CN114360926A - Preparation method of elastic nitrogen-doped layered graphene electrode material - Google Patents
Preparation method of elastic nitrogen-doped layered graphene electrode material Download PDFInfo
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Abstract
In order to solve the technical problems of small capacity and volume expansion of a graphene material in the prior art, the invention provides a preparation method of an elastic nitrogen-doped layered graphene electrode material, which comprises the following steps: s1, oxidizing graphite to prepare graphite oxide; s2, mixing graphite oxide, water and urea under ultrasonic and stirring to obtain mixed slurry; then, placing the mixed slurry in a drying box for drying to obtain a mixed material; and S3, placing the mixture in a microwave oven for microwave radiation to obtain the elastic nitrogen-doped layered graphene electrode material. The method effectively improves the use stability of the graphene electrode material, and the prepared product has high capacity, low cyclic expansion rate and long cyclic service life by adopting the methods of modification, stacking reconstruction, microwave treatment and the like of the graphite oxide by the urea.
Description
Technical Field
The invention relates to the field of electrode materials, in particular to a preparation method of an elastic nitrogen-doped layered graphene electrode material.
Background
In recent years, with the continuous development of new energy and the continuous popularization of mobile equipment driven by new energy, such as new energy automobiles, the demand for a fast-charging new energy storage device with high capacity, high power and long service life is increasing. In particular, since the super capacitor has the advantages of fast charging, high power and long service life, the development and the demand for the super capacitor are increasing. Although research on electrode materials of supercapacitors is more, electrode materials which have the advantages of large capacity, fast charging, high power and long service life are still less, and further development is needed.
Graphene is considered to be a supercapacitor electrode material with great potential due to its excellent conductivity and ultra-high specific surface area. At present, graphene materials for developing supercapacitors include graphene, reduced graphene oxide, and nitrogen-doped graphene. The nitrogen-doped graphene has the advantages that the defects of the graphene can be effectively overcome due to the fact that the nitrogen-doped graphene has large specific surface area, high conductivity, controllable energy band structure and more active sites. Therefore, it is more widely used to construct a supercapacitor. However, the nitrogen-doped graphene material in powder form may undergo volume expansion during use due to irregular stacking during use, thereby significantly reducing the service life thereof.
In order to improve the situation, people assemble the nitrogen-doped graphene into structures such as three-dimensional structures, thin films and the like to form a more stable structure, so that the service life of the nitrogen-doped graphene is prolonged on the basis of ensuring the energy storage capacity of the nitrogen-doped graphene. The basic properties of some of these materials are now described.
Nitrogen-doped graphene three-dimensional material: compared with a three-dimensional graphene material, the material retains the characteristics of porous crosslinking and high specific surface area of the three-dimensional graphene material, and introduces nitrogen atoms into a graphene framework, so that the energy band structure of graphene is effectively changed, and the activity is improved. Because the nitrogen-doped graphene interlayer generates sufficient structural crosslinking, the interaction is obviously enhanced, and the volume expansion is not easy to generate. The methods for obtaining such materials are hydrothermal/solvothermal methods, flame methods, thermal cracking methods, microwave methods, etc.
Hydrothermal/solvothermal method: the basic process of synthesizing the nitrogen-doped graphene three-dimensional material by using a hydrothermal/solvent method is to disperse graphite oxide or graphene oxide synthesized by using a chemical stripping method (such as a Hummers method, a Brodie method, a Standenmaier method and the like) in water/organic solvent, add a nitrogen source (such as urea, hydrazine hydrate, ammonia water, melamine, hydroxylamine hydrochloride or hydroxylamine), react for a certain time in a hydrothermal reaction kettle at 120-220 ℃, cool and wash to prepare the nitrogen-doped graphene three-dimensional material. Examples of hydrothermal/solvothermal methods can be found in J.Mater.chem.A.2013, 1,2248-2255, J.Power Sources 2013,238, 492-.
Although researchers can successfully assemble graphite oxide or graphene oxide into three-dimensional graphene by a hydrothermal/solvent method and realize doping nitrogen atoms into a graphene framework so as to construct a nitrogen-doped graphene three-dimensional material, the nitrogen-doped graphene three-dimensional material has low reduction degree and poor conductivity and is not suitable for a high-power supercapacitor, and meanwhile, the preparation process of the method has high temperature, long time and low yield, so that the energy consumption and the production cost are high, and the production process generates high voltage, so that a huge safety problem exists.
A flame method: the basic process of synthesizing the nitrogen-doped graphene three-dimensional material by using a hydrothermal/solvent method is to disperse graphite oxide or graphene oxide synthesized by using a chemical stripping method (such as a Hummers method, a Brodie method, a Standenmaier method and the like) in a water/organic solvent, then soak PU foam in the graphite oxide or graphene oxide so that the graphene oxide is loaded on a PU foam framework, and finally remove the PU foam by using flame combustion of an alcohol burner to prepare the nitrogen-doped graphene three-dimensional material. An example of a flame method can be found in ACS Nano,2016,10(1), 453-462.
Although researchers can rapidly and efficiently prepare the nitrogen-doped graphene three-dimensional material by using a flame method, due to the fact that the temperature distribution of flame is uneven, the PU foam modified by graphene oxide is heated and combusted unevenly, the flame stability is poor, the difficulty of repeated operability is increased, and the prepared nitrogen-doped graphene three-dimensional material is unstable in property and poor in quality.
And (3) thermal cracking: the basic process of synthesizing the nitrogen-doped graphene three-dimensional material by using the thermal cracking method is to disperse graphite oxide or graphene oxide synthesized by using a chemical stripping method (such as a Hummers method, a Brodie method, a Standenmaier method and the like) in a water/organic solvent, then load the graphene oxide on other matrixes or compound the graphene oxide with other materials to form a three-dimensional composite material, and then transfer and thermally reduce the other matrixes or materials to obtain the nitrogen-doped graphene three-dimensional material. Examples of thermal cracking processes can be found in electrochim. acta,2017,241,1-9, adv. mat.,2017,29(36), 1701677.
Although researchers can successfully synthesize the nitrogen-doped graphene three-dimensional material with higher reduction degree and good conductivity through a thermal cracking method, the requirement on the synthesis equipment is high, long-time treatment needs to be carried out under the condition of high temperature (more than 600 ℃), the energy consumption is extremely high, and the cost is very high.
A microwave method: the basic process of synthesizing the nitrogen-doped graphene three-dimensional material by using the microwave method is to disperse graphite oxide or graphene oxide synthesized by using a chemical stripping method (such as a Hummers method, a Brodie method, a Standenmaier method and the like) in a water/organic solvent, then form a three-dimensional composite material by using a hydrothermal/solvothermal method, and finally prepare the nitrogen-doped graphene three-dimensional material by using microwave treatment. An example of a microwave process can be found in patent (CN 111099578A).
Although researchers can prepare the nitrogen-doped graphene three-dimensional material by using a microwave method, the method not only has multiple steps, but also uses a hydrothermal/solvothermal method, and simultaneously has long microwave reaction process time, so that the energy consumption is large, the cost is high, and the safety problem still exists.
Nitrogen-doped graphene film material: compared with the nitrogen-doped graphene three-dimensional material, the nitrogen-doped graphene film material not only has a porous cross-linked structure of the three-dimensional material, but also shows good mechanical properties (such as flexibility, stretchability, foldability and the like) due to the structural characteristics of the film, so that the nitrogen-doped graphene film material is more widely developed and used for flexible supercapacitors. The method for obtaining the material comprises a vacuum filtration method, a self-organization method and the like.
Vacuum filtration method: the basic process of synthesizing the nitrogen-doped graphene film material by a vacuum filtration method is to disperse graphite oxide/graphene oxide/nitrogen-doped graphene in water/organic solvent, add a certain amount of auxiliary agent, form a film structure by vacuum filtration, and finally obtain the nitrogen-doped graphene film material by high-temperature heat treatment. Examples of vacuum filtration methods can be found in appl.surf.Sci.,2019,485, 529-.
Although researchers successfully prepare the nitrogen-doped graphene film material through a vacuum filtration method, the reduction and nitrogen doping of the graphene oxide can be realized only through long-time high-temperature treatment, the requirement on equipment is high, the energy consumption is high, and the production cost is high.
Self-assembly method: the basic process of synthesizing the nitrogen-doped graphene film material by a self-assembly method is to disperse graphite oxide/graphene oxide in water, then inject the graphite oxide/graphene oxide into the bottom of an ethanol solution containing hydroxylamine, then use ethanol evaporation to realize hydroxylamine-assisted graphene oxide self-assembly, and finally perform high-temperature heat treatment to obtain the nitrogen-doped graphene film material. An example of a self-assembly process can be found in electrochim acta,2014,115,461-470.
Although researchers successfully prepare the nitrogen-doped graphene film material by a self-assembly method, like the vacuum filtration method, reduction and nitrogen doping of graphene oxide need to be realized by heat treatment at a higher temperature, so that the requirements on equipment are high, the energy consumption is high, and the production cost is high.
Although the methods all achieve certain effects, the method has the series problems of high energy consumption, high equipment requirement, complex production process, long time, high operation difficulty, poor reproducibility, high cost and the like. Therefore, the development of a technology capable of efficiently constructing a nitrogen-doped graphene material to have high energy storage capacity and simultaneously maintain small volume expansion in the use process is a key problem to be solved urgently.
Disclosure of Invention
In order to solve the technical problems of small capacity and small volume expansion of a graphene material in the prior art, the invention provides a preparation method of an elastic nitrogen-doped layered graphene electrode material, wherein graphene is subjected to nitrogen doping and assembled into a layered three-dimensional structure, when a supercapacitor electrode is constructed by the elastic nitrogen-doped layered graphene electrode material, the electrode for solving the technical problems can be obtained, and the electrode has the characteristics of high charging and discharging efficiency, large charging and discharging capacity and small volume expansion.
The invention aims to realize the technical scheme that the preparation method of the elastic nitrogen-doped layered graphene electrode material comprises the following steps:
s1, preparing graphite oxide by a chemical stripping method: oxidizing the flake graphite to prepare graphite oxide;
s2, preparing a mixture: mixing graphite oxide, water and urea under ultrasonic and stirring to obtain mixed slurry; then, placing the mixed slurry in a drying box for drying to obtain a mixed material;
s3, preparing an elastic nitrogen-doped layered three-dimensional graphene electrode material: and placing the mixture in a microwave oven for microwave radiation to obtain the elastic nitrogen-doped layered graphene electrode material.
Wherein, the graphite in the step S1 is flake graphite with the granularity of 300-355 meshes.
Wherein the chemical stripping method in step S1 is Hummers method, Brodie method or Standenmaier method.
The mixing in step S2 is to add graphite oxide into water for ultrasonic treatment to form uniform graphite oxide slurry, add urea, and perform stirring and ultrasonic treatment to form uniform mixed slurry.
In the step S2, the ultrasonic frequency is 40kHz, and the ultrasonic power is 90-150W; the ultrasonic time of the graphite oxide slurry is 30-90 min; the stirring temperature of the mixed slurry is 25-40 ℃, the stirring time is 30-60 min, and the ultrasonic time is 30 min.
Wherein, in the step S2, the drying temperature is 50 ℃, and the drying time is 48 h.
Wherein, in the step S2, the ratio of graphite oxide to urea is 1: (0.5-2).
Wherein the microwave power in the step S3 is 600-1000W; the microwave time is 50-180 s.
According to the invention, urea is used as a dispersing agent and a sacrificial coupling agent of graphene oxide, the amino group of urea is utilized to deprotonate the graphene oxide in water and the surface of the graphene oxide is negatively charged, so that better dispersion is realized, and simultaneously, after dehydration, coupling and assembly among graphene oxide sheets are realized by utilizing the strong electrostatic action of two amino groups of urea and the carboxyl group of the graphene oxide, so that the graphene oxide can more effectively absorb microwaves and convert the microwaves into heat, further, the microwaves are utilized for the first time to realize efficient reduction and nitrogen doping of the graphene oxide under the solid-phase condition, and the nitrogen-doped graphene obtained by reduction is prevented from being peeled, so that the three-dimensional nitrogen-doped graphene material is prepared. The method firstly solves the problem that the graphene oxide has limited microwave absorption capacity because the pi conjugated structure is damaged, so that the graphene oxide cannot be reduced by microwaves effectively. Meanwhile, the method successfully constructs the three-dimensional nitrogen-doped graphene material by utilizing the microwave for the first time. The preparation of graphite oxide, the mixing and drying of the slurry and the microwave treatment process are simple and easy to implement, and the used raw materials, reagents and equipment are all obtained by commercial purchase, so that the source is wide and the cost is low.
The invention effectively improves the use stability of the graphene electrode material, adopts the methods of modification, stacking reconstruction, microwave treatment and the like of the graphite oxide by urea, and has the advantages of high product capacity, low cycle expansion rate (the cycle expansion rate is the thickness ratio before and after the cycle), long cycle service life and the like: the specific surface area is adjustable and is 150-400m2(ii)/g; the second layer structure is elastic; the reduction degree is adjustable, and the C/O atomic ratio is 15-31; fourthly, the capacity is high and ranges from 200 to 300F/g; long cycle service life, capacity of 98-100% after 10000 cycles; sixthly, the volume expansion rate is low and is 0 to 3 percent.
Drawings
Fig. 1 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 1;
fig. 2 is a Scanning Electron Microscope (SEM) picture of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 1;
fig. 3 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 2;
fig. 4 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 3;
fig. 5 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 4;
fig. 6 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 5;
fig. 7 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 6;
fig. 8 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 7;
fig. 9 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 8;
FIG. 10 is an optical micrograph of graphite oxide before microwave treatment of comparative example 1;
FIG. 11 is an optical micrograph of graphite oxide after microwave treatment according to comparative example 1;
FIG. 12 is an optical micrograph of graphite oxide before microwave treatment of comparative example 2;
FIG. 13 is an optical micrograph of graphite oxide after microwave treatment according to comparative example 2;
fig. 14 is a graph showing the change of capacity retention rate of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 1 at a current density of 20A/g after 10000 cycles.
Detailed Description
The present invention is further illustrated by the following examples, which are not intended to be limiting and the starting materials, reagents and equipment used are commercially available. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.
Example 1
Firstly, preparing graphite oxide by using a Standnmaier method in a chemical stripping method:
measuring 17.5mL of concentrated sulfuric acid and 9mL of concentrated nitric acid in a 250mL flask, and stirring for 15 min; weighing 1g of crystalline flake graphite with the granularity of 300-355 meshes, and slowly adding the crystalline flake graphite into a flask; after stirring evenly, 11g of potassium chlorate is added to react for 96 hours; washing with 800mL of distilled water, washing with 5% dilute hydrochloric acid, and finally washing with distilled water to neutrality; drying the final graphite oxide product in an oven at 50 ℃ for 24 hours;
and secondly, mixing urea and graphite oxide:
weighing 0.5g of graphite oxide, placing the graphite oxide in a 250mL beaker, adding 100mL of distilled water, placing the beaker in an ultrasonic cleaning machine with the frequency of 40kHz and the power of 150W for ultrasonic treatment for 60min, then adding 0.5g of urea, stirring the mixture at 25 ℃ for 30min, then performing ultrasonic treatment again for 30min, and then placing the mixture in a 50 ℃ drying oven for drying for 48h to obtain a compound of the urea and the graphene oxide;
thirdly, microwave treatment of the compound of urea and graphene oxide:
and weighing 0.05g of the compound of the urea and the graphene oxide prepared in the second step, placing the compound in a 150mL beaker, and placing the beaker in a 1000W constant-power household microwave oven for microwave treatment for 90s to prepare the elastic nitrogen-doped layered three-dimensional graphene electrode material.
Example 2
Firstly, preparing graphite oxide by a Hummers method in a chemical stripping method:
weighing 1g of crystalline flake graphite with the granularity of 300-355 meshes and 0.5g of sodium nitrate, putting the crystalline flake graphite and the sodium nitrate into a 250mL round-bottom flask, and measuring the concentration in percentage by weightAdding 23mL of 98% concentrated sulfuric acid into the round-bottom flask, adding magnetons, placing the round-bottom flask into an ice-water bath, stirring for 30min, weighing 3g of potassium permanganate, adding the potassium permanganate into the reactor, continuing to stir for 1H, after the reaction is finished, transferring the reactor into a 35 ℃ water bath, continuing to stir for 30min, measuring 50mL of distilled water, adding the distilled water into the round-bottom flask, transferring the round-bottom flask into an oil bath at 98 ℃, continuing to stir for 15min, sequentially adding 140mL of distilled water and 30% H by mass fraction2O210mL, centrifuging after the reaction system finally becomes bright yellow, washing with 500mL of hydrochloric acid with 5% of HCl in mass fraction and distilled water in sequence until the solution becomes neutral, and drying the final graphite oxide product in a 50 ℃ oven for 24 hours;
and secondly, mixing urea and graphite oxide:
weighing 0.5g of graphite oxide, placing the graphite oxide in a 250mL beaker, adding 100mL of distilled water, placing the beaker in an ultrasonic cleaning machine with the frequency of 40Hz and the power of 90W, carrying out ultrasonic treatment for 90min, then adding 0.25g of urea, stirring the mixture at 35 ℃ for 60min, then carrying out ultrasonic treatment again for 30min, and then placing the mixture in a 50 ℃ drying oven for drying for 48h to obtain a compound of the urea and the graphene oxide;
thirdly, microwave treatment of the compound of urea and graphene oxide:
and weighing 0.05g of the compound of the urea and the graphene oxide prepared in the second step, placing the compound into a 150mL beaker, and placing the beaker into a 600W constant-power household microwave oven for microwave treatment for 180s to prepare the elastic nitrogen-doped layered three-dimensional graphene electrode material.
Example 3
Firstly, preparing graphite oxide by a Brodie method in a chemical stripping method:
weighing 2g of crystalline flake graphite with the granularity of 300-355 meshes, adding the crystalline flake graphite into 3mL of crystalline flake graphite containing 3gK2S2O8And 3gP2O5Heating the graphite in concentrated sulfuric acid at the temperature of 80 ℃ for 6 hours, cooling the graphite to room temperature, diluting the graphite with distilled water, washing the graphite to be neutral, drying the graphite to obtain pre-oxidized graphite, weighing 1g of the obtained pre-oxidized graphite, adding the graphite into 46mL of concentrated sulfuric acid, adding 3g of potassium permanganate under the condition of ice-water bath, and reacting for 2 hours at the temperature of 35 ℃. In the reactionThen adding 46mL of distilled water, slowly adding 280mL of distilled water and 5mL of 30% hydrogen peroxide, centrifuging while hot, finally washing with 500mL of 5% diluted hydrochloric acid and a large amount of distilled water to be neutral, and finally placing the obtained graphite oxide product in a 50 ℃ oven for drying for 24 hours;
and secondly, mixing urea and graphite oxide:
weighing 0.5g of graphite oxide, placing the graphite oxide in a 250mL beaker, adding 100mL of distilled water, placing the beaker in an ultrasonic cleaning machine with the frequency of 40kHz and the power of 120W for ultrasonic treatment for 30min, then adding 1g of urea, stirring the mixture at 40 ℃ for 45min, then performing ultrasonic treatment again for 30min, and then placing the mixture in a 50 ℃ drying oven for drying for 48h to obtain a compound of the urea and the graphene oxide;
thirdly, microwave treatment of the compound of urea and graphene oxide:
and weighing 0.05g of the compound of the urea and the graphene oxide prepared in the second step, placing the compound in a 150mL beaker, and placing the beaker in a 700W constant-power household microwave oven for microwave treatment for 120s to prepare the elastic nitrogen-doped layered three-dimensional graphene electrode material.
Example 4
Firstly, preparing graphite oxide by a Hummers method in a chemical stripping method:
weighing 1g of crystalline flake graphite with the granularity of 300-355 meshes and 0.5g of sodium nitrate, placing the crystalline flake graphite and 0.5g of sodium nitrate into a 250mL round-bottom flask, weighing 23mL of concentrated sulfuric acid with the weight percentage concentration of 98%, adding the concentrated sulfuric acid into the round-bottom flask, adding magnetons, placing the round-bottom flask into an ice-water bath, stirring for 30min, weighing 3g of potassium permanganate into a reactor, continuing to stir for 1H, after the reaction is finished, transferring the reactor into a 35 ℃ water bath, continuing to stir for 30min, weighing 50mL of distilled water, adding the distilled water into the round-bottom flask, transferring the round-bottom flask into a 98 ℃ oil bath, continuing to stir for 15min, sequentially adding 140mL of distilled water and 30% of H by mass fraction2O210mL, centrifuging after the reaction system finally becomes bright yellow, washing with 500mL of hydrochloric acid with 5% of HCl in mass fraction and distilled water in sequence until the solution becomes neutral, and drying the final graphite oxide product in a 50 ℃ oven for 24 hours;
and secondly, mixing urea and graphite oxide:
weighing 0.5g of graphite oxide, placing the graphite oxide in a 250mL beaker, adding 100mL of distilled water, placing the beaker in an ultrasonic cleaning machine with the frequency of 40kHz and the power of 135W for ultrasonic treatment for 40min, then adding 0.75g of urea, stirring the mixture for 50min at 30 ℃, then performing ultrasonic treatment again for 30min, and then placing the mixture in a 50 ℃ drying oven for drying for 48h to obtain a compound of the urea and the graphene oxide;
thirdly, microwave treatment of the compound of urea and graphene oxide:
and weighing 0.05g of the compound of the urea and the graphene oxide prepared in the second step, placing the compound into a 150mL beaker, and placing the beaker into a 900W constant-power household microwave oven for microwave treatment for 50s to prepare the elastic nitrogen-doped layered three-dimensional graphene electrode material.
Example 5
Firstly, preparing graphite oxide by a Hummers method in a chemical stripping method:
weighing 1g of crystalline flake graphite with the granularity of 300-355 meshes, placing the crystalline flake graphite into a 250mL round-bottom flask, weighing 23mL of concentrated sulfuric acid with the weight percentage concentration of 98%, adding the concentrated sulfuric acid into the round-bottom flask, adding magnetons, placing the round-bottom flask into an ice-water bath, stirring for 60min, weighing 3g of potassium permanganate into a reactor, continuing to stir for 1H, after the reaction is completed, transferring the reactor into a 35 ℃ water bath, continuing to stir for 30min, weighing 50mL of distilled water, adding the distilled water into the round-bottom flask, transferring the round-bottom flask into a 98 ℃ oil bath, continuing to stir for 15min, sequentially adding 140mL of distilled water and 30% of H by mass fraction into the oil bath, and sequentially adding 140mL of distilled water and 30% of H2O210mL, centrifuging after the reaction system finally becomes bright yellow, washing with 500mL of hydrochloric acid with 5% of HCl in mass fraction and distilled water in sequence until the solution becomes neutral, and drying the final graphite oxide product in a 50 ℃ oven for 24 hours;
and secondly, mixing urea and graphite oxide:
weighing 0.5g of graphite oxide, placing the graphite oxide in a 250mL beaker, adding 100mL of distilled water, placing the beaker in an ultrasonic cleaning machine with the frequency of 40kHz and the power of 105W for ultrasonic treatment for 70min, then adding 0.35g of urea, stirring the mixture at 28 ℃ for 40min, then performing ultrasonic treatment again for 30min, and then placing the mixture in a 50 ℃ drying oven for drying for 48h to obtain a compound of the urea and the graphene oxide;
thirdly, microwave treatment of the compound of urea and graphene oxide:
0.05g of the compound of the urea and the graphene oxide prepared in the second step is weighed and placed in a 150mL beaker, and the beaker is placed in a 800W constant-power household microwave oven for microwave treatment for 160s to prepare the elastic nitrogen-doped layered three-dimensional graphene electrode material.
Example 6
Firstly, preparing graphite oxide by a Brodie method in a chemical stripping method:
weighing 2g of crystalline flake graphite with the granularity of 300-355 meshes, adding the crystalline flake graphite into 3mL of crystalline flake graphite containing 3gK2S2O8And 3gP2O5Heating the graphite in concentrated sulfuric acid at the temperature of 80 ℃ for 6 hours, cooling the graphite to room temperature, diluting the graphite with distilled water, washing the graphite to be neutral, drying the graphite to obtain pre-oxidized graphite, weighing 1g of the obtained pre-oxidized graphite, adding the graphite into 46mL of concentrated sulfuric acid, adding 3g of potassium permanganate under the condition of ice-water bath, and reacting for 2 hours at the temperature of 35 ℃. Adding 46mL of distilled water after reaction, slowly adding 280mL of distilled water and 5mL of 30% hydrogen peroxide, centrifuging while hot, finally washing with 500mL of 5% diluted hydrochloric acid and a large amount of distilled water to be neutral, and finally drying the obtained graphite oxide product in a 50 ℃ oven for 24 hours;
and secondly, mixing urea and graphite oxide:
weighing 0.5g of graphite oxide, placing the graphite oxide in a 250mL beaker, adding 100mL of distilled water, placing the beaker in an ultrasonic cleaning machine with the frequency of 40kHz and the power of 150W for ultrasonic treatment for 50min, then adding 0.4g of urea, stirring the mixture at 40 ℃ for 60min, then performing ultrasonic treatment again for 30min, and then placing the mixture in a 50 ℃ drying oven for drying for 48h to obtain a compound of the urea and the graphene oxide;
thirdly, microwave treatment of the compound of urea and graphene oxide:
and weighing 0.05g of the compound of the urea and the graphene oxide prepared in the second step, placing the compound into a 150mL beaker, and placing the beaker into a 900W constant-power household microwave oven for microwave treatment for 100s to prepare the elastic nitrogen-doped layered three-dimensional graphene electrode material.
Example 7
Firstly, preparing graphite oxide by using a Standnmaier method in a chemical stripping method:
measuring 17.5mL of concentrated sulfuric acid and 9mL of concentrated nitric acid in a 250mL flask, and stirring for 15 min; weighing 1g of crystalline flake graphite with the granularity of 300-355 meshes, and slowly adding the crystalline flake graphite into a flask; after stirring evenly, 11g of potassium chlorate is added to react for 96 hours; washing with 800mL of distilled water, washing with 5% dilute hydrochloric acid, and finally washing with distilled water to neutrality; drying the final graphite oxide product in an oven at 50 ℃ for 24 hours;
and secondly, mixing urea and graphite oxide:
weighing 0.5g of graphite oxide, placing the graphite oxide in a 250mL beaker, adding 100mL of distilled water, placing the beaker in an ultrasonic cleaning machine with the frequency of 40kHz and the power of 120W for ultrasonic treatment for 80min, then adding 0.8g of urea, stirring the mixture for 50min at 25 ℃, then performing ultrasonic treatment again for 30min, and then placing the mixture in a 50 ℃ drying oven for drying for 48h to obtain a compound of the urea and the graphene oxide;
thirdly, microwave treatment of the compound of urea and graphene oxide:
and weighing 0.05g of the compound of the urea and the graphene oxide prepared in the second step, placing the compound into a 150mL beaker, and placing the beaker into a 700W constant-power household microwave oven for microwave treatment for 60s to prepare the elastic nitrogen-doped layered three-dimensional graphene electrode material.
Example 8
Firstly, preparing graphite oxide by a Hummers method in a chemical stripping method:
weighing 1g of crystalline flake graphite with the granularity of 300-355 meshes, placing the crystalline flake graphite into a 250mL round-bottom flask, weighing 23mL of concentrated sulfuric acid with the weight percentage concentration of 98%, adding the concentrated sulfuric acid into the round-bottom flask, adding magnetons, placing the round-bottom flask into an ice-water bath, stirring for 60min, weighing 3g of potassium permanganate into a reactor, continuing to stir for 1H, after the reaction is completed, transferring the reactor into a 35 ℃ water bath, continuing to stir for 30min, weighing 50mL of distilled water, adding the distilled water into the round-bottom flask, transferring the round-bottom flask into a 98 ℃ oil bath, continuing to stir for 15min, sequentially adding 140mL of distilled water and 30% of H by mass fraction into the oil bath, and sequentially adding 140mL of distilled water and 30% of H2O210mL, after the reaction system finally became bright yellowCentrifuging, washing with 500mL of hydrochloric acid with 5% of HCl in mass fraction and distilled water in sequence until the solution becomes neutral, and drying the final graphite oxide product in a 50 ℃ oven for 24 hours;
and secondly, mixing urea and graphite oxide:
weighing 0.5g of graphite oxide, placing the graphite oxide in a 250mL beaker, adding 100mL of distilled water, placing the beaker in an ultrasonic cleaning machine with the frequency of 40kHz and the power of 105W for ultrasonic treatment for 50min, then adding 0.3g of urea, stirring the mixture at 30 ℃ for 35min, then performing ultrasonic treatment again for 30min, and then placing the mixture in a 50 ℃ drying oven for drying for 48h to obtain a compound of the urea and the graphene oxide;
thirdly, microwave treatment of the compound of urea and graphene oxide:
and weighing 0.05g of the compound of the urea and the graphene oxide prepared in the second step, placing the compound into a 150mL beaker, and placing the beaker into a 900W constant-power household microwave oven for microwave treatment for 80s to prepare the elastic nitrogen-doped layered three-dimensional graphene electrode material.
Comparative example 1
Firstly, preparing graphite oxide by a Hummers method in a chemical stripping method:
weighing 1g of crystalline flake graphite with the granularity of 300-355 meshes and 0.5g of sodium nitrate, placing the crystalline flake graphite and 0.5g of sodium nitrate into a 250mL round-bottom flask, weighing 23mL of concentrated sulfuric acid with the weight percentage concentration of 98%, adding the concentrated sulfuric acid into the round-bottom flask, adding magnetons, placing the round-bottom flask into an ice-water bath, stirring for 30min, weighing 3g of potassium permanganate into a reactor, continuing to stir for 1H, after the reaction is finished, transferring the reactor into a 35 ℃ water bath, continuing to stir for 30min, weighing 50mL of distilled water, adding the distilled water into the round-bottom flask, transferring the round-bottom flask into a 98 ℃ oil bath, continuing to stir for 15min, sequentially adding 140mL of distilled water and 30% of H by mass fraction2O210mL, centrifuging after the reaction system finally becomes bright yellow, washing with 500mL of hydrochloric acid with 5% of HCl in mass fraction and distilled water in sequence until the solution becomes neutral, and drying the final graphite oxide product in a 50 ℃ oven for 24 hours;
step two, microwave treatment of graphite oxide:
0.05g of the graphite oxide prepared in the first step was weighed into a 150mL beaker, and the beaker was placed in a 1000W constant power household microwave oven for 90 seconds to prepare graphene.
Comparative example 2
Firstly, preparing graphite oxide by a Hummers method in a chemical stripping method:
weighing 1g of crystalline flake graphite with the granularity of 300-355 meshes and 0.5g of sodium nitrate, placing the crystalline flake graphite and 0.5g of sodium nitrate into a 250mL round-bottom flask, weighing 23mL of concentrated sulfuric acid with the weight percentage concentration of 98%, adding the concentrated sulfuric acid into the round-bottom flask, adding magnetons, placing the round-bottom flask into an ice-water bath, stirring for 30min, weighing 3g of potassium permanganate into a reactor, continuing to stir for 1H, after the reaction is finished, transferring the reactor into a 35 ℃ water bath, continuing to stir for 30min, weighing 50mL of distilled water, adding the distilled water into the round-bottom flask, transferring the round-bottom flask into a 98 ℃ oil bath, continuing to stir for 15min, sequentially adding 140mL of distilled water and 30% of H by mass fraction2O210mL, centrifuging after the reaction system finally becomes bright yellow, washing with 500mL of hydrochloric acid with 5% of HCl in mass fraction and distilled water in sequence until the solution becomes neutral, and drying the final graphite oxide product in a 50 ℃ oven for 24 hours;
step two, microwave treatment of graphite oxide:
0.05g of the graphite oxide prepared in the first step is weighed and placed in a 150mL beaker, and the beaker is placed in a 1000W constant-power household microwave oven for microwave treatment for 30min to prepare graphene.
Effects of the embodiment
(1) The elastic nitrogen-doped layered three-dimensional graphene electrode materials in examples 1 to 8 were respectively subjected to tests of specific surface area, C/O atomic ratio, N atom content, charge transfer impedance, specific capacitance, capacity retention rate, volume expansion rate, and the like, the test equipment is shown in table 1, and the test results are shown in table 2.
(2) The elastic nitrogen-doped layered three-dimensional graphene electrode materials in examples 1 to 8 were subjected to charge transfer impedance, specific capacitance, and capacity retention ratio tests, respectively, using a three-electrode system.
(3) The assembly method of the working electrode in the three-electrode system comprises the following steps: respectively and uniformly loading 2mg of the elastic nitrogen-doped layered three-dimensional graphene electrode material in the embodiments 1-8 between two pieces of foamed nickel, and pressing the material under the pressure of 8Mpa for 10min to prepare a working electrode.
(4) The counter electrode used in the three-electrode system is a platinum sheet electrode, the reference electrode used is a saturated calomel electrode, the electrolyte solution used is 2mol/L KOH aqueous solution, and the test equipment is Shanghai Hua 660E electrochemical workstation. The charge transfer impedance was obtained by an electrochemical impedance spectroscopy module (a.c. impedance) test in the shanghai hua 660E electrochemical workstation. Specific capacitance (C)s) Testing by a constant-current charge-discharge module (chronotropic measurement) in Shanghai Chenghua 660E electrochemical workstation by using a formula CsI, t, m, and Δ V represent a discharge current (a), a discharge time(s), an active material mass (g), and a potential difference (V), respectively.
(5) The volume expansion ratio is [ (thickness of the working electrode sheet after the cycle test-thickness of the working electrode sheet before the cycle test)/thickness of the working electrode sheet before the cycle test ] × 100%.
TABLE 1
TABLE 2
Examples and comparative examples will now be further illustrated with reference to the accompanying drawings:
fig. 1 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 1; fig. 2 is a Scanning Electron Microscope (SEM) picture of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 1; fig. 3 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 2; fig. 4 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 3; fig. 5 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 4; fig. 6 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 5; fig. 7 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 6; fig. 8 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 7; fig. 9 is an optical microscope photograph of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 8. As can be seen from fig. 1, the graphite oxide has been successfully converted into the nitrogen-doped three-dimensional graphene electrode material with elasticity from example 1. As can be seen from fig. 2, the elastic nitrogen-doped three-dimensional graphene electrode material prepared in example 1 has a distinct layered structure. As is clear from fig. 3, 4, 5, 6, 7, 8, and 9, in each of examples 2, 3, 4, 5, 6, 7, and 8, an elastic nitrogen-doped three-dimensional layered graphene electrode material similar to that of example 1 was obtained.
FIG. 10 is an optical micrograph of graphite oxide before microwave treatment of comparative example 1; FIG. 11 is an optical micrograph of graphite oxide after microwave treatment according to comparative example 1; FIG. 12 is an optical micrograph of graphite oxide before microwave treatment of comparative example 1; FIG. 13 is an optical micrograph of graphite oxide after microwave treatment according to comparative example 1. As can be seen from fig. 10 and 11, the graphite oxide did not change significantly before and after the microwave treatment, which indicates that the method provided in comparative example 1 could not reduce the graphite oxide, thereby producing a layered three-dimensional layered graphene electrode material. As is clear from fig. 12 and 13, even if the graphite oxide is treated with microwaves for a long time, the graphite oxide cannot be reduced to form the three-dimensional layered graphene electrode material.
Fig. 14 is a graph showing the change of capacity retention rate of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 1 at a current density of 20A/g after 10000 cycles. As can be seen from fig. 14, after 10000 cycles, the capacity of the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared in example 1 is not attenuated, which indicates that the elastic nitrogen-doped layered three-dimensional graphene electrode material has a very excellent cycle life.
Therefore, as can be seen from the above drawings, the method provided by the invention successfully realizes the reduction of graphene oxide in microwave, prepares a high-performance elastic nitrogen-doped layered three-dimensional graphene electrode material, and solves the problem that the graphene oxide cannot be reduced by microwave because the microwave absorption capacity is limited due to the damage of the pi conjugated structure.
According to the detection results and the attached drawings, the elastic nitrogen-doped layered three-dimensional graphene electrode material prepared by the invention has the advantages of high capacity, low cyclic expansion rate (the cyclic expansion rate is the thickness ratio before and after the cycle), long cycle service life and the like: the specific surface area is adjustable and moderate, 150-400 m2(ii)/g; the second layer structure is elastic; the reduction degree is adjustable, and the atomic ratio of C/O is 15-31; fourthly, the capacity is high and ranges from 200 to 300F/g; the circulation volume expansion rate is low, 0-3%; sixthly, the cycle service life is long, 10000 circles and the capacity is kept between 98 and 100 percent.
It should be understood that the examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that any changes and modifications to the present invention may occur to those skilled in the art after reading the present teachings, and such equivalents are also intended to be limited by the appended claims.
Claims (9)
1. The preparation method of the elastic nitrogen-doped layered graphene electrode material is characterized by comprising the following steps of:
s1, preparing graphite oxide by a chemical stripping method: oxidizing the flake graphite to prepare graphite oxide;
s2, preparing a mixture: mixing graphite oxide, water and urea under ultrasonic and stirring to obtain mixed slurry; then, placing the mixed slurry in a drying box for drying to obtain a mixed material;
s3, preparing an elastic nitrogen-doped layered three-dimensional graphene electrode material: and placing the mixture in a microwave oven for microwave radiation to obtain the elastic nitrogen-doped layered graphene electrode material.
2. The method for preparing the elastic nitrogen-doped layered graphene electrode material according to claim 1, wherein the graphite in the step S1 is flake graphite with a particle size of 300-355 meshes.
3. The method for preparing the elastic nitrogen-doped layered graphene electrode material according to claim 1, wherein the chemical exfoliation method in the step S1 is Hummers method, Brodie method or Standenmaier method.
4. The method for preparing a hydrogen-elastic nitrogen-doped layered graphene electrode material according to claim 1, wherein the mixing in step S2 is to add graphite oxide into water for ultrasound to form a uniform graphite oxide slurry, then add urea, stir and perform ultrasound to form a uniform mixed slurry.
5. The preparation method of the elastic nitrogen-doped layered graphene electrode material according to claim 4, wherein in the step S2, the ultrasonic frequency is 40kHz, and the ultrasonic power is 90-150W; the ultrasonic time of the graphite oxide slurry is 30-90 min; the stirring temperature of the mixed slurry is 25-40 ℃, the stirring time is 30-60 min, and the ultrasonic time is 30 min.
6. The method for preparing the elastic nitrogen-doped layered graphene electrode material according to claim 1, wherein the drying temperature in the step S2 is 50 ℃ and the drying time is 48 h.
7. The method for preparing the elastic nitrogen-doped layered graphene electrode material according to any one of claims 1 to 6, wherein the ratio of graphite oxide to urea in the step S2 is 1: (0.5-2).
8. The method for preparing the elastic nitrogen-doped layered graphene electrode material according to claim 7, wherein the ratio of graphite oxide to urea in step S2 is 1: (0.8 to 1.2).
9. The preparation method of the elastic nitrogen-doped layered graphene electrode material according to any one of claims 1 to 5, wherein the microwave power in the step S3 is 600-1000W; the microwave time is 50-180 s.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103840160A (en) * | 2012-11-23 | 2014-06-04 | 海洋王照明科技股份有限公司 | Nitrogen-doped graphene composite material and preparation method thereof |
| CN104008894A (en) * | 2013-02-21 | 2014-08-27 | 海洋王照明科技股份有限公司 | Nitrogen-doped graphene material, preparation method thereof, nitrogen-doped graphene electrode, and electrochemical capacitor |
| TW202124274A (en) * | 2019-12-20 | 2021-07-01 | 鐘明吉 | Method for preparing graphene sheet by using supercritical fluid intercalation step and microwave expansion step |
-
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103840160A (en) * | 2012-11-23 | 2014-06-04 | 海洋王照明科技股份有限公司 | Nitrogen-doped graphene composite material and preparation method thereof |
| CN104008894A (en) * | 2013-02-21 | 2014-08-27 | 海洋王照明科技股份有限公司 | Nitrogen-doped graphene material, preparation method thereof, nitrogen-doped graphene electrode, and electrochemical capacitor |
| TW202124274A (en) * | 2019-12-20 | 2021-07-01 | 鐘明吉 | Method for preparing graphene sheet by using supercritical fluid intercalation step and microwave expansion step |
Non-Patent Citations (1)
| Title |
|---|
| 王灿: "碳纳米管和石墨烯的合成及其氮掺杂", 《中国博士学位论文全文数据库工程科技Ⅰ辑》 * |
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