CN103258656B - Preparation method of a kind of electrode of super capacitor based on nickel foam and products thereof - Google Patents

Abstract

The invention discloses a kind of preparation method of the Asymmetric Supercapacitor electrode based on nickel foam, comprising: nickel foam is cleaned, be then dipped into the nickel foam obtaining in graphene oxide water solution and deposit graphene oxide; To deposit the nickel foam of graphene oxide for persursor material, adopt three-electrode method to make the both positive and negative polarity of Asymmetric Supercapacitor respectively, and this both positive and negative polarity is made up of respectively graphene/carbon nano-tube/nickel foam and Graphene/manganese dioxide/nickel foam composite material.The invention also discloses preparation method and the corresponding product thereof of some other electrode of super capacitor based on similar principles.By the present invention, composite material high specific capacitance feature separately can be given full play to, improve the energy density of ultracapacitor; In addition, the use of various groups of agent can be avoided, corresponding so that the mode of manipulation, low cost, low energy consumption performs mass industrialized production.

Description

A kind of preparation method and product thereof based on nickel foam supercapacitor electrode

technical field

The invention belongs to the technical field of supercapacitors, and more specifically relates to a method for preparing supercapacitor electrodes based on nickel foam and products thereof.

Background technique

Supercapacitor is a high-energy and green energy storage device with performance between batteries and traditional capacitors. Because of its advantages such as high power density, fast charge and discharge speed, long cycle life and wide operating temperature range, it is widely used in electric vehicles, It has been widely used in many fields such as communication and electronic consumption. According to different energy storage mechanisms, supercapacitors can be divided into electric double layer capacitors and faraday quasi capacitors, in which electric double layer capacitors use the interface electric double layer capacitance formed between electrodes and electrolytes to store energy, Faraday quasi capacitors are in On the two-dimensional or quasi-two-dimensional space in the surface or bulk phase, the underpotential deposition is performed by the electrode active material, so that it can store energy through Faraday charge transfer reaction. In addition, in order to obtain higher energy density and power density at the same time, a new type of supercapacitor that combines the advantages of the above two types of supercapacitors, that is, an asymmetric supercapacitor, has been designed. layer electrode, and the other pole uses a Faraday quasi-capacitive electrode.

One of the key factors determining the performance of the supercapacitor is the electrode material it uses. At present, the electrodes of electric double-layer capacitors usually use porous carbon materials and their composites with high specific surface area, and the electrode materials of Faraday quasi-capacitors usually use metal oxides or conductive polymers. For example, a porous carbon supercapacitor electrode material and its preparation method are disclosed in CN200910243306.9, wherein zinc chloride is used as a template and a catalyst, and fructose is used as a precursor, dissolved in deionized water and stirred in an oil bath, Then calcining under protective atmosphere thus obtains porous carbon supercapacitor material; CN200710074617.8 discloses a method for preparing C/V ₂ O ₅ supercapacitor film electrodes based on Faraday pseudocapacitance, wherein the principle is based on metal vanadium and hydrogen peroxide , first prepare vanadium sol by liquid phase reaction method, then add conductive carbon material and stir evenly, and finally form C/V ₂ O ₅ supercapacitor film electrode on the surface of stainless steel foil by pulling method.

For asymmetric supercapacitors, the electrode system mainly includes carbon material/metal oxide system, conductive polymer/carbon material system and lithium titanium oxide compound/activated carbon (AC) system, etc. Among them, for the carbon material/metal oxide system, the most typical example is that the positive electrode uses RuO ₂ , the negative electrode uses activated carbon, and the electrolyte uses H ₂ SO ₄ . The specific capacity of the prepared hybrid supercapacitor can reach 770F/g , the specific energy reaches 2617Wh/kg. However, due to the high cost of ruthenium, the application has been greatly limited. Therefore, it has become an important topic in recent years to synthesize composite materials of RuO ₂ and other metal oxides to reduce the amount of RuO ₂ , or to find other metal oxides to replace rare and precious metals. where the research hotspots are. For example, CN200910113946.8 discloses a hybrid supercapacitor and its manufacturing method, wherein the positive electrode is made of carbon material for electric double-layer capacitors, which is mixed with graphite powder and then added with polytetrafluoroethylene emulsion and then filled in nickel foam; the negative electrode is made of Hydrogen storage alloy sheets, nickel oxide or manganese dioxide with quasi-capacitive properties, or composite materials made of carbon materials and nickel oxide or manganese dioxide, can be assembled in this way to obtain a hybrid supercapacitor. In addition, CN201210142685.4 discloses a manganese dioxide asymmetric supercapacitor and its preparation method, wherein manganese dioxide or manganese dioxide/activated carbon composite material is used as the positive electrode active material, pitch-based activated carbon, activated carbon fiber, carbon nano One of tubes or graphene is used as the negative electrode active material, and then it is respectively mixed into the conductive electrode and the binder, and then coated on the nickel foam to make the positive and negative electrodes.

However, studies have shown that at present, in the process of preparing supercapacitor electrodes, it is often necessary to incorporate acetylene black or conductive graphite as a conductive agent, and at the same time incorporate polytetrafluoroethylene, polyvinylidene fluoride or similar materials as a binder, which not only makes The preparation process is complicated, the cost becomes higher, and it will also affect the performance of the electrode material itself; on the other hand, with the rise of electric vehicles and hybrid electric vehicles, under the premise of maintaining high power and long life of supercapacitors, the energy Density is becoming a research hotspot in supercapacitors. In order to obtain a supercapacitor with better comprehensive performance and meet the increasing application requirements of new technologies and new fields, it is becoming an urgent technical problem to be solved in related fields to find other composite materials with good performance to replace the above electrode materials.

Contents of the invention

Aiming at the above defects or improvement needs of the prior art, the present invention provides a method for preparing supercapacitor electrodes based on nickel foam and its products. The high specific capacitance feature further improves the energy density of supercapacitors; in addition, by using aqueous electrolyte assembly, the use of various components can be avoided, and electrodes and Supercapacitor products are environmentally friendly and suitable for mass industrial production.

According to a first aspect of the present invention, there is provided a method for preparing an asymmetric supercapacitor electrode based on nickel foam, characterized in that the method comprises the following steps:

(a) cleaning the nickel foam, and then immersing it in an aqueous solution of graphene oxide with a mass concentration of 1 mg/ml to 10 mg/ml, thereby obtaining nickel foam deposited with graphene oxide;

(b) Use the nickel foam deposited with graphene oxide as the precursor material to make the positive and negative electrodes of the asymmetric supercapacitor respectively. The specific process is as follows:

(b1) A three-electrode method was used to perform constant-voltage electrochemical reduction of the precursor material, in which nickel foam deposited with graphene oxide was used as the working electrode, a platinum electrode was used as the auxiliary electrode, and a saturated calomel electrode was used as the reference electrode. The molar concentration 0.1mol/L～1mol/L sulfate aqueous solution is used as the electrolyte to prepare the nickel foam deposited with graphene in this way; then soak the nickel foam electrode deposited with graphene to a mass concentration of 0.2mg/ml～ 2mg/ml of carbon nanotube aqueous solution and take out and dry, thereby making nickel foam with carbon nanotubes and graphene deposited at the same time, and use it as the negative electrode of an asymmetric supercapacitor;

(b2) Perform cyclic voltammetric electrochemical deposition on the precursor material using a three-electrode method, in which nickel foam deposited on graphene oxide is used as the working electrode, a platinum electrode is used as the auxiliary electrode, and a saturated calomel electrode is used as the reference electrode, molar An aqueous solution of manganese acetate with a concentration of 0.1mol/L-1mol/L is used as an electrolyte, and nickel foam with manganese dioxide and graphene deposited simultaneously is prepared in this way, and it is used as the positive electrode of an asymmetric supercapacitor.

According to a second aspect of the present invention, a kind of preparation method of the supercapacitor electrode based on nickel foam is provided, it is characterized in that, the method comprises the following steps:

(i) cleaning the nickel foam, and then immersing it in an aqueous solution of graphene oxide with a mass concentration of 1 mg/ml to 10 mg/ml, thereby obtaining nickel foam deposited with graphene oxide;

(ii) Constant-voltage electrochemical reduction was performed on GO-deposited nickel foam by a three-electrode method, in which the GO-deposited nickel foam was used as the working electrode, the platinum electrode was used as the auxiliary electrode, and the saturated calomel electrode was used as the reference electrode , molar concentration is 0.1mol/L～1mol/L sulfate aqueous solution is used as electrolyte, in this way the nickel foam deposited with graphene is prepared, and it is used as the electrode of supercapacitor.

According to a third aspect of the present invention, a kind of preparation method of the supercapacitor electrode based on nickel foam is provided, it is characterized in that, the method comprises the following steps:

(A) Cleaning the nickel foam, and then immersing it in an aqueous solution of graphene oxide with a mass concentration of 1 mg/ml to 10 mg/ml, thereby obtaining nickel foam deposited with graphene oxide;

(B) Constant-voltage electrochemical reduction of nickel foam deposited with graphene oxide by a three-electrode method, in which the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the auxiliary electrode, and the saturated calomel electrode was used as the reference electrode , the molar concentration is 0.1mol/L～1mol/L sulfate aqueous solution as electrolyte, in this way, the nickel foam deposited with graphene is prepared;

(C) Soak the nickel foam deposited with graphene in an aqueous solution of carbon nanotubes with a mass concentration of 0.2 mg/ml to 2 mg/ml, take it out and dry it, so as to prepare a foam with graphene and carbon nanotubes deposited at the same time Nickel, and use it as an electrode of a supercapacitor.

According to a fourth aspect of the present invention, a kind of preparation method of supercapacitor electrode based on nickel foam is provided, it is characterized in that, the method comprises the following steps:

(1) Cleaning the nickel foam, and then immersing it in an aqueous solution of graphene oxide with a mass concentration of 1 mg/ml to 10 mg/ml, thereby obtaining nickel foam deposited with graphene oxide;

(II) Cyclic voltammetric electrochemical deposition was performed on GO-deposited nickel foam by a three-electrode method, in which the GO-deposited nickel foam was used as the working electrode, the platinum electrode was used as the auxiliary electrode, and the saturated calomel electrode was used as the reference Electrode, molar concentration is 0.1mol/L～1mol/L manganese acetate aqueous solution is used as electrolyte, in this way, the foamed nickel with graphene and manganese dioxide deposited simultaneously is prepared, and it is used as the electrode of supercapacitor.

As a further preference, for the above-mentioned cleaning operation of foamed nickel, the specific process is to wash the foamed nickel with glacial acetic acid, acetone, ethanol and deionized water in sequence, and the cleaning time is 5 to 30 minutes.

As a further preference, for the above-mentioned operation of soaking the nickel foam into the graphene oxide aqueous solution, the system temperature is controlled within the range of 40°C to 80°C.

As a further preference, for the above-mentioned operation of performing constant voltage electrochemical reduction using the three-electrode method, the reduction potential is set to -1.5V to +1.0V, and the reduction time is set to 200 seconds to 800 seconds.

As a further preference, for the above-mentioned operation of performing cyclic voltammetric electrochemical deposition using the three-electrode method, the potential range is set to -1.5V to +1.4V, the scan rate is 50mV/s, and the number of cycles is 1 to 3. .

According to the fifth aspect of the present invention, there is also provided an asymmetric supercapacitor product prepared by assembling the above-mentioned positive and negative electrodes. The two electrodes of the asymmetric supercapacitor are laminated with a solid electrolyte and separated by a diaphragm. The electrolyte is composed of a mixture of potassium polyacrylate and potassium chloride, and the diaphragm is selected from polypropylene film, glass fiber or capacitor paper.

As a further preference, under the test conditions of electrochemical constant current charge and discharge, the specific capacitance of the asymmetric supercapacitor is 37.2F/g-69.4F/g, and the energy density is 18.2wh/kg-31.8wh/kg.

According to the sixth aspect of the present invention, there is also provided a use of the supercapacitor assembled with the above-mentioned electrodes in electric vehicles, hybrid vehicles, power supplies of pulse electronic devices, and emergency backup power supplies.

Generally speaking, compared with the prior art, the above technical solution conceived by the present invention mainly has the following technical advantages:

1. By designing the composite type of electrode materials, the respective advantages of these materials can be fully utilized, and capacitor electrodes with high specific capacitance and high energy density can be obtained. Foamed nickel is used as a current collector to facilitate compounding with other materials to make electrode materials. And it is easy to press and process; graphene itself has excellent electrical and mechanical properties and high specific surface area, and when it is combined with carbon nanotubes or transition metal oxides to make electrodes, tests have shown that it can significantly improve the capacitance of supercapacitors. Energy Density;

2. Due to the water-based electrolyte assembly method, the use of various components can be avoided, and electrodes and corresponding supercapacitor products can be produced at low cost and low energy consumption;

3. Through the selection of the positive and negative electrode materials of the asymmetric supercapacitor, the capacitance difference between the two electrode materials can be made to achieve a good match, and the best capacitance characteristics can be exerted in the asymmetric supercapacitor; in addition, through The mixture of potassium polyacrylate and potassium chloride is used as the electrolyte, which can facilitate the assembly of supercapacitors and obtain high energy density;

4. The process according to the present invention is easy to operate, has high preparation efficiency, can effectively reduce raw material costs and production energy consumption, and does not cause environmental pollution, so it is especially suitable for large-scale industrial production.

Description of drawings

Figure 1 is a scanning electron microscope image showing nickel foam deposited with graphene oxide;

Figure 2 is a scanning electron microscope image showing nickel foam deposited with graphene and carbon nanotubes simultaneously;

Figure 3 is a scanning electron microscope image showing nickel foam deposited with graphene and manganese dioxide;

Fig. 4 is the cyclic voltammogram of the nickel foam electrode deposited with graphene at different scan rates;

Figure 5 is a schematic diagram of the charge and discharge of a nickel foam electrode deposited with graphene (shown in dotted line) and a nickel foam electrode deposited with graphene and carbon nanotubes (shown in solid line) at a current density of 1A/g;

Figure 6 is a nickel foam electrode (shown by dotted line) deposited with graphene and carbon nanotubes at the same time, and a nickel foam electrode (shown by solid line) deposited with graphene and manganese dioxide at the same time when the scan rate is 50mV/s The cyclic voltammogram;

Fig. 7 is the cyclic voltammogram of the asymmetric supercapacitor prepared according to the present invention at different scan rates;

Fig. 8 is an optical photograph showing an asymmetric supercapacitor prepared according to the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

As mentioned above, in view of the deficiencies in the preparation process of various types of supercapacitor electrodes in the prior art, the present invention provides a variety of new supercapacitors by studying the electrode composite materials of supercapacitors and their preparation processes. The preparation method of the electrode, correspondingly, can give full play to the high specific capacitance characteristics of these composite materials, and further increase the energy density of the supercapacitor; in addition, by adopting the method of assembly of the aqueous electrolyte, the use of various components can be avoided, and the corresponding can be Electrode and supercapacitor products are produced in a manner of easy manipulation, low cost and low energy consumption.

Specifically, for the electrode preparation process of an asymmetric supercapacitor, the preparation method proposed by the present invention mainly includes the following steps:

First, the nickel foam is cleaned, and then soaked in an aqueous solution of graphene oxide with a mass concentration of 1 mg/ml to 10 mg/ml, thereby obtaining nickel foam deposited with graphene oxide;

Then, the nickel foam deposited with graphene oxide is used as the precursor material to make the positive and negative electrodes of the asymmetric supercapacitor respectively. The specific process is as follows:

The three-electrode method is used to perform constant voltage electrochemical reduction on the precursor material, wherein the nickel foam deposited with graphene oxide is used as the working electrode, the platinum electrode is used as the auxiliary electrode, and the saturated calomel electrode is used as the reference electrode, and the molar concentration is 0.1mol /L～1mol/L sulfate aqueous solution is used as the electrolyte, and the nickel foam deposited with graphene is prepared in this way; then the nickel foam electrode deposited with graphene is soaked to a mass concentration of 0.2mg/ml～2mg/ml The carbon nanotube aqueous solution is taken out and dried, thereby making nickel foam with carbon nanotubes and graphene deposited at the same time, and using it as the negative electrode of an asymmetric supercapacitor;

At the same time, a three-electrode method was used to perform cyclic voltammetry electrochemical deposition on the precursor material, wherein nickel foam deposited with graphene oxide was used as a working electrode, a platinum electrode was used as an auxiliary electrode, and a saturated calomel electrode was used as a reference electrode. An aqueous manganese acetate solution with a molar concentration of 0.1mol/L to 1mol/L is used as an electrolyte, and nickel foam with manganese dioxide and graphene deposited simultaneously is prepared in this way, and it is used as the positive electrode of an asymmetric supercapacitor.

Finally, the positive and negative electrodes prepared by the above method or other appropriate methods can be passed through a solid electrolyte composed of a mixture of potassium polyacrylate and potassium chloride and a separator selected from polypropylene film, glass fiber or capacitor paper. Assembled to obtain the final asymmetric supercapacitor product.

For the electrodes of electric double layer capacitors or Faraday quasi-capacitors, the electrode materials can be made of graphene/nickel foam, graphene/carbon nanotubes/nickel foam or graphene/manganese dioxide/nickel foam respectively, depending on It depends on the specific type of supercapacitor and its energy storage mechanism.

Correspondingly, its preparation method can adopt the following steps:

Option One:

First, the nickel foam is cleaned, and then soaked in an aqueous solution of graphene oxide with a mass concentration of 1 mg/ml to 10 mg/ml, thereby obtaining nickel foam deposited with graphene oxide;

Next, constant-voltage electrochemical reduction was performed on the nickel foam deposited with graphene oxide by a three-electrode method, in which the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the auxiliary electrode, and the saturated calomel electrode was used as the reference electrode. A sulfate solution with a molar concentration of 0.1 mol/L to 1 mol/L is used as an electrolyte to prepare graphene-deposited nickel foam and use it as an electrode of a supercapacitor.

Option II:

First, the nickel foam is cleaned, and then soaked in an aqueous solution of graphene oxide with a mass concentration of 1 mg/ml to 10 mg/ml, thereby obtaining nickel foam deposited with graphene oxide;

Next, constant-voltage electrochemical reduction was performed on the nickel foam deposited with graphene oxide by a three-electrode method, in which the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the auxiliary electrode, and the saturated calomel electrode was used as the reference electrode. Aqueous sulfate solution with a molar concentration of 0.1mol/L to 1mol/L is used as an electrolyte to prepare nickel foam deposited with graphene in this way;

Finally, soak the nickel foam electrode deposited with graphene into an aqueous solution of carbon nanotubes with a mass concentration of 0.2 mg/ml to 2 mg/ml and take it out to dry, thus making a foam with graphene and carbon nanotubes deposited at the same time Nickel, and use it as an electrode of a supercapacitor.

third solution:

First, the nickel foam is cleaned, and then soaked in an aqueous solution of graphene oxide with a mass concentration of 1 mg/ml to 10 mg/ml, thereby obtaining nickel foam deposited with graphene oxide;

Next, cyclic voltammetric electrochemical deposition was performed on the nickel foam deposited with graphene oxide by a three-electrode method, in which the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the auxiliary electrode, and the saturated calomel electrode was used as the reference electrode Manganese acetate aqueous solution with a molar concentration of 0.1mol/L to 1mol/L is used as an electrolyte to prepare nickel foam with graphene and manganese dioxide deposited simultaneously, and use it as an electrode of a supercapacitor.

Some specific examples of the present invention will be given below in order to further explain the mechanism and preparation process of the present invention, wherein the reagents and raw materials used can be obtained from commercial sources.

Example 1

Cut the nickel foam into a suitable size and wash it with glacial acetic acid, acetone, ethanol and deionized water for 10 minutes. Then soak the cleaned nickel foam into a graphene oxide solution with a concentration of 5 mg/mL, and the temperature of the system is controlled at 80 degrees. After about 10 minutes, take out the nickel foam and dry it, and its scanning electron microscope picture can be referred to in Figure 1.

The nickel foam deposited with graphene oxide was subjected to constant voltage electrochemical reduction with a three-electrode method, the reduction potential was -1.5V, and the reduction time was 600s, and the nickel foam electrode deposited with graphene was obtained. In this process, the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the counter electrode, the saturated calomel electrode was used as the reference electrode, and 0.5 mol/L sodium sulfate solution was used as the electrolyte. Next, soak the nickel foam deposited with graphene into the carbon nanotube dispersion with a concentration of 1 mg/mL, then immediately take it out and dry it. The nickel foam negative electrode of graphene, its specific scanning electron microscope picture can refer to accompanying drawing 2.

The nickel foam deposited with graphene oxide was subjected to cyclic voltammetry electrochemical deposition of manganese dioxide and reduced graphene oxide with a three-electrode method. The potential interval was -1.5V, the sweep rate was 50mV/s, and the number of cycles was 1. That is, a nickel foam electrode deposited with manganese dioxide and graphene is obtained. In this process, the nickel foam deposited with graphene oxide is used as the working electrode, the platinum electrode is used as the counter electrode, the saturated calomel electrode is used as the reference electrode, and the manganese acetate solution of 0.5mol/L is used as the electrolyte, and dried Afterwards, the positive electrode is produced, and its specific scanning electron microscope picture can be referred to accompanying drawing 3.

Take two pieces of positive and negative electrodes prepared above and soak them in the mixed solution of potassium polyacrylate and potassium chloride of appropriate concentration for a certain period of time, take them out and glue them together, and use a material selected from polypropylene film, glass fiber or capacitor paper in the middle. septum separated. After the moisture in the potassium polyacrylate evaporates completely, it is packaged to make the desired asymmetric supercapacitor product (see Figure 8 for details)

Example 2

Cut the nickel foam into a suitable size and wash it with glacial acetic acid, acetone, ethanol and deionized water for 10 minutes. Then soak the cleaned nickel foam into a graphene oxide solution with a concentration of 1 mg/mL, and the temperature of the system is controlled at 40 degrees. After about 30 minutes, take out the nickel foam and dry it.

The nickel foam deposited with graphene oxide was subjected to constant voltage electrochemical reduction with a three-electrode method, the reduction potential was -1.0V, and the reduction time was 800s, and the nickel foam electrode deposited with graphene was prepared. In this process, the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the counter electrode, the saturated calomel electrode was used as the reference electrode, and 1 mol/L sodium sulfate solution was used as the electrolyte. Next, soak the nickel foam deposited with graphene into the carbon nanotube dispersion with a concentration of 0.2 mg/mL, then take it out and dry immediately. The soaking-drying process is carried out twice to obtain a carbon nanotube and graphene-based nickel foam electrodes.

The nickel foam deposited with graphene oxide was subjected to cyclic voltammetry electrochemical deposition of manganese dioxide and reduced graphene oxide with a three-electrode method. The potential interval was -1.0V, the sweep rate was 50mV/s, and the number of cycles was 2. That is, a nickel foam electrode deposited with manganese dioxide and graphene is obtained. In this process, the nickel foam deposited with graphene oxide is used as the working electrode, the platinum electrode is used as the counter electrode, the saturated calomel electrode is used as the reference electrode, and the manganese acetate solution of 1mol/L is used as the electrolyte. That is, a positive electrode was prepared.

Take two pieces of positive and negative electrodes prepared above and soak them in the mixed solution of potassium polyacrylate and potassium chloride of appropriate concentration for a certain period of time, take them out and glue them together, and use a material selected from polypropylene film, glass fiber or capacitor paper in the middle. septum separated. After the moisture in the potassium polyacrylate is completely volatilized, it is packaged to produce the desired asymmetric supercapacitor product.

Example 3

Cut the nickel foam into a suitable size and wash it with glacial acetic acid, acetone, ethanol and deionized water for 10 minutes. Then soak the cleaned nickel foam into a graphene oxide solution with a concentration of 10 mg/mL, and the temperature of the system is controlled at 60 degrees. After about 15 minutes, take out the nickel foam and dry it.

The nickel foam deposited with graphene oxide was subjected to constant voltage electrochemical reduction with a three-electrode method, the reduction potential was 1.0 V, and the reduction time was 200 s, so that the nickel foam electrode deposited with graphene was prepared. In this process, the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the counter electrode, the saturated calomel electrode was used as the reference electrode, and 0.1 mol/L sodium sulfate solution was used as the electrolyte. Next, soak the nickel foam deposited with graphene into a concentration of 2mg/mL carbon nanotube dispersion, then immediately take it out and dry it. Graphene-based nickel foam electrodes.

The nickel foam deposited with graphene oxide was subjected to cyclic voltammetry electrochemical deposition of manganese dioxide and reduced graphene oxide by the three-electrode method, the potential interval was 1.4V, the sweep rate was 50mV/s, and the number of cycles was 3, that is A nickel foam electrode deposited with manganese dioxide and graphene was prepared. In this process, the nickel foam deposited with graphene oxide is used as the working electrode, the platinum electrode is used as the counter electrode, the saturated calomel electrode is used as the reference electrode, and the manganese acetate solution of 0.1mol/L is used as the electrolyte, and dried After that, the positive electrode was prepared.

Take two pieces of positive and negative electrodes prepared above and soak them in the mixed solution of potassium polyacrylate and potassium chloride of appropriate concentration for a certain period of time, take them out and glue them together, and use a material selected from polypropylene film, glass fiber or capacitor paper in the middle. septum separated. After the moisture in the potassium polyacrylate is completely volatilized, it is packaged to produce the desired asymmetric supercapacitor product.

Example 4

Cut the nickel foam into a suitable size and wash it with glacial acetic acid, acetone, ethanol and deionized water for 10 minutes. Then soak the cleaned nickel foam into a graphene oxide solution with a concentration of 5 mg/mL, and the temperature of the system is controlled at 80 degrees. After about 5 minutes, take out the nickel foam and dry it.

The nickel foam deposited with graphene oxide was subjected to constant voltage electrochemical reduction by the three-electrode method. In this process, the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the counter electrode, and the saturated calomel electrode was As the reference electrode, use 0.3mol/L sodium sulfate solution as the electrolyte. The reduction potential is -1.5V, and the reduction time is 200s, that is, a nickel foam electrode deposited with graphene is prepared.

Example 5

Cut the nickel foam into a suitable size and wash it with glacial acetic acid, acetone, ethanol and deionized water for 10 minutes. Then soak the cleaned nickel foam into a graphene oxide solution with a concentration of 10 mg/mL, and the temperature of the system is controlled at 80 degrees. After about 5 minutes, take out the nickel foam and dry it.

The nickel foam deposited with graphene oxide was subjected to constant voltage electrochemical reduction by the three-electrode method. In this process, the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the counter electrode, and the saturated calomel electrode was As the reference electrode, use 1mol/L sodium sulfate solution as the electrolyte. The reduction potential is -1.0V, and the reduction time is 400s, that is, a nickel foam electrode deposited with graphene is prepared.

Example 6

Cut the nickel foam into a suitable size and wash it with glacial acetic acid, acetone, ethanol and deionized water for 10 minutes. Then soak the cleaned nickel foam into a graphene oxide solution with a concentration of 1 mg/mL, and the temperature of the system is controlled at 40 degrees. After about 30 minutes, take out the nickel foam and dry it.

The nickel foam deposited with graphene oxide was subjected to constant voltage electrochemical reduction by the three-electrode method. In this process, the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the counter electrode, and the saturated calomel electrode was As the reference electrode, use 0.1mol/L sodium sulfate solution as the electrolyte. The reduction potential is 1.0V, and the reduction time is 200s, that is, a nickel foam electrode deposited with graphene is prepared.

Example 7

Cut the nickel foam into a suitable size and wash it with glacial acetic acid, acetone, ethanol and deionized water for 8 minutes. Then soak the cleaned nickel foam into a graphene oxide solution with a concentration of 1 mg/mL, and the temperature of the system is controlled at 40 degrees. After about 30 minutes, take out the nickel foam and dry it.

The nickel foam deposited with graphene oxide was subjected to constant voltage electrochemical reduction by the three-electrode method. In this process, the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the counter electrode, and the saturated calomel electrode was As the reference electrode, use 0.1mol/L sodium sulfate solution as the electrolyte. The reduction potential is -1.5V, and the reduction time is 600s, that is, the nickel foam deposited with graphene is obtained.

The nickel foam deposited with graphene was soaked in an aqueous solution of carbon nanotubes with a mass concentration of 2 mg/ml, taken out and dried, thereby preparing a nickel foam electrode deposited with graphene and carbon nanotubes at the same time.

Example 8

Cut the nickel foam into a suitable size and wash it with glacial acetic acid, acetone, ethanol and deionized water for 10 minutes. Then soak the cleaned nickel foam into the graphene oxide solution with a concentration of 4 mg/mL, and the temperature of the system is controlled at 80 degrees. After about 5 minutes, take out the nickel foam and dry it.

The nickel foam deposited with graphene oxide was subjected to constant voltage electrochemical reduction by the three-electrode method. In this process, the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the counter electrode, and the saturated calomel electrode was As the reference electrode, use 0.6mol/L sodium sulfate solution as the electrolyte. The reduction potential is -1.0V, and the reduction time is 400s, that is, the nickel foam deposited with graphene is obtained.

The nickel foam deposited with graphene was soaked in an aqueous solution of carbon nanotubes with a mass concentration of 0.2 mg/ml, taken out and dried, thereby preparing a nickel foam electrode deposited with graphene and carbon nanotubes at the same time.

Example 9

Cut the nickel foam into a suitable size and wash it with glacial acetic acid, acetone, ethanol and deionized water for 10 minutes. Then soak the cleaned nickel foam into a graphene oxide solution with a concentration of 10 mg/mL, and the temperature of the system is controlled at 60 degrees. After about 10 minutes, take out the nickel foam and dry it.

The nickel foam deposited with graphene oxide was subjected to constant voltage electrochemical reduction by the three-electrode method. In this process, the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the counter electrode, and the saturated calomel electrode was As the reference electrode, use 1mol/L sodium sulfate solution as the electrolyte. The reduction potential is 1.0V, and the reduction time is 200s, that is, the nickel foam deposited with graphene is obtained.

The nickel foam deposited with graphene was immersed in an aqueous solution of carbon nanotubes with a mass concentration of 1.5 mg/ml, taken out and dried, thereby preparing a nickel foam electrode deposited with graphene and carbon nanotubes at the same time.

Example 10

Cut the nickel foam into a suitable size and wash it with glacial acetic acid, acetone, ethanol and deionized water for 10 minutes. Then soak the cleaned nickel foam into a graphene oxide solution with a concentration of 1 mg/mL, and the temperature of the system is controlled at 40 degrees. After about 30 minutes, take out the nickel foam and dry it.

The nickel foam deposited with graphene oxide was subjected to cyclic voltammetry electrochemical deposition of manganese dioxide and reduced graphene oxide with a three-electrode method. The potential range was -1.5V, the sweep rate was 50mV/s, and the number of cycles was 2. That is, a nickel foam electrode deposited with manganese dioxide and graphene is obtained. In this process, the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the counter electrode, the saturated calomel electrode was used as the reference electrode, and 1mol/L manganese acetate solution was used as the electrolyte. obtain the desired supercapacitor electrodes.

Example 11

Cut the nickel foam into a suitable size and wash it with glacial acetic acid, acetone, ethanol and deionized water for 10 minutes. Then soak the cleaned nickel foam into the graphene oxide solution with a concentration of 4 mg/mL, and the temperature of the system is controlled at 80 degrees. After about 5 minutes, take out the nickel foam and dry it.

The nickel foam deposited with graphene oxide was subjected to cyclic voltammetry electrochemical deposition of manganese dioxide and reduced graphene oxide with a three-electrode method. The potential interval was 1.4V, the sweep rate was 50mV/s, and the number of cycles was 1, that is A nickel foam electrode deposited with manganese dioxide and graphene was prepared. In this process, the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the counter electrode, the saturated calomel electrode was used as the reference electrode, and 0.1mol/L manganese acetate solution was used as the electrolyte. The required supercapacitor electrodes are prepared.

Example 12

Cut the nickel foam into a suitable size and wash it with glacial acetic acid, acetone, ethanol and deionized water for 10 minutes. Then soak the cleaned nickel foam into a graphene oxide solution with a concentration of 10 mg/mL, and the temperature of the system is controlled at 60 degrees. After about 15 minutes, take out the nickel foam and dry it.

The nickel foam deposited with graphene oxide was subjected to cyclic voltammetry electrochemical deposition of manganese dioxide and reduced graphene oxide with a three-electrode method, the potential interval was 1.0V, the sweep rate was 50mV/s, and the number of cycles was 3, that is A nickel foam electrode deposited with manganese dioxide and graphene was prepared. In this process, the nickel foam deposited with graphene oxide was used as the working electrode, the platinum electrode was used as the counter electrode, the saturated calomel electrode was used as the reference electrode, and 0.65mol/L manganese acetate solution was used as the electrolyte. The required supercapacitor electrodes are prepared.

Taking the asymmetric supercapacitor sample prepared in Example 1 as an example, it performs a cycle test at different scan rates, and the test results are shown in Figure 7. The test results of the samples prepared in Examples 2 and 3 are similar to this . It can be seen from Figure 7 that the potential window of the asymmetric supercapacitor is 0-1.8V, and the cyclic voltammetry curves at different scan rates are approximately rectangular and have relatively good symmetry. /s) There is no obvious deformation in the graph, indicating that the asymmetric supercapacitor has good electrochemical capacitance characteristics.

Taking the nickel foam electrode deposited with graphene obtained in embodiment 4 as an example, it performs a cycle test at different scan rates, and Fig. 4 shows a cyclic voltammogram as a result of the test, and the results of embodiment 5 and 6 The test results were similar to this. It can be seen from Figure 4 that the cyclic voltammetry curves at different scan rates are close to a rectangle, which proves that the nickel foam electrode deposited with graphene has ideal electric double layer capacitance characteristics.

Taking the electrode samples prepared in Example 4 and Example 7 as examples, a charge-discharge test with a current density of 1A/g was performed on them, and the specific test results are shown in FIG. 5 . The test results of other embodiments such as 5,6 and 8,9 are similar to this. It can be seen from Figure 5 that the single charge and discharge curves of the two electrodes are approximately triangular and have relatively good symmetry, and their voltage changes linearly with time, indicating that the electrodes have good charge and discharge reversibility, but the deposition of graphene and The charge and discharge time of the nickel foam electrode deposited with carbon nanotubes is significantly longer than that of the nickel foam electrode deposited with graphene, indicating that the nickel foam electrode deposited with graphene and carbon nanotubes has a higher capacitance due to the introduction of carbon nanotubes.

Taking the electrode samples prepared in Example 8 and Example 10 as examples, a cycle test with a scan rate of 50 mV/s was performed on them, and the specific test results are shown in FIG. 6 . The test results of other embodiments such as 7,9 and embodiment 11,12 are similar to this. It can be seen from Figure 6 that the potential window of the nickel foam electrode deposited with graphene and manganese dioxide is 0-0.8V, and the potential window of the nickel foam electrode deposited with graphene and carbon nanotubes is -0.8-0.2V , and the cyclic voltammogram areas of the two electrodes are not very different, so they can be matched better, and the nickel foam electrode deposited with graphene and manganese dioxide is used as the positive electrode and the electrode deposited with graphene and carbon nanotubes is realized. Preparation of a nickel foam electrode as negative electrode for asymmetric supercapacitors.

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (13)

1., based on a preparation method for the Asymmetric Supercapacitor electrode of nickel foam, it is characterized in that, the method comprises the following steps:

A nickel foam is cleaned by (), being then dipped into mass concentration is in the graphene oxide water solution of 1mg/ml ~ 10mg/ml, obtains the nickel foam depositing graphene oxide thus;

B (), to deposit the nickel foam of graphene oxide for persursor material, makes the both positive and negative polarity of Asymmetric Supercapacitor respectively, its process is specially:

(b1) three-electrode method is adopted to perform constant voltage electrochemical reduction to described persursor material, wherein using the nickel foam of deposited oxide Graphene as work electrode, platinum electrode is as auxiliary electrode, saturated calomel electrode is as reference electrode, molar concentration be the sulfate solution of 0.1mol/L ~ 1mol/L as electrolyte, the obtained nickel foam depositing Graphene in this way; Then the foam nickel electrode this being deposited Graphene is dipped into mass concentration to be in the carbon nano-tube aqueous solutions of 0.2mg/ml ~ 2mg/ml and to take out drying, the obtained nickel foam simultaneously depositing carbon nano-tube and Graphene thus, and it can be used as the negative pole of Asymmetric Supercapacitor;

(b2) three-electrode method is adopted to perform cyclic voltammetric electrochemical deposition to described persursor material, wherein using the nickel foam of deposited oxide Graphene as work electrode, platinum electrode is as auxiliary electrode, saturated calomel electrode is as reference electrode, molar concentration is that the manganese acetate aqueous solution of 0.1mol/L ~ 1mol/L is as electrolyte, the obtained nickel foam simultaneously depositing manganese dioxide and Graphene in this way, and it can be used as the positive pole of Asymmetric Supercapacitor.

2. preparation method as claimed in claim 1, it is characterized in that, for the operation of above-mentioned cleaning nickel foam, its detailed process is for clean nickel foam with glacial acetic acid, acetone, ethanol and deionized water successively, and scavenging period is 5 ~ 30 minutes.

3. preparation method as claimed in claim 1, it is characterized in that, for above-mentioned operation nickel foam being dipped into graphene oxide water solution, its system temperature is controlled as the scope of 40 DEG C ~ 80 DEG C.

4. preparation method as claimed in claim 1, is characterized in that, above-mentioned employing three-electrode method is performed to the operation of constant voltage electrochemical reduction, reduction potential is set to-1.5V ~+1.0V, and the recovery time is set to 200 seconds ~ 800 seconds.

5. preparation method as claimed in claim 1, is characterized in that, above-mentioned employing three-electrode method is performed to the operation of cyclic voltammetric electrochemical deposition, potential region is set to-1.5V ~+1.4V, sweeps speed for 50mV/s, and the circulation number of turns is 1 ~ 3 circle.

6. based on a preparation method for the electrode of super capacitor of nickel foam, it is characterized in that, the method comprises the following steps:

(A) nickel foam cleaned, being then dipped into mass concentration is in the graphene oxide water solution of 1mg/ml ~ 10mg/ml, obtains the nickel foam depositing graphene oxide thus;

(B) three-electrode method is adopted to perform constant voltage electrochemical reduction to the nickel foam depositing graphene oxide, wherein using the nickel foam of deposited oxide Graphene as work electrode, platinum electrode is as auxiliary electrode, saturated calomel electrode is as reference electrode, molar concentration be the sulfate solution of 0.1mol/L ~ 1mol/L as electrolyte, the obtained nickel foam depositing Graphene in this way;

(C) nickel foam this being deposited Graphene is dipped into mass concentration to be in the carbon nano-tube aqueous solutions of 0.2mg/ml ~ 2mg/ml and to take out drying, the obtained nickel foam simultaneously depositing Graphene and carbon nano-tube thus, and it can be used as the electrode of ultracapacitor.

7. preparation method as claimed in claim 6, it is characterized in that, for above-mentioned operation nickel foam being dipped into graphene oxide water solution, its system temperature is controlled as the scope of 40 DEG C ~ 80 DEG C.

8. preparation method as claimed in claim 6, is characterized in that, above-mentioned employing three-electrode method is performed to the operation of constant voltage electrochemical reduction, reduction potential is set to-1.5V ~+1.0V, and the recovery time is set to 200 seconds ~ 800 seconds.

9. based on a preparation method for the electrode of super capacitor of nickel foam, it is characterized in that, the method comprises the following steps:

(I) nickel foam cleaned, being then dipped into mass concentration is in the graphene oxide water solution of 1mg/ml ~ 10mg/ml, obtains the nickel foam depositing graphene oxide thus;

(II) three-electrode method is adopted to perform cyclic voltammetric electrochemical deposition to the nickel foam depositing graphene oxide, wherein using the nickel foam of deposited oxide Graphene as work electrode, platinum electrode is as auxiliary electrode, saturated calomel electrode is as reference electrode, molar concentration is that the manganese acetate aqueous solution of 0.1mol/L ~ 1mol/L is as electrolyte, the obtained nickel foam simultaneously depositing Graphene and manganese dioxide in this way, and it can be used as the electrode of ultracapacitor.

10. preparation method as claimed in claim 9, it is characterized in that, for above-mentioned operation nickel foam being dipped into graphene oxide water solution, its system temperature is controlled as the scope of 40 DEG C ~ 80 DEG C.

11. preparation methods as claimed in claim 9, is characterized in that, above-mentioned employing three-electrode method is performed to the operation of cyclic voltammetric electrochemical deposition, potential region is set to-1.5V ~+1.4V, sweep speed for 50mV/s, and the circulation number of turns is 1 ~ 3 circle.

12. 1 kinds of Asymmetric Supercapacitors, it is characterized in that, the negative pole of this ultracapacitor is made up of the nickel foam depositing carbon nano-tube and Graphene simultaneously, positive pole is made up of the nickel foam depositing manganese dioxide and Graphene simultaneously, give superimposed by solid electrolyte between two electrodes and separate with barrier film, described electrolyte is made up of the mixed liquor of polyacrylic acid potassium and potassium chloride, and described barrier film is selected from polypropylene screen, glass fibre or kraft capacitor paper.

13. Asymmetric Supercapacitors as claimed in claim 12, is characterized in that, under the test condition of electrochemistry constant current charge-discharge, the ratio capacitance of this Asymmetric Supercapacitor is 37.2F/g ~ 69.4F/g, and energy density is 18.2wh/kg-31.8wh/kg.