Graphene nanosheet material, and rapid manufacturing method and application thereof
阅读说明：本技术 石墨烯纳米片材料、其快速制造方法及应用 (Graphene nanosheet material, and rapid manufacturing method and application thereof ) 是由 郝奕舟 吴永生 陈剑豪 王天戌 于 2019-09-06 设计创作，主要内容包括：石墨烯纳米片材料、其快速制造方法及应用,该方法包括：采用等离子体增强化学气相沉积(PECVD)方法,以含碳气体和辅助气体的混和气体作为碳源,快速制备石墨烯纳米片材料。基于该石墨烯纳米片材料,制备复合导电浆料,包括石墨烯纳米片材料,导电高分子,分散剂、稳定剂和溶剂组成。(Graphene nanoplatelets, a rapid manufacturing method and applications thereof, the method comprising: and rapidly preparing the graphene nanosheet material by using a Plasma Enhanced Chemical Vapor Deposition (PECVD) method and using a mixed gas of a carbon-containing gas and an auxiliary gas as a carbon source. The composite conductive slurry is prepared based on the graphene nanosheet material and comprises the graphene nanosheet material, a conductive polymer, a dispersing agent, a stabilizing agent and a solvent.)
1. A graphene nanosheet material and a rapid manufacturing method thereof include: and (3) rapidly preparing the graphene nanosheet material by adopting a Plasma Enhanced Chemical Vapor Deposition (PECVD) method and taking a mixed gas of a carbon-containing gas and an auxiliary gas as a reaction gas source.
2. The method according to claim 1, wherein a magnetic field perpendicular to the gas flow is applied to the plasma during the growth of the graphene nanoplatelet material, and the magnetic field strength is 1-10 μ T; preferably 3. mu.T to 6. mu.T.
3. The method according to claim 1 or 2, characterized in that during the growth of the graphene nanoplatelet material, a voltage of-5V to-20V with respect to plasma is applied on the substrate; preferably, a voltage of-10V to-15V with respect to the plasma is applied to the substrate.
4. The method according to any one of claims 1 to 3, wherein the growth temperature for growing the graphene nanosheet material on the functional substrate is 750-1100 ℃, preferably 850-950 ℃;
preferably, the volume ratio of the carbon-containing gas to the auxiliary gas is 1: 10-1: 100, and the auxiliary gas comprises argon, nitrogen and hydrogen;
preferably, the volume ratio of the argon gas, the nitrogen gas and the hydrogen gas in the auxiliary gas is 10:1
Preferably, the carbon-containing gas comprises CH4、C2H4，C2H2、C2F6。
5. A graphene nanoplatelet manufactured according to the method of any of claims 1-4, wherein the graphene nanoplatelet has a specific surface area of 300m2/g～900m2/g。
6. The graphene nanosheet material of claim 5, wherein the single graphene nanosheets are approximately petal-shaped, straight, or have a curvature and are partially curled, including flat, wrinkled, curved, and wavy.
7. Graphene nanoplatelets according to claim 5 wherein the graphene nanoplatelets of the graphene nanoplatelets have a graphene nanoplatelet size of 10nm to 50nm, preferably 15nm to 30 nm;
preferably, the thickness of the nanosheet in the graphene nanosheet material is 0.33nm to 3.5nm, preferably 0.9nm to 2.6 nm;
preferably, the graphene nanosheet material is porous, and the pore size is 5nm to 100nm, preferably 10nm to 30 nm;
preferably, the graphene nanosheet material is porous in the inside and has a porosity of 3cm3/g～5cm3G, preferably 3.5cm3/g～4.5cm3/g；
Preferably, the density of the graphene nanosheet material is 0.2g/cm3～0.6g/cm3Preferably 0.3g/cm3～0.5g/cm3；
Preferably, the graphene nanosheet material comprises particles composed of the graphene nanosheets, the particle size is 500 nm-1500 nm, preferably 800 nm-1100 nm, and the particles are irregular in shape;
preferably, a bifurcation structure is formed among the multiple graphene nanosheets; a small part of the overlapping between the sheets is not more than 30%;
preferably, the graphene nanoplatelets have the morphology shown in fig. 2.
8. The graphene nanoplatelet material of claim 7 wherein the graphene nanoplatelets particles have an SEM image as shown in figure 1.
9. The composite conductive paste is characterized by comprising the graphene nanosheet material as defined in any one of claims 5 to 8, a conductive polymer, a dispersant, a stabilizer and a solvent, wherein the viscosity of the graphene nanosheet material composite conductive paste is 8000-50000mPa.s, preferably 10000-25000mPa.s, preferably 15000-20000 mPa.s.
10. The composite conductive paste according to claim 9, characterized in that the fineness of the composite conductive paste is 5-50 microns, preferably 7-20 microns, preferably 10-15 microns.
11. The composite conductive paste as claimed in claim 9, wherein the conductivity of the composite conductive paste is 300-1000S/m, preferably 400-900S/m, preferably 500-800S/m.
12. The composite conductive paste according to claim 9, wherein the graphene nanoplatelets comprise graphene nanoplatelet particles and graphene nanoplatelets.
13. The composite conductive paste as claimed in claim 12, wherein the powder conductivity of the graphene nanoplatelets particles is greater than 104S.m-1。
14. The composite conductive paste according to claim 9, wherein the conductive polymer is at least one of polyaniline, polythiophene and polypyrrole, and the mass of the conductive polymer accounts for 1-2% of the total mass of the paste.
15. The composite conductive paste according to claim 9, wherein the dispersant is at least one of polyvinylpyrrolidone, polyacrylamide, and sodium dodecylbenzenesulfonate; the mass of the dispersant accounts for 0.1-0.2 per mill of the total mass of the slurry.
16. The composite conductive paste according to claim 9, wherein the stabilizer is at least one of polyvinylidene fluoride, sodium carboxymethylcellulose, resin and polyacrylic acid, and the mass of the stabilizer accounts for 0.05-0.15% of the total mass of the paste.
17. The composite conductive paste according to claim 9, wherein the solvent is one of water, N-methyl pyrrolidone, and alcohol.
18. The composite conductive paste according to claim 9, wherein the graphene particles in the graphene nanoplatelet composite conductive paste account for 1-10%, preferably 2-8%, and preferably 3-7% of the total mass of the paste by mass.
Technical Field
The present disclosure relates to graphene nanoplatelets, rapid manufacturing methods and applications thereof.
Background
Graphene (Graphene) is a two-dimensional crystal composed of 1-10 layers of carbon atoms. In 2004, the physicists andrelim and consanguin norworth schloff, manchester university, uk, succeeded in separating graphene from graphite, confirming that it can exist alone, and thus both people together won the 2010 nobel prize for physics.
At present, graphene has very promising application in many aspects, but has many technical problems to be solved in the practical process.
Disclosure of Invention
The embodiment of the invention provides a graphene nanosheet material and a rapid manufacturing method thereof, and the method comprises the following steps: and (3) rapidly preparing the graphene nanosheet material by adopting a Plasma Enhanced Chemical Vapor Deposition (PECVD) method and taking a mixed gas of a carbon-containing gas and an auxiliary gas as a reaction gas source.
According to an embodiment of the invention, in the growth process of the graphene nano sheet material, a magnetic field perpendicular to the air flow is applied to the plasma, and the magnetic field strength is 1-10 μ T; preferably 3. mu.T to 6. mu.T.
According to one embodiment of the invention, during the growth of the graphene nano sheet material, a voltage of-5V to-20V relative to plasma is applied to the substrate; preferably, a voltage of-10V to-15V with respect to the plasma is applied to the substrate.
According to an embodiment of the invention, the growth temperature range of the graphene nanosheet material grown on the functional substrate is 750-1100 ℃, preferably 850-950 ℃;
preferably, the volume ratio of the carbon-containing gas to the auxiliary gas is 1: 10-1: 100, and the auxiliary gas comprises argon, nitrogen and hydrogen.
Preferably, the volume ratio of the argon gas, the nitrogen gas and the hydrogen gas in the auxiliary gas is 10:1: 1.
Preferably, the carbon-containing gas comprises CH4、C2H4，C2H2、C2F6。
Embodiments of the present invention provide a graphite manufactured according to the aforementioned methodThe graphene nanosheet material has a specific surface area of 300m2/g～900m2(ii) in terms of/g. In accordance with one embodiment of the present invention,
the shape of the single graphene nanosheet is close to that of a petal, or is straight, or has a certain radian and is partially curled, and the shape comprises a flat shape, a wrinkled shape, an arc shape and a wave shape.
According to an embodiment of the present invention, the graphene nanoplatelets of the graphene nanoplatelet material have a size of 10nm to 50nm, preferably 15nm to 30 nm;
preferably, the thickness of the nanosheet in the graphene nanosheet material is 0.33nm to 3.5nm, preferably 0.9nm to 2.6 nm;
preferably, the graphene nanosheet material is porous, and the pore size is 5nm to 100nm, preferably 10nm to 30 nm;
preferably, the graphene nanosheet material is porous in the inside and has a porosity of 3cm3/g～5cm3G, preferably 3.5cm3/g～4.5cm3/g；
Preferably, the density of the graphene nanosheet material is 0.2g/cm3～0.6g/cm3Preferably 0.3g/cm3～0.5g/cm3；
Preferably, the graphene nanosheet material comprises particles composed of the graphene nanosheets, the particle size is 500 nm-1500 nm, preferably 800 nm-1100 nm, and the particles are irregular in shape.
Preferably, a bifurcation structure is formed among the multiple graphene nanosheets; a small part of the overlapping between the sheets is not more than 30%;
preferably, the graphene nanoplatelets have the morphology shown in fig. 2.
According to an embodiment of the invention, the graphene nanoplatelets particles have an SEM image as shown in fig. 1.
The embodiment of the invention provides a composite conductive paste, which comprises the graphene nanosheet material, a conductive polymer, a dispersant, a stabilizer and a solvent, wherein the viscosity of the graphene nanosheet material composite conductive paste is 8000-50000mPa.s, preferably 10000-25000mPa.s, and preferably 15000-20000 mPa.s.
According to one embodiment of the invention, the fineness of the composite conductive paste is 5-50 microns, preferably 7-20 microns, and preferably 10-15 microns.
According to an embodiment of the invention, the conductivity of the composite conductive paste is 300-1000S/m, preferably 400-900S/m, and preferably 500-800S/m.
According to an embodiment of the present invention, the graphene nanoplatelets material includes graphene nanoplatelets particles and graphene nanoplatelets.
According to an embodiment of the present invention, the graphene nanoplatelet particle powder has an electrical conductivity of more than 104S.m-1。
According to an embodiment of the present invention, the conductive polymer is at least one of polyaniline, polythiophene, and polypyrrole, and the mass of the conductive polymer accounts for 1 to 2% of the total mass of the slurry.
According to one embodiment of the invention, the dispersant is at least one of polyvinylpyrrolidone, polyacrylamide and sodium dodecyl benzene sulfonate; the mass of the dispersant accounts for 0.1-0.2 per mill of the total mass of the slurry.
According to one embodiment of the invention, the stabilizer is at least one of polyvinylidene fluoride, sodium carboxymethylcellulose, resin and polyacrylic acid, and the mass of the stabilizer accounts for 0.05-0.15 per mill of the total mass of the slurry.
According to an embodiment of the present invention, the solvent is one of water, N-methylpyrrolidone, and alcohol.
According to an embodiment of the invention, the graphene particles in the graphene nano sheet material composite conductive paste account for 1-10%, preferably 2-8%, and preferably 3-7% of the total mass of the paste.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly described below, and it is apparent that the drawings in the following description only relate to some embodiments of the present invention and are not limiting on the present invention.
Fig. 1 is a SEM image of a front side (i.e., a direction perpendicular to a substrate, or a thickness direction of a graphene nanoplatelet material) of a graphene nanoplatelet material provided in example 4 of the present invention;
fig. 2 is a transmission electron microscope photograph of graphene nanoplatelets provided in embodiment 4 of the present invention;
fig. 3 is a charge and discharge curve of a battery prepared from the graphene composite conductive paste prepared in example 1 at different rates;
FIG. 4 is a charge-discharge curve of a battery prepared by using Super P as a conductive agent under different multiplying powers;
fig. 5 is a charge-discharge curve of a battery prepared by using common graphene as a conductive agent under different multiplying factors.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The rapid growth of high-quality graphene has always been a technical bottleneck that restricts large-scale commercial application of graphene. Although the preparation of graphene by the PECVD method has been 10 years old, the production cost of the method is high due to the defects of low speed, low yield and the like of the graphene, and is far higher than the cost of other methods such as a chemical oxidation method, a physical method and the like. However, the quality of the graphene prepared by the PECVD method is obviously superior to that of the graphene obtained by other methods, and the realization of large-scale preparation of the three-dimensional graphene by the PECVD method is always a hot spot in the field of graphene research. Other researchers in the field have tried various methods to increase the growth rate of graphene, such as increasing the amount of reactants, increasing the reaction temperature, changing the reaction formula, and the like. However, the growth rate is increased only in a limited way, and the quality of graphene is often seriously reduced, and graphene cannot be obtained even, but a large amount of amorphous carbon is obtained. In addition, for the three-dimensional graphene nanosheet with the nano-porous structure, the growth rate is greatly increased, the high quality is ensured, and meanwhile, the nano-porous structure of the three-dimensional graphene needs to be maintained unchanged, which is more difficult to add and has not been broken through for many years. According to the invention, a fully improved PECVD method is used, and through optimization promotion in multiple aspects, a graphene material which can grow at a very high speed and keeps a three-dimensional structure is obtained, and the material has a fine nano-porous structure and high-quality graphene nanosheets, so that the problem of a large difficulty in the field of three-dimensional graphene research is solved.
The conductive agent is used as an indispensable material in the lithium ion battery, and plays a significant role in improving the conductivity of the material, constructing a conductive network, providing a rapid channel for electron transmission and ensuring that active substances are fully utilized. At present, point contact exists between the commercial carbon black and the active substance, and the point contact exists between the carbon nano tubes, so that a complete conductive network structure is not formed. The graphene has excellent conductivity and has great advantages in constructing a large-area conductive network. The contact mode of the graphene is point-to-surface contact, the surfaces of active materials can be connected to form a large-area conductive network as a main body, but because the graphene only conducts electrons and does not conduct ions, the migration of lithium ions is hindered by the large-sheet two-dimensional graphene in the practical application process. Although the problem of lithium ion migration resistance can be solved to a certain extent by reducing the size of the two-dimensional graphene particles, the two-dimensional graphene particles with small particle size are more prone to agglomeration in the actual application process due to the pi-pi conjugation effect, and in addition, a good conductive network can be formed in the electrode only by adding more graphene particles after the graphene particle size is reduced. According to the invention, by utilizing the characteristics that three-dimensional graphene is not easy to agglomerate, holes are enriched to provide channels for lithium ion migration, and conductive polymers are used as flexible bridges for connecting graphene particles, the graphene is prepared into the high-dispersion-state graphene composite slurry by using a three-dimensional graphene and conductive polymer composite technology, and the technology not only solves the problem that small-particle-size graphene is easy to agglomerate, but also solves the problems of lithium ion diffusion and conductive network integrity during use.
As described above, the present inventors have adopted that the present invention has at least the following advantages:
1) the embodiment of the invention provides a graphene nanosheet material capable of being rapidly grown, and compared with the conventional PECVD method, the production rate of the graphene nanosheet material is increased by several times to several tens of times.
2) The high-speed growth is realized, and simultaneously, the obtained graphene nanosheet is maintained at a high quality.
3) The obtained material has a fine three-dimensional mesoporous structure while realizing high-speed growth.
4) The method of the invention is simple and easy to operate, and can be applied to large-scale industrial production.
5) The invention provides a composite conductive slurry based on a graphene nanosheet material.
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