WO2023130827A1 - Electric conducting material and preparation method therefor - Google Patents

Abstract

An electric conducting material and a preparation method therefor. The electric conducting material comprises: porous carbon particles, holes of which are filled with zirconium nanoparticles; and graphene, loaded with the porous carbon particles. According to the electric conducting material, by means of design of the material and structure, the conductivity of the electric conducting material can be remarkably improved.

Description

A kind of conductive material and preparation method thereof technical field

The invention belongs to the technical field of new energy, and in particular relates to a conductive material and a preparation method thereof.

Background technique

Lithium-ion batteries have the advantages of high working voltage, large capacity, small size, light weight, and long cycle life, and are widely used in portable electronic products, electric bicycles, electric vehicles, and energy storage. Lithium-ion batteries generally include positive pole, negative pole, diaphragm and electrolyte; wherein, the coating of positive pole or negative pole at least includes active material, conductive agent and binding agent; the conductivity of conductive agent is one of the key factors affecting the performance of lithium-ion battery , the existing materials that can be used as conductive agents mainly include carbon black, graphite, vapor-phase grown nano-carbon fibers, and carbon nanotubes; Performance, but the conductive agent itself is inert and cannot provide capacity, so increasing the proportion of conductive materials will reduce the energy density of lithium-ion batteries.

In summary, the low conductivity of existing conductive materials still has an obvious restrictive effect on the further improvement of the performance of lithium-ion batteries. It is necessary to develop more efficient conductive materials, which can increase the overall conductivity of the positive and negative electrodes while reducing the dosage, thereby improving the capacity, rate and cycle performance of the battery.

Contents of the invention

The present invention aims to solve at least one of the technical problems in the above-mentioned prior art. For this reason, the present invention proposes a conductive material, through the design of the material and relative structure of each component, the conductivity of the above-mentioned conductive material can be significantly improved.

The present invention also proposes a preparation method of the above-mentioned conductive material.

The present invention also proposes a secondary battery having the above-mentioned conductive material.

According to one aspect of the present invention, a kind of conductive material is proposed, comprising:

Porous carbon particles, zirconium nanoparticles are distributed in the pores and surfaces of the porous carbon particles;

Graphene encapsulating the porous carbon particles.

According to a preferred embodiment of the present invention, it has at least the following beneficial effects:

(1) Graphene (flaky) can achieve "surface-point" contact with porous carbon particles, so that the resulting conductive material has a better conductive effect, that is, this contact method makes it easier to Form a conductive path, so when the above-mentioned conductive material is used to prepare the secondary battery pole piece, the amount of the conductive material can be reduced on the basis of ensuring the conductivity of the secondary battery pole piece; Build a conductive network in the pole piece of the secondary battery; realize long-distance conduction on the entire electrode.

(2) Graphene is also a kind of traditional conductive agent, but its planar structure will have a steric effect on the transmission of active ions (such as lithium ions in lithium-ion batteries), especially at high currents and rates. It is more obvious; the present invention makes above-mentioned conductive material form layered structure (graphene nano-sheet is overlapped each other in filtering, drying process) by the compound intermediate that forms with graphene wrapping porous carbon particle and zirconium nanoparticle, layered structure That is, the three-dimensional structure is equivalent to increasing the cross-sectional area of the conductive material, thereby improving the steric hindrance effect of graphene oxide.

(3) The zirconium nanoparticles fill the tiny pores on the surface of the porous carbon particles and reduce the impedance of the porous carbon particles, thereby improving the performance of the resulting conductive material.

(4) The conductive material provided by the present invention has extremely strong conductivity, so in the positive and negative plates of secondary batteries, the consumption of conductive agent can be reduced, the consumption of positive active material or negative active material can be increased, and then the secondary battery can be greatly improved. The volumetric energy density of the battery.

In some embodiments of the present invention, the conductive material has a layered structure.

In some embodiments of the invention, the porous carbon particles are soot particles.

In some embodiments of the present invention, the source of the soot particles is exhaust gas emitted by diesel vehicles.

In some embodiments of the present invention, the pretreatment of the soot particles includes sintering the collected soot particles.

In some embodiments of the present invention, the sintering atmosphere is air.

In some embodiments of the present invention, the sintering time is 4-8 hours.

In some embodiments of the present invention, the sintering temperature is 200-300°C.

The function of the sintering is to remove impurities therein.

The solid particles emitted by diesel vehicles are small in size and rich in carcinogenic organic substances such as polycyclic aromatic hydrocarbons, which are easily inhaled by people and cause serious diseases. Collecting exhaust particles and reusing them is a sustainable development method. Diesel engine exhaust emissions are mainly soot particles, which are conductive. Therefore, using the soot particles to prepare the conductive material not only reduces the cost of the battery, but also facilitates the secondary utilization of the soot particles.

In some embodiments of the present invention, the particle size of the conductive material is 30-40 nm.

In some embodiments of the present invention, the porosity of the conductive material is 60-70%.

In some embodiments of the present invention, the specific surface area of the conductive material is 450-550 m ² /g.

In some embodiments of the present invention, the mass ratio of the porous carbon particles to the zirconium nanoparticles is 5˜10:1.

In some embodiments of the present invention, the graphene comprises graphene oxide.

In some embodiments of the present invention, the graphene sheet diameter is 200-260 nm.

In some embodiments of the present invention, the mass ratio of the sum of the mass of the porous carbon particles and the zirconium nanoparticles to the graphene is 3-5:1.

According to another aspect of the present invention, a method for preparing the conductive material is proposed, comprising the following steps:

S1. Adding the porous carbon particles to the dispersion of the zirconium nanoparticles, and calcining the obtained solid after the reaction;

S2. The solid obtained in step S1 is wet-mixed with the graphene, and then the solvent is removed.

In some embodiments of the present invention, the dispersant of the zirconium nanoparticle dispersion is at least one of ethanol and water.

In some embodiments of the present invention, in the dispersion of zirconium nanoparticles, the ratio of the zirconium nanoparticles to the dispersant is 1-2 g: 100 mL.

In some embodiments of the present invention, the dispersion liquid of zirconium nanoparticles is prepared by adding the zirconium nanoparticles into a dispersant and stirring for about 30 minutes.

In some embodiments of the present invention, the mass ratio of the porous carbon particles to the zirconium nanoparticles is 5˜10:1.

In some embodiments of the present invention, the temperature of the reaction is 80-100°C.

In some embodiments of the present invention, the reaction time is 2-4 hours.

In some embodiments of the present invention, step S1 further includes adding a binder to the dispersion of zirconium nanoparticles before the reaction.

In some embodiments of the invention, the binder includes at least one of glucose and sucrose.

In some embodiments of the present invention, the mass ratio of the binder to the porous carbon particles is 1:10-20.

The binder can improve the cohesiveness between the zirconium nanoparticles and the porous carbon particles, and promote the former to fill in the pores of the latter, or be loaded on the surface of the latter;

During the calcination in step S1, the binder can also be carbonized into carbon with a loose structure, so as to improve the conductivity of the conductive material.

In some embodiments of the present invention, in step S1, washing and drying the solid obtained in the reaction are further included between the reaction and the calcination.

In some embodiments of the present invention, the washing solvent is acetone.

In some embodiments of the present invention, the drying temperature is about 50°C.

In some embodiments of the present invention, the drying time is 6-12 hours.

In some embodiments of the present invention, in step S1, the temperature of the calcination is 200-300°C.

In some embodiments of the present invention, in step S1, the calcination time is 2-4 hours.

In some embodiments of the present invention, in step S1, the calcination atmosphere is air atmosphere.

In some embodiments of the present invention, the method of wet mixing is: adding the solid obtained in step S1 to the organic dispersion of graphene.

In some embodiments of the present invention, the dispersant of the organic dispersion liquid is at least one of acetone, ethanol and methanol.

In some embodiments of the present invention, the mass ratio of the solid obtained in step S1 to the graphene is 3-5:1.

In some embodiments of the present invention, the homogenization method is ultrasonication for 3-6 hours.

Since the conductive material provided by the present invention has excellent electrical conductivity, and the porosity is also conducive to containing and passing active ions (lithium ions), the electrochemical performance of the obtained positive electrode sheet or negative electrode sheet can be improved.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and embodiment, wherein:

Fig. 1 is a scanning electron microscope image of the conductive material obtained in Example 1 of the present invention.

Detailed ways

The conception and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments, so as to fully understand the purpose, features and effects of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts belong to The protection scope of the present invention.

Example 1

In this embodiment, a conductive material is prepared, and the specific process is as follows:

A1. Collect soot particles from the exhaust gas emitted by diesel vehicles, and then calcinate these particles in an air atmosphere for 4 hours, and the calcining temperature is 200°C;

A2. Add 1g of zirconium nanoparticles into 100mL of ethanol, stir for 30min, then add 10g of soot particles obtained in step A1 and 1g of glucose, and keep at 80°C for 2h;

A3. The mixture obtained in the solid-liquid separation step A2, and the obtained solid was washed with acetone, and then the washed solid was dried at 50° C. for 6 h;

A4. Calcining the solid obtained in step A3 for 2 hours at 200° C. in an air atmosphere;

A5. Take 1g of graphene oxide and disperse it in 100mL of acetone, then add 3g of the solid obtained in step A4, ultrasonicate for 3h, and then dry until the solvent evaporates.

The morphology of the conductive material obtained in this embodiment is shown in FIG. 1 . It can be seen from the figure that the soot material is nearly spherical, and the obtained conductive material has a porous structure.

Example 2

In this embodiment, a conductive material is prepared, and the specific process is as follows:

A1. Collect soot particles from the exhaust gas emitted by diesel vehicles, and then calcinate these particles for 5 hours in an air atmosphere at a temperature of 220°C;

A2. Add 1.5g of zirconium nanoparticles into 100mL of ethanol, stir for 30min, then add 12g of soot particles obtained in step A1 and 1g of glucose, and maintain the reaction at 85°C for 2.5h;

A3. The mixture obtained in the solid-liquid separation step A2, and the obtained solid was washed with acetone, and then the washed solid was dried at 50° C. for 8 h;

A4. Calcining the solid obtained in step A3 for 2 hours at 200° C. in an air atmosphere;

A5. Take 1g of graphene oxide and disperse it in 100mL of acetone, then add 3.5g of the solid obtained in step A4, sonicate for 3h, and then dry until the solvent evaporates.

Example 3

In this embodiment, a conductive material is prepared, and the specific process is as follows:

A1. Collect soot particles from the exhaust gas emitted by diesel vehicles, and then calcinate these particles in an air atmosphere for 6 hours at a temperature of 240°C;

A2. Add 2g of zirconium nanoparticles into 100mL of ethanol, stir for 30min, then add 14g of soot particles obtained in step A1 and 1g of glucose, and keep at 90°C for 3h;

A3. The mixture obtained in the solid-liquid separation step A2, and the obtained solid was washed with acetone, and then the washed solid was dried at 50° C. for 9 h;

A4. Calcining the solid obtained in step A3 for 3 hours at 240° C. in an air atmosphere;

A5. Take 1g of graphene oxide and disperse it in 100mL of acetone, then add 4g of the solid obtained in step A4, ultrasonicate for 3h, and then dry until the solvent evaporates.

Example 4

In this embodiment, a conductive material is prepared, and the specific process is as follows:

A1. Collect soot particles from the exhaust gas emitted by diesel vehicles, and then calcinate these particles in an air atmosphere for 8 hours at a temperature of 300°C;

A2. Add 2g of zirconium nanoparticles into 100mL of ethanol, stir for 30min, then add 20g of soot particles obtained in step A1 and 1g of glucose, and keep at 100°C for 3h;

A3. The mixture obtained in the solid-liquid separation step A2, and the obtained solid was washed with acetone, and then the washed solid was dried at 50° C. for 12 h;

A4. Calcining the solid obtained in step A3 for 4 hours at 300° C. in an air atmosphere;

A5. Take 1g of graphene oxide and disperse it in 100mL of acetone, then add 5g of the solid obtained in step A4, ultrasonicate for 6h, and then dry until the solvent evaporates.

Comparative example 1

This comparative example has prepared a kind of conductive material, and the difference with embodiment 4 is:

(1) Steps A2-4 are not included;

(2) In step A5, the solid obtained in step A4 is replaced by the solid obtained in step A1;

That is, the formed conductive material is graphene oxide wrapped soot particles, and no zirconium nanoparticles are distributed in the pores or surfaces of the soot particles.

Comparative example 2

This embodiment prepares a kind of conductive material, and the difference with embodiment 4 is:

(1) Step A5 is not included.

That is, the material obtained in step A4 is directly used as a conductive material, specifically a composite material formed of zirconium nanoparticles and soot particles, but not wrapped by graphene oxide.

Test case

In this test example, the impedance of the conductive materials prepared in the examples and comparative examples and the conventional conductive material acetylene black was tested. Among them: the test method of specific surface area and porosity is BET, and the particle size is tested by a particle size analyzer.

The test results are shown in Table 1.

The performance of the conductive material obtained in table 1 embodiment 1～4 and comparative examples 1～2

Sample type	Impedance (Ω)	Particle size (nm)	Specific surface area (m 2 /g)	Porosity(%)
Example 1	43.5	31.5	482.6	65.4
Example 2	46.7	36.5	512.3	66.3
Example 3	42.4	34.2	496.4	63.5
Example 4	50.2	30.5	504.6	62.1
Comparative example 1	86.4	25.2	425.9	70.4
Comparative example 2	91.5	23.5	215.3	40.6
Comparative example 3 Acetylene black	65.6	34.4	346.3	52.6

The results in Table 1 show that the conductive agent provided by the present invention significantly reduces the impedance due to the synergistic effect of each component material and the positional relationship between them; after the lack of zirconium nanoparticles or graphene oxide in the conductive material, it will directly lead to a decrease in the impedance. rise (decrease in conductivity).

Compared with the conductive materials obtained in Examples 1-4 and Comparative Examples 1-2, the particle size, specific surface area and porosity are relatively similar, but the impedance of the conductive materials obtained in Examples 1-4 is significantly better than that obtained in Comparative Examples 1-2. conductive material. Finally, the performance of acetylene black, a commonly used conductive material, is obviously inferior to that of the conductive materials obtained in Examples 1-4. It shows that the present invention provides a synergistic effect between the structure and components of the conductive material, and finally improves the conductive performance.

In addition, the present invention adopts soot particles as porous carbon material, which belongs to the secondary utilization of solid waste, conforms to recycling economy, and has the advantages of low cost and simple preparation.

The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned embodiments, and within the scope of knowledge of those of ordinary skill in the art, various modifications can be made without departing from the spirit of the present invention. Variety. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other if there is no conflict.

Claims (10)

1. A conductive material, characterized in that it comprises:

   Porous carbon particles, zirconium nanoparticles are distributed in the pores and surfaces of the porous carbon particles;

   Graphene, the graphene wraps the porous carbon particles.
2. The conductive material according to claim 1, wherein the porous carbon particles are soot particles; preferably, the particle diameter of the conductive material is 30-40nm; preferably, the porosity of the conductive material is 60-70%.
3. The conductive material according to claim 1 or 2, characterized in that the mass ratio of the porous carbon particles to the zirconium nanoparticles is 5-10:1.
4. The conductive material according to claim 1 or 2, characterized in that the mass ratio of the sum of the mass of the porous carbon particles and the zirconium nanoparticles to the graphene is 3-5:1.
5. According to the preparation method of the conductive material described in any one of claims 1-4, it is characterized in that it comprises the following steps:

   S1. Adding the porous carbon particles to the dispersion of the zirconium nanoparticles, and calcining the obtained solid after the reaction;

   S2. The solid obtained in step S1 is wet-mixed with the graphene, and then the solvent is removed.
6. The preparation method according to claim 5, characterized in that, in step S1, the mass ratio of the porous carbon particles to the zirconium nanoparticles is 5-10:1.
7. The preparation method according to claim 5, characterized in that, in step S1, the reaction temperature is 80-100° C.; preferably, the reaction time is 2-4 hours.
8. The preparation method according to claim 5, characterized in that, in step S1, further comprising adding a binder to the dispersion of zirconium nanoparticles before the reaction.
9. The preparation method according to claim 8, wherein the binder comprises at least one of glucose and sucrose.
10. The preparation method according to claim 5, characterized in that, in step S1, the calcination temperature is 200-300° C.; preferably, the calcination time is 2-4 hours.

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