes a main active material that repeatedly charges and discharges electrons and a secondary active material that prevents performance deterioration of the main active material by supplying electrons to the main active material. The lithium transition metal composite oxide of the present invention may be used as a main active material or as a secondary active material depending on the composition.

  The lithium transition metal composite oxide of the present invention is a lithium transition metal composite oxide containing a fluorine atom and a silicon atom. Content of the silicon atom in the lithium transition metal complex oxide of this invention is 100-1000 ppm, Preferably it is 200-800 ppm. Moreover, content of the fluorine atom in the lithium transition metal complex oxide of this invention is 300-900 ppm, Preferably it is 400-800 ppm. When both the content of silicon atoms and the content of fluorine atoms in the lithium transition metal composite oxide of the present invention are within the above range, the effect of stabilizing the crystal structure due to the synergistic effect of silicon and fluorine Therefore, the cycle characteristics of the lithium ion secondary battery are improved. On the other hand, if the content of silicon atoms in the lithium transition metal composite oxide is less than the above range, the effect of improving the cycle characteristics cannot be sufficiently obtained, and if it exceeds the above range, the safety of the battery is reduced due to gas generation or the like. And the gelation of the paint during electrode application becomes significant. Moreover, if the content of fluorine atoms in the lithium transition metal composite oxide is less than the above range, the effect of suppressing the generation of gas derived from the inclusion of silicon atoms and the effect of suppressing the gelation of the paint cannot be sufficiently obtained. If the above range is exceeded, the battery performance is significantly reduced due to the decrease in conductivity.

In the lithium transition metal composite oxide of the present invention, the lithium transition metal composite oxide containing a fluorine atom and a silicon atom is
(I) lithium;
One or more transition metal elements selected from cobalt, nickel, manganese, iron, vanadium, chromium, zirconium, copper and titanium;
A composite oxide consisting of
(Ii) lithium;
One or more transition metal elements selected from cobalt, nickel, manganese, iron, vanadium, chromium, zirconium, copper and titanium;
Elements other than these transition metal elements,
A composite oxide consisting of
For example, LiCoO ₂ , Li _r1 Ni _(1-p1-q1) Co _p1 Mn _q1 O ₂ (wherein r1 is 0.4 <r1 <1.3, preferably 0.8 ≦ r1 ≦ 1.2, p1 is 0 <p1 <1.0, preferably 0.05 ≦ p1 ≦ 0.5, and q1 is 0 <q1 <1.0, preferably 0.05 ≦ q1 ≦ 0.5), LiFePO ₄ , Li _r2 Ni _(1-p2-q2) Co _p2 Al _q2 O ₂ (wherein r2 is 0.4 <r2 <1.3, preferably 0 0.8 ≦ r2 ≦ 1.2, p2 is 0 <p2 <1.0, preferably 0.05 ≦ p2 ≦ 0.5, and q2 is 0 <q2 <0.2, preferably is _{0.01 ≦ q2 ≦ 0.1.),} LiNi p3 Mn (1-p3) O 4 ( wherein, p3 1.3 a p3 ≦ 1.7, preferably from 1.4 ≦ p3 ≦ 1.6.), LiMn 2 O 4 and the like. Among these, LiCoO ₂ is preferable in that a lithium ion secondary battery with high cycle characteristics can be obtained because the effect of stabilizing the crystal structure due to the synergistic effect of fluorine atoms and silicon atoms is increased.

  In addition, the lithium transition metal composite oxide of the present invention contains a trace amount (less than 1% by weight) of different elements such as Mg and Al in order to improve the safety and charge / discharge characteristics of the lithium ion secondary battery. Can do.

  The average particle size of the lithium transition metal composite oxide of the present invention is preferably 0.5 to 30.0 μm, particularly preferably 5 to 25 μm. It is preferable that the average particle diameter of the lithium transition metal composite oxide of the present invention is in the above-mentioned range because the safety of the lithium ion secondary battery can be increased and the filling property can be enhanced.

The BET specific surface area of the lithium transition metal composite oxide of the present invention is preferably 0.05 to 2.0 m ² / g, particularly preferably 0.10 to 1.5 m ² / g, and further preferably 0.15 to 1. 0.0 m ² / g. The BET specific surface area of the lithium transition metal composite oxide of the present invention is preferably in the above range from the viewpoint of increasing the safety of the lithium ion secondary battery.

The residual alkali amount of the lithium transition metal composite oxide of the present invention is preferably 0.005 to 0.15%, particularly preferably 0.01 to 0.1%. In the present invention, the residual alkali amount is the amount of a monovalent or divalent basic component contained in the lithium transition metal composite oxide, and the monovalent and divalent alkali components determined by acid-base titration. Is a value converted to Li ₂ CO ₃ amount. When the residual alkali amount of the lithium transition metal composite oxide of the present invention is within the above range, battery characteristics such as discharge capacity are improved, and coating failure due to gelation of the paint during electrode coating, It is difficult to generate gas. On the other hand, if the residual alkali amount of the lithium transition metal composite oxide is less than the above range, the battery characteristics such as the discharge capacity tend to be low, and if it exceeds the above range, the cause of the coating failure due to the gelation of the paint at the time of electrode application And gas generation inside the battery is likely to occur.

  The method for producing a lithium transition metal composite oxide of the present invention (hereinafter also referred to as the production method of the present invention) comprises mixing a lithium compound, a transition metal compound, a fluorine compound and a silicon compound to obtain a raw material mixture, The method for producing a lithium transition metal composite oxide by firing the raw material mixture to obtain a lithium transition metal composite oxide.

  In the production method of the present invention, first, a lithium compound, a transition metal compound, a fluorine compound, and a silicon compound are mixed to obtain a raw material mixture.

The lithium compound according to the production method of the present invention is not particularly limited as long as it is a compound having lithium as a main constituent element, and examples thereof include lithium salts, lithium oxides, organic lithium salts, and the like. Examples include lithium carbonate (Li ₂ CO ₃ ), lithium hydroxide (LiOH), lithium nitrate (LiNO ₃ ), and the like. Examples of the lithium oxide include lithium oxide (Li ₂ O). Examples thereof include lithium alkoxides such as lithium acetate (CH ₃ COOLi) and lithium ethoxide (C ₂ H ₅ OLi). Of these, lithium carbonate is preferred because it is industrially inexpensive. The lithium compound according to the production method of the present invention may be a combination of two or more lithium compounds. The physical properties of the lithium compound according to the production method of the present invention are not particularly limited, but it is preferable that the particle size is small in that the distribution of lithium in the raw material mixture can be made more uniform, and the reactivity is increased. The average particle size of the lithium compound is particularly preferably 0.1 to 200 μm, and more preferably 2 to 50 μm.

  Examples of the transition metal compound according to the production method of the present invention include oxides and transition metal salts containing at least one transition element selected from cobalt, nickel, manganese, iron, vanadium, chromium, zirconium, copper and titanium. Examples of transition metal salts include hydroxides, oxyhydroxides, nitrates, carbonates, and oxalates. The transition metal compound according to the production method of the present invention may be a composite compound containing two or more transition elements selected from cobalt, nickel, manganese, iron, vanadium, chromium, zirconium, copper and titanium, Examples of the composite compound include composite oxide, composite hydroxide, composite oxyhydroxide, composite nitrate, composite carbonate, composite oxalate, etc. Among these, composite hydroxide, composite oxyhydroxide, Complex carbonates or complex oxides are preferred. Further, the transition metal compound according to the production method of the present invention may be a combination of two or more transition metal compounds. The composite hydroxide is prepared, for example, by a coprecipitation method. Specifically, the composite hydroxide can be coprecipitated by mixing an aqueous solution containing two or more transition elements according to the production method of the present invention, an aqueous solution of a complexing agent, and an aqueous alkali solution. (See JP-A-10-81521, JP-A-10-81520, JP-A-10-29820, JP-2002-201028, etc.). Moreover, when using a composite oxyhydroxide, after obtaining the composite hydroxide precipitate according to the above-described coprecipitation operation, air may be blown into the reaction solution to oxidize the composite hydroxide. Moreover, when using complex oxide, after obtaining precipitation of complex hydroxide according to the above-mentioned coprecipitation operation, this can be heat-processed at 200-500 degreeC, for example, and complex oxide can be obtained. . In the case of using a composite carbonate, an aqueous solution containing two or more transition elements and an aqueous solution of a complexing agent are prepared in the same manner as in the coprecipitation operation described above, and the alkaline aqueous solution is used as an alkali carbonate or hydrogen carbonate aqueous solution By mixing this, a composite carbonate can be obtained. The physical properties of the transition metal compound according to the production method of the present invention are not particularly limited, but it is preferable that the particle size is small and the reactivity is increased in that the distribution of the transition metal in the raw material mixture can be made more uniform. The average particle size of the transition metal compound is particularly preferably 0.1 to 50 μm, and more preferably 2 to 25 μm.

The fluorine compound according to the production method of the present invention is not particularly limited as long as it is a compound having fluorine as a main constituent element, and examples thereof include fluoride salts. Examples of fluoride salts include LiF, CaF ₂ , MgF ₂ , CoF ₂ , AlF _{3 and the} like can be mentioned, and among these, LiF or MgF ₂ is preferable in terms of high reactivity with the transition metal complex oxide. Moreover, the combination of 2 or more types of fluorine compounds may be sufficient as the fluorine compound which concerns on the manufacturing method of this invention. The physical properties of the fluorine compound according to the production method of the present invention are not particularly limited, but it is preferable that the particle size is small in that the distribution of fluorine in the raw material mixture can be made more uniform, and that the reactivity is increased. The average particle size of is preferably 0.1 to 100 μm, and more preferably 5 to 50 μm.

The silicon compound according to the production method of the present invention is not particularly limited as long as it is a compound having silicon as a main constituent element. For example, SiO _x such as SiO ₂ (wherein x is 1 ≦ x ≦ 2) Yes, preferably 1.5 ≦ x ≦ 2.) M _y SiO _z such as Li ₂ SiO ₃ , MgSiO ₃ , CoSiO ₃ , NiSiO ₃ , MnSiO ₃ (where M is One or more elements selected from Li, H, Co, Ni, Mn, Ti, Zr, Mg, and Al, y is 0 <y ≦ 4, preferably 2 ≦ y ≦ 4, and z is 2 <z ≦ 4, preferably 3 ≦ z ≦ 4)). Of these, SiO ₂ is preferable because it is easy to handle and easily available. Moreover, the combination of 2 or more types of silicon compounds may be sufficient as the silicon compound which concerns on the manufacturing method of this invention. The physical properties of the silicon compound according to the production method of the present invention are not particularly limited, but it is preferable that the particle size is small in that the distribution of silicon in the raw material mixture can be made more uniform, and the reactivity is increased. The average particle size of the silicon compound is particularly preferably 0.1 μm to 200 μm, and more preferably 5 to 50 μm.

  In addition, the lithium compound, transition metal compound, fluorine compound and silicon compound according to the production method of the present invention are not limited in production history, but in order to produce a high-purity lithium transition metal composite oxide as much as possible. Those having a low impurity content are preferred.

  In the production method of the present invention, the mixing amount of the lithium compound in the raw material mixture is the ratio of the number of moles of lithium atoms (Li) in the lithium compound to the total number of moles (T) of all transition metal atoms in the transition metal compound ( The molar ratio Li / T) is preferably such an amount that 0.90 to 1.20, and the molar ratio Li / T is particularly preferably 0.98 to 1.15, more preferably 1.00 to 1. .10. It is preferable that the molar ratio Li / T is within the above range because the discharge capacity is increased or the discharge capacity is increased and the discharge capacity is hardly lowered. On the other hand, if the molar ratio Li / T is less than the above range, the discharge capacity tends to be low, and if it exceeds the above range, the cycle characteristics tend to be low.

  In the production method of the present invention, the mixing amount of the fluorine compound in the raw material mixture is the ratio of the number of moles of fluorine atoms (F) in the fluorine compound to the total number of moles (T) of all transition metal atoms in the transition metal compound ( The molar ratio F / T) is preferably in an amount of 0.0001 to 0.02, and the molar ratio F / T is particularly preferably 0.001 to 0.01. When the molar ratio F / T is within the above range, cycle characteristics are improved, which is preferable.

  In the production method of the present invention, the mixing amount of the silicon compound in the raw material mixture is the ratio of the number of moles of fluorine atoms (F) in the fluorine compound to the total number of moles of silicon atoms (Si) in the raw material mixture (molar ratio F / Si) is an amount to be 0.5 to 20, and the molar ratio F / Si is preferably 1 to 10. When the molar ratio F / Si is within the above range, the cycle characteristics are improved, and the fired powder does not adhere to the fired container. In addition, the silicon atom may be contained also in the transition metal compound, and when the transition metal compound also contains the silicon atom, the total number of moles of silicon atoms (Si) in the raw material mixture is the silicon compound. It is the sum total of the number of moles of silicon atoms in the number of moles of silicon atoms in the transition metal compound.

  The method for mixing the lithium compound, the transition metal compound, the fluorine compound and the silicon compound is not particularly limited, and any method of dry mixing or wet mixing may be used. Of these, dry mixing is preferred in that the production process is simple. In the case of dry mixing, it is preferable to use a blender or the like that can uniformly mix the raw materials.

  In the production method of the present invention, the raw material mixture is then fired to obtain a lithium transition metal composite oxide. When firing the raw material mixture, the raw material mixture is filled in a firing container and fired. The material of the firing container is not particularly limited as long as it does not cause cracking of the firing container or decrease in strength in the heating or cooling process during firing. For example, mullite; cordierite; mullite or cordierite; Examples include those coated with spinel, magnesia, alumina, silicon carbide or zirconia. Among these, mullite or cordierite is preferable in terms of high mechanical strength and durability against thermal shock. And the manufacturing method of this invention exhibits the sticking prevention effect of the especially outstanding baked powder with respect to the baking container made from a mullite or a cordierite.

  In the production method of the present invention, the firing furnace in which the firing container is installed is not particularly limited as long as the raw material mixture can be heated uniformly, and may be a batch-type firing furnace or a continuous firing furnace. Therefore, a continuous firing furnace is preferable. Examples of the continuous firing furnace include a pusher-type heating firing furnace and a roller hearth kiln.

  In the production method of the present invention, the firing conditions for firing the raw material mixture are not particularly limited, and are appropriately selected depending on the type of lithium compound, transition metal compound, fluorine compound, and silicon compound. For example, when a compound that generates moisture in the firing process such as hydroxide, oxyhydroxide or hydrated salt is mixed in the raw material mixture, it is preferable to carry out by multi-stage firing. In order to make it disappear, after baking for 1 to 5 hours (preliminary baking) in the range of about 200 to 400 ° C., it is preferable to further carry out baking (main baking) at 600 to 1150 ° C. for 1 to 30 hours. In addition, for the purpose of reducing oxygen defects in the lithium transition metal composite oxide, firing (post-baking) can be further performed at 500 to 700 ° C. for 1 to 10 hours after the main firing.

  In the production method of the present invention, the firing atmosphere when firing the raw material mixture is an oxidizing atmosphere, and the atmosphere is preferable because the atmosphere can be easily controlled. In addition, when baking a raw material mixture by multistage baking, what is necessary is just an oxidizing atmosphere at the time of main baking, and the atmosphere at the time of temporary baking is not restrict | limited in particular.

  In the production method of the present invention, the raw material mixture is fired and then appropriately cooled, and pulverized and classified as necessary to obtain a lithium transition metal composite oxide. The pulverization performed as necessary is performed when the lithium transition metal composite oxide obtained by firing is in the form of a crumbly bonded block.

The lithium transition metal composite oxide particles themselves obtained by the production method of the present invention have an average particle diameter of preferably 0.5 to 30.0 μm, particularly preferably 5 to 25 μm, and a BET specific surface area of preferably Is 0.05 to 2.0 m ² / g, particularly preferably 0.10 to 1.5 m ² / g, and still more preferably 0.15 to 1.0 m ² / g.

The production method of the present invention is characterized in that a silicon compound is further mixed in a specific ratio to a raw material mixture composed of a lithium compound, a transition metal compound and a fluorine compound. And by firing a raw material mixture of a lithium compound, a transition metal compound, a fluorine compound and a silicon compound in which a silicon compound is mixed at a specific ratio,
(I) At the time of firing, it is possible to prevent the fired powder from sticking to the fired container, and therefore, the lithium transition metal composite oxide can be produced industrially advantageously,
(Ii) A lithium transition metal composite oxide that provides a lithium ion secondary battery with high cycle characteristics can be obtained.

  Sticking means that the baked powder reacts with the reaction vessel so that the baked powder is firmly attached to the reaction vessel. Even if the reaction vessel is turned upside down, the block-like baked powder does not fall under its own weight. In a state where the calcined powder is attached to the reaction vessel, or even when falling due to its own weight, the calcined powder is peeled off in a state where a part of the calcined container is peeled off and a peeled piece of the calcined container is attached to the calcined powder Point to. Further, the fixing includes not only the case where the block-like fired powder is firmly attached to all the contact surfaces with the firing container but also the case where the block-like fired powders are firmly attached to a part of the contact surface.

  It is not clear why mixing the silicon compound with the raw material mixture prevents the fired powder from sticking to the fired container, but since the fluorine component and silicon component in the raw material mixture react preferentially, This is probably because the reaction between the fluorine component in the raw material mixture and the silicon component in the mullite baking container is suppressed, and the reaction between the baking powder and the baking container is suppressed.

  The positive electrode active material for a lithium ion secondary battery of the present invention contains the lithium transition metal composite oxide for a positive electrode active material of the lithium ion secondary battery of the present invention.

  More specifically, the positive electrode active material for a lithium ion secondary battery of the present invention is as follows. (A) When the positive electrode active material for a lithium ion secondary battery does not contain a secondary active material, the positive electrode active material for a lithium ion secondary battery of the present invention is composed of all or part of the main active material lithium of the present invention. It is a lithium transition metal composite oxide for an ion secondary battery positive electrode active material. (B) When the positive electrode active material for a lithium ion secondary battery is composed of a main active material and a secondary active material, the positive electrode active material for a lithium ion secondary battery of the present invention is (i) the entire main active material. Or a part is a lithium transition metal composite oxide for a lithium ion secondary battery positive electrode active material of the present invention, or (ii) all or a part of the secondary active material is a lithium ion secondary battery positive electrode active material of the present invention. Lithium transition metal composite oxide for materials, or (iii) all or part of the main active material and all or part of the secondary active material are lithium transition metals for the positive electrode active material of the lithium ion secondary battery of the present invention It is a complex oxide.

  The lithium ion secondary battery of the present invention is a lithium ion secondary battery obtained by using the positive electrode active material for a lithium ion secondary battery of the present invention, and includes a positive electrode, a negative electrode, a separator, and a lithium salt. Consists of.

  The positive electrode according to the lithium ion secondary battery of the present invention is formed, for example, by applying and drying a positive electrode mixture on a positive electrode current collector, and the positive electrode mixture is the lithium ion secondary battery of the present invention. A positive electrode active material, a conductive agent, a binder, and a filler added if necessary. In the lithium ion secondary battery of the present invention, the lithium transition metal composite oxide of the present invention is uniformly applied to the positive electrode. For this reason, the lithium ion secondary battery of the present invention has particularly high load characteristics such as initial discharge capacity and initial discharge voltage, and cycle characteristics.

  The content of the positive electrode active material in the positive electrode mixture is 70 to 98% by mass, preferably 90 to 95% by mass.

  The conductive agent is not particularly limited as long as it is an electron conductive material that does not cause a chemical change in the constructed battery. For example, graphite such as natural graphite and artificial graphite, carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, carbon black such as thermal black, conductive fibers such as carbon fiber and metal fiber, Examples include metal powders such as carbon fluoride, aluminum and nickel powder, conductive whiskers such as zinc oxide and potassium titanate, conductive metal oxides such as titanium oxide, and conductive materials such as polyphenylene derivatives. Examples of graphite include scaly graphite, scaly graphite, and earthy graphite. The conductive agent may be a single type or a combination of two or more types. Content of the electrically conductive agent in a positive mix is 1-50 mass%, Preferably it is 2-30 weight%.

Examples of the binder include starch, polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, regenerated cellulose, diacetylcellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer ( EPDM), sulfonated EPDM, styrene butadiene rubber, fluoro rubber, tetrafluoroethylene-hexafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, fluorinated Vinylidene-hexafluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene Oroethylene copolymer, polychlorotrifluoroethylene, vinylidene fluoride-pentafluoropropylene copolymer, propylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetra Fluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, ethylene-acrylic acid copolymer or its (Na ⁺ ) ionic crosslinked product, ethylene-methacrylic acid copolymer or its (Na ⁺ ) Ionic cross-linked product, ethylene-methyl acrylate copolymer or its (Na ⁺ ) ionic cross-linked product, ethylene-methyl methacrylate copolymer or its (Na ⁺ ) ionic cross-linked product, polysaccharides such as polyethylene oxide, heat Plasticity Resin, polymer having rubber elasticity, and the like, and these may be used alone or in combination of two or more. In addition, when using the compound containing a functional group which reacts with lithium like a polysaccharide, it is preferable to add the compound like an isocyanate group and to deactivate the functional group, for example. The content of the binder in the positive electrode mixture is 1 to 50% by mass, preferably 5 to 15% by mass.

  The filler suppresses the volume expansion of the positive electrode in the positive electrode mixture, and is added as necessary. Any filler may be used as long as it is a fibrous material that does not cause a chemical change in the constructed battery. For example, an olefin polymer such as polypropylene or polyethylene, or a fiber such as glass or carbon is used. Although content of the filler in a positive mix is not specifically limited, 0-30 mass% is preferable.

  The positive electrode current collector is not particularly limited as long as it is an electronic conductor that does not cause a chemical change in the constituted battery. For example, the positive electrode current collector is formed on the surface of stainless steel, nickel, aluminum, titanium, calcined carbon, aluminum, or stainless steel. Examples include carbon, nickel, titanium, and silver surface-treated. In addition, these materials may be oxidized products whose surfaces are oxidized, or may be surface-treated products having irregularities on the current collector surface by surface treatment. Examples of the shape of the current collector include foils, films, sheets, nets, punched ones, lath bodies, porous bodies, foams, fiber groups, and nonwoven fabric molded bodies. The thickness of the current collector is not particularly limited, but is preferably 1 to 500 μm.

  The negative electrode is formed by applying and drying a negative electrode material on the negative electrode current collector. The negative electrode current collector is not particularly limited as long as it is an electronic conductor that does not cause a chemical change in a configured battery. For example, stainless steel, nickel, copper, titanium, aluminum, calcined carbon, copper or stainless steel Examples of the steel surface include carbon, nickel, titanium, silver surface-treated, and an aluminum-cadmium alloy. Further, the surface of these materials may be used after being oxidized, or the surface of the current collector may be used with surface roughness by surface treatment. Examples of the current collector include foils, films, sheets, nets, punched ones, lath bodies, porous bodies, foam bodies, fiber groups, nonwoven fabric molded bodies, and the like. The thickness of the current collector is not particularly limited, but is preferably 1 to 500 μm.

The negative electrode material is not particularly limited, and examples thereof include carbonaceous materials, metal composite oxides, lithium metals, lithium alloys, silicon-based alloys, tin-based alloys, metal oxides, conductive polymers, and chalcogen compounds. And Li—Co—Ni-based materials. Examples of the carbonaceous material related to the negative electrode material include non-graphitizable carbon materials and graphite-based carbon materials. Examples of the metal composite oxide according to the negative electrode material include Sn _a (A ¹ ) _(1-a) (A ² ) _b O _c (wherein A ¹ is one selected from Mn, Fe, Pb, and Ge) A ² represents one or more elements selected from Al, B, P, Si, Group 1, Group 2, Group 3, and halogen element of the periodic table, and a represents 0 <a ≦ 1, b is 1 ≦ b ≦ 3, c is 1 ≦ c ≦ 8); Li _d Fe ₂ O ₃ (where d is 0 ≦ d ≦ 1); Li _e WO ₂ ( In the formula, e is 0 ≦ e ≦ 1, and the like. Examples of the metal oxide according to the negative electrode material include GeO, GeO ₂ , SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , _{Bi 2 O 3, Bi 2 O} 4, Bi 2 O 5 and the like. Examples of the conductive polymer according to the negative electrode material include polyacetylene and poly-p-phenylene.

  As the separator, an insulating thin film having a large ion permeability and a predetermined mechanical strength is used. From the standpoint of organic solvent resistance and hydrophobicity, an olefin polymer such as polypropylene, a glass fiber, or a sheet or nonwoven fabric made of polyethylene is used. The pore diameter of the separator may be in a range generally useful for batteries, and is, for example, 0.01 to 10 μm. The thickness of the separator may be in a range for a general battery, for example, 5 to 300 μm. In addition, when solid electrolytes, such as a polymer, are used as the electrolyte described later, the solid electrolyte may also serve as a separator.

  The non-aqueous electrolyte containing a lithium salt is composed of a non-aqueous electrolyte and a lithium salt. As the non-aqueous electrolyte, a non-aqueous electrolyte, an organic solid electrolyte, or an inorganic solid electrolyte is used. Examples of the non-aqueous electrolyte include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, and 2-methyl. Tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 3-methyl -2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, diethyl ether, 1,3- Ropansaruton, methyl propionate, and a solvent obtained by mixing one or more aprotic organic solvents such as ethyl propionate.

  Examples of the organic solid electrolyte include a polyethylene derivative, a polyethylene oxide derivative or a polymer containing the same, a polypropylene oxide derivative or a polymer containing the same, a phosphate ester polymer, polyphosphazene, polyaziridine, polyethylene sulfide, polyvinyl alcohol, polyvinylidene fluoride, Examples thereof include a polymer containing an ionic dissociation group such as polyhexafluoropropylene, and a mixture of a polymer containing an ionic dissociation group and the above non-aqueous electrolyte.

As the inorganic solid electrolyte, a nitride, halide, oxyacid salt, sulfide, or the like of Li is used. For example, Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N—LiI—LiOH, LiSiO ₄ , LiSiO _{4 -LiI-LiOH, Li 2 SiS} 3, Li 4 SiO 4, Li 4 SiO 4 -LiI-LiOH, P 2 S 5, Li 2 S or _{Li 2 S-P 2 S 5} , Li 2 S-SiS 2, _{Li 2 S-GeS 2, Li} 2 S-Ga 2 S 3, Li 2 S-B 2 S 3, Li 2 S-P 2 S 5 -X, Li 2 S-SiS 2 -X, Li 2 S-GeS _{2 -X, Li 2 S-Ga} 2 S 3 -X, Li 2 S-B 2 S 3 -X, ( wherein, X is _LiI, B 2 _{S 3,} or at least one selected from _Al 2 _{S 3} And the like).

Further, when the inorganic solid electrolyte is amorphous (glass), lithium phosphate (Li ₃ PO ₄ ), lithium oxide (Li ₂ O), lithium sulfate (Li ₂ SO ₄ ), phosphorus oxide (P ₂ O ₅₎ ), Compounds containing oxygen such as lithium borate (Li ₃ BO ₃ ); Li ₃ PO _(4-f) N _{(2f / 3)} (wherein f is 0 <f <4), Li ₄ SiO _{(4- g)} N _{(2 g / 3)} (where g is 0 <g <4), Li ₄ GeO _(4-h) N _{(2h / 3)} (where h is 0 <h <4), Li ₃ BO _(3-i) N _{(2i / 3)} (wherein i is 0 <i <3) and the like can contain a nitrogen-containing compound in the inorganic solid electrolyte. By the addition of the compound containing oxygen or the compound containing nitrogen, the lithium ion (Li ⁺ ) hops the unshared electron pair of the oxygen or nitrogen atom, thereby improving the conductivity of the lithium ion.

As the lithium salt related to the non-aqueous electrolyte containing a lithium salt, those dissolved in the non-aqueous electrolyte are used. For example, LiCl, LiBr, LiI, LiClO ₄ , LiBF ₄ , LiB ₁₀ Cl ₁₀ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , LiSbF ₆ , LiAlCl ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, (C ₂ O ₄ ) ₂ BLi, chloroborane Examples thereof include a salt obtained by mixing one or more of lithium, lower aliphatic lithium carboxylate, lithium tetraphenylborate, imides and the like.

  In addition, the nonaqueous electrolyte may contain the following compounds for the purpose of improving discharge, charge characteristics, and flame retardancy. For example, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivative, sulfur, quinoneimine dye, N-substituted oxazolidinone and N, N-substituted imidazolidine, ethylene glycol dialkyl ether , Ammonium salt, polyethylene glycol, pyrrole, 2-methoxyethanol, aluminum trichloride, conductive polymer electrode active material monomer, triethylenephosphonamide, trialkylphosphine, morpholine, aryl compounds with carbonyl group, hexamethylphosphine Examples include hollic triamide and 4-alkylmorpholine, bicyclic tertiary amines, oils, phosphonium salts and tertiary sulfonium salts, phosphazenes, and carbonates. That. Further, the non-aqueous electrolyte can contain a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride in order to make the electrolyte nonflammable. Further, in order to give the non-aqueous electrolyte suitable for high-temperature storage, carbon dioxide can be contained in the electrolyte.

  The lithium ion secondary battery of the present invention has high battery performance, particularly cycle characteristics, and the battery may have any shape such as a button, a sheet, a cylinder, a corner, or a coin type.

  The use of the lithium ion secondary battery of the present invention is not particularly limited. For example, a laptop computer, a laptop computer, a pocket word processor, a mobile phone, a cordless cordless handset, a portable CD player, a radio, an LCD TV, a backup power source, and an electric shaver. And electronic devices such as memory cards and video movies, and consumer electronic devices such as automobiles, electric vehicles, and game machines.

  EXAMPLES Next, although an Example is given and this invention is demonstrated more concretely, this is only an illustration and does not restrict | limit this invention.

(Measurement of average particle size)
The average particle size was measured using a microtrack (manufactured by Nikkiso Co., Ltd., HRA (X100)).

(Measurement of silicon atom content)
Lithium cobaltate was dissolved by heating with perchloric acid, and the silicon content in the solution was measured with an inductively coupled plasma (ICP) measuring device (Liberty II, manufactured by Varian).

(Measurement of fluorine atom content)
100 g of ultrapure water was added to 0.5 g of lithium cobaltate, and the mixture was sufficiently stirred at 25 ° C. to elute F atoms from lithium cobaltate into water, and the amount of F atoms in the solution was quantified by ion chromatography.

(Residual alkali amount measurement)
10 g of lithium cobaltate and 50 g of ultrapure water were weighed into a 100 mL beaker, stirred for 5 minutes, and then the supernatant was filtered off (filtrate A). After removing the supernatant, 50 g of ultrapure water was further added and stirred for 5 minutes, and then the supernatant was filtered off (filtrate B). 60 g was weighed out from the mixed solution obtained by mixing the filtrate A and the filtrate B, and titrated with a 0.1N aqueous HCl solution. The content of the alkali component was determined from the amount of aqueous HCl solution required for titration, and the value converted to the amount of Li ₂ CO ₃ was defined as the residual alkali amount.

Example 1
Commercially available lithium carbonate (manufactured by SQM, average particle diameter 7 μm), commercially available cobalt oxide (Co ₃ O ₄ ; manufactured by OMG, average particle diameter 5 μm), commercially available magnesium fluoride (MgF ₂ ; manufactured by Stella Chemifa, average) A particle size of 6 μm) and commercially available silicon oxide (SiO ₂ ; manufactured by Junsei Chemical Co., Ltd., average particle size of 17 μm) were weighed as shown in Table 1, and mixed well in a mortar to prepare a uniform raw material mixture. Next, the prepared raw material mixture was filled in a round mortar made of mullite (manufactured by Toshiba Ceramics Co., Ltd., R2013, inner diameter 13 cm), placed in an electric heating furnace, heated in an air atmosphere, and at a temperature of 1020 ° C. for 5 hours. It was held and fired. After cooling the obtained block-like fired product and the mortar in the air, by turning the mortar upside down, it was confirmed whether the baked powder and the firing container were firmly fixed. It was confirmed that it dropped without peeling and did not adhere. The obtained block-like fired product was pulverized and classified to obtain lithium cobaltate powder. As the powder characteristics of the obtained lithium cobaltate, the average particle size, BET specific surface area, silicon content, fluorine content and residual alkali amount were measured. The measurement results are shown in Table 2. The same lithium cobalt oxide was used for the battery performance test. Furthermore, the lithium cobaltate firing process under the above conditions was repeated 20 times using the same mullite mortar, but no sticking occurred.

(Examples 2 to 4)
A uniform raw material mixture was prepared in the same manner as in Example 1 except that the amount of the raw material mixture was changed to the amount shown in Table 1. Next, the prepared raw material mixture was filled in a round mortar made of mullite (manufactured by Toshiba Ceramics Co., Ltd., R2013, inner diameter 13 cm), placed in an electric heating furnace, heated in an air atmosphere, and heated at a temperature of 1020 ° C. It was held for a time and fired. After cooling the obtained block-like fired product and the mortar in the air, the mortar was turned upside down to confirm whether the fired powder and the firing container were firmly fixed. Dropped without any peeling of the bowl, and it was confirmed that it did not stick. The obtained block-like fired product was pulverized and classified to obtain lithium cobaltate powder. As the powder characteristics of the obtained lithium cobaltate, the average particle size, BET specific surface area, silicon content, fluorine content and residual alkali amount were measured. The measurement results are shown in Table 2. The same lithium cobalt oxide was used for the battery performance test. Further, the baking treatment was repeated 20 times in the same manner as in Example 1 using the same mullite mortar, but none of them fixed.

(Comparative Example 1)
A uniform raw material mixture was prepared in the same manner as in Example 1 except that the amount of the raw material compound was changed to the amount shown in Table 1. Next, the prepared raw material mixture was filled in a round mortar made of mullite (manufactured by Toshiba Ceramics Co., Ltd., R2013, inner diameter 13 cm), placed in an electric heating furnace, heated in an air atmosphere, and heated at a temperature of 1020 ° C. It was held for a time and fired. After cooling the obtained block-shaped fired product and mortar in the air, the mortar was turned upside down to confirm whether the fired powder and the firing container were fixed. It was confirmed that the fired powder was fixed to the mortar. The block-like fired product was collected so that the mortar component was not mixed, and further pulverized and classified to obtain lithium cobaltate powder. The average particle diameter, BET specific surface area, silicon content, fluorine content and residual alkali content of the obtained lithium cobalt oxide powder were measured. The measurement results are shown in Table 2.

(Comparative Example 2)
A uniform raw material mixture was prepared in the same manner as in Example 1 except that the amount of the raw material mixture was changed to the amount shown in Table 1. Next, the prepared raw material mixture was filled in a round mortar made of mullite (manufactured by Toshiba Ceramics Co., Ltd., R2013, inner diameter 13 cm), placed in an electric heating furnace, heated in an air atmosphere, and heated at a temperature of 1020 ° C. It was held for a time and fired. After cooling the obtained block-like fired product and the mortar in the air, by turning the mortar upside down, it was confirmed whether the baked powder and the firing container were firmly fixed. It was confirmed that it dropped without peeling and did not adhere. The obtained block-like fired product was pulverized and classified to obtain lithium cobaltate powder. The average particle diameter, BET specific surface area, silicon content, fluorine content and residual alkali content of the obtained lithium cobalt oxide powder were measured. The measurement results are shown in Table 2.

(Comparative Example 3)
A uniform raw material mixture was prepared in the same manner as in Example 1 except that the amount of the raw material mixture was changed to the amount shown in Table 1. Next, the prepared raw material mixture was filled in a round mortar made of mullite (manufactured by Toshiba Ceramics Co., Ltd., R2013, inner diameter 13 cm), placed in an electric heating furnace, heated in an air atmosphere, and heated at a temperature of 1020 ° C. It was held for a time and fired. After cooling the obtained block-like fired product and the mortar in the air, by turning the mortar upside down, it was confirmed whether the baked powder and the firing container were firmly fixed. It was confirmed that it dropped without peeling and did not adhere. The obtained block-like fired product was pulverized and classified to obtain lithium cobaltate powder. The average particle diameter, BET specific surface area, silicon content, fluorine content and residual alkali content of the obtained lithium cobalt oxide powder were measured. The measurement results are shown in Table 2.

(Comparative Example 4)
A uniform raw material mixture was prepared in the same manner as in Example 1 except that the amount of the raw material mixture was changed to the amount shown in Table 1. Next, the prepared raw material mixture was filled in a round mortar made of mullite (manufactured by Toshiba Ceramics Co., Ltd., R2013, inner diameter 13 cm), placed in an electric heating furnace, heated in an air atmosphere, and heated at a temperature of 1020 ° C. It was held for a time and fired. After cooling the obtained block-shaped fired product and mortar in the air, the mortar was turned upside down to confirm whether the fired powder and the firing container were fixed. It was confirmed that the fired powder was fixed to the mortar. The block-like fired product was collected so that the mortar component was not mixed, and further pulverized and classified to obtain lithium cobaltate powder. The average particle diameter, BET specific surface area, silicon content, fluorine content and residual alkali content of the obtained lithium cobalt oxide powder were measured. The measurement results are shown in Table 2.

(Comparative Example 5)
A uniform raw material mixture was prepared in the same manner as in Example 1 except that the amount of the raw material mixture was changed to the amount shown in Table 1. Next, the prepared raw material mixture was filled in a round mortar made of mullite (manufactured by Toshiba Ceramics Co., Ltd., R2013, inner diameter 13 cm), placed in an electric heating furnace, heated in an air atmosphere, and heated at a temperature of 1020 ° C. It was held for a time and fired. After cooling the obtained block-shaped fired product and mortar in the air, the mortar was turned upside down to confirm whether the fired powder and the firing container were fixed. It was confirmed that the fired powder was fixed to the mortar. The block-like fired product was collected so that the mortar component was not mixed, and further pulverized and classified to obtain lithium cobaltate powder. The average particle diameter, BET specific surface area, silicon content, fluorine content and residual alkali content of the obtained lithium cobalt oxide powder were measured. The measurement results are shown in Table 2.

(Comparative Example 6)
A uniform raw material mixture was prepared in the same manner as in Example 1 except that the amount of the raw material mixture was changed to the amount shown in Table 1. Next, the prepared raw material mixture was filled in a round mortar made of mullite (manufactured by Toshiba Ceramics Co., Ltd., R2013, inner diameter 13 cm), placed in an electric heating furnace, heated in an air atmosphere, and heated at a temperature of 1020 ° C. It was held for a time and fired. After cooling the obtained block-like fired product and the mortar in the air, by turning the mortar upside down, it was confirmed whether the baked powder and the firing container were firmly fixed. It was confirmed that it dropped without peeling and did not adhere. The obtained block-like fired product was pulverized and classified to obtain lithium cobaltate powder. The average particle diameter, BET specific surface area, silicon content, fluorine content and residual alkali content of the obtained lithium cobalt oxide powder were measured. The measurement results are shown in Table 2.

(Examples 5-8, Comparative Examples 7-12)
<Battery performance test>
(1) Production of lithium secondary battery;
91% by mass of lithium cobaltate obtained in Examples 1 to 4 and Comparative Examples 1 to 6, 6% by mass of graphite powder, and 3% by mass of polyvinylidene fluoride were mixed to obtain a positive electrode agent, which was used as N-methyl-2- A kneaded paste was prepared by dispersing in pyrrolidinone. The prepared kneaded paste was applied to an aluminum foil, dried, pressed and punched into a disk having a diameter of 15 mm to obtain a positive electrode plate.

Using this positive electrode plate, a lithium secondary battery was manufactured using each member such as a separator, a negative electrode, a positive electrode, a current collector plate, a mounting bracket, an external terminal, and an electrolytic solution. Among these, a metal lithium foil was used for the negative electrode, and 1 mol of LiPF ₆ was dissolved in 1 liter of a 1: 1 kneaded solution of ethylene carbonate and ethyl methyl carbonate as the electrolyte.
(2) Battery performance evaluation The produced lithium secondary battery was operated at room temperature under the following conditions, and the following battery performance was evaluated.

<Evaluation of cycle characteristics>
After charging the positive electrode to 4.3V by constant current voltage (CCCV) charging at 1.0C for 5 hours, charging / discharging to discharge to 2.7V at a discharge rate of 0.2C is performed. As one cycle, discharge capacity (unit: mAH / g) and electric energy (unit: mWH / g) were measured for each cycle. This cycle is repeated 20 cycles, and from the respective discharge capacities and electric energy of the first cycle and the 20th cycle, the following formula:
Discharge capacity retention rate (%) = (Discharge capacity at 20th cycle / Discharge capacity at 1st cycle) × 100
Electric energy maintenance rate (%) = (electric energy at 20th cycle / electric energy at 1st cycle) × 100
Thus, the discharge capacity maintenance rate and the power amount maintenance rate were calculated. The discharge capacity at the first cycle was the initial discharge capacity, and the electric energy at the first cycle was the initial electric energy.

  From the results of Tables 2 and 3, the lithium cobaltate obtained in Examples 1 to 4 did not adhere to the firing vessel, had high initial discharge capacity, and high cycle characteristics. As for the lithium cobaltate obtained in 1 to 6, those having high cycle characteristics were not obtained. Further, in Comparative Examples 1, 4 and 5, adhesion to the firing container occurred.

Claims (7)

  A lithium transition metal composite oxide for a lithium ion secondary battery positive electrode active material, wherein the content of silicon atoms is 100 to 1000 ppm and the content of fluorine atoms is 300 to 900 ppm.   Lithium compound, transition metal compound, fluorine compound and silicon compound are mixed to obtain a raw material mixture, and then the raw material mixture is fired to obtain a lithium transition metal composite oxide. Manufacturing method. Method for producing the fluorine _{compound, LiF, CaF 2, MgF 2} , CoF 2 and lithium transition metal composite oxide according to claim 2, characterized in that one or more compounds selected from AlF ₃ . The silicon compound is SiO _x (wherein x is 1 ≦ x ≦ 2) or M _y SiO _z (wherein M is selected from Li, H, Co, Ni, Mn, Mg and Al). The element of a seed | species or more is shown, y is 0 <y <= 4, z is 2 <z <= 4.) The manufacture of lithium transition metal complex oxide of Claim 2 or 3 characterized by the above-mentioned. Method.   In the raw material mixture, the mixing amount of the silicon compound is the ratio of the number of moles of fluorine atoms (F) in the fluorine compound to the total number of moles of silicon atoms (Si) in the raw material mixture (molar ratio F / Si). Is a quantity which becomes 0.5-20, The manufacturing method of the lithium transition metal complex oxide of any one of Claims 2-4 characterized by the above-mentioned.   A lithium-ion secondary battery positive electrode active material comprising the lithium-transition metal composite oxide for a lithium-ion secondary battery positive electrode active material according to claim 1.   A lithium ion secondary battery obtained by using the positive electrode active material for a lithium ion secondary battery according to claim 6.