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CN-122010086-A - Low-temperature hard carbon, preparation method thereof and sodium ion battery

CN122010086ACN 122010086 ACN122010086 ACN 122010086ACN-122010086-A

Abstract

The invention relates to the field of sodium ion batteries, in particular to low-temperature hard carbon, a preparation method thereof and a sodium ion battery; the invention adopts the phenolic resin precursor and the honeycomb briquette precursor to prepare the hard carbon by compounding, and the skeleton structure of the hard carbon material is stabilized and the porous structure of the hard carbon is controlled by the self structures of the two materials. The method of dispersing metal ions in a carbon material structure and then removing the metal ions through acid washing to form a pore structure is avoided. The method can achieve the effects of controlling the skeleton structure stability and the porous structure of the hard carbon material without adopting metal ions, can effectively reduce the use of additives, simplify the manufacturing process of the hard carbon and reduce the cost. The sodium ion battery has good circulation stability in a low-temperature scene and high Wen Changjing, compared with other batteries, the problem that the high-temperature performance is sacrificed when the low-temperature performance is improved, and the market competitiveness of the sodium ion battery can be effectively improved.

Inventors

  • LI ENYU
  • CAI XIANYU
  • LIU XINGSHUANG
  • WANG JUNHONG
  • QIU XINGQI
  • JIANG JINLIN

Assignees

  • 双登集团股份有限公司
  • 江苏双登富朗特新能源有限公司

Dates

Publication Date
20260512
Application Date
20260123

Claims (10)

  1. 1. The preparation method of the low-temperature hard carbon is characterized by comprising the following steps of: s1, mixing and dispersing pretreated honeycomb briquette and thermosetting phenolic resin powder into ethanol, uniformly stirring, adding a block copolymer and a nitrogen source, stirring again, and sequentially carrying out suction filtration treatment, washing treatment and drying treatment to obtain a composite material; S2, carrying out crosslinking treatment, carbonization treatment, grinding treatment and cleaning treatment on the composite material in sequence to obtain the low-temperature hard carbon.
  2. 2. The preparation method of the honeycomb briquette according to claim 1, wherein in the step S1, the pretreatment of the honeycomb briquette comprises the steps of grinding the honeycomb briquette into powder with the particle size of less than 200 mu m, adding the powder into a compound acid for pickling for 4-6 hours, adding sodium hydroxide for adjusting the pH value to be neutral, carrying out suction filtration, washing a product by deionized water, carrying out suction filtration again, washing the product by deionized water for three times, carrying out suction filtration again to obtain a filtrate, and baking the filtrate in an oven for 10-12 hours to obtain the pretreated honeycomb briquette.
  3. 3. The method according to claim 2, wherein the complex acid comprises two of sulfuric acid, hydrochloric acid, hydrofluoric acid and nitric acid in a volume ratio of (2:8) - (8:2), and the injection rate of the honeycomb briquette into the complex acid is 30-100mg/min.
  4. 4. The method according to claim 1, wherein in step S1, the thermosetting phenol resin powder has a particle size of less than 200 μm.
  5. 5. The method according to claim 1, wherein in step S1, the mass ratio of the honeycomb briquette to the thermosetting phenol resin powder is (2:8) - (5:5).
  6. 6. The method according to claim 1, wherein in the step S1, the block copolymer comprises at least one of ：PEO 100 -PPO 65 -PEO 100 、PEO 20 -PPO 70 -PEO 20 、PEO 141 -PPO 44 -PEO 141 、PMMA-PEO, and the nitrogen source comprises at least one of polyaniline, ammonium nitrate, urea, and an amino acid.
  7. 7. The method according to claim 1, wherein the washing treatment in step S1 comprises alternately washing with deionized water and ethanol.
  8. 8. The method according to claim 1, wherein in the step S2, the crosslinking treatment is performed at a temperature of 300-400 ℃ for 3-5 hours, and the carbonization treatment comprises heating to 1000-1500 ℃ at a rate of 5 ℃/min, carbonizing for 2-4 hours, and naturally cooling to room temperature under an argon atmosphere.
  9. 9. A low temperature hard carbon produced by the production method according to any one of claims 1 to 8.
  10. 10. A sodium ion battery prepared from the low temperature hard carbon prepared by the method of any one of claims 1-8, comprising the steps of: A1, mixing low-temperature hard carbon, a conductive agent, a binder and a solvent according to a mass ratio to prepare negative electrode slurry, and preparing a negative electrode plate after coating, rolling and blanking; A2, mixing the layered oxide, the conductive agent, the binder and the solvent according to the mass ratio to prepare anode slurry, and preparing an anode plate after coating, rolling and blanking; A3, assembling the positive plate, the diaphragm and the negative plate, and preparing the sodium ion battery after liquid injection, formation, capacity division and aging.

Description

Low-temperature hard carbon, preparation method thereof and sodium ion battery Technical Field The invention relates to the field of sodium ion batteries, in particular to low-temperature hard carbon, a preparation method thereof and a sodium ion battery. Background In winter, the low-temperature area is wide, the standby battery in the low-temperature area communication base station has the dilemma of difficult charging, and the existing mode is to ensure that the battery can be charged by installing an air conditioner in a machine room, adding heating equipment, burying the ground and the like. However, in the method, the heat preservation effect is still poor, the service life of the battery can be greatly reduced, and the operation of the base station in the cold region is influenced, so that the development of the battery with the low-temperature charging performance has great significance. Compared with a lithium ion battery, the sodium ion battery has good low-temperature performance and can be charged below 0 ℃, so that the sodium ion battery has good competitiveness in the low-temperature field. The hard carbon material is a common material for preparing a negative electrode of a sodium ion battery, and has the problem of low initial coulombic efficiency due to excessive defects and excessive pores on the surface of the hard carbon, which can cause more irreversible loss of sodium ions in the first charge and discharge process of the battery to reduce the capacity and energy density of the battery, and meanwhile, the capacity of the hard carbon material consists of a platform region and a slope region, and if the capacity ratio of the two parts is unreasonable, the dynamic performance of the battery is reduced. At present, a learner modifies hard carbon by adding metal salt, however, if the acid washing process is insufficient or the acid washing process is not matched with the metal salt, the residual metal ions are caused, the formation of a pore structure of a hard carbon material is influenced, and the electrical performance of a battery is finally influenced. Disclosure of Invention The invention aims at overcoming the defects in the prior art and provides low-temperature hard carbon, a preparation method thereof and a sodium ion battery. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the first aspect of the invention provides a method for preparing low-temperature hard carbon, comprising the following steps: s1, mixing and dispersing pretreated honeycomb briquette and thermosetting phenolic resin powder into ethanol, uniformly stirring, adding a block copolymer and a nitrogen source, stirring again, and sequentially carrying out suction filtration treatment, washing treatment and drying treatment to obtain a composite material; S2, carrying out crosslinking treatment, carbonization treatment, grinding treatment and cleaning treatment on the composite material in sequence to obtain the low-temperature hard carbon. Preferably, in the step S1, the pretreatment of the honeycomb briquette comprises the steps of grinding the honeycomb briquette into powder with the particle size smaller than 200 mu m, adding the powder into a compound acid for pickling for 4-6 hours, adding sodium hydroxide for regulating the pH value to be neutral, carrying out suction filtration, cleaning a product by deionized water, carrying out suction filtration again, cleaning the product by deionized water for three times again, carrying out suction filtration to obtain a filtrate, and baking the filtrate in an oven for 10-12 hours to obtain the pretreated honeycomb briquette. More preferably, the compound acid comprises two of sulfuric acid, hydrochloric acid, hydrofluoric acid and nitric acid, the volume ratio of the two acids is (2:8) - (8:2), and the injection rate of the honeycomb briquette added into the compound acid is 30-100mg/min. Preferably, in step S1, the thermosetting phenolic resin powder has a particle size of less than 200 μm. Preferably, in step S1, the mass ratio of the honeycomb briquette to the thermosetting phenolic resin powder is (2:8) - (5:5). Preferably, in the step S1, the block copolymer comprises at least one of ：PEO100-PPO65-PEO100、PEO20-PPO70-PEO20、PEO141-PPO44-PEO141、PMMA-PEO, and the nitrogen source comprises at least one of polyaniline, ammonium nitrate, urea and amino acid. Preferably, in step S1, the washing treatment comprises alternately washing with deionized water and ethanol. Preferably, in the step S2, the temperature of the crosslinking treatment is 300-400 ℃ and the time is 3-5h, and the carbonization treatment comprises heating to 1000-1500 ℃ at the speed of 5 ℃ per minute, carbonizing for 2-4h, and naturally cooling to room temperature in an argon atmosphere. In a second aspect, the present invention provides a low temperature hard carbon, which is produced by the above production method. In a third aspect, the present inventi