CN-116053706-B - Ternary lithium battery diaphragm slurry and preparation method thereof

CN116053706BCN 116053706 BCN116053706 BCN 116053706BCN-116053706-B

Abstract

The invention discloses ternary lithium battery diaphragm slurry and a preparation method thereof, which belong to the technical field of lithium batteries and comprise the following raw materials in parts by mass: 50-70 parts of composite adhesive, 200-300 parts of N-methyl pyrrolidone, 0.4-0.6 part of modified graphene oxide, 60-65 parts of aromatic auxiliary agent, 2-5 parts of ceramic powder and 300-400 parts of DMF (dimethyl formamide), and the preparation method comprises the following steps: the composite adhesive is dissolved in N-methylpyrrolidone, modified graphene oxide is added, methanol is used for precipitation and filtration after reaction, filter residues are washed and dried by methanol and water, then the filter residues are dissolved in DMF, ternary lithium battery diaphragm slurry is obtained by ultrasound, the composite adhesive is used for improving the thermal stability of a polymer, and the incompatibility of the composite adhesive and an aromatic auxiliary agent and the addition of the modified graphene oxide can improve the ion passing rate of a lithium battery.

Inventors

LI WANGYANG
LIU ZHIQIANG
LIU MENGRU
ZHANG QIANG
HU WEI
REN FENGMEI
XU WEIBING
ZHOU ZHENGFA
WU LEI
ZHANG DESHUN
WANG RUOYU
LI KUN

Assignees

界首市天鸿新材料股份有限公司

Dates

Publication Date: 20260505
Application Date: 20221229

Claims (4)

1. The ternary lithium battery diaphragm slurry is characterized by comprising, by mass, 50-70 parts of a composite adhesive, 200-300 parts of N-methylpyrrolidone, 0.4-0.6 part of modified graphene oxide, 60-65 parts of an aromatic auxiliary agent, 2-5 parts of ceramic powder and 300-400 parts of DMF; the preparation of the modified graphene oxide comprises the following steps: Step A1, adding graphene oxide, (3-mercaptopropyl) trimethylsilane into tetrahydrofuran, and reacting for 20-22 hours at 55-65 ℃ to obtain a mixed solution A; Step A2, cooling the mixed solution A to room temperature, filtering, and soaking the obtained filter residues with 30-35% hydrogen peroxide solution for 20-22h to obtain a mixed solution B; Step A3, filtering the mixed solution B, and then placing the obtained filter residue into a LiOH aqueous solution with the concentration of 0.15-0.25mol/L for 3-4 hours to obtain a mixed solution C; step A4, filtering the mixed solution C, washing the mixed solution C with water and methanol for three times respectively, and drying the mixed solution C for 20 to 22 hours under vacuum to obtain modified graphene oxide; the composite adhesive is obtained by mixing polyimide P84 and PVDF-HFP according to a mass ratio of 4:6; The aromatic auxiliary agent is obtained by mixing 4, 4-diamino diphenyl sulfone and diphenyl sulphonyl imine according to a mass ratio of 3.5:1.4.
2. The ternary lithium battery diaphragm slurry of claim 1, wherein the mass ratio of graphene oxide to (3-mercaptopropyl) trimethylsilane to tetrahydrofuran to hydrogen peroxide to LiOH aqueous solution is 8-12:95-105:95-105:100-110:100-110.
3. The preparation method of the ternary lithium battery diaphragm slurry, as claimed in claim 1, is characterized by comprising the following steps: Step B1, adding a composite adhesive and N-methylpyrrolidone into a reaction vessel, uniformly stirring at room temperature, adding an aromatic auxiliary agent and modified graphene oxide after complete dissolution, and reacting for 6-8 hours under the protection of argon at 100-120 ℃ to obtain a reaction solution; Step B2, cooling the reaction liquid to 60-65 ℃, transferring the reaction liquid into methanol, filtering after precipitation is completely separated out, washing filter residues with methanol and water for 3-4 times respectively, drying for 10-12 hours at 60-65 ℃, and finally drying for 20-22 hours at 100-105 ℃ in vacuum for standby to obtain a modified composite electrolyte; And B3, dissolving the modified composite electrolyte in DMF at 60-65 ℃, carrying out ultrasonic treatment for 15-20min, and adding ceramic powder into the modified composite electrolyte solution to obtain the ternary lithium battery diaphragm slurry.
4. The method for preparing the ternary lithium battery diaphragm slurry according to claim 3, wherein the volume ratio of the reaction solution to the methanol in the step B2 is 1:10.

Description

Ternary lithium battery diaphragm slurry and preparation method thereof Technical Field The invention belongs to the technical field of lithium batteries, and particularly relates to ternary lithium battery diaphragm slurry and a preparation method thereof. Background The rapid development of new energy industry brings about unprecedented opportunities for the lithium ion battery industry and also puts higher requirements for the lithium ion battery industry. The traditional lithium ion battery separator is mostly a polyolefin separator, but potential safety hazards easily occur in the use process of the lithium ion battery due to poor thermal stability of polyolefin and easy thermal shrinkage, so that a polymer with excellent heat resistance is often coated on the surface of the polyolefin separator to form a heat-resistant three-dimensional network structure, but the ion passing rate is greatly reduced due to a compact network structure, so that the capacity and the efficiency of the battery are affected. Disclosure of Invention The invention aims to provide ternary lithium battery diaphragm slurry, which is used for solving the problems of poor thermal stability and low ion passing rate of a lithium battery diaphragm in the background technology. The aim of the invention can be achieved by the following technical scheme: 50-70 parts of composite adhesive, 200-300 parts of N-methyl pyrrolidone, 0.4-0.6 part of modified graphene oxide, 60-65 parts of aromatic auxiliary agent, 2-5 parts of ceramic powder and 300-400 parts of DMF (dimethyl formamide); Further, the preparation of the modified graphene oxide comprises the following steps: Step A1, adding graphene oxide, (3-mercaptopropyl) trimethylsilane into tetrahydrofuran, and reacting for 20-22 hours at 55-65 ℃ to obtain a mixed solution A; Step A2, cooling the mixed solution A to room temperature, filtering, and soaking the obtained filter residue with 30-35% hydrogen peroxide solution for 20-22h to fully convert mercapto into sulfonic acid group to obtain mixed solution B; Step A3, filtering the mixed solution B, and then placing the obtained filter residue into 0.15-0.25 mol/L of L iOH aqueous solution for 3-4h for lithium exchange to obtain mixed solution C; And step A4, filtering the mixed solution C, respectively washing with water and methanol for three times, and drying for 20-22 hours under vacuum to obtain the modified graphene oxide, wherein the graphene oxide has high specific surface area and good electrochemical, mechanical and thermal stability properties, so that the thermal stability of a lithium battery diaphragm can be obviously improved by adding the modified graphene oxide into lithium battery diaphragm slurry. Further, the mass ratio of graphene oxide to (3-mercaptopropyl) trimethylsilane to tetrahydrofuran to the mass ratio of hydrogen peroxide solution to the mass ratio of L iOH aqueous solution is 8-12:95-105:95-105:100-110:100-110. Further, the composite adhesive is obtained by mixing polyimide P84 and PVDF-HFP according to a mass ratio of 4:6. Further, the aromatic auxiliary agent is obtained by mixing 4, 4-diamino diphenyl sulfone and diphenyl sulphonyl imine according to a mass ratio of 3.5:1.4, the aliphatic flexible PVDF-HFP adhesive and the aromatic rigid polymer diphenyl sulphonyl imine are incompatible, and the strong polar lithium sulfonate groups on the modified graphene oxide and the strong polar double sulphonyl imine groups in the composite adhesive are subjected to strong interaction, so that in the solvent volatilization process when the lithium battery diaphragm is prepared, the aliphatic flexible PVDF-HFP adhesive and the aromatic rigid polymer diphenyl sulphonyl imine are subjected to microphase separation to generate a pore structure so as to improve the ion passing rate of the lithium battery. The preparation method of the ternary lithium battery diaphragm slurry comprises the following steps: Step B1, adding a composite adhesive and N-methyl pyrrolidone into a reaction vessel, adding an aromatic auxiliary agent and modified graphene oxide after complete dissolution, and reacting for 6-8 hours under the protection of argon at 100-120 ℃ to obtain a reaction solution; Step B2, cooling the reaction liquid to 60-65 ℃, transferring the reaction liquid into methanol, filtering after precipitation is completely separated out, washing filter residues with methanol and water for 3-4 times respectively, drying for 10-12 hours at 60-65 ℃, and finally drying for 20-22 hours at 100-105 ℃ in vacuum for standby to obtain a modified composite electrolyte; And B3, dissolving the modified composite electrolyte in DMF at 60-65 ℃, carrying out ultrasonic treatment for 15-20 min, and then adding ceramic powder into the modified electrolyte to obtain the ternary lithium battery diaphragm slurry. Further, the volume ratio of the reaction solution to the methanol in the step B2 is 1:10. The invention has the beneficial effects that: A