KR20240026364A - Anode active material for lithium secondary battery and method of manufacturing thereof - Google Patents

Abstract

This embodiment relates to a negative electrode active material and a method of manufacturing the same. The negative electrode active material is a graphite material containing secondary particles, the secondary particles are assembled from a plurality of primary particles, and the graphite material is subjected to X-ray diffraction. The 002 plane spacing (d ₀₀₂ ) according to the analysis is 0.3354 to 0.3362 ㎚, and can satisfy the following equation 1.
<Equation 1>
^1.2 ≤ Span -means D10)/D50)

Description

Negative active material for lithium secondary battery, manufacturing method thereof, and lithium secondary battery comprising the same {ANODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY AND METHOD OF MANUFACTURING THEREOF}

These embodiments relate to secondary batteries, and more specifically, to negative electrode active materials for lithium secondary batteries, and methods of manufacturing the same.

A lithium secondary battery generally consists of a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a separator, and an electrolyte, and charging and discharging are performed by intercalation-decalation of lithium ions. The lithium secondary battery is charged and discharged based on energy density. The lithium secondary battery has the advantages of high energy density, large electromotive force, and high capacity, so it is applied in various fields.

In addition, improving high-temperature performance such as high-temperature storage characteristics and high-temperature cycling characteristics in lithium secondary batteries is an important problem to be solved. For example, after applying and rolling the negative electrode active material to the current collector, if the total internal pore volume is high, there is a high possibility that the high temperature performance of the negative electrode will deteriorate. Therefore, there is a need to improve high-temperature characteristics when developing anode materials for lithium secondary batteries, for example, secondary batteries for rapid charging, by minimizing changes in electrode structure and total internal pore volume that occur during electrode rolling.

In addition, as technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing. Among secondary batteries, lithium secondary batteries exhibit high energy density and operating potential, long cycle life, and low self-discharge rate. Batteries have been commercialized and are widely used.

In addition, as interest in environmental issues grows, interest in electric vehicles and hybrid electric vehicles that can replace vehicles that use fossil fuels such as gasoline vehicles and diesel vehicles, which are one of the main causes of air pollution, is increasing. , research is being actively conducted to use lithium secondary batteries as a power source for the electric vehicles and hybrid electric vehicles.

Recently, due to the rapid rise of EV electric vehicles, expectations for lithium secondary batteries are growing, and demands for preserving existing capacity and improving fast charging characteristics are increasing. The role of the negative electrode active material, which is responsible for storing lithium ions during charging, is becoming more important in improving the rapid charging.

As the negative electrode active material, materials such as metallic lithium negative electrode active material, carbon-based negative electrode active material, or silicon oxide (SiOX) are used. The carbon-based negative active material exhibits excellent capacity preservation characteristics and efficiency. Since the carbon-based negative electrode active material used as the negative electrode of a lithium secondary battery has a potential close to the electrode potential of lithium metal, the change in crystal structure is small during the insertion and desorption process of ionic lithium. In addition, the carbon-based negative active material enables continuous and repetitive oxidation and reduction reactions in the electrode, allowing lithium secondary batteries to exhibit high capacity and excellent lifespan.

Various types of materials are used as the carbon-based negative electrode active material, such as natural graphite and artificial graphite, which are crystalline carbon-based materials, or hard carbon and soft carbon, which are amorphous carbon-based materials. Among the carbon-based negative electrode active materials, graphite-based negative electrode active materials, which have excellent reversibility and can improve the lifespan characteristics of lithium secondary batteries, are the most widely used.

Since the graphite-based negative electrode active material has a low discharge voltage of -0.2 V compared to lithium, batteries using the graphite-based negative electrode active material can exhibit a high discharge voltage of 3.6 V, which has an excellent advantage in terms of energy density of lithium secondary batteries.

Artificial graphite, which is a crystalline carbon-based material, creates a graphite crystal structure by applying high heat energy of 2,700°C or more, so it has a more stable crystal structure than natural graphite, so the change in crystal structure is small even after repeated charging and discharging of lithium ions, so it has a relatively long lifespan. This is long. In general, artificial graphite-based anode active materials have the advantage of having a lifespan that is 2 to 3 times longer than natural graphite.

Soft carbon and hard carbon, which are amorphous carbon-based materials whose crystal structure is not stabilized, have characteristics that allow lithium ions to advance more smoothly and can increase charging and discharging speeds, so they can be used in electrodes that require high-speed charging. Therefore, in consideration of the lifespan characteristics and output characteristics of the lithium secondary battery to be used, it is common to mix the carbon-based materials in a certain ratio.

Additionally, in lithium secondary batteries, improving high-temperature performance such as high-temperature storage characteristics and high-temperature cycling characteristics is an important problem to be solved. After applying the negative electrode active material to the current collector and rolling it, if the total internal pore volume is high, there is a high possibility that the high temperature performance of the negative electrode will deteriorate. Therefore, there is a need to improve the high-temperature characteristics of lithium secondary batteries by minimizing changes in electrode structure and total internal pore volume that occur during electrode rolling.

The technical problem to be solved by the present invention is to provide a negative electrode active material that can realize electrode density according to powder resistance characteristics and exhibit high electrochemical properties.

Another technical problem to be solved by the present invention is to provide a negative electrode active material having the above advantages by performing a central assembly process using two or more rotating axes through pressure extrusion or pressure/expansion and graphitization treatment.

According to an embodiment of the present invention, the negative electrode active material is a graphite material containing secondary particles, wherein the secondary particles are assembled from a plurality of primary particles, and the graphite material has a plane spacing of 002 according to X-ray diffraction analysis. (d ₀₀₂ ) is 0.3354 to 0.3362 nm, and can satisfy the following equation 1.

<Equation 1>

1.2 ≤ Span × (specific surface area (BET) [m ² /g]/tap density [g/cc]) ≤ 1.72

(The Span value means (D90-D10)/D50, which is the ratio of the difference between the D90 particle size and D10 particle size to the D50 particle size of the graphite material.)

In one embodiment, the negative electrode active material may satisfy Equation 2 below.

<Equation 2>

3.95 ≤ Sphericity/Span value ≤ 4.80

(The Span value means (D90-D10)/D50, which is the ratio of the difference between the D90 particle size and D10 particle size to the D50 particle size of the graphite material.)

In one embodiment, the negative electrode active material may satisfy Equation 3 below.

<Equation 3>

0.310 ≤ 002 Surface spacing (d ₀₀₂ )/Tap density ≤ 0.400

In one embodiment, the negative electrode active material may have a sphericity degree of 0.85 to 1.0. In one embodiment, the Span value ((D90-D10)/D50), which is the ratio of the difference between the D90 particle size and the D10 particle size with respect to the D50 particle size of the graphite material, may be 1.4 or less.

In one embodiment, the negative electrode active material may have a tap density of 0.8 g/cc or more. In one embodiment, the negative electrode active material may have a specific surface area (BET) of 1.3 g/m ² or less. In one embodiment, the electrical conductivity measured by powder resistance measurement at a load of 600 to 1000 kgf may be 38 to 121 S/cm.

In one embodiment, the density as measured by powder resistance at a load of 600 to 1000 kgf may be 1.45 to 1.80 g/cc. In one embodiment, the primary particles may be graphitized from at least one of coal-based coke and petroleum-based coke.

According to another embodiment of the present invention, a method for producing a negative electrode active material includes providing primary particles from a carbon raw material, mixing the primary particles and a binder at room temperature for more than 30 minutes, and mixing the primary particles and Inserting the binder into a granulator, assembling the primary particles and the binder introduced into the granulator to produce secondary particles, and graphitizing the assembled secondary particles at 2,700° C. or higher. , the content of the binder with respect to 100 parts by weight of the primary particles may be 10.0 to 13.5 parts by weight. In one embodiment, the step of providing primary particles from a carbon raw material includes grinding the carbon raw material, and the primary particles have D10: 5 to 10 ㎛, D50: 10 to 18 ㎛, and D90: 20. At least one of 28 ㎛ may be satisfied.

In one embodiment, the step of manufacturing secondary particles by assembling the primary particles and the binder introduced into the granulator may include assembling at 30 RPM or more. In one embodiment, the step of manufacturing secondary particles by assembling the primary particles and the binder introduced into the granulator may include assembling the granulated powder through pressurization at 100 ° C. or higher.

According to an embodiment of the present invention, by controlling the particle size of coke, it is possible to implement electrode density according to powder resistance characteristics and provide a negative electrode active material with excellent electrochemical properties.

Additionally, according to another embodiment of the present invention, a method for manufacturing a negative electrode active material having the above advantages can be provided.

1A and 1B are SEM photographs of a negative electrode active material according to an embodiment of the present invention.
Figure 2 is a graph of electrode density according to powder resistance, according to an embodiment of the present invention.

Terms such as first, second, and third are used to describe, but are not limited to, various parts, components, regions, layers, and/or sections. These terms are used only to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, the first part, component, region, layer or section described below may be referred to as the second part, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is only intended to refer to specific embodiments and is not intended to limit the invention. As used herein, singular forms include plural forms unless phrases clearly indicate the contrary. As used in the specification, the meaning of "comprising" refers to specifying a particular characteristic, area, integer, step, operation, element and/or ingredient, and the presence or presence of another characteristic, area, integer, step, operation, element and/or ingredient. This does not exclude addition.

When a part is referred to as being “on” or “on” another part, it may be directly on or on the other part or may be accompanied by another part in between. In contrast, when a part is said to be "directly on top" of another part, there is no intervening part between them.

Although not defined differently, all terms including technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries are further interpreted as having meanings consistent with related technical literature and currently disclosed content, and are not interpreted in ideal or very formal meanings unless defined.

Hereinafter, in this specification, “green coke (raw coke)” generally means manufacturing pitch, which is coal or petroleum residue or processed product, through a coking reaction under high pressure and high temperature conditions. Specifically, depending on the composition of the raw materials and coking process conditions, anisotropic or needle coke with a high degree of carbonaceous structure orientation in the uniaxial direction or isotropic or pitch coke with a low degree of carbonaceous structure orientation. is obtained. More specifically, “green” refers to a state obtained immediately after the coking process and containing a certain percentage of volatile matter without undergoing heat treatment such as calcination or carbonization.

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, and the present invention is not limited thereby, and the present invention is only defined by the scope of the claims to be described later.

According to an embodiment of the present invention, the negative electrode active material is a graphite material containing secondary particles, and the secondary particles are assembled from a plurality of primary particles. The secondary particles may be assembled by agglomerating a plurality of primary particles and then graphitizing them in a manufacturing method step described later. Specifically, the primary particle refers to a particle that becomes a component when another particle is formed from one particle, and a plurality of primary particles can be aggregated, combined, or aggregated to form secondary particles. there is. In the present invention, a plurality of the primary particles may be aggregated to form secondary particles.

In one embodiment, the negative electrode active material may satisfy Equation 1 below.

<Equation 1>

1.2 ≤ Span × (specific surface area (BET) [m ² /g]/tap density [g/cc]) ≤ 1.72

The Span value means (D90-D10)/D50, which is the ratio of the difference between the D90 particle size and the D10 particle size to the D50 particle size of the graphite material. Specifically, the Span value refers to a value obtained by using the calculation formula of (D90-D10)/D50 using D10, D50, and D90, which are indicators of particle size. More specifically, the D10, D50, and D90 particle sizes refer to the particle sizes when active material particles of various particle sizes are accumulated to 10%, 50%, and 90% by volume, respectively.

Equation 1 above can satisfy the range of 1.2 to 1.72. Specifically, Equation 1 above may satisfy the range of 1.4 to 1.70. By satisfying Equation 1 above, there is an advantage in that electrode processability is excellent.

If the value of Equation 1 is outside the upper limit, there is a problem in that it is not easy to improve electrode density because the span value and specific surface area are large. If the value of Equation 1 is outside the lower limit, there is an uneconomical problem due to excessive cost.

In one embodiment, the negative electrode active material may have a specific surface area (BET) of 1.3 g/m ² or less. In one embodiment, the tap density may be greater than 0.8 g/cc. In the case of a negative electrode active material containing graphite, the smaller the specific surface area and the larger the tap density, the better the battery characteristics when applied to a lithium secondary battery.

In one embodiment, the Span value may be 1.40 or less. Specifically, the Span value may be 1.30 or less. More specifically, the Span value may range from 1.10 to 1.30, and more specifically, from 1.23 to 1.30.

If the Span value is outside the upper limit of the above range, the total specific surface area increases due to fine powder, which reduces the initial charge and discharge efficiency, and the viscosity of the slurry for electrode coating increases significantly, making it difficult to manufacture electrodes of uniform quality. there is a problem. If the Span value is outside the lower limit of the above range, the production yield may be significantly reduced and the cost may increase in order to industrially process powders with very small particle size deviations. In addition, the porosity between powders is relatively low, which reduces the wettability of the electrolyte, which reduces ionic conductivity within the electrode and makes it difficult to implement an electrode with a high tap density.

In one embodiment, D10 of the active material may satisfy the range of 9 to 12 ㎛. In one embodiment, the D50 of the active material may satisfy the range of 11 to 20 ㎛. Specifically, the D50 of the active material may satisfy the range of 13 to 16 ㎛. In one embodiment, the D90 of the active material may satisfy the range of 20 to 33 ㎛. Specifically, the D90 of the active material may satisfy the range of 25 to 30 ㎛.

In one embodiment, the negative electrode active material may satisfy Equation 2 below.

<Equation 2>

3.95 ≤ Sphericity/Span value ≤ 4.80

Equation 2 above can satisfy the range of 3.95 to 4.80. Specifically, Equation 2 may satisfy the range of 3.958 to 4.765. By satisfying Equation 2 above, there is an advantage in that electrode processability is increased and side reaction sites are reduced due to a high degree of spheroidization, resulting in high efficiency and output.

If the value of Equation 2 is outside the upper limit, there is an uneconomical problem. If the value of Equation 2 exceeds the lower limit, there is a problem that output and efficiency decrease due to an increase in side reaction sites, and electrode processability decreases, leading to a decrease in electrode density.

In one embodiment, the negative electrode active material may satisfy Equation 3 below.

<Equation 3>

0.310 ≤ (002) Plane spacing (d ₀₀₂ )[nm]/tap density [g/cc] ≤ 0.400

Equation 3 above can satisfy the range of 0.310 to 0.400. If the value of Equation 3 is outside the upper limit, electrode processability is lowered, function is deteriorated when applying anode material, and capacity and efficiency are deteriorated. If the value of Equation 3 is outside the lower limit, there is an uneconomical problem.

The (002) interplanar spacing (d ₀₀₂ ) is measured by powder state X-ray diffraction analysis of the negative electrode active material, and refers to the interplanar spacing of graphite. Specifically, the interplanar spacing may refer to the distance between (002) crystal planes that are parallel to each other. Depending on the surface spacing, the extent to which lithium ions are inserted and desorbed may vary, and accordingly, the capacity of the graphite may also vary.

In one embodiment, the graphite material may have a (002) interplane spacing (d ₀₀₂ ) of 0.3354 to 0.3362 nm according to X-ray diffraction analysis. Specifically, the graphite material may have a (002) interplane spacing (d ₀₀₂ ) of 0.3358 to 0.3360 nm. Since the interplanar spacing (d ₀₀₂ ) satisfies the above range, a space can be secured for lithium ions to easily insert and desorb between the (002) crystal planes of the graphite material, so the lithium ions have a small diffusion resistance, thereby Insertion and desorption of ions can occur freely.

If the surface spacing exceeds the upper limit, the capacity of the active material is small, so the thickness of the negative electrode becomes thick in order to manufacture a secondary battery containing it with high capacity, and there is a problem that the lifespan characteristics are lowered and the efficiency is greatly reduced. When the interplanar spacing exceeds the lower limit, it is difficult for lithium ions to be inserted and desorbed into the interplanar spacing, so diffusion resistance increases and lithium precipitation occurs during high-rate charging and discharging, which may deteriorate lifespan characteristics.

In one embodiment, the negative electrode active material may satisfy Equation 4 below.

<Equation 4>

1.10 ≤ specific surface area (BET) [m ² /g]/tap density [g/cc] ≤ 1.65

Equation 4 above can satisfy the range of 1.10 to 1.65. Specifically, Equation 4 may satisfy the range of 1.18 to 1.45. By satisfying Equation 4 above, there is an advantage in that electrode processability and capacity are excellent.

If it exceeds the upper limit of Equation 4 above, the specific surface area is large and there is a problem of reduced capacity and efficiency due to an increase in side reaction sites. If it exceeds the lower limit of Equation 4 above, there is an uneconomical problem.

In one embodiment, the secondary particles may have a degree of sphericity of 0.85 to 1.0 based on the particle diameter. Specifically, the degree of sphericity may be 0.85 to 0.95. The closer the sphericity degree is to 1, the higher the tap density is and the fewer side reaction sites, so the closer the sphericity degree is to 1, the better.

In one embodiment, the negative electrode active material may have an electrical conductivity of 38 to 152 S/cm as measured by powder resistance under a load of 600 to 1000 kgf. Specifically, the electrical conductivity may be 55 to 120 S/cm. By satisfying the electrical conductivity range in the above load range, the development of the carbon crystal structure is sufficiently developed, crystallinity increases, and the carbon itself electrical conductivity improves, thereby suppressing the increase in resistance due to current leakage during charging and discharging. There is an advantage in terms of capacity maintenance rate.

If the electrical conductivity measured by powder resistance in the above load range exceeds the upper limit, there is an uneconomical problem. If the electrical conductivity exceeds the lower limit, there is a problem of low capacity and efficiency.

In one embodiment, the negative electrode active material may have an electrode density of 1.45 to 1.80 g/cc as measured by powder resistance measurement at a load of 600 to 1000 kgf. Specifically, the electrode density may be 1.50 to 1.65 g/cc. When the density measured by powder resistance measurement in the above load range satisfies the above range, there is an advantage that the carbon's own electrical conductivity is improved and the capacity retention rate is high.

A method of manufacturing a negative electrode active material according to another embodiment of the present invention includes providing primary particles from a carbon raw material, introducing the primary particles and the binder into a granulator, and assembling the primary particles and the binder introduced into the granulator. It includes preparing secondary particles, and graphitizing the assembled secondary particles at 2,700°C or higher.

In the step of providing primary particles from the carbon raw material, the carbon raw material may be green coke or calcined coke. Specifically, when green coke is used among the carbon raw materials, it is possible to provide a negative electrode active material for a lithium secondary battery with a low expansion rate and excellent fast charging and discharging characteristics. In one embodiment, the carbon raw material may be a coke mixture that is isotropic, anisotropic, or a combination thereof, for example, needle coke.

In one embodiment, providing primary particles from the carbon raw material may include grinding the carbon raw material. The carbon raw material is, for example, a grinder such as a Jet-mill, Roller-mill, or a general continuous or batch type that can perform air classification at the same time as grinding. A pulverizer of the type can be used. However, this is a non-limiting example, and various grinding devices may be used.

In one embodiment, the step of pulverizing the carbon raw material may be performed so that the primary particles have a particle size D10 of 5 to 10 ㎛, specifically, 7 to 9 ㎛. In the step of pulverizing the carbon raw material, the primary particles may be pulverized so that the particle size D50 is 10 to 18 ㎛, specifically 10 to 15 ㎛, and more specifically 10 to 13 ㎛. In the step of pulverizing the carbon raw material, the primary particles may be pulverized so that the particle size D90 is 20 to 28 ㎛, specifically, the primary particle particle size D90 is 20 to 25 ㎛.

If the particle sizes of D10, D50, and D90 are lower than the lower limit of the above-mentioned range, it corresponds to fine powder, and there is a problem of reduced battery life due to reduced capacity/efficiency. When the D10, D50, and D90 particle sizes are higher than the upper limit of the above-mentioned range, there is a problem that the output decreases.

In one embodiment, the Span value of the primary particle may be 1.20 to 1.8. Specifically, the Span value may be 1.23 to 1.6. By satisfying the particle size and Span value of the primary particles, the active material after carbonization can be controlled to the target particle size, thereby satisfying the above-mentioned equations 1 to 5, and improving battery characteristics when applied to batteries. There is an advantage.

Before introducing the primary particles and the binder into the granulator, the step of mixing the primary particles and the binder at room temperature may be further included. The primary particles and the binder may be directly introduced into a granulator composed of a two-axis or more rotating body without prior mixing, or may be mixed in advance and then added.

In one embodiment, mixing the primary particles and the binder at room temperature may be performed for 30 minutes or more. Specifically, the mixing step at room temperature may be performed within 30 minutes to 240 minutes. The mixing step at room temperature refers to the time for maintaining the mixed primary particles and the binder after reaching the kneading temperature.

If the mixing step is performed for a time lower than the lower limit of the time, there is a problem in that the primary particles and the binder are not properly mixed, and the mixing step is performed for a time higher than the upper limit of the time. If this happens, there is a problem that the binder volatilizes and the adhesive performance deteriorates.

In one embodiment, the step of mixing the primary particles and the binder at room temperature may be performed using a Hensel mixer, V-mixer, or a combination thereof.

For example, the assembler may include a rotating body of two or more axes, where the rotating body rotates and the particles are assembled. In one embodiment, the granulator may be, for example, a continuous twin-screw granulator. The continuous twin-screw granulator can obtain assembled products in a molded form through compression/expansion, rather than coating particles using existing air currents. It tends to be assembled at a higher density, and the closed internal rotation method can generate frictional heat of more than 200 ℃ through friction between particles. This has the advantage of simplifying the process because, when using coal-based pitch with a low softening point, secondary particles can be assembled without a separate carbonization process. The continuous twin-screw granulator is a non-limiting example, and is not limited as long as it assembles particles through physical pressure. In this way, by using two or more rotating axes through the central assembly process through pressure extrusion or pressure and expansion, it is possible to manufacture a negative electrode active material that has excellent powder resistance properties and exhibits high electrochemical properties. .

In the step of manufacturing secondary particles by assembling the primary particles and binder introduced into the granulator, the binder may be, for example, pitch with a softening point of 200° C. or lower. Specifically, the binder may be a material based on coal-based raw materials such as coal tar or petroleum-based raw materials.

Specifically, the softening point may be 80 to 200°C, more specifically, 80 to 120°C. If the softening point of the binder is excessively high, the operating temperature of the equipment for melting the binder material is high, which increases equipment manufacturing costs and may cause thermal denaturation and carbonization of some samples due to use at high temperatures. If the softening point of the binder is excessively low, the binding force may be low, making it difficult to smoothly bond between primary particles and form secondary particles, making it difficult to implement an economical manufacturing process due to low carbonization yield.

The step of assembling the primary particles and binder introduced into the granulator to produce secondary particles may include adding 9.5 to 13.8 parts by weight of the binder based on 100 parts by weight of the primary particles. Specifically, it may include adding 10.0 to 14.0 parts by weight of the binder based on 100 parts by weight of the primary particles.

If the binder content is excessively high, the capacity of the anode material may be reduced due to a relatively high content of graphite derived from the binder. In addition, there is a problem that the specific surface area is increased due to the high pore content generated during thermal decomposition, which may reduce battery efficiency. If the content of the binder is excessively small, the binding effect may be small and secondary particles may not be formed smoothly. In addition, the cohesion between primary particles within secondary particles is reduced, which may cause the powder to easily become finely divided during powder processing processes such as grinding.

The step of graphitizing the assembled secondary particles at 3,000°C or higher may be performed at a temperature of 3.000°C to 3,500°C. Specifically, it may be performed in the temperature range of 3,200°C to 3,500°C. By processing the assembled secondary particles at 3,000° C. or higher, the degree of graphitization increases, thereby increasing capacity.

If the graphitizing step is outside the upper limit of the temperature range, there is an uneconomical problem. If the graphitizing step is outside the lower limit of the temperature range, there is a problem that the degree of graphitization decreases and the capacity decreases.

In one embodiment, the step of grinding the graphitized particles may be further included. Specifically, a grinding process may be performed after carbonization to reduce surface roughness and exposure of fractured surfaces and to form spherical particles. Through the grinding process, the degree of sphericity can be increased and the tap density of the graphite material can be improved.

In one embodiment, the step of manufacturing secondary particles by assembling the primary particles and the binder introduced into the granulator may include assembling at 30 RPM (Revolutions per Minute) or more.

In one embodiment, the step of manufacturing secondary particles by assembling the primary particles and the binder introduced into the granulator may include assembling the granulated powder through pressurization at 100° C. or higher.

According to another embodiment of the present invention, a lithium secondary battery may include a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, and a separator and electrolyte solution positioned between the positive electrode and the negative electrode.

_The anode is LiCoO ₂ , LiNiO ₂ , LiNi _{x Mn y O 2 , Li 1+z} Ni _x Mn _{y Co 1-xy O 2 ,} LiNi , LiMnO ₂ , LiCrO ₂ , LiMn ₂ O ₄ , LiFeO ₂ , LiFePO ₄ , and combinations thereof, where x is 0.3 to 0.8, y is 0.1 to 0.45, and z is independently It may be 0 to 0.2. More specifically, the anode may be LiFePO ₄ , LiCoO ₂ , NCM811, and NCM622.

The negative electrode may use a negative electrode active material manufactured using the negative electrode active material precursor, a negative electrode active material, or a negative electrode active material precursor prepared through the negative electrode active material precursor manufacturing method described above.

The separation membrane is a conventional porous polymer film used as a separator, such as ethylene homopolymer, propylene homopolymer, ethylene/propylene copolymer, ethylene/butene copolymer, ethylene/hexene copolymer, and ethylene/methacrylate copolymer. Porous polymer films made of polyolefin-based polymers, such as polymers, can be used alone or by laminating them, or conventional porous non-woven fabrics, such as high-melting point glass fibers, polyethylene terephthalate fibers, etc., can be used. , this is a non-limiting example.

In the electrolyte solution, the lithium salt that can be included as the electrolyte may be those commonly used in electrolyte solutions for lithium secondary batteries without limitation. For example, the anions of the lithium salt include F ^- , Cl ^- , Br ^- , I ^- , NO ₃ ^- , N(CN) ₂ ^- , BF ₄ ^- , ClO ₄ ^- , PF ₆ ^- , (CF ₃ ) ₂ PF ₄ ^- , (CF ₃ ) ₃ PF ₃ ^- , (CF ₃ ) ₄ PF ₂ ^- , (CF ₃ ) ₅ PF ^- , (CF ₃ ) ₆ P ^- , CF ₃ SO ₃ ^- , CF ₃ CF ₂ SO ₃ ^- , (CF ₃ SO ₂ ) ₂ N ^- , (FSO ₂ ) ₂ N ^- , CF ₃ CF ₂ (CF ₃ ) ₂ CO ^- , (CF ₃ SO ₂ ) ₂ CH ^- , (SF ₅ ) ₃ C ^- , (CF ₃ SO ₂ ) ₃ C ^- , CF ₃ (CF ₂ ) ₇ SO ₃ ^- , It may be any one selected from the group consisting of CF ₃ CO ₂ ^- , CH ₃ CO ₂ ^- , SCN ^- and (CF ₃ CF ₂ SO ₂ ) ₂ N ^- .

In the electrolyte solution, organic solvents commonly used in electrolytes for lithium secondary batteries can be used without limitation, and representative examples include propylene carbonate (PC), ethylene carbonate (EC), and Ethyl carbonate (DEC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), methylpropyl carbonate, dipropyl carbonate, dimethyl sulfuroxide, acetonitrile, dimethoxyethane, diethoxyethane, vinylene Any one selected from the group consisting of carbonate, sulfolane, gamma-butyrolactone, propylene sulfite, and tetrahydrofuran, or a mixture of two or more of these, can be typically used.

The lithium secondary battery may be placed in a battery case. The battery case is a non-limiting example and may be any one of a cylindrical shape using a can, a rectangular shape, a pouch type, and a coin type.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

<Anode active material>

How to measure sphericity

The degree of sphericity was measured using a particle shape analyzer (Particle Imange Analyzer, Model: FlowCAM 8100-B). The closer the sphericity degree is to 1, the closer the shape is to a smooth sphere, and the closer the negative electrode material is to a sphere, the higher the tap density is and the fewer side reaction sites, which is preferable.

Particle size measurement method

The particle size of coke as a base material was classified using Cilas 1090 equipment.

How to measure tap density

Based on ASTM-B527, 20 g of powder was placed in a 50 mL container, and then the packing density was measured by tapping left, right, up and down at 3000 cycle @ 284 cycle/min.

Specific surface area measurement method

The specific surface area was measured using the BET method (Surface area and Porosity analyzer) (Micromeritics, ASAP2020).

Surface spacing (d002) measurement method

Based on the XRD data, the X-ray wavelength, peak intensity, and reference peak intensity were calculated based on the peak at 26.5 degrees.

<Experimental Example 1>

Petroleum-based needle coke (D10: 8 ㎛, D50: 12 ㎛, D90: 24 ㎛) with a sphericity degree of 0.85 and a controlled particle size was mixed with coal-based pitch with a softening point of 90°C at room temperature at a ratio of 1:0.10. The room temperature mixing was performed using Kurimoto Sigma-blade type kneader 2Liter scale equipment.

Afterwards, the mixture was kneaded at a temperature of 100°C for 1 hour, cooled naturally, and then discharged at 80°C. Thereafter, the discharged mixture was graphitized at 3,200°C for more than 5 hours to prepare a negative electrode active material.

<Experimental Example 2>

Petroleum-based needle coke (D10: 8 ㎛, D50: 12 ㎛, D90: 24 ㎛) with a sphericity degree of 0.85 and a controlled particle size was mixed with coal-based pitch with a softening point of 90°C at room temperature at a ratio of 1:0.13. The room temperature mixing was performed using Kurimoto Sigma-blade type kneader 2Liter scale equipment.

Afterwards, the mixture was kneaded at a temperature of 100°C for 2 hours, cooled naturally, and then discharged at 80°C. Thereafter, the discharged mixture was graphitized at 3,200°C for more than 5 hours to prepare a negative electrode active material.

<Experimental Example 3>

Coal-based needle coke (D10: 7 ㎛, D50: 10 ㎛, D90: 23 ㎛) with a sphericity degree of 0.93 and particle size adjusted was mixed with Coal-based pitch with a softening point of 90°C at room temperature at a ratio of 1:0.10. The room temperature mixing was performed using Kurimoto Sigma-blade type kneader 2Liter scale equipment.

Afterwards, the mixture was kneaded at a temperature of 100°C for 1 hour, cooled naturally, and then discharged at 80°C. Thereafter, the discharged mixture was graphitized at 3,200°C for more than 5 hours to prepare a negative electrode active material.

<Experimental Example 4>

Coal-based needle coke (D10: 7 ㎛, D50: 10 ㎛, D90: 23 ㎛) with a sphericity degree of 0.93 and particle size adjusted was mixed with Coal-based pitch with a softening point of 90°C at room temperature at a ratio of 1:0.13. The room temperature mixing was performed using Kurimoto Sigma-blade type kneader 2Liter scale equipment.

Afterwards, the mixture was kneaded at a temperature of 100°C for 2 hours, cooled naturally, and then discharged at 80°C. Thereafter, the discharged mixture was graphitized at 3,200°C for more than 5 hours to prepare a negative electrode active material.

<Experimental Example 5>

Coal-based needle coke (D10: 7 ㎛, D50: 10 ㎛, D90: 23 ㎛) with a sphericity degree of 0.92 and particle size adjusted was mixed with Coal-based pitch with a softening point of 90°C at room temperature at a ratio of 1:0.13. The room temperature mixing was performed using Kurimoto Sigma-blade type kneader 2Liter scale equipment.

Afterwards, the mixture was kneaded at a temperature of 100°C for 2 hours, cooled naturally, and then discharged at 80°C. Thereafter, the discharged mixture was graphitized at 3,200°C for more than 5 hours to prepare a negative electrode active material.

<Experimental Example 6>

Coal-based needle coke (D10: 7 ㎛, D50: 10 ㎛, D90: 20 ㎛) with a sphericity degree of 0.85 and particle size adjusted was mixed with Coal-based pitch with a softening point of 90°C at room temperature at a ratio of 1:0.13. The room temperature mixing was performed using Kurimoto Sigma-blade type kneader 2Liter scale equipment.

Afterwards, the mixture was kneaded at a temperature of 100°C for 2 hours, cooled naturally, and then discharged at 80°C. Thereafter, the discharged mixture was graphitized at 3,200°C for more than 5 hours to prepare a negative electrode active material.

<Experimental Example 7>

Carboniferous needle coke (D10: 9㎛, D50: 13 ㎛, D90: 25 ㎛) with a sphericity degree of 0.95 and particle size adjusted was mixed with Carboniferous pitch with a softening point of 90°C at room temperature at a ratio of 1:0.13. The room temperature mixing was performed using Kurimoto Sigma-blade type kneader 2Liter scale equipment.

Afterwards, the mixture was kneaded at a temperature of 100°C for 2 hours, cooled naturally, and then discharged at 80°C. Thereafter, the discharged mixture was graphitized at 3,200°C for more than 5 hours to prepare a negative electrode active material.

<Experimental Example 8>

Petroleum-based needle coke (D10: 8 ㎛, D50: 12 ㎛, D90: 24 ㎛) with a sphericity degree of 0.85 and a controlled particle size was mixed with coal-based pitch with a softening point of 90°C at room temperature at a ratio of 1:0.09. The room temperature mixing was performed using Kurimoto Sigma-blade type kneader 2Liter scale equipment.

Afterwards, the mixture was kneaded at a temperature of 100°C for 2 hours, cooled naturally, and then discharged at 80°C. Thereafter, the discharged mixture was graphitized at 3,200°C for more than 5 hours to prepare a negative electrode active material.

<Experimental Example 9>

Petroleum-based needle coke (D10: 8 ㎛, D50: 12 ㎛, D90: 24 ㎛) with a sphericity degree of 0.85 and particle size adjusted was mixed with coal-based pitch with a softening point of 90°C at room temperature at a ratio of 1:0.14. The room temperature mixing was performed using Kurimoto Sigma-blade type kneader 2Liter scale equipment.

Afterwards, the mixture was kneaded at a temperature of 100°C for 2 hours, cooled naturally, and then discharged at 80°C. Thereafter, the discharged mixture was graphitized at 3,200°C for more than 5 hours to prepare a negative electrode active material.

Table 1 below shows the sphericity and particle size distribution of the above-mentioned experimental example and the particle size, sphericity, graphitization degree, specific surface area (BET), tap density, and their relational expressions in the final product.

Pipitch content Primary particle size [㎛] Particle size of active material [㎛] spherical flower painting Surface spacing (d ₀₀₂ ) BBET tap density relational expression [Weight part] D10 D50 D90 Span D10 D50 D90 Span [-] [㎚] [m2/g] [g/cc] Equation 1 Equation 2 Equation 3 Equation 4 Experimental Example 1 0.1 8 12 24 1.33 9 14 29 1.43 0.85 0.3360 1.350 0.760 2.540 3.958 0.3411 1.7763 Comparative Example 1 Experimental Example 2 0.13 8 12 24 1.33 10 16 28 1.13 0.85 0.3360 1.280 0.900 1.607 3.958 0.3234 1.4222 Example 1 Experimental Example 3 0.1 7 10 23 1.6 11 15 30 1.27 0.93 0.3358 1.190 0.950 1.591 4.765 0.2498 1.2526 Example 2 Experimental Example 4 0.13 7 10 23 1.6 9 17 33 1.41 0.93 0.3356 0.330 0.770 0.604 4.768 0.0692 0.4286 Comparative Example 2 Experimental Example 5 0.13 7 10 23 1.6 7 10 23 1.6 0.92 0.3354 1.410 0.850 2.654 4.770 0.2956 1.6588 Comparative Example 3 Experimental Example 6 0.13 7 10 20 1.3 7 10 20 1.3 0.85 0.3355 1.450 0.880 2.142 3.875 0.3742 1.6477 Comparative Example 4 Experimental Example 7 0.13 9 13 25 1.23 9 13 25 1.23 0.95 0.3354 1.240 1.050 1.453 3.667 0.3381 1.1810 Example 3 Experimental Example 8 0.09 8 12 24 1.33 8 13 28 1.54 0.85 0.3359 1.280 0.900 2.190 3.960 0.3233 1.4222 Comparative Example 5 Experimental Example 9 0.14 8 12 24 1.33 12 16 33 1.31 0.85 0.3360 1.480 0.740 2.620 3.958 0.3739 2.0000 Comparative Example 6

1A and 1B are SEM photographs of a negative electrode active material according to an embodiment of the present invention.

1A and 1B are SEM photographs of Experimental Examples 2 and 3 (Examples 1 and 2 of the present invention), respectively. Looking at Experimental Examples 2 and 3 and Table 1, it can be seen that assembly is easy and the electrochemical properties are excellent. You can.

Specifically, it can be confirmed that the physical properties of specific surface area and tap density are influenced by the final particle standard particle size, degree of spheroidization, degree of graphitization, and their relational expressions, and it can be confirmed that electrode processability is inferior due to a decrease in tap density. there is.

Table 2 below shows the characteristics of the anode material manufactured after coke having the particle size of Experiment 3 and Experiment 3 was subjected to different graphitization temperatures as in Experiment 10 and Experiment 11 below, respectively.

<Experimental Example 10>

Petroleum-based needle coke (D10: 8 ㎛, D50: 12 ㎛, D90: 24 ㎛) with a sphericity degree of 0.85 and a controlled particle size was mixed with coal-based pitch with a softening point of 90°C at room temperature at a ratio of 1:0.13. The room temperature mixing was performed using Kurimoto Sigma-blade type kneader 2Liter scale equipment.

Afterwards, the mixture was kneaded at a temperature of 100°C for 2 hours, cooled naturally, and then discharged at 80°C. Thereafter, the discharged mixture was graphitized at 2,600°C for more than 5 hours to prepare a negative electrode active material.

<Experimental Example 11>

Coal-based needle coke (D10: 7 ㎛, D50: 10 ㎛, D90: 23 ㎛) with a sphericity degree of 0.85 and particle size adjusted was mixed with Coal-based pitch with a softening point of 90°C at room temperature at a ratio of 1:0.10. The room temperature mixing was performed using Kurimoto Sigma-blade type kneader 2Liter scale equipment.

Afterwards, the mixture was kneaded at a temperature of 100°C for 2 hours, cooled naturally, and then discharged at 80°C. Thereafter, the discharged mixture was graphitized at 2,600°C for more than 5 hours to prepare a negative electrode active material.

pitch content Primary particle size [㎛] Particle size of active material [㎛] Sphericity Surface spacing
(d ₀₀₂ ) BET tap density Equation 1 Equation 2 Equation 3 Equation 4 note [Weight part] D10 D50 D90 Span D10 D50 D90 Span [-] [㎚] [m2/g] [g/cc] Experimental Example 2 0.13 8 12 24 1.33 10 16 28 1.13 0.85 0.3360 1.280 0.900 1.607 3.958 0.3234 1.4222 Example 1 Experimental Example 3 0.1 7 10 23 1.6 11 15 30 1.27 0.93 0.3358 1.190 0.950 1.591 4.765 0.2498 1.2526 Example 2 Experimental Example 8 0.13 8 12 24 1.33 10 16 28 1.13 0.92 0.3364 1.280 0.900 1.607 3.954 0.3238 1.4222 Comparative Example 7 Experimental Example 9 0.1 7 10 23 1.6 11 15 30 1.27 0.93 0.3362 1.190 0.950 1.591 4.759 0.2500 1.2526 Comparative Example 8

Looking at Table 2 above, it can be seen that when the graphitization temperature is low when manufacturing the negative electrode active material, the degree of graphitization is poor.

<Cathode manufacturing>

A negative electrode active material slurry was prepared by mixing 97% by weight of the negative electrode active material prepared according to the above-described Experimental Examples 1 to 11, 2% by weight of a binder containing carboxymethyl cellulose and styrene butadiene rubber, and 1% by weight of the Super P conductive material in a distilled water solvent. did.

The negative active material slurry was applied to a copper (Cu) current collector, dried at 100° C. for 10 minutes, and pressed in a roll press. Afterwards, a negative electrode was prepared by vacuum drying in a vacuum oven at 100°C for 12 hours.

<Evaluation example: Powder resistance measurement of Examples 1 to 3>

Among the negative electrodes manufactured by the above-described negative electrode manufacturing method, the powder resistance measurement results for the negative electrodes manufactured using the negative electrode active materials of Examples 1 to 3 are shown in Tables 4 to 6 below.

The powder resistance refers to the value based on 10 mg loading on the Cu current collector when manufacturing the electrode, and was measured with a Hantech device.

Load electrical conductivity electrode density [kgf] [S/cm] [g/cc] Experimental Example 2_1 198.5 35.28 1.306 Experimental Example 2_2 199 35.39 1.306 Experimental Example 2_3 199.5 35.5 1.307 Experimental Example 2_4 398.5 65.68 1.471 Experimental Example 2_5 399.5 65.88 1.472 Experimental Example 2_6 400 66.06 1.473 Experimental Example 2_7 598.5 95.06 1.593 Experimental Example 2_8 600 95.42 1.594 Experimental Example 2_9 601 95.58 1.594 Experimental Example 2_10 798.5 123.7 1.691 Experimental Example 2_11 800 123.8 1.692 Experimental Example 2_12 800.5 124.1 1.692 Experimental Example 2_13 997 150.8 1.772 Experimental Example 2_14 1000 151.3 1.774 Experimental Example 2_15 1000 151.6 1.774 Experimental Example 2_16 1197.5 177.9 1.844 Experimental Example 2_17 1200 178.5 1.845 Experimental Example 2_18 1200.5 178.5 1.846

Load electrical conductivity electrode density [kgf] [S/cm] [g/cc] Experimental Example 3_1 198.5 27.18 1.323 Experimental Example 3_2 199.5 27.28 1.324 Experimental Example 3_3 200 27.38 1.325 Experimental Example 3_4 398.5 51.24 1.488 Experimental Example 3_5 399.5 51.42 1.488 Experimental Example 3_6 401 51.57 1.489 Experimental Example 3_7 598.5 74.88 1.608 Experimental Example 3_8 600.5 75.1 1.609 Experimental Example 3_9 600 75.2 1.609 Experimental Example 3_10 799 98.08 1.707 Experimental Example 3_11 800.5 98.28 1.708 Experimental Example 3_12 800 98.48 1.708 Experimental Example 3_13 998 120.4 1.788 Experimental Example 3_14 1001 120.7 1.789 Experimental Example 3_15 1000.5 121 1.789 Experimental Example 3_16 1198 142.5 1.858 Experimental Example 3_17 1200.5 143 1.859 Experimental Example 3_18 1201 14303 1.86

Load electrical conductivity electrode density [kgf] [S/cm] [g/cc] Experimental Example 7_1 198.5 20.89 1.222 Experimental Example 7_2 199 20.96 1.222 Experimental Example 7_3 200 21.03 1.222 Experimental Example 7_4 398.5 38.57 1.368 Experimental Example 7_5 199.5 38.66 1.369 Experimental Example 7_6 400.5 38.77 1.37 Experimental Example 7_7 598.5 55.97 1.482 Experimental Example 7_8 599.5 56.11 1.483 Experimental Example 7_9 600.5 56.19 1.484 Experimental Example 7_10 798.5 73.27 1.578 Experimental Example 7_11 800 73.4 1.579 Experimental Example 7_12 800.5 73.52 1.579 Experimental Example 7_13 997 90.26 1.661 Experimental Example 7_14 999.5 90.46 1.662 Experimental Example 7_15 1000.5 90.76 1.663 Experimental Example 7_16 1197.5 107.2 1.734 Experimental Example 7_17 1200.5 107.7 1.736 Experimental Example 7_18 1200.5 107.9 1.737

Figure 2 is a graph of electrode density according to powder resistance, according to an embodiment of the present invention.

Figure 2 shows powder resistance density according to load in Examples 1 to 3 of the present invention.

Looking at Figure 2 and Tables 3 to 5, it can be seen that the density is 1.45 or more and the electrical conductivity is in the range of 38 to 121 S/cm in the load range of 600 to 1000 kgf.

<Lithium secondary battery manufacturing>

Lithium metal (Li-Metal) was used as the cathode and counter electrode prepared by the above-mentioned method, and the electrolyte was a mixture of ethylene carbonate (EC, Ethylene Carbonate) and dimethyl carbonate (DMC, Dimethyl Carbonate) at a volume ratio of 1:1. 1 mole of LiPF6 solution dissolved in a solvent was used.

Using each of the above components, a 2032 coin cell type half cell was manufactured according to a conventional manufacturing method.

<Evaluation example: Characteristics of lithium secondary battery>

Table 5 below shows the electrochemical properties of the lithium secondary battery manufactured by the above-described method.

Electrode density was measured based on 1C and 10 mg.

Discharge capacity was measured based on 1C, 3rd cycle discharge capacity.

Battery efficiency was measured based on the first cycle discharge/charge capacity.

electrode density Discharge capacity battery efficiency note [g/cc] [mAh/g] [%] Experimental Example 1 1.50 348 93 Comparative Example 1 Experimental Example 2 1.56 355 94 Example 1 Experimental Example 3 1.63 357 93 Example 2 Experimental Example 4 1.47 338 96 Comparative Example 2 Experimental Example 5 1.51 345 92 Comparative Example 3 Experimental Example 6 1.53 348 91 Comparative Example 4 Experimental Example 7 1.65 358 92 Example 3 Experimental Example 8 1.67 354 88 Comparative Example 5 Experimental Example 9 1.53 352 89 Comparative Example 6 Experimental Example 10 1.70 328 94 Comparative Example 7 Experimental Example 11 1.68 331 92 Comparative Example 8

Looking at Table 6 above, when the particle size, interplanar spacing (d ₀₀₂ ), degree of sphericity, and their relational formulas of the negative electrode active material of the present invention are satisfied, the electrode density is 1.55 g/cc or more and the discharge capacity is 350 mAh/g or more. It can be confirmed that the battery efficiency satisfies 92% or more. The present invention is not limited to the above embodiments and can be manufactured in various different forms, and those skilled in the art will understand It will be understood that the present invention may be implemented in other specific forms without changing its technical spirit or essential features. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive.

Claims (15)

Graphite material containing secondary particles,
The secondary particles are assembled from a plurality of primary particles,
The graphite material has a 002 plane spacing (d ₀₀₂ ) of 0.3354 to 0.3362 nm according to X-ray diffraction analysis,
A negative electrode active material that satisfies the following formula 1.
<Equation 1>
1.2 ≤ Span × (specific surface area (BET) [m ² /g]/tap density [g/cc]) ≤ 1.72
(The Span value means (D90-D10)/D50, which is the ratio of the difference between the D90 particle size and D10 particle size to the D50 particle size of the graphite material.)
According to claim 1,
A negative electrode active material that satisfies the following formula 2.
<Equation 2>
3.95 ≤ Sphericity/Span value ≤ 4.80
(The Span value means (D90-D10)/D50, which is the ratio of the difference between the D90 particle size and D10 particle size to the D50 particle size of the graphite material.)
According to claim 1,
A negative electrode active material that satisfies the following formula 3.
<Equation 3>
0.310 ≤ 002 Surface spacing (d ₀₀₂ )/Tap density ≤ 0.400
According to claim 1,
A negative electrode active material that satisfies the following formula 4.
<Equation 4>
1.10 ≤ specific surface area (BET)/tap density ≤ 1.65
According to claim 1,
A negative electrode active material having a sphericity degree of 0.85 to 1.0.
According to claim 1,
A negative electrode active material in which the Span value ((D90-D10)/D50), which is the ratio of the difference between the D90 particle size and the D10 particle size to the D50 particle size of the graphite material, is 1.4 or less.
According to claim 1,
A negative electrode active material with a tap density of 0.8 g/cc or more.
According to claim 1,
A negative electrode active material with a specific surface area (BET) of 1.3 g/m ² or less.
According to claim 1,
A negative electrode active material having an electrical conductivity of 38 to 121 S/cm as measured by powder resistance at a load of 600 to 1000 kgf.
According to claim 1,
A negative electrode active material having a density of 1.45 to 1.80 g/cc as measured by powder resistance at a load of 600 to 1000 kgf.
According to claim 1,
The primary particles are a negative electrode active material in which at least one of coal-based coke and petroleum-based coke is graphitized.
providing primary particles from a carbon source;
Mixing the primary particles and the binder at room temperature for more than 30 minutes;
Injecting the mixed primary particles and the binder into a granulator;
manufacturing secondary particles by assembling the primary particles and the binder introduced into the granulator; and
Comprising the step of graphitizing the assembled secondary particles at 2,700°C or higher,
A method of producing a negative electrode active material wherein the binder content satisfies 10.0 to 13.5 parts by weight based on 100 parts by weight of the primary particles.
According to claim 12,
In the step of providing primary particles from carbon raw materials,
Comprising the step of pulverizing the carbon raw material,
A method of producing a negative electrode active material satisfying at least one of D10: 5 to 10 ㎛, D50: 10 to 18 ㎛, and D90: 20 to 28 ㎛ of the primary particles.
According to claim 12,
The step of manufacturing secondary particles by assembling the primary particles and binder introduced into the granulator is,
A method of manufacturing a negative electrode active material comprising the step of assembling at 30 RPM or more.
According to claim 12,
The step of manufacturing secondary particles by assembling the primary particles and binder introduced into the granulator is,
A method of producing a negative electrode active material comprising the step of assembling the assembled powder through pressurization at 100°C or higher.