CN111161961A - Carbon dot/porous carbon composite electrode material for super capacitor and preparation method thereof - Google Patents
Carbon dot/porous carbon composite electrode material for super capacitor and preparation method thereof Download PDFInfo
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 143
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 143
- 239000007772 electrode material Substances 0.000 title claims abstract description 69
- 239000002131 composite material Substances 0.000 title claims abstract description 64
- 238000002360 preparation method Methods 0.000 title claims abstract description 25
- 239000003990 capacitor Substances 0.000 title claims abstract description 15
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 50
- 238000004227 thermal cracking Methods 0.000 claims abstract description 48
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 claims abstract description 30
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims abstract description 28
- 239000007864 aqueous solution Substances 0.000 claims abstract description 28
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 24
- 229920002239 polyacrylonitrile Polymers 0.000 claims abstract description 18
- 239000005543 nano-size silicon particle Substances 0.000 claims abstract description 16
- 235000005074 zinc chloride Nutrition 0.000 claims abstract description 15
- 239000011592 zinc chloride Substances 0.000 claims abstract description 15
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 10
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims abstract description 8
- 235000014692 zinc oxide Nutrition 0.000 claims abstract description 8
- 239000011787 zinc oxide Substances 0.000 claims abstract description 8
- 229960001296 zinc oxide Drugs 0.000 claims abstract description 8
- XLOMVQKBTHCTTD-UHFFFAOYSA-N zinc oxide Inorganic materials [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims abstract description 8
- 238000000034 method Methods 0.000 claims abstract description 6
- 239000011261 inert gas Substances 0.000 claims abstract description 3
- 238000010438 heat treatment Methods 0.000 claims description 8
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 8
- 238000002791 soaking Methods 0.000 claims description 8
- 238000006116 polymerization reaction Methods 0.000 claims description 3
- 238000005336 cracking Methods 0.000 claims description 2
- 238000001035 drying Methods 0.000 claims description 2
- 238000007710 freezing Methods 0.000 claims description 2
- 230000008014 freezing Effects 0.000 claims description 2
- 125000004433 nitrogen atom Chemical group N* 0.000 claims description 2
- 238000004108 freeze drying Methods 0.000 abstract description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 24
- 229910052757 nitrogen Inorganic materials 0.000 description 12
- 125000004122 cyclic group Chemical group 0.000 description 10
- 230000014759 maintenance of location Effects 0.000 description 10
- 239000000047 product Substances 0.000 description 8
- 239000000243 solution Substances 0.000 description 6
- IMQLKJBTEOYOSI-GPIVLXJGSA-N Inositol-hexakisphosphate Chemical compound OP(O)(=O)O[C@H]1[C@H](OP(O)(O)=O)[C@@H](OP(O)(O)=O)[C@H](OP(O)(O)=O)[C@H](OP(O)(O)=O)[C@@H]1OP(O)(O)=O IMQLKJBTEOYOSI-GPIVLXJGSA-N 0.000 description 5
- IMQLKJBTEOYOSI-UHFFFAOYSA-N Phytic acid Natural products OP(O)(=O)OC1C(OP(O)(O)=O)C(OP(O)(O)=O)C(OP(O)(O)=O)C(OP(O)(O)=O)C1OP(O)(O)=O IMQLKJBTEOYOSI-UHFFFAOYSA-N 0.000 description 5
- 229920002873 Polyethylenimine Polymers 0.000 description 5
- 239000008367 deionised water Substances 0.000 description 5
- 229910021641 deionized water Inorganic materials 0.000 description 5
- 238000001027 hydrothermal synthesis Methods 0.000 description 5
- 229940068041 phytic acid Drugs 0.000 description 5
- 235000002949 phytic acid Nutrition 0.000 description 5
- 239000000467 phytic acid Substances 0.000 description 5
- 239000006228 supernatant Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 238000002484 cyclic voltammetry Methods 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 238000000026 X-ray photoelectron spectrum Methods 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000012983 electrochemical energy storage Methods 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000015654 memory Effects 0.000 description 2
- 238000001000 micrograph Methods 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- 238000003917 TEM image Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 230000001413 cellular effect Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052987 metal hydride Inorganic materials 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-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
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-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
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Abstract
The invention provides a carbon dot/porous carbon composite electrode material for a super capacitor and a preparation method thereof, wherein the method comprises the following steps: s1, dissolving zinc chloride into the carbon dot aqueous solution, and adding polyacrylonitrile and nano silicon dioxide to form sol; s2, carrying out thermal cracking on the sol under the protection of inert gas after freeze drying; and S3, immersing the product obtained by thermal cracking in hydrofluoric acid to remove zinc and silicon dioxide to obtain the carbon dot/porous carbon composite electrode material. The preparation method provided by the invention has the advantages of simple process, low cost and easy industrial popularization; when the prepared carbon dot/porous carbon composite electrode material is used for a supercapacitor electrode material, the prepared carbon dot/porous carbon composite electrode material has high specific capacitance value, excellent rate capability and good cycle stability.
Description
Technical Field
The invention relates to the technical field of electrochemical energy storage electrode material preparation, in particular to a carbon dot/porous carbon composite electrode material for a super capacitor and a preparation method thereof.
Background
The super capacitor, as a novel energy storage device between the traditional capacitor and the rechargeable battery, has the advantages of high energy density, high power, long service life and the like, and arouses the wide interest of researchers of electrochemical energy storage devices at home and abroad. The super capacitor has the characteristics of low production cost, small environmental pollution, high safety and the like, and has great practical application value in various fields such as new energy automobiles, portable electronic equipment, memory memories, aviation and military and the like, and the electrode material plays a decisive role in the performance of the super capacitor.
Porous carbon has the advantages of large specific surface area, high conductivity, abundant pore-size structures and the like, and is currently used as an electrode material of a commercial supercapacitor. At present, the energy density of commercial super capacitors developed at home and abroad by taking porous carbon as an electrode material is higher than that of traditional batteries (for example, 35-45 Wh kg of lead-acid batteries-150-80 Wh kg of nickel-metal hydride battery-1170-200 Wh kg of lithium ion battery-1) Still much smaller. The low energy density results in a high price of energy per watt hour, which is not conducive to large-scale energy storage applications. Therefore, it is very important to increase the specific capacity of the porous carbon material to increase the energy density of the supercapacitor.
Disclosure of Invention
In order to solve the technical problems, the invention provides a preparation method of a carbon dot/porous carbon composite electrode material for a supercapacitor, which comprises the following steps:
s1: dissolving zinc chloride into a carbon dot aqueous solution, and adding polyacrylonitrile and nano-silica to form sol;
s2: freezing and drying the sol prepared in the step S1, and then thermally cracking under the protection of inert gas;
s3: and (4) immersing the product obtained by the thermal cracking in the step S2 in hydrofluoric acid to remove zinc and silicon dioxide to obtain the carbon dot/porous carbon composite electrode material.
Wherein the mass concentration of carbon dots in the carbon dot aqueous solution is 1-5 g/L.
Preferably, the mass concentration of carbon dots in the carbon dot aqueous solution is 1.5 g/L, 2 g/L, 2.5 g/L, 3 g/L, 3.5 g/L, 4 g/L and 4.5 g/L.
The mass ratio of the zinc chloride to the carbon dot aqueous solution to the polyacrylonitrile to the nano silicon dioxide is 100-25: 1-20: 2-10: 1-5.
Wherein the thermal crackingThe temperature of the heating medium is 700-900 ℃, and the heating rate is 1-5oC/min。
Preferably, the thermal cracking temperature is 750 ℃, 800 ℃, 850 ℃.
Wherein the thermal cracking time is 1-6 h.
Preferably, the thermal cracking time is 2h, 2.5h, 3 h, 3.5 h, 4h, 4.5 h, 5h, 5.5 h.
Wherein the concentration of the hydrofluoric acid is 15-40 wt%.
Preferably, the concentration of the hydrofluoric acid is 20wt%, 25wt%, 30wt%, 35 wt%.
Wherein, the time of soaking the product obtained by thermal cracking in hydrofluoric acid is 8-24 h.
Preferably, the time for soaking the product obtained by thermal cracking in hydrofluoric acid is 10h, 12h, 14 h, 16 h, 18h, 20h and 22 h.
Wherein the polymerization degree of the polyacrylonitrile is greater than or equal to 2500.
Wherein the size of the nano silicon dioxide is 5-50 nm.
The second aspect of the invention provides a carbon dot/porous carbon composite electrode material for a supercapacitor, wherein the carbon dot/porous carbon composite electrode material is prepared according to the preparation method provided by the first aspect of the invention, and the content of doped nitrogen atoms in the carbon dot/porous carbon composite electrode material is 4-9 at%.
The invention has the beneficial effects that:
the preparation method of the carbon dot/porous carbon composite electrode material provided by the invention has the advantages of simple process, low cost and easy industrial popularization. When the prepared carbon dot/porous carbon composite electrode material is used as a supercapacitor electrode material, the surface roughness of the carbon dot/porous carbon composite electrode material is 1Ag-1Has a specific capacitance of up to 344F g at a current density of-1The capacity retention rate after 40000 times of cyclic charge and discharge is 101.2%; at high current density 50A g-1The specific capacitance is still as high as 305F g-1The high-capacitance-ratio-based high-capacitance-ratio.
Drawings
In order to more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it should be obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a scanning electron microscope image of a carbon dot/porous carbon composite electrode material prepared in example 1 of the present invention;
FIG. 2 is a transmission electron microscope image of the carbon dot/porous carbon composite electrode material prepared in example 1 of the present invention;
FIG. 3 is an X-ray photoelectron spectrum of the carbon dot/porous carbon composite electrode material prepared in example 1 of the present invention;
FIG. 4 is a cyclic voltammogram of the carbon dot/porous carbon composite electrode material prepared in example 1 of the present invention;
fig. 5 is a charge-discharge curve diagram of the carbon dot/porous carbon composite electrode material prepared in example 1 of the present invention.
Detailed Description
The following is a preferred embodiment of the present invention, and it should be noted that it is obvious to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements are also considered to be within the scope of the present invention.
Example 1
The invention provides a preparation method of a carbon dot/porous carbon composite electrode material for a super capacitor, which comprises the following steps:
s1: dispersing 2.76 g of phytic acid and 1.53 g of polyethyleneimine into 18 mL of deionized water, carrying out hydrothermal reaction for 5h at the temperature of 160 ℃, centrifuging the obtained black solution at a high speed for 30 min, taking supernatant, and fixing the volume in 100 mL of aqueous solution to obtain the carbon dot aqueous solution with the mass concentration of carbon dots of 2.5 g/L;
s2: dissolving zinc chloride into the carbon dot aqueous solution prepared in the step S1, and then adding polyacrylonitrile and nano silicon dioxide to form sol; wherein the mass ratio of the zinc chloride to the carbon dot aqueous solution to the polyacrylonitrile to the nano silicon dioxide is 25:16:2: 1;
s3: freeze-drying the sol prepared in the step S2, and then carrying out thermal cracking under the protection of nitrogen, wherein the thermal cracking temperature is 900 ℃, the thermal cracking time is 1h, and the heating rate of thermal cracking is 3 ℃/min;
s4: and (4) soaking the product obtained by the thermal cracking in the step S3 in hydrofluoric acid with the concentration of 30wt% for 12h, and removing zinc and silicon dioxide to obtain the carbon dot/porous carbon composite electrode material.
The nitrogen content of the carbon dot/porous carbon composite electrode material prepared in example 1 is 6%, which is 1A g-1Has a specific capacitance of 344F g-1The capacity retention rate after 40000 times of cyclic charge and discharge is 101.2%, and the high current density is 50A g-1The specific capacitance is still as high as 305F g-1。
Fig. 1 is a scanning electron micrograph of the carbon dot/porous carbon composite electrode material prepared in example 1, and it can be seen from fig. 1 that: the material exhibits a cellular porous structure.
Fig. 2 is a transmission electron micrograph of the carbon dot/porous carbon composite electrode material prepared in example 1, and it can be seen from fig. 1 that: the material is an amorphous porous structure.
Fig. 3 is an X-ray photoelectron spectrum of the carbon dot/porous carbon composite electrode material prepared in example 1, from which it can be seen that: the composite material is rich in N element doping.
Fig. 4 is a cyclic voltammogram of the carbon dot/porous carbon composite electrode material prepared in example 1, and it can be seen from fig. 1 that: as the sweep rate is increased, the cyclic voltammogram of the composite electrode material is basically not deformed, and the composite electrode material has ideal capacitance and rate property.
Fig. 5 is a charge-discharge curve diagram of the carbon dot/porous carbon composite electrode material prepared in example 1, and it can be seen from fig. 1 that: as the sweep rate is increased, the cyclic voltammogram of the composite electrode material is basically not deformed, and the composite electrode material has ideal capacitance and rate property.
Example 2
The invention provides a preparation method of a carbon dot/porous carbon composite electrode material for a super capacitor, which comprises the following steps:
s1: dispersing 0.92 g of phytic acid and 0.51 g of polyethyleneimine in 6 mL of deionized water, carrying out hydrothermal reaction for 5h at the temperature of 160 ℃, centrifuging the obtained black solution at a high speed for 30 min, taking supernatant, and fixing the volume in 100 mL of aqueous solution to obtain the carbon dot aqueous solution with the mass concentration of carbon dots of 1 g/L;
s2: dissolving zinc chloride into the carbon dot aqueous solution prepared in the step S1, and then adding polyacrylonitrile and nano silicon dioxide to form sol; wherein the mass ratio of the zinc chloride to the carbon dot aqueous solution to the polyacrylonitrile to the nano silicon dioxide is 25:20:2: 1;
s3: freeze-drying the sol prepared in the step S2, and then carrying out thermal cracking under the protection of nitrogen, wherein the thermal cracking temperature is 900 ℃, the thermal cracking time is 1h, and the heating rate of thermal cracking is 3 ℃/min;
s4: and (4) soaking the product obtained by the thermal cracking in the step S3 in hydrofluoric acid with the concentration of 30wt% for 12h, and removing zinc and silicon dioxide to obtain the carbon dot/porous carbon composite electrode material.
The nitrogen content of the carbon dot/porous carbon composite electrode material prepared in the example 2 is 6.8 percent and is 1A g-1At a current density of up to 325F g-1The capacity retention rate after 40000 times of cyclic charge and discharge is 100.5%, and the high current density is 50A g-1The specific capacitance is still as high as 295F g-1。
Example 3
The invention provides a preparation method of a carbon dot/porous carbon composite electrode material for a super capacitor, which comprises the following steps:
s1: dispersing 2.76 g of phytic acid and 1.53 g of polyethyleneimine into 18 mL of deionized water, carrying out hydrothermal reaction for 5h at the temperature of 160 ℃, centrifuging the obtained black solution at a high speed for 30 min, taking supernatant, and fixing the volume in 100 mL of aqueous solution to obtain the carbon dot aqueous solution with the mass concentration of carbon dots of 2.5 g/L;
s2: dissolving zinc chloride into the carbon dot aqueous solution prepared in the step S1, and then adding polyacrylonitrile and nano silicon dioxide to form sol; wherein the mass ratio of the zinc chloride to the carbon dot aqueous solution to the polyacrylonitrile to the nano silicon dioxide is 50:10:5: 2;
s3: freeze-drying the sol prepared in the step S2, and then carrying out thermal cracking under the protection of nitrogen, wherein the thermal cracking temperature is 800 ℃, the thermal cracking time is 4 hours, and the heating rate of the thermal cracking is 2 ℃/min;
s4: and (4) soaking the product obtained by the thermal cracking in the step S3 in hydrofluoric acid with the concentration of 20wt% for 20h, and removing zinc and silicon dioxide to obtain the carbon dot/porous carbon composite electrode material.
The nitrogen content of the carbon dot/porous carbon composite electrode material prepared in example 3 is 5.6%, which is 1A g%-1Has a specific capacitance of up to 315F g-1The capacity retention rate after 40000 times of cyclic charge and discharge is 99.6%, and the high current density is 50A g-1The specific capacitance is still as high as 270F g-1。
Example 4
The invention provides a preparation method of a carbon dot/porous carbon composite electrode material for a super capacitor, which comprises the following steps:
s1: dispersing 2.76 g of phytic acid and 1.53 g of polyethyleneimine into 18 mL of deionized water, carrying out hydrothermal reaction for 5h at the temperature of 160 ℃, centrifuging the obtained black solution at a high speed for 30 min, taking supernatant, and fixing the volume in 100 mL of aqueous solution to obtain the carbon dot aqueous solution with the mass concentration of carbon dots of 2.5 g/L;
s2: dissolving zinc chloride into the carbon dot aqueous solution prepared in the step S1, and then adding polyacrylonitrile and nano silicon dioxide to form sol; wherein the mass ratio of the zinc chloride to the carbon dot aqueous solution to the polyacrylonitrile to the nano silicon dioxide is 75:10:5: 1;
s3: freeze-drying the sol prepared in the step S2, and then carrying out thermal cracking under the protection of argon, wherein the thermal cracking temperature is 750 ℃, the thermal cracking time is 4h, and the heating rate of thermal cracking is 4 ℃/min;
s4: and (4) soaking the product obtained by the thermal cracking in the step S3 in 35wt% hydrofluoric acid for 10h, and removing zinc and silicon dioxide to obtain the carbon dot/porous carbon composite electrode material.
The nitrogen content of the carbon dot/porous carbon composite electrode material prepared in the example 4 is 8.3 percent and is 1A g-1Has a specific capacitance of up to 310F g-1The capacity retention rate after 40000 times of cyclic charge and discharge is 88 percent, and the high current density is 50 Ag-1The specific capacitance is still as high as 230F g-1。
Example 5
The invention provides a preparation method of a carbon dot/porous carbon composite electrode material for a super capacitor, which comprises the following steps:
s1: dispersing 2.76 g of phytic acid and 1.53 g of polyethyleneimine into 18 mL of deionized water, carrying out hydrothermal reaction for 5h at the temperature of 160 ℃, centrifuging the obtained black solution at a high speed for 30 min, taking supernatant, and fixing the volume in 100 mL of aqueous solution to obtain the carbon dot aqueous solution with the mass concentration of carbon dots of 2.5 g/L;
s2: dissolving zinc chloride into the carbon dot aqueous solution prepared in the step S1, and then adding polyacrylonitrile and nano silicon dioxide to form sol; wherein the mass ratio of the zinc chloride to the carbon dot aqueous solution to the polyacrylonitrile to the nano silicon dioxide is 50:15:5: 5;
s3: freeze-drying the sol prepared in the step S2, and then carrying out thermal cracking under the protection of argon, wherein the thermal cracking temperature is 850 ℃, the thermal cracking time is 2h, and the heating rate of thermal cracking is 5 ℃/min;
s4: and (4) soaking the product obtained by the thermal cracking in the step S3 in hydrofluoric acid with the concentration of 25 omega t% for 15 hours, and removing zinc and silicon dioxide to obtain the carbon dot/porous carbon composite electrode material.
The nitrogen content of the carbon dot/porous carbon composite electrode material prepared in example 5 is 4.3%, which is 1A g%-1Has a specific capacitance of up to 315F g-1The capacity retention rate after 40000 times of cyclic charge and discharge is 90 percent, and the high current density is 50 Ag-1The specific capacitance is still as high as 265F g-1。
In order to verify the influence of the thermal cracking temperature on the performance of the prepared carbon dot/porous carbon composite electrode material in the preparation method provided by the invention, the following example 1 is taken as a reference, other process parameters are controlled to be unchanged, and a first set of comparative tests are set by changing the thermal cracking temperature, as shown in table 1.
As can be seen from the data in table 1: when the thermal cracking temperature reaches 800 ℃, the nitrogen content of the prepared carbon dot/porous carbon composite electrode material is 8.6 percent and is 1A g-1Has a specific capacitance of up to 312F g-1The capacity retention rate after 40000 times of cyclic charge and discharge is 95.3%, and the high current density is 50A g-1The specific capacitance is still as high as 222F g-1(ii) a When the thermal cracking temperature reaches 900 ℃, the nitrogen content of the prepared carbon dot/porous carbon composite electrode material is 6.0 percent and is 1A g percent-1Has a specific capacitance of 344F g-1The capacity retention rate after 40000 times of cyclic charge and discharge is 101.2%, and the high current density is 50A g-1The specific capacitance is still as high as 305F g-1. Therefore, the thermal cracking temperature is preferably 800 to 900 ℃.
In order to verify the influence of the thermal cracking time on the performance of the prepared carbon dot/porous carbon composite electrode material in the preparation method provided by the invention, the following example 1 is taken as a reference, other process parameters are controlled to be unchanged, and a second set of comparative tests are set by changing the thermal cracking time, as shown in table 2.
As can be seen from the data in table 2: when the thermal cracking time is 1h, the nitrogen content of the prepared carbon dot/porous carbon composite electrode material is 6 percent and is 1A g-1Has a specific capacitance of 344F g-1The capacity retention rate after 40000 times of cyclic charge and discharge is 101.2%, and the high current density is 50A g-1The specific capacitance is still as high as 305F g-1(ii) a When the thermal cracking time is 2 hours, the nitrogen content of the prepared carbon dot/porous carbon composite electrode material can be reduced to4.5% at 1A g-1Has a specific capacitance of up to 313F g-1The capacity retention rate after 40000 times of cyclic charge and discharge is 100.3%, and the high current density is 50A g-1The specific capacitance is still as high as 280F g-1. Therefore, when the thermal cracking temperature is 900 ℃, the thermal cracking time is preferably 1-2 h.
The polymerization degree of the polyacrylonitrile adopted in the embodiment of the invention is 2500, and the size of the nano silicon dioxide is 5-50 nm.
The above examples only express the specific embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the spirit of the present invention, and these changes and modifications are all within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A preparation method of a carbon dot/porous carbon composite electrode material for a super capacitor is characterized by comprising the following steps:
s1: dissolving zinc chloride into a carbon dot aqueous solution, and adding polyacrylonitrile and nano-silica to form sol;
s2: freezing and drying the sol prepared in the step S1, and then thermally cracking under the protection of inert gas;
s3: and (4) immersing the product obtained by the thermal cracking in the step S2 in hydrofluoric acid to remove zinc and silicon dioxide to obtain the carbon dot/porous carbon composite electrode material.
2. The preparation method of the carbon dot/porous carbon composite electrode material for the supercapacitor according to claim 1, characterized by comprising the following steps: the mass concentration of carbon dots in the carbon dot aqueous solution is 1-5 g/L.
3. The preparation method of the carbon dot/porous carbon composite electrode material for the supercapacitor according to claim 2, characterized by comprising the following steps: the mass ratio of the zinc chloride to the carbon dot aqueous solution to the polyacrylonitrile to the nano silicon dioxide is 100-25: 1-20: 2-10: 1-5.
4. The preparation method of the carbon dot/porous carbon composite electrode material for the supercapacitor according to any one of claims 1 to 3, characterized by comprising the following steps: the thermal cracking temperature is 700-900 ℃, and the heating rate is 1-5 oC/min.
5. The preparation method of the carbon dot/porous carbon composite electrode material for the supercapacitor according to any one of claims 1 to 3, characterized by comprising the following steps: the thermal cracking time is 1-6 h.
6. The preparation method of the carbon dot/porous carbon composite electrode material for the supercapacitor according to any one of claims 1 to 3, characterized by comprising the following steps: the concentration of the hydrofluoric acid is 15-40 wt%.
7. The preparation method of the carbon dot/porous carbon composite electrode material for the supercapacitor according to any one of claims 1 to 3, characterized by comprising the following steps: the time for soaking the product obtained by thermal cracking in hydrofluoric acid is 8-24 h.
8. The preparation method of the carbon dot/porous carbon composite electrode material for the supercapacitor according to any one of claims 1 to 3, characterized by comprising the following steps: the polymerization degree of the polyacrylonitrile is larger than or equal to 2500.
9. The preparation method of the carbon dot/porous carbon composite electrode material for the supercapacitor according to any one of claims 1 to 3, characterized by comprising the following steps: the size of the nano silicon dioxide is 5-50 nm.
10. A carbon dot/porous carbon composite electrode material for a supercapacitor is characterized in that: the carbon dot/porous carbon composite electrode material is prepared by the method provided by any one of claims 1 to 9, and the content of doped nitrogen atoms in the carbon dot/porous carbon composite electrode material is 4-9 at%.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160164019A1 (en) * | 2014-11-14 | 2016-06-09 | Louisiana State University Board of Supervisiors | Carbon Dot Light Emitting Diodes |
| CN106887344A (en) * | 2017-02-06 | 2017-06-23 | 清华大学 | Electrode of super capacitor and preparation method thereof and ultracapacitor |
| CN109675601A (en) * | 2018-12-24 | 2019-04-26 | 南昌航空大学 | A kind of preparation method without the porous carbon cathode material of metal-N doping for electrocatalytic oxidation reducing catalyst |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160164019A1 (en) * | 2014-11-14 | 2016-06-09 | Louisiana State University Board of Supervisiors | Carbon Dot Light Emitting Diodes |
| CN106887344A (en) * | 2017-02-06 | 2017-06-23 | 清华大学 | Electrode of super capacitor and preparation method thereof and ultracapacitor |
| CN109675601A (en) * | 2018-12-24 | 2019-04-26 | 南昌航空大学 | A kind of preparation method without the porous carbon cathode material of metal-N doping for electrocatalytic oxidation reducing catalyst |
Non-Patent Citations (1)
| Title |
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| LINGXIAO LV: "Three-dimensional multichannel aerogel of carbon quantum dots for high-performance supercapacitors", 《NANOTECHNOLOGY》 * |
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