JP2003300734A - Method for manufacturing lithium transition metal compound oxide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a lithium transition metal compound oxide which can suppress a degradation in cell characteristics such as charge-discharge cycle characteristics due to expansion and shrinkage of the lithium transition metal compound oxide. <P>SOLUTION: In the process of manufacturing the lithium transition metal compound oxide by calcining a lithium compound and a transition metal compound, calcinations is carried out in the presence of a metal chalcogenide having a higher melting point than the calcination temperature and/or a metal chalcogenide to be converted into a conductive compound by the calcination. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a lithium composite oxide preferably used as a positive electrode active material of a lithium secondary battery and a method for producing the same.

[0002]

2. Description of the Related Art Lithium composite oxides are regarded as promising as a positive electrode active material that can provide a practically usable lithium secondary battery. Among these lithium composite oxides, a composite oxide of lithium and a transition metal, particularly cobalt, nickel, and manganese as transition metals, lithium cobalt-based oxide, lithium nickel-based oxide, and lithium manganese-based oxide are used as a positive electrode active material. It is also known that when used as a material, high performance battery characteristics can be obtained.

The lithium-transition metal composite oxide in the present invention means a composite oxide containing at least lithium and a transition metal. As a method for producing a lithium-transition metal composite oxide, it is general to calcination a lithium compound as a raw material, a transition metal compound, and other raw material compounds used as necessary at a high temperature. By such a method, it is possible to obtain a lithium transition metal composite oxide powder in which a plurality of primary particles are usually aggregated to form secondary particles.

On the other hand, when the lithium-transition metal composite oxide is used as an active material for a lithium secondary battery or the like, the lithium-transition metal composite oxide usually has a low electron conductivity, and therefore, a conductive agent is used to prepare a positive electrode sheet. As such, graphite, acetylene black, etc. are used. Specifically, an active material composed of a lithium transition metal composite oxide and a conductive agent such as graphite or acetylene black are suspended in a suitable solvent together with a binder, and the suspension is applied onto a current collector, A positive electrode of a lithium ion secondary battery is manufactured by drying and forming a thin plate.

[0005]

In the active material of the lithium ion secondary battery as described above, lithium ions are taken in and out during charge / discharge operation, and as a result, the crystal lattice thereof repeatedly expands and contracts. . As a result, the conventional electrode using a carbon-based conductive agent such as graphite or acetylene black has a problem that the conductive agent is separated from the active material as the active material contracts and expands. Separation of the conductive agent from the active material causes a decrease in conductivity, which causes the discharge capacity of the lithium ion secondary battery to deteriorate over time. Further, the separation of the conductive agent causes the active material to come into direct contact with the electrolytic solution, which deteriorates the characteristics of the active material itself over time. Therefore, in a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery, it is strongly desired to suppress deterioration of charge / discharge cycle characteristics due to separation of a conductive agent.

In particular, the contact state (aggregated state) between primary particles due to the expansion and contraction of the lithium-transition metal composite oxide active material.
Is changed, the problem is particularly large because there are no conductive particles between the primary particles. In order to solve such a problem, in Japanese Unexamined Patent Publication No. 2001-328813,
Disclosed is a lithium-manganese composite oxide in which primary particles having a carbon material as conductive particles attached to the surface are aggregated to form secondary particles. According to the description in the above publication, when such a lithium manganese composite oxide is used, the conductivity inside the secondary particles is increased, and as a result, the internal resistance is decreased, and the secondary particles are formed by repeating charging and discharging. It is said that the conductivity inside the secondary particles can be maintained high even when a gap is formed inside the particles.

[0007] However, in the above publication, in order to produce such particles, the precursor of the lithium manganese composite oxide is treated by a low temperature treatment such as a hydrothermal method. Such a manufacturing method is often not sufficient in terms of productivity when considering production on an industrial scale. The present invention has been made to address such a problem, and it is possible to suppress deterioration of battery characteristics such as charge / discharge cycle characteristics due to expansion and contraction of the lithium transition metal composite oxide. An object of the present invention is to provide a non-aqueous electrolyte secondary battery with improved battery characteristics such as charge / discharge cycle characteristics by using such a lithium-transition metal composite oxide. Is intended.

[0008]

Means for Solving the Problems As a result of intensive investigations by the present inventors in order to achieve the above object, as a result of the presence of a specific compound when firing a lithium compound and a transition metal compound, secondary particles It has been found that high cycle characteristics can be obtained if conductive particles are present even inside, and the present invention has been completed.

That is, the gist of the present invention is as follows (1) to (1)
It exists in 1). (1) In the method for producing a lithium-transition metal composite oxide by firing a lithium compound and a transition metal compound, the firing is performed by a conductive metal chalcogenide having a melting point higher than the temperature at the firing and / or the firing. A method for producing a lithium-transition metal composite oxide, which is carried out in the presence of a conductive compound precursor (hereinafter, may be collectively simply referred to as "raw material additive") that produces a conductive compound. (2) The method for producing a lithium-transition metal composite oxide according to (1), wherein the firing temperature is 500 ° C. or higher. (3) The metal chalcogenide and at least one selected from the group consisting of a lithium compound, a transition metal compound, and a reaction product of a lithium compound and a transition metal compound are wet-mixed in advance before firing (1). Alternatively, the method for producing the lithium-transition metal composite oxide according to any one of (2). (4) The method for producing a lithium-transition metal composite oxide according to (3), wherein the mixture is wet-mixed and then subjected to spray drying treatment. (5) The method for producing a lithium-transition metal composite oxide according to (3) or (4), wherein a sol-like metal chalcogenide used during wet mixing is used. (6) The method for producing a lithium-transition metal composite oxide according to any one of (1) to (5) above, wherein the metal chalcogenide contains an oxide containing antimony. (7) Lithium transition metal composite oxide powder in which a plurality of primary particles are aggregated to form secondary particles, and lithium transition metal in which conductive antimony-containing chalcogenide particles are present between the primary particles Complex oxide powder. (8) The lithium-transition metal composite oxide powder according to (7) above, wherein the conductive metal chalcogenide particles contain an oxide containing antimony. (9) A positive electrode for a lithium secondary battery, which is formed by forming a positive electrode layer containing the lithium transition metal composite oxide powder according to (7) or (8) and a binder on a current collector. (10) A lithium secondary battery using the lithium-transition metal composite oxide powder according to (7) or (8) as a positive electrode active material.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below. (1) Method for producing lithium-transition metal composite oxide The lithium-transition metal composite oxide is obtained by firing a lithium compound as a raw material, a transition metal compound, and a compound containing other elements used as necessary. It can be manufactured. (1-1) Raw material Examples of the lithium compound as a raw material include, for example, lithium oxides, hydroxides, oxyhydroxides, inorganic acid salts such as carbonates, nitrates and sulfates, and organic salts such as acetates. Mention may be made of halides such as acid salts and chlorides, and hydrates thereof. Among them, preferably, lithium hydroxide, lithium hydroxide monohydrate, lithium carbonate, lithium nitrate, organic acid salts of lithium and lithium oxide,
More preferably, lithium hydroxide, lithium hydroxide monohydrate, lithium carbonate, lithium nitrate and lithium acetate can be mentioned. Most preferably, it is lithium hydroxide monohydrate. A plurality of lithium compounds may be used in combination.

Examples of the metal element in the transition metal compound as a raw material include cobalt, manganese, nickel,
Various transition metal elements such as iron, chromium, vanadium, titanium, copper, niobium, tantalum and zirconium can be mentioned. These plural types can be used in combination. Among these, cobalt, manganese, and nickel are preferable in terms of battery performance such as capacity. Compounds of these transition metal elements include oxides, hydroxides and oxyhydroxides of the above metals, inorganic acid salts such as carbonates, nitrates and sulfates, organic acid salts such as acetates, chlorides and the like. Mention may be made of halides.

When a manganese compound is used as an example of the transition metal compound, a specific manganese compound is
For example, manganese oxides such as MnO ₂ , Mn ₂ O ₃ , Mn ₃ O ₄ , and MnO, hydroxides of manganese, inorganic acid salts of manganese such as manganese carbonate, manganese nitrate, and manganese sulfate, M
Examples thereof include oxyhydroxide of manganese such as nOOH and organic acid salts of manganese such as manganese acetate. Organic acid salts of manganese oxide, manganese hydroxide, manganese oxyhydroxide, manganese nitrate, manganese sulfate and manganese are preferred, and MnO ₂ and Mn ₂ are more preferred.
O ₃ and Mn ₃ O ₄ . A plurality of these manganese compounds may be used in combination.

When a nickel compound is used as an example of the transition metal compound, specific nickel compounds include, for example, nickel oxides such as NiO, Ni ₂ O ₃ and Ni ₃ O ₄ , and nickel hydroxide. Examples thereof include inorganic acid salts of nickel such as nickel carbonate, nickel nitrate, nickel sulfate, and nickel chloride, Ni oxyhydroxide such as NiOOH, and organic acid salts of nickel such as nickel acetate. Preferably, nickel oxide, nickel hydroxide,
Organic acid salts of nickel oxyhydroxide, nickel nitrate, nickel sulfate and nickel, more preferably nickel hydroxide, NiO, Ni ₂ O ₃ and Ni ₃ O ₄ . A plurality of these nickel compounds may be used in combination.

Furthermore, as an example of the transition metal compound,
When a cobalt compound is used, specific cobalt compounds include, for example, cobalt oxides such as CoO, Co ₂ O ₃ and Co ₃ O ₄ , cobalt hydroxide, cobalt carbonate,
Inorganic acid salt of cobalt such as cobalt nitrate and cobalt sulfate,
Examples thereof include Co oxyhydroxide such as CoOOH and ovalt organic acid salt such as cobalt acetate. Organic salts of cobalt oxide, cobalt hydroxide, cobalt oxyhydroxide, cobalt nitrate, cobalt sulfate and cobalt are preferable, and CoO and Co are more preferable.
₂ O ₃ and Co ₃ O ₄ . A plurality of these cobalt compounds may be used in combination.

In one of the preferred embodiments, as the transition metal compound, at least two compounds selected from manganese compounds, nickel compounds and cobalt compounds are used in combination. As a result, battery characteristics such as cycle characteristics can be further improved. If necessary, a compound containing an element other than lithium and a transition metal can be contained as a raw material. For example, for substituting a part of nickel sites in the lithium nickel composite oxide, Al,
Ga, Bi, Sn, Zn, Mg, Ge, Be, B, C
A compound containing an element such as a or Sc can be used. Of these elements, Al, Zn and M are preferable.
g, B, and Ca, and more preferably,
Al, Mg, Ca can be mentioned. Most preferably, Al can be mentioned. Specifically, oxides, hydroxides, oxyhydroxides of the above elements, inorganic acid salts such as nitrates and sulfates excluding carbonates, organic acid salts such as acetates, halides such as chlorides, and These hydrates can be mentioned. A compound containing an element other than the nickel compound may be contained in combination of plural kinds.

For example, in the case of producing a lithium nickel composite oxide, in order to replace a part of nickel sites of the lithium nickel composite oxide with a transition metal element other than nickel or an element other than the above transition metal, the above elements are contained. It is preferable to use the compound as a raw material. Particularly preferably, a compound of at least one element selected from the group consisting of cobalt, aluminum and manganese is used as a raw material together with a lithium compound and a nickel compound.

The composition ratio of the raw material components is appropriately selected according to the composition of the desired lithium composite oxide. For example,
When synthesizing a lithium manganese composite oxide having a layered structure, the Li / Mn molar ratio is usually about 0.8 to 1.2,
It is preferably 0.9 to 1.2. In addition, when synthesizing a lithium manganese oxide having a spinel structure, Li /
The Mn molar ratio is usually about 0.4 to 0.6, preferably 0.45 to 0.55. (1-2) Raw Material Additive In the present invention, firing is performed in the presence of the raw material additive. The raw material additive to be used is one having a melting point higher than the temperature at the time of firing, and / or one which produces a conductive compound as a result of firing. As a result, the conductive particles remain in a state of maintaining conductivity by firing, or conductive particles are generated as a result of firing, and the inside of the secondary particles of the lithium-transition metal composite oxide (between the primary particles It is possible to allow the conductive particles to be present in (1). When a metal chalcogenide having a melting point higher than the firing temperature is used, the melting point of the conductive metal chalcogenide varies depending on the firing temperature, but is usually 500 ° C. or higher, preferably 550 ° C. or higher, and more preferably The temperature is 600 ° C. or higher, most preferably 650 ° C. or higher. The higher the melting point, the smaller the change at the time of firing, which is preferable. However, since it is practically difficult to obtain a material having an excessively high melting point, the measurable numerical value of the melting point is 1500 ° C. or less.

The conductive compound precursor that produces a conductive compound as a result of firing can be appropriately selected depending on the firing conditions and the kind of the target conductive compound. As such a conductive compound precursor, for example,
There are various metal oxides and sulfides,
Oxides are preferably used. The type of metal element is not particularly limited, but antimony or tin can be exemplified. Specific examples thereof include Sb ₂ O ₅ and SnO ₂ . Of course, some of these metal elements can be replaced with other elements. Preference is given to antimony-containing chalcogenides such as Sb ₂ O ₅ and antimony-doped SnO ₂ , especially oxides.

The property of the raw material additive is not particularly limited, but as described later, in order to make the raw material additive and the raw material of the lithium-transition metal composite oxide exist in a uniform state, they are previously prepared before firing. Since it is preferable to mix these in a wet manner, it is particularly preferable that the raw material additive is a sol so that it can be easily diffused in the wet medium. Such sols can include ZnO · Sb ₂ O5 sol, Sb ₂ O ₅ sol, antimony-doped SnO ₂ sol.

The smaller the particle diameter of the raw material additive is, the more preferable it is. However, since it is difficult to obtain particles that are too small, it is usually 0.001 to 1 μm, preferably 0.001 μm.
5 to 0.5 μm, more preferably 0.01 to 0.1 μm
m, and most preferably 0.01 to 0.05 μm. The amount of the raw material additive present is usually 0.1% by weight or more, preferably 0.2% by weight or more, more preferably 0.3% by weight or more, with respect to the lithium-transition metal composite oxide produced. It is usually 10% by weight or less, preferably 7.0% by weight or less, and more preferably 5.0% by weight or less. If the amount present is too large, the amount of lithium transition metal composite oxide decreases relatively, and the discharge capacity tends to decrease due to an increase in the inactive part of the battery in the electrode. The characteristics may not be improved sufficiently. (1-3) Mixing Conditions In firing, it is preferable that the raw material lithium compound, transition metal compound, raw material additive, and the like are mixed as uniformly as possible. In this respect, it is preferable to mix them in advance in a liquid medium (wet) before firing. In this case, the raw material additive may be mixed with either or both of the lithium compound and the transition metal compound,
Further, it may be in a state in which these react to form a precursor. In one of the preferable embodiments, the raw material additive and at least the transition metal compound are wet mixed. As a result, it is possible to obtain a lithium-transition metal composite oxide with improved battery performance such as cycle characteristics.

As the solvent (liquid medium) in the wet mixing, various organic solvents and inorganic solvents can be used, but water is used from the viewpoint that the effect of the present invention is remarkably exhibited and industrial advantage. Preference is given to using. Components such as a lithium compound and a transition metal compound that are present in the solvent may be dissolved or dispersed in the solvent, but normally, there are components that are not dissolved to form a slurry property.

The slurry concentration in the slurry varies depending on the kind of the raw material compound, but is usually 0.1 to 60% by weight, preferably 0.1 to 50% by weight, and most preferably 5 to 40% by weight. . If the slurry concentration is too low, the productivity tends to decrease, while if it is too high, it becomes difficult to ensure the uniformity of the slurry composition. In a preferred embodiment of the present invention, as described above, the raw material additive and at least a part of the raw material compound are wet-mixed, and a sol-like raw material additive is used. as a result,
The raw material additive can be dispersed more uniformly. In this case, the addition amount of the sol is, in the case of using an oxide containing antimony, usually 0.
It is about 1 to 10% by weight, preferably about 0.3 to 5% by weight. If the amount of antimony added is too small, the charge / discharge cycle characteristics may not be sufficiently improved. On the other hand, when the amount of antimony added is too large, the mass of the lithium-transition metal composite oxide is relatively reduced, and the inactive portion of the battery in the electrode is increased, so that the discharge capacity tends to be reduced.

The stirring means in the wet mixing is not particularly limited, and examples of the type of agitator include simple motor agitation such as planetary mixer, three-axis planetary mixer, twin-screw butterfly mixer, concentric twin-screw mixer, dissolver, Use of a homomixer, a kneader, etc. is considered. When preparing the slurry, it is more preferable to grind the solid content in the slurry at the same time as stirring, that is, to perform wet grinding from the viewpoint that the effect of the present invention is remarkable and the battery performance. As the stirrer for that purpose, it is preferable to use a stirrer capable of performing strong stirring accompanied by crushing of the solid content in the slurry, for example, a medium stirring type wet fine crusher. The medium agitation type wet pulverizer is generally called a bead mill and is a wet pulverizer that uses beads of glass, ceramics, steel or the like as a pulverizing medium. 70 to 90% of beads as a grinding medium is filled in a vessel, agitator disk and pin are rotated at a peripheral speed of 5 to 15 m / sec to give motion to the beads, and a slurry (material to be crushed) is pumped therein. It is a device that finely pulverizes and disperses by sending in and shearing force between beads. Therefore, the properties required for beads include high fracture strength, abrasion resistance, content of components, stability, etc., and when selecting beads, consider the contamination with slurry, corrosiveness, etc. Need to choose.

Grinding conditions vary depending on the kind of the target lithium-transition metal composite oxide, etc., but in order for the oxide to have a desired secondary particle diameter, the solid particles in the slurry after wet grinding should be The average particle size is preferably as small as possible, usually 2 μm or less, preferably 1 μm or less, and more preferably 0.5 μm or less, and the pulverization conditions can be selected accordingly. However, it is difficult to obtain solid particles having a too small particle diameter after the wet pulverization, so that the particle diameter is usually 0.01 μm or more, preferably 0.05 μm or more, and more preferably 0.1 μm or more.

The crushing treatment does not necessarily have to be carried out in the presence of the raw material additive, and it may be added after the wet crushing treatment. The viscosity of the slurry in the present invention is usually
It is 1 to 10,000 mPa · s. If the viscosity of the slurry is too low, the storage stability of the slurry may be poor, and it may be difficult to obtain clean granulated particles during the production of the lithium transition metal composite oxide. On the other hand, if the viscosity of the slurry is too high, smooth transfer does not proceed, which causes problems in handling, and problems such as difficulty in obtaining fine particles during drying may occur. The viscosity of the slurry is 1 to 5000 mPa
s is preferable, more preferably 1 to 1800 mPa · s, and especially 1
More preferably, it is 100 to 1000 mPa · s.

The viscosity of the slurry can be measured using a known BM type viscometer. BM type viscometer
This is a measurement method that employs a method of rotating a predetermined metal rotor in the room temperature atmosphere. The viscosity of the slurry is calculated from the resistance force (twisting force) applied to the rotating shaft of the rotor when the rotor is rotated while being immersed in the slurry. However, the room temperature atmosphere means an environment in which the temperature is 10 ° C. to 35 ° C. and the relative humidity is 20% RH to 80% RH.

The wet mixed raw materials are usually dried to remove the solvent during firing. The drying method is not particularly limited, but spray drying is preferable from the viewpoint of productivity and control of particle shape. By spray drying, a spherical lithium-transition metal composite oxide can be obtained by a simple method, and as a result, the packing density can be improved. The method of spray drying is not particularly limited, but for example, a droplet of the slurry component from the nozzle by causing a gas flow and a slurry to flow into the tip of the nozzle (this may be simply referred to as “droplet” in this specification). Can be used to rapidly dry the scattered droplets by using an appropriate drying gas temperature and air flow rate. As the gas to be supplied as a gas flow, in addition to air (including CO ₂ -free air), an inert gas such as nitrogen can be used, but air is usually used. It is preferable to use these under pressure. The gas flow has a gas linear velocity of usually 100 m / s or more, preferably 200 m / s or more, and more preferably 300 m / s.
It is injected by the above. If it is too small, it becomes difficult to form appropriate droplets. However, since it is difficult to obtain a too high linear velocity, the normal injection velocity is 1000 m / s or less. The nozzle used may have any shape as long as it can eject minute liquid droplets, and a conventionally known one, for example, liquid droplets described in Japanese Patent No. 2977080 can be miniaturized. Such nozzles can also be used. In addition, it is preferable that the droplets are sprayed in an annular shape from the viewpoint of improving productivity. The scattered droplets are dried. As described above, treatment such as appropriate temperature and air blowing is performed so as to quickly dry the scattered droplets, but it is preferable to introduce the drying gas from the upper part of the drying tower to the lower part by downflow. With such a structure, the throughput per unit volume of the drying tower can be greatly improved. Further, when the liquid droplets are sprayed in a substantially horizontal direction, by suppressing the liquid droplets sprayed in the horizontal direction with downflow gas,
It is possible to greatly reduce the diameter of the drying tower, and it is possible to manufacture at low cost and in large quantities. The drying gas temperature is usually 50 ° C. or higher, preferably 70 ° C. or higher, usually 300 ° C. or lower, preferably 200 ° C. or lower, more preferably 120 ° C. or lower, most preferably 100 ° C. or lower. If the temperature is too high, the resulting granulated particles will have many hollow structures, and the packing density of the powder will tend to decrease, while if it is too low, the powder will stick to the powder due to water condensation at the powder outlet. Problems such as blockages may occur.

By drying, it is possible to obtain granulated particles as a firing raw material. The average particle size of the granulated particles (secondary particle size) is preferably 50 μm or less, more preferably 30 μm or less, from the viewpoint of battery performance. However, since it tends to be difficult to obtain a too small particle size, the particle size is usually 0.1 μm or more, preferably 1 μm or more, more preferably 4 μm or more, and most preferably 5 μm or more. The particle size of the granulated particles can be controlled, for example, by appropriately selecting the spray type, the pressurized gas flow supply rate, the slurry supply rate, the drying temperature and the like in the case of spray drying.

The dried particles are, if necessary, mixed with other compounds and then subjected to a baking treatment. For example, when the slurry does not contain a lithium compound or a compound having a metal element other than lithium, after mixing the slurry with a lithium compound or a compound having a metal element other than lithium, the slurry is subjected to a firing treatment. You can Further, when a part of the lithium compound and / or the compound having a metal element other than lithium is contained in the slurry, the remaining lithium compound and / or the compound having a metal element other than lithium is mixed after the slurry is dried. After that, it can be subjected to a firing treatment. (1-4) Baking treatment The baking temperature during the baking treatment is usually 500 ° C or higher, preferably 550 ° C or higher, more preferably 600 ° C or higher, most preferably 650 ° C or higher, and usually 1000 ° C or lower, preferably It is 900 ° C or lower. If the firing temperature is too low, a long reaction time is required to obtain a lithium-transition metal composite oxide having good crystallinity, and the effect of improving the packing density may be reduced. If the firing temperature is too high,
A phase other than the target lithium-transition metal composite oxide may be generated, or a lithium-transition metal composite oxide with many defects may be generated. When the temperature is raised from room temperature to the above reaction temperature, in order to carry out the reaction more uniformly, the temperature is gradually raised, for example, at a temperature of 5 ° C. or less per minute, or the temperature is temporarily stopped on the way. A holding time at a constant temperature may be added.

The firing time is usually 1 hour or more and 100 hours or less, preferably 2 hours or more and 50 hours or less. If the firing time is too short, it is difficult to obtain a lithium-transition metal composite oxide having good crystallinity, and a reaction time that is too long is not practical. The calcination can be usually performed in the air or an oxygen gas atmosphere, but depending on the case, an inert gas atmosphere selected from nitrogen, argon, helium, or the like, or a mixed gas atmosphere of these gases and an oxygen-containing gas is also performed. be able to.

In order to obtain a lithium-transition metal composite oxide having few crystal defects, it is preferable to slowly cool to a certain temperature after the above firing, and 800 ° C., preferably up to 600 ° C., 5 ° C./min. It is preferable to gradually cool at the following cooling rate. The heating device used for firing is not particularly limited as long as it can achieve the above temperature and atmosphere, and for example, a box furnace, a tubular furnace, a tunnel furnace, a rotary kiln or the like can be used. (2) Lithium-transition metal composite oxide In the lithium-transition metal composite oxide of the present invention, primary particles having conductive particles attached to the surface are aggregated to form secondary particles. In other words, in the lithium-transition metal composite oxide powder of the present invention, a plurality of primary particles are aggregated to form secondary particles, and particles having conductivity are present between the primary particles.

The size of the primary particles depends on the degree of pulverization of the raw material,
It can be controlled by the firing temperature, firing time, etc., and the particle size of the secondary particles can be controlled by the pulverization conditions of the raw materials, the spray drying conditions, the pulverization after firing, the classification conditions, etc. Is. The primary particle diameter of the lithium-transition metal composite oxide is usually 0.1 to 10 μm, preferably 0.1.
1 to 5 μm, and the secondary particle diameter is usually 1 to 100.
μm, preferably 1 to 50 μm. The specific surface area of the lithium-transition metal composite oxide due to nitrogen adsorption is 0.1
It is preferably about 5 m ² / g.

The composition of the lithium-transition metal composite oxide is usually represented by the following general formula (1) except for the conductive metal chalcogenide particles.

[0034]

Embedded image Li _x M ¹ _1-y M ² _y O _2-δ (1) Here, M ¹ represents a transition metal element, and M ² represents an element other than lithium and a transition metal. x represents a number of 0.1 to 1.3, preferably 0.1 to 1.1, and y represents a number of 0 to 0.5, preferably 0.02 to 0.3. δ corresponds to an oxygen deficiency or an oxygen excess amount, and represents a number of −0.1 to 0.1, preferably −0.05 to 0.05. Transition metal element M
¹ is usually cobalt, manganese, nickel, iron, chromium, vanadium, titanium, copper, niobium, tantalum, zirconium, and preferably cobalt, manganese, nickel. In addition, element M other than lithium and transition metal
² is usually Al, Ga, Bi, Sn, Zn, Mg, G
e, Be, B, Ca, Sc, preferably Al, Z
n, Mg, B and Ca, more preferably Al and M
g and Ca, and most preferably Al. Element M ¹
Each of M ² and M ² may be composed of a plurality of elements.

As the crystal structure of the compound represented by the above general formula (1), various structures such as spinel structure and layered structure can be adopted. The conductive particles in the secondary particles may be the metal chalcogenide itself used at the time of production, or may be those produced by firing. The type of conductive particles is not particularly limited as long as it can impart appropriate conductivity to the lithium-transition metal composite oxide, but as the metal chalcogenide used during production, use antimony or tin chalcogenide. Is preferred,
The conductive particles present in the secondary particles also preferably contain antimony or tin. Among them, antimony-containing chalcogenides, particularly antimony-containing oxides are preferable. In the firing system, there are some raw materials for lithium-transition metal composite oxides such as lithium and transition metals, so that the conductive particles may also contain the elements constituting the raw material compounds. For example, the oxide of antimony as the conductive metal chalcogenide used in the preferred embodiment of the present invention has a composition of LiCoSbO ₄ , where the cobalt element and the lithium element are the raw materials of the lithium-transition metal composite oxide, respectively. May be derived from.

The electric conductivity of the conductive particles is usually 10 ⁵ S /
The value is not particularly limited as long as it is m or more, but has a higher electric conductivity than the lithium-transition metal composite oxide itself and can impart appropriate conductivity to the lithium-transition metal composite oxide. The particle size of the conductive particles in the lithium transition metal composite oxide powder is usually 0.1 μm or less, preferably 0.05 μm or less, and more preferably 0.02 μm.
m or less. The smaller the particle size, the more preferable in terms of battery performance such as cycle characteristics. However, since it is practically difficult to obtain particles having a too small particle diameter, the particle diameter is usually 0.005 μm or more, preferably 0.01 μm or more.

In the lithium-transition metal composite oxide powder of the present invention, a plurality of primary particles are aggregated to form secondary particles, and conductive particles are present between the primary particles. Therefore,
Even when the lithium-transition metal composite oxide contracts or expands with charge / discharge operation, the conductive particles as a conductive agent do not separate, and therefore the conductivity of the positive electrode is stabilized against the progress of charge / discharge cycles. It can be maintained and has excellent battery characteristics such as battery capacity, rate characteristics, cycle characteristics, storage characteristics, and safety. (3) Lithium Secondary Battery A lithium secondary battery can be prepared by using the lithium transition metal composite oxide of the present invention as a positive electrode active material.

The lithium secondary battery usually has a positive electrode, a negative electrode and an electrolyte layer. As an example of a lithium secondary battery,
A secondary battery including a positive electrode, a negative electrode, an electrolytic solution, and a separator can be mentioned. In this case, an electrolyte exists between the positive electrode and the negative electrode, and the separator is arranged between them so that the positive electrode and the negative electrode do not come into contact with each other. The positive electrode contains the lithium-transition metal composite oxide and a binder. Also usually
The positive electrode is formed by forming a positive electrode layer containing the positive electrode material and a binder on a current collector.

Such a positive electrode layer can be manufactured by applying a slurry of a lithium transition metal composite oxide, a binder and, if necessary, a conductive agent and the like in a solvent to a positive electrode current collector and drying. it can. In the positive electrode layer, Li
An active material capable of inserting and extracting lithium ions other than the lithium-transition metal composite oxide, such as FePO _4, may be further contained.

The proportion of the active material in the positive electrode layer is usually 10% by weight or more, preferably 30% by weight or more, more preferably 50% by weight or more, usually 99.9% by weight or less, preferably 99% by weight or less. Is. If it is too large, the mechanical strength of the electrode tends to be poor, and if it is too small, the battery performance such as capacity tends to be poor. Examples of the binder used for the positive electrode include polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, EP
DM (ethylene-propylene-diene terpolymer), S
Examples thereof include BR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), fluororubber, polyvinyl acetate, polymethylmethacrylate, polyethylene and nitrocellulose. The proportion of the binder in the positive electrode layer is usually 0.1% by weight or more, preferably 1% by weight or more, more preferably 5% by weight or more, and usually 80% by weight or less, preferably 60% by weight or less, more preferably It is 40% by weight or less, and most preferably 10% by weight or less. When the proportion of the binder is too low, the active material cannot be sufficiently retained and the mechanical strength of the positive electrode is insufficient, which may deteriorate the battery performance such as cycle characteristics. On the other hand, when it is too high, the battery capacity and conductivity may be reduced. May be lowered.

The positive electrode layer usually contains a conductive agent in order to enhance conductivity. Examples of the conductive agent include graphite such as natural graphite and artificial graphite, carbon black such as acetylene black, and carbon material such as amorphous carbon such as needle coke. The proportion of the conductive agent also in the positive electrode is usually 0.01% by weight or more, preferably 0.1% by weight or more, more preferably 1% by weight or more, usually 50% by weight or less, preferably 30% by weight or less, It is preferably 15% by weight or less. If the proportion of the conductive agent is too low, the conductivity may be insufficient, and conversely, if it is too high, the battery capacity may decrease.

The slurry solvent is not particularly limited as long as it dissolves or disperses the binder, but an organic solvent is usually used. For example, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N, N
-Dimethylaminopropylamine, ethylene oxide,
Tetrahydrofuran etc. can be mentioned. It is also possible to add a dispersant, a thickener and the like to water to make the active material into a slurry with a latex such as SBR.

The thickness of the positive electrode layer is usually 1 to 1000 μm,
It is preferably about 10 to 200 μm. If it is too thick, the conductivity tends to decrease, and if it is too thin, the capacity tends to decrease. As the material of the current collector used for the positive electrode, aluminum, stainless steel, nickel-plated steel or the like is used, and aluminum is preferable. The thickness of the current collector is usually 1 to 1000 μm, preferably 5 to 500 μm
It is a degree. If it is too thick, the capacity of the lithium secondary battery as a whole may be reduced, and if it is too thin, the mechanical strength may be insufficient.

The positive electrode layer obtained by coating and drying is preferably compacted by a roller press or the like in order to increase the packing density of the active material. The negative electrode active material used for the negative electrode of the secondary battery may be lithium or a lithium alloy such as a lithium aluminum alloy, but a carbon material having higher safety and capable of absorbing and releasing lithium is preferable.

The carbon material is not particularly limited, but graphite, coal-based coke, petroleum-based coke, coal-based pitch carbide, petroleum-based pitch carbide, or carbide obtained by subjecting these pitches to oxidation treatment, needle coke, pitch coke, Examples thereof include phenol resins, carbides such as crystalline cellulose and the like, and carbon materials obtained by partially graphitizing these, furnace black, acetylene black, pitch carbon fibers and the like.

Further, as the negative electrode active material, SnO, SnO
2, Sn1-xMxO (M = Hg, P, B, Si, Ge or Sb, where 0≤x <1), Sn3O2 (OH) 2, Sn3
-xMxO2 (M = Mg, P, B, Si, Ge, Sb or M
n, where 0 ≦ x <3), LiSiO2, SiO2, Li
SnO2 etc. can be mentioned. A mixture of two or more selected from these may be used as the negative electrode active material.

The negative electrode is usually formed by forming a negative electrode layer on a current collector as in the case of the positive electrode. The binder used at this time, and the conductive agent and the like used as necessary and the slurry solvent may be the same as those used for the positive electrode. Further, as the current collector of the negative electrode, copper, nickel, stainless steel, nickel-plated steel or the like is used, and preferably copper is used.

When a separator is used between the positive electrode and the negative electrode, a microporous polymer film is usually used, and polytetrafluoroethylene, polyester, nylon,
Those composed of polyolefin polymers such as cellulose acetate, nitrocellulose, polysulfone, polyacrylonitrile, polyvinylidene fluoride, polypropylene, polyethylene and polybutene are used. Further, a non-woven filter of glass fiber or the like, or a non-woven filter of glass fiber and polymer fiber can also be used. The chemical and electrochemical stability of the separator is an important factor.
From this point of view, the polyolefin-based polymer is preferable, and from the viewpoint of the self-closing temperature which is one of the purposes of the battery separator, it is preferable to be made of polyethylene.

In the case of the polyethylene separator, ultrahigh molecular weight polyethylene is preferable from the viewpoint of shape retention at high temperature, and the lower limit of its molecular weight is preferably 500,000, more preferably 1,000,000, and most preferably 1.5 million. On the other hand, the upper limit of the molecular weight is preferably 5,000,000, more preferably 4,000,000, and most preferably 3,000,000. If the molecular weight is too small, the clogging property becomes too high, which causes a problem in use at high temperature. If the molecular weight is too large, the fluidity may be too low to block the pores of the separator when heated.

As the electrolyte forming the electrolyte layer in the lithium secondary battery, for example, known organic electrolytes, polymer solid electrolytes, gel electrolytes, inorganic solid electrolytes and the like can be used. Is preferred. The organic electrolytic solution is composed of an organic solvent and a solute. The organic solvent is not particularly limited, for example, carbonates, ethers, ketones, sulfolane compounds,
Lactones, nitriles, chlorinated hydrocarbons, ethers, amines, esters, amides, phosphoric acid ester compounds and the like can be used. When these representative ones are specifically listed, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate, tetrahydrofuran, 2-methyl tetrahydrofuran, 1,4-dioxane, 4- Methyl-2-pentanone, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methylsulfolane, acetonitrile , Propionitrile, benzonitrile, butyronitrile, valeronitrile, 1,2-dichloroethane, dimethylformamide, dimethylsulfoxide, trimethyl phosphate, triethyl phosphate, etc. Rukoto is possible, these alone or two or more kinds of mixed solvents can be used.

The above-mentioned organic solvent preferably contains a high dielectric constant solvent for dissociating the electrolyte. Here, the high dielectric constant solvent has a relative dielectric constant of 20 at 25 ° C.
The above compounds are meant. In the high dielectric constant solvent, it is preferable that the electrolytic solution contains ethylene carbonate, propylene carbonate, γ-butyrolactone, and a compound in which the hydrogen atom thereof is replaced with another element such as halogen or an alkyl group. The ratio of the high dielectric constant compound in the electrolytic solution is preferably 20% by weight or more, more preferably 30% by weight.
It is at least 40% by weight, most preferably at least 40% by weight. This is because if the content of the compound is small, desired battery characteristics may not be obtained.

The solute to be dissolved in this solvent is not particularly limited, but any conventionally known solute can be used, such as LiClO ₄ , LiAsF ₆ , LiPF ₆ and Li.
BF ₄ , LiB (C ₆ H ₅ ) ₄ , LiCl, LiBr, CH
₃ SO ₃ Li, CF ₃ SO ₃ Li, LiN (SO ₂ CF ₃ ) ₂ ,
Examples thereof include LiN (SO ₂ C ₂ F ₅ ) ₂ and LiC (SO ₂ CF ₃ ) _{3, and} at least one of them can be used. Further, an additive such as a gas such as CO ₂ , N ₂ O, CO, SO ₂ or the like, such as polysulfide Sx2-, which forms a good film capable of efficiently charging and discharging lithium ions on the surface of the negative electrode, is used alone in any ratio. Alternatively, it may be added to the mixed solvent.

When the polymer solid electrolyte is used, the known polymer can be used. In particular, it is preferable to use a polymer having high ionic conductivity with respect to lithium ions, and for example, polyethylene oxide, polypropylene oxide, polyethyleneimine and the like are preferably used. It is also possible to add the above solvent to the polymer together with the above solute and use it as a gel electrolyte.

When an inorganic solid electrolyte is used, a known crystalline or amorphous solid electrolyte can be used for this inorganic substance. Examples of the crystalline solid electrolyte include Li
I, Li ₃ N, Li _{1 + x} M _x Ti _2-x (PO ₄ ) ₃ (M
= At least one selected from the group consisting of Al, Sc, Y and La), Li _0.5-3x RE _{0.5 + x} TiO ₃ (provided that R is
E = La, Pr, at least one) and the like are selected from the group consisting of Nd and Sm, as the solid electrolyte of the amorphous _{example, 4.9LiI-34.1Li 2 O-61B} 2 O 5, 3
Oxide glass such as 3.3Li ₂ O-66.7SiO ₂ or 0.45Li
_{I-0.37Li 2 S-0.26B 2} S 3, 0.30LiI-0.42Li 2
Examples thereof include sulfide glass such as S-0.28SiS ₂ . At least one of these can be used.

[0055]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In addition, the viscosity of the slurry in the examples was measured by a BM type viscometer (manufactured by Tokimec). The measurement is performed in a room temperature atmosphere, a specific metal rotor is fixed to the rotary shaft of the apparatus main body, the rotor is immersed in a slurry liquid, the rotor is rotated, and the scale after 3 minutes is read, using a conversion table, The slurry viscosity was calculated from the rotor and rotation speed. <Example _{1> (1) Li 1.05 Ni} 0.82 Co 0.15 Al 0.03 O 2 manufacturing _{LiOH · H 2 O, NiO,} Co (OH) 2 and AlOO
H is the composition in each of the final rock salt structure type lithium nickel composite oxides, and Li: Ni: Co: Al = 1.
It was weighed so as to be 05: 0.82: 0.15: 0.03 (molar ratio), and pure water was added to this to prepare a slurry having a solid content concentration of 30% by weight. While stirring this slurry, a circulation type medium stirring type wet pulverizer (manufactured by Shinmaru Enterprises Co., Ltd .: Dyno-mill KDL-A type) was used.
The slurry was pulverized for 6 hours until the average particle size of the solid content in the slurry became 0.25 μm.

The viscosity of the obtained slurry was measured with a BM type viscometer (manufactured by Tokimec). As a result, the slurry viscosity was 340 mPa · s. Next, the conductive double oxide sol (ZnO.Sb ₂
An amount of O ₅ solid content concentration 30 wt% particle size 20 nm) was measured and added to the slurry in an amount of 3 wt% with respect to the solid content in the slurry, and the solution was uniformly dispersed in the slurry using a dissolver.

Next, the slurry was spray-dried using a two-fluid nozzle type spray dryer (manufactured by Okawara Kakoki Co., Ltd .: LT-8 type spray dryer). Air was used as the dry gas at this time, and the dry gas introduction rate was 50 L / min.
And the inlet temperature of the dry gas was 90 ° C. Then, the granulated particles obtained by spray drying were placed under an oxygen gas atmosphere for 7
By baking at 25 ° C. for 24 hours, a lithium nickel composite oxide having a molar ratio composition almost as charged was obtained.

The particle size of the obtained lithium nickel composite oxide was measured by using a laser diffraction / scattering type particle size distribution measuring device (manufactured by Horiba, Ltd .: LA-910 type particle size distribution measuring device), and an average secondary particle was obtained. The particles had a substantially spherical shape with a diameter of 10.7 μm and a maximum particle diameter of 26 μm. The crystallinity of the obtained lithium nickel composite oxide was measured by a powder X-ray diffractometer (X-ray diffractometer PW3710 manufactured by Philips).
As a result of measurement using a mold, Cu bulb, 40 kV, 30 mA), it was confirmed to have a structure of a lithium nickel composite oxide having a rock salt structure. In addition, LiCo
A diffraction pattern identified by SbO ₄ was also confirmed.

Further, by SEM observation, it was confirmed that a large number of particles adhered to the surfaces of the primary particles constituting the secondary particles, and the conductive particles exist between the primary particles. (2) Preparation of lithium secondary battery The obtained Li _1.05 Ni _0.82 Co _0.15 Al _0.03 O ₂ was used as an active material, and acetylene black as a conductive agent and polytetrafluoroethylene as a binder were used in a weight ratio. 7
After mixing 5: 20: 5, thoroughly kneading in an agate mortar, and forming into a sheet, punching into a diameter of 9 mm for rate characteristic measurement and 12 mm for high temperature cycle characteristic measurement, and then a diameter of 16 mm In the case of 9 mm in diameter, pressure is applied to the Al current collector of 14 MPa under a pressure of 14 MPa, and in case of a diameter of 12 mm is pressed under a pressure of 20 MPa, respectively, at 120 ° C.
After vacuum drying for a period of time, a positive electrode was obtained.

A 2032 type coin battery was assembled with the obtained positive electrode in a glove box in an argon atmosphere. A lithium metal having a diameter of 16 mm and a thickness of 1 mm was used for the negative electrode for measuring the rate characteristic. Also, for the negative electrode for measuring high-temperature cycle characteristics, a copper foil having a thickness of 20 μm has an average particle size of 8 to 10 μm.
Polyvinylidene fluoride was used as a binder and the polyvinyl powder was weighed at a weight ratio of 92.5: 7.5, dispersed in N-methylpyrrolidone, and the coated product was dried and had a diameter of 12 mm. It was punched out and pressed at a pressure of 0.5 ton / cm ² .

At this time, the balance between the weight of the positive electrode active material and the weight of the negative electrode active material is determined by the initial charge capacity of the complex oxide being Qc
(mAh / g), negative electrode capacity is Q (F) mAh / g (negative electrode is test electrode, Li
A coin-type battery with a metal counter electrode was assembled, and Li ions were inserted (lower limit 0 V) and desorbed (upper limit) into the negative electrode at a sufficiently low current amount.
1.5V), the initial insertion capacity at the time of performing the test) was calculated by the following formula (1).

[0062]

[Equation 1] Amount of positive electrode active material [g] / Amount of negative electrode active material [g] = Q (F) /Qc/1.2 Equation (1) Next, the ion cell manufactured according to the above procedure is subjected to current value I (mA). so,
The charging / discharging capacity was measured twice for the upper limit of 4.1 V and the lower limit of 3.0 V, and the initial conditioning was performed. The current value I was calculated by the following formula (2) when the initial discharge capacity of the coin type half cell is Qd1.

[0063]

[Equation 2] Conditioning current value I (mA) = Qd1 * M / 5 (mA) ・ ・ ・ Equation (2) 2nd discharge capacity in ionizing cell 2 conditioning 2nd discharge capacity (= Qd2 * M 3) (see).

The electrolyte solution contained 1 mol / liter of Li.
A mixed solution of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of 3: 7 using PF ₆ as a supporting salt was used. (3) Battery performance evaluation Measurement of Initial Discharge Capacity For the battery manufactured as described above, the rate characteristic measurement condition was 0.2 in a voltage range of 3.2V to 4.2V.
The initial discharge capacity (mAh / g) per unit weight of the positive electrode active material was measured when the charge / discharge test was performed at a current density of mA / cm ² . B. (Chronopotentiometry measurement method) After initial conditioning, fully relax the battery, and
3) C (calculated from the following formula (3)) current value was charged with constant current for 72 minutes, and then left still for 1 hour. Then, after standing still for 1 h or more in a low temperature atmosphere of −30 ° C., discharge was performed for 10 seconds at a current value of 1.5 C (calculated from the following general formula (4)). The difference ΔV between the OCV immediately before discharging and the ultimate voltage 10 seconds after discharging was determined. The results are shown in Table-1. ΔV was as small as 596 mV, showing that more power can be taken out. (Method for determining 1.5C current value) The 1-hour rate current value, that is, 1C, is a current value that can be reached from the lower limit voltage to the upper limit voltage in 1 h when performing constant current charging. According to this definition, the 1 / 3C current value is 1/3 times the 1C current and the 1.5C current value is 1.5 times the 1C current.

When the discharge capacity of the second time in the conditioning of the ion cell is Qd2, it is calculated by the equation (3).

[0066]

## EQU00003 ## 1 C [mA] = Qd2 (mAh / g) * amount of positive electrode active material M (g) ... Formula (3) C.I. (High temperature cycle test method of ion cell) After the initial conditioning, the battery was placed in an atmosphere of 50 ° C, and the constant current charge and the constant current discharge were performed between the upper limit of 4.2V and the lower limit of 3.0V at the 1C current value determined by the formula (4). The battery capacity was measured by repeating 100 times. When the discharge capacity Qmax of the C cycle that takes the maximum discharge capacity is 100%, the discharge capacity Q100th at the 100th cycle is the capacity maintenance rate Z% of the battery.
Was calculated by equation (4). The results are shown in Table-1. The capacity retention rate was as good as 88%.

[0067]

## EQU00004 ## Capacity retention ratio Z (%) = (Q100th / Qmax) * (100 / 100-C) * 100 Formula (4) <Comparative Example 1> The conductive agent used in Example 1 was not added. A lithium transition metal composite oxide and a lithium secondary battery were manufactured and evaluated in the same manner as in Example 1 except for the above. The results are shown in Table-1.

<Example 2> (1) Production of Li _1.05 Ni _0.77 Co _0.20 Al _0.03 O ₂ LiOH.H 2 O, NiO, Co (OH) ₂ and AlOOH raw materials, respectively, final rock salt structure type lithium nickel composite oxidation Li: Ni: Co: Al = 1.0 in the composition
Weighed so as to be 5: 0.77: 0.20: 0.03 (molar ratio), and added pure water to this to obtain a solid content concentration of 30% by weight.
Was prepared. While stirring this slurry,
Using a circulating medium agitation type wet pulverizer (manufactured by Shinmaru Enterprises Co., Ltd .: Dyno Mill KDL-A type), pulverization was performed for 6 hours until the average particle diameter of the solid content in the slurry became 0.25 μm.

At this time, the slurry viscosity was 420 mPa · s.
Met. Next, the conductive double oxide sol (ZnO.Sb ₂ O ₅ solid concentration 30 wt% was added to the slurry prepared as described above.
Particle size 20 nm) 5 w relative to the solid content in the slurry
An amount of t% was weighed, added to the slurry, and uniformly dispersed in the slurry using a dissolver. Next, the slurry was spray-dried using a two-fluid nozzle type spray dryer (LT-8 type spray dryer manufactured by Okawara Kakoki Co., Ltd.). Air was used as the dry gas at this time, the dry gas introduction rate was 50 L / min, and the dry gas inlet temperature was 90 ° C. Then, the granulated particles obtained by spray drying were calcined in an oxygen gas atmosphere at 725 ° C. for 24 hours to obtain a lithium nickel composite oxide having a molar ratio composition almost as charged.

The particle size of the obtained lithium nickel composite oxide was measured by using a laser diffraction / scattering type particle size distribution measuring device (LA-910 type particle size distribution measuring device manufactured by Horiba Ltd.). The particles had a substantially spherical shape with a diameter of 10.7 μm and a maximum particle diameter of 26 μm. The crystallinity of the obtained lithium nickel composite oxide was measured by a powder X-ray diffractometer (X-ray diffractometer PW3710 manufactured by Philips).
As a result of measurement using a mold, Cu bulb, 40 kV, 30 mA), it was confirmed to have a structure of a lithium nickel composite oxide having a rock salt structure. In addition, LiCo
A diffraction pattern identified by SbO ₄ was also confirmed.

Further, by SEM observation, it was confirmed that a large number of particles adhered to the surface of the primary particles constituting the secondary particles, and the conductive particles exist between the primary particles. A coin-type battery was prepared and evaluated in the same manner as described in Example 1. The battery performance evaluation results are shown in Table-1. Comparative Example 2 A lithium transition metal composite oxide and a lithium secondary battery were manufactured and evaluated in the same manner as in Example 2 except that the conductive agent used in Example 2 was not added. The results are shown in Table-1.

[0072]

[Table 1]

[0073]

According to the method of the present invention, a lithium transition metal slurry containing a conductive agent can be obtained. Further, according to the present invention, when a lithium transition metal composite oxide used for a positive electrode of a lithium secondary battery is manufactured by a wet method, a chalcogenide as a conductive agent is added to and mixed with a slurry, which is the same as a conventional method. Through the steps, a lithium-transition metal composite oxide containing a conductive agent can be obtained with high productivity. Also,
The lithium-transition metal composite oxide prepared from the obtained slurry has good battery characteristics and properties. Therefore, the method of the present invention is extremely useful as an industrial production method.

Continued front page    F-term (reference) 4G048 AA04 AB01 AB06 AC06 AD03                       AE05                 5H029 AJ01 AK03 AL02 AL03 AL06                       AL07 AL08 AL12 AM02 AM03                       AM04 AM05 AM07 AM16 CJ02                       CJ08 DJ08 DJ16 EJ04 EJ05                       EJ12 HJ14                 5H050 AA02 AA19 BA16 BA17 CA07                       CA08 CA09 CB02 CB07 CB08                       CB09 CB12 DA10 DA11 EA10                       EA12 EA24 FA17 GA02 GA10                       HA14

Claims (10)

[Claims] 1. A method for producing a lithium-transition metal composite oxide by firing a lithium compound and a transition metal compound, wherein the firing comprises a conductive metal chalcogenide and / or a metal having a melting point higher than the firing temperature. A method for producing a lithium-transition metal composite oxide, which is performed in the presence of a conductive compound precursor that forms a conductive compound by the above-mentioned firing. 2. The firing temperature is 500 ° C. or higher.
The method for producing the lithium-transition metal composite oxide according to 1. 3. A metal chalcogenide and at least one selected from the group consisting of a lithium compound, a transition metal compound, and a reaction product of a lithium compound and a transition metal compound are preliminarily wet-mixed with each other before firing. 1. The method for producing the lithium-transition metal composite oxide according to 1 or 2. 4. The method for producing a lithium-transition metal composite oxide according to claim 3, wherein the mixture is wet-mixed and then subjected to spray drying treatment. 5. The method for producing a lithium-transition metal composite oxide according to claim 3, wherein a sol-like metal chalcogenide used during wet mixing is used. 6. The method for producing a lithium transition metal composite oxide according to claim 1, wherein the metal chalcogenide contains an oxide containing antimony. 7. A lithium-transition metal composite oxide powder comprising a plurality of primary particles aggregated to form secondary particles,
A lithium-transition metal composite oxide powder comprising antimony-containing chalcogenide particles having conductivity between primary particles. 8. The lithium-transition metal composite oxide powder according to claim 7, wherein the conductive metal chalcogenide particles contain an oxide containing antimony. 9. A positive electrode for a lithium secondary battery, wherein a positive electrode layer containing the lithium-transition metal composite oxide powder according to claim 7 or 8 and a binder is formed on a current collector. 10. A lithium secondary battery using the lithium-transition metal composite oxide powder according to claim 7 or 8 as a positive electrode active material.