JP2004200160A - Positive electrode material for lithium secondary battery, its manufacturing method, and lithium secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive electrode material for a lithium secondary battery which has high safety and a large capacity, which is superior in rate characteristics, and superior in charge and discharge efficiency. <P>SOLUTION: This positive electrode material is that in which Al is further added to Li-Ni-Co-Ba-O series raw material, and further preferably that in which oxide amorphous phase is added. This is a compound oxide in which the total composition is expressed by Li<SB>a</SB>Ni<SB>b</SB>Co<SB>c</SB>Ba<SB>d</SB>Al<SB>e</SB>O<SB>x</SB>or Li<SB>a</SB>Ni<SB>b</SB>Co<SB>c</SB>Ba<SB>d</SB>Al<SB>e</SB>M<SB>f</SB>O<SB>x</SB>, and M: is an element of one kind or more selected among a group composed of Na, K, Si, B and P, and a: is 1.0-1.2 mol, b: 0.5-0.95 mol, c: 0.05-0.5 mol, d: 0.0005-0.01 mol, e: 0.01-0.1 mol, and f: 0.01 mol or less (not containing O). <P>COPYRIGHT: (C)2004,JPO&NCIPI

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 method for producing the same, and a lithium secondary battery using the novel material.

  In recent years, the lithium secondary battery positive electrode material has been improved in various ways, and has a Li-Ni-Co-O-based or Li-Ni-Co-Ba-O-based composition as a high-capacity secondary battery positive electrode material. There are materials.

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

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

Further, a positive electrode active material comprising a compound represented by formula _{Li 1-Xa A X Ni 1} -Yb B Y O 2, and positive electrode active material average particle diameter of 0.01μm or more, below 5.0μm There is a positive electrode active material that forms secondary particles that are aggregates of certain primary particles and has an average particle diameter of 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, see Patent Document 2).

  When these materials are used for a positive electrode for a lithium secondary battery, the cycle characteristics of the secondary battery are excellent, but heat stability, capacity, rate characteristics, charge / discharge efficiency, and high-temperature storage characteristics are mentioned. Absent.

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

  The present inventors have conducted further intensive studies on the improvement of the characteristics of the positive electrode material for a lithium secondary battery, and as a result, have developed a material having more excellent characteristics.

  The present invention provides a novel cathode 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 to 0.95
c / (b + c): 0.05-0.5
d / (b + c): 0.0005 to 0.01
e / (b + c): 0.01 to 0.1
b + c = 1
x: Not specified.

  By mixing 0.01 to 0.1 mol of Al with the Li-Ni-Co-Ba-O-based composite oxide, the lithium ion diffusion rate inside or on the surface of the positive electrode material during charge / discharge is improved so that a large current can be obtained. The effect of preventing the capacity from being reduced even when the battery is operating in the above is recognized. Therefore, an improvement in output characteristics required for a lithium secondary battery for an automobile or the like can be expected. Further, since the crystal state in the charged state is improved, deterioration of the capacity is prevented even in a high temperature environment.

  Further, when the oxide amorphous phase is dispersed in the composite oxide particles, the permeability of the electrolytic solution is good, which is effective in improving the discharge capacity and the charge / discharge efficiency. Further, by preventing collapse of the positive electrode material even during expansion and contraction due to charge and discharge, cycle characteristics can be improved. Further, it is effective in preventing gelation and improving the electrode density in the electrode manufacturing process.

  When the constituent components of the oxide amorphous phase are oxides of one or more elements selected from the group consisting of Li, Ba, and Al, the oxide amorphous phase is easily formed. This is 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. Here, 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 to 0.95
c / (b + c): 0.05-0.5
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 positive electrode material for a lithium secondary battery described above can be manufactured by the following method of the present invention.
(A) Ba and Al raw materials are added to a Li-Ni-Co-O-based raw material and fired.
(B) The raw material of (a) is further mixed with a component for forming an oxide amorphous phase and fired. Thus, a positive electrode material for a lithium secondary battery in which an oxide amorphous phase is dispersed inside powder particles can be manufactured.
(C) After firing in the step (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 in which an oxide amorphous phase is dispersed on the surface of powder particles can be produced.
(D) After firing in the step (b), a component for forming an oxide amorphous phase is further mixed and fired again to obtain lithium in which the oxide amorphous phase is dispersed inside and on the surface of the powder particles. A positive electrode material for a secondary battery can be manufactured.

  The present invention provides a lithium secondary battery including a positive electrode composed of any of the above positive electrode materials for a lithium secondary battery.

  According to the present invention, it is possible to obtain 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.

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 particles (C) An oxide amorphous phase is formed on the surface of the particles (D A) A positive electrode material for a lithium secondary battery, wherein an amorphous oxide phase is formed inside and on the surface of the particles.

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

  In addition, although the effect of the oxide amorphous phase is not necessarily clear, the permeability of the electrolytic solution is improved, which is effective in improving the discharge capacity. Further, even when the Li—Ni—Co—Ba—Al—O-based composite oxide crystal expands and contracts due to charge and discharge, the collapse of the positive electrode material is prevented, so that the cycle characteristics can be improved. Further, 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 contained in the 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 forming the oxide amorphous phase include Na, K, Si, B and P included in the definition of M, and further include, for example, Ca, Mg, Zn, Ti, Sr, and Zr. , S, Fe, Ge, As, W, Mo, Te, F and the like. Other elements may be combined with the oxide amorphous phase containing one or more elements selected from the group consisting of Li to Al.

  The reason for limiting the numerical values will be described below.

  The present invention is an improvement on a conventionally known positive electrode material powder for a lithium secondary battery mainly composed of a 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 total of Ni and Co is 1 mole (that is, b + c = 1) is shown.

  Li is 1.0 to 1.2 mol. When the amount of Li is small, the crystal structure has many lithium deficiencies, and the capacity is reduced. If the amount is too large, lithium hydroxide, lithium carbonate or the like is generated, and it becomes difficult to manufacture an electrode.

  Co enhances the thermal stability, but if it is too large, it reduces the discharge capacity.

  Ba is contained in an amount of 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. When the amount is less than 0.01 mol, the effect of diffusion of Li ions is small, and when the amount is more than 0.1 mol, the capacity of the battery is reduced. Therefore, the amount is limited to 0.01 to 0.1 mol.

  The total amount of the oxide amorphous phase forming element added as necessary is 0.01 mol or less. Addition of more than 0.01 mol mainly causes a decrease in the discharge capacity.

  As a raw material used for manufacturing the composite oxide of Li-Ni-Co-Ba-Al, an oxide or an oxide which can be formed by a firing reaction at the time of synthesis in a manufacturing process can be used.

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

Oxides, hydroxides, nitrates, and the like can be used as the Ni source and the Co source, and uniform mixing of Ni and Co is important. For example, Ni-Co- (OH) by a wet synthesis method is used. 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, 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 Ni-Co- (OH) ₂ is reflected in the shape of the Li-Ni-Co-Ba-Al composite oxide after the firing reaction. Further, a material in which components such as Li, Na, K, Si, Ba, B, P, and Al are contained in Ni—Co— (OH) ₂ can also be used.

  As the Ba source, a hydroxide, a nitrate or the like is preferable, and as the Al source, an oxide, a hydroxide, a nitrate or the like is preferable.

  Further, the present invention further comprises mixing a component for forming an oxide amorphous phase with a Li-Ni-Co-Ba-Al-O-based raw material and firing the mixture, or After firing the -Al-O-based raw material, components for forming an oxide amorphous phase are further mixed and fired again. This makes it possible to produce a positive electrode material for a lithium secondary battery in which an oxide amorphous phase is dispersed in a powder or an oxide amorphous phase is attached to the surface of a powder.

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

  The generated oxide amorphous phase is scattered throughout 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 at least one of Li, Ba, and Al, an oxide or a material that becomes an oxide by firing can be used. Further, the same applies to a raw material for forming an oxide-based amorphous phase composed of one or more of Li, Na, K, Si, Ba, B, P, and Al.

  Li and Ba nitrates have high reactivity during firing, help formation of an amorphous phase, and have strong oxidizing power. Therefore, the main structure of the Li-Ni-Co-Ba-Al-O-based compound is a crystal structure. However, the present invention is not limited to this, since active characteristics can be obtained as a positive electrode material because it does not cause any substantial loss. The same applies to the nitrates of Na and K.

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.

  The oxide-based amorphous phase composed of at least one 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-mentioned raw material which becomes an oxide or an oxide by firing can be used. However, glass is prepared in advance, and crushed glass powder is converted into Li-Ni- It is also possible to add it to a 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. However, 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 can be said for an oxide-based amorphous phase composed of one or more of Li, Na, K, Si, Ba, B, P and Al.

(Example 1)
Three types of Ni—Co— (OH) ₂ adjusted to a molar ratio of Co / (Ni + Co) = 0.1, 0.2, and 0.3 as a Ni source and a Co source, respectively, by a wet synthesis method Produced by As other starting materials, commercially available chemicals were used. Each Li source is LiOH.H ₂ O
Na source is NaNO ₃
The K source is KNO ₃
Ba source is Ba (NO ₃ ) ₂
B source is H ₃ BO ₃
The Al _{source, Al (NO 3) 3 ·} 9H 2 O
The Si source is SiO ₂
P source is 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 have a desired composition, and then mixed well to obtain raw materials for firing. The calcination is performed in an oxygen atmosphere. First, the calcination is carried out at 400 ° C. for 4 hours. After mainly removing the moisture in the raw material, the calcination temperature and time shown in Table 1 are maintained at a rate of 5 ° C./min. The fired product was taken out of the furnace. The fired product taken out was crushed to obtain a positive electrode material powder. The obtained powder was subjected to laser diffraction particle size distribution measurement and chemical analysis. Table 1 also shows the molar ratio of each element corresponding to Ni + Co = 1 from the average particle size obtained by the particle size distribution measurement and the chemical analysis value.

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

(Comparative example)
Except for changing the composition, the types of raw materials and the sintering 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 An initial product was obtained by the raw materials used in 1 and the same firing method. Additives shown in Table 3 were added to the initial product, fired again in an oxygen atmosphere, and crushed to obtain a positive electrode material powder. The average particle size was determined by a laser diffraction method, and the molar ratio of each element was determined by a chemical analysis.

  No. 8-No. No. 11 shows that an oxide amorphous phase was formed on the surface of the particles. 12-No. Reference numeral 13 denotes an oxide amorphous phase formed on the surface and inside of the particles.

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

Next, a method for evaluating battery characteristics will be described below. N-methyl-2-pyrrolidone was added to 90% by mass of the positive electrode material powder for a lithium secondary battery obtained in Examples and Comparative Examples, 5% by mass of acetylene black and 5% by mass of polyvinylidene fluoride, and kneaded sufficiently. Thereafter, a product coated and dried on a 20-μm-thick aluminum current collector was pressed by a roll-type press to a thickness of 80 μm, and a punched one having a diameter of 14 mm was 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 film was used as the separator. As the electrolytic solution, one 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. It was assembled into a test cell in a glove box replaced 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 . Further, the first charge / discharge efficiency was calculated by the following equation.

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

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 measured by charging and discharging between 3.0 and 4.2 V at a constant current density of 5.0 mA / cm ² by assembling the same test cells, measuring up to 100 cycles, and calculating by the following formula. .

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

High-temperature storage characteristics (%) = ｛(discharge capacity value after high-temperature storage)
/ (Discharge capacity value before high temperature storage)｝ × 100
The measuring method of the output characteristics is as follows. N-methyl-2-pyrrolidone was added to 90% by mass of the positive electrode material powder for a lithium secondary battery obtained in Examples and Comparative Examples, 5% by mass of acetylene black and 5% by mass of polyvinylidene fluoride, and kneaded sufficiently. Thereafter, a product coated and dried on an aluminum current collector having a thickness of 20 μm was pressed by a roll-type press so as to have a thickness of 65 μm, and a punched product having a diameter of 10 mm was 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 film was used as the separator. As the electrolytic solution, one 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. It was assembled into a test cell in a glove box replaced with argon. 8 hours at a constant current density of 1.0 mA / cm ^2, after the constant-current constant-voltage charge to 4.25 V, when performing discharge at a constant current density of 1.0 mA / cm ² to 2.5V At a discharge depth of 50% at a current density of 3.0, 6.0, 9.0 mA / cm ² for 10 seconds, the voltage was measured. The open circuit voltage V ₀ and the internal resistance R from the approximate straight line of the current and voltage values at this time was determined and calculated output characteristic W / g active material mass in the positive electrode as m the following equation.

W / g = V ₀ × 2.5 / R / m
Prototypes of the nail test battery were produced as follows.

After mixing 89% by mass of the positive electrode material powder for a lithium secondary battery synthesized in Example 1, 6% by mass of acetylene black and 5% by mass of polyvinylidene fluoride, N-methyl-2-pyrrolidone was added and kneaded sufficiently. This was applied to an aluminum current collector having a thickness of 20 μm, dried and pressed to produce a positive electrode. The negative electrode was prepared by adding N-methyl-2-pyrrolidone to 92% by mass of carbon black, 3% by mass of acetylene black and 5% by mass of polyvinylidene fluoride, kneading the mixture sufficiently, and applying the mixture to a 14 μm thick copper current collector. It was made by drying and pressing. The thicknesses of the positive electrode and the negative electrode were 75 μm and 100 μm, respectively. The electrolytic solution was prepared 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. The separator was a porous polypropylene film and an aluminum laminate. A prismatic battery having a size of 60 mm × 35 mm × thickness of 4 mm was prototyped. The battery was charged up to 4.2 V at a current value of 160 mA, and the discharge capacity was measured up to 3.0 V at the same current value. As a result, it was 780 mAh.

  Example No. In the same manner as in 4, 9, 11, and 13 and Comparative Examples 2, 5, and 6, batteries were produced using the positive electrode material powder for a lithium secondary battery synthesized under each condition.

  In the nailing test, the battery was charged at a constant current of 4.2 mA at a constant current of 4.2 mA for 8 hours at a constant voltage of 8 mA, and then a nail having a diameter of 2.5 mm was passed through the center of the battery at a speed of 15 mm / sec. The state of the battery at this time was observed. If there was no smoking, ignition, or rupture, the test was accepted. If smoke, ignition, etc. was recognized, 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 to 0.95
c / (b + c): 0.05-0.5
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 and formed inside the composite oxide powder particles. The positive electrode material for a lithium secondary battery according to claim 1, wherein an oxide amorphous phase is formed on surfaces of the composite oxide powder particles. The oxide amorphous phase is dispersed and formed inside the powder particles of the composite oxide, and the oxide amorphous phase is formed on the surface of the particles. Positive electrode material for lithium secondary batteries. The constituent component of the oxide amorphous phase is an oxide of one or two or more elements selected from the group consisting of Li, Ba, and Al. 4. The positive electrode material for a lithium secondary battery according to 1. Total composition _{Li a Ni b Co c Ba d} Al e M f O positive electrode material for a lithium secondary battery which is a composite oxide represented by _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 to 0.95
c / (b + c): 0.05-0.5
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. 7. The positive electrode material for a lithium secondary battery according to claim 6, wherein the composite oxide is a powder, and an oxide amorphous phase is dispersed and formed inside the powder particles. 7. The positive electrode material for a lithium secondary battery according to claim 6, wherein the composite oxide is a powder, and an oxide amorphous phase is formed on the surface of the powder particles. The composite oxide is a powder, and the oxide amorphous phase is dispersed and formed inside the powder particles, and the oxide amorphous phase is formed on the surface of the powder particles. The positive electrode material for a lithium secondary battery according to claim 6, wherein: A method for producing a positive electrode material for a lithium secondary battery, comprising adding a Ba material and an Al material to a Li-Ni-Co-O-based material and calcining the material. A cathode material for a lithium secondary battery, characterized by mixing and firing one or more of Na, K, Si, B and P materials in addition to Ba and Al materials to a Li-Ni-Co-O-based material. Production method. A method for producing a positive electrode material for a lithium secondary battery, comprising adding a Ba raw material, an Al raw material, and a raw material for forming an oxide amorphous phase to a Li-Ni-Co-O raw material and firing the resultant. A cathode material for a lithium secondary battery, characterized in that, after adding Ba and Al raw materials to a Li-Ni-Co-O raw material and firing, a raw material for forming an oxide amorphous phase is further mixed and fired again. Manufacturing method. After adding a Ba raw material, an Al raw material and a raw material for forming an oxide amorphous phase to a 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 lithium secondary battery, comprising: A lithium secondary battery comprising a positive electrode made of the positive electrode material for a lithium secondary battery according to claim 1.