CN110970224A - Nickel hydroxide/graphite composite material - Google Patents
Nickel hydroxide/graphite composite material Download PDFInfo
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- CN110970224A CN110970224A CN201811155853.7A CN201811155853A CN110970224A CN 110970224 A CN110970224 A CN 110970224A CN 201811155853 A CN201811155853 A CN 201811155853A CN 110970224 A CN110970224 A CN 110970224A
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- expanded graphite
- nickel
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 236
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 169
- 239000010439 graphite Substances 0.000 title claims abstract description 169
- 239000002131 composite material Substances 0.000 title claims abstract description 89
- BFDHFSHZJLFAMC-UHFFFAOYSA-L nickel(ii) hydroxide Chemical compound [OH-].[OH-].[Ni+2] BFDHFSHZJLFAMC-UHFFFAOYSA-L 0.000 title claims abstract description 82
- 239000002245 particle Substances 0.000 claims abstract description 19
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 140
- 229910052759 nickel Inorganic materials 0.000 claims description 62
- 238000001035 drying Methods 0.000 claims description 54
- 238000004070 electrodeposition Methods 0.000 claims description 52
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- 238000001132 ultrasonic dispersion Methods 0.000 claims description 34
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 28
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- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 20
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 18
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 16
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- 238000000151 deposition Methods 0.000 claims description 16
- 230000008021 deposition Effects 0.000 claims description 16
- -1 hydroxide ions Chemical class 0.000 claims description 16
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- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 12
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- 239000004966 Carbon aerogel Substances 0.000 claims description 7
- 229920002134 Carboxymethyl cellulose Polymers 0.000 claims description 6
- 229910021586 Nickel(II) chloride Inorganic materials 0.000 claims description 6
- 239000002033 PVDF binder Substances 0.000 claims description 6
- 239000002174 Styrene-butadiene Substances 0.000 claims description 6
- MQRWBMAEBQOWAF-UHFFFAOYSA-N acetic acid;nickel Chemical compound [Ni].CC(O)=O.CC(O)=O MQRWBMAEBQOWAF-UHFFFAOYSA-N 0.000 claims description 6
- 239000006230 acetylene black Substances 0.000 claims description 6
- 229910003481 amorphous carbon Inorganic materials 0.000 claims description 6
- 239000006229 carbon black Substances 0.000 claims description 6
- 239000002041 carbon nanotube Substances 0.000 claims description 6
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 6
- 229920006184 cellulose methylcellulose Polymers 0.000 claims description 6
- 239000002608 ionic liquid Substances 0.000 claims description 6
- 239000003273 ketjen black Substances 0.000 claims description 6
- 229940078494 nickel acetate Drugs 0.000 claims description 6
- QMMRZOWCJAIUJA-UHFFFAOYSA-L nickel dichloride Chemical compound Cl[Ni]Cl QMMRZOWCJAIUJA-UHFFFAOYSA-L 0.000 claims description 6
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 claims description 6
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 claims description 6
- KBJMLQFLOWQJNF-UHFFFAOYSA-N nickel(ii) nitrate Chemical compound [Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O KBJMLQFLOWQJNF-UHFFFAOYSA-N 0.000 claims description 6
- UIIMBOGNXHQVGW-UHFFFAOYSA-M sodium bicarbonate Substances [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 claims description 6
- 229910000030 sodium bicarbonate Inorganic materials 0.000 claims description 6
- 238000013329 compounding Methods 0.000 claims description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 4
- GOOHAUXETOMSMM-UHFFFAOYSA-N Propylene oxide Chemical compound CC1CO1 GOOHAUXETOMSMM-UHFFFAOYSA-N 0.000 claims description 4
- 229910021607 Silver chloride Inorganic materials 0.000 claims description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 239000010949 copper Substances 0.000 claims description 4
- WZWSOGGTVQXXSN-UHFFFAOYSA-N cyclohexanone;toluene Chemical compound CC1=CC=CC=C1.O=C1CCCCC1 WZWSOGGTVQXXSN-UHFFFAOYSA-N 0.000 claims description 4
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 claims description 4
- 229910052753 mercury Inorganic materials 0.000 claims description 4
- 229910000474 mercury oxide Inorganic materials 0.000 claims description 4
- UKWHYYKOEPRTIC-UHFFFAOYSA-N mercury(ii) oxide Chemical compound [Hg]=O UKWHYYKOEPRTIC-UHFFFAOYSA-N 0.000 claims description 4
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 4
- 229910052709 silver Inorganic materials 0.000 claims description 4
- 239000004332 silver Substances 0.000 claims description 4
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 claims description 4
- 229910001220 stainless steel Inorganic materials 0.000 claims description 4
- 239000010935 stainless steel Substances 0.000 claims description 4
- 229910052719 titanium Inorganic materials 0.000 claims description 4
- 239000010936 titanium Substances 0.000 claims description 4
- 239000011888 foil Substances 0.000 claims description 3
- 238000000034 method Methods 0.000 abstract description 25
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- 229910052786 argon Inorganic materials 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 229920001940 conductive polymer Polymers 0.000 description 4
- 238000005520 cutting process Methods 0.000 description 4
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- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 description 2
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- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
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- 241000282414 Homo sapiens Species 0.000 description 1
- 241000446313 Lamella Species 0.000 description 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
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- 125000004429 atom Chemical group 0.000 description 1
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- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 229910000000 metal hydroxide Inorganic materials 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
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Images
Classifications
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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
- H01G11/24—Electrodes characterised by structural features of the materials making up or comprised in the electrodes, e.g. form, surface area or porosity; characterised by the structural features of powders or particles used therefor
-
- 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
-
- 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
-
- 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
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention provides a nickel hydroxide/graphite composite material, which comprises super-expanded graphite and nickel hydroxide particles compounded on a graphite sheet layer. The nickel hydroxide/graphite composite material provided by the invention has a three-dimensional laminated sandwich structure, the conductivity of nickel hydroxide is improved, meanwhile, EG can provide a very high load surface area, and the change of the volume of nickel hydroxide caused in the charging and discharging process can be slowed down; on the other hand, the nickel hydroxide particles fixed on the EG sheet layer can prevent the EG sheet layer from being folded back to a certain extent so as to maintain good electrochemical performance.
Description
Technical Field
The invention belongs to the technical field of graphene, relates to a nickel hydroxide/graphite composite material, and particularly relates to a nickel hydroxide/expanded graphite composite material for a super capacitor.
Background
Novel energy storage devices such as super capacitors and lithium ion batteries meet the requirements of human beings on novel energy. In order to develop efficient energy storage devices, electrode materials play a significant role. Most of the electrode materials of the super capacitor commercialized at present are carbon materials with high specific surface area, such as activated carbon and carbon aerogel, but the energy density of the super capacitor assembled by the carbon materials is 10-100 times smaller than that of the battery. In order to increase the energy density of the super capacitor, research on pseudo-capacitance materials with high energy density, such as metal oxides and hydroxides (both of which have high theoretical specific capacitance), but the pseudo-capacitance materials have the disadvantages of poor conductivity, easy agglomeration of particles and the like. Therefore, in order to take advantage of the advantages of the carbon material such as high specific surface area and high electrical conductivity, and to provide a high loading area for the metal oxide (hydroxide), the carbon material has an effect of preventing particle agglomeration, and when the carbon material is compounded with a conductive polymer, the carbon material has a stable polymer structure, and overcomes the disadvantage of poor cycle stability caused by swelling during charge and discharge, and in recent years, metal oxide (hydroxide)/carbon, conductive polymer/carbon composite materials have been the focus of research.
Graphene is a two-dimensional carbon material consisting of carbon atoms hybridized by sp2 and having a thickness of one atom. Initially, graphene was considered an ideal quantum electrodynamics model in condensed state studies, which prompted graphene to be an attractive theoretical model. Since the graphene is prepared by Geim and the like in 2004 for the first time by adopting a micro-mechanical stripping method, the graphene attracts people's extensive attention because of excellent performances such as high conductivity, high specific surface area, high strength and high electron mobility, and further promotes the rapid development of the graphene preparation technology. Due to the excellent physicochemical properties, the material is widely applied to energy storage materials, environmental engineering and sensitive sensing, is called as 'black gold' or 'king of new materials', has a wide potential application prospect, and has become a focus and a research hotspot all over the world at present.
However, if graphene is used as an electrode material, the energy density is low, and thus, in the existing research, a metal oxide, graphene, a conductive polymer and graphene are compounded to prepare a pseudo-capacitor material. However, in practical applications, graphene still has many problems and restriction factors, and the preparation of graphene is a major obstacle that restricts the practical application and development of graphene. Although researchers have developed numerous methods for preparing graphene to date. Such as micro-electromechanical lift-off, epitaxial growth, intercalation lift-off, microwave assisted lift-off, arc discharge, chemical vapor deposition, and liquid phase reduced oxidation of graphite, among others. However, the practical problems of high price and the like caused by complex preparation method, rigorous requirements and low yield are still difficult to overcome, and the requirements of industrial mass production in reality cannot be met.
Therefore, how to find a more suitable composite material to solve the above-mentioned defects, which can be used as a pseudocapacitance material, has become one of the focuses of great attention of many research and development enterprises in the industry.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a nickel hydroxide/graphite composite material, and in particular, a nickel hydroxide/expanded graphite composite material for a supercapacitor, in which nickel hydroxide and super-expanded graphite are compounded to obtain a composite material having a three-dimensional lamellar structure, so that the electrical conductivity of nickel hydroxide is improved, and the back-folding of EG lamellae is prevented, thereby maintaining good electrochemical properties. Meanwhile, the production process is simple, the cost is low, and the material can be used as a pseudocapacitance material in the field of super capacitors.
The invention provides a nickel hydroxide/graphite composite material, which comprises super-expanded graphite and nickel hydroxide particles compounded on a graphite sheet layer.
Preferably, the nickel hydroxide particles are embedded between sheets of the super-expanded graphite;
the particle size of the nickel hydroxide particles is 10-100 nm;
the interlayer spacing of the super-expanded graphite is 0.01-10 mu m;
the sheet diameter of the super-expanded graphite is 1-100 nm;
the mass ratio of the super-expanded graphite to the nickel hydroxide is 1: (1-3).
Preferably, the super-expanded graphite is obtained by ultrasonically dispersing expanded graphite;
the super-expanded graphite is between expanded graphite and graphene;
the super-expanded graphite is ultrasonic intercalation expanded graphite;
the temperature of ultrasonic dispersion is 20-50 ℃;
the ultrasonic dispersion time is 2-4 h;
the composite material is obtained by carrying out ultrasonic dispersion on expanded graphite and then carrying out electrodeposition on the expanded graphite and a nickel source.
Preferably, a conductive agent and/or a binder can be added in the ultrasonic dispersion process;
the conductive agent comprises one or more of carbon nano tube, acetylene black, carbon black, ketjen black, graphite, graphene, amorphous carbon, carbon aerogel and nano porous carbon;
the mass ratio of the super-expanded graphite to the conductive agent is 100: (3-7);
the binder comprises one or more of PVDF, PTFE, SBR and CMC;
the mass ratio of the super-expanded graphite to the binder is 100: (1-3).
Preferably, the nickel hydroxide/graphite composite material is prepared by the following steps:
1) ultrasonically dispersing expanded graphite and a solvent to obtain slurry;
2) drying the slurry obtained in the step to obtain a super-expanded graphite block;
3) and taking the block obtained in the step as a working electrode, and carrying out electrochemical deposition in an electrolyte containing a nickel source to obtain the nickel hydroxide/graphite composite material.
Preferably, the concentration of the expanded graphite in the slurry is 0.1-5 g/L;
the drying comprises low-temperature vacuum drying;
the drying temperature is 30-60 ℃;
the drying time is 8-15 hours;
the electrochemically deposited counter electrode comprises one or more of nickel, platinum and carbon;
the reference electrode for electrochemical deposition comprises a silver/silver chloride reference electrode or a mercury/mercury oxide reference electrode.
Preferably, the deposition potential of the electrochemical deposition is 1-3V;
the time of the electrochemical deposition is 1-9 min;
the nickel source comprises one or more of nickel nitrate, nickel acetate, nickel sulfate and nickel chloride;
the concentration of the nickel source in the electrolyte is 0.1-1 mol/L;
the solvent of the electrolyte includes a solvent that can provide hydroxide ions.
Preferably, the solvent of the electrolyte comprises an organic solvent which is mutually soluble with water, water and NaHCO3One or more of a solution, a KOH solution, a NaOH solution and an ionic liquid capable of providing hydroxide ions;
a post-treatment step is also included after the electrochemical deposition;
the post-treatment comprises cleaning and drying;
the drying in the post-treatment comprises low-temperature vacuum drying;
the drying temperature is 30-60 ℃;
the drying time is 8-15 hours.
Preferably, the nickel hydroxide/graphite composite material can be prepared by the following steps:
1') carrying out ultrasonic dispersion on the expanded graphite, the binder and/or the conductive agent and the organic solvent to obtain slurry;
2') compounding the slurry obtained in the step on a current collector, and drying to obtain an intermediate;
3') taking the intermediate obtained in the step as a working electrode, and carrying out electrochemical deposition in an electrolyte containing a nickel source to obtain the nickel hydroxide/graphite composite material.
Preferably, the organic solvent comprises one or more of ethanol, methanol, isopropanol, benzene, toluene, pentane, styrene, diethyl ether, propylene oxide, acetone and toluene cyclohexanone;
the shape of the current collector comprises a foam shape, a foil shape or a net shape;
the current collector is made of one or more of nickel, stainless steel, titanium, aluminum, platinum and copper.
The invention provides a nickel hydroxide/graphite composite material, which comprises super-expanded graphite and nickel hydroxide particles compounded on a graphite sheet layer. Compared with the prior art, the preparation method aims at solving the practical problems that in the existing research of the pseudocapacitance material with high energy density, the metal oxide, the graphene, the conductive polymer and the graphene are compounded to prepare the pseudocapacitance material, the preparation method is complex, the requirement is harsh, the yield is low, the price is high and the like, and the requirement of the actual industrial mass production cannot be met.
The invention creatively takes specific super-expanded graphite as a carbon source, and inserts nickel hydroxide into graphite interlayer by an electrochemical intercalation method to obtain Ni (OH)2the/EG compound greatly improves the capacitance performance of the electrode material. The invention selects Ni (OH) from a plurality of metal oxides2As an electrode material of a super capacitor, the material has the advantages of low price, environmental friendliness, good chemical and thermal stability, high theoretical specific capacitance and the like. The nickel hydroxide/graphite composite material provided by the invention has a three-dimensional laminated sandwich structure, the conductivity of nickel hydroxide is improved, meanwhile, EG can provide a very high load surface area for the nickel hydroxide, and the change of the volume of the nickel hydroxide caused in the charging and discharging processes can be slowed down; on the other hand, the nickel hydroxide particles fixed on the EG sheet layer can prevent the EG sheet layer from being folded back to a certain extent so as to maintain good electrochemical performance. The composite material provided by the invention is Ni (OH)2And the super-expanded graphite and the nickel hydroxide have synergistic effect, have important significance for improving the electrochemical performance of the super capacitor, and effectively solve the problems that the preparation method of the graphene is complex, the agglomeration is serious, and the energy density is low when the graphene is simply used as an electrode material, and the nickel hydroxide has poor conductivity and the existing composite material preparation method is different and difficult to realize industrialization.
Experimental results show that the nickel hydroxide/graphite composite material prepared by the method has the advantages of high specific capacitance, good rate performance, long cycle life and the like, the specific capacitance of the electrode material is tested by using a cyclic voltammetry method, when the scanning rate is 2mV/s, the specific capacitance can reach 1634F/g, and after 1000 cycles, the capacity retention rate is 83%. And the compound has the advantages of simple preparation method, low price, easy amplification and good application prospect in the super capacitor.
Drawings
FIG. 1 is a CV curve of a composite electrode prepared in example 1 of the present invention;
FIG. 2 is a CV curve of a composite electrode prepared in example 2 of the present invention;
FIG. 3 is a CV curve of a composite electrode prepared in example 3 of the present invention;
FIG. 4 is a cycle life curve of a composite electrode prepared in example 3 of the present invention;
FIG. 5 is an SEM scanning electron micrograph of the super-expanded graphite prepared in example 3 of the present invention;
FIG. 6 is a SEM scanning electron micrograph of a composite electrode material prepared in example 3 of the invention.
Detailed Description
For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.
All of the starting materials of the present invention, without particular limitation as to their source, may be purchased commercially or prepared according to conventional methods well known to those skilled in the art.
All the raw materials of the invention are not particularly limited in purity, and the invention preferably adopts the purity requirements of analytical purity or the purity requirements of the conventional graphene preparation field.
All the raw materials, the marks and the acronyms thereof belong to the conventional marks and acronyms in the field, each mark and acronym is clear and definite in the field of related application, and the raw materials can be purchased from the market or prepared by a conventional method by the technical staff in the field according to the marks, the acronyms and the corresponding application.
The invention provides a nickel hydroxide/graphite composite material, which comprises super-expanded graphite and nickel hydroxide particles compounded on a graphite sheet layer.
The definition of the super-expanded graphite is not particularly limited, and can be conventionally defined by those skilled in the art, and can be selected and adjusted by those skilled in the art according to the actual production situation, the product requirement and the quality requirement, and the super-expanded graphite of the present invention means that the super-expanded graphite is between the expanded graphite and the graphene, especially the interlayer spacing is between the expanded graphite and the graphene, that is, the interlayer spacing is higher than that of the expanded graphite, but the single-sheet or few-sheet layer state of the graphene is not achieved. Compared with the expanded graphite, the super-expanded graphite has thinner lamella, larger interlayer spacing, obvious intercalation effect and simple preparation method.
The source of the super-expanded graphite is not particularly limited, and a person skilled in the art can select and adjust the super-expanded graphite according to the actual production condition, the product requirement and the quality requirement, wherein the super-expanded graphite is preferably ultrasonic intercalation expanded graphite, and more preferably obtained by performing ultrasonic dispersion on the expanded graphite.
The ultrasonic dispersion conditions are not particularly limited, conventional ultrasonic conditions well known to those skilled in the art can be adopted, and the selection and adjustment can be performed by the skilled in the art according to the actual production condition, the product requirement and the quality requirement, and the ultrasonic dispersion temperature is preferably 20-50 ℃, more preferably 25-45 ℃, and more preferably 30-40 ℃ to obtain a better super-expanded graphite structure. The time for ultrasonic dispersion is preferably 2-4 h, and more preferably 2.5-3.5 h.
The mode of the compounding is not particularly limited by the present invention, and can be selected and adjusted by those skilled in the art according to the practical application, product requirements and quality requirements, and the compounding of the present invention preferably includes one or more of deposition, doping, growth, embedding, loading, adhesion, coating and covering, more preferably deposition, doping, loading, growth or embedding, and most preferably deposition. The specific form of the complex can also be a physical complex or a chemical complex. Specifically, the composite material is preferably obtained by ultrasonically dispersing expanded graphite and then electrodepositing the expanded graphite and a nickel source.
The nickel hydroxide/graphite composite material, namely the nickel hydroxide/super-expanded graphite composite material, preferably has the nickel hydroxide particles embedded between the sheets of the super-expanded graphite and also deposited on the surfaces of the sheets of the super-expanded graphite. The specific parameters of the nickel hydroxide/graphite composite material are not particularly limited, and the conventional parameters of the composite material known to those skilled in the art can be used, and those skilled in the art can select and adjust the specific parameters according to the actual application condition, the product requirements and the quality requirements, and the particle size of the nickel hydroxide particles is preferably 10-100 nm, more preferably 30-80 nm, and more preferably 50-60 nm. The interlayer spacing of the super-expanded graphite is preferably 0.01-10 μm, more preferably 0.05-8 μm, more preferably 0.1-6 μm, more preferably 0.5-4 μm, and more preferably 1-3 μm. The preferred flake diameter of the super-expanded graphite is 1-100 nm, more preferred is 10-80 nm, more preferred is 30-60 nm, and more preferred is 40-50 nm. The mass ratio of the super-expanded graphite to the nickel hydroxide is preferably 1: (1-3), more preferably 1: (1.2 to 2.8), more preferably 1: (1.5-2.5), more preferably 1: (1.8-2.2).
In order to further improve the electrochemical performance of the composite material and better apply the composite material to a super capacitor, a conductive agent and/or a binder are preferably added in the ultrasonic dispersion process, and more preferably the conductive agent and the binder or the conductive agent is added.
The specific selection and addition amount of the conductive agent in the present invention are not particularly limited, and may be conventional conductive agents and addition amounts well known to those skilled in the art, and those skilled in the art can select and adjust the conductive agent according to actual application, product requirements and quality requirements, and the conductive agent in the present invention preferably includes one or more of carbon nanotube, acetylene black, carbon black, ketjen black, graphite, graphene, amorphous carbon, carbon aerogel and nanoporous carbon, and more preferably, carbon nanotube, acetylene black, carbon black, ketjen black, graphite, graphene, amorphous carbon, carbon aerogel or nanoporous carbon. The mass ratio of the super-expanded graphite to the conductive agent is preferably 100: (3-7), more preferably 100: (3.5 to 6.5), more preferably 100: (4-6), more preferably 100: (4.5-5.5).
The specific selection and addition amount of the binder in the present invention are not particularly limited, and may be conventional binders and addition amounts well known to those skilled in the art, and those skilled in the art can select and adjust the binder according to the actual application, product requirements and quality requirements, and the binder in the present invention preferably includes one or more of PVDF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), SBR (styrene butadiene rubber) and CMC (sodium carboxymethylcellulose), and more preferably PVDF, PTFE, SBR or CMC. The mass ratio of the super-expanded graphite and the binder is preferably 100: (1-3), more preferably 100: (1.2 to 2.8), more preferably 100: (1.5 to 2.5), more preferably 100: (1.7-2.2).
The invention also provides a preparation method of the nickel hydroxide/graphite composite material, which comprises the following steps:
1) ultrasonically dispersing expanded graphite and a solvent to obtain slurry;
2) drying the slurry obtained in the step to obtain a super-expanded graphite block;
3) and taking the block obtained in the step as a working electrode, and carrying out electrochemical deposition in an electrolyte containing a nickel source to obtain the nickel hydroxide/graphite composite material.
The selection and composition of the raw materials and the corresponding preferred principles in the preparation method of the nickel hydroxide/graphite composite material can correspond to the selection and composition of the raw materials and the corresponding preferred principles in the nickel hydroxide/graphite composite material, and are not described in detail herein.
The invention firstly obtains slurry after the expanded graphite and the solvent are dispersed by ultrasound.
The parameters and sources of the expanded graphite are not particularly limited in the present invention, and may be conventional parameters and sources known to those skilled in the art, and those skilled in the art can select and adjust the parameters and sources according to the actual application, product requirements and quality requirements. The solvent used in the present invention is not particularly limited, and may be any conventional solvent known to those skilled in the art, and those skilled in the art can select and adjust the solvent according to the actual application, product requirements and quality requirements, and the solvent used in the present invention may be water and/or organic solvents, and more preferably water and/or volatile organic solvents. The amount of the solvent is not particularly limited, and may be selected and adjusted by those skilled in the art according to practical application, product requirements and quality requirements, and in order to facilitate the dispersion of the expanded graphite, the concentration of the expanded graphite in the slurry is preferably 0.1 to 5g/L, more preferably 0.5 to 4.5g/L, more preferably 1 to 4g/L, and more preferably 2 to 3 g/L.
The ultrasonic dispersion conditions are not particularly limited, conventional ultrasonic conditions well known to those skilled in the art can be adopted, and the selection and adjustment can be performed by the skilled in the art according to the actual production condition, the product requirement and the quality requirement, and the ultrasonic dispersion temperature is preferably 20-50 ℃, more preferably 25-45 ℃, and more preferably 30-40 ℃ to obtain a better super-expanded graphite structure. The time for ultrasonic dispersion is preferably 2-4 h, and more preferably 2.5-3.5 h.
The invention then dries the slurry obtained in the above steps to obtain the super-expansion graphite block.
The drying conditions are not particularly limited, and conventional drying known to those skilled in the art can be adopted, and those skilled in the art can select and adjust the drying conditions according to actual production conditions, product requirements and quality requirements, in order to ensure the structure of the obtained super-expanded graphite, the drying temperature is not too high, freeze drying is not adopted, the drying mode is preferably vacuum drying, more preferably low-temperature vacuum drying, and the drying temperature is more preferably 30-60 ℃, more preferably 35-55 ℃, and more preferably 40-50 ℃. The drying time is preferably 8-15 hours, more preferably 9-14 hours, more preferably 10-13 hours, and more preferably 11-12 hours.
The super-expanded graphite block, namely the super-expanded graphite with a 3D three-dimensional shape, is obtained by the steps. The invention can obtain the super-expansion graphite block or powder, which is used as a working electrode for facilitating the subsequent electrochemical deposition, and the super-expansion graphite block is preferred.
The method finally uses the block obtained in the step as a working electrode, and obtains the nickel hydroxide/graphite composite material after electrochemical deposition in electrolyte containing a nickel source.
The counter electrode for electrochemical deposition according to the present invention is not particularly limited, and may be a conventional counter electrode well known to those skilled in the art, and may be selected and adjusted by those skilled in the art according to actual production conditions, product requirements and quality requirements, and preferably includes one or more of nickel, platinum and carbon, more preferably nickel, platinum or carbon, most preferably nickel, and particularly may be nickel foam. The reference electrode for electrochemical deposition according to the present invention is not particularly limited, and may be a conventional reference electrode well known to those skilled in the art, which may be selected and adjusted according to actual production conditions, product requirements and quality requirements, and preferably comprises a silver/silver chloride reference electrode or a mercury/mercury oxide reference electrode.
The electrolyte containing the nickel source is not particularly limited in the present invention, and a soluble nickel source may be added to a conventional electrolyte well known to those skilled in the art, and those skilled in the art may select and adjust the electrolyte according to actual production conditions, product requirements and quality requirements, and the nickel source in the present invention preferably includes one or more of nickel nitrate, nickel acetate, nickel sulfate and nickel chloride, and more preferably, nickel nitrate, nickel acetate, nickel sulfate or nickel chloride. The concentration of the nickel source in the electrolyte is preferably 0.1-1 mol/L, more preferably 0.3-0.8 mol/L, and more preferably 0.5-0.6 mol/L.
In order to ensure that the nickel hydroxide can be electrodeposited between the layers of the super-expanded graphite, the solvent of the electrolyte preferably comprises a solvent capable of providing hydroxide ions, and specifically comprises an organic solvent which is mutually soluble with water, water and NaHCO3One or more of a solution, a KOH solution, a NaOH solution and an ionic liquid capable of providing hydroxide ions, more preferably a water-miscible organic solvent and water, NaHCO3The solvent may be a solution, a KOH solution, a NaOH solution, or an ionic liquid capable of providing hydroxide ions, more preferably an organic solvent miscible with water and water, and particularly DMF and water.
The conditions of the electrochemical deposition are not particularly limited, and conventional electrochemical deposition conditions known by a person skilled in the art can be used, and the person skilled in the art can select and adjust the conditions according to actual production conditions, product requirements and quality requirements, and in order to obtain a composite material with a better intercalation structure, the deposition potential of the electrochemical deposition is preferably 1-3V, more preferably 1.2-2.8V, more preferably 1.5-2.5V, and more preferably 1.8-2.2V. The time of the electrochemical deposition is preferably 1-9 min, more preferably 2-8 min, and more preferably 4-6 min.
In order to further complete and optimize the production process and ensure the performance of the final product, the method preferably further comprises a post-treatment step after the electrochemical deposition. The post-treatment of the invention comprises washing and drying. The cleaning according to the present invention is preferably solvent cleaning followed by water cleaning. In order to ensure the structure of the obtained composite material, the drying temperature is not too high, freeze drying is not adopted, the drying mode is preferably vacuum drying, more preferably low-temperature vacuum drying, and the drying temperature is more preferably 30-60 ℃, more preferably 35-55 ℃, and more preferably 40-50 ℃. The drying time is preferably 8-15 hours, more preferably 9-14 hours, more preferably 10-13 hours, and more preferably 11-12 hours.
The invention further provides a preparation method of the nickel hydroxide/graphite composite material, which aims to further improve the electrochemical performance of a final product and optimize the preparation steps, and the preparation method is specifically prepared by the following steps:
1') carrying out ultrasonic dispersion on the expanded graphite, the binder and/or the conductive agent and the organic solvent to obtain slurry;
2') compounding the slurry obtained in the step on a current collector, and drying to obtain an intermediate;
3') taking the intermediate obtained in the step as a working electrode, and carrying out electrochemical deposition in an electrolyte containing a nickel source to obtain the nickel hydroxide/graphite composite material.
The selection and composition of the raw materials in the nickel hydroxide/graphite composite material and the corresponding optimization principle can correspond to the selection and composition of the raw materials in the nickel hydroxide/graphite composite material and the preparation method of the nickel hydroxide/graphite composite material and the corresponding optimization principle, and are not repeated herein.
The invention firstly carries out ultrasonic dispersion on the expanded graphite, the binder and/or the conductive agent and the organic solvent to obtain slurry.
The parameters and sources of the expanded graphite are not particularly limited in the present invention, and may be conventional parameters and sources known to those skilled in the art, and those skilled in the art can select and adjust the parameters and sources according to the actual application, product requirements and quality requirements. The specific choice of the organic solvent is not particularly limited in the present invention, and may be a conventional organic solvent well known to those skilled in the art, and those skilled in the art can select and adjust the organic solvent according to the actual application, product requirements and quality requirements, and the organic solvent in the present invention is preferably one or more of ethanol, methanol, isopropanol, benzene, toluene, pentane, styrene, diethyl ether, propylene oxide, acetone and toluene cyclohexanone, more preferably ethanol, methanol, isopropanol, benzene, toluene, pentane, styrene, diethyl ether, propylene oxide, acetone or toluene cyclohexanone, and more preferably a non-toxic volatile organic solvent.
The amount of the organic solvent is not particularly limited, and may be selected and adjusted by those skilled in the art according to practical application, product requirements and quality requirements, and in order to facilitate the dispersion of the expanded graphite, the concentration of the expanded graphite in the slurry is preferably 0.1 to 5g/L, more preferably 0.5 to 4.5g/L, more preferably 1 to 4g/L, and more preferably 2 to 3 g/L.
In order to further improve the electrochemical performance of the composite material and better apply the composite material to a super capacitor, the raw material preferably further comprises a conductive agent and/or a binder, and more preferably the conductive agent and the binder or the conductive agent.
The specific selection and addition amount of the conductive agent in the present invention are not particularly limited, and may be conventional conductive agents and addition amounts well known to those skilled in the art, and those skilled in the art can select and adjust the conductive agent according to actual application, product requirements and quality requirements, and the conductive agent in the present invention preferably includes one or more of carbon nanotube, acetylene black, carbon black, ketjen black, graphite, graphene, amorphous carbon, carbon aerogel and nanoporous carbon, and more preferably, carbon nanotube, acetylene black, carbon black, ketjen black, graphite, graphene, amorphous carbon, carbon aerogel or nanoporous carbon. The mass ratio of the super-expanded graphite to the conductive agent is preferably 100: (3-7), more preferably 100: (3.5 to 6.5), more preferably 100: (4-6), more preferably 100: (4.5-5.5).
The specific selection and addition amount of the binder in the present invention are not particularly limited, and may be conventional binders and addition amounts well known to those skilled in the art, and those skilled in the art can select and adjust the binder according to the actual application, product requirements and quality requirements, and the binder in the present invention preferably includes one or more of PVDF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), SBR (styrene butadiene rubber) and CMC (sodium carboxymethylcellulose), and more preferably PVDF, PTFE, SBR or CMC. The mass ratio of the super-expanded graphite and the binder is preferably 100: (1-3), more preferably 100: (1.2 to 2.8), more preferably 100: (1.5 to 2.5), more preferably 100: (1.7-2.2).
The ultrasonic dispersion conditions are not particularly limited, conventional ultrasonic conditions well known to those skilled in the art can be adopted, and the selection and adjustment can be performed by the skilled in the art according to the actual production condition, the product requirement and the quality requirement, and the ultrasonic dispersion temperature is preferably 20-50 ℃, more preferably 25-45 ℃, and more preferably 30-40 ℃ to obtain a better super-expanded graphite structure. The time for ultrasonic dispersion is preferably 2-4 h, and more preferably 2.5-3.5 h.
According to the invention, the slurry obtained in the above step is compounded on a current collector, and after drying, an intermediate is obtained.
The drying conditions are not particularly limited, and conventional drying known to those skilled in the art can be adopted, and those skilled in the art can select and adjust the drying conditions according to actual production conditions, product requirements and quality requirements, in order to ensure the structure of the obtained super-expanded graphite, the drying temperature is not too high, freeze drying is not adopted, the drying mode is preferably vacuum drying, more preferably low-temperature vacuum drying, and the drying temperature is more preferably 30-60 ℃, more preferably 35-55 ℃, and more preferably 40-50 ℃. The drying time is preferably 8-15 hours, more preferably 9-14 hours, more preferably 10-13 hours, and more preferably 11-12 hours.
The specific selection and form of the current collector in the present invention are not particularly limited, and may be conventional current collectors and forms well known to those skilled in the art, and those skilled in the art may select and adjust the current collector according to the actual application, product requirements and quality requirements, and the shape of the current collector in the present invention preferably includes a foam, a foil or a net, and more preferably a foam. The material of the current collector of the present invention preferably includes one or more of nickel, stainless steel, titanium, aluminum, platinum and copper, more preferably nickel, stainless steel, titanium, aluminum, platinum or copper, and still more preferably nickel. The current collector of the present invention is also preferably a pretreated current collector. The pretreatment according to the present invention preferably comprises washing and drying steps.
The intermediate obtained in the steps is used as a working electrode, and electrochemical deposition is carried out in an electrolyte containing a nickel source, so that the nickel hydroxide/graphite composite material is obtained.
The intermediate obtained in the step is used as a working electrode, and electrochemical deposition is carried out in an electrolyte containing a nickel source, so that the nickel hydroxide/graphite composite material is obtained.
The counter electrode for electrochemical deposition according to the present invention is not particularly limited, and may be a conventional counter electrode well known to those skilled in the art, and may be selected and adjusted by those skilled in the art according to actual production conditions, product requirements and quality requirements, and preferably includes one or more of nickel, platinum and carbon, more preferably nickel, platinum or carbon, most preferably nickel, and particularly may be nickel foam. The reference electrode for electrochemical deposition according to the present invention is not particularly limited, and may be a conventional reference electrode well known to those skilled in the art, which may be selected and adjusted according to actual production conditions, product requirements and quality requirements, and preferably comprises a silver/silver chloride reference electrode or a mercury/mercury oxide reference electrode.
The electrolyte containing the nickel source is not particularly limited in the present invention, and a soluble nickel source may be added to a conventional electrolyte well known to those skilled in the art, and those skilled in the art may select and adjust the electrolyte according to actual production conditions, product requirements and quality requirements, and the nickel source in the present invention preferably includes one or more of nickel nitrate, nickel acetate, nickel sulfate and nickel chloride, and more preferably, nickel nitrate, nickel acetate, nickel sulfate or nickel chloride. The concentration of the nickel source in the electrolyte is preferably 0.1-1 mol/L, more preferably 0.3-0.8 mol/L, and more preferably 0.5-0.6 mol/L.
In order to ensure that the nickel hydroxide can be electrodeposited between the layers of the super-expanded graphite, the solvent of the electrolyte preferably comprises a solvent capable of providing hydroxide ions, and specifically comprises an organic solvent which is mutually soluble with water, water and NaHCO3One or more of a solution, a KOH solution, a NaOH solution and an ionic liquid capable of providing hydroxide ions, more preferably a water-miscible organic solvent and water, NaHCO3The solvent may be a solution, a KOH solution, a NaOH solution, or an ionic liquid capable of providing hydroxide ions, more preferably an organic solvent miscible with water and water, and particularly DMF and water.
The conditions of the electrochemical deposition are not particularly limited, and conventional electrochemical deposition conditions known by a person skilled in the art can be used, and the person skilled in the art can select and adjust the conditions according to actual production conditions, product requirements and quality requirements, and in order to obtain a composite material with a better intercalation structure, the deposition potential of the electrochemical deposition is preferably 1-3V, more preferably 1.2-2.8V, more preferably 1.5-2.5V, and more preferably 1.8-2.2V. The time of the electrochemical deposition is preferably 1-9 min, more preferably 2-8 min, and more preferably 4-6 min.
In order to further complete and optimize the production process and ensure the performance of the final product, the method preferably further comprises a post-treatment step after the electrochemical deposition. The post-treatment of the invention comprises washing and drying. The cleaning according to the present invention is preferably solvent cleaning followed by water cleaning. In order to ensure the structure of the obtained composite material, the drying temperature is not too high, freeze drying is not adopted, the drying mode is preferably vacuum drying, more preferably low-temperature vacuum drying, and the drying temperature is more preferably 30-60 ℃, more preferably 35-55 ℃, and more preferably 40-50 ℃. The drying time is preferably 8-15 hours, more preferably 9-14 hours, more preferably 10-13 hours, and more preferably 11-12 hours.
In order to ensure the structure and electrochemical performance of the final product, complete and detailed preparation process, the preparation steps can be as follows:
(1) foam nickel pretreatment: cutting foamed Nickel (NF) into 1 × 1cm2And 2X 2cm2And (3) carrying out ultrasonic cleaning on the powder by using acetone, ethanol and deionized water in sequence, putting the powder into a vacuum drying oven, and carrying out vacuum drying for later use.
(2) Ultrasonic treatment of expanded graphite: dispersing expanded graphite, a binder and a conductive agent in a small bottle containing ethanol according to a mass ratio, and placing the small bottle containing ethanol into an ultrasonic dispersion machine for ultrasonic dispersion to obtain uniform slurry, wherein the ultrasonic temperature is controlled to be 20-50 ℃, and the ultrasonic time is 2-4 hours.
(3) Coating expanded graphite: the resulting slurry was uniformly coated on a treated and weighed 1X 1cm of m1 mass2On foamed nickel; finally, the mixture is placed into a vacuum drying oven and dried and thenThe sub-weights are recorded as m 2.
(4) Electro-deposition: using DMF and H2The solution mixed with O is used as an electrolyte solvent; 0.1 to 1mol/LNi (NO)3)2As an electrolyte; 1 x 1cm of expanded graphite material coated in step (3)2The foamed nickel of (2X 2 cm) is a Working Electrode (WE)2The nickel foam of (a) is a Counter Electrode (CE) and a Reference Electrode (RE). And after argon is introduced to remove oxygen in the electrolyte, performing electrodeposition under a constant potential, wherein the deposition potential is preferably 1-3V, and the deposition time is controlled within 1-9 min.
(5) And washing the obtained pole piece with water, drying, washing with ethanol and deionized water after electrodeposition to remove residual solvent and electrolyte ions on the surface, finally drying in a vacuum drying oven, and weighing, wherein the mass is recorded as m 3. Prepared electrode Ni (OH)2and/EG/NF.
The invention creatively takes specific super-expanded graphite as a carbon source, and embeds nickel hydroxide into graphite layers by an electrochemical intercalation method to obtain Ni (OH)2the/EG compound greatly improves the capacitance performance of the electrode material. The invention selects Ni (OH) from a plurality of metal oxides2As an electrode material of a super capacitor, the material has the advantages of low price, environmental friendliness, good chemical and thermal stability, high theoretical specific capacitance and the like. The nickel hydroxide/graphite composite material provided by the invention has a three-dimensional laminated sandwich structure, the conductivity of nickel hydroxide is improved, meanwhile, EG can provide a very high load surface area for the nickel hydroxide, and the change of the volume of the nickel hydroxide caused in the charging and discharging processes can be slowed down; on the other hand, the nickel hydroxide particles fixed on the EG sheet layer can prevent the EG sheet layer from being folded back to a certain extent so as to maintain good electrochemical performance. The composite material provided by the invention is Ni (OH)2The nickel hydroxide and the super-expanded graphite have synergistic effect, so that the method has important significance for improving the electrochemical performance of the super capacitor, effectively solves the problems that the graphene preparation method is complex, the agglomeration is serious, the graphene is only used as an electrode material and the energy density is low, the nickel hydroxide has poor conductivity, and the existing composite material preparation method is different and difficult to realizeThe defect of industrialization.
The invention also particularly adopts an electrochemical deposition method to prepare the electrode material of the super capacitor, and is expected to be widely applied due to low cost, simple preparation process, controllable thickness (quality) of the electrode active substance and controllable structure of the material. The method takes expanded graphite as a raw material, obtains graphene-like material as an experimental precursor through ultrasonic mechanical stripping, and then prepares the nickel hydroxide/graphite composite material through constant potential electrochemical deposition. The method not only saves the complex graphene preparation step, greatly reduces the preparation cost of the electrode material, but also improves the capacitance performance of the electrode material; and EG in the prepared compound has the property similar to graphene, and has higher and more practical application value.
The invention provides a nickel hydroxide/expanded graphite composite material for a supercapacitor, which is prepared by embedding nickel hydroxide into graphite interlayers by adopting an electrochemical intercalation method to obtain Ni (OH)2And a super-expanded graphite (graphene-like) material, which is a composite material with an inserted layered structure, has a novel structure and excellent performance, and can be added with a conductive agent to improve the electrochemical performance. The invention adopts electrochemical deposition, preferably uses specific constant potential deposition, realizes one-step electrodeposition to obtain Ni (OH)2. And the proper drying temperature is adopted, so that the stable structure of the final product is ensured, the method is simple, the cost is saved, and the industrialization is easy to realize.
Experimental results show that the nickel hydroxide/graphite composite material prepared by the method has the advantages of high specific capacitance, good rate performance, long cycle life and the like, the specific capacitance of the electrode material is tested by using a cyclic voltammetry method, when the scanning rate is 2mV/s, the specific capacitance can reach 1634F/g, and after 1000 cycles, the capacity retention rate is 83%. And the compound has the advantages of simple preparation method, low price, easy amplification and good application prospect in the super capacitor.
For further illustration of the present invention, a nickel hydroxide/graphite composite material provided by the present invention will be described in detail with reference to the following examples, but it should be understood that these examples are carried out on the premise of the technical solution of the present invention, and the detailed embodiments and specific procedures are given only for further illustration of the features and advantages of the present invention, not for limitation of the claims of the present invention, and the scope of protection of the present invention is not limited to the following examples.
Example 1
Firstly, cutting foam Nickel (NF) into 1 × 1cm2And 2X 2cm2Placing the mixture into a 100mL beaker, ultrasonically cleaning the mixture by using acetone, ethanol and deionized water in sequence, placing the mixture into a vacuum drying oven, and drying the mixture for 6 hours at 70 ℃ in vacuum for later use;
then weighing 18mg of expanded graphite, PVDF1mg and CNTs1mg, putting the expanded graphite, the PVDF1mg and the CNTs1mg into a small bottle containing 10mL of ethanol, and putting the small bottle into an ultrasonic dispersion machine for ultrasonic dispersion for 3 hours, wherein the temperature of the ultrasonic dispersion machine is controlled to be 30 ℃;
the resulting slurry was uniformly coated on a treated and weighed 1X 1cm of m12Finally, putting the nickel foam into a vacuum drying oven, and drying for 6 hours at 60 ℃, wherein the mass of the expanded graphite coated on the nickel foam is about 1 mg;
finally, nickel hydroxide is deposited on the foamed nickel substrate coated with the expanded graphite, and electrodeposition uses a mixed solution of DMF and PC as an electrolyte solvent, 0.5mol/L of Ni (NO)3)21X 1cm coated with expanded graphite material as electrolyte2The foamed nickel of (2X 2 cm) is a Working Electrode (WE)2The nickel foam of (a) is a Counter Electrode (CE) and a Reference Electrode (RE). And after argon is introduced to remove oxygen in the electrolyte, carrying out electrodeposition under a constant potential, wherein the deposition potential is 1V, and the deposition time is controlled to be 9 min.
After the electrodeposition, the film is washed by ethanol and deionized water to remove residual solvent and electrolyte ions on the surface, and finally the film is dried in a vacuum drying oven at 70 ℃ for 6 hours and weighed to obtain the mass of about 3 mg.
Electrochemical tests were performed on the composite electrode prepared in example 1 of the present invention.
Referring to fig. 1, fig. 1 is a CV curve of a composite electrode prepared in example 1 of the present invention.
Referring to table 1, table 1 is test data of CV curves of the composite electrode prepared in example 1 of the present invention.
TABLE 1
| Scanning rate | 2mV/s | 5mV/s | 10mV/s | 20mV/s |
| Specific capacitance (F/g) | 1162 | 1104 | 1085 | 983 |
As can be seen from FIG. 1 and Table 1, the specific capacitance can reach 1162F/g at a sweep rate of 2mV/s under cyclic voltammetry test.
Example 2
Firstly, cutting foam Nickel (NF) into 1 × 1cm2And 2X 2cm2Placing the mixture into a 100mL beaker, ultrasonically cleaning the mixture by using acetone, ethanol and deionized water in sequence, placing the mixture into a vacuum drying oven, and drying the mixture for 6 hours at 70 ℃ in vacuum for later use;
then weighing 18mg of expanded graphite, PVDF1mg and CNTs1mg, putting the expanded graphite, the PVDF1mg and the CNTs1mg into a small bottle containing 10mL of ethanol, and putting the small bottle into an ultrasonic dispersion machine for ultrasonic dispersion for 4 hours, wherein the temperature of the ultrasonic dispersion machine is controlled to be 30 ℃;
the resulting slurry was uniformly coated on a treated and weighed 1X 1cm of m12Finally, the nickel foam is placed into a vacuum drying oven to be dried for 6 hours at 60 ℃, and the mass of the expanded graphite coated on the nickel foam is about1mg；
Finally, nickel hydroxide is deposited on the foamed nickel substrate coated with the expanded graphite, and electrodeposition uses a mixed solution of DMF and PC as an electrolyte solvent, 0.5mol/L of Ni (NO)3)21X 1cm coated with expanded graphite material as electrolyte2The foamed nickel of (2X 2 cm) is a Working Electrode (WE)2The nickel foam of (a) is a Counter Electrode (CE) and a Reference Electrode (RE). And after argon is introduced to remove oxygen in the electrolyte, carrying out electrodeposition under a constant potential, wherein the deposition potential is 1V, and the deposition time is controlled to be 9 min.
After the electrodeposition, the film is washed by ethanol and deionized water to remove residual solvent and electrolyte ions on the surface, and finally the film is dried in a vacuum drying oven at 70 ℃ for 6 hours and weighed to obtain the mass of about 3 mg.
Electrochemical tests were performed on the composite electrode prepared in example 2 of the present invention.
Referring to fig. 2, fig. 2 is a CV curve of the composite electrode prepared in example 2 of the present invention.
Referring to table 2, table 2 is test data of CV curves of the composite electrode prepared in example 2 of the present invention.
TABLE 2
| Scanning rate | 2mV/s | 5mV/s | 10mV/s | 20mV/s |
| Specific capacitance (F/g) | 1346 | 1285 | 1208 | 1081 |
As shown in FIG. 2 and Table 2, the specific capacitance can reach 1346F/g at a sweep rate of 2mV/s under cyclic voltammetry test.
Example 3
Firstly, cutting foam Nickel (NF) into 1 × 1cm2And 2X 2cm2Placing the mixture into a 100mL beaker, ultrasonically cleaning the mixture by using acetone, ethanol and deionized water in sequence, placing the mixture into a vacuum drying oven, and drying the mixture for 6 hours at 70 ℃ in vacuum for later use;
then weighing 18mg of expanded graphite, PVDF1mg and CNTs1mg, putting the expanded graphite, the PVDF1mg and the CNTs1mg into a small bottle containing 10mL of ethanol, and putting the small bottle into an ultrasonic dispersion machine for ultrasonic dispersion for 4 hours, wherein the temperature of the ultrasonic dispersion machine is controlled to be 30 ℃;
the resulting slurry was uniformly coated on a treated and weighed 1X 1cm of m12Finally, putting the nickel foam into a vacuum drying oven, and drying for 6 hours at 60 ℃, wherein the mass of the expanded graphite coated on the nickel foam is about 1 mg;
finally, nickel hydroxide is deposited on the foamed nickel substrate coated with the expanded graphite, and electrodeposition uses a mixed solution of DMF and PC as an electrolyte solvent, 0.5mol/L of Ni (NO)3)21X 1cm coated with expanded graphite material as electrolyte2The foamed nickel of (2X 2 cm) is a Working Electrode (WE)2The nickel foam of (a) is a Counter Electrode (CE) and a Reference Electrode (RE). And after argon is introduced to remove oxygen in the electrolyte, carrying out electrodeposition under a constant potential, wherein the deposition potential is 3V, and the deposition time is controlled to be 1 min.
After the electrodeposition, the film is washed by ethanol and deionized water to remove residual solvent and electrolyte ions on the surface, and finally the film is dried in a vacuum drying oven at 70 ℃ for 6 hours and weighed to obtain the mass of about 3 mg.
Electrochemical tests were performed on the composite electrode prepared in example 3 of the present invention.
Referring to fig. 3, fig. 3 is a CV curve of a composite electrode prepared in example 3 of the present invention.
Referring to fig. 4, fig. 4 is a cycle life curve of a composite electrode prepared in example 3 of the present invention.
Referring to table 3, table 3 is test data of CV curves of the composite electrode prepared in example 3 of the present invention.
TABLE 3
| Scanning rate | 2mV/s | 5mV/s | 10mV/s | 20mV/s |
| Specific capacitance (F/g) | 1634 | 1586 | 1495 | 1280 |
As shown in FIG. 3 and Table 3, the specific capacitance reached 1634F/g at a sweep rate of 2mV/s under cyclic voltammetry, and the capacity retention was 83% after 1000 cycles.
The super-expanded graphite and the composite electrode material prepared in example 3 of the present invention were characterized.
Referring to fig. 5, fig. 5 is an SEM scanning electron micrograph of the super expanded graphite prepared in example 3 of the present invention.
As can be seen from FIG. 5, the super-expanded graphite prepared by the present invention has a significant view of the gaps between the sheets, and has a larger distance between the sheets than the expanded graphite.
Referring to fig. 6, fig. 6 is a SEM scanning electron micrograph of the composite electrode material prepared in example 3 of the present invention.
As can be seen from fig. 6, in the composite material provided by the present invention, the particulate nickel hydroxide is uniformly distributed on the surface of the graphene-like material, indicating that the two materials are well combined.
While the present invention has been described in detail with reference to the particular embodiments thereof, the principles and implementations of the present invention are described herein using specific examples, which are set forth to provide an understanding of the method and its core concepts, including the best mode, and to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention. The scope of the invention is defined by the claims and may include other embodiments that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
Claims (10)
1. A nickel hydroxide/graphite composite material is characterized by comprising super-expanded graphite and nickel hydroxide particles compounded on a graphite sheet layer.
2. The composite material according to claim 1, wherein the nickel hydroxide particles are intercalated between sheets of the super expanded graphite;
the particle size of the nickel hydroxide particles is 10-100 nm;
the interlayer spacing of the super-expanded graphite is 0.01-10 mu m;
the sheet diameter of the super-expanded graphite is 1-100 nm;
the mass ratio of the super-expanded graphite to the nickel hydroxide is 1: (1-3).
3. The composite material of claim 1, wherein the super-expanded graphite is obtained by ultrasonically dispersing expanded graphite;
the super-expanded graphite is between expanded graphite and graphene;
the super-expanded graphite is ultrasonic intercalation expanded graphite;
the temperature of ultrasonic dispersion is 20-50 ℃;
the ultrasonic dispersion time is 2-4 h;
the composite material is obtained by carrying out ultrasonic dispersion on expanded graphite and then carrying out electrodeposition on the expanded graphite and a nickel source.
4. The composite material according to claim 3, wherein a conductive agent and/or a binder can be further added during the ultrasonic dispersion;
the conductive agent comprises one or more of carbon nano tube, acetylene black, carbon black, ketjen black, graphite, graphene, amorphous carbon, carbon aerogel and nano porous carbon;
the mass ratio of the super-expanded graphite to the conductive agent is 100: (3-7);
the binder comprises one or more of PVDF, PTFE, SBR and CMC;
the mass ratio of the super-expanded graphite to the binder is 100: (1-3).
5. The composite material of claim 1, wherein the nickel hydroxide/graphite composite material is prepared by the steps of:
1) ultrasonically dispersing expanded graphite and a solvent to obtain slurry;
2) drying the slurry obtained in the step to obtain a super-expanded graphite block;
3) and taking the block obtained in the step as a working electrode, and carrying out electrochemical deposition in an electrolyte containing a nickel source to obtain the nickel hydroxide/graphite composite material.
6. The composite material according to claim 5, wherein the concentration of the expanded graphite in the slurry is 0.1 to 5 g/L;
the drying comprises low-temperature vacuum drying;
the drying temperature is 30-60 ℃;
the drying time is 8-15 hours;
the electrochemically deposited counter electrode comprises one or more of nickel, platinum and carbon;
the reference electrode for electrochemical deposition comprises a silver/silver chloride reference electrode or a mercury/mercury oxide reference electrode.
7. The composite material of claim 5, wherein the deposition potential of the electrochemical deposition is 1-3V;
the time of the electrochemical deposition is 1-9 min;
the nickel source comprises one or more of nickel nitrate, nickel acetate, nickel sulfate and nickel chloride;
the concentration of the nickel source in the electrolyte is 0.1-1 mol/L;
the solvent of the electrolyte includes a solvent that can provide hydroxide ions.
8. The composite material of claim 5, wherein the solvent of the electrolyte comprises a water-miscible organic solvent and water, NaHCO3One or more of a solution, a KOH solution, a NaOH solution and an ionic liquid capable of providing hydroxide ions;
a post-treatment step is also included after the electrochemical deposition;
the post-treatment comprises cleaning and drying;
the drying in the post-treatment comprises low-temperature vacuum drying;
the drying temperature is 30-60 ℃;
the drying time is 8-15 hours.
9. The composite material of claim 4, wherein the nickel hydroxide/graphite composite material is prepared by the steps of:
1') carrying out ultrasonic dispersion on the expanded graphite, the binder and/or the conductive agent and the organic solvent to obtain slurry;
2') compounding the slurry obtained in the step on a current collector, and drying to obtain an intermediate;
3') taking the intermediate obtained in the step as a working electrode, and carrying out electrochemical deposition in an electrolyte containing a nickel source to obtain the nickel hydroxide/graphite composite material.
10. The composite material of claim 9, wherein the organic solvent comprises one or more of ethanol, methanol, isopropanol, benzene, toluene, pentane, styrene, diethyl ether, propylene oxide, acetone, and toluene cyclohexanone;
the shape of the current collector comprises a foam shape, a foil shape or a net shape;
the current collector is made of one or more of nickel, stainless steel, titanium, aluminum, platinum and copper.
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| CN201811155853.7A CN110970224A (en) | 2018-09-30 | 2018-09-30 | Nickel hydroxide/graphite composite material |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102012220984A1 (en) * | 2012-11-29 | 2014-05-22 | Xerox Corporation | Preparing expanded graphite, useful in producing graphene product, comprises placing expandable graphite in chamber, applying vacuum to chamber, and applying electric current for induction heating of expandable graphite in vacuum |
| CN104616908A (en) * | 2015-01-29 | 2015-05-13 | 西南石油大学 | Composite material of nickel hydroxide/graphene or graphite and preparation method for composite material |
| CN109192523A (en) * | 2018-08-09 | 2019-01-11 | 杭州电子科技大学 | A kind of Ni (OH)2The preparation method of/multi-layer graphene composite material |
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2018
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102012220984A1 (en) * | 2012-11-29 | 2014-05-22 | Xerox Corporation | Preparing expanded graphite, useful in producing graphene product, comprises placing expandable graphite in chamber, applying vacuum to chamber, and applying electric current for induction heating of expandable graphite in vacuum |
| CN104616908A (en) * | 2015-01-29 | 2015-05-13 | 西南石油大学 | Composite material of nickel hydroxide/graphene or graphite and preparation method for composite material |
| CN109192523A (en) * | 2018-08-09 | 2019-01-11 | 杭州电子科技大学 | A kind of Ni (OH)2The preparation method of/multi-layer graphene composite material |
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