Silicon-carbon composite, negative electrode active material, negative electrode composition, negative electrode and secondary lithium battery

Description

1 / 34 “SILICON-CARBON COMPOSITE, NEGATIVE ELECTRODE ACTIVE MATERIAL, NEGATIVE ELECTRODE COMPOSITION, NEGATIVE ELECTRODE AND LITHIUM SECONDARY BATTERY” TECHNICAL FIELD

[001] This application claims priority and benefit of Korean Patent Application No. 10-2023-0136853, filed on October 13, 2023, the description of which is incorporated herein by reference in its entirety.

[002] The present application relates to a silicon-carbon composite, a negative electrode active material, a negative electrode composition, a negative electrode and a lithium secondary battery. BACKGROUND

[003] Recently, with the rapid spread of electronic devices that use batteries, such as cell phones, laptops, electric vehicles, power tools, and electric cleaners, the demand for small, lightweight secondary batteries with relatively high capacity and / or high efficiency is rapidly increasing. In particular, lithium secondary batteries stand out as a power source for electronic devices due to their light weight and high energy density. Consequently, research and development efforts to improve the performance of lithium secondary batteries are being actively conducted.

[004] In general, a secondary lithium battery includes a positive electrode, a negative electrode, a separator interposed between the positive and negative electrodes, an electrolyte, an organic solvent, and the like. Furthermore, the positive and negative electrodes may be formed into current collectors with layers of active material, each including a positive electrode active material and a negative electrode active material. Generally, for the positive electrode, a lithium-containing metal oxide, such as LiCoO2 and LiMn2O4, is used as the positive electrode active material, and for the negative electrode, a carbon-based active material or Petition 870250085647, dated 09 / 22 / 2025, page 11 / 54 2 / 34 A silicon-based active material that does not contain lithium is used as the active material for the negative electrode.

[005] Batteries that use graphite as the active material of the negative electrode can have a high discharge voltage of 3.6 V, but there is a limit to the increase in energy density due to the low capacity.

[006] On the other hand, silicon-based active materials exhibit high capacity and efficiency and, consequently, are attracting attention as next-generation negative electrode active materials. Therefore, there is a demand for the development of silicon-based active materials with high capacity or efficiency characteristics. SUMMARY OF THE INVENTION Technical Problem

[007] An exemplary embodiment of the present disclosure has been developed with the aim of providing a silicon-carbon composite that can be used as a negative electrode active material with excellent capacity and / or efficiency characteristics.

[008] An exemplary embodiment of the present disclosure has been developed with the aim of providing a silicon-carbon composite that can be used as a negative electrode active material with excellent water-based processability and reduced gas generation.

[009] An exemplary embodiment of the present disclosure has been developed with the aim of providing a silicon-carbon composite that can be used as a negative electrode active material with excellent service life characteristics.

[010] An exemplary embodiment of the present disclosure has been developed with the aim of providing an active negative electrode material, a negative electrode composition, a negative electrode and a lithium secondary battery including the silicon-carbon composite. Petition 870250085647, dated 09 / 22 / 2025, page 12 / 54 3 / 34 Technical Solution

[011] An exemplary embodiment of the present disclosure provides a silicon-carbon composite that satisfies the condition 3 < ((B + C) / A) < 4, wherein A is an intensity of peak A with a chemical shift value in the range of 20 ppm to 15 ppm in a 29Si-MAS NMR spectrum, B is an intensity of peak B with a chemical shift value in the range of -20 ppm to -100 ppm in the 29Si-MAS NMR spectrum; and C is an intensity of peak C with a chemical shift value in the range of -110 ppm to -140 ppm in the 29Si-MAS NMR spectrum.

[012] In an exemplary embodiment of the present disclosure, the silicon-carbon composite may comprise carbon in an amount of 38 parts by weight to 50 parts by weight, based on 100 parts by weight of the silicon-carbon composite.

[013] In an exemplary embodiment of the present disclosure, the silicon-carbon composite may be a particle comprising a porous carbon-silicon-based particle disposed in at least a portion of an interior and a surface of the porous carbon-based particle, or a particle comprising a porous silicon-carbon-based particle disposed in at least a portion of an interior and a surface of the porous silicon-based particle.

[014] In an exemplary embodiment of the present disclosure, the silicon-carbon composite may further comprise a carbon layer formed on a surface of the silicon-carbon composite, and the total weight of the carbon layer may be from 5% by weight to 40% by weight, based on 100% by weight of the silicon-carbon composite.

[015] In an exemplary embodiment of the present disclosure, the silicon-carbon composite may have a pore volume of 0.005 to 0.03 cm3 / g.

[016] In an exemplary embodiment of the present disclosure, the silicon-carbon composite may have a pore size of 10 nm to 20 nm. Petition 870250085647, dated 09 / 22 / 2025, page 13 / 54 4 / 34

[017] In an exemplary embodiment of the present disclosure, the silicon-carbon composite may have a particle diameter D90 of 5 to 15 μm, a particle diameter D50 of 1 to 10 pm, Dmin (D minimum) of 1 to 3 μm and Dmax (D maximum) of 17 to 23 pm.

[018] An exemplary embodiment of the present disclosure provides an active negative electrode material, including the silicon-carbon composite, according to the exemplary embodiment described above.

[019] In an exemplary embodiment of the present disclosure, the negative electrode active material may comprise silicon-carbon composite in an amount of 0.1 parts by weight to 14 parts by weight, based on 100 parts by weight of the negative electrode active material.

[020] In an exemplary embodiment of the present disclosure, the active material of the negative electrode may further include a carbon-based active material, and the carbon-based active material may be included in an amount of 86 parts by weight or more and 99.9 parts by weight or less based on 100 parts by weight of the active material of the negative electrode.

[021] An exemplary embodiment of the present disclosure provides a negative electrode composition including the active material of the negative electrode, according to the exemplary embodiment described above; a binder; and a conductive material.

[022] In an exemplary embodiment of the present disclosure, the active material of the negative electrode included in the composition of the negative electrode may further comprise a carbon-based active material.

[023] An exemplary embodiment of the present disclosure provides a negative electrode including the negative electrode composition, according to the exemplary embodiment described above.

[024] An exemplary embodiment of the present disclosure provides a secondary lithium battery including the negative electrode, according to the embodiment Petition 870250085647, dated 09 / 22 / 2025, p. 14 / 54 5 / 34 example described above, a positive electrode and a separator.

[025] An exemplary embodiment of the present disclosure provides a battery module including the secondary lithium battery, according to the exemplary embodiment described above.

[026] An exemplary embodiment of the present disclosure provides a battery pack including the secondary lithium battery, according to the exemplary embodiment described above.

[027] An exemplary embodiment of the present disclosure provides a battery pack including the battery module, according to the exemplary embodiment described above.

[028] An exemplary embodiment of the present disclosure provides a method for preparing a silicon-carbon composite, the method comprising: carrying out a disproportionality reaction.by heat treatment of a silicon oxide powder; corroding the heat-treated silicon oxide powder with an etching agent; and obtaining a silicon-based porous particle by pulverizing the corroded silicon oxide powder; and forming a silicon-carbon composite by reacting the silicon-based porous particle with a carbon source to form a carbon layer on the surface of the silicon-based porous particle, wherein the silicon-carbon composite satisfies a condition of 3 < ((B + C) / A) < 4, wherein A is an intensity of peak A with a chemical shift value in the range of 20 ppm to -15 ppm in a 29Si-MAS NMR spectrum, B is an intensity of peak B with a chemical shift value in the range of -20 ppm to -100 ppm in the 29Si-MAS NMR spectrum; and C is a C peak intensity with a chemical shift value in the range of -110 ppm to -140 ppm in the 29Si-MAS NMR spectrum.

[029] An exemplary embodiment of the present disclosure provides another method for preparing a silicon-carbon composite, the method comprising: depositing silicon onto a porous carbon particle by chemical vapor deposition, in Petition 870250085647, dated 09 / 22 / 2025, page 15 / 54 6 / 34 that the method optionally further comprises the formation of a carbon layer on a silicon surface deposited on the porous carbon particle, wherein the silicon-carbon composite satisfies a condition of 3 < ((B + C) / A) < 4, wherein A is the intensity of a peak with a chemical shift value in the range of 20 ppm to -15 ppm in a 29Si-MAS NMR spectrum, B is the intensity of a peak with a chemical shift value in the range of -20 ppm to -100 ppm in the 29Si-MAS NMR spectrum; and C is the intensity of a peak with a chemical shift value in the range of -110 ppm to -140 ppm in the 29Si-MAS NMR spectrum. Technical Effect

[030] According to the exemplary embodiments of the present disclosure, it is possible to provide a secondary lithium battery with enhanced capacity and / or efficiency, satisfying the condition that the intensities of a plurality of chemical shift values ​​within a specific range in the NMR spectrum of 29Si-MAS are within a specific ratio range. Specifically, the lifespan characteristics and / or water-based processability can be enhanced by satisfying the condition that the intensity ratio between peaks within a specific range is within a specific range.Within the intensity ratio range according to the exemplary embodiments of the present disclosure, the higher the intensity, the greater the advantages in capacity and efficiency, the alteration in phase stability (viscosity) in the negative electrode paste, including a binder such as carboxymethylcellulose (CMC), is reduced and the generation of gases such as H2 is reduced, resulting in improved water-based processability. BRIEF DESCRIPTION OF THE DRAWINGS

[031] Figure 1 is a graph showing the results of the NMR analysis of the silicon-carbon composites prepared in Example 1. Petition 870250085647, dated 09 / 22 / 2025, page 16 / 54 7 / 34

[032] Figure 2 is a graph showing the results of the NMR analysis of the silicon-carbon composites prepared in Example 2.

[033] Figure 3 is a graph showing the results of the NMR analysis of the silicon-carbon composites prepared in Example 3.

[034] Figure 4 is a graph showing the results of the NMR analysis of the silicon-carbon composites prepared in Comparative Examples 1, 2 and 5.

[035] Figure 5 is a graph showing the results of the NMR analysis of the silicon-carbon composites prepared in Comparative Example 3.

[036] Figure 6 is a graph showing the results of the NMR analysis of the silicon-carbon composites prepared in Comparative Example 6.

[037] Figure 7 is a graph showing the results of the NMR analysis of the silicon-carbon composites prepared in Comparative Example 7.

[038] Figure 8 shows a waveform analysis result based on the NMR analysis result of the silicon-carbon composite from Example 2. DETAILED DESCRIPTION

[039] The present disclosure will now be described in more detail for a better understanding of the present disclosure. The present disclosure can be implemented in a variety of different forms and is not limited to the exemplary embodiments described in this document. The terms or words used throughout the descriptive report and claims should not be interpreted as limited to their common or dictionary meanings, but rather as having meanings and concepts consistent with the technical idea of ​​the present disclosure, based on the principle that an inventor can adequately define the concepts of words or terms to better explain the invention.

[040] It should be understood that terms such as includes, comprises or has are intended to indicate the presence of a feature, number, stage, component or a combination thereof disclosed in this descriptive report and do not exclude Petition 870250085647, dated 09 / 22 / 2025, p. 17 / 54 8 / 34 the possibility of the presence or addition of one or more other characteristics or numbers, stages, components or combinations thereof.

[041] Furthermore, it should be understood that when an element, such as a layer, is referred to as being on top of another element, it may be directly on top of the other element or an intervening element may also be present. In contrast, when an element is referred to as being directly on top of another element, there are no intervening elements present. Furthermore, when an element is referred to as being above or on top of a reference portion, the element is positioned above or below the reference portion, and this does not necessarily mean that the element is positioned above or on top of it in a direction opposite to gravity.

[042] It should be understood that the terms or words used throughout the descriptive report should not be interpreted as limited to their common or dictionary meanings, but rather as having meanings and concepts consistent with the technical idea of ​​the present disclosure, based on the principle that an inventor can adequately define the concepts of words or terms to better explain the invention.

[043] As used in this document, the singular forms a, an and the must also include plural forms, unless the context clearly indicates otherwise.

[044] Next, the preferred embodiments of the present disclosure will be described in detail. However, it should be understood that exemplary embodiments of the present disclosure may be modified in various ways and the scope of the present disclosure is not limited to the exemplary embodiments described below.

[045] A silicon-carbon composite, according to an exemplary embodiment of the present disclosure, has the characteristic that the ratio between the sum of the intensities of peak B and peak C and the intensity of peak A, ((B + C) / A), is 3 or Petition 870250085647, dated 09 / 22 / 2025, p. 18 / 54 9 / 34 greater and less than 4, where A is the intensity of peak A with a chemical shift value in the range of 20 ppm to -15 ppm in a 29Si-MAS NMR spectrum, B is the intensity of peak B with a chemical shift value in the range of -20 ppm to -100 ppm in the 29Si-MAS NMR spectrum; and C is the intensity of peak C with a chemical shift value in the range of -110 ppm to -140 ppm in the 29Si-MAS NMR spectrum. The ratio can be, for example, 3.2 or greater and less than 4. In this document, in the case where peak A, peak B, or peak C includes two or more peaks, when calculating the ratio, the intensity of the corresponding peak is calculated as the sum of the intensities of the two or more peaks. For example, in the case where there are two peaks B, when calculating the ratio, the intensity of peak B is calculated as the sum of the intensities of the two peaks B'.

[046] In this descriptive report, the NMR spectrum of 29Si-MAS is a spectrum measured by a 400 MHz wideband (WB) NMR system and can be measured under the following conditions. MAS rate (magic angle rotation): 14 kHz Spectral frequency (sfo1): 79.51 MHz (29Si) Temperature: ambient temperature 29Si chemical shift reference: TMS (l) at 0 ppm Pulse program: 1D Hahn echo Spectral width (sw): 100 kHz Acquisition time: 40 ms Carrier frequency (o1p) at -40 ppm Pulse length (p1): 3 μs Recycle delay (d1): 60 s Number of scans: 1k to 5k

[047] 'Gaussian / Lorentzian' was selected as the fitting model to analyze a waveform measured using the method above. The parameters used Petition 870250085647, dated 09 / 22 / 2025, page 19 / 54 10 / 34 for analysis consists of peak amplitude, peak position, total peak width at half maximum, and Gaussian / Lorentzian fraction (xG / (1-x)L). After defining the appropriate initial values, the fitting was performed. At this point, xG / (1-x)L was fixed at 0.3 (xG / (1-x)L = 0.3). The fitting conditions used were nParVar = 15, Step = 1, and Thresh = 0.001, and the fitting was performed repeatedly until an appropriate convergence value was reached.

[048] In this descriptive report, a peak in the NMR-MAS-29Si spectrum refers to a peak with an intensity equal to or greater than 10% of the peak maximum intensity, and those with an intensity less than 10% of the peak maximum intensity are not included in the peak.

[049] Peak A, with a chemical shift value in the range of 20 ppm to -15 ppm in the NMR-MAS-29Si spectrum, refers to a silicon carbide (Si-C) peak, in which silicon and carbon are covalently bonded, and peak B, with a chemical shift value in the range of -20 ppm to -100 ppm, may refer to a peak of the element Si itself or of silicon oxide. A component represented by peak B may be represented as SiOx (x is 0 or greater and less than 2). For example, Si itself is a material that has a peak at or near -79 ppm; therefore, when peak B appears at or near -89 ppm, it can be determined to be Si or SiOx.

[050] The silicon-carbon composite also exhibits peak C, with a chemical shift value in the range of -110 ppm to -140 ppm in the NMRMAS-29Si spectrum. Peak C indicates the presence of SiO2. Peak C has technical importance because the battery capacity characteristics can be improved by ensuring that the (B + C) / A ratio described above has a specific value.

[051] The present inventors have found that peak B and peak C are advantageous in expressing the capacity of a battery, and peak A has an effect on improving water-based processability. Furthermore, the present inventors Petition 870250085647, dated 09 / 22 / 2025, page 20 / 54 11 / 34 found that when the ratio of these intensities is within a certain range, both battery capacity and water-based processability can be improved. According to one example, the ratio ((B + C) / A) of the sum of the intensities of peak B and peak C to the intensity of peak A is 3 or greater and less than 4. Within the above range, the battery exhibits excellent capacity and efficiency characteristics, and can exhibit excellent discharge capacity as an excellent silicon-based active material. Furthermore, within the above range, gas generation during a water-based process can be reduced, and the decomposition of components, such as a cellulose-based binder used in conjunction in the water-based process, can be avoided, thus maintaining phase stability and preventing a decrease in paste viscosity.

[052] According to an exemplary embodiment, the silicon-carbon composite can be represented by an active material based on Si / C. In the present report, the silicon-carbon composite is a composite of Si and C, distinguishing itself from silicon carbide itself, called SiC. Silicon carbide does not react electrochemically with lithium, therefore, all performance, including service life, can be measured as 0.

[053] In this descriptive report, the silicon-carbon composite is a composite of Si and C, where Si and C (e.g., graphite) are present, respectively. For example, a peak of Si and C can be observed by an elemental analysis method such as XRD or NMR. In this descriptive report, the silicon-carbon composite may be referred to as Si / C. The silicon-carbon composite may contain an additional component as needed. For example, the silicon-carbon composite may include silicon carbide, referred to as SiC. When the silicon-carbon composite includes silicon carbide, its content is 3% by weight or less. The silicon-carbon composite may be present in a crystalline, amorphous, or mixed state. According to one example, the C in the silicon composite Petition 870250085647, dated 09 / 22 / 2025, page 21 / 54 12 / 34 carbon can be present in an amorphous state.

[054] According to an exemplary embodiment, the silicon-carbon composite may comprise carbon in an amount of 38 parts by weight to 50 parts by weight, based on 100 parts by weight of the silicon-carbon composite. Specifically, the silicon-carbon composite may comprise carbon in an amount of 38 parts by weight to 50 parts by weight, 38 parts by weight to 45 parts by weight, or 38 parts by weight to 43 parts by weight, based on 100 parts by weight of the silicon-carbon composite.

[055] If the amount of carbon is below the range above, the exposure of silicon on the surface of the silicon-carbon composite increases, raising the possibility of side reactions with water, thus deteriorating aqueous processability. If the carbon exceeds the range above, the weight of silicon becomes relatively low, making it difficult to obtain the desired capacity.

[056] According to an exemplary embodiment, the silicon-carbon composite may be a particle that includes a porous carbon-silicon-based particle provided in at least a portion of an interior and a surface of the porous carbon-based particle; or a particle including a porous silicon-carbon-based particle provided in at least a portion of an interior and a surface of the porous silicon-based particle.

[057] According to an exemplary embodiment, the silicon-carbon composite is a particle comprising a porous carbon-silicon-based particle disposed in at least a portion of an interior and a surface of the porous carbon-based particle. The silicon can be formed by depositing silicon onto the porous carbon-based particle using silane gas. If necessary, a carbon layer can be additionally formed on the surface of the silicon-carbon composite. The carbon layer confers conductivity and improves the initial efficiency, lifetime characteristics, and capacity characteristics of the battery. Petition 870250085647, dated 09 / 22 / 2025, page 22 / 54 13 / 34 secondary. The total weight of the carbon layer can be from 5% by weight to 40% by weight, based on a total of 100% by weight of the silicon-carbon composite particles. The carbon layer can include at least one of amorphous carbon and crystalline carbon.

[058] According to an exemplary embodiment, the silicon-carbon composite can be manufactured by a method comprising: carrying out a disproportionality reaction by heat-treating a silicon oxide powder; etching the heat-treated silicon oxide powder with an etching agent; obtaining a silicon-based porous particle by pulverizing the etched silicon oxide powder; and forming a silicon-carbon composite by reacting the silicon-based porous particle with a carbon source to form a carbon layer on the surface of the silicon-based porous particle.

[059] According to another exemplary embodiment, the silicon-carbon composite can be manufactured by a method for preparing a silicon-carbon composite, the method comprising: depositing silicon onto a porous carbon particle by chemical vapor deposition, the method optionally further comprising forming a carbon layer on the surface of the silicon deposited on the porous carbon particle.

[060] According to an exemplary embodiment, the silicon-carbon composite may be a particle that includes a porous silicon-based particle and carbon present in at least a portion of an interior and a surface of the porous silicon-based particle. This may be formed by etching silicon oxide to form porous silicon-based particles, as a Si matrix, and then coating them with carbon. The carbon layer revelation described above may be applied to carbon.

[061] According to one example, porous silicon-based particles can be manufactured by phase separation of silicon oxide (e.g., SiO) Petition 870250085647, dated 09 / 22 / 2025, page 23 / 54 14 / 34 in Si and silicon dioxide (SiO2) by heat treatment and then by etching with an etching agent such as HF. By heat-treating the silicon oxide, the Si grain size corresponding to peak B can be controlled by a disproportionality reaction (900 to 1400°C). This makes it possible to adjust the ratio between peaks A, B, and C described above.

[062] According to an exemplary embodiment, the silicon-carbon composite may have a specific surface area of ​​0.5 to 10 m2 / g, measured by the BET method, a pore volume of 0.005 to 0.03 cm3 / g and a pore size of 10 to 20 nm, measured by the BET method. The silicon-carbon composite may have a pore volume of 0.005 to 0.03 cm3 / g, measured by the mercury penetration method (Hg porosimeter).

[063] According to an exemplary embodiment, the silicon-carbon composite may have a particle diameter D90 of 5 to 15 μm, a particle diameter D50 of 1 to 10 μm, a Dmin of 1 to 3 μm and a Dmax of 17 to 23 μm. In the present descriptive report, the average particle diameter (D50) may be defined as a particle diameter corresponding to 50% of the cumulative volume in the particle diameter distribution curve. The average particle diameter (D50) may be measured using, for example, a laser diffraction method. In the laser diffraction method, in general, particle diameters ranging from a submicrometer region to several millimeters may be measured, and results of high reproducibility and high resolvability may be obtained.

[064] An exemplary embodiment provides a negative electrode active material including the silicon-carbon composite, according to the exemplary embodiments described above.

[065] An exemplary embodiment provides a negative electrode composition including the negative electrode active material, according to the exemplary embodiment described above, a binder and a conductive material. Petition 870250085647, dated 09 / 22 / 2025, page 24 / 54 15 / 34

[066] According to an exemplary embodiment, the silicon-carbon composite may be included in an amount of 0.1 parts by weight to 14 parts by weight, for example, 0.1 parts by weight to 12 parts by weight, or 1 part by weight to 10 parts by weight, based on 100 parts by weight of the negative electrode active material.

[067] According to an exemplary embodiment, the negative electrode active material may further include a carbon-based active material. The carbon-based active material may be included in an amount of 86 parts by weight or more and 99.9 parts by weight or less, 88 parts by weight or more and 99.9 parts by weight or less, for example, 90 parts by weight to 99 parts by weight, based on a total of 100 parts by weight of the negative electrode active material included in the negative electrode composition. The carbon-based active material may include at least one of natural graphite and artificial graphite. When the carbon-based active material includes natural graphite and artificial graphite, the weight ratio of artificial graphite to natural graphite may be 1:99 to 99:1, for example, 1:9 to 9:1, or it may be 3:7 to 7:3.For example, based on 100 parts by weight of the carbon-based active material, the natural graphite content can be from 10 to 70 parts by weight, and the artificial graphite content can be from 30 to 90 parts by weight.

[068] Natural graphite refers to graphite that occurs naturally, and examples of this include flaky graphite, flaky graphite, or soil graphite. Natural graphite has the advantages of being abundant, having a low price, high theoretical capacity and compaction density, and being able to generate high yields.

[069] According to one example, spheroidized natural graphite can be used as natural graphite, and the degree of spheroidization can be 0.9 or more. According to one example, natural graphite can be spheroidized natural graphite and have a packed density of 0.9 g / cm3 or more.

[070] In this descriptive report, the degree of spheroidization can be, Petition 870250085647, dated 09 / 22 / 2025, page 25 / 54 16 / 34 when a particle is projected, a value obtained by dividing the circumference of a circle with the same area as the projected image by the circumferential length of the projected image. The degree of spheroidization can be obtained from a SEM image or, alternatively, it can be measured using a particle shape analyzer, such as the Sysmex FPIA3000, available from Malvern. Additionally, the crystal size can be confirmed by XRD analysis.

[071] According to an exemplary embodiment of the present description, the composition of the negative electrode may further include a ligand and a conductive material, and the ligand may be an aqueous ligand.

[072] The binder may include at least one selected from the group consisting of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-coHFP), polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluorinated rubber, polyacrylic acid and the above-mentioned materials in which a hydrogen is replaced by Li, Na, Ca, etc., and may also include their various copolymers.

[073] The conductive material is not particularly limited, provided it has conductivity without causing chemical alteration in the battery, and for example, graphite, such as natural graphite or artificial graphite; carbon black, such as acetylene black, Ketjen black, channel black, furnace black, lamp black and thermal black; a conductive fiber, such as carbon fiber and metallic fiber; a conductive tube, such as carbon nanotube; fluorocarbon powder, metallic powder, such as aluminum powder and nickel powder; a conductive fiber, such as zinc oxide and potassium titanate; a conductive metallic oxide, such as titanium oxide; a conductive material, such as a polyphenylene derivative, and the like may be used. Petition 870250085647, dated 09 / 22 / 2025, p. 26 / 54 17 / 34

[074] According to an exemplary embodiment, the aqueous binder is included in an amount of 1 to 5% by weight, for example, about 3 to 4% by weight based on the solids content of the negative electrode composition, and the conductive material is included in an amount of 0.1 to 2% by weight, for example, about 1% by weight, based on the solids content of the negative electrode composition.

[075] An exemplary embodiment of the present disclosure provides a negative electrode including the negative electrode composition according to the exemplary embodiments described above.

[076] Specifically, the negative electrode may include a negative electrode current collector and a layer of negative electrode active material disposed on at least one surface of the negative electrode current collector. The layer of negative electrode active material includes the negative electrode composition according to the exemplary embodiments described above.

[077] The negative electrode active material layer can be formed by applying a negative electrode paste, including the negative electrode composition described above, to at least one surface of a negative electrode current collector, and drying and pressing the surface by roller.

[078] The negative electrode current collector is not particularly limited, provided it has conductivity without causing chemical alteration in the battery. For example, for the current collector, copper, stainless steel, aluminum, nickel, titanium, burnt carbon, aluminum or stainless steel can be used, with each surface treated with carbon, nickel, titanium, silver or similar. Specifically, transition metals that adsorb carbon well, such as copper and nickel, can be used for the current collector. The thickness of the current collector can be from 6 μm to 20 μm. However, the thickness of the current collector is not limited to this.

[079] The negative electrode paste may include a solvent for the formation of the negative electrode paste. Specifically, the solvent for the formation of the paste Petition 870250085647, dated 09 / 22 / 2025, page 27 / 54 18 / 34 of the negative electrode may include at least one selected from the group consisting of distilled water, ethanol, methanol, and isopropyl alcohol, and specifically distilled water, in terms of facilitating the dispersion of the components.

[080] An exemplary embodiment of the present disclosure provides a lithium secondary battery including the negative electrode according to the exemplary embodiment described above, a positive electrode and a separator.

[081] The positive electrode may include a positive electrode current collector and a layer of positive electrode active material formed over the positive electrode current collector and including the positive electrode active material.

[082] In the positive electrode, the positive electrode current collector is not particularly limited, provided it has conductivity without causing a chemical change in the battery. For example, stainless steel, aluminum, nickel, titanium, burnt carbon, aluminum or stainless steel, each with a surface treated with carbon, nickel, titanium, silver or similar materials, can be used. In addition, the positive electrode current collector can typically have a thickness of 3 to 500 μm, and the surface of the current collector can be formed with microscopic irregularities to increase the adhesive strength of the active material of the positive electrode. For example, the positive electrode current collector can be used in various forms such as film, sheet, blade, mesh, porous body, foamed body and nonwoven fabric body.

[083] The active material of the positive electrode may be a typically used active material of the positive electrode. Specifically, the active material of the positive electrode may be a layered compound, such as lithium-cobalt oxide (LiCoO2) and lithium-nickel oxide (LiNiO4), or a compound substituted with one or more transition metals; a lithium-iron oxide, such as LiFe3O4; a lithium-manganese oxide, such as the chemical formula Lii+ClMn2-ClO4 (0 <c1<0.33), LiMnO3, LiMn?O3 e LiMnO?; um óxido de lítio-cobre (Li2CuO2); um óxido de vanádio, tal como LiV3O8, V2O5 e Cu?V?O7; um óxido de lítio-níquel do tipo Ni-site representado pela fórmula química LiNii-c2Mc2O2 (onde M Petition 870250085647, dated 09 / 22 / 2025, p. 28 / 54 19 / 34 is at least one selected from the group consisting of Co, Mn, Al, Cu, Fe, Mg, B, and Ga, and satisfies 0.01 <c2<0,3); um óxido composto de lítio-manganês representado pela fórmula química LiMn2-c3Mc3O2 (onde M é pelo menos um selecionado do grupo que consiste em Co, Ni, Fe, Cr, Zn e Ta, e satisfaz 0,01<c3<0,1) ou Li2Mn3MO8 (onde M é pelo menos um selecionado do grupo que consiste em Fe, Co, Ni, Cu e Zn); LiMn2O4 em que uma parte do Li da fórmula química é substituída por um íon de metal alcalinoterroso, ou similar, mas não se limita a isso. O eletrodo positivo pode ser metal Li.

[084] The active material layer of the positive electrode may include a positive electrode conductive material and a positive electrode binder, along with the positive electrode active material described above.

[085] In this case, the conductive material of the positive electrode is used to impart conductivity to the electrode and can be used without specific limitation, provided that the conductive material of the positive electrode has electronic conductivity without causing a chemical change in the battery to be constructed. Specific examples may include graphite, such as natural graphite and artificial graphite; a carbon-based material, such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black and carbon fiber; metallic powders or metallic fibers, such as copper, nickel, aluminum and silver; a conductive fiber, such as zinc oxide and potassium titanate; a conductive metallic oxide, such as titanium oxide; or a conductive polymer, such as a polyphenylene derivative or similar, any one of these or a mixture of two or more may be used.

[086] In addition, the positive electrode ligand serves to improve the bond between the particles of the positive electrode active material and the adhesive force between the positive electrode active material and the positive electrode current collector. Specific examples may include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, cellulose Petition 870250085647, dated 09 / 22 / 2025, page 29 / 54 20 / 34 regenerated, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluorinated rubber or various copolymers thereof and the like, and any one of these or a mixture of two or more may be used.

[087] The separator serves to separate the negative electrode from the positive electrode and to provide a migration path for lithium ions, in which any separator can be used as a separator, without specific limitation, provided it is typically used in a secondary battery. In particular, a separator with high moisture retention capacity for an electrolyte solution, as well as low resistance to the movement of electrolyte ions, may preferably be used. Specifically, a porous polymer film, for example, a porous polymer film made from a polyolefin-based polymer, such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer and an ethylene / methacrylate copolymer, or a laminated structure with two or more layers of these, may be used.In addition, a common porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fibers, polyethylene terephthalate fibers or similar, can be used. Furthermore, a coated separator including a ceramic component or polymeric material can be used to ensure heat resistance or mechanical strength, and a separator with a single-layer or multi-layer structure can be selectively used.

[088] The secondary lithium battery may also include an electrolyte. Examples of electrolytes may include an organic liquid electrolyte, an inorganic liquid electrolyte, a solid polymer electrolyte, a gel-type polymer electrolyte, a solid inorganic electrolyte, or a molten-type inorganic electrolyte, which may be used in the manufacture of the secondary lithium battery, but are not limited to these.

[089] Specifically, the electrolyte may include a non-organic solvent Petition 870250085647, dated 09 / 22 / 2025, page 30 / 54 21 / 34 aqueous and a metallic salt.

[090] As a non-aqueous organic solvent, an aprotic organic solvent may be used, for example, such as N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butyrolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxyethane, dioxolane derivative, sulfolane, methylsulfolane, 1,3-dimethyl2-imidazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, ether, methyl propionate or ethyl propionate.

[091] In particular, among carbonate-based organic solvents, ethylene carbonate and propylene carbonate, which are cyclic carbonates, are high-viscosity organic solvents and may be preferentially used because they exhibit high permittivity for dissociating a lithium salt well. When the cyclic carbonate is mixed with a low-viscosity, low-permittivity linear carbonate, such as dimethyl carbonate and diethyl carbonate, in a suitable ratio and used, an electrolyte with high electrical conductivity can be prepared and, therefore, such combined use may be more preferable.

[092] A lithium salt can be used as a metallic salt, and the lithium salt is a readily soluble material in non-aqueous electrolytic solution, in which, for example, one or more selected from the group consisting of F-, Cl-, I', NO3-, N(CN)2-, BF4-, ClO4-, PF6-, (CF3)2PF4-, (CF3)3PF3-, (CF3>PF2-, (CF3)5PF-, (CF3)6P-, CF3SO3-, CF3CF2SO3-, (CF3SO2)2N-, (FSO2)2N-, CF3CF2(CF3)2CO-, (CF3SO2)2CH-, (SF5)3C-, (CF3SO2)3C-, CF3(CF2)7SO3-, CF3CO2-, CH3CO2-, SCN- and (CF3CF2SO2)2N- can be used as lithium salt anion.

[093] One or more additives, for example, a haloalkylene carbonate-based compound, such as difluoroethylene carbonate, pyridine, triethylphosphite, triethanolamine, Petition 870250085647, dated 09 / 22 / 2025, page 31 / 54 22 / 34 cyclic ether, ethylenediamine, n-glyme, hexamethyl phosphoric triamide, a nitrobenzene derivative, sulfur, a quinone imine dye, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, an ammonium salt, pyrrole, 2-methoxyethanol or aluminum trichloride, may be additionally included in the electrolyte for the purpose of improving battery life characteristics, suppressing a decrease in battery capacity, improving battery discharge capacity and the like, in addition to the electrolyte components described above.

[094] Another exemplary embodiment of the present disclosure provides a battery module including the secondary battery as a unit cell and a battery pack including the same. As the battery module and battery pack include the secondary battery with high capacity, high rate capacity and high cycle characteristics, the battery module and battery pack can be used as a power source for a medium to large-sized device selected from the group consisting of an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle and an energy storage system. Method of carrying out the invention

[095] The Examples described herein will be described in detail to specifically illustrate the present descriptive report. However, the Examples in accordance with the present descriptive report may be modified in other ways, and the scope of the present application is not limited to the Examples below. The Examples in the present application are provided to explain the present descriptive report more specifically to one versed in the field. Example 1 (1) Preparation of Carbon and Silicon Composite

[096] A disproportionation reaction of SiO was caused by the heat treatment of 20 g of SiOx powder (x = 0.9 to 1) at 1200°C in an inert argon gas atmosphere. Petition 870250085647, dated 09 / 22 / 2025, page 32 / 54 23 / 34

[097] After 10 g of the treated SiOx powder (x = 0.9 to 1) had been dispersed in distilled water, 10 mL of a 30% by weight aqueous HF solution were slowly added, stirring the dispersion solution at a speed of 500 RPM. The SiO powder obtained by the above process was attacked for 2 hours. The pH of the powder was neutralized by filtration or washing after the above preparation process. The resulting powder was subjected to a drying process at 130°C for 6 hours under vacuum to prepare porous silicon. Subsequently, pulverization was carried out with a pestle and mortar, so that the particle size was D50 from 4 to 6 μm. Next, a silicon-carbon composite containing a carbon layer was prepared by reacting porous silicon with acetylene (C2H2) at 1 L / min, 10-1 torr, and 720°C for approximately 5 hours under an inert gas atmosphere, Ar, using a CVD apparatus to form a carbon layer on the surface of the porous silicon.The result of the NMR analysis is shown in Figure 1. According to Figure 1, peaks corresponding to peaks A, B, and C appeared, and the ratio (B + C) / A was measured as 3.3. (2) Preparation of the Negative Electrode

[098] A negative electrode paste was prepared by mixing an active material for the negative electrode, including the prepared silicon-carbon composite and graphite, in a 9:91 weight ratio; a conductive material, including carbon black and SWCNT; and a binder, including carboxymethylcellulose (CMC) and styrene-butadiene rubber (SBR), in a 95.3:1:3.6 weight ratio, and adding an appropriate amount of distilled water, so that the total solids content was about 46% by weight.

[099] The negative electrode paste was applied to a thin Cu metal film approximately 20 μm thick, which was then dried at a circulating air temperature of 60°C. The thin film was then roller-pressed, dried in a vacuum oven at 130°C for approximately one day, and punched into a circular shape of 1.4875 cm2 to prepare a negative electrode. Petition 870250085647, dated 09 / 22 / 2025, page 33 / 54 24 / 34 (3) Secondary Battery Preparation

[0100] A thin film of Li metal punched with 1.7671 cm2 was used as the positive electrode. A Li coin cell was prepared by interposing a porous polyethylene separator between the positive and negative electrodes and injecting an electrolyte solution in which 1 M LiPF6 was dissolved in a mixed solution prepared by mixing EMC (methyl ethyl carbonate) and EC (ethylene carbonate) in a 7:3 ratio, with the addition of an additive. Example 2

[0101] A silicon-carbon composite was prepared in the same manner as in Example 1, except that the temperature of the disproportionality reaction was adjusted to 1150°C and the carbon layer was prepared by reacting porous silicon with acetylene (C2H2) at 700°C. A result of the NMR analysis of the active material prepared by the method of Example 2 is shown in Figure 2. According to Figure 2, peaks corresponding to peaks A, B, and C appeared, and the ratio (B + C) / A was measured to be 3.5.

[0102] Using the prepared silicon-carbon composite, a negative electrode and a secondary battery were prepared in the same way as in Example 1.

[0103] Figure 8 shows the waveform analysis result from the NMR analysis result of Figure 2. The silicon-carbon composite of Example 2 presents peaks (1) to (6), in which peak (1) corresponds to peak A, peaks (2), (4), (5) and (6) correspond to peak B, and peak (3) corresponds to peak C. When calculating the ratio (B + C) / A, B was calculated as the sum of the intensities of peaks (2), (4), (5) and (6). Example 3 (1) Preparation of Porous Carbon Particles

[0104] A 0.5 M aqueous sucrose solution was placed in a Petition 870250085647, dated 09 / 22 / 2025, pp. 34 / 54 25 / 34 autoclave and subjected to a reaction at 180°C for 24 hours to synthesize spherical particles. The carbon-based particles obtained after the reaction were washed with ethanol 3 to 5 times. The carbon-based particles, dried at 100°C for 24 hours or more, were mixed with KOH in a 1:3 ratio by weight, and the mixture was heated to 800°C for 3 hours in a nitrogen atmosphere to expand the pores. Then, the resulting material was washed with distilled water and dried at 80°C for 12 hours or more to prepare porous carbon particles. (2) Silicon Deposition and Carbon Composition

[0105] A negatively charged active material in the form of silicon deposited on porous carbon particles was prepared by injecting silane gas into a chemical vapor deposition (CVD) reactor at a flow rate of about 40 to 110 mL / min, and processing for about 3 hours at temperatures below 800°C with a temperature increase of 10 to 15°C / min. Subsequently, a silicon-carbon composite was prepared by reacting the silicon-containing porous carbon particles with ethylene gas (C2H4) at 1 L / min, 10-1 torr, and 700°C for about 5 hours under an inert gas and Ar atmosphere, using a CVD apparatus to form a carbon layer on the surface of the silicon active material. As a result of the NMR analysis of the silicon-carbon composite prepared in this way, according to Figure 3, peaks corresponding to peaks A, B and C appeared, and the ratio (B + C) / A was measured to be 3.4. (3) Preparation of the Negative Electrode and the Secondary Battery

[0106] Using the prepared silicon-carbon composite, an active material for the negative electrode was prepared, including the prepared silicon-carbon composite and graphite in a mass ratio of 12:88, and a negative electrode and a secondary battery were prepared in the same manner as in Example 1. Comparative Example 1 (1) Method for Preparing Magnesium-Containing Silicon Oxide Petition 870250085647, dated 09 / 22 / 2025, page 35 / 54 26 / 34

[0107] Si and SiO2 were mixed in a 1:1 molar ratio in crucible no. 1 and heated to a sublimation temperature of 1400°C. In crucible no. 2, metallic magnesium was heated separately to 600–1000°C and evaporated. All crucibles were depressurized to 0.1 torr. The vaporous mixture containing Mg obtained from crucible no. 1 and crucible no. 2 was reacted for 6 hours and then condensed to a solid phase in a vacuum region of 800°C. The silicon-based active material prepared by the above method was pulverized for 3–4 hours using a ball mill to prepare particles with a D50 of approximately 6 μm. Subsequently, a magnesium-containing silicon oxide was prepared by reacting the particles with methane (CH4) at 1 L / min. at 10-1 torr for approximately 5 hours under an atmosphere of inert gas and Ar, using a CVD apparatus to form a carbon layer on the surface of the silicon-based active material.The Mg content in the powder was analyzed by ICP-MS and measured to be 8% by weight.

[0108] As a result of the NMR analysis of the silicon oxide prepared by the method, according to Figure 4, peaks corresponding to peaks B and C appeared, peak A did not appear, and the ratio (B + C) / A was not measurable because there was no peak A.

[0109] Using the prepared silicon-carbon composite, a negative electrode active material was prepared to include the prepared silicon-carbon composite and graphite in a mass ratio of 15:85, and a negative electrode and a secondary battery were prepared in the same manner as in Example 1. Comparative Example 2

[0110] iA silicon oxide was prepared by the same method as in Comparative Example 1, except that the active material was prepared without metallic magnesium in crucible no. 2 of Comparative Example 1. As a result of the NMR analysis of the silicon oxide prepared by the method, according to Figure 4, peaks corresponding to peaks B and C appeared, peak A did not appear, and the ratio (B + C) / A was not Petition 870250085647, dated 09 / 22 / 2025, page 36 / 54 27 / 34 measurable because there was no peak A

[0111] Using the prepared silicon-carbon composite, a negative electrode active material was prepared to include the prepared silicon-carbon composite and graphite in a mass ratio of 12:88, and a negative electrode and a secondary battery were prepared in the same manner as in Example 1. Comparative Example 3

[0112] The same method as in Example 3 was performed, except that the temperature of the CVD carbon coating process, performed for porous carbon using ethylene (C2H4) in Example 3, was adjusted to 500°C. As a result of the NMR analysis of the silicon-carbon composite prepared in this way, according to Figure 5, peaks corresponding to peaks B and C appeared, peak A did not appear, and the ratio (B + C) / A was not measurable because there was no peak A.

[0113] Using the prepared silicon-carbon composite, a negative electrode and a secondary battery were prepared in the same manner as in Example 1. Comparative Example 4

[0114] A gaseous mixture of 1 L / min. of silane, 3 L / min. of acetylene and 1 L / min. of argon was introduced into a deposition chamber of a fluidized bed reactor at a temperature of 700°C and a pressure of 1 atm. A silicon-carbon composite was obtained in the collection chamber of the fluidized bed reactor. As a result of the NMR analysis of the silicon-carbon composite prepared in this way, peaks corresponding to peaks A, B and C appeared, and the ratio (B + C) / A was measured as 2.8.

[0115] Using the prepared silicon-carbon composite, an active material for the negative electrode was prepared, including the prepared silicon-carbon composite and graphite in a mass ratio of 11:89, and a negative electrode and a secondary battery were prepared in the same manner as in Example 1. Petition 870250085647, dated 09 / 22 / 2025, page 37 / 54 28 / 34 Comparative Example 5

[0116] Quantities of 1 kg of silicon powder and 1 kg of silica powder were placed in a vacuum reactor, and a vacuum was initially created at 0.1 torr or less. The materials were then heated to 1400°C, converting them into vapor. Simultaneously, a benzene solution was slowly passed through, causing the benzene to vaporize rapidly. After complete mixing of the benzene vapor with the vapor of the silicon / silica mixture, the mixed vapor was cooled and deposited onto a water-cooled substrate. The resulting material was ground to obtain silicon oxide, in which carbon atoms were uniformly inserted at the atomic level. The ground material was then coated with carbon, and 1 kg of the material was placed in a rotary kiln, heated to 1000°C under an argon shielding gas atmosphere.A mixed gas of argon and equal amounts of propylene and methane were introduced in a 1:1 volume ratio for the vapor coating, with a 2:3 volume ratio of propylene to methane. After maintaining the temperature for 1 hour and stopping the supply of organic gas, the material was cooled to obtain silicon oxide, in which the carbon atoms were uniformly dispersed at the atomic level. As a result of the NMR analysis of the silicon-carbon composite prepared in this way, according to Figure 1, peaks corresponding to peaks B and C appeared, peak A did not appear, and the ratio (B + C) / A was not measurable because there was no peak A.

[0117] Using the prepared silicon-carbon composite, a negative electrode active material was prepared to include the prepared silicon-carbon composite and graphite in a mass ratio of 12:88, and a negative electrode and a secondary battery were prepared in the same manner as in Example 1. Comparative Example 6

[0118] A silicon-carbon composite was prepared by the same method as in Example 3, except that the silane gas injection time in Example 3 was set Petition 870250085647, dated 09 / 22 / 2025, pp. 38 / 54 29 / 34 as 5 hours. As a result of the NMR analysis of the silicon-carbon composite prepared by the method, according to Figure 6, peaks corresponding to peaks A, B and C appeared, there were no peaks from -205 ppm to -300 ppm, and the ratio (B + C) / A was measured as 2.7.

[0119] Using the prepared silicon-carbon composite, a negative electrode and a secondary battery were prepared in the same manner as in Example 1. Comparative Example 7

[0120] A silicon-carbon composite was prepared by the same method as Example 3, except that carbon-based particles and KOH were mixed in a weight ratio of 1:3.5 and heat-treated for 5 hours in the pore expansion process of the porous carbon, reacting at 650°C for 8 hours under a silane gas deposition process at a flow rate of 300 mL / min. As a result of the NMR analysis of the silicon oxide prepared by the method, according to Figure 7, peaks corresponding to peaks A, B, and C appeared, and the ratio (B + C) / A was measured as 2.6.

[0121] Using the prepared silicon-carbon composite, a negative electrode active material was prepared to include the prepared silicon-carbon composite and graphite in a weight ratio of 10:90, and a negative electrode and a secondary battery were prepared in the same manner as in Example 1.

[0122] The ratios between the peaks specified by NMR analysis of the silicon-based active materials prepared in the Examples and Comparative Examples are shown in Table 1 below.

[0123] In addition, the C, O, and Si contents of each sample and comparative sample were measured using a carbon-sulfur analyzer (CS Analyzer) and an oxygen-nitrogen-hydrogen analyzer (ONH Analyzer), and the proportion of graphite included in the negative active material is shown in Table 2 below. Petition 870250085647, dated 09 / 22 / 2025, page 39 / 54 30 / 34 Battery Performance Evaluation

[0124] The prepared batteries were charged and discharged to evaluate discharge capacity, initial efficiency and capacity retention rate, and the evaluation results are shown in Table 1 below.

[0125] Charging and discharging were performed at 0.1°C in the first and second cycles, and charging and discharging were performed at 0.5°C from the third to the 49th cycle. In the 50th cycle, charging and discharging were terminated in the charged state (with lithium contained in the negative electrode).

[0126] Load conditions: DC (constant current) / CV (constant voltage) (current cutoff of 5 mV / 0.005°C)

[0127] Discharge conditions: DC (constant current) condition 1.5 V

[0128] The discharge capacity (mAh / g) and initial efficiency (%) were derived from the result after the first charge and discharge. Specifically, the initial efficiency (%) was derived by the following calculation:

[0129] Initial efficiency (%) = (first discharge capacity / first load capacity) χ 100%

[0130] The capacity retention rate was derived by the following calculation.

[0131] Capacity retention rate (%) = (discharge capacity on the 49th time / discharge capacity on the first time) χ 100% Water-Based Processability Assessment 1) Evaluation of Processability Characteristics (shear viscosity)

[0132] As part of the processability assessment, the amounts of variation in shear viscosity at a shear rate = 1 Hz of a paste prepared in the Examples and Comparative Examples are shown in Table 2 below. Specifically, the amount of variation (%) in shear viscosity was derived by the following calculation formula. Petition 870250085647, dated 09 / 22 / 2025, pages 40 / 54 31 / 34

[0133] Amount of variation (%) in shear viscosity = ((shear viscosity of the paste after 48 h - shear viscosity of the paste immediately after mixing) / shear viscosity of the paste immediately after mixing) * 100% 2) Gas Generation Timing

[0134] After 20 g of paste were placed in a 10 x 15 cm aluminum bag and vacuum sealed, a volume change was measured using Archimedes' principle, and a moment at which a volume change of 2 mL or more occurred at 60°C was defined as a gas generation moment. Table 1 NMR Battery Ratio of (B + C) / A Discharge Capacity (mAh / g) Initial Efficiency (%) Capacity Retention Rate (%) 100 Cycles Amount of Change (%) in Shear Viscosity Momentum of Gas Generation (day) Example 1 3.3 494 90 92 0 8 Example 2 3.5 489 89 90 0 8 Example 3 3.4 445 89 86 20 7 Comparative Example 1 - 445 86 85 2 7 Comparative Example 2 - 455 85 82 2 7 Comparative Example 3 - 460 85 80 60 1 Comparative Example 4 2.8 513 89 82 40 2 Comparative Example 5 - 463 87 81 2 7 Petition 870250085647, dated 09 / 22 / 2025, pages 41 / 54 32 / 34 NMR Battery Ratio of (B + C) / A Discharge capacity (mAh / g) Initial efficiency (%) Capacity retention rate (%) 100 cycles Amount of variation (%) in shear viscosity Momentum of gas generation (day) Comparative example 6 2.7 483 89 89 20 1 Comparative example 7 2.6 490 90 90 40 2 Table 2 Carbon content (%) based on silicon-carbon composite Oxygen content (%) based on silicon-carbon composite Silicon content (%) based on silicon-carbon composite Weight ratio of silicon-carbon composite to graphite Example 1 38.6 1.2 60.2 9:91 Example 2 43 0.4 56.6 9:91 Example 3 54 1.0 45 12:88 Comparative example 1 (Mg content: 8%) 3.5 30.9 57.6 15:85 Comparative example 2 3.5 34.0 62.5 12:88 Comparative example 3 52 1.2 46.8 9:91 Comparative example 4 55 1 44 11:89 Comparative example 5 0.9 35.5 63.6 12:88 Comparative example 6 50.6 1.4 48 9:91 Petition 870250085647, dated 09 / 22 / 2025, pages 42 / 54 33 / 34 Carbon content (%) based on silicon-carbon composite Oxygen content (%) based on silicon-carbon composite Silicon content (%) based on silicon-carbon composite Weight ratio of silicon-carbon composite to graphite Comparative example 7 51.3 1.1 46.9 10:90

[0135] In Examples 1 to 3, materials with peaks corresponding to peaks A, B, and C and meeting the peak ratio covered by the scope of the present disclosure were applied to the battery. As shown in Table 1, although certain or more effects were achieved in terms of discharge capacity, initial efficiency, and capacity retention rate, the viscosity variation and gas generation remained below a certain level.

[0136] In the case of Example 3, they showed inferior effects in terms of aqueous processability compared to Examples 1 and 2. This is because the silicon was deposited not only in the pores of the porous carbon, but also on the surface, which is disadvantageous for aqueous processability. However, it can be confirmed that they are superior in terms of capacity and aqueous processability compared to Comparative Examples 3, 6 and 7, which were produced by similar deposition of silicon on porous carbon, but did not reach the peak ratio.

[0137] On the other hand, Comparative Examples 1 to 7 did not reach the peak ratio, resulting in inferior effects on both capacity and aqueous processability. Specifically, in Comparative Examples 1, 2, and 5, an adequate amount of SiC was not generated, therefore peak A did not appear in the NMR analysis. Consequently, aqueous processability was poor due to reactions with the electrolyte.

[0138] In Comparative Example 4, the carbon content in the silicon-carbon composite was very high, causing the silicon surface to be exposed and Petition 870250085647, dated 09 / 22 / 2025, pages 43 / 54 34 / 34 resulting in side reactions with water, which led to inferior aqueous processability. Petition 870250085647, dated 09 / 22 / 2025, pages 44 / 54

Claims

1 / 4 CLAIMS 1. Silicon-carbon composite satisfying the condition 3 < ((B + C) / A) < 4, CHARACTERIZED in that A is an intensity of peak A with a chemical shift value in the range of 20 ppm to -15 ppm, in a 29Si-MAS NMR spectrum, B is an intensity of peak B with a chemical shift value in the range of -20 ppm to -100 ppm in the 29Si-MAS NMR spectrum; and C is an intensity of peak C with a chemical shift value in the range of -110 ppm to -140 ppm in the 29Si-MAS NMR spectrum.

2. Silicon-carbon composite according to claim 1, CHARACTERIZED in that the silicon-carbon composite comprises carbon in an amount of 38 parts by weight to 50 parts by weight, based on 100 parts by weight of the silicon-carbon composite.

3. Silicon-carbon composite according to claim 1, CHARACTERIZED in that the silicon-carbon composite is a particle comprising a porous carbon-silicon-based particle arranged in at least a portion of an interior and a surface of the porous carbon-based particle, or a particle comprising a porous silicon-carbon-based particle arranged in at least a portion of an interior and a surface of the porous silicon-based particle.

4. Silicon-carbon composite according to claim 1, CHARACTERIZED in that the silicon-carbon composite further comprises a carbon layer formed on a surface of the silicon-carbon composite, wherein the total weight of the carbon layer is from 5% by weight to 40% by weight, based on 100% by weight of the silicon-carbon composite.

5. Silicon-carbon composite according to claim 1, CHARACTERIZED in that the silicon-carbon composite has a pore volume of 0.005 to 0.03 cm3 / g. Petition 870250085647, dated 09 / 22 / 2025, page 45 / 54 2 / 4 6. Silicon-carbon composite according to claim 1, CHARACTERIZED in that the silicon-carbon composite has a pore size of 10 nm to 20 nm.

7. Silicon-carbon composite according to claim 1, CHARACTERIZED in that the silicon-carbon composite has a particle diameter D90 of 5 to 15 μm, a particle diameter D50 of 1 to 10 μm, a Dmin of 1 to 3 μm and a Dmax of 17 to 23 μm.

8. Active negative electrode material according to any one of claims 1 to 7, CHARACTERIZED in that it comprises a silicon-carbon composite.

9. Negative electrode active material according to claim 8, CHARACTERIZED in that the negative electrode active material comprises a silicon-carbon composite in an amount of 0.1 parts by weight to 14 parts by weight, based on 100 parts by weight of the negative electrode active material.

10. Negative electrode active material according to claim 8, CHARACTERIZED in that the negative electrode active material further includes a carbon-based active material, and in that the carbon-based active material is included in an amount of 86 parts by weight or more and 99.9 parts by weight or less based on 100 parts by weight of the negative electrode active material.

11. Negative electrode composition, CHARACTERIZED in that it comprises: the active material of the negative electrode according to claim 8; a binder; and a conductive material. Petition 870250085647, dated 09 / 22 / 2025, pp. 46 / 54 3 / 4 12. Negative electrode composition according to claim 11, CHARACTERIZED in that the active material of the negative electrode further comprises a carbon-based active material.

13. Negative electrode according to claim 11, CHARACTERIZED in that it comprises the composition of a negative electrode.

14. Secondary lithium battery, CHARACTERIZED in that it comprises: the negative electrode according to claim 13; a positive electrode; and a separator.

15. Battery module according to claim 14, CHARACTERIZED in that it comprises a secondary lithium battery.

16. Battery pack according to claim 14, CHARACTERIZED in that it comprises a secondary lithium battery.

17. Battery pack according to claim 15, CHARACTERIZED in that it comprises the battery module.

18. Method for preparing a silicon-carbon composite, the method CHARACTERIZED in that it comprises: carrying out a disproportionation reaction by heat treatment of a silicon oxide powder; etching the heat-treated silicon oxide powder with an etching agent; obtaining a silicon-based porous particle by spraying the etched silicon oxide powder; and forming a silicon-carbon composite by reacting the silicon-based porous particle with a carbon source to form a carbon layer on the surface of the silicon-based porous particle, Petition 870250085647, dated 09 / 22 / 2025, p.47 / 54 4 / 4 wherein the silicon-carbon composite satisfies the condition 3 < ((B + C) / A) < 4, wherein A is an intensity of peak A with a chemical shift value in the range of 20 ppm to -15 ppm in a 29Si-MAS NMR spectrum, B is an intensity of peak B with a chemical shift value in the range of -20 ppm to -100 ppm in the 29Si-MAS NMR spectrum; and C is an intensity of peak C with a chemical shift value in the range of -110 ppm to -140 ppm in the 29Si-MAS NMR spectrum.

19. Method for preparing a silicon-carbon composite, the method CHARACTERIZED in that it comprises: depositing silicon onto a porous carbon particle by chemical vapor deposition, wherein the method further optionally comprises forming a carbon layer on a surface of the silicon deposited onto the porous carbon particle, wherein the silicon-carbon composite satisfies the condition 3 < ((B + C) / A) < 4, wherein A is an intensity of peak A with a chemical shift value in the range of 20 ppm to -15 ppm in a 29Si-MAS NMR spectrum, B is an intensity of peak B with a chemical shift value in the range of -20 ppm to -100 ppm in the 29Si-MAS NMR spectrum; and C is an intensity of peak C with a chemical shift value in the range of -110 ppm to -140 ppm in the 29Si-MAS NMR spectrum. Petition 870250085647, dated 09 / 22 / 2025, pages 48 / 54

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