KR-20260068006-A - NEGATIVE ELECTRODE ACTIVE MATERIAL, MANUFACTURING METHOD OF NEGATIVE ELECTRODE ACTIVE MATERIAL, NEGATIVE ELECTRODE COMPOSITION, NEGATIVE ELECTRODE FOR LITHIUM SECONDARY BATTERY COMPRISING SAME, AND LITHIUM SECONDARY BATTERY COMPRISING NEGATIVE ELECTRODE

Abstract

The present application relates to a negative electrode active material, a method for manufacturing a negative electrode active material, a negative electrode composition, a negative electrode for a lithium secondary battery comprising the same, and a lithium secondary battery comprising the negative electrode.

Inventors

• 김태호
• 양현진
• 이승관
• 신선영
• 이용주

Assignees

• 주식회사 엘지에너지솔루션

Dates

Publication Date

20260513

Application Date

20251104

Priority Date

20241104

Claims (14)

1. A negative electrode active material comprising a silicon carbon composite comprising porous carbon; and silicon deposited on the porous carbon, The above silicon-carbon composite is a negative electrode active material having a time constant (T1) of 150 to 1000 when fitting the graph of etching time (x-axis) vs. C/Si ratio (y-axis) using an exponential decay function via XPS depth analysis.
2. In claim 1, A negative electrode active material comprising a carbon coating layer further comprising the surface of the above silicon carbon composite.
3. In claim 1, A negative electrode active material in which the silicon is 40 parts by weight or more and 60 parts by weight or less, based on 100 parts by weight of the silicon carbon composite.
4. In claim 1, The above silicon carbon composite is a negative electrode active material having an average particle size (D50) of 5 μm or more and 20 μm or less.
5. In claim 1, The above-mentioned negative electrode active material is a negative electrode active material that further comprises a carbon-based active material.
6. In claim 1, A negative electrode active material comprising 80 parts by weight or less of the silicon carbon composite based on 100 parts by weight of the above negative electrode active material.
7. A method for manufacturing a negative electrode active material comprising the step of forming a silicon-carbon composite by depositing silicon on porous carbon, In the step of forming a silicon-carbon composite by depositing silicon on the porous carbon, the deposition temperature is 500°C or higher and 800°C or lower, and the silicon flow rate is 50 ml/min to 250 ml/min. A method for manufacturing a negative electrode active material in which the above silicon carbon composite has a time constant (T1) of 150 to 1000 when fitting the graph of etching time (x-axis) vs. C/Si ratio (y-axis) by XPS depth analysis with an exponential decay function.
8. In claim 7, The above porous carbon has a ratio of 80% or more of first pores having a diameter of less than 2 nm when measured by the nitrogen adsorption method, and A method for manufacturing a negative electrode active material in which the above-mentioned porous carbon has a ratio of 20% or less of a second pore having a diameter of 2 nm or more and 50 nm or less when measured by nitrogen adsorption method.
9. In claim 7, A method for manufacturing a negative electrode active material, wherein the deposition pressure in the step of forming a silicon-carbon composite by depositing silicon on the porous carbon is 0.1 Torr or more and 15 Torr or less.
10. A cathode composition comprising a cathode active material according to any one of claims 1 to 6.
11. In claim 10, The above cathode active material is a cathode composition comprising 40 parts by weight or more based on 100 parts by weight of the above cathode composition.
12. A negative electrode current collector layer; and a negative electrode active material layer provided on one or both sides of the negative electrode current collector layer, comprising The negative electrode for a lithium secondary battery, wherein the negative electrode active material layer comprises a negative electrode composition according to claim 10 or a cured product thereof.
13. In claim 12, The thickness of the above-mentioned cathode current collector layer is 1 μm or more and 100 μm or less, and A negative electrode for a lithium secondary battery having a negative electrode active material layer thickness of 5 μm or more and 500 μm or less.
14. Anode; and Negative electrode for a lithium secondary battery according to claim 12; A lithium secondary battery including

Description

Negative electrode active material, manufacturing method of negative electrode active material, negative electrode composition, negative electrode for a lithium secondary battery comprising the same, and lithium secondary battery comprising the negative electrode {NEGATIVE ELECTRODE ACTIVE MATERIAL, MANUFACTURING METHOD OF NEGATIVE ELECTRODE ACTIVE MATERIAL, NEGATIVE ELECTRODE COMPOSITION, NEGATIVE ELECTRODE FOR LITHIUM SECONDARY BATTERY COMPRISING SAME, AND LITHIUM SECONDARY BATTERY COMPRISING NEGATIVE ELECTRODE} This application claims the benefit of the filing date of Korean Patent Application No. 10-2024-0154216 filed with the Korean Intellectual Property Office on November 4, 2024, the entire contents of which are incorporated herein. The present application relates to a negative electrode active material, a method for manufacturing a negative electrode active material, a negative electrode composition, a negative electrode for a lithium secondary battery comprising the same, and a lithium secondary battery comprising the negative electrode. Due to the rapid increase in the use of fossil fuels, there is a growing demand for alternative or clean energy. As part of this effort, the fields of power generation and energy storage utilizing electrochemical reactions are the most actively researched. Currently, a representative example of an electrochemical device utilizing such electrochemical energy is the secondary battery, and its scope of application is steadily expanding. With the increasing technological development and demand for mobile devices, the demand for secondary batteries as an energy source is rapidly rising. Among these secondary batteries, lithium-ion batteries, which possess high energy density and voltage, long cycle life, and low self-discharge rates, have been commercialized and are widely used. Furthermore, active research is being conducted on methods to manufacture high-density electrodes with higher energy density per unit volume for use in such high-capacity lithium-ion batteries. Generally, a secondary battery consists of a positive electrode, a negative electrode, an electrolyte, and a separator. The negative electrode includes a negative electrode active material that inserts and extracts lithium ions from the positive electrode, and a silicon-based active material with a large discharge capacity may be used as the negative electrode active material. In particular, due to the recent demand for high-density energy batteries, research is actively being conducted on methods to increase capacity by using silicon-based compounds such as Si/C or SiOx, which have a capacity more than 10 times greater than that of graphite-based materials, as negative electrode active materials. However, while silicon-based compounds, which are high-capacity materials, have the advantage of having a large capacity compared to graphite used conventionally, they have the problem of degrading battery characteristics by rapidly expanding in volume during the charging process, thereby disrupting the conductive path. Accordingly, various measures are being discussed to address the problems associated with using silicon-based compounds as negative electrode active materials, such as controlling the driving potential, coating additional thin films on the active material layer, controlling the particle size of silicon-based compounds to suppress volume expansion itself, or preventing the interruption of conductive paths. However, since these methods can actually degrade battery performance, their application is limited, and consequently, there are still limitations to the commercialization of negative electrode batteries with high silicon-based compound content. Recently, among silicon-based active materials, research on silicon-carbon composites has been conducted to secure characteristics such as energy density and rapid charging. However, silicon-carbon composites, which have high capacity and lifespan, are causing problems with slurry processability, and accordingly, improvements in processability are also necessary in the development of high-energy-density lithium secondary batteries. Therefore, research on the silicon carbon composite itself is necessary to improve the processability of the slurry even when using the silicon carbon composite as a negative electrode active material to enhance capacity, efficiency, and lifespan performance. FIG. 1 is a diagram showing a stacked structure of a negative electrode for a lithium secondary battery according to one embodiment of the present application. FIG. 2 is a diagram showing a stacked structure of a lithium secondary battery according to one embodiment of the present application. FIG. 3 is a graph showing the process of deriving the time constant for Example 2 according to the present application. Figure 4 is an SEM image of a negative electrode active material layer containing a silicon carbon composite according to Example 1. Figure 5 is a figure showing a