JP4292064B2 - Positive electrode material for lithium secondary battery, method for producing the same, and lithium secondary battery - Google Patents

Description

  The present invention relates to a positive electrode material for a lithium secondary battery, a method for producing the same, and a lithium battery. More specifically, the positive electrode material for a lithium secondary battery having a Li-Ni-Co-Ba-O-based composition has been improved. The present invention relates to a novel material, a manufacturing method thereof, and a lithium secondary battery using the novel material.

  In recent years, various improvements have been made in the positive electrode material for lithium secondary batteries, and it has a Li-Ni-Co-O-based or Li-Ni-Co-Ba-O-based composition as a positive electrode material for high-capacity secondary batteries. There are materials.

As an example, there is a positive electrode active material that is a compound represented by the chemical formula Li _{1 -Xa} A _X Ni _{1 -Yb} B _Y O ₂ .

However, A: at least two alkaline earth metal elements selected from strontium or barium or magnesium, calcium, strontium and barium B: at least one transition metal element excluding Ni X: total of A Represents the number of moles, 0 <X ≦ 0.10
Y: represents the total number of moles of B, 0 <Y ≦ 0.30
a: −0.10 ≦ a ≦ 0.10
b: −0.15 ≦ b ≦ 0.15
(For example, see Patent Document 1).

The cathode active material is a compound represented by the chemical formula Li _{1 -Xa} A _X Ni _{1 -Yb} B _Y O ₂ , and the cathode active material has an average particle size of 0.01 μm or more and 5.0 μm or less. There is a positive electrode active material that forms secondary particles that are aggregates of certain primary particles, and the average particle size of the secondary particles is 5.0 μm or more and 50 μm or less.

However,
A: Strontium or barium B: At least one transition metal element X: X is the total number of moles of strontium or barium, 0 <X ≦ 0.10
Y: Total number of moles of all transition metal elements other than Ni 0 <Y ≦ 0.30
a: −0.10 ≦ a ≦ 0.10
b: −0.15 ≦ b ≦ 0.15
(For example, refer to Patent Document 2).

  These materials, when used in positive electrodes for lithium secondary batteries, are excellent in cycle characteristics of secondary batteries, but they do not mention thermal stability, capacity, rate characteristics, charge / discharge efficiency, and high-temperature storage characteristics. Absent.

The inventors proceeded with research on a positive electrode material for a lithium secondary battery, further examined the Ba amount with respect to the Li-Ni-Co-Ba-O-based technology, and in a narrow range of Ba content, A material having high thermal stability and a large capacity has been proposed (see, for example, Patent Document 3).
JP-A-9-17430 (page 2-8) JP-A-10-79250 (pages 2-7) Application for Japanese Patent Application No. 2001-173285 (page 3-11)

  As a result of further diligent research on improving the characteristics of the positive electrode material for lithium secondary batteries, the present inventors have developed a material having further excellent characteristics.

  The present invention provides a novel positive electrode material for a lithium secondary battery having high safety, large capacity, and excellent performance in rate characteristics, charge / discharge efficiency, and high-temperature storage characteristics, a method for producing the same, and a lithium secondary battery The purpose is to do.

The present invention is a positive electrode material for a lithium secondary battery, characterized by overall composition is a powder of composite oxide represented by _{Li a Ni b Co c Ba d} Al e O x.
However,
a / (b + c): 1.0 to 1.2
b / (b + c): 0.5-0.95
c / (b + c): 0.05 to 0.5
d / (b + c): 0.0005 to 0.01
e / (b + c): 0.01 to 0.1
b + c = 1
x: Not specified.

  By adding 0.01 to 0.1 mol of Al to the Li—Ni—Co—Ba—O based composite oxide, the Li ion diffusion rate in the positive electrode material or on the surface during charging / discharging is improved, thereby increasing the current. The effect of preventing a decrease in capacity is recognized even during battery operation. For this reason, the improvement of output characteristics required for lithium secondary batteries for automobiles and the like can be expected. Furthermore, since the crystalline state in the charged state becomes good, the deterioration of the capacity is prevented even under a high temperature environment.

  Further, when the oxide amorphous phase is dispersed in the composite oxide particles, the electrolyte has good permeability and is effective in improving the discharge capacity and charge / discharge efficiency. In addition, the cycle characteristics can be improved by preventing the cathode material from collapsing even during expansion / contraction due to charge / discharge. Furthermore, it is effective in preventing gelation and improving electrode density in the electrode manufacturing process.

  The oxide amorphous phase is easily formed when the constituent component of the oxide amorphous phase is an oxide of one or more elements selected from the group consisting of Li, Ba and Al. Can be preferable.

Further, the positive electrode material for a lithium secondary battery of the present invention, for a lithium secondary battery which is a composite oxide entire composition is represented by _{Li a Ni b Co c Ba d} Al e M f O x It is a positive electrode material. Where M: one selected from the group consisting of Na, K, Si, B and P, or
Two or more elements a / (b + c): 1.0 to 1.2
b / (b + c): 0.5-0.95
c / (b + c): 0.05 to 0.5
d / (b + c): 0.0005 to 0.01
e / (b + c): 0.01 to 0.1
f / (b + c): 0.01 or less (excluding 0)
b + c = 1
x: Not specified.

The above positive electrode material for a lithium secondary battery can be manufactured by the following method of the present invention.
(A) a composite oxide overall composition after firing expressed by _{Li a Ni b Co c Ba d} Al e O x
However,
a / (b + c): 1.0 to 1.2
b / (b + c): 0.5-0.95
c / (b + c): 0.05 to 0.5
d / (b + c): 0.0005 to 0.01
e / (b + c): 0.01 to 0.1
b + c = 1
x: Not specified
Then , Ba and Al raw materials are added to the Li—Ni—Co—O-based raw material and fired.
(B) The raw material of (a) is further mixed with a component that forms an oxide amorphous phase and fired. That is, complex oxides overall composition after firing expressed by _{Li a Ni b Co c Ba d} Al e M f O x
However,
M: one selected from the group consisting of Na, K, Si, B and P, or
2 or more elements
a / (b + c): 1.0 to 1.2
b / (b + c): 0.5-0.95
c / (b + c): 0.05 to 0.5
d / (b + c): 0.0005 to 0.01
e / (b + c): 0.01 to 0.1
f / (b + c): 0.01 or less (excluding 0)
b + c = 1
x: Not specified
By mixing one or more of Na, K, Si, B, and P raw materials in addition to Ba and Al raw materials into Li—Ni—Co—O type raw materials and firing , the inside of the powder particles is oxidized. A positive electrode material for a lithium secondary battery in which a physical amorphous phase is dispersed can be produced.
(C) After firing in the above (a), components for forming an oxide amorphous phase are further mixed and fired again. As a result, a positive electrode material for a lithium secondary battery produced by dispersing an oxide amorphous phase on the surface of the powder particles can be produced.
(D) Lithium in which the oxide amorphous phase is dispersed inside and on the surface of the powder particles by further mixing the components that form the oxide amorphous phase after firing in (b) and firing again. A positive electrode material for a secondary battery can be manufactured.

  In addition, this invention provides the lithium secondary battery characterized by including the positive electrode comprised from the positive electrode material for lithium secondary batteries in any one of the above.

  According to the present invention, a positive electrode material for a lithium secondary battery having high safety, large capacity, excellent output characteristics, high-temperature storage characteristics and rate characteristics, and high charge / discharge efficiency can be obtained.

The present invention is a positive electrode material powder for a lithium secondary battery mainly comprising a Li-Ni-Co-Ba-O-based component,
(A) Further containing Al (B) An oxide amorphous phase is contained inside the particle (C) An oxide amorphous phase is formed on the surface of the particle (D ) A positive electrode material for a lithium secondary battery, characterized in that an oxide amorphous phase is formed inside and on the surface of the particle.

  Al is blended in an appropriate amount, so it is considered that there is an effect of improving the diffusion rate of Li ions in Li-Ni-Co-Ba-O-based crystals and preventing crystal collapse under high temperature. By using the material for the positive electrode, it is possible to improve the output characteristics, rate characteristics, storage characteristics at high temperature, and cycle characteristics of the lithium secondary battery.

  Further, although the action of the oxide amorphous phase is not necessarily clear, it improves the discharge capacity because it improves the permeability of the electrolyte. In addition, the cycle characteristics can be improved by preventing the cathode material from collapsing even during the expansion and contraction of the Li—Ni—Co—Ba—Al—O-based composite oxide crystal due to charge / discharge. Furthermore, in the electrode manufacturing process, it is effective in preventing gelation and improving the electrode density.

  Note that elements such as Li, Ba, and Al may be included in a Li—Ni—Co—Ba—Al—O-based crystal or may form an amorphous phase. The same applies to Na, K, Si, B, and P.

  The composition of the oxide amorphous phase is one or more elements selected from the group consisting of Li, Ba and Al. Other elements that form the oxide amorphous phase include Na, K, Si, B, and P included in the definition of M. For example, Ca, Mg, Zn, Ti, Sr, Zr , S, Fe, Ge, As, W, Mo, Te, F, and the like. Other elements may be combined with an oxide amorphous phase containing one or more elements selected from the group consisting of Li to Al.

  The reason for the numerical limitation will be described below.

  The present invention is obtained by improving a positive electrode material powder for a lithium secondary battery mainly composed of a conventionally known Li—Ni—Co—Ba—O-based component.

In the following figures the overall structure of a composite oxide is a positive electrode material for a lithium secondary battery of the present invention _{Li a Ni b Co c Ba d} Al e O x or _{Li a Ni b Co c Ba d} Al e M f When expressed as O _x , the number of moles of each component when the sum of Ni and Co is 1 mole (ie, b + c = 1) is shown.

  Li is 1.0 to 1.2 mol. When there is little Li, it will become a crystal structure with many lithium vacancies, and capacity | capacitance will fall. If the amount is too large, lithium hydroxide, lithium carbonate, and the like are produced, making it difficult to produce the electrode.

  Co increases the thermal stability, but if it is too much, the discharge capacity is reduced, so 0.05 to 0.5 mol.

  Ba contains 0.0005 to 0.01 mol in order to improve thermal stability. Outside this range, it is difficult to obtain appropriate thermal stability.

  Al is 0.01 to 0.1 mol. If the amount is less than 0.01 mol, the effect of Li ion diffusion and the like is small, and if the amount exceeds 0.1 mol, the capacity of the battery is reduced, so the amount is limited to 0.01 to 0.1 mol.

  The total amount of oxide amorphous phase-forming elements added as necessary is 0.01 mol or less. If added in an amount of more than 0.01 mol, the discharge capacity is mainly reduced.

  As a raw material used for manufacturing a composite oxide of Li—Ni—Co—Ba—Al, an oxide or a material that becomes an oxide by a firing reaction during synthesis in a manufacturing process can be used.

  As the Li source, hydroxide, nitrate and the like are preferable.

As the Ni source and the Co source, oxides, hydroxides, nitrates, and the like can be used. Since uniform mixing of Ni and Co is important, for example, Ni—Co— (OH) by a wet synthesis method. ₂ is particularly preferred. The Ni—Co— (OH) ₂ is a secondary particle having a Co / (Ni + Co) molar ratio of 0.05 to 0.5 and an average particle diameter of 5 to 20 μm, and a tap density of 1.8 g / cm. It is preferably ³ or more. The shape of this Ni—Co— (OH) ₂ is reflected in the shape of the Li—Ni—Co—Ba—Al composite oxide after the firing reaction. Moreover, the thing in which components, such as Li, Na, K, Si, Ba, B, P, and Al, were contained in Ni-Co- (OH) ₂ can also be used.

  As the Ba source, hydroxide, nitrate, and the like are preferable, and as the Al source, oxide, hydroxide, nitrate, and the like are preferable.

  In the present invention, the Li-Ni-Co-Ba-Al-O-based raw material is further mixed with a component that forms an oxide amorphous phase and fired, or Li-Ni-Co-Ba -After firing the Al-O-based material, a component for forming an oxide amorphous phase is further mixed and fired again. In this way, it is possible to produce a positive electrode material for a lithium secondary battery in which the oxide amorphous phase is dispersed inside the powder or the oxide amorphous phase adheres to the surface of the powder.

  In addition, the Li-Ni-Co-Ba-Al-O-based raw material is mixed with a component that forms an oxide amorphous phase and baked, and then a component that forms an oxide amorphous phase is further added and then again. When fired, a positive electrode material for a lithium secondary battery in which an oxide amorphous phase is generated inside and on the surface of the particles can be produced.

  The produced oxide amorphous phase is scattered in the particles or the surface of the Li—Ni—Co—Ba—Al—O-based raw material.

  As a raw material for forming an oxide-based amorphous phase composed of one or more of Li, Ba, Al and the like, an oxide or a material that becomes an oxide by firing can be applied. The same applies to the raw material for forming an oxide-based amorphous phase composed of one or more of Li, Na, K, Si, Ba, B, P, and Al.

  Since nitrates of Li and Ba are highly reactive at the time of firing, helping to form an amorphous phase and having strong oxidizing power, the main Li—Ni—Co—Ba—Al—O compound has a crystal structure. However, the present invention is not limited to this. The same applies to the nitrates of Na and K.

As for Al and Si, amorphous fine particles having a BET specific surface area of 100 m ² / g or more are suitable, but not limited thereto.

  Note that the oxide-based amorphous phase composed of one or more of Li, Ba, Al and the like effectively acts on the positive electrode material powder of the present invention. In order to form this oxide-based amorphous phase, the above-described oxide or raw material that becomes an oxide by firing can be used, but glass is prepared in advance and pulverized glass powder is made of Li-Ni-. It is also possible to add to the Co—Ba—Al—O-based raw material.

  The firing temperature is appropriately selected depending on the type of the oxide amorphous phase to be formed, but the firing is performed at 900 ° C. so as not to deteriorate the battery characteristics of the main Li—Ni—Co—Ba—Al—O based composite oxide. The following oxidizing atmosphere is preferable. The same applies to an oxide-based amorphous phase composed of one or more of Li, Na, K, Si, Ba, B, P, and Al.

Example 1
As a raw material Ni source and Co source, three types of Ni—Co— (OH) ₂ adjusted to molar ratios of Co / (Ni + Co) = 0.1, 0.2, and 0.3, respectively, are wet synthesis methods. It was produced by. As other starting materials, commercially available chemicals were used. Each Li source contains LiOH.H ₂ O
NaNO ₃ is used as the Na source.
K source contains KNO ₃
The Ba source includes Ba (NO ₃ ) ₂
B source includes H ₃ BO ₃
The Al source includes Al (NO ₃ ) ₃ · 9H ₂ O
For Si source, SiO ₂
P source includes P ₂ O ₅
Was used. Note that amorphous fine particles were used for SiO ₂ .

  These starting materials were selected, weighed so as to obtain the desired blend composition, and then mixed sufficiently to obtain a raw material for firing. Firing is performed in an oxygen atmosphere, and is first held at 400 ° C. for 4 hours. After mainly removing moisture in the raw material, the firing temperature and time shown in Table 1 are held at a temperature rising rate of 5 ° C./minute, and after cooling The fired product was taken out from the furnace. The taken out fired product was crushed to obtain a positive electrode material powder. The obtained powder was subjected to particle size distribution measurement and chemical analysis by a laser diffraction method. Table 1 shows the molar ratio of each element corresponding to Ni + Co = 1 from the average particle size and the chemical analysis value obtained by the particle size distribution measurement.

  Next, a positive electrode for a lithium secondary battery was manufactured from these, and the battery characteristics were evaluated as described later, and are shown in Table 2.

(Comparative example)
Except for the change in the composition, the types of raw materials and the firing process were the same as in the examples.

  Tables 1 and 2 show the components and battery characteristics as in the examples.

(Example 2)
Example 1 No. The initial product was obtained by the raw material used in 1 and the same firing method. The additive components shown in Table 3 were added to the initial product, fired again in an oxygen atmosphere, and pulverized to obtain a positive electrode material powder. Table 3 shows the average particle diameter determined by laser diffraction and the molar ratio of each element determined by chemical analysis.

  No. 8-No. No. 11 has an oxide amorphous phase formed on the particle surface. 12-No. Reference numeral 13 denotes an oxide amorphous phase formed on the surface and inside of the particle.

  Next, a positive electrode for a lithium secondary battery was produced from these, and the battery characteristics were evaluated as described later.

Next, a method for evaluating battery characteristics is shown below. N-methyl-2-pyrrolidone was added and kneaded sufficiently to 90% by mass of the positive electrode material powder for lithium secondary batteries obtained in Examples and Comparative Examples, 5% by mass of acetylene black and 5% by mass of polyvinylidene fluoride. Thereafter, a 20 μm-thick aluminum current collector applied and dried was pressed with a roll-type press to a thickness of 80 μm, and punched to a diameter of 14 mm, and vacuum-dried at 150 ° C. for 15 hours to obtain a positive electrode. A lithium metal sheet was used as the negative electrode material, and a polypropylene porous membrane was used as the separator. As the electrolytic solution, a solution obtained by dissolving 1 mol of LiPF ₆ in 1 liter of a mixed solution of ethylene carbonate (EC) / dimethyl carbonate (DMC) at a volume ratio of 1: 1 was used. The test cell was assembled in a glove box substituted with argon. The charge capacity and the discharge capacity were determined between 3.0 and 4.2 V at a constant current density of 1.0 mA / cm ² . Furthermore, the first charge / discharge efficiency was calculated by the following formula.

Initial charge / discharge efficiency = (initial discharge capacity) / (initial charge capacity) × 100
In the measurement of the rate characteristic, charge / discharge measurement was further performed at 3.0 to 4.2 V at a constant current density of 5.0 mA / cm ² , and calculation was performed according to the following formula.

Rate characteristic (%) = {(discharge capacity value at 5.0 mA / cm ² )
/ (Discharge capacity value at 1.0 mA / cm ² )} × 100
The cycle characteristics were assembled in the same test cell, measured at a constant current density of 5.0 mA / cm ² between 3.0 and 4.2 V, measured up to 100 cycles, and calculated according to the following formula: .

Cycle characteristics (%) = {(discharge capacity value at 100th cycle)
/ (Discharge capacity value at the first cycle)} × 100
As for the high-temperature storage characteristics, a test cell is assembled in the same manner as the rate characteristics measurement, charge / discharge measurement is performed at a constant current density of 5.0 mA / cm ² between 3.0 and 4.2 V, and discharge before high-temperature storage. After measuring the capacity, the battery is charged for 8 hours to 4.2 V at a constant current density of 5.0 mA / cm ² . After storing the test cell in a charged state in a thermostat adjusted to 60 ° C. for 20 days, the test cell is taken out, cooled naturally to room temperature, and 3 at a constant current density of 5.0 mA / cm ^2. The discharge capacity after high-temperature storage was measured between 0.0 and 4.2 V, and was calculated by the following formula.

High temperature storage characteristics (%) = {(discharge capacity value after high temperature storage)
/ (Discharge capacity value before storage at high temperature)} × 100
The measurement method of output characteristics is as follows. N-methyl-2-pyrrolidone was added and kneaded sufficiently to 90% by mass of the positive electrode material powder for lithium secondary batteries obtained in Examples and Comparative Examples, 5% by mass of acetylene black and 5% by mass of polyvinylidene fluoride. Thereafter, a 20 μm-thick aluminum current collector applied and dried was pressed with a roll-type press to a thickness of 65 μm, and punched to a diameter of 10 mm, and vacuum-dried at 150 ° C. for 15 hours to obtain a positive electrode. A lithium metal sheet was used as the negative electrode material, and a polypropylene porous membrane was used as the separator. As the electrolytic solution, a solution obtained by dissolving 1 mol of LiPF ₆ in 1 liter of a mixed solution of ethylene carbonate (EC) / dimethyl carbonate (DMC) at a volume ratio of 1: 1 was used. The test cell was assembled in a glove box substituted with argon. When charging at a constant current constant voltage of 1.0 mA / cm ² for 8 hours and then charging at a constant current constant voltage of 4.25 V and then discharging to 2.5 V at a constant current density of 1.0 mA / cm ² At a discharge depth of 50%, a voltage was measured when discharging at a current density of 3.0, 6.0, 9.0 mA / cm ² for 10 seconds. The internal resistance R and the open circuit voltage V ₀ were obtained from the approximate straight line of the current value and the voltage value at this time, and the output characteristic W / g was calculated from the following equation, where m is the active material mass in the positive electrode.

W / g = V ₀ × 2.5 / R / m
A battery for nail cutting test was made as follows.

After mixing 89% by mass of the positive electrode material powder for lithium secondary battery synthesized in Example 1, 6% by mass of acetylene black and 5% by mass of polyvinylidene fluoride, adding N-methyl-2-pyrrolidone and kneading sufficiently This was applied to an aluminum current collector with a thickness of 20 μm, dried and pressurized to produce a positive electrode. For the negative electrode, N-methyl-2-pyrrolidone was added to 92% by mass of carbon black, 3% by mass of acetylene black and 5% by mass of polyvinylidene fluoride, kneaded sufficiently, and this was applied to a 14 μm thick copper current collector. It was prepared by drying and pressing. The electrode thicknesses of the positive electrode and the negative electrode were 75 μm and 100 μm, respectively. The electrolyte is a solution in which 1 mol of LiPF ₆ is dissolved in 1 liter of a mixed solution of ethylene carbonate (EC) / dimethyl carbonate (DMC) in a volume ratio of 1: 1. The separator is a polypropylene porous membrane and an aluminum laminate. A square battery having a size of 60 mm × 35 mm × thickness of 4 mm was prototyped. As a result of charging to 4.2 V with a current value of 160 mA and measuring the discharge capacity to 3.0 V with the same current value, it was 780 mAh.

  Example No. 4, 9, 11 and 13 and Comparative Examples 2, 5, and 6 were produced in the same manner as above with respect to positive electrode material powders for lithium secondary batteries synthesized under various conditions.

  In the nail cutting test, the battery was charged at a current of 160 mA at a constant current and a constant voltage of up to 4.2 V for 8 hours, and then a nail having a diameter of 2.5 mm was penetrated through the battery at a speed of 15 mm / sec. The state of the battery at this time was observed. If there was no smoke, fire, or rupture, the test was accepted. If smoke, fire, etc. were observed, the test was rejected.

Claims (15)

Total composition _{Li a Ni b Co c Ba d} Al e O positive electrode material for a lithium secondary battery, which is a powder of composite oxide represented by _x.
However,
a / (b + c): 1.0 to 1.2
b / (b + c): 0.5-0.95
c / (b + c): 0.05 to 0.5
d / (b + c): 0.0005 to 0.01
e / (b + c): 0.01 to 0.1
b + c = 1
x: Not specified.   2. The positive electrode material for a lithium secondary battery according to claim 1, wherein an oxide amorphous phase is dispersed in the powder particles of the composite oxide.   2. The positive electrode material for a lithium secondary battery according to claim 1, wherein an oxide amorphous phase is formed on the surface of the powder particles of the composite oxide.   The oxide amorphous phase is formed in a dispersed state inside the powder particles of the composite oxide, and an oxide amorphous phase is formed on the surface of the particles. Positive electrode material for lithium secondary battery.   The constituent component of the oxide amorphous phase is an oxide of one or more elements selected from the group consisting of Li, Ba and Al. The positive electrode material for lithium secondary batteries as described in 2. A positive electrode material for a lithium secondary battery, wherein the overall composition is _a composite oxide represented by Li _a Ni _b Co _c Ba _d Al _e M _f O _x .
However,
M: one selected from the group consisting of Na, K, Si, B and P, or
Two or more elements a / (b + c): 1.0 to 1.2
b / (b + c): 0.5-0.95
c / (b + c): 0.05 to 0.5
d / (b + c): 0.0005 to 0.01
e / (b + c): 0.01 to 0.1
f / (b + c): 0.01 or less (excluding 0)
b + c = 1
x: Not specified. It said composite oxide is a powder, inside the oxide cathode material for lithium secondary battery according to claim 6, wherein the amorphous phase is characterized by being formed by dispersing the powder particles. It said composite oxide is a powder, the positive electrode material for lithium secondary battery according to claim 6, wherein the oxide amorphous phase on the surface of the powder particles are formed. The composite oxide is a powder, and an oxide amorphous phase is dispersed inside the powder particles, and an oxide amorphous phase is formed on the surface of the powder particles. positive electrode material for lithium secondary battery according to claim 6, wherein. Composite oxides overall composition after firing expressed by _{Li a Ni b Co c Ba d} Al e O x
However,
a / (b + c): 1.0 to 1.2
b / (b + c): 0.5-0.95
c / (b + c): 0.05 to 0.5
d / (b + c): 0.0005 to 0.01
e / (b + c): 0.01 to 0.1
b + c = 1
x: Not specified
The manufacturing method of the positive electrode material for lithium secondary batteries characterized by adding and baking Ba and Al raw material to a Li-Ni-Co-O type raw material. Composite oxides overall composition after firing expressed by _{Li a Ni b Co c Ba d} Al e M f O x
However,
M: one selected from the group consisting of Na, K, Si, B and P, or
2 or more elements
a / (b + c): 1.0 to 1.2
b / (b + c): 0.5-0.95
c / (b + c): 0.05 to 0.5
d / (b + c): 0.0005 to 0.01
e / (b + c): 0.01 to 0.1
f / (b + c): 0.01 or less (excluding 0)
b + c = 1
x: Not specified
As the lithium secondary, characterized in that in addition to Ba and Al raw materials to Li-Ni-Co-O system raw material Na, K, Si, and firing a mixture of one or more B and P raw material A method for producing a positive electrode material for a battery. Composite oxides overall composition after firing expressed by _{Li a Ni b Co c Ba d} Al e O x
However,
a / (b + c): 1.0 to 1.2
b / (b + c): 0.5-0.95
c / (b + c): 0.05 to 0.5
d / (b + c): 0.0005 to 0.01
e / (b + c): 0.01 to 0.1
b + c = 1
x: Not specified
A positive electrode material for a lithium secondary battery, characterized by adding a Ba raw material and an Al raw material to a Li-Ni-Co-O raw material, and further adding a raw material for forming an oxide amorphous phase, followed by firing. Manufacturing method. Composite oxides overall composition after firing expressed by _{Li a Ni b Co c Ba d} Al e O x
However,
a / (b + c): 1.0 to 1.2
b / (b + c): 0.5-0.95
c / (b + c): 0.05 to 0.5
d / (b + c): 0.0005 to 0.01
e / (b + c): 0.01 to 0.1
b + c = 1
x: Not specified
After adding Ba and Al raw materials to the Li—Ni—Co—O raw material and firing, the raw material for forming an oxide amorphous phase is further mixed and fired again. A method for producing a positive electrode material for a secondary battery. Composite oxides overall composition after firing expressed by _{Li a Ni b Co c Ba d} Al e O x
However,
a / (b + c): 1.0 to 1.2
b / (b + c): 0.5-0.95
c / (b + c): 0.05 to 0.5
d / (b + c): 0.0005 to 0.01
e / (b + c): 0.01 to 0.1
b + c = 1
x: Not specified
After adding Ba raw material and Al raw material to the Li—Ni—Co—O raw material, and further adding the raw material for forming the oxide amorphous phase, the oxide amorphous phase is further formed. A method for producing a positive electrode material for a lithium secondary battery, comprising mixing raw materials and firing again.   A lithium secondary battery comprising a positive electrode made of the positive electrode material for a lithium secondary battery according to claim 1.