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KR-20260062459-A - ANODE FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY INCLUDING THE SAME

KR20260062459AKR 20260062459 AKR20260062459 AKR 20260062459AKR-20260062459-A

Abstract

A negative electrode for a lithium secondary battery according to one embodiment of the present disclosure comprises a negative electrode current collector and a negative electrode composite layer on at least one surface of the negative electrode current collector, wherein the negative electrode composite layer comprises a carbon-based active material, and the negative electrode for a lithium secondary battery has a crystal orientation index increase rate (R OI ) according to Formula 1 below of 120% to 400%. [Equation 1] R OI = 100 In the above Equation 1, R OI is the growth rate (%) of the crystal orientation index (OI), OI 1 is the ratio (I 004 / I 110 ) of the peak intensity of the ( 004 ) plane to the peak intensity of the ( 110 ) plane according to X-ray diffraction (XRD) analysis of the carbon-based active material, and OI 2 is the ratio (I 004 / I 110 ) of the peak intensity of the (004) plane to the peak intensity of the ( 110 ) plane according to X-ray diffraction (XRD) analysis of the cathode composite layer according to X-ray diffraction ( XRD ) analysis. According to one embodiment of the present disclosure, a negative electrode for a lithium secondary battery with excellent energy density can be provided.

Inventors

  • 이하진
  • 전찬영
  • 김경훈

Assignees

  • 에스케이온 주식회사

Dates

Publication Date
20260507
Application Date
20241029

Claims (11)

  1. As a negative electrode for a lithium secondary battery, The negative electrode for the lithium secondary battery comprises a negative electrode current collector and a negative electrode composite layer on at least one surface of the negative electrode current collector, and The above cathode composite layer includes a carbon-based active material, and The negative electrode for the lithium secondary battery above has a crystal orientation index increase rate (R OI ) according to Formula 1 below of 120% to 400%, Negative electrode for lithium secondary battery; [Equation 1] R OI = 100 In the above Equation 1, R OI is the growth rate (%) of the crystal orientation index (OI), OI 1 is the ratio (I 004 / I 110 ) of the peak intensity of the ( 004 ) plane to the peak intensity of the ( 110 ) plane according to X-ray diffraction (XRD) analysis of the carbon-based active material, and OI 2 is the ratio (I 004 / I 110 ) of the peak intensity of the (004) plane to the peak intensity of the ( 110 ) plane according to X-ray diffraction (XRD) analysis of the cathode composite layer according to X-ray diffraction ( XRD ) analysis.
  2. In paragraph 1, The above negative electrode for a lithium secondary battery has a crystal orientation index increase rate (R OI ) of 190% to 270%, Negative electrode for lithium secondary battery.
  3. In paragraph 1, The negative electrode for the lithium secondary battery above is OI 2 according to Equation 1 above. Values of 7 to 15, Negative electrode for lithium secondary battery.
  4. In paragraph 1, The above carbon-based active material includes artificial graphite, Negative electrode for lithium secondary battery.
  5. In paragraph 4, The above artificial graphite has a single-particle form, Negative electrode for lithium secondary battery.
  6. In paragraph 4, The above artificial graphite includes a carbon coating layer on its surface, Negative electrode for lithium secondary battery.
  7. In paragraph 1, The above carbon-based active material includes artificial graphite and natural graphite, Negative electrode for lithium secondary battery.
  8. In Paragraph 7, Among the above carbon-based active materials, the weight of artificial graphite is greater than or equal to the weight of natural graphite, Negative electrode for lithium secondary battery.
  9. In Paragraph 7, The above natural graphite includes a carbon coating layer on its surface, Negative electrode for lithium secondary battery.
  10. In paragraph 1, The electrode density of the above cathode composite layer is 1.4 g/cc to 1.7 g/cc, Negative electrode for lithium secondary battery.
  11. A negative electrode for a lithium secondary battery according to any one of claims 1 to 10, Lithium secondary battery.

Description

Anode for lithium secondary battery and lithium secondary battery including the same The present disclosure relates to a negative electrode for a lithium secondary battery and a lithium secondary battery including the same. Recently, extensive research has been conducted on electric vehicles (EVs) to replace fossil fuel-powered vehicles, such as gasoline and diesel cars, which are major causes of air pollution. Lithium-ion batteries, which offer high discharge voltage and output stability, are primarily used as the power source for these EVs. Consequently, there is an increasing need for high-performance anodes for lithium-ion batteries. FIG. 1 is a conceptual diagram showing a Basal Plane corresponding to a basal plane and an Edge Plane formed by the convergence of the edges of each of the basal planes in a carbon-based active material having a parallel stacked structure. In this specification, the ‘orientation’ of the composite layer and the active material refers to a characteristic represented by the ‘Orientation Index (OI)’ value, which is determined by the peak intensity ratio between the peak intensity of the (004) plane (I 004 ) and the peak intensity of the (110) plane (I 110 ) according to XRD measurement. For example, the lower the OI value of the composite layer and the active material, the lower the orientation, and the more the OI value is relatively small, the lower the orientation, and the higher the orientation, the higher the orientation. In order to provide a high-performance lithium secondary battery, a negative electrode for a lithium secondary battery according to one embodiment may include artificial graphite made of coke as a negative electrode active material. The artificial graphite has many pathways through which lithium ions can pass, thereby improving the high-output performance and rapid charging performance of the lithium secondary battery. Specifically, the orientation of the carbon-based active material, such as the artificial graphite, is described in detail below with reference to FIG. 1. FIG. 1 is a conceptual diagram showing a Basal Plane corresponding to the base plane and an Edge Plane formed by the convergence of the edges of each of the basal planes in a carbon-based active material having a parallel stacked structure. The carbon-based active material (1), such as artificial graphite, generally comprises carbon layers in which hexagonal rings composed of six carbon atoms are connected in a planar manner, and the carbon layers are stacked parallel to each other (see FIG. 1). In the carbon-based active material (1), the basin plane (2) corresponds to the basal plane in the carbon layers having a structure stacked in parallel, and the edge plane (3) refers to the plane formed by the edges of each of the basal planes coming together. During the charging and discharging process of a lithium secondary battery, the intercalation and deintercalation phenomena in which lithium ions are stored and released in the carbon-based active material (1) are mainly carried out through the edge planes (3). Therefore, as the number of these edge planes (3) increases, the intercalation and deintercalation of lithium ions during the charging process become easier, and the rapid charging characteristics can also be more excellent. In this regard, the crystal orientation index (OI) value determined by X-ray diffraction (XRD) analysis of the carbon-based active material (1) represents the peak intensity of the (110) plane relative to the (004) plane, and the smaller the OI value of the carbon-based active material (1), the more the structure may have a relatively larger number of edge planes (3) relative to the base planes (2). This is determined to be due to the fact that as the crystal orientation index (OI) value decreases, the disorder of the crystal arrangement increases, and the number of edge planes (3) through which lithium ions can enter and exit increases. Therefore, the lower the orientation of the carbon-based active material included in the negative electrode, the easier it is for lithium ions to enter and exit through many edge planes (3), and thus the output performance and rapid charging performance may be excellent. However, as the 'orientation' decreases, the hardness of carbon-based active materials increases, making it difficult to roll low-orientation carbon-based active materials to high density. Consequently, when the anode contains low-orientation carbon-based active materials, it is difficult to increase the rolling density of the anode, which may make it difficult to secure the anode's energy density. Furthermore, the particles of low-orientation carbon-based active materials may be damaged during the rolling process, which can lead to additional side reactions or degrade the battery's lifespan performance. In this regard, the artificial graphite is a low-orientation active material with low orientation, and thus, it may not be easy to roll a cathode containing the a