CN115188601A - Preparation of nitrogen-doped interconnected hollow carbon nano onion structure with high energy density and high power density - Google Patents

Preparation of nitrogen-doped interconnected hollow carbon nano onion structure with high energy density and high power density Download PDF

Info

Publication number
CN115188601A
CN115188601A CN202210188862.6A CN202210188862A CN115188601A CN 115188601 A CN115188601 A CN 115188601A CN 202210188862 A CN202210188862 A CN 202210188862A CN 115188601 A CN115188601 A CN 115188601A
Authority
CN
China
Prior art keywords
carbon nano
hollow carbon
nitrogen
interconnected hollow
doped
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202210188862.6A
Other languages
Chinese (zh)
Inventor
张晨光
张文超
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tianjin University of Technology
Original Assignee
Tianjin University of Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tianjin University of Technology filed Critical Tianjin University of Technology
Priority to CN202210188862.6A priority Critical patent/CN115188601A/en
Publication of CN115188601A publication Critical patent/CN115188601A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/32—Carbon-based
    • H01G11/36—Nanostructures, e.g. nanofibres, nanotubes or fullerenes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
    • H01G11/86—Processes for the manufacture of hybrid or EDL capacitors, or components thereof specially adapted for electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/13—Energy storage using capacitors

Abstract

The invention discloses a preparation method of a nitrogen-doped interconnected hollow carbon nano onion structure with uniform size and application of the structure as a high-performance supercapacitor electrode material. The preparation of the interconnected hollow carbon nano onion comprises the processes of preparing a metal oxide nano particle template, carbonizing, purifying, graphitizing, doping nitrogen and the like to obtain the nitrogen-doped interconnected hollow carbon nano onion structure. In the structure, the graphite layers are interconnected through covalent bonds to form a carbon onion carbon skeleton and an interconnected pore structure, so that the carbon onion carbon skeleton has the structural advantages of high specific surface area, high conductivity and rapid ion transmission, and can simultaneously obtain high energy density and high power density when used as a supercapacitor electrode material.The highest energy density of the device can reach 168.9Wh kg ‑1 And at 45.2Wh kg ‑1 Can reach 400kW kg under the energy density ‑1 High power density of (2). The invention provides a structural design and a preparation scheme for the supercapacitor electrode material with high energy density and high power density.

Description

Preparation of nitrogen-doped interconnected hollow carbon nano onion structure with high energy density and high power density
The technical field is as follows:
the invention belongs to the technical field of carbon material preparation, and particularly relates to a preparation method of a nitrogen-doped interconnected hollow carbon nano onion structure with uniform size.
Background art:
the super capacitor is a novel electrochemical energy storage device and has the advantages of high power density, high rate performance, long service life, stability and the like. At present, carbon-based materials such as activated carbon, carbon nanotubes and graphene are commonly used as electrode materials of the super capacitorThe power density can reach 30kW kg -1 The number of the battery is 1-2 orders higher than that of the battery, and the battery has wide application in the fields of wind power generation systems, new energy vehicles, intelligent distributed power grid systems, distributed energy storage systems, military equipment, energy recovery and the like. At present, the energy density of the commercial super capacitor is less than 10Wh kg -1 Much less than 200Wh kg of battery -1 The low energy density restricts the application of the super capacitor in different scenes. Therefore, in order to achieve better applications of supercapacitors in different application areas, the electrode material needs to have both high energy density and high power density.
The ionic liquid electrolyte can obviously improve the energy density of the super capacitor, but the ionic liquid electrolyte has large ion size and high viscosity, and can reduce the power density. In the common carbon-based electrode material at present, activated carbon mainly takes micropores as main materials, the pore structure is complex, anions and cations in ionic liquid electrolyte are difficult to diffuse in the pores, the rate capability is poor, and although the energy density is improved, the power density is sacrificed. Carbon-based materials such as carbon nanotubes and graphene films have irregular pore structures, and graphene sheets are stacked, so that the rate capability and the power density are influenced.
The carbon nano onion is a spherical structure with a unique concentric graphite shell layer winding, has structural advantages in the application of high-power energy storage, and has been proved by documents that the surface of the carbon nano onion is beneficial to the infiltration of electrolyte, the ion accessibility is good, the ion migration is fast, the carbon nano onion can still maintain the fast charge and discharge capacity at the low temperature in the ionic liquid, and the carbon nano onion is expected to obtain high power density in the ionic liquid. At present, however, the carbon nano onion particles are isolated from each other or are connected only by Van der Waals force, so that the conductivity is low, and the improvement of the specific capacitance and the energy density is influenced. Therefore, a novel structure based on carbon nano onions is developed, the energy density of the carbon nano onions is improved on the premise of ensuring the high power density of the carbon nano onions, and the carbon nano onions have great significance for the ionic liquid super capacitor with high energy density and high power density.
The invention content is as follows:
in order to overcome the defects of the prior art, the invention synthesizes a nitrogen-doped interconnected hollow carbon nano onion structure. The graphite layers with covalently interconnected surfaces are formed by means of compact arrangement of metal oxide nanoparticles, an interconnected hollow carbon nano onion structure in an integral range is constructed, the electrical conductivity and specific capacitance of the material can be improved by integral interconnection of the graphite layers, the hollow structure can provide a charge storage space and improve the mass specific capacitance, and the high graphitization of the graphite layers is beneficial to the improvement of the electrical conductivity and the rapid migration of ions. The nitrogen element doping can provide more electrochemical reaction sites, and the specific capacitance of the composite material is improved. The material also has an interconnected and intercommunicated hierarchical pore structure comprising a large number of micropores and mesopores, and is beneficial to the rapid migration and storage of large-size ions in the material. The structural advantages and characteristics of the nitrogen-doped interconnected hollow carbon nano onion enable the material to have high energy density and high power density
The technical method for solving the technical problems comprises the following steps: a method for preparing a nitrogen-doped interconnected hollow carbon nano onion structure with both high energy density and high power density, the method comprising:
1)Fe 3 O 4 preparing a nano-particle template: firstly, fe is mixed according to a specific proportion 2 O 3 Oleic acid and 1-octadecene in N 2 Mixing and stirring in the atmosphere, preserving the temperature of the mixed solution at 100-340 ℃ for reaction, and finally synthesizing the monodisperse uniform-size Fe with the surface modified with the oleic acid ligand 3 O 4 Cooling the nano particles to room temperature, and purifying and diluting the nano particles by using a non-polar organic solvent to obtain Fe 3 O 4 A dispersion of nanoparticles.
2) Carbonizing: mixing Fe 3 O 4 Drying the nano-particle dispersion liquid in a container, heating to a certain temperature in Ar atmosphere, preserving heat, and cooling to room temperature to obtain the coated Fe 3 O 4 Interconnected carbon structures of nanoparticles.
3) And (3) purification: removal of Fe by hydrochloric acid solution 3 O 4 And washing and drying the nano particles to obtain the interconnected hollow carbon structure.
4) Graphitization: and (3) placing the interconnected hollow carbon structure in Ar atmosphere, heating to a certain temperature, carrying out heat preservation graphitization treatment, and cooling to room temperature to obtain the interconnected hollow carbon nano onion structure.
5) Doping of nitrogen: and (2) mixing the interconnected hollow carbon nano onion and urea according to a certain proportion, grinding, dispersing in a solvent for hydrothermal reaction, washing and drying a sample after the reaction is finished, and then placing the sample in an Ar atmosphere for high-temperature annealing treatment to obtain the nitrogen-doped interconnected hollow carbon nano onion structure.
6) Preparing an electrode and assembling a super capacitor: and coating the electrode material on a current collector, and drying to obtain the nitrogen-doped interconnected hollow carbon nano onion electrode. And taking the electrode as a positive symmetrical electrode and a negative symmetrical electrode, inserting a diaphragm in the middle, and packaging the super capacitor to obtain the super capacitor device.
Said Fe 2 O 3 The mol ratio of the Fe and the oleic acid is 1: 2-1: 10, and Fe with different sizes can be synthesized by adjusting the ratio 3 O 4 And (3) nanoparticles.
Said N is 2 The heat preservation process in the atmosphere can be divided into three stages: 1) Heating to 100-140 deg.c and maintaining for 20-60 min; 2) Heating to 200-240 deg.c and maintaining for 20-60 min; 3) Heating to 300-340 deg.c and maintaining for 20-240 min.
The carbonization stage is to introduce 60-100 sccm of argon into the tubular furnace and keep the temperature for 40-80 min within the temperature range of 400-600 ℃.
The purification stage will be stirring in 3-9M HCl solution for 12-36 h.
The graphitization stage is to introduce 80-120 sccm of argon into the tubular furnace and to preserve heat for 1-3 h at 800-1400 ℃.
The proportion of the interconnected hollow carbon nano onions to the urea in the nitrogen doping stage is 1: 1-1: 5.
The high-temperature annealing treatment in the nitrogen doping stage is to introduce 60-100 sccm of argon into the tubular furnace and keep the temperature for 40-80 min within the temperature range of 700-1000 ℃.
The ratio of the electrode material, the conductive additive and the polyvinylidene fluoride is 8: 1 when the electrode is coated.
The invention has the beneficial effects that: the invention provides a nitrogen-doped interconnected hollow carbon nano ocean with high energy density and high power densityA process for preparing the electrode material with scallion structure includes such steps as preparing the monodispersed ferroferric oxide nanoparticles with uniform size, carbonizing the surface ligand, and Fe 3 O 4 The nitrogen-doped interconnected hollow carbon nano onion structure is obtained by the processes of purification, graphitization of a carbon layer, nitrogen doping and the like, and pure 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF) is used 4 ) And assembling the super capacitor by using the ionic liquid electrolyte. The super capacitor has the advantages of high specific surface area, high conductivity and rapid ion transmission of nitrogen-doped interconnected hollow carbon nano onions, and the highest energy density of the super capacitor can reach 168.9Wh kg -1 And at 45.2Wh kg -1 Can reach 400kW kg under the energy density -1 The capacity retention ratio after 5 ten thousand cycles was 98.2%. The novel electrode material with the nitrogen-doped interconnected hollow carbon nano onion structure, which is prepared by the invention, provides a structural design and a preparation scheme for a supercapacitor electrode material with high energy density and high power density.
Description of the drawings:
FIG. 1 is a flow chart of a method for preparing nitrogen-doped interconnected hollow carbon nano-onions;
FIG. 2 is a scanning electron microscope image of a 5.6nm nitrogen-doped interconnected hollow carbon nano-onion sample from example 1;
FIG. 3a is a TEM image of a 5.6nm interconnected hollow carbon nano-onion sample from example 1; FIG. 3b is a TEM image of a 5.6nm N-doped interconnected hollow carbon nano-onion sample as in example 1;
FIG. 4 is a STEM-HAADF image and elemental distribution plots of C, N, O of 5.6nm nitrogen-doped interconnected hollow carbon nano-onions samples from example 1;
FIG. 5 is the results of the measurement of specific surface area and pore size distribution of the 5.6nm interconnected hollow carbon nano-onion sample and the 5.6nm nitrogen-doped interconnected hollow carbon nano-onion sample of example 1;
FIG. 6 is an electrochemical test chart of 5.6nm interconnected hollow carbon nano-onion samples in example 1 in an aqueous three-electrode system, wherein a is a CV curve and b is a GCD curve;
FIG. 7 is an electrochemical test chart of 5.6nm nitrogen-doped interconnected hollow carbon nano onion samples in example 1 in an aqueous three-electrode system, wherein a is a CV curve and b is a GCD curve;
FIG. 8 is an electrochemical test graph of a symmetric supercapacitor device fabricated by using an ionic liquid electrolyte for a 5.6nm nitrogen-doped interconnected hollow carbon nano-onion sample in example 1, wherein a is a CV curve and b is a GCD curve;
FIG. 9 is a long cycle test plot of a symmetric supercapacitor device fabricated using ionic liquid electrolyte from 5.6nm nitrogen-doped interconnected hollow carbon nano-onion samples from example 1;
FIG. 10 is a Ragong plot of a symmetric supercapacitor device fabricated using ionic liquid electrolyte from a 5.6nm nitrogen-doped interconnected hollow carbon nano-onion sample from example 1;
FIG. 11 is a scanning electron microscope image of a 9.9nm interconnected hollow carbon nano-onion sample from example 2;
FIG. 12 is a TEM image of a 9.9nm interconnected hollow carbon nano-onion sample from example 2;
FIG. 13 is the results of the measurement of specific surface area and pore size distribution of 9.9nm interconnected hollow carbon nano-onions samples of example 2;
FIG. 14 is an electrochemical test chart of 9.9nm interconnected hollow carbon nano-onion samples in example 2 in an aqueous three-electrode system, wherein a is a CV curve and b is a GCD curve;
FIG. 15 is a scanning electron microscope image of a 12.6nm interconnected hollow carbon nano-onion sample from example 3;
FIG. 16 is a TEM image of a 12.6nm interconnected hollow carbon nano-onion sample from example 3;
FIG. 17 is the results of the measurement of the specific surface area and pore size distribution of the 12.6nm interconnected hollow carbon nano-onions sample in example 3;
FIG. 18 is an electrochemical test chart of a 12.6nm interconnected hollow carbon nano-onion sample in example 3 in an aqueous three-electrode system, wherein a is a CV curve and b is a GCD curve.
The specific implementation mode is as follows:
in order to make the technical solution of the present invention clearer and clearer, the present invention is further described below with reference to embodiments, and any solution obtained by performing equivalent replacement and conventional reasoning on the technical solution of the present invention belongs to the protection scope of the embodiments of the present invention.
Example 1:
preparation and performance test of 5.6nm nitrogen-doped interconnected hollow carbon nano onion super capacitor:
1)5.6nm Fe 3 O 4 and (3) nanoparticle synthesis:
mixing 5g of 1-octadecene and 0.356g of gamma-Fe 2 O 3 And 2.26g of oleic acid were placed in a three-necked flask and ultrasonically dispersed for 20 minutes, and then the three-necked flask was placed in a magnetic stirring heater. In N 2 Heating to 120 deg.C under atmosphere, and maintaining for 30min to remove water; then heating to 220 ℃ and preserving the heat for 30min to nucleate the nano particles; and finally, heating to 320 ℃ and preserving the temperature for 30min to enable the nucleated nanoparticles to grow. After cooling to room temperature, the resultant was centrifuged for the 1 st time with absolute ethanol to obtain Fe 3 O 4 Precipitating the nanoparticles; centrifuging for 2 and 3 times with mixed solution of n-hexane and anhydrous ethanol = 1: 3 to obtain Fe 3 O 4 Purifying the nanoparticles; finally diluting with n-hexane to obtain 5.6nm Fe 3 O 4 A dispersion of nanoparticles.
2) Preparation of 5.6nm interconnected hollow carbon nano-onions:
first, 5.6nm Fe 3 O 4 Drying the nano-particle dispersion liquid in a porcelain ark, heating to 500 ℃ in Ar atmosphere, and keeping the temperature for 1h; then, dispersing the sample in 6M HCl solution and stirring for 24 hours; and (3) after suction filtration and drying, heating to 1200 ℃ in Ar atmosphere, preserving heat for 2h, and cooling to room temperature to obtain the 5.6nm interconnected hollow carbon nano onion.
3) Preparation of 5.6nm nitrogen-doped interconnected hollow carbon nano-onions:
firstly, mixing 20mg of interconnected hollow carbon nano-onions with the diameter of 5.6nm and 60mg of urea, dispersing the mixture in 75% alcohol solution, carrying out ultrasonic treatment for 20min, and carrying out hydrothermal reaction for 24h at the temperature of 180 ℃; and after suction filtration and drying, heating to 900 ℃ in Ar atmosphere, preserving heat for 1h, and cooling to room temperature to obtain the 5.6nm nitrogen-doped interconnected hollow carbon nano onion.
4) Characterization of the materials:
the shape and structure of the material are characterized by using a scanning electron microscope, a transmission electron microscope and a BET specific surface area tester, and the analysis results are shown in figures 2-5, wherein the figures show the structure of the thin-layer hollow carbon nano onion with uniform size and interconnection and the distribution condition of N element in a carbon framework.
5) Preparation of electrodes and aqueous three-electrode testing:
the active material, carbon black and polyvinylidene fluoride were mixed in a ratio of 8: 1, stirred for 1 hour, and then an electrode was coated on a titanium foil in a thickness of 50 μm using a coater. And (3) putting the electrode into a vacuum drying oven, drying for 10 hours at the temperature of 80 ℃, and then heating to 120 ℃ for drying for 2 hours. 3M KOH solution is used as electrolyte, and the performance of the electrode is tested in a three-electrode test system, wherein the voltage window is-1-0V. Finally at 1 ag -1 At a current density of (A), the 5.6nm interconnected hollow carbon nano onion electrode was determined to have 183.4 Fg -1 The mass-to-capacitance of (1), wherein an electrochemical test chart is shown in FIG. 6; the 5.6nm nitrogen-doped interconnected hollow carbon nano onion electrode was measured to have 243.6 Fg -1 The mass to capacitance ratio of (1), wherein an electrochemical test chart is shown in fig. 7.
6) Assembling and testing the supercapacitor:
cutting the prepared electrode into 1 × 1cm 2 And the large sheet is used as a positive symmetrical electrode and a negative symmetrical electrode, and a diaphragm is inserted between the positive symmetrical electrode and the negative symmetrical electrode to package the supercapacitor. The method comprises the following specific steps: firstly, placing an electrode in a negative battery shell, respectively dropwise adding a small amount of electrolyte for wetting, then sequentially placing a glass fiber diaphragm, a positive electrode, a gasket, an elastic sheet and a positive battery shell which are soaked with the electrolyte, then placing the assembled symmetrical button type device into a mechanical packaging machine, and packaging under the pressure of 5Mpa to obtain the symmetrical supercapacitor, wherein the electrolyte is pure 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF 4) solution as the electrolyte to assemble the supercapacitor device. The assembled super capacitor device is 2kW kg -1 Has a power density of 168.9Wh kg -1 Even at 400kW kg -1 Still has 45.2Wh kg at the power density of -1 And a capacity retention rate of 98.2% after 50,000 cycles, has an excellent life span, wherein an electrochemical test chart, a long cycle test chart of a device, and a raleigh chart are shown in fig. 8 to 10.
Example 2:
preparation and performance test of 9.9nm interconnected hollow carbon nano onion electrode:
1)9.9nm Fe 3 O 4 and (3) synthesis of nanoparticles:
mixing 5g of 1-octadecene and 0.356g of gamma-Fe 2 O 3 And 3.39g of oleic acid were placed in a three-necked flask and ultrasonically dispersed for 20 minutes, and then the three-necked flask was placed in a magnetic stirring heater. In N 2 Heating to 120 deg.C in atmosphere, and maintaining for 30min to remove water in the medicine; then heating to 220 ℃ and preserving the heat for 40min to nucleate the nano particles; and finally, heating to 320 ℃ and preserving the temperature for 90min to enable the nucleated nanoparticles to grow. After cooling to room temperature, the resultant was centrifuged for the 1 st time with absolute ethanol to obtain Fe 3 O 4 Precipitating the nano particles; centrifuging for 2 nd and 3 rd times with mixed solution of n-hexane and anhydrous ethanol = 1: 3 to obtain Fe 3 O 4 Purifying the nanoparticles; finally diluting by using normal hexane to obtain 9.9nm Fe 3 O 4 A dispersion of nanoparticles.
2) Preparation of 9.9nm interconnected hollow carbon nano-onions:
first, 9.9nm F e 3O 4 Drying the nano-particle dispersion liquid in a porcelain ark, heating to 500 ℃ in Ar atmosphere, and keeping the temperature for 1h; then, dispersing the sample in 6M HCl solution and stirring for 24 hours; and (3) after suction filtration and drying, heating to 1200 ℃ in Ar atmosphere, preserving the heat for 2h, and cooling to room temperature to obtain 9.9nm interconnected hollow carbon nano-onion.
3) Characterization of the materials:
the material was characterized by morphology and structure using a scanning electron microscope, a transmission electron microscope and a BET specific surface area tester, and the analysis results are shown in fig. 11 to 13, which show the structure of thin-layer hollow carbon nano onions with uniform size and interconnection.
4) Preparation of electrodes and aqueous three-electrode testing:
the active material, carbon black and polyvinylidene fluoride were mixed in a ratio of 8: 1, stirred for 1 hour, and then an electrode was coated on a titanium foil in a thickness of 50 μm using a coater. And (3) putting the electrode into a vacuum drying oven, drying for 10 hours at the temperature of 80 ℃, and then heating to 120 ℃ for drying for 2 hours. 3M KOH solution is used as electrolyte, and the performance of the electrode is tested in a three-electrode test system, wherein the voltage window is-1-0V. Finally at 1 Ag -1 At a current density of (A), the 9.9nm interconnected hollow carbon nano onion electrode was measured to have 76.7 Fg -1 The mass-to-capacitance of (1), wherein an electrochemical test chart is shown in fig. 14.
Example 3:
1) Preparation and performance test of a 12.6nm interconnected hollow carbon nano onion electrode:
1)12.6nm Fe 3 O 4 and (3) synthesis of nanoparticles:
mixing 5g of 1-octadecene and 0.356g of gamma-Fe 2 O 3 And 4.52g of oleic acid were placed in a three-necked flask and ultrasonically dispersed for 20 minutes, and then the three-necked flask was placed in a magnetic stirring heater. In N 2 Heating to 120 deg.C under atmosphere, and maintaining for 30min to remove water; then heating to 220 ℃ and preserving the heat for 40min to nucleate the nano particles; and finally, heating to 320 ℃ and preserving the temperature for 180min to enable the nucleated nanoparticles to grow. After cooling to room temperature, the 1 st centrifugation was performed using absolute ethanol to remove Fe 3 O 4 Precipitating the nano particles; centrifuging for 2 nd and 3 rd times with mixed solution of n-hexane and anhydrous ethanol = 1: 3 to obtain Fe 3 O 4 Purifying the nanoparticles; finally diluting with n-hexane to obtain 12.6nm Fe 3 O 4 A dispersion of nanoparticles.
2) Preparation of 12.6nm interconnected hollow carbon nano-onions:
first, 12.6nm Fe 3 O 4 Placing the nano-particle dispersion liquid in a porcelain ark, drying, heating to 500 ℃ in Ar atmosphere, and keeping the temperature for 1h; then, dispersing the sample in 6M HCl solution and stirring for 24 hours; and (3) after suction filtration and drying, heating to 1200 ℃ in Ar atmosphere, preserving the heat for 2h, and cooling to room temperature to obtain the interconnected hollow carbon nano onion with the particle size of 12.6 nm.
3) Characterization of the materials:
the shape and structure of the sample are characterized by using a scanning electron microscope, a transmission electron microscope and a BET specific surface area tester, and the analysis result is shown in FIGS. 15-17, which show the structure of the thin-layer hollow carbon nano onion with uniform size and interconnection.
4) Preparation of electrodes and aqueous three-electrode test:
the active material, carbon black and polyvinylidene fluoride were mixed at a ratio of 8: 1, stirred for 1 hour, and then an electrode was coated on a titanium foil at a thickness of 50 μm using a coater. And (3) putting the electrode into a vacuum drying oven, drying for 10 hours at the temperature of 80 ℃, and then heating to 120 ℃ for drying for 2 hours. 3M KOH solution is used as electrolyte, and the performance of the electrode is tested in a three-electrode test system, wherein the voltage window is-1-0V. Finally at 1 ag -1 At a current density of (A), the 12.6nm interconnected hollow carbon nano onion-based electrode was measured to have a mass of 56.8F g -1 The mass-to-capacitance of (1), wherein an electrochemical test chart is shown in fig. 18.

Claims (7)

1. The nitrogen-doped interconnected hollow carbon nano onion structure with high energy density and high power density is characterized in that the preparation method comprises the following steps:
1)Fe 3 O 4 preparing a nano-particle template: firstly, fe is mixed according to a specific proportion 2 O 3 Mixing and stirring oleic acid and 1-octadecylene in inert gas or vacuum, carrying out heat preservation reaction on the mixed solution at the temperature of 100-340 ℃, and finally synthesizing monodisperse uniform-size Fe with the surface modified with oleic acid ligand 3 O 4 Cooling the nano particles to room temperature, and purifying and diluting the nano particles by using a non-polar organic solvent to obtain Fe 3 O 4 A dispersion of nanoparticles.
2) Carbonizing: mixing Fe 3 O 4 Drying the nanoparticle dispersion liquid in a container, heating to a certain temperature in inert gas or vacuum, keeping the temperature, and cooling to room temperature to obtain the coated Fe 3 O 4 Interconnected carbon structures of nanoparticles.
3) And (3) purification: removal of Fe by acid solution 3 O 4 And washing and drying the nano particles to obtain the interconnected hollow carbon structure.
4) Graphitizing: and (3) placing the interconnected hollow carbon structure in inert gas or vacuum, heating to a certain temperature, carrying out heat preservation graphitization treatment, and cooling to room temperature to obtain the interconnected hollow carbon nano onion structure.
5) Nitrogen doping: and (2) mixing the interconnected hollow carbon nano onion and urea according to a certain proportion, grinding, dispersing in a solvent for hydrothermal reaction, washing and drying a sample after the reaction is finished, and then placing the sample in inert gas or vacuum for high-temperature annealing treatment to obtain the nitrogen-doped interconnected hollow carbon nano onion structure.
6) Preparing an electrode and assembling a super capacitor: and coating the electrode material on a current collector, and drying to obtain the nitrogen-doped interconnected hollow carbon nano onion electrode. And taking the electrode as a positive symmetrical electrode and a negative symmetrical electrode, inserting a diaphragm in the middle, and packaging the super capacitor to obtain the super capacitor device.
2. The nitrogen-doped interconnected hollow carbon nano-onions with both high energy density and high power density of claim 1, wherein the metal oxide template is not limited to Fe 3 O 4 Other commonly used metal oxides are also included such as: alumina, nickel oxide, cobalt oxide, and the like; the surface ligand is not limited to oleic acid, but also includes other commonly used organic ligands such as oleylamine, dodecanethiol, and the like; the solvent is not limited to 1-octadecene, but also includes other high boiling organic solvents such as dibenzyl ether, tetracosanol, etc.
3. The nitrogen-doped interconnected hollow carbon nano-onions having both high energy density and high power density as claimed in claim 1, wherein the carbonization step is carried out by keeping the temperature in an inert gas or vacuum for a period of time within a temperature range of 300-700 ℃.
4. The nitrogen-doped interconnected hollow carbon nano-onions with both high energy density and high power density as claimed in claim 1, wherein the acid solution used in the purification stage comprises common acid solutions such as hydrochloric acid, nitric acid, sulfuric acid, etc.
5. The nitrogen-doped interconnected hollow carbon nano-onions having both high energy density and high power density as claimed in claim 1, wherein the graphitization stage is by holding in an inert gas or vacuum for a period of time at a temperature in the range of 800-1400 ℃.
6. The nitrogen-doped interconnected hollow carbon nano-onions with both high energy density and high power density as claimed in claim 1, wherein the solvent used in the hydrothermal process comprises water, absolute ethyl alcohol, a mixture of water and ethyl alcohol, and the like.
7. The nitrogen-doped interconnected hollow carbon nano-onions with both high energy density and high power density as claimed in claim 1, wherein the high temperature annealing treatment in the nitrogen doping stage is carried out by holding the onions in an inert gas or vacuum for a period of time within a temperature range of 600-1200 ℃.
CN202210188862.6A 2022-03-01 2022-03-01 Preparation of nitrogen-doped interconnected hollow carbon nano onion structure with high energy density and high power density Pending CN115188601A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210188862.6A CN115188601A (en) 2022-03-01 2022-03-01 Preparation of nitrogen-doped interconnected hollow carbon nano onion structure with high energy density and high power density

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210188862.6A CN115188601A (en) 2022-03-01 2022-03-01 Preparation of nitrogen-doped interconnected hollow carbon nano onion structure with high energy density and high power density

Publications (1)

Publication Number Publication Date
CN115188601A true CN115188601A (en) 2022-10-14

Family

ID=83511603

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210188862.6A Pending CN115188601A (en) 2022-03-01 2022-03-01 Preparation of nitrogen-doped interconnected hollow carbon nano onion structure with high energy density and high power density

Country Status (1)

Country Link
CN (1) CN115188601A (en)

Similar Documents

Publication Publication Date Title
Han et al. Enhancing the capacitive storage performance of carbon fiber textile by surface and structural modulation for advanced flexible asymmetric supercapacitors
Lu et al. Nitrogen-containing ultramicroporous carbon nanospheres for high performance supercapacitor electrodes
Yu et al. Mesoporous NiCo2O4 nanoneedles grown on 3D graphene-nickel foam for supercapacitor and methanol electro-oxidation
Ruibin et al. Monodisperse carbon microspheres derived from potato starch for asymmetric supercapacitors
US7553341B2 (en) High power density supercapacitors with carbon nanotube electrodes
CN102941042B (en) A kind of Graphene/metal oxide hybrid aeroge, preparation method and application thereof
Pang et al. Mesoporous NiCo 2 O 4 nanospheres with a high specific surface area as electrode materials for high-performance supercapacitors
Guan et al. Core/shell nanorods of MnO2/carbon embedded with Ag nanoparticles as high-performance electrode materials for supercapacitors
CN108630920A (en) A kind of nano-metal-oxide/MXene heterojunction structure composite material and preparation methods
Li et al. Transition metal doped MnO2 nanosheets grown on internal surface of macroporous carbon for supercapacitors and oxygen reduction reaction electrocatalysts
KR101728720B1 (en) Graphene composite comprising three dimensional carbon nanotube pillars and method of fabricating thereof
Shi et al. Low temperature synthesis of polyhedral hollow porous carbon with high rate capability and long-term cycling stability as Li-ion and Na-ion battery anode material
Xu et al. Facile hydrothermal synthesis of tubular kapok fiber/MnO 2 composites and application in supercapacitors
CN108198701B (en) Cobaltosic oxide/carbon composite electrode material, preparation method and application thereof
CN111785956B (en) Flexible electrode material for lithium ion battery and preparation method thereof
Li et al. Low Li ion diffusion barrier on low-crystalline FeOOH nanosheets and high performance of energy storage
CN111689523B (en) Metallic chromium doped delta-MnO2Preparation method of nanosheet
Liu et al. Effect of soft template on NiMn-LDH grown on nickel foam for battery-type electrode materials
CN109449009B (en) One-dimensional manganese dioxide nanotube @ ZIF-67 core-shell heterostructure composite material and preparation method and application thereof
Yang et al. Preparation of super thin and defect rich graphene shell and its application for high performance supercapacitor electrode and novel ORR catalyst support
Yan et al. Hierarchical MnO2@ NiCo2O4@ Ti3SiC2/carbon cloth core-shell structure with superior electrochemical performance for all solid-state supercapacitors
CN109192522B (en) Fe2O3Nano carbon tube composite material, preparation method thereof and super capacitor
CN116812969A (en) Preparation method of hierarchical pore indium oxide nanotube for lithium ion battery cathode
CN113470982B (en) High-performance flexible supercapacitor composite electrode material and preparation method thereof
CN115188601A (en) Preparation of nitrogen-doped interconnected hollow carbon nano onion structure with high energy density and high power density

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination