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JP-7855681-B2 - Negative electrode material, battery

JP7855681B2JP 7855681 B2JP7855681 B2JP 7855681B2JP-7855681-B2

Inventors

  • 俎 ▲夢▼▲楊▼
  • ▲張▼ ▲夢▼
  • 李 子坤
  • 黄 健
  • 任 建国

Assignees

  • 貝特瑞新材料集団股▲フン▼有限公司

Dates

Publication Date
20260508
Application Date
20230628

Claims (10)

  1. A negative electrode material containing graphite, The graphite has pores inside and/or on its surface, and the negative electrode material has an oil absorption of 0 mL/100 g, a pore volume of V cm³ /kg, a specific surface area of S m² /g, and a powder porosity of Φ%, such that 50 ≤ 0 × V × S ≤ 391 and 40 ≤ Φ ≤ 58. The aforementioned pore volume was measured using an ASAP 2460 instrument manufactured by Micromerities, Inc., USA, and calculated within the pore diameter range of 17 Å to 3000 Å using the BJH Desorption Cumulative Volume of Pores model . The aforementioned powder porosity was measured using the AutoPore V series high-performance fully automatic mercury intrusion porosimeter manufactured by Micromeritics. The anode material is characterized by satisfying 30.3 ≤ O ≤ 62.1, 1.897 ≤ V ≤ 5.012, and 0.879 ≤ S ≤ 1.781 .
  2. The negative electrode material according to claim 1, characterized in that when the oil absorption amount is 0 mL/100 g, 31.2 ≤ 0 ≤ 62.
  3. The negative electrode material according to claim 1, characterized in that when the pore volume is V cm³ /kg, 1.945 ≤ V ≤ 5.012.
  4. The negative electrode material according to claim 1, characterized in that when the specific surface area is Sm² /g, 0.894 ≤ S ≤ 1.781.
  5. The negative electrode material according to claim 1, characterized in that the particle size satisfies the relationship 12 μm ≤ D 50 ≤ 20 μm.
  6. The negative electrode material according to any one of claims 1 to 5, further comprising amorphous carbon, wherein the amorphous carbon is present on the surface of the graphite and/or dispersed between graphite particles.
  7. The negative electrode material according to claim 6, characterized in that it satisfies at least one of the following features (1) to (3). (1) The mass percentage of amorphous carbon in the negative electrode material is 0.1 wt% to 5 wt%; (2) The negative electrode material includes artificial graphite primary particles and/or artificial graphite secondary particles; (3) The pores include at least one of micropores and mesopores.
  8. The negative electrode material according to any one of claims 1 to 5, characterized in that, when the interplanar spacing of the (002) plane is set to d 002 by X-ray diffraction measurement, 3.358 Å ≤ d 002 ≤ 3.365 Å, and the deposition thickness (Lc) of the crystal layer plane determined by X-ray diffraction measurement is 400 Å to 450 Å.
  9. The negative electrode material according to any one of claims 1 to 5, characterized in that, by X-ray diffraction measurement under a pressure of 9T, the ratio (I 004 / I 110 ) of the integrated intensity of the peak belonging to the ( 004 ) plane of the negative electrode material to the integrated intensity of the peak belonging to the ( 110) plane of the negative electrode material is 1.0 ≤ I 004 / I 110 ≤ 5.0.
  10. Claim 1～ 5 A battery characterized by containing the negative electrode material described in any one of the items.

Description

This application relates to the technical field of negative electrode materials, and more specifically, to negative electrode materials and batteries. Graphite has several advantages, including high electrical conductivity, a large lithium-ion diffusion coefficient, minimal volume change before and after lithium absorption in its layered structure, high lithium absorption capacity, and a low lithium absorption potential. For these reasons, it is currently the dominant negative electrode material in commercially available lithium-ion batteries. Graphite materials also have many drawbacks as anode materials for lithium-ion batteries. The electrolyte absorption performance of the material and electrode pieces in a lithium-ion battery significantly impacts the battery's final performance. Poor anode electrolyte absorption limits the reactable area of the graphite anode material, resulting in insufficient electrochemically active sites, limiting the battery's rate performance, forming lithium deposits, and further degrading the battery's rate performance and capacity, potentially having a serious impact on battery safety and cycle life. Therefore, good electrolyte absorption performance and an effective reactable area of the material both have a positive effect on the rate performance and capacity of lithium-ion batteries. Therefore, at the current stage where graphite material development has already matured, it is difficult to further optimize rate performance by simply improving parameters. Currently, in order to maximize the rate performance of graphite, it is necessary to diligently study the synergistic effects between multiple factors. This is a scanning electron microscope image of the graphite anode material provided in Example 11 of this application.This is a scanning electron microscope image of the graphite anode material provided in Example 12 of this application. To better explain this application and facilitate understanding of its proposed technology, the application will be described in further detail below. Note that the following embodiments are merely simplified examples of this application and do not indicate or limit the scope of protection. The scope of protection of this application is as defined in the claims. The negative electrode material contains graphite and has pores inside and/or on the surface of the graphite. When the oil absorption is 0 mL/100 g, the pore volume is V cm³ /kg, the specific surface area is S m² /g, and the powder porosity is Φ%, the negative electrode material satisfies 50 ≤ 0 × V × S ≤ 391 and 40 ≤ Φ ≤ 58. The pore volume was measured using an ASAP 2460 instrument manufactured by Micromerities, Inc., USA, and calculated within the pore diameter range of 17 Å to 3000 Å using the BJH Desorption Cumulative Volume of Pores model. The negative electrode material has pores inside and/or on the surface of the graphite, and when the oil absorption is 0 mL/100 g, the pore volume is V cm³ /kg, the specific surface area is S m² /g, and the powder porosity is Φ%, then 50 ≤ 0 × V × S ≤ 391 and 40 ≤ Φ ≤ 58. Generally, particles with large pore volume can increase the diffusion channels for Li + , and a large specific surface area can ensure a sufficient electrochemical reaction interface, promoting the diffusion of lithium ions at the solid-liquid interface and within the solid phase, reducing concentration polarization, and improving the capacity and rate performance of the anode material. However, lithium ion release and storage require not only diffusion channels and reaction interfaces, but also an electrolyte as a medium. Lithium ions achieve the purpose of lithium storage through lithium ion release and storage by diffusion of lithium ions into the electrolyte. The lithium storage mode involves lithium ions diffusing between the intermediate layers of graphite to achieve the purpose of lithium storage, and also involves lithium storage at the edges and on the surface. Therefore, even if appropriate pore volume and specific surface area are met, there is still room for improvement in the rate performance of the anode material. Here, intercalated lithium storage of graphite is an intercalation process from higher to lower order in which lithium ions are inserted between the graphite layers. Carbon atoms exposed at the edges of the graphite sheet layer are in an amorphous state, have high energy, and are active sites for lithium ions, enabling lithium storage at the edges. The bonding between carbon atoms on the graphite surface and lithium ions is similar to lithium storage at the edges, i.e., it enables lithium storage on the surface. Some pores cannot penetrate the electrolyte and exert their effect due to the influence of surface morphology, pore structure, or other factors, but due to capillary action, the electrolyte first penetrates partly into the voids between graphite particles and partly into the surface or internal voids of the graphite particles. However, simp