CN109111662B

CN109111662B - Preparation method of carbon material conductive film

Info

Publication number: CN109111662B
Application number: CN201710481555.6A
Authority: CN
Inventors: 胡敬平; 李玲; 侯慧杰; 楚鑫鹏; 武龙胜; 黎建峰; 刘冰川; 杨家宽; 朱小磊; 胡少刚; 汪东亮; 谢宗汉
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2017-06-22
Filing date: 2017-06-22
Publication date: 2020-07-10
Anticipated expiration: 2037-06-22
Also published as: CN109111662A

Abstract

The invention discloses a preparation method of a carbon material conductive film, which comprises the following steps: (1) mixing a plurality of carbon materials with conductivity, performing wet ball milling, and drying to prepare a mixed conductive carbon material; (2) mixing a conductive carbon material and a binder according to a mass ratio of 1-20: 1, grinding for 10-90 min, adding a dispersing agent, stirring for 10-120 min, and performing ultrasonic treatment for 30-120 min to obtain conductive homogenate; the conductive carbon material comprises a carbon aerogel; (3) and spin-coating the conductive homogenate liquid on the organic glass plate for 30-600 s at the rotating speed of 100-1000 r/min by adopting a spin-coating method, and drying to obtain the conductive film. The preparation method of the carbon material conductive film solves the problems of agglomeration of the traditional conductive homogenate liquid spin coating film preparation and poor cohesiveness of an organic glass plate and the homogenate liquid, and the prepared film shows good conductive performance and has good application prospect.

Description

Preparation method of carbon material conductive film

Technical Field

The invention belongs to the field of preparation of conductive carbon material films, and particularly relates to a preparation method of a carbon material conductive film.

Background

Spin coating is also called homogenization because the fluid used is viscous and colloidal. The spin coating process includes three steps of material compounding, rotation and drying, and the thickness of the formed film is controlled through controlling the glue homogenizing time, rotation speed, dripping amount, concentration and viscosity of the solution. Compared with the film preparation technologies such as an electrochemical method, a physical/chemical vapor deposition method and the like, the spin coating method has the unique advantages of mild process conditions, simplicity in operation and control and the like, so that the effects of reducing pollution, saving energy, improving cost performance and the like are remarkable, in recent years, the spin coating method is continuously emphasized, and the application of the spin coating method is gradually popularized to the fields of physics, medicine, biology and the like.

The key step in the spin coating method is to prepare a homogenate, and the concentration and the viscosity of the homogenate have great influence on the thickness and the performance of the film. The carbon material conductive film is a preferential material for manufacturing the film due to the advantages of good conductivity, easy operation, low cost and the like, the spin coating method is a preferred technology for preparing the film due to the advantages of simple operation and easy control of process conditions, however, the carbon particles are easy to generate agglomeration phenomenon in the process of preparing the conductive carbon material film by using the traditional spin coating method, and the film is easy to crack in the process of drying the film.

Disclosure of Invention

In view of the above defects or improvement needs of the prior art, the present invention provides a method for preparing a carbon material conductive film, which aims to solve the technical problems of agglomeration during the preparation process of the carbon material conductive film and film cracking during the drying process in the prior art by preparing a conductive homogenate by using a carbon material containing carbon aerogel, spin-coating a layer of conductive film on an organic glass plate by using a homogenizer, and controlling the preparation process parameters and the drying treatment process.

In order to achieve the above object, according to one aspect of the present invention, there is provided a method for preparing a carbon material conductive film, comprising the steps of:

(1) mixing a conductive carbon material and a binder according to a mass ratio of 1-20: 1, grinding for 10-90 min, adding a dispersing agent, stirring for 10-120 min, and performing ultrasonic treatment for 30-120 min to obtain conductive homogenate; the conductive carbon material comprises a carbon aerogel;

(2) and (2) spin-coating the conductive homogenate obtained in the step (1) on an organic glass plate for 30-600 s at the rotating speed of 100-1000 r/min by adopting a spin-coating method, and drying to obtain the conductive film.

Preferably, the carbon material of step (1) further comprises one or more of conductive graphite powder, acetylene black and activated carbon.

Preferably, the preparation method of the carbon material in the step (1) is as follows: adding a solvent into a mixture of the carbon aerogel and one or more of the conductive graphite powder, the acetylene black and the activated carbon, and then carrying out wet ball milling in a ball mill.

Preferably, the solvent is one or more of deionized water, ethanol, isopropanol and ethylene glycol.

Preferably, the rotation speed of the wet ball milling is 100-800 r/min, and the ball milling time is 5-24 h.

Preferably, the binder in step (1) is one or more of acrylic latex, polyvinyl ketone, polyvinylidene fluoride, phenolic resin and epoxy resin.

Preferably, the mass ratio of the carbon material to the binder in the step (1) is 4-12: 1.

Preferably, the dispersant in step (1) is one or more of fatty acid, polysiloxane, 1-methyl-2 pyrrolidone, polyvinylpyrrolidone and sodium lauryl sulfate.

Preferably, the stirring time in the step (1) is 10-60 min, and the ultrasonic time is 30-60 min.

Preferably, the organic glass plate in the step (2) is an ultrasonically treated and dried organic glass plate.

Preferably, the ultrasonic time is 20-120 min.

Preferably, the rotating speed in the step (2) is 100-500 r/min, and the spin coating time is 30-200 s.

Preferably, the drying condition in the step (2) is that the temperature is within the range of 30-50 ℃, and the airflow disturbance speed is within the range of 0.1-0.8 m/s.

Preferably, the drying is carried out in a vacuum drying oven with the temperature of 30-45 ℃ or under the irradiation of an infrared lamp with the airflow disturbance speed of 0.1-0.15 m/s.

In general, the above technical solutions contemplated by the present invention can achieve the following advantageous effects compared to the prior art.

(1) According to the invention, when the carbon material conductive film is prepared, the carbon aerogel is added into the initial carbon material, and the carbon aerogel is a light, porous and amorphous nano carbon material, and a continuous three-dimensional network structure of the carbon aerogel can be controlled and cut in a nano scale, so that the problem of agglomeration generated when the conductive homogenate liquid is spin-coated can be well solved;

(2) the conductive graphite powder and the carbon aerogel are mixed to be used as the conductive carbon material, so that the conductivity of the prepared carbon material conductive film can be greatly increased;

(3) the temperature and the airflow disturbance speed are accurately controlled in the drying process, so that the viscosity between the conductive carbon material film and the substrate can be increased in the drying process, and the cracking phenomenon of the conductive carbon material film in the traditional drying process can be effectively avoided.

(4) The preparation of the carbon material conductive film adopts organic glass as a substrate, and the organic glass plate has high mechanical strength and good processability, so that the conductive film prepared on the organic glass base is convenient to process and easy to carve in subsequent application.

(5) The preparation method of the carbon material conductive film forms an inseparable integral technical scheme by optimizing and controlling each step and parameters and mutually cooperating, the finally prepared carbon material conductive film has good conductivity, no particle agglomeration problem in the spin coating process, and no film dry cracking phenomenon in the drying process.

Drawings

FIG. 1 is a Scanning Electron Microscope (SEM) image of a carbon aerogel carbon material for use in the present invention;

FIG. 2 is a diagram showing an embodiment of the conductive film before drying, which is obtained in comparative example 1;

FIG. 3 is a schematic representation of the dried film obtained in comparative example 2;

FIG. 4(a) is a diagram showing a real object of the conductive film after the conductive film prepared in example 1 is dried in a natural condition; (b) a real image of the conductive film obtained after the conductive film prepared in example 1 was dried in an air drying oven at 45 ℃; (c) a real image of the conductive film obtained after the conductive film prepared in example 1 was dried in a vacuum oven at 45 ℃; (d) is a real image of the conductive film after the conductive film prepared in example 1 is irradiated and dried by a 100W infrared lamp.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The preparation method of the carbon material conductive film provided by the invention comprises the following steps:

(1) uniformly mixing a conductive carbon material and a binder according to the mass ratio of 1-20: 1, preferably 4-12: 1, grinding for 10-90 min, adding a dispersing agent, stirring for 10-120 min, and performing ultrasound for 30-120 min to fully mix, wherein the preferable stirring time is 10-60 min, and the ultrasound time is 30-60 min to obtain conductive homogenate, and in addition, the stirring ultrasound time is not too long, so that moisture absorption and agglomeration of the homogenate are avoided; the conductive carbon material comprises carbon aerogel; the carbon aerogel has a continuous three-dimensional network structure, so that the disordered porous network structure can be still maintained even under the condition of grinding and crushing, and the effect of chemical bonds among particles can be further weakened to effectively prevent the agglomeration among the particles; the carbon material may further include one or more of conductive graphite powder, acetylene black, and activated carbon, which may increase the conductivity of the resulting conductive film.

One of the preparation methods of the conductive carbon material is as follows: adding a solvent into a mixture of carbon aerogel and one or more of conductive graphite powder, acetylene black and active carbon, and then carrying out wet ball milling in a ball mill to uniformly mix the mixed carbon materials; the solvent is one or more of deionized water, ethanol, isopropanol and ethylene glycol; the rotation speed of the wet ball milling is preferably 100-800 r/min, and the ball milling time is preferably 5-24 h. The conductive carbon material prepared by wet ball milling enables various carbon materials to be fully mixed, the carbon materials can be effectively ground into nano particles, and the smaller the particle size is, the more uniform the prepared homogenate is.

One preparation method of the carbon aerogel is a formaldehyde-resorcinol method, wherein resorcinol, formaldehyde, deionized water and sodium carbonate are mixed and stirred until the mixture is clear, and the molar ratio is 1:2:17.5: 0.0008. Transfer to a container, seal to prevent moisture evaporation, heat cure in an oven: curing at 30 ℃ for one day, 50 ℃ for one day and 90 ℃ for three days. The prepared wet gel was then placed in acetone solution and soaked for three days with the acetone changed once a day. Then dried at room temperature for four more days. And finally, roasting the dried gel in a tubular furnace to obtain carbon aerogel, heating to 950 ℃ at the heating rate of 2.5 ℃/min under the protection of nitrogen, maintaining at 950 ℃ for 4 hours, and cooling to room temperature.

The binder is one or more of acrylic latex, polyvinyl ketone, polyvinylidene fluoride, phenolic resin and epoxy resin; the dispersant is one or more of fatty acid, polysiloxane, 1-methyl-2 pyrrolidone, polyvinylpyrrolidone and sodium dodecyl sulfate.

(2) And (2) spin-coating the conductive homogenate liquid obtained in the step (1) on the organic glass plate for 30-600 s at the rotation speed of 100-1000 r/min, performing spin-coating in a homogenizer at the rotation speed of 100-500 r/min preferably for 30-200 s, and drying to obtain the conductive film.

The organic glass plate is subjected to ultrasonic treatment and drying, the ultrasonic time is preferably 20-120 min, and the purpose and effect of ultrasonic treatment of the organic glass plate are to remove dry glue for packaging the organic glass plate, stains on the dry glue and the like.

The drying condition is controlled to be that the organic glass plate coated with the conductive homogenate liquid in a spinning mode is dried under the conditions that the temperature is 30-50 ℃ and the airflow disturbance speed is 0.1-0.8 m/s; the purpose and the function of controlling the drying condition are to avoid the deformation of the organic glass plate caused by overhigh temperature, and the cracking of the conductive carbon material film in the drying process caused by overhigh airflow disturbance speed and high temperature. Preferably, the drying is carried out in a vacuum drying oven at a temperature of 30 to 45 ℃ or under irradiation of an infrared lamp at an air flow disturbance speed of 0.1 to 0.15 m/s. The film that natural drying or forced air drying made under the condition all can all appear the problem more or less, because lack of heating condition makes the cohesiveness between film and the organic glass board poor under the natural drying condition, and the air current disturbance is great under the forced air drying condition makes the film fracture in drying process, compares former two, and infrared lamp irradiation temperature is between 30 ~ 45 ℃, and the air current disturbance is less under the indoor condition consequently has good effect in film drying process.

The following are examples:

comparative example 1

(1) Mixing conductive graphite powder, activated carbon and acetylene black according to the mass ratio of 3:2:1, adding isopropanol, putting the mixture into a ball mill, carrying out ball milling for 10 hours at the ball milling speed of 500r/min, and drying ball-milling mixed slurry to prepare a conductive carbon material;

(2) mixing and grinding the conductive carbon material prepared in the step (1) and polyvinylidene fluoride serving as a binder for 30min according to a mass ratio of 8: 1;

(3) adding a dispersing agent 1-methyl-2-pyrrolidone into the mixed material obtained in the step (2), stirring for 30min, and carrying out ultrasonic treatment for 60min to obtain a homogenate;

(4) cleaning the organic glass plate for 30min by using an ultrasonic cleaner, drying, then placing on a refiner, dripping the refiner prepared in the step (3), setting the rotating speed of the refiner to be 300r/min, and setting the time to be 120s, thus preparing the film; FIG. 1 is a physical representation of the resulting film, and it can be seen from FIG. 1 that agglomeration of carbon material particles in the homogenate has occurred.

(5) The organic glass plate coated with the conductive film was dried in a vacuum oven at 40 ℃.

Comparative example 2

(1) Mixing and grinding conductive graphite powder and a binding agent polyvinylidene fluoride for 40min according to a mass ratio of 6: 1;

(2) adding the mixed material obtained in the step (1) into a dispersing agent 1-methyl-2-pyrrolidone, stirring for 10min, and performing ultrasonic treatment for 40min to obtain a homogenate;

(3) cleaning the organic glass plate for 20min by using an ultrasonic cleaning instrument, drying, placing on a refiner, dripping the refiner prepared in the step (2), setting the rotating speed of the refiner to be 200r/min, and setting the time to be 180s to prepare a film;

(4) and (3) placing the organic glass plate coated with the conductive film under a 100W infrared lamp with the airflow disturbance speed of 0.1m/s for irradiation and drying.

FIG. 2 is a diagram of a dried film prepared in comparative example 2, in which the conductivity of the conductive graphite powder is good, but agglomeration (accumulation and "bulging" of particles) is still not avoided; meanwhile, as the film is finally irradiated and dried under a 100W infrared lamp, although particle agglomeration occurs in the film, the cracking phenomenon does not occur.

Example 1

(1) The preparation of the carbon aerogel material adopts a formaldehyde-resorcinol method, and the prepared carbon aerogel material is ground for later use; mixing resorcinol, formaldehyde, deionized water and sodium carbonate, and stirring until the mixture is clear, wherein the molar ratio is 1:2:17.5: 0.0008. Transferring to a container, sealing to prevent moisture evaporation, heating in an oven for curing, curing at 30 ℃ for one day, 50 ℃ for one day, and 90 ℃ for three days. The prepared wet gel was then placed in acetone solution and soaked for three days with the acetone changed once a day. Then dried at room temperature for four more days. And finally, roasting the dried gel in a tubular furnace to obtain carbon aerogel, heating to 950 ℃ at the heating rate of 2.5 ℃/min under the protection of nitrogen, maintaining at 950 ℃ for 4 hours, and then cooling to room temperature.

Fig. 1 is an SEM image of the carbon aerogel carbon material prepared, and it can be seen that the carbon aerogel material is composed of fine nano particles, and the porosity between the particles is large.

(2) Mixing and grinding the conductive carbon material prepared in the step (1) and polyvinylidene fluoride serving as a binder for 15min according to a mass ratio of 4: 1;

(3) adding a dispersing agent 1-methyl-2-pyrrolidone into the mixed material obtained in the step (2), stirring for 15min, and performing ultrasonic treatment for 30min to obtain homogenate;

(4) cleaning the organic glass plate for 30min by using an ultrasonic cleaner, drying, then placing on a refiner, dripping the refiner prepared in the step (3), setting the rotating speed of the refiner to be 300r/min, and setting the time to be 120s, thus preparing the film;

(5) the organic glass plate coated with the conductive film is respectively placed in a ventilated place, a vacuum drying oven at 45 ℃, an air blast drying oven at 45 ℃ and a 100W infrared lamp with the air flow disturbance speed of 0.1m/s for drying, and the resistance value is measured by a universal meter along the diagonal point of the organic glass plate (5cm × 5cm) and is about 800 omega.

Fig. 4 is a diagram of the conductive film prepared in example 1 after being dried in a natural condition (a), a 45 ℃ forced air drying oven (b), a 45 ℃ vacuum drying oven (c) and a 100W infrared lamp (d), respectively, in which the adhesion between the film and the organic glass plate is poor when the film is dried in the natural condition in fig. 4(a), the dried film is easily peeled off, which is shown in the left side of fig. 4 (a); fig. 4(b) shows the situation that the film dried in the forced air drying oven has cracks, fig. 4(c) and fig. 4(d) show better effect of the film dried in the vacuum drying oven and by infrared lamp irradiation respectively, and the infrared lamp irradiation operation is simpler and the drying time is shorter, thus being a better choice of the drying mode. In addition, as can be seen from the four pictures in fig. 4, the carbon aerogel is adopted in the carbon material, so that the prepared film is flat and compact, and has no agglomeration phenomenon.

Example 2

(1) The carbon aerogel material is prepared by adopting a formaldehyde-resorcinol method (the specific preparation method is the same as that in example 1), the prepared carbon aerogel material is ground, the carbon aerogel and conductive graphite powder are mixed according to the mass ratio of 4:1, isopropanol is added, the mixture is put into a ball mill for ball milling for 10 hours, the ball milling speed is set to be 300r/min, and the ball milling mixed slurry is dried to prepare the conductive carbon material.

(2) Mixing and grinding the mixed carbon material prepared in the step (1) and polyvinylidene fluoride serving as a binder for 30min according to a mass ratio of 4: 1;

(3) adding a dispersing agent 1-methyl-2-pyrrolidone into the mixed material obtained in the step (2), stirring for 10min, and performing ultrasonic treatment for 40min to obtain homogenate;

(4) placing the organic glass plate on a homogenizer, dripping the homogenate liquid prepared in the step (3), setting the rotating speed of the homogenizer to be 200r/min, and setting the time to be 200s to prepare a film;

(5) the organic glass plate coated with the conductive film is respectively placed in a vacuum drying oven at 30 ℃ and a 100W infrared lamp with the airflow disturbance speed of 0.15m/s for drying, and the uniform, compact, agglomeration-free and cracking-free conductive film of the carbon material with good conductivity can be obtained, the conductivity of the conductive film is improved to a certain extent, and the resistance value is about 200 omega when the conductive film is measured along the diagonal point of the organic glass plate (5cm × 5 cm).

Example 3

(1) Mixing the prepared carbon aerogel with graphite powder according to the mass ratio of 6:1, adding isopropanol, putting the mixture into a ball mill, carrying out ball milling for 10 hours at the ball milling speed of 300r/min, and drying the ball-milled mixed slurry to prepare the conductive carbon material.

(2) Mixing and grinding the mixed carbon material prepared in the step (1) and polyvinylidene fluoride serving as a binder for 30min according to the mass ratio of 6: 1;

(3) adding a dispersing agent 1-methyl-2-pyrrolidone into the mixed material obtained in the step (2), stirring for 20min, and performing ultrasonic treatment for 30min to obtain homogenate;

(4) placing the organic glass plate on a homogenizer, dripping the homogenate liquid prepared in the step (3), setting the rotating speed of the homogenizer to be 300r/min, and setting the time to be 60s to prepare a film;

(5) the organic glass plate coated with the conductive film is respectively placed under a vacuum drying oven at 50 ℃ and a 100W infrared lamp with the air flow disturbance speed of 0.1m/s for drying, and the uniform, compact, agglomeration-free and cracking-free conductive film of the carbon material with good conductivity can be obtained.

Example 4

(1) Mixing the prepared carbon aerogel with graphite powder in a mass ratio of 8:1, adding isopropanol, putting the mixture into a ball mill, carrying out ball milling for 8 hours at a ball milling speed of 500r/min, and drying the ball-milled mixed slurry to prepare the conductive carbon material.

(2) Mixing and grinding the mixed carbon material prepared in the step (1) and polyvinylidene fluoride serving as a binder for 30min according to a mass ratio of 9: 1;

(3) adding a dispersing agent 1-methyl-2-pyrrolidone into the mixed material obtained in the step (2), stirring for 40min, and performing ultrasonic treatment for 60min to obtain homogenate;

(4) placing the organic glass plate on a homogenizer, dripping the homogenate liquid prepared in the step (3), setting the rotating speed of the homogenizer to be 400r/min, and setting the time to be 30s to prepare a film;

(5) the organic glass plate coated with the conductive film is respectively placed under a vacuum drying oven at 40 ℃ and a 100W infrared lamp with the air flow disturbance speed of 0.1m/s for drying, and the uniform, compact, agglomeration-free and cracking-free conductive film of the carbon material with good conductivity can be obtained.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A preparation method of a carbon material conductive film is characterized by comprising the following steps:

(1) mixing a conductive carbon material and a binder according to a mass ratio of 1-20: 1, grinding for 10-90 min, adding a dispersing agent, stirring for 10-120 min, and performing ultrasonic treatment for 30-120 min to obtain conductive homogenate; the conductive carbon material comprises carbon aerogel and one or more of conductive graphite powder, acetylene black and active carbon; the preparation method of the conductive carbon material comprises the following steps: adding a solvent into a mixture of one or more of the conductive graphite powder, the acetylene black and the activated carbon and the carbon aerogel, and then carrying out wet ball milling in a ball mill; the mass ratio of the conductive carbon material to the binder is 4-12: 1; the binder is one or more of acrylic latex, polyvinylidene fluoride, phenolic resin and epoxy resin;

(2) spin-coating the conductive homogenate obtained in the step (1) on an organic glass plate for 30-600 s at a rotating speed of 100-1000 r/min by adopting a spin-coating method, and drying to obtain a conductive film; the drying condition is that the temperature is within the range of 30-50 ℃, and the air flow disturbance speed is within the range of 0.1-0.8 m/s.

2. The method of claim 1, wherein the solvent is one or more of deionized water, ethanol, isopropanol, and ethylene glycol; the rotation speed of the wet ball milling is 100-800 r/min, and the ball milling time is 5-24 h.

3. The method of claim 1, wherein the dispersant of step (1) is one or more of fatty acid, polysiloxane, 1-methyl-2 pyrrolidone, polyvinylpyrrolidone, and sodium lauryl sulfate.

4. The preparation method according to claim 1, wherein the stirring time in the step (1) is 10 to 60min, and the ultrasonic time is 30 to 60 min.

5. The preparation method of claim 1, wherein the organic glass plate in the step (2) is an ultrasonically treated and dried organic glass plate, and the ultrasonic time is 20-120 min.

6. The method according to claim 1, wherein the rotation speed in the step (2) is 100 to 500r/min, and the spin coating time is 30 to 200 s.

7. The method according to claim 1, wherein the drying in step (2) is performed in a vacuum drying oven at a temperature of 30 to 45 ℃ or under irradiation of an infrared lamp at a gas flow disturbance speed of 0.1 to 0.15 m/s.