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CN-122010090-A - Composite hard carbon negative electrode material, preparation method thereof and battery

CN122010090ACN 122010090 ACN122010090 ACN 122010090ACN-122010090-A

Abstract

The invention provides a composite hard carbon anode material, a preparation method thereof and a battery, wherein the preparation method comprises the steps of mixing asphalt with ion exchange resin to obtain a first precursor; the method comprises the steps of carbonizing a first precursor to obtain a second precursor, doping nitrogen into the second precursor to obtain a third precursor, carrying out plasma treatment on the third precursor to obtain the composite hard carbon negative electrode material, and the battery comprises the composite hard carbon negative electrode material obtained by the method. The invention solves the contradiction between the cost of raw materials and the consistency of performance in the prior art, solves the balance problem of electronic conductivity and ion transmission, and also solves the problems that dead pores or closed pores on the surface of the traditional hard carbon material cannot be effectively infiltrated by electrolyte and the contact resistance is large due to particle aggregation.

Inventors

  • REN ZHANXIN
  • WEI ZHIWEI

Assignees

  • 杰瑞新能源科技有限公司

Dates

Publication Date
20260512
Application Date
20260206

Claims (10)

  1. 1. The preparation method of the composite hard carbon anode material is characterized by comprising the following steps of: mixing asphalt with ion exchange resin to obtain a first precursor; Carbonizing the first precursor to obtain a second precursor; carrying out nitrogen doping treatment on the second precursor to obtain a third precursor; and carrying out plasma treatment on the third precursor to obtain the composite hard carbon anode material.
  2. 2. The method of manufacturing of claim 1, characterized by at least one of the following features: the preparation method further comprises pretreatment, wherein the pretreatment is respectively carried out on raw material asphalt and raw material ion exchange resin before asphalt is mixed with the ion exchange resin; The carbonization treatment is gradient carbonization treatment, and the gradient carbonization treatment comprises three stages of low-temperature devolatilization, medium-temperature crosslinking and high-temperature carbonization; The nitrogen doping treatment is ammoniation nitrogen doping treatment, and the ammoniation nitrogen doping treatment comprises a first stage of introducing inert gas and a second stage of introducing ammonia gas; the plasma treatment is performed under an inert atmosphere.
  3. 3. The preparation method according to claim 2, wherein in the pretreatment, coarse crushing, fine crushing, drying and impurity detection are sequentially carried out on raw asphalt, wherein the D50 of the asphalt after fine crushing is 3-10 μm or 5-7 μm, vacuum drying is carried out under the pressure of-0.080 to-0.098 MPa or-0.095 MPa, the drying temperature is 100-150 ℃ or 120 ℃, the drying time is 2-6 h or 4h, and the ash content after detection is less than or equal to 2wt%; In the pretreatment, the raw material ion exchange resin is subjected to primary cleaning, heavy metal removal, neutral washing, low-temperature drying and fine crushing in sequence, wherein water, ethanol or acetone is used as a cleaning liquid in the primary cleaning, the liquid-solid ratio is (1-10): 1 or (3-8): 1, the ultrasonic frequency is 30-80 kHz, hydrochloric acid with the concentration of 0.1-1 mol/L is used for treatment at 30-70 ℃, the low-temperature drying temperature is 50-100 ℃, and the D50 of the crushed resin is 3-10 mu m or 5-7 mu m.
  4. 4. The method of preparing of claim 2, wherein the preparation of the first precursor has at least one of the following characteristics: the mass ratio of the asphalt to the ion exchange resin is (4-8): (6~2); mixing by adopting a ball mill, the ball milling rotating speed is 300-800 rpm, ball milling time is 1-10 h; The softening point of the asphalt is 160-210 ℃, the carbon content is greater than or equal to 95wt%, and the volatile content is 25-30 wt%; the ion exchange resin is waste styrene ion exchange resin, the exchange capacity is greater than or equal to 4.5mmol/g, the water content is less than or equal to 10wt%, and the impurity content is less than or equal to 50ppm.
  5. 5. The method of claim 2, wherein the gradient carbonization process is characterized by at least one of: the low-temperature devolatilization temperature is 200-400 ℃, the duration is 1-3 h, and the temperature rising rate is 4-6 ℃ per minute; The temperature of the medium-temperature crosslinking is 500-700 ℃, the time length is 1-3 h, and the temperature rising rate is 2-4 ℃ per minute; the high-temperature carbonization temperature is 900-1100 ℃, the time is 2-5 h, the heating rate is 1-3 ℃ per minute, and the gradient carbonization treatment is performed under the atmosphere of argon or nitrogen.
  6. 6. The method of claim 2, wherein the ammoniated nitrogen dosing process has at least one of the following characteristics: The temperature of the ammoniation nitrogen-doped treatment is 700-950 ℃, the time length is 1-5 h, and the temperature rising rate is 2-10 ℃ per minute; argon or nitrogen is introduced into the first stage; And introducing ammonia gas in the second stage, wherein the gas flow rate of the ammonia gas is 30-80 mL/min or 40-80 mL/min.
  7. 7. The method of claim 2, wherein the plasma treatment comprises at least one of the following characteristics: the gas flow is 10-80 mL/min or 20-60 mL/min; the gas pressure is 0.1-0.5 MPa or 0.15-0.4 MPa; the duration of the plasma treatment is 5-20 min or 8-12 min; the power of the plasma treatment is 100-200W or 120-180W.
  8. 8. A composite hard carbon anode material, characterized in that the composite hard carbon anode material is produced by the production method of any one of claims 1 to 7.
  9. 9. The composite hard carbon negative electrode material of claim 8, having at least one of the following characteristics: The specific surface area of the composite hard carbon anode material is 1-20 m < 2 >/g or 2-10 m < 2 >/g; the average pore diameter of the composite hard carbon anode material is 0.3-1.5 nm or 0.4-1 nm; the median particle diameter D50 of the composite hard carbon anode material is 4-10 mu m or 5-7 mu m; the true density of the composite hard carbon anode material is 1.4-1.6 g/cm <3>, and the tap density is 0.5-0.9 g/cm <3> or 0.6-0.8 g/cm <3 >; the closed pore volume of the composite hard carbon anode material is 0.20-0.30 cm < 3 >/g; the nitrogen content of the composite hard carbon anode material is 1.5-2.5wt%; The powder conductivity of the composite hard carbon anode material is 100-150S/m; the ash content of the composite hard carbon negative electrode material is less than or equal to 0.8wt%.
  10. 10. A battery, characterized in that the battery comprises the composite hard carbon anode material obtained by the preparation method according to any one of claims 1 to 7, or comprises the composite hard carbon anode material according to claim 8 or 9; the battery is a sodium ion battery, the sodium storage capacity of the battery at the 1C multiplying power is 270-290 mAh/g, the 500-cycle capacity retention rate is more than or equal to 85%, and the capacity retention rate at the 5C multiplying power is more than or equal to 70%.

Description

Composite hard carbon negative electrode material, preparation method thereof and battery Technical Field The invention relates to the technical field of hard carbon negative electrode materials, in particular to a composite hard carbon negative electrode material, a preparation method thereof and a battery. Background The preparation and application of the existing hard carbon anode material still face multiple technical bottlenecks. First, there is a contradiction between "stability and cost" in raw material selection. The current mainstream biomass raw materials (such as coconut shells and straws) have complex components and large production area difference, so that consistency among product batches is difficult to ensure, and the synthetic polymer materials such as phenolic resin and the like have high purity and controllable structure, but high cost limits large-scale industrialized application. Inexpensive coal-or petroleum-based pitch, although high in carbon content and low in cost, tends to form a dense soft carbon or graphitized structure after direct carbonization, and lacks sufficient pore channels for sodium ion diffusion, resulting in poor sodium storage capacity and rate capability. Secondly, in terms of preparation process and microstructure regulation, the traditional single high-temperature carbonization process is difficult to simultaneously achieve high capacity and high first efficiency. On the one hand, in order to improve the graphitization degree and conductivity of the material, a higher carbonization temperature is usually required, but the micropores are closed, so that the sodium storage capacity is reduced, on the other hand, the hard carbon material carbonized at a low temperature has a large number of defects and high capacity, but has poor conductivity, and a large number of irreversible active sites exist on the surface, so that the first coulombic efficiency (ICE) is low. In order to improve conductivity, the prior art usually adopts heteroatom doping (such as nitrogen and phosphorus doping), but the problem of electron transmission can only be solved, and the problems of high ion transmission resistance and high contact resistance caused by surface micropore blocking or particle agglomeration can not be solved effectively. In addition, in order to improve the interface stability, part of the prior art adopts a surface coating means, but the traditional liquid phase or solid phase coating process is easy to cause uneven coating layers, and the pore structure of the material surface layer is difficult to accurately regulate and control. Particularly, for asphalt-based or resin-based hard carbon materials, the electrolyte is difficult to fully infiltrate due to the lack of enough active functional groups or closed dead holes on the surface of the asphalt-based or resin-based hard carbon materials, so that the storage space inside the materials cannot be effectively utilized, and the energy density and the rapid charge and discharge capacity of the battery are severely restricted. Disclosure of Invention The invention provides a composite hard carbon negative electrode material, a preparation method thereof and a battery, which are used for solving the contradiction between the cost of raw materials and the consistency of performance in the prior art, solving the balance problem of electronic conductivity and ion transmission, and solving the problems that dead holes or closed holes on the surface of the traditional hard carbon material cannot be effectively infiltrated by electrolyte and contact resistance is large due to particle aggregation. In order to achieve the above purpose, the present invention provides the following technical solutions: A preparation method of the composite hard carbon anode material comprises the steps of mixing asphalt with ion exchange resin to obtain a first precursor, carbonizing the first precursor to obtain a second precursor, doping nitrogen into the second precursor to obtain a third precursor, and carrying out plasma treatment on the third precursor to obtain the composite hard carbon anode material. In order to achieve the above purpose, the present invention also provides the following technical solutions: the composite hard carbon negative electrode material is prepared by the preparation method. In order to achieve the above purpose, the present invention also provides the following technical solutions: The battery comprises the composite hard carbon negative electrode material obtained by the preparation method or the composite hard carbon negative electrode material, wherein the battery is a sodium ion battery, the sodium storage capacity of the battery at the 1C multiplying power is 270-290 mAh/g, the 500-cycle capacity retention rate is greater than or equal to 85%, and the capacity retention rate at the 5C multiplying power is greater than or equal to 70%. Compared with the prior art, the invention has the following beneficial eff