CN118513549B

CN118513549B - A soluble copper-based composite material and its preparation method and application

Info

Publication number: CN118513549B
Application number: CN202410822593.3A
Authority: CN
Inventors: 赵佳欢; 张祥功; 魏冰歆; 王洋洋; 周思思
Original assignee: Wuhan Research Institute Of Marine Electric Propulsion No 712 Research Institute Of China Shipbuilding Corp
Current assignee: Wuhan Research Institute Of Marine Electric Propulsion No 712 Research Institute Of China Shipbuilding Corp
Priority date: 2024-06-25
Filing date: 2024-06-25
Publication date: 2025-09-12
Anticipated expiration: 2044-06-25
Also published as: CN118513549A

Abstract

The invention discloses a soluble copper-based composite material which is a sheet-shaped material with the thickness of 4-10 mu m, and consists of 60-90 wt% of copper powder, 8-38 wt% of a binder and 2-5 wt% of a conductive agent, wherein the binder is sodium alginate, the copper powder consists of two different copper powders with the particle diameters of 0.2 mu m and 1.1 mu m according to the weight ratio of 1-5:1, the conductive agent is one or more of carbon nano tubes, carbon black and graphene, and the preparation method and application of the composite material.

Description

Soluble copper-based composite material and preparation method and application thereof

Technical Field

The invention belongs to the field of electrochemical energy storage, and particularly relates to a soluble copper-based composite material, a preparation method thereof and a current collector for a lithium battery cathode.

Background

With the increasing environmental awareness, the recycling of renewable new energy has become a core industry for the world's competitive development. In recent years, the market share of new energy lithium battery automobiles is rising year by year, and meanwhile, the dependence of wind power and solar power plants on the lithium battery energy storage technology is also increasingly enhanced, which undoubtedly promotes the vigorous demand on the lithium battery energy storage technology. As an indispensable key component of the new energy lithium battery, the market demand of the cathode current collector copper foil material is also rapidly increased, and the cathode current collector copper foil material becomes an important force for promoting the sustainable development of the new energy industry.

At present, copper foil is used as a main material of a negative electrode current collector, but the existing copper foil is used as a negative electrode current collector, although copper is an excellent metal conductor with conductivity inferior to silver, and is abundant in resources and low in cost and easy to obtain, under some special processes, such as production of rolled copper foil, the manufacturing cost is relatively high, the price of pure copper is 2-3 times that of pure aluminum, in addition, due to the fact that the surface properties of the copper foil and the surface properties of a negative electrode material are different, in general, the bonding strength of a negative electrode adhesive and the surface of the copper foil has a certain problem, the negative electrode material is easy to peel, and in some special fields, a lithium battery is used as endurance power, but in order to protect the secret of special equipment, a self-destruction procedure is needed for the lithium battery of the special equipment, and the copper foil is difficult to self-destroy, so that the information of the special equipment is presumed through analysis of the lithium battery, and the risk of leakage is generated.

Disclosure of Invention

Based on the problems that the existing copper foil is high in preparation cost, certain in contact area and adhesion with a negative electrode material and difficult to self-destroy and cause easy leakage, one of the purposes of the invention is to provide a soluble copper-based composite material which can be used as a current collector material for replacing the copper foil, is easy to dissolve when meeting water, can realize complete dissolution of the copper foil under water environment and realize complete self-destruction of an electric device, and can be well bonded with the electrode material, so that the bonding strength of the negative electrode material and the copper-based composite material can be effectively improved, the green recovery of the copper foil can be realized, and the recovery is not performed by adopting an organic solvent.

The technical scheme includes that the soluble copper-based composite material is a sheet-shaped material with the thickness of 4-10 mu m, the content of each component is composed of 60-90 wt% of copper powder, 8-38 wt% of binder and 2-5 wt% of conductive agent according to weight percentage, the binder is sodium alginate, the copper powder is composed of two different copper powders with the particle sizes of 0.2 mu m and 1.1 mu m according to the weight ratio of 1-5:1, the density of the composite material can be guaranteed through different particle size grading, the viscosity performance can be further improved, the conductivity performance is improved, the proportion of copper powders with different particle sizes is equal to copper powder, and the conductive agent is one or more of carbon nano tubes, carbon black and graphene. The proportion of the copper powder to the binder and the conductive agent can achieve the same or slightly better conductive performance as the copper foil within a certain range.

Further, the conductive agent is a mixture of graphene and carbon black in a weight ratio of 1:2-5, or a mixture of carbon nano tube and carbon black in a weight ratio of 1:2-5. The graphene is a sheet material, the carbon black is granular, the carbon nano tube is of a tubular structure, and the granular structure, the two-position sheet structure and the tubular structure are matched for use, so that the conductivity can be improved, and the strength of the composite material can be also improved.

Further, the copper powder content is 80wt%, the binder content is 17wt%, and the conductive agent content is 3wt%. The proportion of the content can ensure good conductivity, and the obtained copper-based composite material and the anode material have good bonding strength.

The second purpose of the invention is to provide a preparation method of the soluble copper-based composite material, which comprises the following steps:

(1) Weighing 40-80 wt% of copper powder with the particle size of 0.2 mu m, 16-40 wt% of copper powder with the particle size of 1.1 mu m, 3wt% of conductive agent and 17wt% of sodium alginate according to a certain proportion, vibrating and mixing the materials in a ball milling mixing pipe to obtain mixed powder;

(2) Adding a proper amount of ultrapure water into the mixed powder, vibrating and mixing again until slurry with proper consistency is formed, controlling the viscosity of the slurry to 1300-160 mpa.s, and ensuring proper viscosity to be beneficial to coating and forming

(3) The method comprises the steps of using glass as a substrate, ensuring the surface of the substrate to be smooth and clean, uniformly coating prepared slurry on the glass substrate by using a coating scraper, putting the coated glass into a vacuum oven at 50-90 ℃ for drying for 2-10 hours, ensuring the slurry to be completely solidified, and drying at 60 ℃ for 8 hours.

(4) And rolling and stripping the dried copper-based composite material, controlling the thickness, and cutting according to the requirement to obtain the soluble copper-based composite material with the required length and width.

The invention further provides a current collector of the soluble copper-based composite material for the negative electrode of the lithium battery.

The fourth object of the present invention is to provide a lithium battery employing the above current collector.

The beneficial technical effects obtained by the invention are as follows:

The copper-based composite material provided by the invention has excellent dissolubility in water environment, so that the copper-based composite material is particularly suitable for key component parts of lithium batteries in marine special devices. Under specific application scenes, particularly when special equipment faces potential leakage risks, the lithium battery can realize self-destruction through a complete water-soluble mechanism, so that absolute safety of sensitive information is ensured. The technical breakthrough not only widens the application field of the copper-based composite material, but also provides powerful technical guarantee for the safety of marine special equipment. Through an accurate preparation process and a unique dissolution mechanism, the lithium battery can be dissolved rapidly and thoroughly under extreme conditions, and possible information leakage and environmental pollution risks are avoided.

The copper-based composite material provided by the invention can have good binding force and binding strength with the anode material. The copper-based composite material is formed by precisely bonding copper powder and conductive agent powder through a specific binder, and the negative electrode material is formed by precisely bonding powder additives such as negative electrode active material powder, conductive agent and the like through the binder. In the hot pressing process of lithium battery slurry, powder particles of the two materials can be compatible and closely contacted with each other, so that the contact area is effectively increased. The design not only enhances the bonding strength between the copper-based composite material and the negative electrode material, but also effectively reduces the interface impedance between the copper foil and the negative electrode material, and remarkably improves the overall performance of the lithium battery.

According to the invention, the particle size ratio of the copper powder to the conductive agent powder is accurately regulated, so that the conductive performance of the copper-based composite material is obviously improved, and the conductive performance of the copper-based composite material reaches the level equivalent to that of a copper foil current collector. Meanwhile, the copper-based composite material also has excellent water solubility, and provides unique advantages for specific application scenes.

According to the invention, the conductive agent and a proper amount of binder are added into the copper powder to be used as the components, so that the copper powder is reduced compared with the copper material used for pure copper foil, and the preparation method is relatively simple and the preparation cost is relatively low.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the following examples.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. It is to be understood that the following description is intended to be illustrative of the invention and not restrictive.

The materials and equipment used in the present invention are commercially available or are those commonly used in the art, and the methods described in the examples are those commonly used in the art unless otherwise specified.

The following is further described in connection with specific embodiments.

Example 1

The preparation method of the soluble copper-based composite material comprises the steps of weighing 40wt% of copper powder with the particle size of 0.2 mu m, 40wt% of copper powder with the particle size of 1.1 mu m, 1wt% of graphene, 2wt% of carbon black and 17wt% of sodium alginate, vibrating and mixing the materials in a ball milling mixing tube to uniformly mix the materials to obtain mixed powder, adding a proper amount of ultrapure water into the mixed powder, vibrating and mixing again until the viscosity of the formed slurry is 1400mpa.s, taking glass as a substrate, ensuring that the surface of the substrate is flat and clean, uniformly smearing the prepared slurry on the substrate by using a coating scraper, drying the coated glass in a vacuum oven at 60 ℃ for 8 hours, ensuring that the slurry is completely solidified and tightly combined on the glass substrate, rolling the dried glass, controlling the thickness of the copper-based composite material, stripping, and cutting according to requirements to obtain the soluble copper-based composite material with the required length and width. The powder and copper powder of the conductive agent realize multi-stage grain size grading, so that the compactness of the copper-based composite material is improved, and the conductivity is improved.

Resistivity test the copper-based composite of example 1 was used to evaluate the conductivity of a current collector by performing a four-wire-based copper foil resistivity test method. A copper matrix composite sample was connected to a four wire resistance meter using wires. Ensure firm connection and good contact. Four-wire methods require two pairs of wires, one pair for carrying current (current lines) and the other pair for measuring voltage (voltage lines). Suitable test parameters, such as current magnitude, test time, etc., are set according to the dimensions (length, cross-sectional area) and expected resistivity range of the copper-based composite sample. And (5) turning on a power supply and starting the four-wire resistance measuring instrument. Testing was started according to the instrument instructions. The instrument will automatically deliver current to the copper matrix composite sample and measure the voltage. After the test is completed, the instrument will display the resistance value of the copper-based composite sample. This value is recorded and used for subsequent calculations. Calculating the resistivity ρ=r×s/L, wherein R is the measured resistance value, S is the cross-sectional area of the copper-based composite sample, and L is the length of the copper-based composite sample.

The water solubility test of the copper-based composite material comprises the steps of taking the prepared copper-based composite material as a test sample, putting the prepared copper-based composite material into a certain volume of aqueous solution, keeping the aqueous solution under magnetic stirring, observing whether the copper-based composite material is completely dissolved, partially dissolved or not dissolved after 10 minutes, wherein the complete dissolution refers to the condition that no block or sheet-shaped material exists, the materials dissolved in the aqueous solution are uniformly dispersed, the partial dissolution refers to the condition that the solution has a piece-shaped block material, the non-dissolution refers to the condition that the negative electrode slurry on the copper-based composite material sheet does not dissolve, and the complete dissolution is marked as 3, the partial dissolution is marked as 2 and the non-dissolution is marked as 1 for convenience of recording, and the data of specific examples are shown in the following table.

Example 2

The preparation method of the soluble copper-based composite material comprises the steps of weighing 60wt% of copper powder with the particle size of 0.2 mu m,20 wt% of copper powder with the particle size of 1.1 mu m, 1wt% of graphene, 2wt% of carbon black and 17wt% of sodium alginate, vibrating and mixing the materials in a ball milling mixing tube to uniformly mix the materials to obtain mixed powder, adding an appropriate amount of ultrapure water into the mixed powder, vibrating and mixing again until the viscosity of the formed slurry is 1300mpa.s, taking glass as a substrate, ensuring that the surface of the substrate is flat and clean, uniformly smearing the prepared slurry on the substrate by using a coating scraper, drying the coated glass in a vacuum oven at 50 ℃ for 10 hours, ensuring that the slurry is completely solidified and tightly combined on the glass substrate, rolling the dried glass, controlling the thickness of the copper-based composite material, stripping and cutting according to requirements to obtain the soluble copper-based composite material with the required length and width.

Example 3

The preparation method of the soluble copper-based composite material comprises the steps of weighing 70wt% of copper powder with the particle size of 0.2 mu m, 14wt% of copper powder with the particle size of 1.1 mu m, 1wt% of graphene, 2wt% of carbon black and 17wt% of sodium alginate, vibrating and mixing the materials in a ball milling mixing tube to uniformly mix the materials to obtain mixed powder, adding an appropriate amount of ultrapure water into the mixed powder, vibrating and mixing again until the viscosity of the formed slurry is 1500mpa.s, taking glass as a substrate, ensuring that the surface of the substrate is flat and clean, uniformly smearing the prepared slurry on the substrate by using a coating scraper, drying the coated glass in a vacuum oven at 60 ℃ for 8 hours, ensuring that the slurry is completely solidified and tightly combined on the glass substrate, rolling the dried glass, controlling the thickness of the copper-based composite material, stripping and cutting according to requirements to obtain the soluble copper-based composite material with the required length and width.

Example 4

The preparation method of the soluble copper-based composite material comprises the steps of weighing 80wt% of copper powder with the particle size of 0.2 mu m, 16wt% of copper powder with the particle size of 1.1 mu m, 1wt% of graphene, 2wt% of carbon black and 17wt% of sodium alginate, vibrating and mixing the materials in a ball milling mixing tube to uniformly mix the materials to obtain mixed powder, adding an appropriate amount of ultrapure water into the mixed powder, vibrating and mixing again until the viscosity of the formed slurry is 160 mpa.s, taking glass as a substrate, ensuring that the surface of the substrate is flat and clean, uniformly smearing the prepared slurry on the substrate by using a coating scraper, putting the coated glass into a vacuum oven with the temperature of 80 ℃ for drying for 9 hours, ensuring that the slurry is completely solidified and tightly combined on the glass substrate, rolling the dried glass, controlling the thickness of the copper-based composite material, stripping and cutting according to requirements to the requirements to obtain the soluble copper-based composite material with the required length and width.

Example 5

The preparation method comprises the steps of weighing 80wt% of copper powder with the particle size of 1.1 mu m,40 wt% of copper powder with the particle size of 1.1 mu m, 1wt% of graphene, 2wt% of carbon black and 17wt% of sodium alginate, vibrating and mixing the materials in a ball milling mixing tube to uniformly mix the materials to obtain mixed powder, adding an appropriate amount of ultrapure water into the mixed powder, vibrating and mixing again until the viscosity of the formed slurry is 1400mpa.s, taking glass as a substrate, ensuring that the surface of the substrate is flat and clean, uniformly smearing the prepared slurry on the substrate by using a coating scraper, drying the coated glass in a vacuum oven at 60 ℃ for 8 hours, ensuring that the slurry is completely solidified and tightly combined on the glass substrate, rolling the dried glass, controlling the thickness of the copper-based composite, stripping, and cutting according to requirements to obtain the soluble copper-based composite with the required length and width.

Example 6

The preparation method of the soluble copper-based composite material comprises the steps of weighing 60wt% of copper powder with the particle size of 0.2 mu m, 20wt% of copper powder with the particle size of 1.1 mu m, 1wt% of carbon nano tube, 2wt% of carbon black and 17wt% of sodium alginate, vibrating and mixing the carbon nano tube and the carbon black in a ball milling mixing tube to uniformly mix the materials to obtain mixed powder, adding an appropriate amount of ultrapure water into the mixed powder, vibrating and mixing again until the viscosity of the formed slurry is 1400mpa.s, taking glass as a substrate, ensuring that the surface of the substrate is flat and clean, uniformly smearing the prepared slurry on the substrate by using a coating scraper, drying the coated glass in a vacuum oven at 60 ℃ for 8 hours, ensuring that the slurry is completely solidified and tightly combined on the glass substrate, rolling the dried glass, controlling the thickness of the copper-based composite material, stripping, and cutting according to requirements to obtain the soluble copper-based composite material with the required length and width.

Example 7

The preparation method comprises the steps of weighing 60wt% of copper powder with the particle size of 0.2 mu m, 20wt% of copper powder with the particle size of 1.1 mu m, 3wt% of carbon black and 17wt% of sodium alginate, uniformly mixing the materials in a ball milling mixing tube to obtain mixed powder, adding a proper amount of ultrapure water into the mixed powder, vibrating and mixing again until the viscosity of the formed slurry is 1400mpa.s, taking glass as a substrate, ensuring the surface of the substrate to be flat and clean, uniformly smearing the prepared slurry on the substrate by using a coating scraper, putting the coated glass into a vacuum oven at 60 ℃ for drying for 8 hours, ensuring the slurry to be completely solidified and tightly combined on the glass substrate, rolling the dried glass, controlling the thickness of the copper-based composite, stripping and cutting according to requirements to obtain the soluble copper-based composite with the required length and width.

Comparative example 1, weighing 55wt% of copper powder with the particle size of 0.2 mu m, 2wt% of graphene, 3wt% of carbon black and 40wt% of sodium alginate, vibrating and mixing and grinding the graphene and the carbon black with the particle size of 0.05-0.5 mu m in a ball milling mixing tube to uniformly mix the materials to obtain mixed powder, adding a proper amount of ultrapure water into the mixed powder, vibrating and mixing and grinding again until the viscosity of the formed slurry is 1400mpa.s, taking glass as a substrate, ensuring that the surface of the substrate is smooth and clean, uniformly smearing the prepared slurry on the substrate by using a coating scraper, drying the coated glass in a vacuum oven at 60 ℃ for 8 hours, ensuring that the slurry is completely solidified and tightly combined on the glass substrate, rolling the dried glass, controlling the thickness of the copper-based composite material, stripping and cutting according to requirements to obtain the soluble copper-based composite material with the required length and width.

The preparation method comprises the steps of weighing 90wt% of copper powder with the particle size of 0.2 mu m, 5wt% of carbon black and 17wt% of sodium alginate, vibrating and mixing the graphene and the carbon black in a ball milling mixing tube to obtain mixed powder, adding a proper amount of ultrapure water into the mixed powder, vibrating and mixing again until the viscosity of the formed slurry is 1400mpa.s, selecting glass as a substrate to ensure that the surface of the substrate is smooth and clean, uniformly smearing the prepared slurry on the substrate by using a coating scraper, putting the coated glass into a vacuum oven at 60 ℃ for drying for 8 hours to ensure that the slurry is completely solidified and tightly combined on the glass substrate, rolling the dried glass, controlling the thickness of the copper-based composite material, stripping and cutting according to requirements to obtain the soluble copper-based composite material with the required length and width.

Comparative example 3a pure copper foil of the same dimensions as in example 1 was selected for testing.

The physical properties of each of the examples and comparative examples are shown in the following table.

。

From the data in the table above, examples 1-3 compare the effect of copper powders of different particle size fractions on the conductivity, and copper powders of different particle sizes have a significant effect on the conductivity of copper-based composites.

The data of examples 4-5 are compared, copper powders with different particle sizes are used as compositions to have important influence on the conductivity, and the data of examples 4-5 are compared with the data of examples 1-3, so that different particle size gradations can be obtained, and the conductivity can be improved.

The data of example 6 is mainly compared with example 2, and the addition of different conductive agents results in different conductive properties.

The comparison of the data of comparative examples 1-2 with the data of examples 1-5 shows that different component composition ratios have important influence on the conductivity.

In comparison with examples 1-5 and comparative example 3, the copper-based composite material has slightly poorer conductivity than the copper foil, but can achieve equivalent conductivity, has solubility, and further expands the selection, research and development of current collectors and application scenes.

The present application is not limited to the above embodiment. The above embodiments are merely examples, and embodiments having substantially the same configuration and the same effects as those of the technical idea within the scope of the present application are included in the technical scope of the present application. Further, various modifications that can be made to the embodiments and other modes of combining some of the constituent elements in the embodiments, which are conceivable to those skilled in the art, are also included in the scope of the present application within the scope not departing from the gist of the present application.

Claims

1. A soluble copper-based composite material, characterized in that it is a sheet material with a thickness of 4 to 10 μm, composed of 60 to 90 wt% copper powder, 8 to 38 wt% binder, and 2 to 5 wt% conductive agent; the binder is sodium alginate, the copper powder is composed of two different copper powders with particle sizes of 0.2 μm and 1.1 μm, respectively, in a weight ratio of 1 to 5:1, and the conductive agent is one or more of carbon nanotubes, carbon black, and graphene.

2. A soluble copper-based composite material according to claim 1, characterized in that the conductive agent is a mixture of graphene and carbon black in a weight ratio of 1:2 to 5, or a mixture of carbon nanotubes and carbon black in a weight ratio of 1:2 to 5.

3. The soluble copper-based composite material according to claim 2, characterized in that the copper powder content is 80wt%, the binder content is 17wt%, and the conductive agent content is 3wt%.

4. A method for preparing the soluble copper-based composite material according to claim 1, characterized in that the steps are as follows:

(1) Weigh copper powder, conductive agent and sodium alginate in proportion, vibrate and grind them in a ball mill mixing tube, and mix them evenly to obtain a mixed powder;

(2) Add ultrapure water to the mixed powder and vibrate and grind again until a slurry with a viscosity of 1300-1600 mPa.s is formed;

(3) Use glass as the substrate, ensure that the substrate surface is flat and clean, and use a coating scraper to evenly apply the prepared slurry on the glass substrate; place the coated glass in a vacuum oven at 50-90°C and dry for 2-10 hours to ensure that the slurry is completely cured;

(4) The dried copper-based composite material is rolled, peeled, and cut to obtain a soluble copper-based composite material.

5. A soluble copper-based composite material as claimed in claim 1 used as a current collector for a negative electrode of a lithium battery.

6. A lithium battery, characterized by using the current collector according to claim 5.