JP2011146309A - Positive electrode active material of nonaqueous electrolyte secondary battery, its manufacturing method, and nonaqueous electrolyte secondary battery using positive electrode active material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a positive electrolyte secondary battery of a nonaqueous electrolyte secondary battery capable of improving industrial mass productivity without spoiling battery performance. <P>SOLUTION: In a process of calcining a mixture obtained by mixing a nickel complex compound having an average particle diameter of 8-20 μm, and a lithium compound and having bulk density of 1.0-2.2 g/ml by filling up in a calcination container, when thickness at the time of inserting the mixture into the calcination container is set up to be t (mm), a time for retaining temperature of the mixture at a temperature range of 550-650°C is set up to be the minimum retention time or more calculated from formula of time (minute) equal to 0.026t<SP>2</SP>-2.7. Upon performing calcination in an acid atmosphere where oxygen concentration is 60 vol.% or more, the positive electrode active material made from lithium-nickel complex oxide can be attained by washing the attained calcined object with water. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a positive electrode active material composed of a lithium nickel composite oxide and applied to a positive electrode of a non-aqueous electrolyte secondary battery, a manufacturing method thereof, and a non-aqueous electrolyte secondary battery using the positive electrode active material.

  In recent years, with the advancement of electronic technology, electronic devices are rapidly becoming smaller and lighter. In particular, as portable electronic devices such as mobile phones and notebook PCs have become popular and highly functional, the development of small, lightweight batteries with high energy density has become strong as portable power sources used in these devices. It is desired.

  A lithium ion secondary battery, which is a non-aqueous electrolyte secondary battery, is already used as a power source for portable electronic devices because of its small size and high energy. In addition to such applications, research and development aimed at using lithium-ion secondary batteries as large-scale power sources such as hybrid vehicles and electric vehicles are being promoted.

A lithium cobalt composite oxide (LiCoO ₂ ), which is relatively easy to synthesize, is used as the positive electrode active material of the lithium ion secondary battery, but a rare and expensive cobalt is used as a raw material for the lithium cobalt composite oxide. Since a compound is used, it causes a cost increase of the positive electrode active material.

  Lowering the cost of the positive electrode active material and realizing the manufacture of cheaper lithium ion secondary batteries can be achieved by reducing the cost of portable electronic devices that are currently in widespread use and installing lithium ion secondary batteries in future large-scale power supplies Therefore, it can be said that it has significant industrial significance.

Another positive electrode material that can be applied as a positive electrode active material for a lithium ion secondary battery is lithium nickel composite oxide (LiNiO ₂ ). Lithium-nickel composite oxides have the advantages that they have a higher capacity than the current mainstream lithium-cobalt composite oxides, and that nickel as a raw material is cheaper and more stable than cobalt. Therefore, it is expected to be a next-generation positive electrode material, and research and development of lithium-nickel composite oxides are being continued actively.

  However, since the lithium nickel composite oxide begins to decompose at a lower temperature than the lithium cobalt composite oxide, the firing temperature at the time of synthesis cannot be increased, resulting in a longer firing time and industrial mass production. It has a problem that it is inferior in productivity.

  About the manufacturing method of lithium nickel complex oxide, as shown in patent documents 1-4, the method of mixing and heat-treating a lithium compound and a nickel complex compound is taken. These documents disclose that the synthesis time, synthesis temperature, synthesis atmosphere, and the like are defined for the purpose of improving battery characteristics. However, in the industrial mass production process, synthesis is completed in as short a time as possible without impairing battery performance, and conditions for improving productivity have not been studied. Based on these technologies, It is difficult to dramatically increase the productivity when mass-producing industrially.

Japanese Patent Application Laid-Open No. 07-114915 JP-A-11-111290 JP 2000-133249 A JP 2007-119266 A

  The present invention has been made paying attention to such problems, and a positive electrode active material for a non-aqueous electrolyte secondary battery that provides high battery performance is high in an industrial mass production process without impairing battery performance. It is to provide with productivity.

  Another object of the present invention is to provide a non-aqueous electrolyte secondary battery having a high initial discharge capacity and a positive electrode active material as a positive electrode material of the battery in an industrial mass production process.

  In order to solve the above problems, the present inventor has conducted research on the synthesis of a positive electrode active material. As a result, in the firing of the lithium nickel composite oxide used as the positive electrode active material, a specific temperature region maintained during heating is It has a great influence on the characteristics of the positive electrode active material, and in this temperature range, by ensuring the oxygen diffusion time according to the thickness of the mixture of lithium compound and nickel composite compound, the battery performance is not impaired. The present invention has been completed with the knowledge that the productivity of the positive electrode active material can be greatly improved in a typical mass production process.

That is, the method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery according to the present invention relates to a method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery composed of a lithium nickel composite oxide. In a step of filling a firing container with a mixture having a bulk density of 1.0 to 2.2 g / ml obtained by mixing a nickel composite compound having a particle size of 8 to 20 μm and a lithium compound and firing the mixture. The time when the temperature of the mixture is maintained in the temperature range of 550 ° C. or more and 650 ° C. or less when the thickness when the mixture is put in the baking container is t (mm) is expressed by the formula: time (minute) = 0.026t ² -2.7 The minimum holding time or more required by 2.7, wherein the mixture is fired in an oxidizing atmosphere having an oxygen concentration of 60% by volume or more, and the obtained fired product is washed with water. To do.

  It is preferable to keep the mixture in the temperature region in an atmosphere having an oxygen concentration of 80% by volume or more.

  In the firing step, it is preferable that the maximum temperature reached by the mixture is 650 ° C. or higher and 800 ° C. or lower and the holding time at the maximum temperature is 4 hours or longer.

  Moreover, in the said baking process, it is preferable that the time from the heating start of the said mixture to completion of cooling is 24 hours or less.

  It is preferable to use lithium hydroxide or lithium hydroxide hydrate as the lithium compound, and it is preferable to use nickel composite oxide or nickel composite hydroxide as the nickel composite compound.

The method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery of the present invention is widely applied to the production of a positive electrode active material composed of a lithium nickel composite oxide. In particular, the general formula: Li _x Ni _{(1 -yz)} Co _y M _z O ₂ (wherein M represents at least one element selected from Al and Ti, and x, y, and z are 0.90 ≦ x ≦ 1.10. , 0.05 ≦ y ≦ 0.35, 0.005 ≦ z ≦ 0.15) is suitably applied when obtaining a lithium nickel composite oxide having a composition represented by:

  The method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery according to the present invention provides a positive electrode active material that is produced with high productivity in an industrial mass production process while having characteristics capable of maintaining high battery performance. .

  Furthermore, by using the positive electrode active material of the present invention as a positive electrode material, for example, in the case of a non-aqueous electrolyte secondary battery comprising a 2032 type coin battery, the first discharge capacity is 198 mAh / g or more. A non-aqueous electrolyte secondary battery having a high initial discharge capacity is provided with high productivity in an industrial mass production process.

  According to the present invention, in an industrial mass production process of a non-aqueous electrolyte secondary battery and a positive electrode active material used as the positive electrode material, high battery performance and high productivity can be achieved simultaneously. Industrial value of the present invention Is extremely large.

FIG. 1 is a perspective view and a cross-sectional view showing a coin battery used for battery evaluation. FIG. 2 is a graph showing the relationship between the thickness of the mixture and the first discharge capacity with respect to the holding time of 550 to 650 ° C.

  Hereinafter, embodiments of the present invention will be described in detail.

(1) Positive electrode active material for non-aqueous electrolyte secondary battery and manufacturing method thereof When producing lithium nickel composite oxide, which is a positive electrode material for a lithium ion battery, industrially, generally in a ceramic firing container The filled raw material mixture is continuously fed into a furnace such as a roller hearth kiln or a pusher furnace, and baked at a predetermined temperature for a predetermined time to cause a synthesis reaction.

  As a baking container in an industrial production process, the inner dimension is generally in a range of 100 mm (L) × 100 mm (W) × 20 mm (H) to 500 mm (L) × 500 mm (W) × 100 mm (H). A certain container is used, and a mixture of a lithium compound and a nickel composite compound as raw materials is filled so as to have a thickness in the range of 5 to 100 mm.

  In this case, as means for improving the productivity, the transport speed is increased to shorten the time for passing through the furnace, or the amount of the mixture put into the baking container is increased, so that the unit time per unit time is increased. It is conceivable to increase the amount of synthesis.

  Among these methods, the method of increasing the conveyance speed has a problem that if the speed is increased too much, the time for the synthesis reaction is insufficient, and crystal growth that can be used as the positive electrode material is not performed, and the battery performance is deteriorated.

  On the other hand, if the amount of the mixture filled in the firing container is too large, the thickness of the mixture becomes too large, and the diffusion of oxygen necessary for the reaction to the bottom of the container becomes insufficient, as shown in the following formula (1). Reaction does not proceed, the synthesis of the lithium nickel composite oxide is insufficient, and problems such as a decrease in discharge capacity occur.

2NiO + 2LiOH + 1 / 2O ₂ → 2LiNiO ₂ + H ₂ O (1)

  Therefore, in order to improve the battery performance, in synthesizing the lithium nickel composite oxide used as the positive electrode active material, oxygen necessary for the reaction between the nickel composite oxide and the lithium compound should be sufficiently diffused in the mixture. Necessary.

  Here, in the reaction of the nickel composite oxide and the lithium compound, the inventors do not need to sufficiently diffuse oxygen into the mixture in the entire temperature range in the firing step, and the most important temperature for such a reaction. It was found that if there is a region and oxygen is sufficiently diffused into the mixture in this temperature region, a lithium nickel composite oxide with good battery performance can be obtained.

  That is, when the mixture filled in the firing container is fired to obtain the lithium nickel composite oxide, it is put into the firing container as long as the oxygen diffusion time according to the thickness of the mixture is secured in the above temperature range. Even if the amount of the mixture is increased (thickness of the mixture is increased), a lithium nickel composite oxide can be obtained that does not deteriorate the battery performance and can be made a battery with a high discharge capacity. .

More specifically, the method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery of the present invention is a method for producing a positive electrode active material composed of a lithium nickel composite oxide, and has an average particle size of 8 to In a step of filling a firing container with a bulk density of 1.0 to 2.2 g / ml obtained by mixing a nickel composite compound having a thickness of 20 μm and a lithium compound, and firing the mixture, The time when the temperature of the mixture is maintained in the temperature range of 550 ° C. or more and 650 ° C. or less when the thickness when put in the baking container is t (mm) is expressed by the formula: time (minutes) = 0.026 t. as above minimum age required by ² -2.7, oxygen concentration and fired in the mixture in an oxidizing atmosphere for more than 60 volume%, it is characterized by washing the obtained fired product.

  The present inventors have obtained knowledge that it is important to sufficiently supply oxygen to a mixture in a temperature range where the temperature of the mixture is 550 ° C. or more and 650 ° or less. That is, although depending on the type of lithium compound, the solid-phase solid-phase reaction or the liquid-phase solid-phase reaction between the lithium compound and the nickel composite compound progressed most significantly in the temperature range of 550 to 650 ° C. In this temperature range, the oxygen necessary for the reaction is sufficiently distributed throughout the mixture, whereby a lithium nickel composite oxide that provides high battery performance can be obtained.

  For example, when lithium hydroxide and nickel composite oxide are used as raw materials, these reactions start from around 450 ° C. The melting point of lithium hydroxide is around 480 ° C., and the lithium hydroxide reacts with the nickel composite oxide while melting. In this temperature region, if sufficient oxygen diffusion is not performed to the bottom of the firing vessel, the unreacted molten lithium hydroxide reacts with the ceramic vessel, so that it is substantially combined with the nickel composite oxide. The amount of lithium is insufficient, and crystals that inhibit the battery reaction are mixed in the produced lithium nickel composite oxide, leading to a decrease in battery performance.

  However, the reaction rate is slow near the reaction start temperature, and the reaction proceeds as the temperature of the raw material mixture rises. Therefore, even if the reaction mixture is held near the reaction start temperature, the efficiency is poor. Therefore, in a temperature range that is higher than the reaction start temperature and at which a sufficient reaction rate is obtained by melting lithium hydroxide, that is, a temperature at which the mixture becomes 550 ° C. or higher, oxygen is sufficiently supplied and the reaction proceeds significantly. is important.

  On the other hand, when the temperature of the mixture reaches 650 ° C., when unreacted lithium hydroxide and nickel composite oxide still exist and oxygen is insufficient, the side reaction of the following formula (2) is performed. Since a heterogeneous phase that prevents the movement of Li ions during the battery reaction occurs in the generated lithium nickel composite oxide crystal, the battery performance is deteriorated.

8NiO + 2LiOH + 1 / 2O ₂ → Li ₂ Ni ₈ O ₁₀ + H ₂ O (2)

Here, when baking is performed by filling the mixture in the baking container, as the thickness of the mixture increases, from the upper opening side of the baking container, that is, the upper surface of the mixture, to the bottom part of the baking container, that is, the bottom part of the mixture It becomes difficult for oxygen to diffuse, and it is necessary to secure time for oxygen diffusion according to the thickness of the mixture under a constant oxygen partial pressure. As a result of the study, the present inventor has experimentally obtained the knowledge that the thickness t (mm) of the mixture and the retention time required for oxygen diffusion are in a predetermined relationship. That is, the minimum required holding time (minutes) is derived from the formula: time (minutes) = 0.026 t ² −2.7.

  If the time for holding the mixture in the temperature range of 550 ° C. or more and 650 ° C. or less is less than the minimum holding time, when the mixture is used as a positive electrode material for a non-aqueous electrolyte secondary battery comprising a 2032 type coin battery, the non-aqueous electrolyte 2 is used. The first discharge capacity of the secondary battery does not exceed 198 mAh / g. If the holding time in such a temperature range is further increased, the first discharge capacity of the obtained battery is further improved. However, the holding time is selected as a time longer than the minimum holding time from the required battery performance and energy cost. be able to. Note that the presence of the mixture in the temperature range can be confirmed by actual measurement using a thermocouple or the like.

  Thus, by passing through a temperature range of 550 ° C. or more and 650 ° C. or less with a minimum holding time not less than the time derived from the above formula, the positive electrode active material that is most productive and does not impair battery performance can be efficiently obtained. It becomes possible to produce.

  Specifically, the minimum holding time is about 40 minutes when the thickness t of the mixture is 40 mm, about 50 minutes when 45 mm, about 62 minutes when 50 mm, about 76 minutes and 60 mm when 55 mm. In the case of 65 mm, it takes about 107 minutes, and in the case of 70 mm, it takes about 125 minutes.

  It should be noted that the above formula can be applied over the above-described normally used firing container and the entire range of the normal filling amount.

  By the way, in the temperature range of 550 ° C. or more and 650 ° C. or less, even when the temperature is kept at a certain temperature within the range of the temperature, the temperature is changed within that range, for example, when the temperature is raised at a constant speed. Even in such a case, the same effect can be obtained.

  In addition, since this reaction basically requires oxygen, it is needless to say that a higher oxygen concentration in the firing furnace is preferable. The firing process is performed in an atmosphere (oxygen, oxygen gas, etc.) containing oxygen throughout, but in the present invention, the oxygen concentration in the firing furnace is set to 60% by volume or more. This is because when the oxygen concentration in the firing step is less than 60% by volume, the reaction between the lithium compound and the nickel composite compound is changed from the oxygen diffusion rate-determining method to the oxygen concentration-limiting method, and the reaction does not proceed sufficiently.

  In the present invention, it is preferable that the oxygen concentration in the firing furnace is at least 80% by volume at least in a temperature range of 550 ° C. or more and 650 ° C. or less where the reaction is particularly remarkable. In this case, when the oxygen concentration in the firing furnace is less than 80% by volume, the bottom of the firing container is exceeded even when the holding time in the temperature region is secured beyond the time derived from the above formula. There is a possibility that oxygen does not diffuse sufficiently to the part. For this reason, in order to prevent reliably that a heterogeneous phase arises in a baked product and causes deterioration of battery performance due to insufficient diffusion, the oxygen concentration is preferably 80% by volume.

  If the reaction is carried out in the above temperature range for a time longer than that derived from the above formula, the basic reaction is completed and a lithium nickel composite oxide is obtained. However, in order to exhibit sufficient crystallinity and high battery performance in the synthesis of the lithium nickel composite oxide, it is preferable that the maximum temperature of the mixture in the firing is 650 ° C. or more and 800 ° C. or less, and the maximum temperature is reached. The time for holding the mixture is preferably 4 hours or more. If the maximum temperature reached is less than 650 ° C, or if the retention time is less than 4 hours even if the temperature is higher than the temperature, the resulting lithium nickel composite oxide may not have sufficient crystallinity. When it exceeds, the produced lithium nickel composite oxide starts to decompose, and the layered structure may be disturbed to deteriorate the battery performance. The holding time at the maximum temperature is preferably 8 hours or less in consideration of the entire baking time. Moreover, the retention of the mixture at the maximum temperature can be confirmed by actual measurement using a thermocouple or the like.

  If synthesis is performed over a certain period of time, it is possible to maintain sufficient crystallinity and synthesize without impairing the battery performance. It is not preferable to make it longer. Therefore, cooling is completed until the baking container containing the mixture enters the furnace for baking and comes out, that is, reaches the maximum temperature from the start of heating and holds it (the temperature of the baking product is 150 ° C.). It is preferable that the time (firing time) of the whole process until it becomes (C or less) be 24 hours or less. On the other hand, if the temperature is rapidly increased, the temperature of the mixture in the baking container becomes non-uniform and the reaction may not be uniform. Therefore, the time from the start of heating to the completion of cooling (baking time) is 12 hours or more. It is preferable that

  In the manufacturing method of this invention, the average particle diameter of the nickel composite oxide used as the raw material of the said mixture shall be in the range of 8-20 micrometers. When the average particle size is less than 8 μm, the particle size of the obtained positive electrode active material is also small, the filling amount per volume is small, and the capacity of the battery is reduced. Further, sintering is likely to occur during firing, and a coarse positive electrode active material is generated, resulting in deterioration of battery characteristics. On the other hand, even if the average particle diameter exceeds 20 μm, there are few contacts between the positive electrode active materials, the resistance of the positive electrode is increased, and the battery capacity is decreased. In addition, the bulk density of the mixture obtained by mixing the nickel composite compound and the lithium compound is set in the range of 1.0 to 2.2 g / ml. When the bulk density is less than 1.0 g / ml, the necessary capacity of the firing container necessary for filling a certain amount into the firing container becomes too large, and the productivity is remarkably lowered. On the other hand, when the bulk density exceeds 2.2 g / ml, the mixture is densely packed, so that the oxygen diffusion is slowed down, and the time required for firing is extended to reduce the productivity.

  The lithium compound used as a raw material of the mixture is not particularly limited, but lithium hydroxide or lithium carbonate is preferable, and lithium hydroxide or lithium hydroxide hydrate having a melting point near 480 ° C. is a nickel composite oxide. In view of the reaction with This is because lithium hydroxide melts and reacts with the nickel composite oxide in a solid-liquid reaction, so that the reaction proceeds more uniformly.

  Further, the nickel composite compound used as a raw material of the mixture is not particularly limited, but nickel composite hydroxide or nickel composite oxide is preferable from the viewpoint that no side reaction product other than water is generated during the reaction.

  In the production method of the present invention, the lithium nickel composite oxide obtained by firing is washed with water, so that excess lithium on the surface of the lithium nickel composite oxide particles is removed, and the high capacity and high safety of the non-aqueous electrolyte 2 is obtained. It becomes a positive electrode active material for a secondary battery. Here, a known technique is used as the water washing method.

  For example, as a slurry concentration at the time of washing with water, it is preferable that 0.5 to 2 of lithium nickel composite oxide is added to water 1 by mass ratio, and excess lithium on the surface of lithium nickel composite oxide particles is sufficiently removed. While stirring, after stirring, solid-liquid separation may be performed and dried. When the slurry concentration exceeds 2 by mass, the viscosity is very high and stirring becomes difficult, and because the alkali in the liquid is high, the dissolution rate of the deposit is slowed or peeled off due to equilibrium. May be difficult to separate from the powder. On the other hand, if the slurry concentration is less than 0.5 by mass ratio, the amount of lithium elution is large because it is too dilute, and lithium is desorbed from the crystal lattice of the positive electrode active material, so that the crystal is easily broken. The aqueous solution having a high pH absorbs carbon dioxide in the atmosphere and reprecipitates lithium carbonate.

  Although the water used for the said water washing is not specifically limited, The water of less than 10 microsiemens / cm is preferable by electrical conductivity measurement, and the water of 1 microsiemens / cm or less is more preferable. That is, by using water of less than 10 μS / cm in electrical conductivity measurement, it is possible to prevent a decrease in battery performance due to adhesion of impurities to the positive electrode active material.

  It is preferable that the amount of adhering water remaining on the particle surface during the solid-liquid separation of the slurry is small. When there is much adhering water, the lithium melt | dissolved in the liquid will reprecipitate and the amount of lithium which exists on the surface of the lithium nickel composite oxide powder after drying will increase. For solid-liquid separation, a commonly used centrifuge, filter press, or the like is used.

  Although the temperature of drying is not specifically limited, Preferably it is 80-550 degreeC, More preferably, it is 120-350 degreeC. The reason why the temperature is set to 80 ° C. or higher is to quickly dry the positive electrode active material after washing with water and prevent a gradient of lithium concentration from occurring between the particle surface and the inside of the particle. On the other hand, near the surface of the positive electrode active material, it is expected that it is very close to the stoichiometric ratio, or is slightly desorbed from lithium and close to the charged state. As a result, the crystal structure of the powder that is close to is broken, and the electrical characteristics may be deteriorated. Furthermore, considering productivity and thermal energy cost, 120 to 350 ° C. is more preferable. At this time, as a drying method, it is preferable to perform the filtered powder at a predetermined temperature using a dryer that can be controlled in a gas atmosphere not containing a compound component containing carbon and sulfur or in a vacuum atmosphere.

The present invention can be applied to industrial production of a positive electrode active material for a non-aqueous electrolyte secondary battery composed of various lithium-nickel composite oxides. : Li _x Ni _(1-yz) Co _y M _z O ₂ (wherein M represents at least one element selected from Al and Ti, and x, y, and z are each 0.90 ≦ x ≦ 1.10, 0.05 ≦ y ≦ 0.35, and 0.005 ≦ z ≦ 0.15).

  The nickel composite hydroxide or nickel composite oxide, which is a raw material for the lithium nickel composite oxide, can be obtained based on a known method. For example, a nickel composite hydroxide can be obtained by coprecipitation of nickel, cobalt, and additive element M. Furthermore, by oxidizing and baking the nickel composite hydroxide, a nickel composite oxide in which cobalt and the additive element M are dissolved in nickel oxide can be obtained. However, it can be obtained by other means such as pulverizing and mixing nickel oxide and oxides of other additive elements.

  The positive electrode active material for a non-aqueous electrolyte secondary battery provided by the present invention is obtained by the above-described manufacturing method. When used in a non-aqueous electrolyte secondary battery, the battery has a high capacity and high safety. It becomes.

  In particular, the positive electrode active material for a non-aqueous electrolyte secondary battery according to the present invention has a discharge capacity of 198 mAh / g or more at the first discharge of the non-aqueous electrolyte secondary battery when this is used as a positive electrode material. This makes it possible to industrially produce a high-capacity nonaqueous electrolyte secondary battery.

For example, a 2032 type coin battery can be used for the first measurement of the discharge capacity. As this 2032 type coin battery, 90% by mass of active material powder was mixed with 5% by mass of acetylene black and 5% by mass of polyvinylidene fluoride (PVDF), and the resulting mixture was mixed with N-methyl-2-pyrrolidone (NMP). The paste obtained was applied to a 20 μm thick aluminum foil so that the mass of the active material after drying was 0.05 g / cm ² , vacuum-dried at 120 ° C., and then a 1 cm diameter circle A positive electrode obtained by punching into a plate, a negative electrode made of lithium metal, and an electrolytic solution comprising an equivalent mixed solution of ethylene carbonate (EC) and diethyl carbonate (DEC) using 1 mol / L LiClO ₄ as a supporting salt; , A glove box in an argon atmosphere using a separator made of polyethylene and impregnated with the electrolytic solution, the dew point of which is controlled at -80 ° C In use a disk produced by assembling them.

In the measurement, the fabricated secondary battery was left for about 24 hours to stabilize the open circuit voltage (OCV), the current density with respect to the positive electrode was set to 0.5 mA / cm ² , and the cutoff voltage was 4.3 to 3. A charge / discharge test is performed at 0V.

  The non-aqueous electrolyte secondary battery of the present invention is characterized in that the above-described positive electrode active material of the present invention is applied as a positive electrode material. Hereinafter, the nonaqueous electrolyte secondary battery of the present invention will be described.

  The nonaqueous electrolyte secondary battery of the present invention is a positive electrode active material comprising the above lithium nickel composite oxide, in particular, using the lithium nickel composite oxide obtained by the above production method as a positive electrode active material, producing a positive electrode, This is a non-aqueous electrolyte secondary battery with high capacity and high safety.

  Here, although the manufacturing method of the positive electrode used for the nonaqueous electrolyte secondary battery of this invention is demonstrated, it does not specifically limit to this. For example, a positive electrode in which a positive electrode mixture containing positive electrode active material particles and a binder is supported on a belt-like positive electrode core material (positive electrode current collector) is produced. In addition, the positive electrode mixture can also contain an additive such as a conductive material as an optional component. The positive electrode mixture is supported on the core material by dispersing the positive electrode mixture in a liquid component to prepare a paste, coating the paste on the core material, and drying the paste.

As the binder of the positive electrode mixture, either a thermoplastic resin or a thermosetting resin may be used, but a thermoplastic resin is preferable. Examples of the thermoplastic resin include polyethylene, polypropylene, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), styrene butadiene rubber, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and tetrafluoroethylene- Perfluoroalkyl vinyl ether copolymer (PFA), vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoro Ethylene (PCTFE), vinylidene fluoride-pentafluoropropylene copolymer, propylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer (ECTF) ), Vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene -A methyl acrylate copolymer, an ethylene-methyl methacrylate copolymer, etc. are mentioned. These may be used alone or in combination of two or more. These may be cross-linked products of Na ⁺ ions and the like.

  The conductive material of the positive electrode mixture may be any electron conductive material that is chemically stable in the battery. For example, graphite such as natural graphite (such as flake graphite), artificial graphite, carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black and thermal black, and conductive such as carbon fiber and metal fiber Use conductive fibers, metal powders such as aluminum, conductive whiskers such as zinc oxide and potassium titanate, conductive metal oxides such as titanium oxide, organic conductive materials such as polyphenylene derivatives, carbon fluoride, etc. Can do. These may be used alone or in combination of two or more.

  The addition amount of the conductive material of the positive electrode mixture is not particularly limited, and is preferably 0.5 to 50% by mass with respect to the positive electrode active material particles contained in the positive electrode mixture, and 0.5 to 30%. % By mass is more preferable, and 0.5 to 15% by mass is more preferable.

  The positive electrode core material (positive electrode current collector) may be any electron conductor that is chemically stable in the battery. For example, a foil or sheet made of aluminum, stainless steel, nickel, titanium, carbon, conductive resin, or the like can be used, and among these, aluminum foil and aluminum alloy foil are more preferable. Here, a carbon or titanium layer or an oxide layer can be formed on the surface of the foil or sheet. Further, irregularities can be imparted to the surface of the foil or sheet, and a net, a punching sheet, a lath body, a porous body, a foamed body, a fiber group molded body, and the like can also be used.

  The thickness of the positive electrode core material is not particularly limited, and for example, a thickness of 1 to 500 μm can be used.

  Next, components other than the positive electrode used in the nonaqueous electrolyte secondary battery of the present invention will be described. However, the nonaqueous electrolyte secondary battery of the present invention is characterized in that the positive electrode active material is used, and other components are not particularly limited.

  First, as the negative electrode, those capable of charging and discharging lithium are used. For example, a negative electrode mixture containing a negative electrode active material and a binder and a conductive material and a thickener as optional components is used as a negative electrode core material. What was carried can be used. Such a negative electrode can be produced in the same manner as the positive electrode.

  The negative electrode active material may be any material that can electrochemically charge and discharge lithium. For example, graphites, non-graphitizable carbon materials, lithium alloys and the like can be used. The lithium alloy is preferably an alloy containing at least one element selected from the group consisting of silicon, tin, aluminum, zinc and magnesium.

  The average particle diameter of the negative electrode active material is not particularly limited, and, for example, one having an average particle diameter of 1 to 30 μm is used.

As the binder of the negative electrode mixture, either a thermoplastic resin or a thermosetting resin may be used, but a thermoplastic resin is preferable. Examples of the thermoplastic resin include polyethylene, polypropylene, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), styrene butadiene rubber, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and tetrafluoroethylene- Perfluoroalkyl vinyl ether copolymer (PFA), vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoro Ethylene (PCTFE), vinylidene fluoride-pentafluoropropylene copolymer, propylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer (ECTF) ), Vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene -A methyl acrylate copolymer, an ethylene-methyl methacrylate copolymer, etc. are mentioned. These may be used alone or in combination of two or more. These may be cross-linked products of Na ⁺ ions and the like.

  The conductive material of the negative electrode mixture may be any electron conductive material that is chemically stable in the battery. For example, graphite such as natural graphite (such as flake graphite), artificial graphite, carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black and thermal black, and conductive such as carbon fiber and metal fiber For example, conductive fibers, metal powders such as copper and nickel, and organic conductive materials such as polyphenylene derivatives can be used. These may be used alone or in combination of two or more.

  The addition amount of the conductive material is not particularly limited, and is preferably 1 to 30% by mass and more preferably 1 to 10% by mass with respect to the negative electrode active material particles contained in the negative electrode mixture.

  The negative electrode core material (negative electrode current collector) may be any electronic conductor that is chemically stable in the battery. For example, a foil or sheet made of stainless steel, nickel, copper, titanium, carbon, conductive resin, or the like can be used, and copper and a copper alloy are preferable. On the surface of the foil or sheet, a layer of carbon, titanium, nickel or the like can be provided, or an oxide layer can be formed. Further, irregularities can be imparted to the surface of the foil or sheet, and a net, a punching sheet, a lath body, a porous body, a foamed body, a fiber group molded body, and the like can also be used.

  The thickness of the said negative electrode core material is not specifically limited, For example, the thickness of 1-500 micrometers is used.

  Next, as the non-aqueous electrolyte, a non-aqueous solvent in which a lithium salt is dissolved is preferable. Non-aqueous solvents include, for example, cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), dimethyl carbonate (DMC). ), Chain carbonates such as diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dipropyl carbonate (DPC), aliphatic carboxylic acid esters such as methyl formate, methyl acetate, methyl propionate, ethyl propionate, Lactones such as γ-butyrolactone and γ-valerolactone, chain ethers such as 1,2-dimethoxyethane (DME), 1,2-diethoxyethane (DEE), ethoxymethoxyethane (EME), tetrahydrofuran, 2 -Methyltetrahydrofuran etc. Cyclic ethers, dimethyl sulfoxide, 1,3-dioxolane, formamide, acetamide, dimethylformamide, dioxolane, acetonitrile, propylnitrile, nitromethane, ethyl monoglyme, phosphoric acid triester, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, ethyl ether, 1,3-propane sultone, anisole, dimethyl sulfoxide, N-methyl-2- Pyrrolidone or the like can be used. These may be used alone, but it is preferable to use a mixture of two or more. Among these, a mixed solvent of a cyclic carbonate and a chain carbonate, or a mixed solvent of a cyclic carbonate, a chain carbonate, and an aliphatic carboxylic acid ester is preferable.

Examples of the lithium salt include LiClO ₄ , LiBF ₄ , LiPF ₆ , LiAlCl ₄ , LiSbF ₆ , LiSCN, LiCl, LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , Li (CF ₃ SO ₂ ) ₂ , LiAsF ₆ , LiN. (CF ₃ SO ₂ ) ₂ , LiB ₁₀ Cl ₁₀ , lower aliphatic lithium carboxylate, LiCl, LiBr, LiI, lithium chloroborane, lithium tetraphenylborate, lithium imide salt and the like can be mentioned. These may be used alone or in combination of two or more. It is preferable to use at least LiPF ₆ .

  The lithium salt concentration in the non-aqueous solvent is not particularly limited, but is preferably 0.2 to 2 mol / L, and more preferably 0.5 to 1.5 mol / L.

  Various additives can be added to the non-aqueous electrolyte in order to improve the charge / discharge characteristics of the battery. Examples of additives include triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, pyridine, hexaphosphoric triamide, nitrobenzene derivatives, crown ethers, quaternary ammonium salts, ethylene glycol dialkyl ether, and the like. be able to.

  A separator is interposed between the positive electrode and the negative electrode. As the separator, a microporous thin film having a high ion permeability, a predetermined mechanical strength, and an insulating property is preferable. The microporous thin film preferably has a function of closing the pores at a certain temperature or higher and increasing the resistance. As a material for the microporous thin film, polyolefin such as polypropylene and polyethylene having excellent resistance to organic solvents and hydrophobicity is preferably used. In addition, a sheet made of glass fiber or the like, a nonwoven fabric, a woven fabric, or the like is also used.

  The pore diameter of the separator is, for example, 0.01 to 1 μm. Moreover, generally the thickness of a separator is 10-300 micrometers. Moreover, the porosity of the separator is generally 30 to 80%.

  Furthermore, a non-aqueous electrolyte and a polymer electrolyte made of a polymer material that holds the non-aqueous electrolyte can be used as a separator integrated with a positive electrode or a negative electrode. The polymer material is not particularly limited as long as it can hold the nonaqueous electrolytic solution, but a copolymer of vinylidene fluoride and hexafluoropropylene is particularly preferable.

  The positive electrode, negative electrode, separator, and non-aqueous electrolyte solution that have been described above can be used, and the non-aqueous electrolyte secondary battery according to the present invention can have various shapes such as a cylindrical type and a laminated type.

  In any case, the positive electrode and the negative electrode are laminated via a separator to form an electrode body, and the electrode body is impregnated with the non-aqueous electrolyte solution. A current collector lead or the like is used to connect between the positive electrode current collector and the positive electrode terminal communicating with the outside, and between the negative electrode current collector and the negative electrode terminal communicating with the outside. The battery having the above structure can be sealed in a battery case to complete the battery.

  Examples of the present invention will be specifically described below.

Example 1
In order to synthesize the positive electrode active material, a commercial lithium hydroxide monohydrate (LiOH.H ₂ O) and a solid solution of nickel, cobalt, and aluminum at a molar ratio of 82: 15: 3 were obtained. After weighing a metal composite hydroxide (Ni _0.82 Co _0.15 Al _0.03 O ₂ ) having a thickness of 15 μm so that the molar ratio of lithium to a metal other than lithium is 1.02: 1.00, Mixed. In addition, the bulk density of the obtained mixed powder was 1.1 g / ml.

  This mixed powder is charged into a firing container having an internal size of 301 mm (L) × 301 mm (W) × 102 mm (H) so that the thickness is 40 mm, and this is a roller firing kiln which is a continuous firing furnace. In an atmosphere having an oxygen concentration of 85% by volume, the temperature of the atmosphere is increased from 500 ° C. to 780 ° C. at a constant rate for 7.5 hours and held at 780 ° C. for 7 hours. Went. At this time, the retention time in the temperature range of 550 ° C. or more and 650 ° C. or less of the mixture itself measured by inserting a thermocouple into the mixture is 110 minutes, and the maximum reached temperature of the measured sintered product is 780 ° C. The retention time was 7 hours. Further, the time required for the mixture to enter and exit from the baking furnace (time from the start of baking to the completion of cooling) was 20 hours. In addition, the temperature of the baked product when leaving the baking furnace was 110 to 140 ° C.

  The obtained fired product was put into pure water so as to have a mass ratio of 1.5 with respect to water 1 to make a slurry, stirred for 30 minutes, filtered and dried to obtain a positive electrode active material.

  Next, using the obtained positive electrode active material, a secondary battery as shown in FIG. 1 was produced by the following method.

First, 5% by mass of acetylene black and 5% by mass of polyvinylidene fluoride (PVDF) were mixed with 90% by mass of the active material powder, and N-methyl-2-pyrrolidone (NMP) was added to the resulting mixture to make a paste. This was applied to a 20 μm thick aluminum foil so that the mass of the active material after drying was 0.05 g / cm ² , vacuum-dried at 120 ° C., and then punched into a disk shape having a diameter of 1 cm to obtain a positive electrode. .

Further, lithium metal was applied as the negative electrode, and an equivalent mixed solution of ethylene carbonate (EC) and diethyl carbonate (DEC) using 1 mol / L LiClO ₄ as a supporting salt was used as the electrolyte. Then, a 2032 type coin battery as shown in FIG. 1 was produced in a glove box in an argon atmosphere in which a separator made of polyethylene was impregnated with an electrolytic solution and the dew point was controlled at −80 ° C.

The produced secondary battery is left for about 24 hours, and after the open circuit voltage (OCV) is stabilized, the current density with respect to the positive electrode is 0.5 mA / cm ² and the charge / discharge test is performed at a cutoff voltage of 4.3 to 3.0 V. The first discharge capacity was measured.

The holding time (T1) in the temperature range of 550 ° C. or more and 650 ° C. or less and the first discharge capacity of the mixture are determined by the formula: time (min) = 0.026 t ² −2.7 Minimum holding time (T2) Table 1 also shows.

(Example 2)
A positive electrode active material was obtained in the same manner as in Example 1 except that the thickness of the mixture charged in the firing container was changed to 45 mm, and the obtained battery was evaluated. Table 1 shows the holding time (T1) and the first discharge capacity in the temperature range of 550 ° C. or more and 650 ° C. or less, together with the minimum holding time (T2).

(Example 3)
A positive electrode active material was obtained in the same manner as in Example 1 except that the thickness of the mixture charged in the firing container was 50 mm, and the obtained battery was evaluated. Table 1 shows the holding time (T1) and the first discharge capacity in the temperature range of 550 ° C. or more and 650 ° C. or less, together with the minimum holding time (T2).

Example 4
A positive electrode active material was obtained in the same manner as in Example 1 except that the thickness of the mixture charged in the baking container was changed to 55 mm, and the obtained battery was evaluated. Table 1 shows the holding time (T1) of the mixture at 550 ° C. or more and 650 ° C. or less and the first discharge capacity together with the minimum holding time (T2).

(Example 5)
A positive electrode active material was obtained in the same manner as in Example 1 except that the thickness of the mixture charged in the firing container was changed to 60 mm, and the obtained battery was evaluated. Table 1 shows the holding time (T1) of the mixture at 550 ° C. or more and 650 ° C. or less and the first discharge capacity together with the minimum holding time (T2).

(Example 6)
The thickness of the mixture charged in the baking container was 40 mm, the temperature of the atmosphere was increased from 600 ° C. to 780 ° C. over 9 hours at a constant rate, and held at 780 ° C. for 4 hours. Except for the above, a positive electrode active material was obtained in the same manner as in Example 1, and the obtained battery was evaluated. The retention time of the actually measured mixture in the temperature range of 550 ° C. to 650 ° C. was 60 minutes, and the maximum reached temperature and the retention time of the actually measured mixture were 4 hours at 780 ° C. The time required for the mixture to enter and exit from the firing furnace was 18.5 hours. Table 1 shows the holding time (T1) and the first discharge capacity in the temperature range of 550 ° C. or more and 650 ° C. or less, together with the minimum holding time (T2).

(Example 7)
A positive electrode active material was obtained in the same manner as in Example 6 except that the thickness of the mixture charged in the firing container was 45 mm, and the obtained battery was evaluated. Table 1 shows the holding time (T1) of the mixture at 550 ° C. or more and 650 ° C. or less and the first discharge capacity together with the minimum holding time (T2).

(Comparative Example 1)
A positive electrode active material was obtained in the same manner as in Example 6 except that the thickness of the mixture charged in the firing container was set to 50 mm, and the obtained battery was evaluated. Table 1 shows the holding time (T1) of the mixture at 550 ° C. or more and 650 ° C. or less and the first discharge capacity together with the minimum holding time (T2).

(Comparative Example 2)
A positive electrode active material was obtained in the same manner as in Example 6 except that the thickness of the mixture charged in the baking container was 55 mm, and the obtained battery was evaluated. Table 1 shows the holding time (T1) of the mixture at 550 ° C. or more and 650 ° C. or less and the first discharge capacity together with the minimum holding time (T2).

(Comparative Example 3)
A positive electrode active material was obtained in the same manner as in Example 6 except that the thickness of the mixture charged in the baking container was 60 mm, and the obtained battery was evaluated. Table 1 shows the holding time (T1) of the mixture at 550 ° C. or more and 650 ° C. or less and the first discharge capacity together with the minimum holding time (T2).

(Example 8)
The thickness of the mixture charged in the firing container was 40 mm, the atmosphere was heated from 600 ° C. to 780 ° C. at a constant rate over 4 hours, and kept at 780 ° C. for 10 hours. Except for the above, the positive electrode active material was obtained in the same manner as in Example 1, and the obtained battery was evaluated. The retention time in the temperature range of 550 ° C. to 650 ° C. of the actually measured mixture was 60 minutes, and the maximum reached temperature and the retention time of the actually measured mixture were 10 hours at 780 ° C. The time required for the mixture to enter and exit from the firing furnace was 19.5 hours. Table 1 shows the holding time (T1) and the first discharge capacity in the temperature range of 550 ° C. or more and 650 ° C. or less, together with the minimum holding time (T2).

(Comparative Example 4)
A positive electrode active material was obtained in the same manner as in Example 8 except that the thickness of the mixture charged in the baking container was changed to 45 mm, and the obtained battery was evaluated. Table 1 shows the holding time (T1) of the mixture at 550 ° C. or more and 650 ° C. or less and the first discharge capacity together with the minimum holding time (T2).

(Comparative Example 5)
A positive electrode active material was obtained in the same manner as in Example 8 except that the thickness of the mixture charged in the firing container was changed to 50 mm, and the obtained battery was evaluated. Table 1 shows the holding time (T1) of the mixture at 550 ° C. or more and 650 ° C. or less and the first discharge capacity together with the minimum holding time (T2).

(Comparative Example 6)
A positive electrode active material was obtained in the same manner as in Example 8, except that the thickness of the mixture charged in the firing container was 55 mm, and the obtained battery was evaluated. Table 1 shows the holding time (T1) of the mixture at 550 ° C. or more and 650 ° C. or less and the first discharge capacity together with the minimum holding time (T2).

(Comparative Example 7)
A positive electrode active material was obtained in the same manner as in Example 8 except that the thickness of the mixture charged in the firing container was changed to 60 mm, and the obtained battery was evaluated. Table 1 shows the holding time (T1) of the mixture at 550 ° C. or more and 650 ° C. or less and the first discharge capacity together with the minimum holding time (T2).

（評価）
１）５５０℃〜６５０℃の保持時間が同じであれば混合物の厚さが小さいほど、混合物の厚さが同じであれば５５０℃〜６５０℃の保持時間が長いほど、電池の１回目の放電容量は高い傾向がある。

(Evaluation)
1) When the holding time of 550 ° C. to 650 ° C. is the same, the smaller the thickness of the mixture, and the same the thickness of the mixture, the longer the holding time of 550 ° C. to 650 ° C., the first discharge of the battery Capacity tends to be high.

  2) When the fabricated secondary batteries according to the examples and comparative examples were evaluated, the first discharge capacity of the batteries of these examples was generally better than the comparative examples, both of which were 198 mAh / g. The above high discharge capacity is shown.

Example 9
While changing the thickness (t) of the mixture charged in the baking container at 40 to 60 mm and adjusting the temperature increase rate from 500 ° C. to 780 ° C., the holding time in the temperature range of 550 ° C. to 650 ° C. A positive electrode active material was obtained and the obtained battery was evaluated in the same manner as in Example 1 except that was changed. When the first discharge capacity is 198 mAh / g or more, it is evaluated as good (◯), and when the discharge capacity is less than 198 mAh / g, it is evaluated as poor (x). The holding time (minute) in the temperature range of 650 ° C. or lower is taken, and the obtained results are shown in FIG. When the relationship between the thickness t (mm) of the mixture having a capacity of 198 mAh / g or more and the holding time T1 (min) in the temperature range of 550 ° C. to 650 ° C. is estimated from FIG. 2, the minimum holding time (T2 ; Min) = 0.026 t ² -2.7.

If the holding time is 0.030 t ² (min) or more, the first discharge capacity tends to exceed 200 mAh / g. If the holding time is 0.040 t ² (min) or more, the first discharge capacity is A tendency to exceed 202 mAh / g was observed.

  In order to take advantage of the non-aqueous electrolyte secondary battery of the present invention that always has a high initial discharge capacity of 198 mAh / g or more while being excellent in mass productivity, small portable electronic devices that always require high capacity Use as a power source for equipment is preferred.

  In addition, in order for lithium-ion secondary batteries to become popular as power sources for electric vehicles, it is essential to reduce the cost of the batteries, but it is possible to reduce the cost by using the positive electrode active material of the present invention that is excellent in mass productivity. Therefore, it can be said that its industrial value is extremely large. The power source for electric vehicles includes not only a purely electric vehicle driven by electric energy but also a so-called hybrid vehicle power source used in combination with a combustion engine such as a gasoline engine or a diesel engine.

DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Negative electrode 3 Separator 4 Gasket 5 Positive electrode can 6 Negative electrode can B Coin battery

Claims (10)

A method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery comprising a lithium nickel composite oxide, obtained by mixing a nickel composite compound having an average particle size of 8 to 20 μm and a lithium compound In the step of filling a mixture with a bulk density of 1.0 to 2.2 g / ml into a firing container and firing, the thickness when the mixture is placed in the firing container is t (mm). The time during which the temperature of the mixture is maintained in the temperature range of 550 ° C. or higher and 650 ° C. or lower is set to be equal to or longer than the minimum holding time determined by the formula: time (minutes) = 0.026 t ² −2.7, and the oxygen concentration is 60 A method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery, wherein the mixture is fired in an oxidizing atmosphere having a capacity of at least% and the resulting fired product is washed with water.   The method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein the mixture is maintained in the temperature region in an atmosphere having an oxygen concentration of 80% by volume or more.   3. The non-aqueous electrolyte secondary according to claim 1, wherein in the firing step, the maximum temperature reached by the mixture is 650 ° C. or more and 800 ° C. or less, and the holding time at the maximum temperature is 4 hours or more. A method for producing a positive electrode active material for a battery.   The method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein in the firing step, the time from the start of heating of the mixture to the completion of cooling is 24 hours or less.   The method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein the lithium compound is lithium hydroxide or lithium hydroxide hydrate.   The manufacturing method of the positive electrode active material for nonaqueous electrolyte secondary batteries in any one of Claims 1-5 whose said nickel complex compound is nickel complex oxide or nickel complex hydroxide. The composition of the lithium nickel composite oxide has a general formula: Li _x Ni _(1-yz) Co _y M _z O ₂ (wherein M represents at least one element selected from Al and Ti). , X, y, and z satisfy 0.90 ≦ x ≦ 1.10, 0.05 ≦ y ≦ 0.35, and 0.005 ≦ z ≦ 0.15, respectively. 6. A method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery according to any one of 6 above.   A positive electrode active material for a non-aqueous electrolyte secondary battery obtained by the production method according to claim 1.   The non-aqueous electrolyte according to claim 8, wherein when used as a positive electrode material of a non-aqueous electrolyte secondary battery comprising a 2032 type coin battery, the first discharge capacity of the non-aqueous electrolyte secondary battery is 198 mAh / g or more. Positive electrode active material for secondary battery.   A non-aqueous electrolyte secondary battery using the positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 8 as a positive electrode material.

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