CN-122025643-A - Phosphorus-carbon negative electrode water-based slurry and preparation method thereof

CN122025643ACN 122025643 ACN122025643 ACN 122025643ACN-122025643-A

Abstract

The invention discloses phosphorus-carbon negative electrode water-based slurry and a preparation method thereof, and belongs to the technical field of lithium battery materials. The preparation method comprises the steps of mixing a phosphorus-carbon material with a conductive agent to obtain a precursor, adding alkaline lithium salt into the precursor, reacting to obtain a mixture A, adding an acid-resistant polyacrylic acid binder into the mixture A, uniformly stirring to obtain a mixture B, adding a cellulose thickener into the mixture B, uniformly stirring to obtain a mixture C, and adding a rubber binder into the mixture C to obtain the phosphorus-carbon anode water-based slurry. According to the invention, through a specific process sequence of adding the conductive agent, stirring and then adding the alkaline lithium salt, a lithium phosphate fast ion conductor is generated on the surface of the phosphorus-carbon material in situ, the pH value of the slurry is regulated, and the slurry stability, the pole piece processability and the electrochemical performance of the battery are obviously improved by combining the use of the acid-resistant PAA binder.

Inventors

HAN XUERUI
RAO YUANYUAN
WANG ZHIQUAN
PENG YOUSHAN
Xia Linxuan
PENG NA
XIAO XIONG

Assignees

合肥国轩科宏新能源科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260416

Claims (11)

1. The preparation method of the phosphorus-carbon anode water-based slurry is characterized by comprising the following steps of: S1, mixing a phosphorus-carbon material with a conductive agent to obtain a precursor; s2, adding alkaline lithium salt into the precursor, and reacting to obtain a mixture A; s3, adding an acid-resistant polyacrylic acid binder into the mixture A and uniformly stirring to obtain a mixture B; s4, adding a cellulose thickener into the mixture B and uniformly stirring to obtain a mixture C; s5, adding a rubber binder into the mixture C to obtain the phosphorus-carbon anode water-based slurry.
2. The method according to claim 1, wherein the conductive agent is at least one of carbon nanotube, ketjen black, acetylene black, conductive carbon black, and graphene.
3. The method according to claim 1, wherein the alkaline lithium salt is at least one of lithium hydroxide and lithium carbonate.
4. The method according to claim 1, wherein the acid-resistant polyacrylic acid-based binder is polyacrylic acid or an acid-resistant salt derivative thereof.
5. The method according to claim 1, wherein in step S2, the reaction is performed at a temperature of 20 to 30 ℃ for a time of 40 to 60 minutes.
6. The preparation method according to claim 1, wherein the addition amount of the alkaline lithium salt is 0.1-0.3% of the mass of the phosphorus-carbon material; the cellulose thickener is sodium carboxymethyl cellulose, and the addition amount of the cellulose thickener is 0.6-2.4% of the mass of the phosphorus-carbon material; the rubber binder is styrene-butadiene latex, the solid content of the styrene-butadiene latex is 35-45%, and the addition amount of the styrene-butadiene latex is 1.62-1.66% of the mass of the phosphorus-carbon material; the addition amount of the conductive agent is 4.15-4.35% of the mass of the phosphorus-carbon material.
7. The method according to claim 1, wherein the pH of the phosphorus-carbon negative electrode aqueous slurry is 4 to 8.5.
8. The method according to claim 1, wherein the phosphorus-carbon anode aqueous slurry has a solid content of 34% to 55%.
9. A phosphorus carbon negative electrode aqueous slurry prepared by the preparation method according to any one of claims 1 to 8.
10. A phosphorus-carbon negative electrode sheet, comprising a current collector and a coating layer arranged on the current collector, wherein the coating layer is formed by coating and drying the phosphorus-carbon negative electrode aqueous slurry according to claim 9.
11. A lithium ion battery comprising the phosphorus-carbon negative electrode sheet of claim 10.

Description

Phosphorus-carbon negative electrode water-based slurry and preparation method thereof Technical Field The invention relates to the technical field of lithium battery materials, in particular to phosphorus-carbon negative electrode water-based slurry and a preparation method thereof. Background Lithium ion batteries are widely applied to the fields of portable electronic equipment, electric automobiles and large-scale energy storage as high-energy-density energy storage devices, and the improvement of energy density and multiplying power performance is always a research hot spot. The phosphorus-based negative electrode material is considered to be one of important directions for breaking through the performance bottleneck of the existing graphite negative electrode due to the advantages of high theoretical specific capacity, moderate lithium intercalation potential and the like. However, elemental phosphorus is easy to oxidize in air, an acidic environment is formed in the water system homogenization process, so that the conventional binder is deactivated, and further the problems of pole piece cracking, active substance defogging and the like are caused, so that the industrialized application of the phosphorus-carbon negative electrode material is severely restricted. To solve the above problems, researchers have attempted to isolate air oxidation by surface coating a phosphorus-carbon material, such as red phosphorus deposited on the surface of a porous carbon support and coating a fast ion conductor layer. However, due to the low melting point and sublimation temperature of red phosphorus, the traditional high-temperature coating process is difficult to realize uniform and compact coating, the surface of the phosphorus-carbon material still has a bare area, and the binder is invalid due to the local acidic environment when the water system is homogenized, so that the pole piece is easy to have defects of powder removal, cracking and the like. Therefore, how to solve the stability problem of the phosphorus-carbon material in the water system homogenization process while maintaining the high capacity advantage of the phosphorus-carbon material becomes a technical problem to be broken through in the field. Disclosure of Invention In view of the above, the invention provides a phosphorus-carbon negative electrode aqueous slurry and a preparation method thereof, wherein a specific process sequence of adding conductive agent, stirring and then adding alkaline lithium salt is adopted, a lithium phosphate fast ion conductor is generated on the surface of a phosphorus-carbon material in situ, the pH value of the slurry is regulated, and the slurry stability, the pole piece processability and the electrochemical performance of a battery are obviously improved by combining the use of an acid-resistant PAA (polyacrylic acid) binder. In order to achieve the above purpose, the invention adopts the following technical scheme: in a first aspect, the invention discloses a preparation method of phosphorus-carbon anode water-based slurry, which comprises the following steps: S1, mixing a phosphorus-carbon material with a conductive agent to obtain a precursor; s2, adding alkaline lithium salt into the precursor, and reacting to obtain a mixture A; s3, adding an acid-resistant polyacrylic acid binder into the mixture A and uniformly stirring to obtain a mixture B; s4, adding a cellulose thickener into the mixture B and uniformly stirring to obtain a mixture C; s5, adding a rubber binder into the mixture C to obtain the phosphorus-carbon anode water-based slurry. In a further scheme, the conductive agent is at least one of carbon nano tube, ketjen black, acetylene black, conductive carbon black and graphene. In a further scheme, the alkaline lithium salt is at least one of lithium hydroxide and lithium carbonate. Further proposal is that the acid-resistant polyacrylic acid binder is polyacrylic acid or acid-resistant salt derivatives thereof. In a further scheme, in the step S2, the reaction temperature is 20-30 ℃ and the reaction time is 40-60min. The addition amount of the alkaline lithium salt is 0.1-0.3% of the mass of the phosphorus-carbon material; The cellulose thickener is sodium carboxymethyl cellulose, and the addition amount of the cellulose thickener is 0.06-2.2% of the mass of the phosphorus-carbon material; The rubber binder is styrene-butadiene latex, the solid content of the styrene-butadiene latex is 35-45%, preferably 40%, and the addition amount of the styrene-butadiene latex is 1.62-1.66% of the mass of the phosphorus-carbon material; the addition amount of the conductive agent is 4.15-4.35% of the mass of the phosphorus-carbon material. Further proposal is that the pH value of the phosphorus-carbon anode water-based slurry is 4-8.5. When the pH value of the phosphorus-carbon anode water-based slurry is 4-8.5, the pH value of the slurry is obviously superior to the acidic environment with the pH value of