Positive electrode active material for lithium secondary battery and method for manufacturing same

Abstract

Provided is a positive electrode active material comprising lithium iron phosphate-based compound particles. The lithium iron phosphate-based compound particles have, according to the results of PSD analysis, an absolute value of a slope between a point where the particle size is an average particle size (D50) and a point where the particle size is a 90% volume cumulative particle size (D90) of 30 to 44.5 in a particle size distribution graph in which the x-axis represents particle size (μm) and the y-axis represents number%. When the positive electrode active material is applied to a battery, charge capacity, discharge capacity, and efficiency are increased, and internal resistance is reduced, thereby improving electrochemical performance of the battery.

Description

Cathode active material for lithium secondary batteries and method for manufacturing the same

[0001] The present invention relates to a positive electrode active material for a lithium secondary battery and a method for manufacturing the same. Specifically, the invention relates to a positive electrode active material comprising lithium iron phosphate-based compound particles having specific particle size-related characteristics and a method for manufacturing the same.

[0002] The present application claims the benefit of priority based on Korean Patent Application No. 10-2025-0031842 dated March 12, 2025, and includes all contents disclosed in the document of said Korean patent application as part of this specification.

[0003] With the recent rapid proliferation of battery-powered electronic devices such as mobile phones, laptop computers, and electric vehicles, the demand for small, lightweight, and relatively high-capacity rechargeable batteries is increasing rapidly. In particular, lithium-ion batteries are gaining prominence as power sources for portable devices due to their lightweight nature and high energy density. Consequently, active research and development efforts are underway to improve the performance of lithium-ion batteries.

[0004] In a lithium secondary battery, electrical energy is produced by oxidation and reduction reactions when lithium ions are inserted into or removed from the positive and negative electrodes, which are composed of active materials capable of lithium ion intercalation and deintercalation, with an organic or polymer electrolyte charged between them.

[0005] Lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMnO2 or LiMn2O4, etc.), and lithium iron phosphate compounds (LiFePO4) have been used as cathode active materials for lithium-ion batteries. Among these, lithium cobalt oxide (LiCoO2) is widely used and applied as a cathode active material for high-voltage applications due to its advantages of high operating voltage and excellent capacity characteristics. However, due to the rising price and supply instability of cobalt (Co), there are limitations to its mass use as a power source in fields such as electric vehicles, leading to the emergence of a need to develop cathode active materials that can replace it.

[0006] Unlike cathode active materials based on nickel, cobalt, and manganese, lithium iron phosphate-based cathode active materials based on iron and phosphoric acid are being actively researched as low-cost cathode active materials. However, lithium iron phosphate-based cathode active materials have the disadvantage of low energy density in batteries because they have lower operating voltage and specific capacity compared to lithium nickel, cobalt, and manganese oxide-based cathode active materials when applied to batteries. Additionally, compared to lithium nickel, cobalt, and manganese oxide-based cathode active materials, they have lower conductivity and undergo a two-phase reaction, so electrochemical efficiency must be considered as the phases differ during charging and discharging.

[0007] Accordingly, in order to actively utilize lithium iron phosphate-based cathode active materials, it is required to develop lithium iron phosphate-based cathode active materials that improve upon the aforementioned problems.

[0008] [Prior Art Literature]

[0009] [Patent Literature]

[0010] (Patent Document 1) Korean Published Patent Application No. 10-2015-0039016

[0011] The present invention aims to provide a positive electrode active material for a lithium secondary battery comprising lithium iron phosphate-based compound particles, wherein particle size-related characteristics that significantly affect electrochemical performance are controlled when applied to a battery.

[0012] According to the first aspect of the present invention,

[0013] The present invention provides a positive electrode active material comprising lithium iron phosphate-based compound particles.

[0014] In one embodiment of the present invention, the lithium iron phosphate-based compound particles, in a particle size distribution graph where the x-axis is particle size (μm) and the y-axis is number % in the PSD analysis results, have a particle size of average particle size (D 50 The fact that ) and the particle size is the volume cumulative 90% particle size (D 90 The absolute value of the slope between the points is 30 to 44.5.

[0015] In one embodiment of the present invention, the lithium iron phosphate-based compound particles have an average particle size (D) in the PSD analysis results. 50 ) is 0.2㎛ to 0.6㎛.

[0016] In one embodiment of the present invention, the lithium iron phosphate-based compound particles have a volume cumulative particle size of 10% (D) in the PSD analysis results. 10 ) is 0.15㎛ to 0.45㎛.

[0017] In one embodiment of the present invention, the lithium iron phosphate-based compound particles have a volume cumulative 90% particle size (D) in the PSD analysis results. 90 ) is 0.5㎛ to 1.0㎛.

[0018] In one embodiment of the present invention, the lithium iron phosphate-based compound particles have a single peak in a particle size distribution graph in PSD analysis results, where the x-axis represents particle size (μm) and the y-axis represents number %, and the particle size distribution graph has an asymmetric shape centered on the peak, and the particle size at the peak is the volume cumulative 90% particle size (D 90 10% of the cumulative volume particle size (D) compared to ) 10 It is close to ).

[0019] In one embodiment of the present invention, the lithium iron phosphate-based compound particles have an A value obtained from the following mathematical formula 1 of -0.05 to 0.2.

[0020] [Mathematical Formula 1]

[0021] A = S mean -(D 10 +D 50 ) / 2

[0022] Here, S mean ε is the average particle size (μm) of the primary particles in the SEM DX analysis results, and D 10 is the 10% volume cumulative particle size (㎛) in the PSD analysis results, and D 50 is the average particle size (㎛) in the PSD analysis results.

[0023] In one embodiment of the present invention, the lithium iron phosphate-based compound is represented by the following chemical formula 1.

[0024] [Chemical Formula 1]

[0025] Li 1+a Fe 1-x-y Mn x M y PO4

[0026] In the above chemical formula 1,

[0027] M is at least one element selected from the group consisting of V, Al, Ni, Co, Mg, Nb, Mo, W, Ti, Sr, Zr, B, Y and Zn, and

[0028] -0.1≤a≤0.1, 0≤x≤0.7, 0≤y≤0.1.

[0029] According to a second aspect of the present invention,

[0030] The present invention provides a method for manufacturing an anode active material comprising lithium iron phosphate-based compound particles.

[0031] In one embodiment of the present invention, the manufacturing method comprises: (1) mixing a raw material of a lithium iron phosphate-based compound, a carbon-based material, and a dispersant in a solvent; (2) spray-drying the mixture; (3) calcining the dried material; and (4) grinding the calcined material.

[0032] In one embodiment of the present invention, in step (1), 1 to 15 parts by weight of the carbon-based material is mixed based on 100 parts by weight of solids in the mixture.

[0033] In one embodiment of the present invention, in step (1), the dispersant is mixed in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of solids in the mixture.

[0034] In one embodiment of the present invention, the step of grinding the mixture before step (2) is further included, and the average particle size (D) of the solids in the mixture is determined by grinding. 50 ) is 0.5㎛ or less, and the maximum particle size of the solid content (D max ) is controlled to 7㎛ or less.

[0035] In one embodiment of the present invention, in step (2), spray drying is performed at a temperature of 80°C to 250°C.

[0036] In one embodiment of the present invention, in step (3), the firing is performed at 700°C to 900°C for 5 to 15 hours.

[0037] In one embodiment of the present invention, in step (4), grinding is performed at a grinding pressure of 0.5 bar to 3 bar.

[0038] According to the third aspect of the present invention,

[0039] The present invention provides a positive electrode comprising the positive electrode active material described above.

[0040] In the present invention, when analyzing the particle size of a positive electrode active material, PSD analysis and SEM DX analysis were utilized to identify particle size-related characteristics that have a significant effect on electrochemical performance when the positive electrode active material is applied to a battery. Specifically, a positive electrode active material according to one embodiment of the present invention has particle size-related characteristics in which the absolute value of the slope calculated according to this specification is 30 to 44.5, or the A value is -0.05 to 0.2.

[0041] When a positive electrode active material according to one embodiment of the present invention is applied to a battery due to the particle size-related characteristics described above, the charge capacity, discharge capacity, and efficiency are increased, and the internal resistance is reduced, thereby improving the electrochemical performance of the battery.

[0042] Figure 1 is a graph of particle size distribution obtained from PSD analysis results for the cathode active material prepared in Example 1.

[0043] Figure 2 is a particle size distribution graph obtained from the PSD analysis results for the cathode active material prepared in Example 2.

[0044] Figure 3 is a particle size distribution graph obtained from the PSD analysis results for the cathode active material prepared in Example 3.

[0045] Figure 4 is a particle size distribution graph obtained from the PSD analysis results for the cathode active material prepared in Example 4.

[0046] Figure 5 is a particle size distribution graph obtained from the PSD analysis results for the cathode active material prepared in Example 5.

[0047] Figure 6 is a graph of particle size distribution obtained from PSD analysis results for the cathode active material prepared in Comparative Example 1.

[0048] Figure 7 is a graph of particle size distribution obtained from PSD analysis results for the cathode active material prepared in Comparative Example 2.

[0049] Figure 8 is a particle size distribution graph obtained from the PSD analysis results for the cathode active material prepared in Comparative Example 3.

[0050] Figure 9 is a graph of particle size distribution obtained from PSD analysis results for the cathode active material prepared in Comparative Example 4.

[0051] Figure 10 is a graph of particle size distribution obtained from PSD analysis results for the cathode active material prepared in Comparative Example 5.

[0052] All embodiments provided according to the present invention can be achieved by the following description. It should be understood that the following description describes preferred embodiments of the present invention and that the present invention is not necessarily limited thereto.

[0053] Where measurement conditions and methods are not specifically described for the physical properties described in this specification, said physical properties are measured according to measurement conditions and methods generally used by a person skilled in the art in the relevant technical field.

[0054]

[0055] <Cathode Active Material>

[0056]

[0057] The present invention provides a positive electrode active material comprising lithium iron phosphate-based compound particles. In analyzing the particle size of the positive electrode active material, the present invention utilizes PSD analysis and SEM DX analysis. Through this, particle size-related characteristics that significantly affect electrochemical performance when applied to a battery are identified, thereby providing a positive electrode active material that satisfies these characteristics. While the PSD analysis focuses on aggregates to analyze the particle size distribution as a whole, the SEM DX analysis may focus on individual particles to analyze their individual particle sizes. Since the SEM DX analysis pertains to individual particles, the results of the SEM DX analysis are distinguished and indicated in this specification as per primary particles. Therefore, utilizing both sets of data allows for a more diverse range of analysis. When the positive electrode active material according to one embodiment of the present invention is applied to a battery, the charge capacity, discharge capacity, and efficiency increase, and the internal resistance decreases, thereby improving the electrochemical performance of the battery.

[0058] According to one embodiment of the present invention, in the PSD analysis results, the lithium iron phosphate-based compound particles, in a particle size distribution graph where the x-axis is particle size (μm) and the y-axis is number%, have a particle size of average particle size (D 50 The fact that ) and the particle size is the volume cumulative 90% particle size (D 90 The absolute value of the slope between the points is 30 to 44.5. Generally, the average particle size (D 50 When ), the number % is the volume cumulative 90% particle size (D 90 In terms of the fact that it is higher than the number % when ), the average particle size (D 50 The fact that ) and the particle size is the volume cumulative 90% particle size (D 90The slope between points ) can have a negative value. Specifically, the absolute value of the slope can be 30 or more, 30.1 or more, 30.2 or more, 30.3 or more, 30.4 or more, 30.5 or more, 44.5 or less, 44.4 or less, 44.3 or less, 44.2 or less, 44.1 or less, 44 or less, and 30 to 44.5, 30.3 to 44.2, or 30 to 44.5. Generally, the slope between any two points in a particle size distribution graph is not highly correlated with the electrochemical performance of the battery, but the technical feature has technical significance in that the difference in the slope between two points within a specific range has a significant effect on the electrochemical performance of the battery.

[0059] According to one embodiment of the present invention, the lithium iron phosphate-based compound particles have a single peak in a particle size distribution graph in PSD analysis results, where the x-axis represents particle size (μm) and the y-axis represents the number %. Here, the peak signifies the point where the trend changes from an upward trend to a downward trend. The particle size distribution graph has an asymmetric shape centered around the peak, and the minimum value of the particle size (D min ) and maximum value(D max When the particle size is divided into a differential region and a coarse region based on the center point of ), the peak is located in the differential region. The minimum value of the above particle size (D min ) refers to the minimum particle size detected in the measured particle size distribution, and the maximum value of the particle size (D max ) refers to the maximum particle size detected in the measured particle size distribution. In other words, the particle size at the peak is the 90% volume-cumulative particle size (D 90 10% of the cumulative volume particle size (D) compared to ) 10 It is close to ). Here, being close means that the absolute numerical difference is small, rather than the distance difference on a log10 scale as in Figure 1 below.

[0060] According to one embodiment of the present invention, the lithium iron phosphate-based compound particles have an average particle size (D) in the PSD analysis results.50 ) is 0.2㎛ to 0.6㎛. The above average particle size (D 50 ) refers to the particle size corresponding to 50% of the volume accumulation standard during PSD analysis. Specifically, the above average particle size (D 50 ) is 0.2㎛ or more, 0.25㎛ or more, 0.3㎛ or more, 0.35㎛ or more, 0.6㎛ or less, 0.55㎛ or less, 0.5㎛ or less, and may be 0.2㎛ to 0.6㎛, 0.25㎛ to 0.55㎛, or 0.3㎛ to 0.5㎛.

[0061] According to one embodiment of the present invention, the lithium iron phosphate-based compound particles have a volume cumulative particle size of 10% (D) in the PSD analysis results. 10 ) is 0.15㎛ to 0.45㎛. The above volume cumulative 10% particle size (D 10 ) refers to the particle size corresponding to the 10% standard of the volume accumulation during PSD analysis. Specifically, the above 10% volume accumulation particle size (D 10 ) is 0.15㎛ or more, 0.2㎛ or more, 0.25㎛ or more, 0.45㎛ or less, 0.4㎛ or less, 0.35㎛ or less, and may be 0.15㎛ to 0.45㎛, 0.2㎛ to 0.4㎛, or 0.25㎛ to 0.35㎛.

[0062] According to one embodiment of the present invention, the lithium iron phosphate-based compound particles have a volume cumulative particle size of 90% (D) in the PSD analysis results. 90 ) is 0.5㎛ to 1.0㎛. The above volume cumulative 90% particle size (D 90 ) refers to the particle size corresponding to 90% of the volume accumulation standard during PSD analysis. Specifically, the above 90% volume accumulation particle size (D 90 ) is 0.5㎛ or more, 0.55㎛ or more, 0.6㎛ or more, 1.0㎛ or less, 0.95㎛ or less, 0.9㎛ or less, and may be 0.5㎛ to 1.0㎛, 0.55㎛ to 0.95㎛, or 0.6㎛ to 0.9㎛.

[0063] The present invention goes beyond simply analyzing the particle size of a positive electrode active material in two ways and provides particle size-related characteristics by combining PSD analysis results and SEM DX analysis results. According to one embodiment of the present invention, the lithium iron phosphate-based compound particles have an A value obtained from the following Equation 1 of -0.05 to 0.2.

[0064]

[0065] [Mathematical Formula 1]

[0066] A = S mean -(D 10 +D 50 ) / 2

[0067]

[0068] Here, S mean is the average particle size (㎛) of the primary particles in the SEM DX analysis results, and D 10 is the 10% volume cumulative particle size (㎛) in the PSD analysis results, and D 50 ε is the average particle size (μm) in the PSD analysis results. Specifically, the above A value may be -0.05 or higher, -0.04 or higher, -0.03 or higher, 0.02 or higher, 0.2 or lower, 0.15 or lower, 0.1 or lower, or -0.05 to 0.2, -0.04 to 0.15, or -0.03 to 0.1. The above A value represents the deviation between the average size of the primary particles and the aggregate-based PSD analysis value, which is related to the degree of disintegration of the secondary particles and the electron-ion transport pathway within the electrode. In particular, the above technical feature has technical significance in that the difference in the A value within a specific range has a significant effect on the electrochemical performance of the battery.

[0069] According to one embodiment of the present invention, the lithium iron phosphate-based compound is represented by the following chemical formula 1.

[0070]

[0071] [Chemical Formula 1]

[0072] Li 1+a Fe1-x-y Mn x M y PO4

[0073]

[0074] In the above chemical formula 1,

[0075] M is at least one element selected from the group consisting of V, Al, Ni, Co, Mg, Nb, Mo, W, Ti, Sr, Zr, B, Y, and Zn. a is -0.1≤a≤0.1. Specifically, a can be -0.1≤a≤0.1, -0.08≤a≤0.08, or -0.05≤a≤0.05. x is 0≤x≤0.7. Specifically, x can be 0≤x≤0.7, 0≤x≤0.65, or 0≤x≤0.6. y is 0≤y≤0.1. Specifically, y can be 0≤y≤0.1, 0≤y≤0.08, or 0≤y≤0.05.

[0076] The above lithium iron phosphate-based compound particles mainly comprise a lithium iron phosphate-based compound of Formula 1, etc., and may further comprise a compound derived from a carbon-based material. The above compound derived from a carbon-based material refers to a compound obtained by mixing a carbon-based material with a raw material of a lithium iron phosphate-based compound and calcining it during the manufacturing process of a positive electrode active material. The above carbon-based material may help improve the electrical conductivity and physical properties of the particles. The above carbon-based material is not particularly limited as long as it is a material generally used in the relevant technical field. The above carbon-based material may be an amorphous carbon-based material, and may be, for example, sucrose; glucose; cellulose; lactose; polyvinyl alcohol; or a combination thereof. According to one embodiment of the present invention, the above lithium iron phosphate-based compound particles comprise 1% to 15%, 3% to 14%, or 5% to 13% of a compound derived from a carbon-based material based on the total weight of the particles.

[0077] The positive electrode active material according to one embodiment of the present invention has an excellent effect in improving the electrochemical performance of the applied battery, and this is attributed to the above-described characteristics of the particles constituting the positive electrode active material and the method of manufacturing the particles described below.

[0078]

[0079] Method for manufacturing positive electrode active material

[0080]

[0081] The present invention provides a method for manufacturing the above-described positive electrode active material comprising lithium iron phosphate-based compound particles. According to one embodiment of the present invention, the manufacturing method comprises the steps of: (1) mixing a raw material of a lithium iron phosphate-based compound, a carbon-based material, and a dispersant in a solvent; (2) spray-drying the mixture; (3) calcining the dried material; and (4) grinding the calcined material.

[0082] In step (1) above, the raw material for the lithium iron phosphate compound refers to the raw material used to form the lithium iron phosphate compound included in the final product particles. This raw material basically includes a lithium raw material, and may include an iron raw material, a phosphate raw material, etc. The raw material may be a material in a form commonly used in the relevant technical field, for example, a material in the form of a sulfate, nitrate, acetate, carbonate, oxalate, citrate, halide, hydroxide, or oxyhydroxide may be used. In addition, if manganese is included, a manganese raw material may also be mixed together, and if a dopant is included, a dopant raw material may also be mixed together.

[0083] In step (1) above, the raw material of the lithium iron phosphate compound may be mixed with a carbon-based material. The carbon-based material may help improve the electrical conductivity and physical properties of the particles. The carbon-based material is not particularly limited as long as it is a material commonly used in the relevant technical field. The carbon-based material may be an amorphous carbon-based material, for example, sucrose; glucose; cellulose; lactose; polyvinyl alcohol; or a combination thereof. According to one embodiment of the present invention, the carbon-based material is mixed in an amount of 1 to 15 parts by weight, 3 to 14 parts by weight, or 5 to 13 parts by weight based on 100 parts by weight of solids in the mixture.

[0084] In step (1) above, a dispersant may be mixed together with the raw material of the lithium iron phosphate compound and the carbon-based material. The dispersant may help prevent aggregation between particles in the solvent and help form a mixture in which each material is uniformly dispersed. The dispersant is not particularly limited as long as it is a material commonly used in the relevant technical field. The dispersant may be an acidic material and may include, for example, a material selected from citric acid, fumaric acid, adipic acid, succinic acid, tartaric acid, glutaric acid, maleic acid, oxalic acid, malonic acid, ascorbic acid, and combinations thereof. Additionally, the dispersant may be a polymeric material and may include, for example, polyethylene glycol (PEG) and hydrogenated nitrile butadiene rubber (HNBR). According to one embodiment of the present invention, the dispersant is mixed in an amount of 0.1 to 5 parts by weight, 0.5 to 3 parts by weight, and 1 to 2.5 parts by weight based on 100 parts by weight of solids in the mixture.

[0085] The raw materials of the above lithium iron phosphate-based compound and carbon-based materials are mixed in a solvent (e.g., water) to form a slurry. The solid content in the slurry may be 10% to 30% by weight, 15% to 30% by weight, or 15% to 25% by weight. The mixing of the solids in the slurry is not particularly limited as long as it is a method generally used in the relevant technical field. The mixing is intended to uniformly disperse various raw materials, and a milling device (e.g., a ball mill) may be utilized.

[0086] According to one embodiment of the present invention, in step (2), the slurry, which is a mixture, is ground before spray drying. The grinding process can control the particle characteristics of the dried product produced through subsequent spray drying. A milling device (e.g., a bead mill) may be used to evenly grind the solids in the slurry. By grinding, the maximum particle size (D) of the solids in the mixture max ) can be controlled to 7㎛ or less. In addition, the average particle size (D) of the solids in the mixture by the above grinding 50 ) can be controlled to 0.5㎛ or less.

[0087] In step (2) above, the slurry, which is a mixture, is spray-dried. According to one embodiment of the present invention, the spray drying is performed at a temperature of 80°C to 250°C, 80°C to 230°C, or 80°C to 200°C. In the spray drying, the temperature of the incoming hot air is set higher than the temperature of the outgoing hot air. The product dried through spray drying is dispersed with sufficient internal pores.

[0088] In step (3) above, the product dried by spray drying is fired. According to one embodiment of the present invention, the first firing is performed at 700°C to 900°C for 5 to 15 hours. Specifically, the temperature of the first firing is 700°C or higher, 710°C or higher, 720°C or higher, 730°C or higher, 740°C or higher, 750°C or higher, 900°C or lower, 890°C or lower, 880°C or lower, 870°C or lower, 860°C or lower, 850°C or lower, and may be 700°C to 900°C, 730°C to 880°C, 750°C to 850°C. In addition, the firing time may be 5 hours or more, 6 hours or more, 7 hours or more, 15 hours or less, 14 hours or less, 13 hours or less, or 5 hours to 15 hours, 6 hours to 14 hours, or 7 hours to 13 hours. The fired product, fired after spray drying, has the characteristic of being porous with a large particle size in the form of secondary particles.

[0089] In step (4) above, the calcined material is crushed to obtain an anode active material. The crushing is similar to disintegration, which means a process of separating the porous, aggregated secondary particles obtained after spray drying and calcination to obtain the primary particle anode active material intended in the present invention. A milling device (e.g., a jet mill) may be used for the crushing. The crushing process may affect the particle size distribution of the finally manufactured anode active material. According to one embodiment of the present invention, the crushing is performed at a grinding pressure of 0.5 bar to 3 bar, 0.5 bar to 2.5 bar, or 1 bar to 2 bar.

[0090]

[0091] <Bipolar>

[0092]

[0093] The present invention provides a positive electrode comprising the positive electrode active material described above. The positive electrode comprises a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector, and the positive electrode active material layer comprises the positive electrode active material described above. The positive electrode may be manufactured, for example, by the following method.

[0094] A composition for forming an anode active material layer comprising the aforementioned anode active material, conductive material, and binder is prepared. An anode slurry is prepared by mixing the composition with a solvent, and then the anode slurry is directly coated and dried onto an anode current collector to produce an anode electrode plate. Alternatively, the anode slurry may be cast onto a separate support, and then a film obtained by peeling off from the support is laminated onto the anode current collector to produce an anode electrode plate.

[0095] The binder used in the composition for forming the positive electrode active material layer is a component that assists in the bonding of the active material and the conductive material, as well as in the bonding to the current collector. Examples of such binders include polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber, fluororubber, and various copolymers. The content of the binder may be 1% to 30% by weight based on the total weight of the composition for forming the positive electrode active material layer. When the content of the binder is within the above range, the bonding strength of the active material layer to the current collector is good.

[0096] The conductive material used in the composition for forming the positive electrode active material layer is used to impart conductivity to the electrode, and can be used without special restrictions as long as it possesses electronic conductivity without causing chemical changes in the battery being formed. Specific examples include graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, and carbon fiber; metal powder or metal fiber such as copper, nickel, aluminum, or silver; conductive whiskey such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and one of these alone or a mixture of two or more may be used. The content of the conductive material may be 1% to 30% by weight based on the total weight of the composition for forming the positive electrode active material layer. When the content of the conductive material is within the above range, the conductivity within the active material layer is good.

[0097] When mixing the above-mentioned composition for forming the positive electrode active material layer with a solvent to form a slurry, the solvent used may include N-methylpyrrolidone (NMP), acetone, water, etc. The content of the solvent is used in an amount of 1 to 10 parts by weight based on 100 parts by weight of the composition for forming the positive electrode active material layer. When the solvent content is within the above range, the process of forming the active material layer is easy.

[0098] The positive current collector, to which the positive slurry is coated or laminated, has a thickness of about 3 μm to 500 μm and is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. For example, the positive current collector may be made of stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel with a surface treated with carbon, nickel, titanium, silver, etc. The positive current collector may also have fine irregularities formed on its surface to increase the adhesion of the positive active material, and various forms such as films, sheets, foils, nets, porous bodies, foams, and nonwoven fabrics are possible.

[0099] An anode is manufactured by directly coating and drying an anode slurry onto an anode current collector, or by laminating an anode film made of a separate film onto an anode assembly and then pressing it.

[0100]

[0101] Lithium secondary battery

[0102]

[0103] The present invention provides a lithium secondary battery comprising the anode described above. The lithium secondary battery comprises the anode described above; a cathode; a separator interposed between the anode and the cathode; and an electrolyte. Additionally, the lithium secondary battery may optionally further comprise a battery container housing an electrode assembly of the anode, cathode, and separator described above, and a sealing member sealing the battery container. The lithium secondary battery may be manufactured, for example, by the following method.

[0104] The anode and cathode are manufactured by applying and drying an anode slurry or a cathode slurry, respectively, onto a current collector. The manufacturing of the anode is as described above.

[0105] To manufacture a cathode, a cathode slurry for forming a cathode is prepared by mixing a cathode active material, a binder, a conductive material, and a solvent.

[0106] The above-mentioned cathode active material is not specifically limited to those generally used in the field, but more specifically, lithium metal, metals capable of alloying with lithium, transition metal oxides, materials capable of doping and undoping lithium, materials capable of reversibly inserting and extracting lithium ions, etc. may be used.

[0107] The above transition metal oxide may be, for example, tungsten oxide, molybdenum oxide, titanium oxide, lithium titanium oxide, vanadium oxide, lithium vanadium oxide, etc. The material capable of doping and dedoping the lithium is, for example, Si, SiO x (0<x≤2), Si-Y alloy (where Y is an alkali metal, alkaline earth metal, group 13 element, group 14 element, transition metal, rare earth element, or a combination thereof, and is not Si), Sn, SnO2, Sn-Y (where Y is an alkali metal, alkaline earth metal, group 13 element, group 14 element, transition metal, rare earth element, or a combination thereof, and is not Sn), etc., and at least one of these may be mixed with SiO2 and used. The above element Y may be Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, Se, Te, Po, or a combination thereof.

[0108] The material capable of reversibly inserting and extracting the above lithium ions is a carbon-based material, and any carbon-based negative electrode active material commonly used in lithium batteries can be used. For example, it is crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon is, for example, amorphous, plate-like, flake-like, spherical, or fibrous natural graphite; or artificial graphite, and the amorphous carbon is, for example, soft carbon (low-temperature calcined carbon) or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0109] The conductive material, binder, and solvent used in the cathode slurry may be the same as those used for the anode. In some cases, it is also possible to form pores inside the electrode plate by adding a plasticizer to the anode slurry and the cathode slurry. The content of the cathode active material, conductive material, binder, and solvent is at a level typically used in lithium secondary batteries.

[0110] The negative electrode current collector is generally made with a thickness of 3 μm to 500 μm. Such a negative electrode current collector is not particularly limited as long as it is conductive without causing chemical changes in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface treated with carbon, nickel, titanium, silver, etc., and aluminum-cadmium alloy may be used. In addition, similar to the positive electrode current collector, fine irregularities may be formed on the surface to strengthen the bonding strength of the negative electrode active material, and it may be used in various forms such as films, sheets, foils, nets, porous bodies, foams, and nonwoven fabrics.

[0111] Similar to the manufacture of the anode, the prepared cathode slurry can be directly coated and dried onto a cathode current collector to manufacture a cathode plate. Alternatively, the cathode slurry can be cast onto a separate support, and then the film obtained by peeling off from the support can be laminated onto a cathode current collector to manufacture a cathode plate.

[0112] The above-mentioned positive and negative electrodes may be separated by a separator, and any separator commonly used in lithium secondary batteries may be used. In particular, it is suitable to have low resistance to ion movement of the electrolyte and excellent electrolyte wettability. For example, it may be a material selected from glass fiber, polyester, Teflon, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), or combinations thereof, and may be in the form of a non-woven fabric or a woven fabric. The separator is used with a pore diameter of 0.01 μm to 10 μm and a thickness generally of 5 μm to 300 μm.

[0113] Lithium salt-containing non-aqueous electrolytes consist of a non-aqueous electrolyte and lithium. Non-aqueous electrolytes include non-aqueous electrolytes, solid electrolytes, and inorganic solid electrolytes.

[0114] As the above-mentioned non-aqueous electrolyte, for example, non-protic organic solvents such as N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butyl lactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphate triester, trimethoxymethane, dioxolane derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ether, methyl propionate, ethyl propionate, etc. may be used.

[0115] The above organic solid electrolyte may be, for example, a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, a polyester sulfide, a polyvinyl alcohol, polyvinylidene fluoride, a polymer containing an ionic dissociator, etc.

[0116] As the above-mentioned inorganic solid electrolyte, for example, nitrides, halides, sulfates of Li such as Li3N, LiI, Li5NI2, Li3N-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH, and Li3PO4-Li2S-SiS2 may be used.

[0117] Any lithium salt commonly used in lithium secondary batteries may be used, and as a substance that dissolves well in the above-mentioned non-aqueous electrolyte, examples include LiCl, LiBr, LiI, LiClO4, LiBF4, and LiB 10 Cl 10 One or more materials such as LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, (CF3SO2)2NLi, lithium chloroborate, lithium lower aliphatic carboxylate, and lithium 4-phenylborate may be used.

[0118] In addition to the above electrolyte components, various additives may be used in the above electrolyte for purposes such as improving battery life characteristics, suppressing battery capacity reduction, and improving battery discharge capacity.

[0119] The above additives include imide-based salts such as lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(trifluoromethylsulfonyl)imide; borate-based salts such as lithium bis(oxalate)borate (LiBOB), lithium difluoro(oxalate)borate (LiOdFB), and tris(trimethylsilyl)borate (TMSB); phosphate-based salts such as difluorophosphate and tris(trimethylsilyl)phosphate; and haloalkylene carbonate-based compounds such as difluoroethylene carbonate. Alternatively, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, triamide hexaphosphate, nitrobenzene derivative, sulfur, quinone imine dye, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, or aluminum trichloride may be included, and the above additives may be used alone or in combination. In this case, the above additives may each be included in an amount of 0.1% to 10% by weight based on the total weight of the electrolyte.

[0120] In addition to existing applications such as mobile phones and portable computers, the above-mentioned lithium secondary battery is suitable for applications requiring high capacity, high output, and high-temperature operation, such as electric vehicles, and can also be used in hybrid vehicles by combining it with existing internal combustion engines, fuel cells, and supercapacitors. Furthermore, the above-mentioned lithium secondary battery can be used in all other applications requiring high output, high voltage, and high-temperature operation.

[0121] Preferred embodiments are presented below to aid in understanding the present invention, but the following embodiments are provided only to facilitate a better understanding of the invention and do not limit the invention thereto.

[0122]

[0123] Example (Preparation of positive electrode active material)

[0124]

[0125] Example 1

[0126] Li2CO3 and FePO4 were prepared with a Li / Fe molar ratio of 1.03 and mixed with water to achieve a solid content concentration of 40 wt%. To the above raw material mixture, an amorphous carbonaceous material consisting of sucrose in an amount corresponding to 8 wt% of the solid weight and a dispersant (Manufacturer: Daejeong Hwakum, Product Name: Polyethylene Glycol 2000) in an amount corresponding to 1-2 wt% was added. The mixture was wet-milled using a bead mill to obtain an average particle size (D) of the solid content. 50 ) is 0.5㎛ or less, and the maximum particle size (D max A slurry having a particle size of 7㎛ or less was prepared. The slurry was dried using a spray drying device (inlet temperature: 200℃, outlet temperature: 80℃), and the dried powder was placed in a graphite refractory container and calcined at 800℃ for 10 hours under a nitrogen atmosphere to produce lithium iron phosphate-based compound particles in the form of secondary particles. The prepared lithium iron phosphate-based compound particles were ground using a jet mill (grind pressure: 1 bar) to obtain final lithium iron phosphate-based compound particles in the form of primary particles.

[0127]

[0128] Example 2

[0129] Final lithium iron phosphate-based compound particles in the form of primary particles were obtained by the same method as in Example 1, except that the amount of dispersant was adjusted to 1.5% by weight of the solid content.

[0130]

[0131] Example 3

[0132] Final lithium iron phosphate-based compound particles in the form of primary particles were obtained in the same manner as in Example 1, except that the amount of dispersant was adjusted to 2% by weight of the solid content.

[0133]

[0134] Example 4

[0135] Final lithium iron phosphate-based compound particles in the form of primary particles were obtained in the same manner as in Example 1, except that the amount of dispersant was adjusted to 2.25 wt% of the solid weight and the grinding pressure of the jet mill was set to 2 bar.

[0136]

[0137] Example 5

[0138] Final lithium iron phosphate-based compound particles in the form of primary particles were obtained in the same manner as in Example 1, except that the amount of dispersant was adjusted to 2.1% by weight of the solid content and the grinding pressure of the jet mill was set to 2 bar.

[0139]

[0140] Comparative Example 1

[0141] Final lithium iron phosphate-based compound particles in the form of primary particles were obtained in the same manner as in Example 1, except that the grinding pressure of the jet mill was set to 2 bar.

[0142]

[0143] Comparative Example 2

[0144] Final lithium iron phosphate-based compound particles in the form of primary particles were obtained in the same manner as in Example 1, except that the amount of dispersant was adjusted to 2% by weight of the solid content and the grinding pressure of the jet mill was set to 2 bar.

[0145]

[0146] Comparative Example 3

[0147] Final lithium iron phosphate-based compound particles in the form of primary particles were obtained in the same manner as in Example 1, except that the amount of dispersant was adjusted to 1.25 wt% of the weight of the solids and the grinding pressure of the jet mill was set to 2 bar.

[0148]

[0149] Comparative Example 4

[0150] Final lithium iron phosphate-based compound particles in the form of primary particles were obtained by the same method as in Example 1, except that the amount of dispersant was adjusted to 0.5 wt% of the weight of the solids.

[0151]

[0152] Comparative Example 5

[0153] Final lithium iron phosphate-based compound particles in the form of primary particles were obtained in the same manner as in Example 1, except that the amount of dispersant was adjusted to 1.65 wt% of the solid weight and the grinding pressure of the jet mill was set to 2 bar.

[0154]

[0155] Experimental example

[0156]

[0157] Experimental Example 1 (Evaluation of particle size of anode active material)

[0158] The particle sizes of the cathode active materials prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were measured and are shown in Table 1 below. The particle sizes were measured by PSD analysis and SEM DX analysis, respectively. The overall particle size distribution was confirmed based on the PSD analysis results, and the results are shown in Figures 1 to 10 below. In Figures 1 to 10, the x-axis represents particle size (μm), the y-axis represents the number %, and the intervals on the x-axis are displayed on a log10 scale. Additionally, the average particle size of the primary particles was confirmed based on the SEM DX analysis results. To measure the particle size, 5 mL of deionized water and 100 μL of dispersant (Triton X-100) were placed in a conical tube, and 1 mg of each cathode active material was weighed and added to the conical tube. Sonication was performed for approximately 1 minute, and the sample was poured into an analysis beaker containing 450 mL of deionized water before measurement. Specifically, for the PSD analysis, the cathode active material was introduced into a laser diffraction particle size measuring device (Manufacturer: Microtrac, Product Name: MT: 3000 II), and ultrasound of approximately 28 kHz was irradiated at an output of 60 W, after which the particle size was calculated based on the volume accumulation in the measuring device. In addition, for the SEM DX analysis, a scanning electron microscope (SEM, Manufacturer: FEI, Product Name: Inspect F) was used to obtain SEM images (×10,000 magnification), and the average particle size of the primary particles was measured using an image processing program (Manufacturer: LG Chem, Product Name: DX Program). Specifically, the boundaries of the primary particles were divided using SEM images taken at ×10,000 magnification and displayed in random colors. Then, the area of ​​each primary particle was calculated using the number of pixels corresponding to each, and the average particle size of the primary particles was calculated by dividing the total sum of the diameters by the number of particles using the diameter of a circle having the same area as each individual particle.

[0159]

[0160] PSD Analysis SEM DX Analysis D 10 (㎛)D 50 (㎛)D 90 (㎛) Average Particle Size (㎛) Example 1 0.26 80.37 80.65 80.340 Example 20.33 90.47 80.88 60.397 Example 30.26 90.37 80.65 80.378 Example 40.27 90.39 20.72 10.423 Example 50.27 50.38 10.64 10.419 Comparative Example 10.32 40.45 40.88 70.790 Comparative Example 20.26 20.36 60.618 0.205 Comparative Example 30.32 80.45 70.85 80.647 Comparative Example 40.35 10.49 50.94 20.663 Comparative Example 50.2980.4210.8160.765

[0161]

[0162] In the PSD analysis of Table 1 above, D 10 is the particle size corresponding to 10% of the volume accumulation standard, and D 50 is the particle size corresponding to 50% of the volume accumulation, and D 90 is the particle size corresponding to 90% of the volume accumulation standard. The above D 50 It is also referred to as the average particle size. In addition, in the SEM DX analysis of Table 1 above, the average particle size of the primary particles is S mean It is also written as [another spelling].

[0163] In order to derive significant technical characteristics from the above PSD analysis results and SEM DX analysis results, the following numerical values ​​were verified. Specifically, in the particle size distribution graph of the PSD analysis results, where the x-axis represents particle size (㎛) and the y-axis represents number %, the particle size is the average particle size (D 50 The fact that ) and the particle size is the volume cumulative 90% particle size (D 90 The absolute value of the slope between the points was calculated. In addition, the value of A was calculated using the following mathematical formula 1.

[0164]

[0165] [Mathematical Formula 1]

[0166] A = S mean -(D 10 +D50 ) / 2

[0167]

[0168] D used in calculating the above slope and A value 10 , D 50 , D 90 , S mean The unit used was μm. The values ​​calculated by the above-described method are shown in Table 2 below.

[0169]

[0170] y(D 50 )y(D 90 ) Slope Absolute Value A Value Example 1 15.07 3.024 3.04 0.017 Example 2 14.85 2.33 30.69 -0.0115 Example 3 15.22 2.964 3.79 0.0545 Example 4 12.80 2.373 1.70 0.0875 Example 5 13.24 2.69 40.58 0.091 Comparative Example 1 13.17 2.402 4.87 0.401 Comparative Example 2 15.13 3.89 44.60 -0.109 Comparative Example 3 13.95 2.082 9.60 0.2545 Comparative Example 4 15.17 2.782 7.72 0.240 Comparative Example 514.142.6129.190.4055

[0171]

[0172] According to Table 2 above, the cathode active materials prepared in Examples 1 to 5 have an absolute slope value of 30 to 44.5 and an A value of -0.05 to 0.2, and the characteristics regarding particle size are distinguished from the cathode active materials prepared in Comparative Examples 1 to 5.

[0173]

[0174] Experimental Example 2 (Evaluation of Battery Capacity and Resistance Characteristics)

[0175] A positive electrode slurry was prepared by mixing the respective positive electrode active materials, carbon black conductive materials, and polyvinylidene fluoride (PVdF) binders prepared in Examples 1 to 5 and Comparative Examples 1 to 5 in a weight ratio of 95:2:3 in an N-methylpyrrolidone (NMP) solvent. The prepared positive electrode slurry was applied to one surface of an aluminum current collector, dried at 100°C, and then rolled to produce a positive electrode.

[0176] An electrode assembly was manufactured by using a lithium metal electrode as the negative electrode and interposing a porous polyethylene separator between the positive and negative electrodes. This was placed inside a battery case, and a coin-type half-cell was manufactured by injecting an electrolyte solution in which 1 M lithium hexafluorophosphate (LiPF6) and 2 wt% vinyl carbonate (VC) were dissolved in an organic solvent mixed with ethylene carbonate (EC):ethyl methyl carbonate (EMC):diethyl carbonate (DEC) in a volume ratio of 1:2:1.

[0177] After manufacturing the battery, 24 hours later, it was charged at 0.1C with a constant current, and after a 30-minute rest period, discharged at 0.1C. At this time, the reference capacity of the battery was set to 150mAh / g. Through the above charging and discharging, the charging capacity, discharging capacity, efficiency, and internal resistance (DCIR) were measured, and the results are shown in Table 3 below. Here, efficiency is a % value calculated as the ratio of the discharging capacity to the charging capacity.

[0178]

[0179] Charge Capacity (mAh / g) Discharge Capacity (mAh / g) Efficiency (%) DCIR (Ω) Example 1 162.7 162.5 99.9 17.0 Example 2 164.9 164.4 99.7 15.7 Example 3 162.3 162.1 99.9 16.3 Example 4 162.2 161.1 99.3 16.8 Example 5 162.9 162.2 99.5 17.8 Comparative Example 1 161.1 154.2 95.7 20.6 Comparative Example 2 163.7 161.4 98.6 20.5 Comparative Example 3 163.3 158.7 97.2 20.4 Comparative Example 4 165.7 160.1 96.6 23.4 Comparative Example 5161.2155.296.320.4

[0180]

[0181] According to Table 3 above, when the cathode active materials prepared in Examples 1 to 5 were applied to a battery, the charge capacity and discharge capacity were found to be high at 161 mAh / g or higher, and the efficiency was also found to be high at 99.3% or higher. Furthermore, the internal resistance was also found to be low at 18 Ω or lower, confirming that the electrochemical performance was improved due to the characteristics of the particle size of the cathode active materials described above.

[0182]

[0183] All simple variations or modifications of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be clarified by the appended claims.

Claims

1. As a positive electrode active material comprising lithium iron phosphate-based compound particles, In the PSD analysis results, for the above lithium iron phosphate-based compound particles, in a particle size distribution graph where the x-axis represents particle size (㎛) and the y-axis represents number %, the particle size is the average particle size (D 50 The fact that ) and the particle size is the volume cumulative 90% particle size (D 90 A positive electrode active material for a lithium secondary battery having an absolute value of the slope between points of ) from 30 to 44.

5.

2. In Claim 1, The above lithium iron phosphate-based compound particles have an average particle size (D) in the PSD analysis results. 50 A positive electrode active material for a lithium secondary battery characterized by having a thickness of 0.2㎛ to 0.6㎛.

3. In Claim 1, The above lithium iron phosphate-based compound particles have a volume cumulative 10% particle size (D) in the PSD analysis results. 10 A positive electrode active material for a lithium secondary battery characterized by having a thickness of 0.15㎛ to 0.45㎛.

4. In Claim 1, The above lithium iron phosphate-based compound particles have a volume cumulative 90% particle size (D) in the PSD analysis results. 90 A positive electrode active material for a lithium secondary battery characterized by having a thickness of 0.5㎛ to 1.0㎛.

5. In Claim 1, The above lithium iron phosphate-based compound particles have a single peak in the particle size distribution graph in the PSD analysis results, where the x-axis is particle size (㎛) and the y-axis is number %, The above particle size distribution graph has an asymmetric shape centered around a peak, and The particle size at the above peak is the 90% volume cumulative particle size (D 90 10% of the volume accumulation particle size (D) compared to ) 10 A positive electrode active material for a lithium secondary battery characterized by being close to ).

6. In Claim 1, A positive electrode active material for a lithium secondary battery, characterized in that the lithium iron phosphate-based compound particles have an A value of -0.05 to 0.2 obtained from the following mathematical formula 1: [Mathematical Formula 1] A = S mean -(D 10 +D 50 ) / 2 Here, S mean ε is the average particle size (μm) of the primary particles in the SEM DX analysis results, and D 10 is the 10% volume cumulative particle size (㎛) in the PSD analysis results, and D 50 is the average particle size (㎛) in the PSD analysis results.

7. In Claim 1, A positive electrode active material for a lithium secondary battery characterized by the above lithium iron phosphate-based compound being represented by the following chemical formula 1: [Chemical Formula 1] Li 1+a Fe 1-x-y Mn x M y PO4 In the above chemical formula 1, M is at least one element selected from the group consisting of V, Al, Ni, Co, Mg, Nb, Mo, W, Ti, Sr, Zr, B, Y and Zn, and -0.1≤a≤0.1, 0≤x≤0.7, 0≤y≤0.

1.

8. A method for manufacturing an anode active material comprising lithium iron phosphate-based compound particles, wherein In the PSD analysis results, for the above lithium iron phosphate-based compound particles, in a particle size distribution graph where the x-axis represents particle size (㎛) and the y-axis represents number %, the particle size is the average particle size (D 50 The fact that ) and the particle size is the volume cumulative 90% particle size (D 90 The absolute value of the slope between the points is 30 to 44.5, and The above manufacturing method is, (1) A step of mixing a raw material of a lithium iron phosphate compound, a carbon-based material, and a dispersant in a solvent; (2) A step of spray-drying the mixture; (3) Step of firing the dried material; and (4) A method for manufacturing a positive electrode active material for a lithium secondary battery, comprising the step of grinding the calcined material.

9. In Claim 8, A method for manufacturing a positive electrode active material for a lithium secondary battery, characterized in that, in step (1) above, a carbon-based material is mixed in an amount of 1 to 15 parts by weight based on 100 parts by weight of solids in the mixture.

10. In Claim 8, A method for manufacturing a positive electrode active material for a lithium secondary battery, characterized in that, in step (1) above, the dispersant is mixed in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of solids in the mixture.

11. In Claim 8, The above (2) step further includes a step of grinding the mixture before the above step, and Average particle size of solids in the mixture (D) by the above grinding 50 ) is 0.5㎛ or less, and the maximum particle size of the solid content (D max A method for manufacturing a positive electrode active material for a lithium secondary battery, characterized in that the thickness is controlled to 7㎛ or less.

12. In claim 8, A method for manufacturing a positive electrode active material for a lithium secondary battery, characterized in that the spray drying in step (2) above is performed at a temperature of 80°C to 250°C.

13. In claim 8, A method for manufacturing a positive electrode active material for a lithium secondary battery, characterized in that, in step (3) above, the calcination is performed at 700°C to 900°C for 5 to 15 hours.

14. In Claim 8, A method for manufacturing a positive electrode active material for a lithium secondary battery, characterized in that in step (4) above, grinding is performed at a grinding pressure of 0.5 bar to 3 bar.

15. Anode comprising the anode active material according to Claim 1.

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