CN-122013265-A - Method for preparing high-conductivity lithium electric copper foil by hydroxylation modified graphene codeposition

Abstract

The invention discloses a method for preparing high-conductivity lithium-ion copper foil by hydroxylation modified graphene codeposition, which comprises the following steps of S1, adopting an improved Hummers method to synthesize graphene oxide, adding natural graphite and NaNO 3 into mixed acid of concentrated sulfuric acid and phosphoric acid under ice bath, stirring for 1 hour to fully disperse graphite, adding KMnO 4 for three times, continuously stirring for 20 minutes, removing the ice bath, heating a reaction system to 50 ℃, continuously stirring for 24 hours, gradually changing a solution into a brownish black sticky matter, adding 30% H 2 O 2 , changing the color of the solution from brownish black to bright yellow, washing a product with 5% HCl solution for 3 times, and washing the product with deionized water to be neutral for later use. According to the invention, the graphene subjected to hydroxylation treatment is introduced in the preparation process of the electrolytic copper foil, and the copper and the functionalized graphene are synchronously deposited on the surface of the cathode by utilizing an electrochemical codeposition technology, so that the copper foil for the lithium ion battery, which has high conductivity, high mechanical strength and good interface stability, is obtained.

Inventors

• FU ZHENGBING
• TAO JUN
• Tong Kaiwen
• WANG WEI
• ZHANG XIN
• XU ZHIQIANG

Assignees

• 江西鑫铂瑞科技股份有限公司

Dates

Publication Date

20260512

Application Date

20260303

Claims (5)

1. 1. The method for preparing the high-conductivity lithium electric copper foil by the hydroxylation modified graphene codeposition is characterized by comprising the following steps of: S1, synthesizing graphene oxide by adopting an improved Hummers method, namely adding natural graphite and NaNO 3 into mixed acid of concentrated sulfuric acid and phosphoric acid under ice bath, stirring for 1 hour to fully disperse the graphite, adding KMnO 4 three times, continuously stirring for 20 minutes, removing the ice bath, heating a reaction system to 50 ℃, continuously stirring for 24 hours, gradually changing a solution into a brownish black thick substance, adding 30% H 2 O 2 , changing the color of the solution from brownish black to bright yellow, washing a product with 5% HCl solution for 3 times, and washing the product with deionized water until the product is neutral for later use; S2, preparing a copper foil electrolyte, namely mixing a basic electrolyte and an additive; Wherein the basic electrolyte consists of CuSO 4 ·5H 2 O、H 2 SO 4 , additives of chloride ions, sodium polydithio-dipropyl sulfonate, collagen and polyethylene glycol; S3, dispersing the modified graphene in the electrolyte, namely slowly adding the graphene dispersion into the electrolyte to ensure that the mass concentration of the graphene is 5%, and pneumatically stirring to obtain the graphene, wherein the electrolyte maintains the flow of 52-55 m 3 /h in the use process, so that the graphene is prevented from settling; and S4, finally, carrying out foil production by using a foil production machine.
2. 2. The method for preparing the high-conductivity lithium electrodeposited copper foil by the co-deposition of the hydroxylated modified graphene according to claim 1, wherein in the step S1, the mass ratio of the natural graphite to the NaNO 3 is 2:1.
3. 3. The method for preparing the high-conductivity lithium electrodeposited copper foil by the hydroxylation modified graphene codeposition according to claim 1, wherein in the step S1, the volume ratio of concentrated sulfuric acid to phosphoric acid is 12:1.
4. 4. The method for preparing the high-conductivity lithium electrodeposited copper foil by the co-deposition of the hydroxylated modified graphene according to claim 1, wherein in the step S2, the concentration of each component of a basic electrolyte is CuSO 4 ·5H 2 O：90 g/L、H 2 SO 4 :110 g/L, the concentration of each component of an additive is chloride ion 25: 25 mg/L, sodium polydithio-dipropyl sulfonate 12: 12 mg/L, collagen 8mg/L and polyethylene glycol 0.5: 0.5 mg/L.
5. 5. The method for preparing the high-conductivity lithium electrodeposited copper foil by the co-deposition of the hydroxylation modified graphene according to claim 1, wherein in the step S4, the current density of a cathode roller of a foil forming machine is 6500A/m 2 , and the linear speed is 12m/min, so that the copper foil is prepared.

Description

Method for preparing high-conductivity lithium electric copper foil by hydroxylation modified graphene codeposition Technical Field The invention relates to the technical field of copper foil electroplating, in particular to a method for preparing high-conductivity lithium electrodeposited copper foil by co-deposition of hydroxylated modified graphene. Background The lithium electric copper foil is one of key basic materials of the lithium ion battery and is mainly used as a negative current collector. It not only plays a role of carrying a negative electrode active material in a battery, but also collects electrons generated from the negative electrode active material (e.g., graphite, silicon carbon) and conducts them to an external circuit through a tab, so that it is required that the smaller the internal resistance thereof is, the better. The excessive internal resistance has the following defects that the voltage under the load is reduced rapidly, so that the battery cannot provide enough power, the voltage at the battery end is higher than the charge cut-off voltage, so that the BMS (battery management system) reduces the charging current in advance, the charging time is prolonged, the real quick charging cannot be realized, the excessive internal resistance causes severe heating of the high-internal-resistance battery core during the high-current charging and discharging, and the safety of the battery is influenced. The lithium electric copper foil is prepared by adopting an electrodeposition process at present, the purity of the copper foil is more than 98.5%, the resistance of the lithium electric copper foil is close to the theoretical resistance of copper, and the resistance improvement space is not large by improving the purity. Graphene is one of the best known materials for electrical conductivity (electron mobility much higher than copper). A layer of graphene conductive network is formed on the surface of the copper foil, so that a highway can be provided for electrons, and ohmic internal resistance is reduced. The conventional copper foil has a smooth surface and a limited contact area with the negative electrode active material (e.g., graphite particles). The graphene has a huge specific surface area and a unique two-dimensional structure, and the surface roughness and active sites can be increased when the graphene is coated on the copper foil, so that the contact internal resistance is reduced. Therefore, we propose a method for preparing high-conductivity lithium electrodeposited copper foil by hydroxylation modified graphene co-deposition to solve the above problems. Disclosure of Invention The invention aims to provide a method for preparing a high-conductivity lithium-ion-exchange copper foil by co-deposition of hydroxylated modified graphene, which aims to solve the problems in the prior art. In order to achieve the above purpose, the present invention provides the following technical solutions: A method for preparing high-conductivity lithium electric copper foil by hydroxylation modified graphene codeposition comprises the following steps: S1, synthesizing graphene oxide by adopting an improved Hummers method, namely adding natural graphite and NaNO 3 into mixed acid of concentrated sulfuric acid and phosphoric acid under ice bath, stirring for 1 hour to fully disperse the graphite, adding KMnO 4 three times, continuously stirring for 20 minutes, removing the ice bath, heating a reaction system to 50 ℃, continuously stirring for 24 hours, gradually changing a solution into a brownish black thick substance, adding 30% H 2O2, changing the color of the solution from brownish black to bright yellow, washing a product with 5% HCl solution for 3 times, and washing the product with deionized water until the product is neutral for later use; S2, preparing a copper foil electrolyte, namely mixing a basic electrolyte and an additive; Wherein the basic electrolyte consists of CuSO 4·5H2O、H2SO4, additives of chloride ions, sodium polydithio-dipropyl sulfonate, collagen and polyethylene glycol; S3, dispersing the modified graphene in the electrolyte, namely slowly adding the graphene dispersion into the electrolyte to ensure that the mass concentration of the graphene is 5%, and pneumatically stirring to obtain the graphene, wherein the electrolyte maintains the flow of 52-55 m < 3 >/h in the use process, so that the graphene is prevented from sedimentation; and S4, finally, carrying out foil production by using a foil production machine. Further, in the step S1, the mass ratio of the natural graphite to the NaNO 3 is 2:1. Further, in the step S1, the volume ratio of the concentrated sulfuric acid to the phosphoric acid is 12:1. Further, in the step S2, the concentration of each component of the basic electrolyte is CuSO 4·5H2O：90 g/L、H2SO4:110 g/L, and the concentration of each component of the additive is 25: 25 mg/L, 12: 12 mg/L of sodium polydithio-dipropyl sulfonate, 8mg/L of collagen and