JP4655453B2 - Positive electrode material for lithium secondary battery, secondary battery using the same, and method for producing positive electrode material for lithium secondary battery - Google Patents

Description

【００８５】
表−１において、実施例１、２と比較例１を比較すると、正極活物質組成の５倍以上、７０倍以下のホウ素またはビスマスが二次粒子表面に濃化して存在している本発明のリチウムニッケルマンガン複合酸化物は、ホウ素とビスマスのいずれも存在しないその他金属配合比が同じリチウムニッケルマンガン複合酸化物よりも、タップ密度が高く、コインセル室温抵抗の６０℃充放電１００サイクル試験前後の変化倍率が低く、よってリチウム二次電池用正極材料として有利であることが判る。実施例３と比較例２を比較すると、同様に実施例３の方がタップ密度が高く、コインセル室温抵抗の６０℃充放電１００サイクル試験前後の変化倍率が低い。マンガン含有量が多い実施例３のような組成では、正極活物質組成の５倍以上、７０倍以下のホウ素またはビスマスを二次粒子表面に濃化させることで、非常に嵩密度が低い比較例３の組成でも高嵩密度を実現できたことが判る。参考例のように、ニッケル含有量が多い組成では、本発明の効果が小さいことが判る。
表−１より、実施例で得られたリチウムニッケルマンガン複合酸化物は粉体タップ密度が高くてかつ比表面積が低く、加えて二次電池としたときの電池性能に優れているものであることが確認された。
【００８６】
【発明の効果】
本発明によれば、リチウム二次電池の正極材料として好適な高性能（高容量、高サイクル特性、高レート特性、高保存特性等）のリチウム二次電池用正極材料を安価に提供することができる。特に、本発明によれば、従来合成されてきたものよりも嵩密度の高いリチウム遷移金属複合酸化物を提供することができる。さらに、本発明によれば、高性能（高充放電効率、低抵抗高出力等）なリチウム二次電池用正極及びリチウム二次電池を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a positive electrode material for a lithium secondary battery comprising a lithium transition metal composite oxide, a method for producing the positive electrode material for a lithium secondary battery, and a secondary battery using the positive electrode material for the lithium secondary battery. .
[0002]
[Prior art]
In recent years, with the reduction in size and weight of portable electronic devices and communication devices, a secondary battery having high output and high energy density is required as a power source. Further, a secondary battery having the above characteristics is also required as a power source for automobiles. In particular, lithium secondary batteries are being developed rapidly to meet the above requirements.
As a positive electrode material for a lithium secondary battery, the standard composition is LiCoO.₂LiNiO₂, LiMn₂O_FourLithium transition metal composite oxides such as these have been used, but various studies have been made to improve battery characteristics.
[0003]
For example, LiCoO₂Patent Document 1 shows that LiCoO has a charge / discharge cycle characteristic by replacing a part of Co with B or Bi.₂Patent Document 2 discloses that charge and discharge cycle characteristics are improved by coating the surfaces of primary particles with boron. LiMO₂When element Z (Bi, B, W) is added to (M is Co, Ni, etc.) so that the atomic ratio (Z / M) is 0.1 or less and fired, element Z is formed at the grain boundaries of the primary particles. Since melting, the size of the primary particles can be increased, and it is disclosed in Patent Document 3 that when this is used as a positive electrode material, the discharge capacity is improved.
[0004]
Meanwhile, among the lithium transition metal composite oxides, LiMn₂O_FourAnd LiNiO₂LiCoO₂Although it is advantageous in that it is less expensive than the above, for practical use, it is necessary to improve the cycle characteristics at high temperature, storage characteristics, atmosphere control during firing and storage, safety aspects, and the like. Therefore, LiNiO₂LiNi in which a part of Ni site of Mn was replaced with Mn_1-xMn_xO₂Is being studied. (For example, Non-Patent Documents 1 to 3) However, when the amount of substitution of Mn is increased, there is a problem that a sufficient capacity cannot be obtained.
[0005]
[Patent Document 1]
JP-A-4-253162
[Patent Document 2]
JP-A-4-328258
[Patent Document 3]
JP-A-8-55624
[Non-Patent Document 1]
J. et al. Mater. Chem. 6 (1996) p. 1149
[Non-Patent Document 2]
J. et al. Electrochem. Soc. 145 (1998) p. 1113
[Non-Patent Document 3]
41st Battery Symposium Proceedings (2000) p. 460
[0006]
[Problems to be solved by the invention]
In recent years, the demand for higher performance of lithium batteries has been increasing, and it has been required to achieve high characteristics such as high capacity, high output, and suppression of output decrease during repeated charge / discharge use. In particular, a positive electrode material having a large bulk density is required for high capacity.
[0007]
However, LiCoO disclosed in Patent Document 2₂In the positive electrode material in which the surface of the primary particles is coated with boron, the output reduction during repeated charge / discharge use cannot be sufficiently suppressed. In the positive electrode materials disclosed in Examples of Patent Document 1 and Patent Document 3, it is difficult to increase the capacity because the bulk density is small, and sufficiently suppress the decrease in output during repeated charge / discharge use. I can't.
[0008]
[Means for Solving the Problems]
As a result of intensive studies in view of the above problems, the present inventor has found that the lithium transition metal composite oxide containing boron and / or bismuth forms secondary particles, and the surface portion of the secondary particles compared to the overall composition. Lithium transition metal composite oxides with high concentrations of boron and bismuth have a high bulk density and a small specific surface area. Therefore, when used as a positive electrode material, a high capacity can be achieved. When used, the electrode resistance was lowered, and as a result, it was found that the output of the battery can be increased, and the present invention has been completed.
[0009]
That is, the gist of the present invention consists of secondary particles of lithium transition metal composite oxide containing boron and / or bismuth, and boron and bismuth with respect to the total of metal elements other than lithium, boron and bismuth on the surface portion of the secondary particles. Is a positive electrode material for a lithium secondary battery, characterized in that the total atomic ratio is 5 to 70 times the atomic ratio of the entire secondary particles.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
Examples of the lithium transition metal composite oxide containing boron and / or bismuth constituting the positive electrode material for a lithium secondary battery according to the present invention include a lithium transition metal oxide having a layered structure and a lithium transition metal composite oxide having a spinel structure And containing boron and / or bismuth. Among these, excess lithium exceeding the stoichiometric ratio of the lithium transition metal composite oxide is contained, and the atomic ratio (b / a) of the excess amount of lithium (a) and the total of boron and bismuth (b) ) Is preferably 0.1 ≦ b / a ≦ 5, particularly 0.1 ≦ b / a ≦ 4. The reason for this is not clear, but it is considered that boron and / or bismuth concentrated on the surface of the secondary particles are in the form of a composite compound with lithium. It is done. Note that the stoichiometric ratio of the lithium transition metal composite oxide means a numerical value when the composition is expressed in molar ratio.
[0011]
For example, LiMn₂O_FourLiNiO₂LiCoO₂In the case where bismuth and / or boron is contained in a lithium transition metal composite oxide having a layered structure represented by the above, the composition is represented by the general formula (4). Since the lithium stoichiometric ratio of the lithium transition metal composite oxide having this layered structure is 1, an excess amount of lithium (a) exceeding the stoichiometric ratio can be obtained by x-1. Further, the total (b) of boron and bismuth is obtained by v + w.
[0012]
[Formula 4]
Li_xMBi_vB_wO₂        (4)
[0013]
(In the formula, M represents a transition metal.)
LiMn₂O_FourIn the case of a lithium transition metal composite oxide having a spinel structure represented by bismuth and / or boron, the composition is represented by the general formula (5). Since the lithium stoichiometric ratio of the lithium transition metal composite oxide having this spinel structure is also 1, the lithium excess (a) exceeding the stoichiometric ratio can be obtained by x-1. Further, the total (b) of boron and bismuth is obtained by v + w.
[0014]
[Chemical formula 5]
Li_xM₂Bi_vB_wO_Four        (5)
[0015]
(In the formula, M represents a transition metal.)
As the lithium transition metal composite oxide containing boron and / or bismuth, those represented by the following general formula (1) are preferable.
[0016]
[Chemical 6]
Li_xM_yBi_vB_wO₂        (1)
[0017]
In general formula (1), M represents an element selected from a transition metal, an alkali metal, an alkaline earth metal, a halogen element, and a chalcogen element. Among these, those selected from Ni, Mn, Co, Al, Fe, Ga, Sn, V, Cr, Cu, Zn, Mg, Ti, Ge, Nb, Ta, Zr, and Ca are preferable, and Ni is more preferable. , Mn or Co.
[0018]
In the general formula (1), x is a number satisfying 0 <x ≦ 1.2, preferably 0 <x ≦ 1.15. If x is too large, the crystal structure may become unstable, or the battery capacity of a lithium secondary battery using this may be reduced. y is usually 0.9 or more and 1.1 or less, preferably 0.95 or more and 1.05 or less. v and w are each 0 or more, preferably 0.001 or more, more preferably 0.002 or more, and particularly preferably 0.005 or more. The upper limit is 0.1 or less, preferably 0.05 or less, more preferably 0.03 or less, and particularly preferably 0.02 or less. If v and w are too small, the effects of the present invention are not exhibited, and if they are too large, the battery performance may be deteriorated.
[0019]
One of v and w may be 0. The sum of v and w is greater than 0, preferably 0.001 or more, more preferably 0.002 or more, and usually 0.2 or less, preferably 0.15 or less, more preferably 0.1 or less. It is.
In the composition of general formula (1), the amount of oxygen may have some non-stoichiometry.
Among the general formula (1), those represented by the following general formula (2) are preferable.
[0020]
[Chemical 7]
Li_xM¹ _y1M² _y2Bi_vB_wO₂                (2)
[0021]
In general formula (2), M¹Represents at least one element selected from Ni, Mn and Co. M¹May be used alone or in combination of two or more. M²Is at least one element selected from Ni, Mn, Co, Al, Fe, Ga, Sn, V, Cr, Cu, Zn, Mg, Ti, Ge, Nb, Ta, Zr and Ca (referred to as a substituted metal element) May be present). M²Preferred is Al, Co, Fe, Mg, Ga, Ti, or Ca. Al, Co or Mg, particularly Al or Co, and further Co are preferable. M²May be used alone or in combination of two or more.
[0022]
In general formula (2), x, v, and w represent the same as in general formula (1). y1 and y2 are 0 <y1, 0 ≦ y2, and y1 + y2 is usually 0.9 or more and 1.1 or less, preferably 0.95 or more and 1.05 or less.
In the composition of the general formula (2), the amount of oxygen may have some non-stoichiometry.
[0023]
Among the lithium transition metal composite oxides containing boron and / or bismuth of the general formula (2), those having a layered crystal structure and represented by the following general formula (3) containing lithium, nickel, and manganese are preferable. Composite oxide.
[0024]
[Chemical 8]
Li_xNi_αMn_βQ_{(1- α - β )}Bi_vB_wO₂        (3)
[0025]
In the general formula (3), Q represents a metal element that substitutes a part of the sites of Ni and Mn (such metal element may be hereinafter referred to as “substitution metal element”), and Q represents a transition Metal, alkali metal, alkaline earth metal, halogen element, chalcogen element, etc. are mentioned, especially Al, Fe, Ga, Sn, V, Cr, Co, Cu, Zn, Mg, Ti, Ge, Nb, Ta, Zr And elements such as Ca. Preferred as Q is Al, Co, Fe, Mg, Ga, Ti or Ca. Al, Co or Mg, particularly Al or Co, and further Co are preferable. Q may be used alone or in combination of two or more.
[0026]
In the general formula (3), x represents a number of 0 <x ≦ 1.2, preferably 0 <x ≦ 1.15. If x is too large, the crystal structure may become unstable, or the battery capacity of a lithium secondary battery using this may be reduced.
α is usually 0.3 ≦ α ≦ 0.8, preferably 0.3 ≦ α ≦ 0.7. β is preferably 0.05 or more, particularly 0.1 or more, and preferably 0.6 or less, particularly 0.45 or less. If β is too large, it becomes difficult to synthesize a single-phase lithium nickel manganese composite oxide. Conversely, if α is too large, the overall cost increases and the effect of the present invention does not appear remarkably.
[0027]
The molar ratio α / β of Ni / Mn is 0.7 or more, preferably 0.8 or more, particularly preferably 0.9 or more, and is 9 or less, preferably 8 or less, particularly preferably 6 or less.
The value of (1-α-β) is 0 or more, 0.5 or less, preferably 0.4 or less, and more preferably 0.3 or less. If the content of the substitutional metal element Q is too large, the capacity when used as an electrode for a battery is reduced, or in particular, when the transition metal element Q is Co, a large amount of resources that are scarce in resources and expensive are used. So it's not practical.
[0028]
v and w are each 0 or more, preferably 0.001 or more, more preferably 0.002 or more, and particularly preferably 0.005 or more. The upper limit is 0.05 or less, preferably 0.03 or less, and more preferably 0.02 or less. If v and w are too small, the effect of the present invention is not exhibited, and if it is too large, the performance as a battery electrode may be deteriorated. One of v and w may be 0. The sum of v and w is greater than 0, preferably 0.001 or more, more preferably 0.002 or more, and usually 0.2 or less, preferably 0.15 or less, more preferably 0.1 or less. It is.
In the composition of the general formula (3), the amount of oxygen may have some non-stoichiometry.
[0029]
The lithium transition metal composite oxide containing boron and / or bismuth forms secondary particles. The secondary particles show a single crystal phase and are characterized by the presence of concentrated bismuth and boron on the surface portion.
Specifically, the atomic ratio of the total of boron and bismuth to the total of metal elements other than lithium, boron, and bismuth on the surface portion of the secondary particle is the sum of the metal elements other than lithium, boron, and bismuth of the entire secondary particle. 5 to 70 times the total atomic ratio of boron and bismuth with respect to. This ratio is preferably 8 times or more, and the upper limit is preferably 60 times or less, particularly preferably 50 times or less. If this ratio is too small, the effect of improving the battery performance is small. On the other hand, if the ratio is too large, powder characteristics such as battery performance and bulk density are deteriorated.
[0030]
The analysis of the composition of the surface part of the secondary particles is performed by X-ray photoelectron spectroscopy (XPS) using AlKα as an X-ray source under the conditions of an analysis area of 0.8 mm diameter and an extraction angle of 45 degrees. Although the range (depth) that can be analyzed varies depending on the composition of the secondary particles, it is usually 0.1 nm to 50 nm, particularly 1 nm to 10 nm for the positive electrode active material. Therefore, in the present invention, the surface portion of the secondary particle indicates a measurable range under these conditions.
[0031]
The average particle size (average secondary particle size) of the secondary particles is usually 1 μm or more, preferably 4 μm or more, usually 50 μm or less, preferably 40 μm or less. The average secondary particle diameter can be measured by a known laser diffraction / scattering particle size distribution measuring device, and examples of the dispersion medium used in the measurement include a 0.1 wt% sodium hexametaphosphate aqueous solution. . The particle size of the secondary particles can be controlled, for example, by production conditions such as spray conditions such as a gas-liquid ratio in a spray drying process described later. On the other hand, if the particle size of the secondary particles is too small, the cycle characteristics and safety tend to be lowered. If the particle size is too large, the internal resistance is increased and it is difficult to produce sufficient output.
[0032]
The average particle size (average primary particle size) of the primary particles forming the secondary particles is usually 0.01 μm or more, preferably 0.02 μm or more, more preferably 0.1 μm or more, usually 10 μm or less, preferably 5 μm or less, More preferably, it is 3 μm or less. The average primary particle size can be measured by scanning electron microscope (SEM) observation. The size of the primary particles can be controlled by the production conditions such as the firing temperature, firing time and firing atmosphere. If the primary particle size is too small, side reactions and the like on the surface are likely to occur, so cycle characteristics and the like tend to decrease. If it is too large, rate characteristics and capacity tend to decrease due to inhibition of lithium diffusion and insufficient conductive paths. It is in.
[0033]
The specific surface area of the secondary particles composed of a lithium transition metal composite oxide containing boron and / or bismuth is largely different depending on the composition ratio and contained elements, but cannot be generally stated.²/ G or more, preferably 0.2 m²/ G or more, more preferably 0.3 m²/ G or more. If the specific surface area is too small, it means that the primary particle size is increased, that is, the rate characteristics and the capacity tend to decrease, which is not preferable. Also, even if the specific surface area is too large, the cycle characteristics and the like tend to be reduced, so normally 8 m²/ G or less, preferably 5 m²/ G or less, more preferably 2 m²/ G or less.
[0034]
The specific surface area is measured by a known BET type powder specific surface area measuring device. Specifically, nitrogen is used for the adsorption gas and helium is used for the carrier gas, and BET one-point measurement by the continuous flow method is performed. First, the powder sample is heated and deaerated with a mixed gas at a temperature of 450 ° C. or lower, and then cooled to liquid nitrogen temperature to adsorb the mixed gas of helium and nitrogen. This is heated to room temperature with water, and the adsorbed nitrogen gas is desorbed, detected by a thermal conductivity detector, the amount is determined as a desorption peak, and is calculated as the specific surface area of the sample.
[0035]
Further, the tap density of the secondary particles composed of the lithium transition metal composite oxide containing boron and / or bismuth according to the present invention is about 200 times tapped by putting about 8 g of the lithium transition metal composite oxide powder into a 10 ml graduated cylinder ( Measured). The height at which the graduated cylinder is dropped is 1 to 5 cm, and the material under which the graduated cylinder is dropped is not particularly limited, and the interval between drops is 50 to 500 times / minute. The tap density varies greatly depending on the composition ratio and contained elements, so it cannot be generally stated, but usually 0.8 g / cm.^ThreeOr more, preferably 1.6 g / cm^ThreeOr more, more preferably 1.8 g / cm^ThreeOr more, most preferably 2.0 g / cm^ThreeThat's it. When the tap density is low, the amount of the positive electrode material per unit volume is small, and when a secondary battery is produced, the volume of the battery becomes large in order to ensure a certain energy capacity. Also, if the tap density is low, only a low energy capacity can be obtained when attempting to reduce the size of the battery. Therefore, it is preferable that the tap density is large, but in reality it is 3.0 g / cm.^ThreeHereinafter, usually 2.5 g / cm^ThreeIt is as follows.
[0036]
A secondary particle comprising a lithium transition metal composite oxide containing boron and / or bismuth is a raw material mixture containing a metal element constituting the target lithium transition metal composite oxide and a compound containing boron and / or bismuth. After being formed into particles, it can be produced by firing at a temperature higher than the melting point of the boron compound and bismuth compound using the molded product as a raw material.
As the raw materials, various kinds of materials such as oxides of the above elements; inorganic salts such as carbonates, sulfates, nitrates, and phosphates; halides; organic salts and the like can be used.
[0037]
As a compound containing lithium, Li₂CO_Three, LiNO_Three, Inorganic lithium salts such as Li acetate; LiOH, LiOH.H₂Lithium hydroxide such as O; Lithium halide such as LiCl and LiI; Li₂Examples thereof include inorganic lithium compounds such as O, and organic lithium compounds such as alkyl lithium and fatty acid lithium. The lithium compound may be soluble in the solvent. Among these, Li is preferable.₂CO_Three, LiNO_Three, LiOH · H₂O, Li acetate. In addition, when mixing raw materials by a wet method, LiOH · H₂O is preferably used. LiOH ・ H₂O is water-soluble, and when the dispersion medium is water, it not only improves the diffusion efficiency and uniformity in the dispersion medium, but is a compound that does not contain N, S, etc., so that during firing, NOx, SOx, etc. It also has the advantage of not generating harmful substances. These may be used alone or in combination of two or more.
[0038]
As a compound containing nickel, Ni (OH)₂, NiO, NiOOH, NiCO_Three・ 2Ni (OH)₂・ 4H₂O, NiC₂O_Four・ 2H₂O, Ni (NO_Three)₂・ 6H₂O, NiSO_Four, NiSO_Four・ 6H₂O, fatty acid nickel, nickel halide, etc. can be mentioned. Above all, Ni (OH)₂, NiO, NiOOH, NiCO_Three・ 2Ni (OH)₂・ 4H₂O, NiC₂O_Four・ 2H₂A compound that does not contain N and S such as O is preferable because it does not generate harmful substances such as NOx and SOx in the firing step. Ni (OH) is particularly preferable from the viewpoint that it can be obtained as an industrial raw material at a low cost and that the reactivity is high when firing.₂, NiO, NiOOH. These may be used alone or in combination of two or more.
[0039]
As a compound containing manganese, Mn_ThreeO_Four, Mn₂O_Three, MnO₂, MnOOH, MnCO_Three, Mn (NO_Three)₂, MnSO_Four, Organic manganese compounds, manganese hydroxides, manganese halides, and the like. Among these manganese compounds, Mn₂O_Three, MnO₂, Mn_ThreeO_FourIs preferable because it has a valence close to the manganese oxidation number of the composite oxide that is the final object.
[0040]
Examples of the compound containing boron include boric acid, boron, boron halide, boron carbide, boron nitride, boron oxide, boron halide organic complex, organic boron compound, alkylboric acid, and boranes. Any of the above can be used as long as it is a boron compound having a melting point lower than the firing temperature when producing a lithium transition metal composite oxide containing boron and / or bismuth or a boron compound that produces it. Of these boron compounds, boric acid and boron oxide are preferred because they can be obtained at low cost and are easy to handle. These may be used alone or in combination of two or more.
[0041]
Examples of the compound containing bismuth include bismuth metal, bismuth oxide, bismuth halide, bismuth carbide, bismuth nitride, bismuth hydroxide, bismuth chalcogenide, bismuth sulfate, bismuth nitrate, and organic bismuth compounds. Any of the above can be used as long as it is a bismuth compound having a melting point lower than the firing temperature at the time of producing a lithium transition metal composite oxide containing boron and / or bismuth or a bismuth compound that produces it. Among these bismuth compounds, bismuth oxide is preferable because it can be obtained at a low cost and is easy to handle.₂O_ThreeIs preferred. These may be used alone or in combination of two or more.
[0042]
The mixing ratio of these raw materials is appropriately selected according to the composition ratio of the target lithium transition metal composite oxide containing boron and / or bismuth.
Boron and bismuth may be appropriately adjusted in consideration of defects caused by volatilization in the synthesis process and contamination as impurities from the raw material. Specifically, the molar ratio (v) of bismuth present in the reaction system. Is usually 0 ≦ v ≦ 0.2, preferably 0 ≦ v ≦ 0.1, and particularly preferably 0 ≦ v ≦ 0.05. Similarly, the molar ratio (w) of boron present in the reaction system is usually 0 ≦ w ≦ 0.2, preferably 0 ≦ w ≦ 0.1, particularly preferably 0 ≦ w ≦ 0.05. . Further, the atomic ratio (b / a) of lithium (a) existing in excess beyond the stoichiometric ratio of the lithium transition metal composite oxide and the total (b) of boron and bismuth is 0.15 ≦ b / a It is preferable to mix the raw materials at a ratio such that ≦ 5 because secondary particles having a large bulk density can be easily produced.
[0043]
The method for mixing the raw materials is not particularly limited, and may be wet or dry. For example, a method using an apparatus such as a ball mill, a vibration mill, or a bead mill can be used. A water-soluble raw material such as lithium hydroxide may be mixed with other solid raw materials as an aqueous solution. Wet mixing is preferable because more uniform mixing is possible and the reactivity can be increased in the firing step to be provided later.
[0044]
The mixing time varies depending on the mixing method and cannot be generally specified. However, it is sufficient that the raw materials are uniformly mixed at the particle level. For example, in a ball mill (wet or dry type), the bead mill (wet type) is usually about 1 hour to 2 days. In the continuous method), the convection time is usually about 0.1 to 6 hours.
As the degree of pulverization, the particle diameter of the raw material particles serves as an index, but this is usually 2 μm or less, preferably 1 μm or less, and more preferably 0.5 μm or less. If the average particle size of the solid material in the dispersion medium containing the raw material in the wet mixing (hereinafter sometimes referred to as a slurry) is too large, not only the reactivity in the firing step is reduced, but also the dry powder in the spray drying described later. The sphericity of the body tends to decrease and the final powder packing density tends to be low. This tendency becomes particularly remarkable when trying to produce granulated particles having an average particle diameter of 50 μm or less. Further, making particles smaller than necessary leads to an increase in the cost of pulverization, so the average particle size of the solid matter in the slurry is usually 0.01 μm or more, preferably 0.02 μm or more, more preferably 0.1 μm or more. And
[0045]
The raw material mixture is formed into particles. The method for producing the particulate matter is not particularly limited as long as it is a method capable of obtaining a particulate matter containing a metal element constituting the target lithium transition metal composite oxide and a compound containing boron and / or bismuth. . For example, by a method of spray drying a wet mixture of raw materials, a method of generating a precipitate from a raw material aqueous solution by a coprecipitation method, and a method of drying this, a method of granulating a dry mixture of raw materials using a small amount of water or a binder Obtainable. Spray drying is preferable from the viewpoints of uniformity of the generated particulate matter, powder flowability, powder handling performance, and the ability to efficiently form secondary particles.
[0046]
Specifically, a method of producing particles containing a compound containing lithium and a compound containing a transition metal by a spray-drying method, and dry-mixing this with a compound containing boron and / or a compound containing bismuth, lithium And a method of producing a particulate material by a spray drying method from a slurry containing a compound containing a compound, a compound containing a transition metal, a compound containing boron and / or a compound containing bismuth.
[0047]
The average particle size of the particulate matter is preferably 50 μm or less, more preferably 40 μm or less. However, since it tends to be difficult to obtain a too small particle size, it is usually 4 μm or more, preferably 5 μm or more. In the case of producing a particulate material by the spray drying method, the particle size can be controlled by appropriately selecting the spray format, the pressurized gas flow supply rate, the slurry supply rate, the drying temperature, and the like.
[0048]
Secondary particles formed by sintering primary particles by firing a particulate material containing a metal element constituting a target lithium transition metal composite oxide and a compound containing boron and / or bismuth. Obtainable. For firing, for example, a box furnace, a tubular furnace, a tunnel furnace, a rotary kiln or the like can be used. Firing is usually divided into three parts: temperature rise, maximum temperature hold, and temperature drop. Further, the second maximum temperature holding portion is not necessarily limited to one time, and two or more steps may be taken depending on the purpose. Twice the crushing process to eliminate agglomeration to the extent that the secondary particles are not broken, or the crushing process to crush the primary particles or fine particles to a finer powder than the primary particles. Or you may repeat more. However, when the pulverization step is performed, a secondary particle formation step is performed by spray drying or the like before the subsequent firing.
[0049]
The temperature raising portion normally raises the temperature inside the furnace at a temperature raising rate of 1 to 5 ° C./min. If it is too slow, it takes time and is industrially disadvantageous. However, if it is too early, the furnace temperature does not follow the set temperature depending on the furnace.
[0050]
In the maximum temperature holding portion, the firing temperature is usually 500 ° C. or higher, preferably 600 ° C. or higher, more preferably 800 ° C. or higher. If the temperature is too low, it tends to require a long firing time in order to obtain a lithium transition metal composite oxide having good crystallinity. On the other hand, if the temperature is too high, the lithium transition metal composite oxide is vigorously sintered and fired. The resulting pulverization / pulverization yield is poor, resulting in industrial disadvantages, or the production of lithium transition metal composite oxides with many defects such as oxygen vacancies. The lithium transition metal composite oxides are used as positive electrode active materials. Since the battery capacity of the lithium secondary battery may be reduced or deteriorate due to the collapse of the crystal structure due to charge / discharge, it is usually 1100 ° C. or lower, preferably 1000 ° C. or lower.
[0051]
The holding time at the maximum temperature holding portion is usually selected from a wide range of 1 hour or more and 100 hours or less, but in order to obtain secondary particles having a high concentration of boron and / or bismuth in the surface portion, 80 hours or less. In particular, it is preferable to make it 50 hours or less. In particular, it is preferably 30 hours or less, particularly 20 hours or less, more preferably 15 hours or less. If the firing time is too long, boron and bismuth may not be concentrated on the surface of the secondary particles and may be distributed uniformly throughout the secondary particles. If the firing time is too short, lithium having good crystallinity may be obtained. It is difficult to obtain a transition metal composite oxide.
[0052]
In the temperature lowering portion, the temperature in the furnace is usually decreased at a temperature decreasing rate of 0.1 to 5 ° C / min. If it is too slow, it takes time and is industrially disadvantageous. If it is too early, the uniformity of the object tends to be lacking or the container tends to deteriorate.
[0053]
In the lithium transition metal composite oxide containing boron and / or bismuth according to the present invention, in particular, the lithium nickel manganese composite oxide containing boron and / or bismuth, the bulk density such as tap density varies depending on the firing atmosphere. The atmosphere at the time is preferably an atmosphere having an oxygen concentration of 10 to 80% by volume such as air, more preferably 10 to 50% by volume. If the oxygen concentration is too high, the bulk density of the resulting lithium transition metal composite oxide containing boron and / or bismuth may be reduced.
[0054]
In the present invention, after forming the particulate matter, the boron and / or bismuth contained in the particulate matter is melted by firing at a temperature equal to or higher than the melting point of the boron compound and / or bismuth compound used as a raw material. This is achieved by finding that boron and / or bismuth eventually concentrate on the surface of the secondary particle because it diffuses to the surface of the secondary particle while promoting the sintering of the particle. Such secondary particles cannot be obtained even if the raw material mixture powder is directly formed without being formed into particles, or the raw material mixture is press-molded.
[0055]
The lithium transition metal composite oxide containing boron and / or bismuth obtained in this way is composed of secondary particles that are densely sintered so that the primary particles are fused together. The tap density is high compared to things. For this reason, the amount of positive electrode material per unit volume can be increased. Moreover, if this is used for the positive electrode material of a secondary battery, the energy capacity per battery volume can be increased, and the battery can be miniaturized. In addition, on the surface of the secondary particles according to the present invention, a resistance layer containing nickel at the lithium site is formed, and the resistance layer becomes gradually smaller as the resistance layer gradually disappears by repeated charge and discharge. Therefore, it is assumed that the output is prevented from decreasing due to repeated charge and discharge.
[0056]
The positive electrode material according to the present invention is used for a positive electrode of a lithium secondary battery. The positive electrode is usually formed by forming a positive electrode active material layer containing a positive electrode material, a binder, and a conductive agent on a current collector. In the present invention, the positive electrode active material is the above-described positive electrode material for a lithium secondary battery. The positive electrode active material layer is usually formed by forming the above-described constituents into a sheet and press-bonding the constituents to a current collector, or preparing a slurry containing the above-described constituents, and applying and drying the slurry on the current collector. Or the like. The positive electrode active material layer obtained by coating and drying is preferably consolidated by a roller press or the like in order to increase the packing density of the electrode material.
[0057]
The proportion of the positive electrode material in the positive electrode active material layer is usually 10% by weight or more, preferably 30% by weight or more, and usually 99.9% by weight or less, preferably 99% by weight or less. If the amount of the positive electrode material is too large, the strength of the positive electrode tends to be insufficient. If the amount is too small, the capacity may be insufficient.
[0058]
Examples of the conductive agent used for the positive electrode include natural graphite, artificial graphite, and acetylene black. The ratio of the conductive agent in the active material layer is usually 0.1% by weight or more, preferably 1% by weight or more, and usually 50% by weight or less, preferably 10% by weight or less. If the amount of the conductive agent is too large, the capacity may be insufficient, and if the amount is too small, the electrical conductivity may be insufficient.
[0059]
Examples of the binder used for the positive electrode include polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl acetate, polymethyl methacrylate, polyethylene, and nitrocellulose. The ratio of the binder in the positive electrode active material layer is usually 0.1% by weight or more, preferably 1% by weight or more, and usually 60% by weight or less, preferably 40% by weight or less. If the amount is too large, the capacity may be insufficient. If the amount is too small, the strength may be insufficient.
[0060]
Moreover, N-methylpyrrolidone, tetrahydrofuran, dimethylformamide, water, etc. can be mentioned as a solvent used when preparing the slurry for forming a positive electrode active material layer. Examples of the material for the positive electrode current collector include aluminum and stainless steel, and preferably aluminum.
[0061]
The lithium secondary battery according to the present invention usually has the positive electrode, the negative electrode, and the electrolyte.
For the negative electrode, a negative electrode active material, a binder, and a negative electrode active material layer containing a conductive agent as necessary are formed on a current collector, or a metal foil such as a lithium alloy such as lithium metal or lithium-aluminum alloy is used. It is done.
[0062]
A carbon material is preferably used as the negative electrode active material. Examples of the carbon material include natural graphite and pyrolytic carbon. The material for the negative electrode current collector is preferably copper. Examples of the binder and conductive agent used for the negative electrode are the same as those used for the positive electrode. The negative electrode preferably has a negative electrode active layer containing a carbon material formed on a current collector.
[0063]
Examples of the electrolyte include an electrolytic solution, a solid electrolyte, and a gel electrolyte, but an electrolytic solution, particularly a nonaqueous electrolytic solution is preferable. Examples of the nonaqueous electrolytic solution include those obtained by dissolving various electrolytic salts in a nonaqueous solvent. As an electrolytic salt, LiCiO_Four, LiAsF₆, LiPF₆, LiBF_Four, LiBr, LiCF_ThreeSO_ThreeAnd lithium salts such as Examples of the non-aqueous solvent include tetrahydrofuran, 1,4-dioxane, dimethylformamide, acetonitrile, benzonitrile, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, and the like. These electrolytic salts and non-aqueous solvents may be used alone or in combination of two or more.
Usually, a separator is provided between the positive electrode and the negative electrode. Examples of separators include microporous polymer films composed of polymers such as polytetrafluoroethylene, polyethylene, polypropylene, and polyester, non-woven cloth filters such as glass fibers, and composite non-woven cloth filters made of glass fibers and polymer fibers. Can do.
[0064]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not restrict | limited to a following example, unless the summary is exceeded.
[0065]
<Battery evaluation>
<A. Production of positive electrode and capacity confirmation>
75 parts by weight of lithium nickel manganese composite oxide obtained in the examples or comparative examples described later, 20 parts by weight of acetylene black, and 5 parts by weight of polytetrafluoroethylene powder are thoroughly mixed in a mortar to form a thin sheet. Was punched out using punches of 9 mmφ and 12 mmφ. At this time, the total weight was adjusted to about 8 mg and about 18 mg, respectively. This was crimped to Al expanded metal to obtain a positive electrode.
The positive electrode punched out to 9 mmφ was used as a test electrode, and a coin cell was assembled using Li metal as a counter electrode. In this coin cell, 0.2mA / cm²The battery is charged to 4.2 V at a constant current (reaction for releasing lithium ions from the positive electrode), and then 0.2 mA / cm.²Was discharged at a constant current of 3.0 V (reaction to occlude lithium ions in the positive electrode). The initial charge capacity per unit weight of the positive electrode active material at this time is Qs (C) [mAh / g], the initial discharge capacity is Qs (D) [mAh / g], and the initial charge and discharge capacity E [%] = Qs ( D) / Qs (C) was determined.
[0066]
<B. Production of negative electrode and capacity confirmation>
92.5 parts by weight of graphite powder (d002 = 3.35 kg) having an average particle size of about 8 to 10 μm and 7.5 parts by weight of polyvinylidene fluoride were mixed, and N-methylpyrrolidone was added thereto to form a slurry. This slurry was applied to one side of a copper foil having a thickness of 20 μm, dried to evaporate the solvent, then punched out to 12 mmφ, 0.5 ton / cm²A negative electrode was produced by pressing the material.
A battery cell is assembled with this negative electrode as a test electrode and Li metal as a counter electrode, and 0.5 mA / cm²The initial storage capacity per unit weight of the negative electrode active material when Li ions were stored in the negative electrode until the voltage became 0 V at a constant current of Qf [mAh / g].
[0067]
<C. Coin cell assembly and battery performance evaluation>
After placing a positive electrode punched to 12 mmφ on the positive electrode can, placing a porous polyethylene film with a thickness of 25 μm on it as a separator, holding it with a polypropylene gasket, placing a negative electrode, and placing a spacer for adjusting the thickness After adding a non-aqueous electrolyte into the battery and sufficiently impregnating it, the negative electrode can was placed and the battery was sealed.
As the non-aqueous electrolyte, a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of 3: 7 is mixed with lithium hexafluorophosphate (LiPF).₆) Was dissolved to 1 mol / L.
The balance between the weight of the positive electrode active material and the weight of the negative electrode active material was set so as to satisfy the following formula.
[0068]
[Expression 1]
Positive electrode active material weight [g] / Negative electrode active material weight [g]
= (Qf [mAh / g] /1.2) / Qs (C) [mAh / g]
[0069]
<D. Cycle test>
The 1 hour rate current value (1C) of the battery was set as in the following equation, and the following measurements were performed.
[0070]
[Expression 2]
1C [mA] = Qs (D) × positive electrode active material weight [g]
[0071]
First, a constant current 0.2C charge / discharge cycle and a constant current 1C charge / discharge cycle are performed at room temperature, followed by a constant current 0.2C charge / discharge cycle at a high temperature of 60 ° C., and then a constant current 1C charge / discharge cycle. A test was conducted. The upper limit of charging was 4.1 V, and the lower limit voltage was 3.0 V.
At this time, the discharge capacity at the first cycle of the 1C charge / discharge 100 cycle test portion at 60 ° C. is Qh (1), the discharge capacity at the 100th cycle is Qh (100), and the high-temperature cycle capacity maintenance rate P [% ] Was requested.
[0072]
[Equation 3]
P [%] = {Qh (100) / Qh (1)} × 100
[0073]
<E. Room temperature resistance measurement>
[Expression 4]
Conditioning current value I [mA] = Qs (D) [mAh / g] × positive electrode active material weight M [g] / 5
[0074]
With respect to the obtained coin cell, initial conditioning of charge / discharge 2 cycles was performed with the conditioning current value I obtained by the above formula as the charge upper limit voltage 4.1 V and the discharge lower limit voltage 3.0 V, and in the second cycle at that time Discharge capacity Qs per unit weight of positive electrode active material₂(D) [mAh / g] was measured, 1C was set based on the following formula, and the following measurements were performed.
[0075]
[Equation 5]
1C [mA] = Qs₂(D) [mAh / g] x cathode active material weight M [g]
[0076]
After sufficiently relaxing the battery in a room temperature atmosphere at 25 ° C., the battery was charged with a constant current of 1/3 C [mA] for 108 minutes, allowed to stand for 1 hour, and then discharged with a constant current of 3 C for 10 seconds.
The voltage 10 seconds after the discharge at this time is V [mV], and the voltage before the discharge is V₀[mV], the difference ΔV [mV] = V [mV] −V₀[mV] was calculated, and the resistance R [Ω] = ΔV [mV] / 3C [mA] was calculated using the discharge current 3C [mA]. As this resistance R [Ω] is smaller, effects such as excellent charging characteristics at room temperature and advantageous for rapid charging can be obtained.
This resistance measurement is <D. It was performed before and after the cycle test>, and the room temperature resistance value before and after the cycle test and the rate of change thereof were determined.
[0077]
<Example 1>
LiOH ・ H₂O, NiO, Mn₂O_Three, Co (OH)₂, H_ThreeBO_ThreeAre mixed so as to be Li: Ni: Mn: Co: B = 1.05: 0.65: 0.15: 0.20: 0.010 (molar ratio), and pure water is added thereto to obtain a solid. A slurry having a partial concentration of 25% by weight was prepared. After pulverization using a circulating medium agitation type wet pulverizer until the average particle size of the solid content in the slurry becomes 0.30 μm, spray drying is performed using a four-fluid nozzle type spray dryer, Obtained. In addition, air was used as the drying gas at the time of spray drying, the drying gas introduction amount was 1200 L / min, and the drying gas inlet temperature was 90 ° C.
[0078]
About 8 g of the particulate matter obtained by spray drying is placed in an alumina crucible having a diameter of 50 mm, placed in an atmosphere firing furnace, and air at a flow rate of 9 L / min is circulated, while the maximum temperature is 830 at a temperature rising rate of 5 ° C./min. The temperature was raised to 0 ° C. and held at 830 ° C. for 10 hours, and then the temperature was lowered at a rate of temperature reduction of 5 ° C./min to obtain a lithium nickel manganese composite oxide (average particle size 8 μm) having a substantially charged molar ratio composition. This lithium nickel manganese composite oxide was confirmed to be a single phase having a layered structure by a powder X-ray diffraction pattern.
[0079]
About 5 g of the obtained lithium nickel manganese composite oxide was put in a 10 ml glass graduated cylinder, and the powder filling density (tap density) after tapping 200 times was measured. As a result, it was 1.89 g / cc.
In addition, the BET specific surface area of this composite oxide was measured using an “AMS8000 type fully automatic powder specific surface area measuring device” manufactured by Ritsu Okura.²/ G. Furthermore, the composition analysis of the secondary particle surface of this composite oxide was performed by X-ray photoelectron spectroscopy (XPS) (Physical Electronics X-ray photoelectron spectrometer “ESCA-5500MC”, X-ray source: AlKα, analysis area: 0.8 mm. As a result, the atomic ratio of boron on the surface of the secondary particles was 32 times the atomic ratio of boron in the entire secondary particles (B / (Ni + Mn + Co)).
A lithium secondary battery was produced using the obtained lithium nickel manganese composite oxide and evaluated. The results are shown in Table-1.
[0080]
<Example 2>
LiOH / H as raw material₂O, NiO, Mn₂O_Three, Co (OH)₂, Bi₂O_ThreeExcept that Li: Ni: Mn: Co: Bi = 1.05: 0.65: 0.15: 0.20: 0.020 (molar ratio) was used. Similarly, a single-phase lithium nickel manganese composite oxide was obtained.
As a result of measuring various physical properties in the same manner as in Example 1, the powder packing density (tap density) was 1.90 g / cc, and the BET specific surface area was 0.60 m.²/ G, the atomic ratio of bismuth on the secondary particle surface to the atomic ratio of bismuth of the entire secondary particle (Bi / (Ni + Mn + Co)) was 9 times.
A lithium secondary battery was produced using the obtained lithium nickel manganese composite oxide and evaluated. The results are shown in Table-1.
[0081]
<Comparative Example 1>
A lithium nickel manganese composite oxide was obtained in the same manner as in Example 1 except that boric acid was not added. The obtained lithium nickel manganese composite oxide was confirmed to be a single phase of a layered structure by a powder X-ray diffraction pattern.
As a result of measuring various physical properties in the same manner as in Example 1, the powder packing density (tap density) was 1.73 g / cc, and the BET specific surface area was 0.69 m.²/ G.
A lithium secondary battery was produced using the obtained lithium nickel manganese composite oxide and evaluated. The results are shown in Table-1.
[0082]
<Example 3>
LiOH / H as raw material₂O, NiO, Mn₂O_Three, Co (OH)₂, Bi₂O_ThreeIs used in such an amount that Li: Ni: Mn: Co: B = 1.05: 0.33: 0.33: 0.33: 0.005 (molar ratio), and the maximum temperature during firing is 900. A single-phase lithium-nickel-manganese composite oxide was obtained in the same manner as in Example 1 except that the firing was performed at 0 ° C.
As a result of measuring various physical properties in the same manner as in Example 1, the powder packing density (tap density) was 1.70 g / cc, and the BET specific surface area was 0.80 m.²/ G, the atomic ratio of bismuth on the surface of the secondary particles to the atomic ratio of bismuth of the entire secondary particles (Bi / (Ni + Mn + Co)) was 44 times.
A lithium secondary battery was produced using the obtained lithium nickel manganese composite oxide and evaluated. The results are shown in Table-1.
[0083]
<Comparative example 2>
A lithium nickel manganese composite oxide was obtained in the same manner as in Example 3 except that bismuth was not added. The obtained lithium nickel manganese composite oxide was confirmed to be a single phase of a layered structure by a powder X-ray diffraction pattern.
As a result of measuring various physical properties in the same manner as in Example 1, the powder packing density (tap density) was 1.01 g / cc, and the BET specific surface area was 2.27 m.²/ G.
A lithium secondary battery was produced using the obtained lithium nickel manganese composite oxide and evaluated. The results are shown in Table-1.
[0084]
[Table 1]

[0085]
In Table 1, when Examples 1 and 2 and Comparative Example 1 are compared, boron or bismuth having a concentration of 5 to 70 times the positive electrode active material composition is concentrated on the surface of the secondary particles. The lithium nickel manganese composite oxide has a higher tap density and changes in the coin cell room temperature resistance before and after the 100 ° C. charge / discharge cycle test, as compared with other lithium nickel manganese composite oxides in which neither boron nor bismuth is present. It can be seen that the magnification is low and therefore advantageous as a positive electrode material for a lithium secondary battery. Comparing Example 3 and Comparative Example 2, similarly, Example 3 has a higher tap density, and the change rate before and after the 60 ° C. charge / discharge 100 cycle test of the coin cell room temperature resistance is low. In the composition such as Example 3 having a high manganese content, a comparatively low bulk density is obtained by concentrating boron or bismuth at 5 to 70 times the positive electrode active material composition on the secondary particle surface. It can be seen that even with the composition of 3, high bulk density could be realized. As in the reference example, it can be seen that the effect of the present invention is small in a composition having a high nickel content.
From Table 1, the lithium nickel manganese composite oxide obtained in the examples has a high powder tap density and a low specific surface area, and in addition, has excellent battery performance when used as a secondary battery. Was confirmed.
[0086]
【The invention's effect】
According to the present invention, it is possible to provide a high-performance (high capacity, high cycle characteristic, high rate characteristic, high storage characteristic, etc.) positive electrode material for a lithium secondary battery suitable as a positive electrode material for a lithium secondary battery at a low cost. it can. In particular, according to the present invention, it is possible to provide a lithium transition metal composite oxide having a bulk density higher than that conventionally synthesized. Furthermore, according to the present invention, it is possible to provide a positive electrode for lithium secondary batteries and a lithium secondary battery having high performance (high charge / discharge efficiency, low resistance, high output, etc.).

Claims (12)

It consists of secondary particles of lithium transition metal composite oxide containing boron and / or bismuth represented by the following general formula (3), and boron with respect to the total of metal elements other than lithium, boron and bismuth on the surface part of the secondary particles The total atomic ratio of bismuth and bismuth is 8 times or more the total atomic ratio of the secondary particles, and contains an excess of lithium with respect to the stoichiometric ratio of the lithium transition metal composite oxide. A positive electrode material for a lithium secondary battery, wherein an atomic ratio (b / a) of an excess amount (a) to a stoichiometric ratio and a total of boron and bismuth (b) (b / a) is 5 or less.
_{Li x Ni α Mn β Q (} 1- α - β) Bi v B w O 2 (3)
(In the formula, Q represents at least one element selected from Al, Fe, Ga, Sn, V, Cr, Co, Cu, Zn, Mg, Ti, Ge, Nb, Ta, Zr and Ca. x is 0. <X ≦ 1.2, α and β are 0.7 ≦ α / β ≦ 9, and 0 ≦ (1-α−β) ≦ 0.5, v is 0 ≦ v ≦ 0.1, and w is 0 ≦ represents a number satisfying the relationship of w ≦ 0.1 (provided that at least one of v and w is not 0).) The positive electrode material for a lithium secondary battery according to claim 1 , wherein α is 0.3 ≦ α ≦ 0.8. The positive electrode material for a lithium secondary battery according to claim 1 or 2 beta is characterized by a 0.05 ≦ β ≦ 0.6. Boron and / or lithium secondary according to any one of claims 1 to 3, a specific surface area of secondary particles of lithium transition metal composite oxide is less than 0.1 m ² / g or more 8m ² / g containing bismuth Positive electrode material for batteries. The lithium according to any one of claims 1 to 4 , wherein the tap density of secondary particles made of a lithium transition metal composite oxide containing boron and / or bismuth is 0.8 g / cm ³ or more and 3.0 g / cm ³ or less. Positive electrode material for secondary battery. The positive electrode material for a lithium secondary battery according to any one of claims 1 to 5 , wherein the secondary particles made of a lithium transition metal composite oxide containing boron and / or bismuth have an average particle size of 1 µm or more and 50 µm or less. A positive electrode for a lithium secondary battery, characterized by containing a positive electrode material and a binder for a lithium secondary battery according to any one of claims 1 to 6. A lithium secondary battery comprising the positive electrode for a lithium secondary battery according to claim 7 , a negative electrode, and an electrolyte. A method for producing a positive electrode material for a lithium secondary battery according to any one of claims 1 to 8 , comprising a metal element constituting a target lithium transition metal composite oxide, and boron and / or bismuth. The raw material mixture containing the compound is formed into particles and fired at a temperature higher than the melting point of the boron compound and bismuth compound used as the raw material to form a lithium transition metal composite oxide containing boron and / or bismuth. A method for producing a positive electrode material for a lithium secondary battery, characterized by producing secondary particles. The method for producing a positive electrode material for a lithium secondary battery according to claim 9 , wherein the firing is performed in an atmosphere having an oxygen concentration of 10 to 80% by volume. The boron raw material is at least one selected from the group consisting of boric acid, boron, boron halide, boron carbide, boron nitride, boron oxide, boron halide organic complex, organic boron compound, alkylboric acid, and borane. The manufacturing method of the positive electrode material for lithium secondary batteries of Claim 9 or 10 . The bismuth raw material is at least one selected from the group consisting of bismuth metal, bismuth oxide, bismuth halide, bismuth carbide, bismuth nitride, bismuth hydroxide, bismuth hydroxide, bismuth sulfate, bismuth nitrate, and organic bismuth compounds. The manufacturing method of the positive electrode material for lithium secondary batteries in any one of Claim 9 to 11 .