Negative active material, method of preparing same, negative electrode including same, and rechargeable lithium battery including same

Abstract

A negative active material, a method of preparing the same, a negative electrode including the same, and a rechargeable lithium battery including the same are provided. The negative electrode active material has a peak intensity ratio (I (110) / I (002)) of a peak intensity at a (110) plane to a peak intensity at a (002) plane of about 30 to about 70 when measured by X-ray diffraction using a CuK [alpha] ray, and includes an aggregate in which spherical graphite and non-spherical artificial graphite are aggregated (e.g., aggregated).

Description

Technical Field

[0001] Embodiments relate to a negative active material, a method of preparing the negative active material, a negative electrode including the negative active material, and a rechargeable lithium battery including the negative electrode. Background Art

[0002] Recently, with the rapid spread of electronic devices using batteries (e.g., mobile phones, laptop computers, and / or electric vehicles), the demand or desire for smaller, lighter, and relatively high-capacity batteries (e.g., rechargeable lithium batteries) is rapidly increasing. Due to their lighter weight and higher energy density compared to other comparable batteries, rechargeable lithium batteries have recently attracted attention as a driving power source for portable devices. Considerations and pursuits have been made to improve the performance of rechargeable lithium batteries.

[0003] Rechargeable lithium batteries include an electrolyte solution and positive and negative electrodes, each containing an active material capable of intercalating and deintercalating lithium ions. When lithium ions are intercalated and deintercalated at the positive and negative electrodes (e.g., when lithium ions are intercalated and deintercalated at the positive and negative electrodes), electrical energy is generated through oxidation and reduction reactions. Summary of the Invention

[0004] Aspects according to one or more embodiments relate to a negative active material exhibiting excellent or suitable electrochemical characteristics.

[0005] Aspects according to one or more embodiments relate to a method of preparing a negative active material.

[0006] Aspects according to one or more embodiments relate to a negative electrode including a negative active material.

[0007] An aspect according to one or more embodiments relates to a rechargeable lithium battery including a negative electrode.

[0008] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the disclosed present embodiments.

[0009] According to one or more embodiments, the negative electrode active material includes an aggregate of spherical artificial graphite and non-spherical artificial graphite, and when measured by X-ray diffraction using CuKα rays, the peak intensity ratio (I (110) / I (002) ) is from about 30 to about 70.

[0010] According to one or more embodiments, the negative electrode includes a negative electrode active material layer, the negative electrode active material layer including a negative electrode active material, the negative electrode active material including an aggregate of spherical artificial graphite and non-spherical artificial graphite, wherein, when measured by X-ray diffraction using CuKα rays, the peak intensity ratio (I (110) / I (002) ) is from about 200 to about 1000.

[0011] According to one or more embodiments, a method of preparing a negative active material includes: mixing a carbon precursor for spherical artificial graphite and non-spherical artificial graphite to form a mixture; aggregating the mixture to form a product; and graphitizing the product.

[0012] According to one or more embodiments, a rechargeable lithium battery includes a negative electrode, a positive electrode, and an electrolyte, the negative electrode including the negative active material.

[0013] According to one or more embodiments, a rechargeable lithium battery includes the negative electrode, a positive electrode, and an electrolyte.

[0014] The negative active material according to one or more embodiments may exhibit excellent or suitable electrochemical characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and other aspects, features and enhancements of certain disclosed embodiments will become more apparent from the following description taken in conjunction with the accompanying drawings, in which: Figure 1 is a schematic diagram of a negative electrode active material according to one or more embodiments; Figure 2 is a schematic diagram of rod-shaped artificial graphite according to one or more embodiments; Figure 3 is a diagram schematically illustrating a cylindrical rechargeable lithium battery according to one or more embodiments of the present disclosure; Figure 4 is a schematic cross-sectional view of a prismatic battery according to one or more embodiments of the present disclosure; Figure 5 is a schematic diagram of a pouch-type battery according to one or more embodiments of the present disclosure; Figure 6 is a schematic diagram of a pouch-type battery according to one or more embodiments of the present disclosure; Figure 7 is a scanning electron microscope (SEM) image of the negative electrode active material prepared in Example 1; Figure 8 is a SEM image of the negative electrode active material prepared by Comparative Example 2; Figure 9 is a SEM image of the negative active material prepared in Comparative Example 1. DETAILED DESCRIPTION

[0016] Hereinafter, embodiments are described in more detail. However, these embodiments are examples, and the present disclosure is not limited thereto, and the scope of the present disclosure is defined by the claims and their equivalents.

[0017] As used herein, unless otherwise defined (e.g., when not otherwise provided), it will be understood that if an element such as a layer, film, region, or substrate is referred to as being "on" another element (e.g., when an element such as a layer, film, region, or substrate is referred to as being "on" another element), it can be directly on the other element or intervening elements may also be present.

[0018] Unless otherwise specified in the specification, expressions in the singular include expressions in the plural. Unless otherwise specified, “A or B” may mean “including A, including B, or including A and B.”

[0019] As used herein, the term "combinations thereof" may include mixtures, laminates, composites, copolymers, alloys, blends, and / or reaction products of the components.

[0020] As used herein, unless otherwise defined (e.g., when no other definition is provided), a particle size may be an average particle size. Such a particle size refers to the average particle size or average particle size (D50) at which the cumulative volume in a particle size distribution accounts for approximately 50% by volume. The average particle size (D50) can be measured by any suitable method, for example, using a particle size analyzer, or by transmission electron microscopy (TEM) or scanning electron microscopy (SEM) images.

[0021] In one or more embodiments, data analysis is performed using a dynamic light scattering measurement device, and the number of particles in each particle size range is counted, from which the average particle size (D50) value can be calculated. The particle size can be measured by laser diffraction.

[0022] Laser diffraction can be obtained by distributing particles to be measured in a distribution solvent and introducing the distribution solvent into a commercially available laser diffraction particle measuring apparatus (e.g., MT 3000 available from Microtrac Corporation), irradiating ultrasonic waves of about 28 kHz at a power of about 60 W, and calculating the average particle size (D50) based on the 50% standard of the particle distribution in the measuring apparatus.

[0023] As used herein, the term "soft carbon" refers to a graphitizable carbon material that is easily graphitized by heat treatment at high temperatures (e.g., about 2800° C.), and the term "hard carbon" refers to a substantially non-graphitizable carbon material that is only slightly graphitizable by heat treatment. The terms soft carbon and hard carbon are known in the relevant art.

[0024] In one or more embodiments, crystalline carbon and amorphous carbon can be distinguished by X-ray diffraction (XRD) measurement. Crystalline carbon includes natural graphite and artificial graphite. Natural graphite may refer to graphite that can be naturally generated and obtained by separating it from a mineral, and if measured by XRD, the interplanar spacing (d002) of the (002) plane may be about 3.350 Å to about 3.360 Å. Artificial graphite may refer to graphite manufactured by graphitization, and if measured by XRD (for example, when measured by XRD), the interplanar spacing (d002) of the (002) plane may be about 3.355 Å to about 3.365 Å. In one or more embodiments, if measured by XRD, the interplanar spacing (d002) of the (002) plane of amorphous carbon may be about 3.34 Å or less. XRD can be measured using CuKα radiation as a target radiation with an X-ray diffraction analyzer (e.g., product name: X'Pert, manufacturer: Malvern Panalytical) by removing the monochromator to improve peak density resolution. Measurement conditions can be 2θ = 10° to 80°, a scan speed (° / s) of 0.044 to 0.089, and a step size (° / step) of 0.013 to 0.039.

[0025] When measured by X-ray diffraction using CuKα rays, the peak intensity ratio (I (110) / I (002) ) is from about 30 to about 70, and includes aggregates of spherical artificial graphite and non-spherical artificial graphite aggregated (eg, agglomerated).

[0026] In one or more embodiments, the peak intensity ratio (I (110) / I (002) ) may be from about 30 to about 60, or from about 30 to about 50. It may be difficult to prepare a peak intensity ratio (I (110) / I (002) ) is less than about 30. If the peak intensity ratio (I (110) / I (002) ) is greater than about 70, the expansion and electrolyte impregnation characteristics may deteriorate.

[0027] The peak intensity can be represented by the height of the peak or the integrated area of ​​the peak. In one or more embodiments, the peak intensity can be represented by the height of the peak.

[0028] In one or more embodiments, XRD is measured by using CuKα radiation as a target radiation and under measurement conditions of 2θ=10° to 80°, a scanning speed (° / S) of 0.044 to 0.089, and a step size (° / step) of 0.013 to 0.039.

[0029] An aggregate in which spherical artificial graphite (e.g., particles) and non-spherical artificial graphite (e.g., particles) are aggregated (e.g., agglomerated) is not a mixture in which only spherical artificial graphite and non-spherical artificial graphite are physically mixed. The term "aggregate" as used herein means, for example, Figure 1 , in which spherical artificial graphite (e.g., particles) 5 are located between non-spherical artificial graphite (e.g., particles) 3 to form agglomerates, and the non-spherical artificial graphite (e.g., particles) 3 are non-oriented negative electrode active materials 1. For example, the orientation of each non-spherical artificial graphite particle 3 is random, and the non-spherical artificial graphite particles 3 are not oriented in any particular direction.

[0030] The electrolyte impregnation of the negative electrode active material can be improved by including the non-spherical artificial graphite in a non-oriented manner (eg, in a state of being random and having no specific orientation).

[0031] If spherical artificial graphite and non-spherical artificial graphite are simply mixed, there may be areas where the non-spherical artificial graphite is aligned (e.g., the non-spherical artificial graphite particles are substantially aligned along a specific orientation). For example, there may be many areas where the non-spherical artificial graphite is aligned in line with the current collector (e.g., the non-spherical artificial graphite particles are aligned parallel or substantially parallel to the current collector). For example, the pressurization behavior (task) during negative electrode preparation may cause the non-spherical artificial graphite particles to be primarily tilted in the longitudinal direction of the current collector, thereby exhibiting degraded electrolyte impregnation. In other words, during the preparation of the negative electrode, the application of pressure may cause the non-spherical artificial graphite particles to align longitudinally along the current collector. Unfortunately, this alignment leads to reduced electrolyte impregnation.

[0032] Because the shapes of spherical artificial graphite and non-spherical artificial graphite can be displayed separately, a simple mixture of spherical artificial graphite and non-spherical artificial graphite can be confirmed by SEM images. However, if they are agglomerated into aggregates, the spherical artificial graphite and non-spherical artificial graphite may appear as agglomerated shapes of spherical artificial graphite and non-spherical artificial graphite in the SEM image, and therefore, the spherical shape and non-spherical shape cannot be clearly distinguished. Therefore, it can be seen that the simple mixture and the aggregate have different structures.

[0033] According to one or more embodiments, the negative electrode active material includes aggregates of spherical artificial graphite and non-spherical artificial graphite, thereby compensating for the shortcomings of spherical artificial graphite and non-spherical artificial graphite and obtaining the advantages of spherical artificial graphite and non-spherical artificial graphite or enhancing the synergistic effect, thereby achieving excellent or suitable electrolyte impregnation ability, rate capability, high capacity and high power characteristics.

[0034] Spherical artificial graphite may be artificial graphite having a substantially spherical shape. The substantially spherical shape may be a perfect sphere with a sphericity of 1, or an elliptical shape. The aspect ratio (length of the major axis / length of the minor axis) of the spherical artificial graphite may be about 1 or greater and less than about 4, or about 1 to 2.

[0035] The non-spherical artificial graphite may be artificial graphite having any shape other than a spherical shape (i.e., different from a spherical shape), and may include, for example, flake artificial graphite, and the flake artificial graphite may be or include plate-shaped graphite, rod-shaped artificial graphite, and / or any suitable combination thereof. In one or more embodiments, the aspect ratio of the non-spherical artificial graphite may be about 4 or greater.

[0036] In one or more embodiments, the maximum major diameter (length) of the rod-shaped artificial graphite may be about 75 μm to about 160 μm. The maximum diameter refers to the length, for example, Figure 2 The size of the long axis (A) among the long axis (A) and the short axis (B) of the rod-shaped (strip-shaped) artificial graphite shown in In one or more embodiments, the long axis may be the maximum long axis.

[0037] The rod-shaped shape refers to a shape that is substantially filled (e.g., has a solid interior) and is elongated in the longitudinal direction, and is different from a shape that is hollow (e.g., has a hollow interior), such as a fiber-shaped shape (e.g., in the form of a fiber) that is not filled. For example, the rod-shaped shape may be cylindrical and / or square.

[0038] If rod-shaped artificial graphite is included as the non-spherical artificial graphite, the compactness (e.g., packing density) of the negative electrode active material layer can be reduced, thereby suppressing or reducing volume expansion that may occur during charge and discharge, and the contact between active materials to serve as lithium ion channels can be enhanced, thereby reducing resistance.

[0039] The length of such rod-shaped artificial graphite can be about 75 μm to about 160 μm, about 80 μm to about 130 μm, or about 80 μm to about 120 μm. If the length of the rod-shaped artificial graphite is less than 75 μm, resistance and expansion may increase, or power characteristics may be degraded. In one or more embodiments, if the length is greater than 160 μm, its size may be too large, for example, greater than the thickness of the negative electrode, thereby causing production problems. In other words, if the length exceeds 160 μm, it may be too large, thereby causing production problems. In one or more embodiments, the length may be a maximum length.

[0040] The aspect ratio of the rod-shaped artificial graphite may be about 4 to about 30, or about 4 to about 20. In one or more embodiments, the aspect ratio may be an average aspect ratio. If the aspect ratio of the rod-shaped artificial graphite is within these ranges, electrical resistance can be reduced, expansion can be suppressed or reduced, and power characteristics can be improved.

[0041] In one or more embodiments, the mixing ratio of the spherical artificial graphite and the non-spherical artificial graphite can be about 10:90 to about 90:10 by weight, about 20:80 to about 80:20 by weight, about 50:50 to about 30:70 by weight, about 70:30 to about 50:50 by weight, or about 40:60 to about 60:40 by weight. If the mixing ratio of the spherical artificial graphite and the non-spherical artificial graphite meets these ranges, the degree of orientation (for example, of the non-spherical artificial graphite) can be reduced, thereby further enhancing the electrolyte impregnation characteristics.

[0042] In one or more embodiments, the size ratio of the non-spherical artificial graphite to the spherical artificial graphite (non-spherical artificial graphite / spherical artificial graphite) can be from about 0.5 to about 1.5, from about 0.5 to about 1.0, or from about 0.8 to about 1.2. The size of the non-spherical artificial graphite can represent (e.g., is) length, and the size of the spherical artificial graphite can represent (e.g., is) particle size. Non-spherical artificial graphite and spherical artificial graphite within these size ratio ranges can easily agglomerate or easily aggregate (e.g., can easily aggregate).

[0043] The aggregate according to one or more embodiments may have an amorphous carbon layer or a metal compound layer formed on its surface. For example, the negative active material according to one or more embodiments may include an aggregate and an amorphous carbon layer or a metal compound on the surface of the aggregate.

[0044] If an amorphous carbon layer or a metal compound layer is present on the surface of the aggregate, electrolyte impregnation can be further enhanced. For example, if the amorphous carbon layer is present on the surface of the aggregate, the strength of the negative electrode active material can be increased and the rebound can be enhanced after pressurization during the preparation of a negative electrode using the negative electrode active material, thereby enhancing electrolyte impregnation. If the metal compound layer is present on the surface of the aggregate, the hydrophilicity of the metal compound can improve electrolyte impregnation.

[0045] In the amorphous carbon layer, the amorphous carbon may be soft carbon, hard carbon, mesophase pitch carbide, sintered coke, and / or (eg, any suitable) combinations thereof.

[0046] In the metal compound layer, the metal compound may be Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and / or any suitable combination thereof. For example, the metal compound may be a metal oxide.

[0047] In one or more embodiments, the thickness of the amorphous carbon layer or the metal compound layer may be about 0.1 μm to about 1 μm, about 0.3 μm to about 0.8 μm, or about 0.3 μm to about 0.5 μm. If the thickness of the amorphous carbon layer or the metal compound layer meets these ranges, suitable or better electrolyte impregnation properties may be exhibited.

[0048] If the negative electrode active material further includes an amorphous carbon layer or a metal compound layer, the amount of the amorphous carbon layer or the metal compound layer may be about 0.01 wt % to about 0.1 wt %, about 0.01 wt % to about 0.05 wt %, or about 0.03 wt % to about 0.05 wt %, based on 100 wt % of the negative electrode active material. If the amount of the amorphous carbon layer or the metal compound layer is within these ranges, the electrolyte impregnation characteristics can be further enhanced.

[0049] The average particle size (D50) of the negative electrode active material according to one or more embodiments (e.g., in the form of particles (e.g., aggregates having an amorphous carbon layer or a metal compound layer on their surfaces)) may be from about 5 μm to about 25 μm, from about 11 μm to about 14 μm, or from about 12 μm to about 14 μm. If the average particle size (D50) of the negative electrode active material is within these ranges, lithium input / output (e.g., intercalation / deintercalation) characteristics may be further enhanced without reducing capacity.

[0050] The negative electrode active material according to one or more embodiments may further include a binder pitch. The binder pitch may be petroleum pitch, coal pitch, intermediate pitch, asphalt carbon, synthetic pitch, synthetic resin and / or (for example, any suitable) combination thereof. Based on 100wt% of the negative electrode active material, the amount of the binder pitch may be greater than about 0wt% and about 20wt% or less, but the present disclosure is not limited thereto. For example, the amount of the binder pitch may be greater than about 0wt% and about 10wt% or less, greater than about 0wt% and about 5wt% or less, or greater than about 0wt% and about 3wt% or less.

[0051] Method for preparing negative electrode active material The negative active material according to one or more embodiments may be prepared by mixing a carbon precursor for spherical artificial graphite and non-spherical artificial graphite to form a mixture; aggregating the resulting mixture to prepare aggregates; and graphitizing the aggregates.

[0052] The mixing ratio of the carbon precursor for spherical artificial graphite and the non-spherical artificial graphite may be adjusted so that the mixing ratio of the spherical artificial graphite and the non-spherical artificial graphite is about 10:90 to about 90:10 by weight, about 20:80 to about 80:20 by weight, or about 50:50 to about 30:70 by weight.

[0053] The carbon precursor for the spherical artificial graphite may be petroleum coke, petroleum pitch, coal pitch, intermediate pitch, pitch carbon, synthetic pitch, and / or (eg, any suitable) combinations thereof.

[0054] Aggregation can be carried out by adding binder pitch and heat treatment (for example, in order to bond spherical artificial graphite and non-spherical artificial graphite together) to the resulting mixture.Binder pitch can be petroleum pitch, coal tar, intermediate pitch, asphalt carbon, synthetic pitch, synthetic resin and / or its (for example, any suitable) combination.The amount of binder pitch can be regulated, as long as it is enough to suitably carry out aggregation (for example, bonding) process, and for example, based on the resulting mixture and binder pitch of 100wt%, the amount of binder pitch can be greater than about 0wt% and about 20wt% or less (for example, greater than 0wt% and about 20wt% at the most) or about 10wt% or less (for example, greater than 0wt% and about 10wt% at the most).Heat treatment can be carried out at about 300 ℃ to about 600 ℃.

[0055] According to mixing and aggregation, the carbon precursor (for example, for spherical artificial graphite) and the non-spherical artificial graphite may be aggregated or agglomerated with each other to prepare a product in which the non-spherical artificial graphite is non-oriented.

[0056] Graphitization may be performed at about 2800°C to about 3100°C, for example, about 2900°C to about 3000°C.

[0057] Graphitization can convert a carbon precursor for spherical artificial graphite into spherical artificial graphite to prepare an aggregate (e.g., agglomerate) of spherical artificial graphite and non-spherical artificial graphite to prepare an aggregate as a negative electrode active material. The carbon precursor, which is in a non-oriented state during mixing and aggregation, can cause the non-spherical artificial graphite to be present in a non-oriented state in the prepared negative electrode active material.

[0058] After graphitization, an amorphous carbon layer or a metal compound layer may be formed on the surface of the aggregate. The formation process may be to coat the aggregate with a coating liquid in which amorphous carbon or a metal compound is dispersed in a solvent.

[0059] The solvent can be water, ethanol, methanol and / or any suitable combination thereof. The concentration of the coating liquid can be about 0.1 wt % to about 10 wt %, about 0.5 wt % to 2 wt %, or about 0.5 wt % to about 0.7 wt %. The coating liquid with a concentration within these ranges can appropriately form an amorphous carbon layer or a metal compound layer on the surface of the aggregate.

[0060] Application can be carried out by spraying or dipping.

[0061] negative electrode The negative electrode according to one or more embodiments includes a negative active material layer, and the negative active material layer includes a negative active material including an aggregate in which spherical artificial graphite and non-spherical artificial graphite are aggregated (eg, agglomerated).

[0062] In the X-ray diffraction measurement of the negative electrode using CuKα radiation, the peak intensity ratio of the peak intensity at the (110) plane to the peak intensity at the (002) plane (I (110) / I (002) ) is from about 200 to about 1000, or may be from about 300 to about 1000, or from about 300 to about 990.

[0063] If the peak intensity ratio of the negative electrode (I (110) / I (002) ) is less than about 200, pressurization may be undesirably performed, and if it is greater than about 1000, expansion of the negative electrode may be (eg, be) severe and the electrolyte may not be desirably impregnated.

[0064] The negative electrode active material is the negative electrode active material according to one or more embodiments. The negative electrode according to one or more embodiments includes a peak intensity ratio (I (110) / I (002) ) is about 30 to about 70, and the peak intensity ratio (I (110) / I(002) ) is from about 200 to about 1000.

[0065] In one or more embodiments, the negative active material layer may further include a binder, and may further include a conductive material (eg, an electron conductor).

[0066] For example, the negative active material layer may include about 90 wt % to about 99 wt % of the negative active material and about 1 wt % to about 10 wt % of the binder, or may include about 90 wt % to about 99 wt % of the negative active material, about 0.5 wt % to about 5 wt % of the binder, and about 0.5 wt % to about 5 wt % of the conductive material.

[0067] The binder can be used to attach the negative electrode active material particles to each other (e.g., well), and also to attach the negative electrode active material to the current collector (e.g., well). The binder can include a non-aqueous binder, an aqueous binder, a dry binder, and / or any suitable combination thereof.

[0068] The non-aqueous binder may include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, and / or (eg, any suitable) combinations thereof.

[0069] The aqueous binder can be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinyl pyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinyl pyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol and / or (e.g., any suitable) combination thereof.

[0070] If an aqueous binder is used as the negative electrode binder, a cellulose compound may be further used as a thickener to increase viscosity. The cellulose compound includes one or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may be Na, K, or Li.

[0071] The dry binder may be a polymer material capable of being fiberized (eg, in the form of fibers), and for example, the dry binder may be polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, and / or (eg, any suitable) combinations thereof.

[0072] Conductive materials can be used to impart conductivity (e.g., electrical or electronic conductivity) to electrodes. Any material that does not cause chemical changes (e.g., does not cause undesirable chemical changes in rechargeable lithium batteries) and conducts electrons can be used in the battery. Non-limiting examples include: carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and / or carbon nanotubes; metal-based materials including copper, nickel, aluminum, and / or silver in the form of metal powders or metal fibers; conductive polymers such as polyphenylene derivatives; and / or (e.g., any suitable) mixtures thereof.

[0073] The negative electrode according to one or more embodiments includes a current collector supporting the negative active material layer. The current collector may include copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and / or any suitable combination thereof.

[0074] Rechargeable lithium battery According to one or more embodiments, a rechargeable lithium battery includes a negative electrode, a positive electrode, and an electrolyte.

[0075] positive electrode The positive electrode may include a current collector and a positive active material layer on the current collector.

[0076] The positive active material layer may include a positive active material, and may further include a binder and / or a conductive material (eg, an electrically conductive or electronically conductive material (eg, an electron conductor)).

[0077] For example, the positive electrode may further include an additive that may function as a sacrificial positive electrode.

[0078] The amount of the positive active material may be about 90 wt % to about 99.5 wt % based on 100 wt % of the positive active material layer, and the amount of the binder and the conductive material may be about 0.5 wt % to about 5 wt %, respectively, based on 100 wt % of the positive active material layer.

[0079] The binder is used to attach the positive electrode active material particles to each other (e.g., well) and also to attach the positive electrode active material to the current collector (e.g., well). Non-limiting examples of the binder may include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers including ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, and / or nylon.

[0080] Conductive materials can be used to impart conductivity (e.g., electrical or electronic conductivity) to electrodes, and any material that does not cause chemical changes (e.g., does not cause undesirable chemical changes in rechargeable lithium batteries) and conducts electrons can be used in batteries. Examples of conductive materials include: carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and / or carbon nanotubes; metal-based materials including copper, nickel, aluminum, and / or silver, in the form of metal powders or metal fibers; conductive polymers such as polyphenylene derivatives; and / or (e.g., any suitable) mixtures thereof.

[0081] Al (aluminum) may be used as the current collector, but the present disclosure is not limited thereto.

[0082] electrolyte The electrolyte for rechargeable lithium batteries includes a non-aqueous organic solvent and a lithium salt.

[0083] The non-aqueous organic solvent may serve as a medium for transporting (eg, transferring or conducting) ions participating in an electrochemical reaction of a battery.

[0084] The non-aqueous organic solvent may be a carbonate solvent, an ester solvent, an ether solvent, a ketone solvent, an alcohol solvent, an aprotic solvent, and / or (eg, any suitable) combination thereof.

[0085] The carbonate solvent may include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), ethylmethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC) and / or butylene carbonate (BC).

[0086] The ester solvent may include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanoic acid lactone, mevalonolactone, valerolactone and / or caprolactone, etc.

[0087] Ether solvents may include dibutyl ether, tetraglyme, diglyme, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, and / or tetrahydrofuran. Ketone solvents may include cyclohexanone, etc. Alcohol solvents may include ethanol, isopropanol, etc., and aprotic solvents may include nitriles such as R-CN (wherein R is a C2 to C20 linear, branched, or cyclic hydrocarbon group and may include a double bond, an aromatic ring, and / or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane and 1,4-dioxolane; and / or sulfolane.

[0088] The non-aqueous organic solvents may be used alone or in combination of two or more.

[0089] If a carbonate-based solvent is used, a cyclic carbonate and a chain carbonate may be used in combination, and the cyclic carbonate and the chain carbonate may be mixed in a volume ratio of about 1:1 to about 1:9.

[0090] Lithium salts dissolved in organic solvents supply lithium ions in the battery, enable basic operation of the rechargeable lithium battery, and improve the transport of lithium ions between the positive electrode and the negative electrode. Examples of lithium salts include those selected from LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N (lithium bis(fluorosulfonyl)imide, LiFSI), LiC4F9SO3, LiN(C F 2x+1 SO2)(C y F 2y+2 SO2) (wherein, x and y are each independently an integer from 1 to 20), at least one of lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluorobis(oxalato)phosphate (LiDFBOP) and lithium bis(oxalato)borate (LiBOB).

[0091] diaphragm Depending on the type or kind of rechargeable lithium battery, a separator may be present between the positive electrode and the negative electrode. The separator may include polyethylene, polypropylene, polyvinylidene fluoride, a multilayer film of two or more layers thereof, and / or a mixed multilayer film, such as a polyethylene / polypropylene double-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, a polypropylene / polyethylene / polypropylene three-layer separator, etc.

[0092] The separator may include a porous substrate and a coating including an organic material, an inorganic material, and / or (eg, any suitable) combination thereof on a surface (eg, one or both surfaces (eg, opposing surfaces)) of the porous substrate.

[0093] The porous substrate may be a polymer film formed from any one selected from polyolefins (such as polyethylene and / or polypropylene), polyesters (such as polyethylene terephthalate and / or polybutylene terephthalate), polyacetals, polyamides, polyimides, polycarbonates, polyetherketones, polyaryletherketones, polyetherimides, polyamideimides, polybenzimidazoles, polyethersulfones, polyphenylene oxides, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fibers, and polytetrafluoroethylene (e.g., Teflon), or copolymers or mixtures of two or more thereof.

[0094] The organic material may include a polyvinylidene fluoride-based polymer or a (meth)acrylic polymer.

[0095] The inorganic material may include inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite and / or (e.g., any suitable) combinations thereof, but the present disclosure is not limited thereto.

[0096] An organic material and an inorganic material may be mixed in one coating layer, or a coating layer including an organic material and a coating layer including an inorganic material may be stacked.

[0097] Rechargeable lithium batteries may be classified according to their shape into cylindrical batteries, prismatic batteries, pouch batteries, and / or coin-type (or similar) batteries, etc. Figures 3 to 6 is a schematic diagram illustrating a rechargeable lithium battery according to one or more embodiments. Figure 3 shows a cylindrical battery, Figure 4 shows a prismatic cell, Figure 5 and Figure 6 Pouch type (or similar) battery is shown. Figures 3 to 6 , the rechargeable lithium battery 100 may include an electrode assembly 40 including a separator 30 between a positive electrode 10 and a negative electrode 20 and a case 50 including the electrode assembly. The positive electrode 10, the negative electrode 20, and the separator 30 may be impregnated with an electrolyte. Figure 3 As shown in , the rechargeable lithium battery 100 may include a sealing member 60 that seals the case 50. Figure 4 In the embodiment, the rechargeable lithium battery 100 may include a positive electrode lead tab 11, a positive electrode terminal 12, a negative electrode lead tab 21, and a negative electrode terminal 22. Figure 5 and Figure 6 As shown in , the rechargeable lithium battery 100 may include electrode tabs 70 , which may be, for example, a positive electrode tab 71 and a negative electrode tab 72 serving as electrical paths for inducing current formed in the electrode assembly 40 to the outside.

[0098] Hereinafter, examples and comparative examples of the present disclosure are described. However, these examples are not to be construed as limiting the scope of the present disclosure in any sense.

[0099] (Example 1) Petroleum coke having an aspect ratio of 1.2 and rod-shaped artificial graphite having a maximum length of 80 μm and an average aspect ratio of 5 to 10 are mixed in a weight ratio of 50:50, and the mixture is subjected to an aggregation process in which 97 wt% of the mixture and 3 wt% of coal tar pitch as a binder pitch are added (e.g., mixed), and then heat-treated at 500°C to prepare aggregates.

[0100] The aggregate was heat-treated at 3000°C to convert petroleum coke into artificial graphite having an aspect ratio of 1.2, and a negative electrode active material in which spherical artificial graphite and non-spherical artificial graphite were aggregated (e.g., agglomerated) was prepared to prepare an aggregate (amount of binder pitch: 2 wt%), i.e., a negative electrode active material.

[0101] 96 wt % of the negative electrode active material, 3 wt % of styrene butadiene rubber, and 1 wt % of carboxymethyl cellulose were mixed in a water solvent to prepare a negative electrode active material slurry.

[0102] The negative active material slurry was coated on a Cu foil current collector through a general procedure, dried and pressed to prepare a negative electrode including the current collector and the negative active material layer on the current collector.

[0103] A rechargeable lithium battery was fabricated using a negative electrode, a lithium metal counter electrode, and an electrolyte containing 1.5 M LiPF6 dissolved in a mixed solvent of ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate (20:10:70 by volume).

[0104] (Example 2) A negative active material was prepared by the same procedure as in Example 1, except that petroleum coke and rod-shaped artificial graphite were mixed at a weight ratio of 70:30.

[0105] Using this negative electrode active material, a negative electrode and a coin-type (or like) half-cell were manufactured through the same steps as in Example 1.

[0106] (Example 3) A negative active material was prepared by the same procedure as in Example 1, except that petroleum coke and rod-shaped artificial graphite were mixed at a weight ratio of 30:70.

[0107] Using this negative electrode active material, a negative electrode and a coin-type (or like) half-cell were manufactured through the same steps as in Example 1.

[0108] (Example 4) Al2O3 was added to ethanol as a solvent to prepare a metal oxide liquid (dispersion liquid) having a solid content of 0.5 wt%.

[0109] The aggregates of spherical artificial graphite and rod-shaped artificial graphite prepared in Example 1 were coated with a metal oxide solution and dried to prepare a negative electrode active material having an Al2O3 coating layer with a thickness of 0.5 μm formed on the surface of the aggregates. The amount of the metal oxide was 0.05 wt% based on 100 wt% of the negative electrode active material.

[0110] Using this negative electrode active material, a negative electrode and a coin-type (or like) half-cell were manufactured through the same steps as in Example 1.

[0111] (Example 5) A negative electrode active material was prepared by the same procedure as in Example 4, except that petroleum coke and rod-shaped artificial graphite were mixed at a weight ratio of 70:30.

[0112] Using this negative electrode active material, a negative electrode and a coin-type (or like) half-cell were manufactured through the same steps as in Example 1.

[0113] (Example 6) A negative active material was prepared by the same procedure as in Example 4, except that petroleum coke and rod-shaped artificial graphite were mixed at a weight ratio of 30:70.

[0114] Using this negative electrode active material, a negative electrode and a coin-type (or like) half-cell were manufactured through the same steps as in Example 1.

[0115] (Comparative Example 1) Petroleum coke was heat-treated at 3000°C to prepare spherical artificial graphite used as the negative electrode active material.

[0116] Using this negative electrode active material, a negative electrode and a coin-type (or like) half-cell were manufactured through the same steps as in Example 1.

[0117] (Comparative Example 2) Rod-shaped artificial graphite having a maximum length of 80 μm and an average aspect ratio of 5 to 10 was used as the negative electrode active material.

[0118] Using this negative electrode active material, a negative electrode and a coin-type (or like) half-cell were manufactured through the same steps as in Example 1.

[0119] (Comparative Example 3) Petroleum coke was heat-treated at 3000°C to prepare spherical artificial graphite used as the negative electrode active material.

[0120] Spherical artificial graphite and rod-shaped artificial graphite having a maximum length of 80 μm and an average aspect ratio of 5 to 10 were mixed at a weight ratio of 50:50 to prepare a negative active material.

[0121] Using this negative electrode active material, a negative electrode and a coin-type (or like) half-cell were manufactured through the same steps as in Example 1.

[0122] (Comparative Example 4) Petroleum coke was heat-treated at 3000°C to prepare spherical artificial graphite used as the negative electrode active material.

[0123] Spherical artificial graphite and rod-shaped artificial graphite having a maximum length of 80 μm and an average aspect ratio of 5 to 10 were mixed at a weight ratio of 70:30 to prepare a negative active material.

[0124] Using this negative electrode active material, a negative electrode and a coin-type (or like) half-cell were manufactured through the same steps as in Example 1.

[0125] (Comparative Example 5) Petroleum coke was heat-treated at 3000°C to prepare spherical artificial graphite used as the negative electrode active material.

[0126] The spherical artificial graphite was mixed with rod-shaped artificial graphite having a maximum length of 80 μm and an average aspect ratio of 5 to 10 at a weight ratio of 30:70 to prepare a negative active material.

[0127] A negative electrode and a half-cell were manufactured by the same steps as in Example 1 using this negative electrode active material.

[0128] (Comparative Example 6) Petroleum coke was heat-treated at 3000°C to prepare spherical artificial graphite used as the negative electrode active material.

[0129] Spherical artificial graphite and rod-shaped artificial graphite having a maximum length of 80 μm and an average aspect ratio of 5 to 10 were mixed at a weight ratio of 80:20 to prepare a negative active material.

[0130] Using this negative electrode active material, a negative electrode and a coin-type (or like) half-cell were manufactured through the same steps as in Example 1.

[0131] Experimental Example 1) SEM image The SEM image of the negative electrode active material prepared in Example 1 is Figure 7 From Figure 7 It can be seen that the negative active material prepared according to Example 1 has aggregates in which spherical artificial graphite and rod-shaped artificial graphite are aggregated (eg, agglomerated).

[0132] Figure 7 SEM images of Figure 8 The SEM images of Comparative Example 2 using only rod-shaped artificial graphite and Figure 9 The SEM image of Comparative Example 1 using only spherical artificial graphite shown in FIG.

[0133] Experimental Example 2) Physical Properties of Negative Electrode Active Materials The average particle diameters (D50) of the negative active materials according to Examples 1 to 6 and Comparative Examples 1 to 6 were measured using a particle size analyzer. The results are shown in Table 1.

[0134] 1 g of the negative electrode active material from Examples 1 to 6 and Comparative Examples 1 to 6 was placed in a mold and held under a pressure of 2 tons (pressing force) for 30 seconds to prepare pellets. The density was determined from the pellet thickness and area. The results are shown in Table 1.

[0135] Experimental Example 3) Evaluation of electrolyte immersion 96 wt% of the negative electrode active material according to Examples 1 to 6 and Comparative Examples 1 to 6, 3 wt% of styrene butadiene rubber, and 1 wt% of carboxymethyl cellulose were mixed in water as a solvent to prepare a negative electrode active material slurry. The negative electrode active material slurry was dried for 24 hours to prepare a negative electrode active material slurry powder. 1 g of the prepared negative electrode active material slurry powder was placed in a mold and pressure was applied thereto to prepare 1.5 g / cc pellets. An electrolyte was dripped onto the pellets to measure the time until the electrolyte was completely impregnated.

[0136] The electrolyte was prepared by dissolving 1.5 M LiPF6 in ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate (30:50:20 volume ratio).

[0137] The results are shown in Table 1 by immersion time.

[0138] Experimental Example 4) Measurement of Peak Intensity Ratio Regarding the negative active materials and the negative electrodes according to Examples 1 to 6 and Comparative Examples 1 to 6, X-ray diffraction peak intensity was measured by using CuKα rays.

[0139] The measurement conditions were set as 2θ = 10° to 80°, a scanning speed (° / s) of 0.044, and a step size (° / step) of 0.013° / step.

[0140] The results are shown in Table 1.

[0141] Experimental Example 5) Capacity Evaluation The half cells according to Examples 1 to 6 and Comparative Examples 1 to 6 were charged and discharged once at 0.1 C and once at 0.2 C to measure the charge capacity at 0.2 C. The results are shown in Table 2.

[0142] Experimental Example 6) Evaluation of charging and discharging efficiency The half-cells according to Examples 1 to 6 and Comparative Examples 1 to 6 were charged and discharged once at 0.1 C to measure the charge and discharge capacities. The ratio of the discharge capacity to the charge capacity was calculated. The results are shown in Table 2 as efficiency.

[0143] Experimental Example 7) Evaluation of Chargeability The half-cells according to Examples 1 to 6 and Comparative Examples 1 to 6 were charged and discharged once at 0.2 C and once at 2.0 C. The ratio of the constant-current charge capacity at 2.0 C to the constant-current charge capacity at 0.2 C was calculated. The results are shown in Table 2 as chargeability.

[0144] Table 1

[0145] Table 2

[0146] As shown in Table 1, the X-ray diffraction results of the negative active materials according to Examples 1 to 6 each showed a peak intensity ratio (I (110) / I (002) ) is 30 to 70, and the peak intensity ratio of each negative electrode (I (110) / I (002) ) is in the range of 200 to 1000. The electrolyte solution impregnation time of each of Examples 1 to 6 is 4 to 7 seconds, showing better electrolyte solution impregnation ability than the comparative example.

[0147] The batteries including the negative active materials of Examples 1 to 6 each exhibited similar efficiencies to those of Comparative Examples 1 to 6, but exhibited slightly higher capacities and better charge rates than those of Comparative Examples 1 to 6.

[0148] The use of "may" when describing embodiments of the inventive concept means "one or more embodiments of the inventive concept."

[0149] As used herein, the term "about" and similar terms are used as terms of approximation, not as terms of degree, and are intended to account for the inherent variation in measured or calculated values ​​that one of ordinary skill in the art would recognize. As used herein, "about" is inclusive of the stated value and means an acceptable range of variation for the particular value as determined by one of ordinary skill in the art to take into account uncertainties and errors associated with the measurement of a particular quantity (i.e., limitations of the measurement system). For example, "about" can mean within one or more standard deviations, or within ±30%, ±20%, ±10%, ±5% of the stated value.

[0150] In addition, any numerical range listed herein is intended to include all subranges of the same numerical precision contained within the listed range. For example, the range of "1.0 to 10.0" is intended to include all subranges between (and including) the listed minimum value of 1.0 and the listed maximum value of 10.0, i.e., having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Any maximum numerical limit listed herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit listed in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to amend this specification (including the claims) to explicitly recite any subranges contained within the ranges explicitly recited herein.

[0151] Here, unless otherwise defined, listing steps, tasks, or actions in a particular order does not necessarily mean that the invention or the claims require that particular order. That is, as a general rule, unless the steps, tasks, or actions of a method (e.g., a method claim) actually list an order, the steps, tasks, or actions should not be construed as requiring an order.

[0152] Expressions such as “at least one of” and “any of” when following a list of elements modify the entire list and do not modify the individual elements in the list. When phrases such as “at least one of A, B, and C,” “at least one of A, B, or C,” “at least one selected from the group of A, B, and C,” or “at least one selected from among A, B, and C” are used to refer to a list of elements A, B, and C, the phrase may refer to any suitable combination (or subset) of A, B, and C and all suitable combinations (or subsets), such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the term “use” and variations thereof may be considered synonymous with the term “utilize” and variations thereof, respectively.

[0153] Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments.

[0154] In this disclosure, when particles are spherical, "diameter" refers to the particle diameter or average particle size, and when particles are non-spherical, "diameter" refers to the major axis length or average major axis length. Battery formation or manufacturing systems, battery management system (BMS) devices, and / or any other related devices or components according to embodiments of the present invention described herein can be implemented using any suitable hardware, firmware (e.g., an application-specific integrated circuit), software, or a combination of software, firmware, and hardware. For example, the various components of the device can be formed on a single integrated circuit (IC) chip or on separate IC chips. Furthermore, the various components of the device can be implemented on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board (PCB), or on a single substrate. Furthermore, the various components of the device can be processes or threads running on one or more processors in one or more computing devices, executing computer program instructions and interacting with other system components to perform the various functions described herein. The computer program instructions are stored in memory, which can be implemented in the computing device using standard memory devices such as random access memory (RAM). The computer program instructions can also be stored on other non-transitory computer-readable media such as CD-ROMs, flash drives, and the like. Furthermore, those skilled in the art will recognize that the functionality of various computing devices may be combined or integrated into a single computing device, or that the functionality of a particular computing device may be distributed across one or more other computing devices without departing from the scope of the present disclosure.

[0155] While the present disclosure has been described in conjunction with what are presently considered to be practical example embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments, but, on the contrary, is intended to cover one or more suitable modifications and equivalent arrangements included within the spirit and scope of the appended claims and their equivalents.

Claims

1. A negative electrode active material, comprising: Aggregates of spherical artificial graphite and non-spherical artificial graphite, The peak intensity ratio of the peak intensity of the negative electrode active material at the (110) plane to the peak intensity at the (002) plane, when measured by X-ray diffraction using CuKα rays, is 1 (110) / I (002) 30 to 70.

2. The negative electrode active material according to claim 1, wherein The non-spherical artificial graphite includes flake artificial graphite.

3. The negative electrode active material according to claim 2, wherein The flake-shaped artificial graphite includes plate-shaped graphite, rod-shaped artificial graphite or a combination thereof.

4. The negative electrode active material according to claim 3, wherein The maximum length of the rod-shaped artificial graphite is 75 μm to 160 μm.

5. The negative electrode active material according to claim 3, wherein The rod-shaped artificial graphite has an aspect ratio of 4 to 30.

6. The negative electrode active material according to claim 1, wherein The mixing ratio of the spherical artificial graphite and the non-spherical artificial graphite is 10:90 to 90:10 by weight.

7. The negative electrode active material according to claim 1, further comprising: an amorphous carbon layer or a metal compound layer on the surface of the aggregate.

8. The negative electrode active material according to claim 7, wherein the amorphous carbon layer is on the surface of the aggregate, and wherein The amorphous carbon layer includes soft carbon, hard carbon, mesophase pitch carbide, sintered coke, or a combination thereof.

9. The negative electrode active material according to claim 7, wherein The metal compound layer is on the surface of the aggregate, and wherein the metal compound layer includes Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite or a combination thereof.

10. The negative electrode active material according to claim 7, wherein The amorphous carbon layer or the metal compound layer has a thickness of 0.1 μm to 1 μm.

11. The negative electrode active material according to claim 1, wherein The negative electrode active material is in the form of particles, and the particles have an average particle size D50 of 5 μm to 25 μm.

12. A negative electrode, comprising: A negative electrode active material layer, the negative electrode active material layer comprising an aggregate of spherical artificial graphite and non-spherical artificial graphite, The peak intensity ratio of the peak intensity of the negative electrode at the (110) plane to the peak intensity at the (002) plane, when measured by X-ray diffraction using CuKα rays, is 1 (110) / I (002) 200 to 1000.

13. The negative electrode according to claim 12, wherein The mixing ratio of the spherical artificial graphite and the non-spherical artificial graphite is 10:90 to 90:10 by weight.

14. The negative electrode according to claim 12, further comprising: an amorphous carbon layer or a metal compound layer on the surface of the aggregate.

15. The negative electrode according to claim 12, wherein The non-spherical artificial graphite includes flake artificial graphite.

16. A method comprising: A carbon precursor for spherical artificial graphite and non-spherical artificial graphite are mixed to form a mixture, agglomerating the mixture to form aggregates; as well as graphitizing the aggregates, Wherein, the method is a method for preparing negative electrode active material.

17. The method according to claim 16, wherein The carbon precursor for spherical artificial graphite includes petroleum coke, coal coke, petroleum pitch, coal pitch, intermediate pitch, pitch carbon, synthetic pitch, synthetic resin or a combination thereof.

18. The method according to claim 16, wherein The graphitization is performed by heat treatment at 2800°C to 3100°C.

19. A rechargeable lithium battery, comprising: A negative electrode comprising the negative active material according to claim 1; positive electrode; as well as electrolyte.

20. A rechargeable lithium battery, comprising: The negative electrode according to any one of claims 12 to 15; a positive electrode; and electrolyte.

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