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US-12626925-B2 - Carbon material comprising particles with pore structures, method for preparing the same, and secondary battery and electrical device comprising the same

US12626925B2US 12626925 B2US12626925 B2US 12626925B2US-12626925-B2

Abstract

A carbon material includes an external region and an internal region disposed on the inside of the external region, the external region being a region formed by extending for a distance of 0.25 L from the surface of the particles of the carbon material towards the interior of the particles, L being a short-axis length of the particles of the carbon material; total pore area of the external region being denoted as S1 and total pore area of the internal region being denoted as S2, and S2>S1. The carbon material can make the secondary battery have high initial columbic efficiency, high energy density and good cycling performance. A method for preparing the carbon material, and a secondary battery and an electrical device comprising the carbon materials are also provided.

Inventors

  • Yonghong Chen
  • Rui Shen
  • Libing HE

Assignees

  • CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

Dates

Publication Date
20260512
Application Date
20241217

Claims (19)

  1. 1 . A carbon material, the carbon material comprising particles, each of the particles comprising an external region and an internal region inside the external region, the external region being a region formed by extending for a distance of 0.25 L from a surface of the particle of the carbon material towards interior of the particle, L being a short-axis length of the particle of the carbon material; the particle having more than one pore structure, a total pore area of the pore structures in the external region being denoted as S 1 and a total pore area of the pore structures in the internal region being denoted as S 2 , and S 2 >S 1 , 1.5≤S 2 /S 1 ≤500.
  2. 2 . The carbon material according to claim 1 , wherein 0.01 μm 2 ≤S 1 ≤10.0 μm 2 , optionally 0.1 μm 2 ≤S 1 ≤4.5 μm 2 ; and/or 1.8 μm 2 ≤S 2 ≤25.0 μm 2 , optionally 2.1 μm 2 ≤S 2 ≤20.0 μm 2 .
  3. 3 . The carbon material according to claim 1 , wherein L≥5 μm, optionally 6 μm≤L≤20 μm.
  4. 4 . The carbon material according to claim 1 , wherein each one of the pore structures in the external region of the particles has an area of less than 0.15 μm 2 , optionally less than or equal to 0.10 μm 2 .
  5. 5 . The carbon material according to claim 1 , wherein each one of the pore structures in the internal region of the particles has an area of greater than or equal to 0.15 μm 2 , optionally from 0.15 μm 2 to 2.0 μm 2 .
  6. 6 . The carbon material according to claim 1 , wherein the external region of the particles has an interlayer spacing denoted as d 1 , the internal region of the particles has an interlayer spacing denoted as d 2 , and the particles satisfy d 1 ≥d 2 ; optionally d 1 >d 2 ; optionally d 1 is from 0.33565 nm to 0.33615 nm; optionally d 2 is from 0.33557 nm to 0.33595 nm.
  7. 7 . The carbon material according to claim 1 , wherein the carbon material satisfies at least one of the following conditions: (1) the carbon material has a specific surface area of ≤2.1 m 2 /g, optionally from 0.7 m 2 /g to 1.8 m 2 /g; (2) the carbon material has a volume distribution particle size Dv50 of 8.0 μm-25.0 μm, optionally 9.0 μm-22.0 μm; (3) the carbon material has a volume distribution particle size Dv90 of 16.0 μm-35.0 μm, optionally 17.0 μm-34.0 μm; (4) the carbon material has a particle size distribution (Dv90−Dv10)/Dv50 of 0.5-1.5, optionally 0.7-1.3; (5) the carbon material has a morphology comprising one or more of blocky, spherical, and quasi-spherical shapes.
  8. 8 . The carbon material according to claim 1 , wherein the carbon material satisfies at least one of the following conditions: (1) the carbon material has a graphitization degree of from 91.5% to 98%, optionally from 92% to 98%; (2) the carbon material has a powder resistivity under a pressure of 8 MPa of 0.009 Ω·cm-0.052 Ω·cm, optionally 0.01 Ω·cm-0.04 Ω·cm; (3) the carbon material has a tap density of from 0.8 g/cm 3 to 1.50 g/cm 3 , optionally from 0.85 g/cm 3 to 1.45 g/cm 3 ; (4) the carbon material has a specific capacity of from 350 mAh/g to 372 mAh/g, optionally from 353 mAh/g to 371 mAh/g.
  9. 9 . A secondary battery, comprising a negative electrode plate comprising the carbon material according to claim 1 .
  10. 10 . An electrical device, comprising the secondary battery according to claim 9 .
  11. 11 . A carbon material, the carbon material comprising particles, each of the particles comprising an external region and an internal region inside the external region, the external region being a region formed by extending for a distance of 0.25 L from a surface of the particle of the carbon material towards interior of the particle, L being a short-axis length of the particle of the carbon material; the particle having more than one pore structure, a total pore area of the pore structures in the external region being denoted as S 1 and a total pore area of the pore structures in the internal region being denoted as S 2 , and S 2 >S 1 , 1.8 μm 2 ≤S 2 ≤25.0 μm 2 .
  12. 12 . The carbon material according to claim 11 , wherein 1.5≤S 2 /S 1 ≤500.
  13. 13 . The carbon material according to claim 11 , wherein, 0.01 μm 2 ≤S 1 ≤10.0 μm 2 .
  14. 14 . The carbon material according to claim 11 , wherein L≥5 μm, optionally 6 μm≤L≤20 μm.
  15. 15 . The carbon material according to claim 11 , wherein each one of the pore structures in the external region of the particles has an area of less than 0.15 μm 2 .
  16. 16 . The carbon material according to claim 11 , wherein each one of the pore structures in the internal region of the particles has an area of greater than or equal to 0.15 μm 2 .
  17. 17 . The carbon material according to claim 11 , wherein the external region of the particles has an interlayer spacing denoted as d 1 , the internal region of the particles has an interlayer spacing denoted as d 2 , and the particles satisfy d 1 ≥d 2 .
  18. 18 . The carbon material according to claim 11 , wherein the carbon material satisfies at least one of the following conditions: (1) the carbon material has a specific surface area of ≤2.1 m 2 /g, optionally from 0.7 m 2 /g to 1.8 m 2 /g; (2) the carbon material has a volume distribution particle size Dv50 of 8.0 μm-25.0 μm, optionally 9.0 μm-22.0 μm; (3) the carbon material has a volume distribution particle size Dv90 of 16.0 μm-35.0 μm, optionally 17.0 μm-34.0 μm; (4) the carbon material has a particle size distribution (Dv90−Dv10)/Dv50 of 0.5-1.5, optionally 0.7-1.3; (5) the carbon material has a morphology comprising one or more of blocky, spherical, and quasi-spherical shapes.
  19. 19 . The carbon material according to claim 11 , wherein the carbon material satisfies at least one of the following conditions: (1) the carbon material has a graphitization degree of from 91.5% to 98%, optionally from 92% to 98%; (2) the carbon material has a powder resistivity under a pressure of 8 MPa of 0.009 Ω·cm-0.052 Ω·cm, optionally 0.01 Ω·cm-0.04 Ω·cm; (3) the carbon material has a tap density of from 0.8 g/cm 3 to 1.50 g/cm 3 , optionally from 0.85 g/cm 3 to 1.45 g/cm 3 ; (4) the carbon material has a specific capacity of from 350 mAh/g to 372 mAh/g, optionally from 353 mAh/g to 371 mAh/g.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation of International Application No. PCT/CN2022/134483, filed on Nov. 25, 2022, which is hereby incorporated by reference in its entirety. TECHNICAL FIELD The present application belongs to the field of battery technology, and specifically relates to a carbon material and the method for preparing the same, and a secondary battery and an electrical device comprising the same. BACKGROUND In recent years, secondary batteries have been widely used in energy storage power systems such as hydro, thermal, wind and solar power plants, as well as electric tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace and many other fields. Negative electrode active materials are an important part of secondary batteries, because they affect the performances and cost of the secondary batteries. At present, the negative electrodes active materials mainly includes graphite, and natural graphite is currently receiving widespread attention due to its advantage of relatively low cost. However, natural graphite has defects such as more pores, more defects, and poor compatibility with electrolytic solution, which leads to poor cycling performance of secondary batteries. Therefore, how to improve the performance of natural graphite has become the focus of current research. SUMMARY The present application is intended to provide a carbon material, a method for preparing the same, and a secondary battery and an electrical device comprising the same. The carbon material provided in the present application enables the secondary battery to have high initial columbic efficiency, high energy density and good cycling performance. A first aspect of the present application provides a carbon material comprising an external region and an internal region disposed on the inside of the external region, the external region being a region formed by extending for a distance of 0.25 L from the surface of the particles of the carbon material towards the interior of the particles, L being a short-axis length of the particles of the carbon material; total pore area of the external region being denoted as S1 and total pore area of the internal region being denoted as S2, and S2>S1. When the carbon material provided in the present application satisfies S2>S1, the carbon material particles may have the following features: a high number of pores and/or a large pore size in the internal region and a low number of pores and/or a small pore size in the external region. The number of pores in the internal region of the carbon material particles is higher and/or the size of the pores is larger, whereby the pore structure can reserve the required expansion space for the volume change of the carbon material particles, thereby reducing the risk of fragmentation of the carbon material particles that generates new interfaces, thereby reducing the occurrence of side reactions, reducing the irreversible capacity loss of the secondary battery, and improving the cycling performance of the secondary battery; the number of pores in the external region of the carbon material particles is lower and/or the size of the pores is smaller, whereby the carbon material particles can be made to have a more stable structure, and infiltration of an electrolytic solution into the pore structure inside the carbon material particles can be avoided as much as possible, thereby being able to reduce the occurrence of side reactions, reduce the consumption of active ions for the formation of the SEI film inside the particles, and thus be able to enhance the initial coulombic efficiency of the carbon material and further improve the cycling performance of the secondary battery. Therefore, the carbon material provided in the present application can effectively reduce the irreversible capacity loss of the secondary battery, improve the capacity exertion characteristics of the secondary battery, and enable the secondary battery to have high initial coulombic efficiency, high energy density, and good cycling performance. In some embodiments of the present application, 1.5≤S2/S1≤500, optionally 2.5≤S2/S1≤120. When S2/S1 further satisfies the above condition, the secondary battery can better balance the high initial columbic efficiency, high energy density and good cycle performance. In some embodiments of the present application, 0.01 μm2≤S1≤10.0 μm2, optionally 0.1 μm2≤S1≤4.5 μm2. When the total pore area of the external region is within the above range, on the one hand, the carbon material particles can have a more stable structure, avoiding the infiltration of an electrolytic solution into the pore structure inside the carbon material particles as much as possible, thereby reducing the side reactions and reducing the consumption of active ions by SEI film formation inside the carbon material particles. On the other hand, the transport performance of active ions and electrons will not be