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CN-122025631-A - Hard carbon material, negative electrode plate, secondary battery and power utilization device

CN122025631ACN 122025631 ACN122025631 ACN 122025631ACN-122025631-A

Abstract

The application provides a hard carbon material, a negative electrode plate, a secondary battery and an electricity utilization device, and relates to the field of electrochemical energy storage; the hard carbon material comprises particles with a columnar shape, wherein the columnar body comprises at least one of a cylinder, a waist cylinder and a polygonal body, the polygonal body comprises at least one of a triangular prism, a quadrangular prism and a pentagonal prism, and when the hard carbon material is applied to a secondary battery, the hard carbon material has different small-angle X-ray diffraction characteristics under different charge states, wherein a scattering intensity convex peak is observed when a scattering vector is in a range of 0.1 nm ‑1 ～7 nm ‑1 under a 0% SOC, a scattering intensity convex peak is not observed when the scattering vector is in a range of 0.1 nm ‑1 ～7 nm ‑1 under a 100% SOC, and the compaction density of a negative electrode active material layer can be improved by optimizing the shape, so that the energy density, the circulation capacity retention rate and the rate capability of the secondary battery are improved.

Inventors

  • LU YUHAO
  • ZHENG ZIGUI
  • YI ZHENG
  • ZHAO MEIQI

Assignees

  • 宁德新能源科技有限公司

Dates

Publication Date
20260512
Application Date
20260416

Claims (10)

  1. 1. The hard carbon material is characterized by comprising particles with the shape of a columnar body, wherein the columnar body comprises at least one of a cylinder, a waist cylinder and a polygonal body, and the polygonal body comprises at least one of a triangular prism, a quadrangular prism and a pentagonal prism; When the hard carbon material is applied to a secondary battery, the hard carbon material has different small-angle X-ray diffraction characteristics under different charge states, wherein: at 0% SOC, a scattering intensity hump is observed with a scattering vector in the range of 0.1 nm -1 ～7 nm -1 ; At 100% SOC, no scatter intensity hump was observed with scatter vector in the range of 0.1 nm -1 ～7 nm -1 .
  2. 2. The hard carbon material according to claim 1, wherein the hard carbon material meets at least one of the following conditions: (1) The edges and corners of the polygon are in arc transition; (2) The edges of the polygon are in arc transition.
  3. 3. The hard carbon material according to claim 1 or 2, characterized in that the hard carbon material has a wide diffraction peak between 18 ° and 30 ° in an X-ray diffraction pattern, and the half-width of the wide diffraction peak is 4 ° to 12 °.
  4. 4. The hard carbon material according to claim 1 or 2, wherein the hard carbon material meets at least one of the following characteristics: (1) The hard carbon material has a pore volume of 0.1cm 3 /g to 0.9cm 3 /g; (2) The Dv50 of the hard carbon material is 3 μm to 10 μm; (3) The hard carbon material has a true density of 1.01g/cc to 1.67g/cc; (4) The specific surface area of the hard carbon material is 0.5m 2 /g to 50m 2 /g.
  5. 5. The hard carbon material according to claim 1 or 2, wherein the hard carbon material meets at least one of the following characteristics: (1) The hard carbon material has a pore volume of 0.31cm 3 /g to 0.45cm 3 /g; (2) The hard carbon material has a true density of 1.20g/cc to 1.34g/cc; (3) The specific surface area of the hard carbon material is 0.5m 2 /g to 5m 2 /g.
  6. 6. A negative electrode tab comprising a negative electrode current collector and a negative electrode active material layer on at least one surface of the negative electrode current collector, the negative electrode active material layer comprising a negative electrode active material; Characterized in that the anode active material includes the hard carbon material according to any one of claims 1 to 5; The hard carbon material is contained in an amount of 1.0 to 100% by mass based on the mass of the anode active material.
  7. 7. The negative electrode tab of claim 6, wherein the negative electrode active material layer meets at least one of the following characteristics: (1) The negative electrode active material layer has a compacted density of 0.9g/cm 3 to 1.72g/cm 3 ; (2) The porosity of the anode active material layer is 10% to 25%.
  8. 8. A secondary battery comprising the negative electrode tab of claim 6 or 7.
  9. 9. The secondary battery according to claim 8, further comprising a positive electrode tab including a positive electrode current collector and a positive electrode active material layer on at least one surface of the positive electrode current collector, the positive electrode active material layer including a positive electrode active material; The positive electrode active material includes a lithium transition metal oxide including at least one of nickel cobalt lithium manganate, nickel cobalt lithium aluminate, lithium iron phosphate, lithium-rich manganese-based material, lithium cobaltate, lithium manganate, lithium iron phosphate, and lithium titanate.
  10. 10. An electric device comprising the secondary battery according to claim 8 or 9.

Description

Hard carbon material, negative electrode plate, secondary battery and power utilization device Technical Field The application relates to the field of electrochemical energy storage, in particular to a hard carbon material, a negative electrode plate, a secondary battery and an electric device. Background As a clean energy source, the application of secondary batteries has been gradually expanded from portable electronic products to the field of large-sized electric devices such as electric automobiles. Based on this trend, there is a need to further increase the energy density of the secondary battery. Graphite materials are currently the most commercially available negative electrode materials with the most widespread use. However, the gram capacity of graphite materials currently widely used in the negative electrode of secondary batteries has approached its theoretical limit in practical applications, making it difficult to achieve further breakthrough in terms of energy density for secondary batteries with graphite as the negative electrode. Disclosure of Invention In view of the above-described drawbacks of the related art, an object of the present application is to provide a hard carbon material, a negative electrode tab, a secondary battery, and an electric device for overcoming the technical problem that the energy density of the secondary battery is difficult to be increased in the above-described related art, thereby obtaining a high energy density, and a secondary battery having excellent cycle capacity retention and rate capability. To achieve the above and other related objects, a first aspect of the present application provides a hard carbon material including particles having a morphology of a columnar body including at least one of a cylinder, a lumbar cylinder, and a polygonal body including at least one of a triangular prism-like shape, a quadrangular prism-like shape, and a pentagonal prism-like shape; When the hard carbon material is applied to a secondary battery, the hard carbon material has different small-angle X-ray diffraction characteristics under different charge states, wherein: at 0% SOC, a scattering intensity hump is observed with a scattering vector in the range of 0.1 nm -1～7 nm-1; At 100% SOC, no scatter intensity hump was observed with scatter vector in the range of 0.1 nm -1～7 nm-1. In certain embodiments of the first aspect of the present application, the hard carbon material is provided with particles having a columnar morphology, so that the morphology regularity of the hard carbon material can be improved, the surface contact among the particles is mainly used, the true density is effectively improved, the compacted density of the anode active material layer is further improved, the porosity of the anode active material layer is reduced, the adsorption capacity of electrolyte is reduced, the hard carbon material presents a disordered carbon structure, the hard carbon material further has a higher gram capacity, the small-angle X-ray diffraction characteristic (0% SOC has scattering peaks and 100% SOC is non-peak) proves that the pores are filled with lithium in the lithium storage process, the lithium storage capacity is improved, and the energy density, the circulation capacity retention rate and the multiplying power performance of the secondary battery are improved when the hard carbon material is applied to the secondary battery. Based on the first aspect, in some possible embodiments, the corners of the polygon adopt arc transitions. Based on the first aspect, in some possible embodiments, the edges of the polygon adopt a circular arc transition. Based on the first aspect, in some possible embodiments, the hard carbon material meets at least one of the following conditions: (1) The edges and corners of the polygon are in arc transition; (2) The edges of the polygon are in arc transition. Based on the first aspect, in some possible embodiments, in the X-ray diffraction pattern of the hard carbon material, there is a broad diffraction peak between 18 ° and 30 °, and the half-width of the broad diffraction peak is between 4 ° and 12 °. Based on the first aspect, in some possible embodiments, the hard carbon material has a pore volume of 0.1cm 3/g to 0.9cm 3/g. Based on the first aspect, in some possible embodiments, the hard carbon material has a pore volume of 0.31cm 3/g to 0.45cm 3/g. Based on the first aspect, in some possible embodiments, the Dv50 of the hard carbon material is 3 μm to 10 μm. Based on the first aspect, in some possible embodiments, the Dv50 of the hard carbon material is 5 μm. Based on the first aspect, in some possible embodiments, the hard carbon material has a true density of 1.01g/cc to 1.67g/cc. Based on the first aspect, in some possible embodiments, the hard carbon material has a true density of 1.20g/cc to 1.34g/cc. Based on the first aspect, in some possible embodiments, the hard carbon material has a specific surface area of 0.5m 2/g