CN101527202A - Oxidized grapheme/polyaniline super capacitor composite electrode material and preparation method and application thereof - Google Patents

Abstract

The invention discloses a graphene oxide/polyaniline supercapacitor composite electrode material and its preparation method and application. Firstly, graphite oxide is added to water for ultrasonic dispersion to form a graphene oxide solution uniformly dispersed in a single layer; at room temperature, Add aniline dropwise to the obtained graphene oxide solution, and continue to ultrasonically disperse to form a mixed solution; under low temperature conditions, successively add hydrogen peroxide, ferric chloride and hydrochloric acid solution to the mixed solution, stir and polymerize; after the reaction is completed, the The obtained mixed solution is centrifuged, washed, and vacuum-dried to obtain a graphene oxide/polyaniline composite electrode material, and the graphene oxide/polyaniline composite material is used as an electrode material for a supercapacitor or a battery power storage system. The present invention obtains the graphene oxide/polyaniline composite electrode material with excellent electrochemical performance through the preparation method, which greatly improves the specific capacity of graphene oxide and polyaniline, and the addition of graphene oxide improves the charging and discharging of polyaniline life.

Description

Graphene oxide/polyaniline supercapacitor composite electrode material and its preparation method and application

technical field

The invention belongs to organic and inorganic composite materials, in particular to a graphene oxide/polyaniline supercapacitor composite electrode material and a preparation method thereof.

Background technique

Supercapacitors have huge application value and market potential in automobiles, electric power, railways, communications, national defense, consumer electronics, etc., and have been widely concerned by countries all over the world. But there has been a bottleneck in the production of high-performance electrode materials, the core part of supercapacitors. Most of the current ultracapacitor products are cheap carbon materials based on the electric double layer capacitor power storage mechanism. It is very difficult to increase their power density and energy density on this basis; are greatly restricted. Conductive polyaniline, which stores charges based on pseudocapacitive redox reactions, has high energy density, but its ion doping/dedoping will cause the volume of its membrane to expand/shrink, crack the membrane, and eventually lead to electrode materials. Decreased electrical performance, short charge and discharge cycle life, poor stability, affecting its utilization rate, etc. For this reason, compounding carbon materials and polyaniline has become one of the ways to excavate new materials with high performance electrodes, such as conductive polyaniline/carbon nanotubes (Mi, H. et al., Microwave-Assisted Synthesis and Electrochemical Capacitance of Polyaniline/ Multi-Wall Carbon Nanotubes Composite.Electrochem.Commun.2007, 9, 2859-2862; Deng Meigen et al., Chinese invention patent CN 1887965A), polyaniline/activated carbon (Wang Qin et al., research on polyaniline/activated carbon composite electrodes for supercapacitors. The electrochemical properties of composite materials such as new carbon materials. 2008, 23, 275-280) have been greatly improved. Although the specific surface area of activated carbon is large, due to its poor conductivity, the performance of the composite material is not significantly improved; the high preparation cost of carbon nanotubes also greatly limits its application performance.

Graphene is a two-dimensional graphite nanosheet with a thickness of one atom. It has many unique physical and chemical properties, such as a large specific surface area, excellent electrical conductivity, thermal conductivity, and mechanical properties, and has quickly attracted widespread attention. It is the thinnest known material, yet the hardest and toughest. Its oxide, graphene oxide, also has unique physical and chemical properties. The "graphene oxide" paper prepared by American scientists is a new type of paper-like material with high strength, strong flexibility and light weight (Dmitriy A.Dikin et al. Preparation and characterization of graphene oxide paper.Nature 2007, 448, 457-460), this new material can be used as electrolyte or hydrogen storage material for fuel cells, electrodes for supercapacitors and batteries, ultra-thin chemical filters, and can also be used with Polymers etc. are mixed to produce new materials. Introduce graphene-like materials into composite materials (such as the first polymer/graphene composite, SashaStankovich et al.Graphene-based composite materials.Nature 2006, 442, 282-286), using its special two-dimensional nanostructure , ultra-high surface area, excellent electrical conductivity, super mechanical properties and other advantages, some new functional composite materials can be prepared, and the application fields of new carbon-based materials can be opened up.

Contents of the invention

The object of the present invention is to provide a graphene oxide/polyaniline composite electrode material for energy storage devices such as supercapacitors and a preparation method thereof, which can increase the specific capacity of polyaniline and prolong its charge and discharge life.

The technical solution to realize the object of the present invention is: a kind of graphene oxide/polyaniline supercapacitor composite electrode material is prepared by the following steps:

(1) adding graphite oxide to water for ultrasonic dispersion to form a graphene oxide solution uniformly dispersed in a single sheet;

(2) At room temperature, add aniline dropwise to the obtained graphene oxide solution, and continue ultrasonic dispersion to form a mixed solution;

(3) Under low temperature conditions, hydrogen peroxide, ferric chloride and hydrochloric acid solution are successively added dropwise to the mixed solution, and the mixture is stirred and polymerized;

(4) After the reaction is completed, the obtained mixed solution is centrifuged, washed, and vacuum-dried to obtain a graphene oxide/polyaniline composite electrode material.

A preparation method of graphene oxide/polyaniline supercapacitor composite electrode material, the steps are as follows:

(1) adding graphite oxide to water for ultrasonic dispersion to form a graphene oxide solution uniformly dispersed in a single sheet;

(2) At room temperature, add aniline dropwise to the obtained graphene oxide solution, and continue ultrasonic dispersion to form a mixed solution;

(3) Under low temperature conditions, hydrogen peroxide, ferric chloride and hydrochloric acid solution are successively added dropwise in the mixed solution, after constant volume, the concentrations of aniline and hydrogen peroxide are equal, and the mixture is stirred and polymerized;

(4) After the reaction is completed, the obtained mixed solution is centrifuged, washed, and vacuum-dried to obtain a graphene oxide/polyaniline composite electrode material.

A kind of application of graphene oxide/polyaniline supercapacitor composite electrode material, the graphene oxide/polyaniline composite material is used as the electrode material of the electricity storage system of supercapacitor and battery.

Compared with the prior art, the present invention has significant advantages: (1) make full use of the ultra-large specific surface area of graphene oxide that exists stably in the form of a monolithic layer to improve the electric double layer capacitance of the compound; (2) utilize the graphene oxide surface Oxygen-containing groups such as carboxyl groups form binding sites, and through chemical doping of carboxylic acid groups, as well as a large number of hydrogen bonds and π-π stacking interactions between the two components, graphene oxide is organically combined with the polyaniline skeleton Together, a graphene oxide/polyaniline nanocomposite material is formed, and the synergistic effect between the components makes the supercapacitive performance of the composite electrode material greatly improved, especially in terms of specific capacity and charge-discharge cycle life; (3) using graphene oxide excellent The mechanical properties of the composite electrode material improve the charge-discharge cycle life; (4) one-step in-situ doping polymerization realizes the uniform dispersion of monolithic graphene oxide and polyaniline materials, and graphene oxide also acts as a nanometer during the polymerization process. The template role of fiber assembly; (5) The preparation method of one-step in-situ doping polymerization is simple and easy to operate. Compared with other carbon materials/polyaniline composites, its production cost is lower than that of carbon nanotubes or carbon fiber composites, and it is cheaper than activated carbon The performance of the composite material is superior; (6) the composite prepared by applying the present invention combines the characteristics of graphene oxide, polyaniline and nanomaterials, and has good application prospects and economic benefits in the field of supercapacitors and other energy electrode materials .

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Description of drawings

Figure 1 is the TEM (a) and IR (b) images of the graphene oxide/polyaniline composite electrode material prepared in Example 1 of the present invention with a mass ratio of graphite oxide to aniline (GO:ANI) of 1:100.

Fig. 2 is the graphene oxide/polyaniline composite electrode material prepared in Example 1 of the present invention with a mass ratio of graphite oxide to aniline (GO:ANI) of 1:100 at different current densities.

Fig. 3 is a cyclic voltammogram at 10 mV/S of composite electrode materials with different mass ratios of graphite oxide and aniline prepared in Examples 1-5 of the present invention.

Detailed ways

Graphene oxide/polyaniline supercapacitor composite electrode material and preparation method thereof of the present invention, the steps are as follows:

(1) Add graphite oxide to water for ultrasonic dispersion to form a graphene oxide solution uniformly dispersed in a single layer; the ultrasonic time is 20 to 120 minutes.

(2) At room temperature, add aniline dropwise to the obtained graphene oxide solution, and continue ultrasonic dispersion to form a mixed solution; the ultrasonic time is 10-60 min.

(3) Under low temperature conditions, hydrogen peroxide, ferric chloride and hydrochloric acid solution are successively added dropwise to the mixed liquid, and stirred for polymerization; the reaction temperature is 0-20° C., and the stirred polymerization time is 4-24 hours.

(4) After the reaction is completed, the obtained mixed solution is centrifuged, washed, and vacuum-dried to obtain a graphene oxide/polyaniline composite electrode material.

Wherein, the consumption ratio of water and graphite oxide is 1:1～100:1, the mass ratio of graphite oxide and aniline is 1:10～1:300, and the molar ratio of aniline, hydrogen peroxide, ferric chloride is 300～1000: 300～1000: 1; wherein, the consumption of water, aniline, 30% hydrogen peroxide, 37% hydrochloric acid, 0.1mol/L ferric chloride is in milliliters; the consumption of graphite oxide is in milliliters; milligram meter. The concentrations of aniline and hydrogen peroxide are both between 0.05-0.5 mol/L, and the concentration of hydrochloric acid is between 0.5-1.5 mol/L.

The application of the graphene oxide/polyaniline supercapacitor composite electrode material of the present invention is to use the graphene oxide/polyaniline composite material as the electrode material of the electricity storage system of the supercapacitor and battery.

In the present invention, graphene oxide is added in the aniline polymerization process with hydrogen peroxide as oxidant, ferric chloride as catalyst, and hydrochloric acid as the main doping acid. Heterogeneity, hydrogen bonding and π-π stacking between the two components make graphene oxide and polyaniline skeleton organically combined to form graphene oxide/polyaniline nanocomposites, and the synergistic effect between components The supercapacitive performance of the composite electrode material is greatly improved, especially in terms of improving the specific capacity and cycle life of the polyaniline.

Embodiment 1: the preparation of graphite oxide. Add 10g of phosphorus pentoxide and 10g of potassium persulfate into 30mL of concentrated sulfuric acid at 80°C and stir for 30 minutes, take it out, react at room temperature for 6 hours, filter the product, wash to neutral and dry at room temperature to constant weight. Add the above product into 460mL of concentrated sulfuric acid at 0°C, stir and slowly add potassium permanganate, while controlling the temperature of the system not to exceed 15°C, stir evenly and then raise the temperature to 35±3°C, continue stirring for a certain period of time, and then pour into the system Slowly add 1L of deionized water, control the temperature not to exceed 100°C, and continue stirring for 15 minutes. Add 2.8L of deionized water and 50mL of 30% hydrogen peroxide. After stirring for 5 min, the resulting brown suspension was suction-filtered and dialyzed until there was no sulfate ion in the filtrate. The product was vacuum dried at 60 °C.

(1) Add 18.6mg of graphite oxide to 192.26mL of water, and sonicate for 20-120min. , form a graphene oxide solution uniformly dispersed in a monolithic layer; (2) at room temperature, add 1.86 mL of aniline dropwise to the obtained graphene oxide solution, and disperse with ultrasonic waves for 10 to 60 min to form a mixed solution of 0.1 mol/L aniline; (3) ) at 4°C, add 2.06mL of 30% hydrogen peroxide, 0.4mL of 0.1mol/L ferric chloride and 3.42mL of 37% hydrochloric acid solution dropwise to the mixed solution, the concentration of hydrogen peroxide is 0.1 mol/L, the concentration of hydrochloric acid is 1.5mol/L, stirring and polymerizing for 24h; (4) after the reaction is completed, the obtained mixed solution is centrifuged, washed repeatedly with water and ethanol, and vacuum-dried at 40°C to obtain graphite oxide and aniline mass ratio ( GO:ANI) is a graphene oxide/polyaniline composite electrode material with a ratio of 1:100.

The morphology and structure of the composite were characterized by scanning electron microscopy (SEM) and infrared spectrometer, respectively, and the results are shown in Figure 1 (a and b). TEM showed that the obtained composite was nanofibrous structure. The infrared comparison results of graphite oxide (GO), polyaniline (PANI), and graphene oxide/polyaniline composite electrode materials prove that the characteristic peaks of oxygen-containing groups such as carbonyl and hydroxyl groups of GO are in the graphene oxide/polyaniline composite material. All red-shifted, indicating that graphene oxide and polyaniline skeleton are organically combined through doping and hydrogen bonding forces to form a graphene oxide/polyaniline composite material.

The obtained electrode material, conductive agent (acetylene black) and binder (PTFE) were mixed in proportion and evenly pressed onto the current collector to make an electrode, and the cyclic voltammetry tests of different constant current charge and discharge and 10mV/s scan rate were carried out, and the results As shown in the 1:100 curve in Figure 2 and Figure 3 . The specific capacitance (C, F/g) of a single electrode of a supercapacitor can be calculated according to the charge and discharge formula C=(IΔt)/(mΔE) or C=I)/(mv), where I is the discharge current and Δt is the discharge current Time, m is the mass of the active material on the single electrode, ΔE is the discharge voltage drop excluding the voltage drop interval caused by the equivalent internal resistance (ESR), and v is the voltage scan rate of cyclic voltammetry. The specific capacity of the prepared graphene oxide/polyaniline composite electrode material is 530F/g, while that of polyaniline is 216F/g.

Embodiment 2: the preparation of graphite oxide is the same as embodiment 1.

(1) Add 15.5 mg of graphite oxide to 196.79 mL of water and sonicate for 20-120 min to form a graphene oxide solution uniformly dispersed in a single layer; (2) Add 0.93 mL of aniline dropwise to the obtained graphene oxide solution at room temperature , sonicated for 10 to 60 minutes to disperse and form a mixed solution of 0.05mol/L aniline; (3) at 0°C, add 1.72mL of 30% hydrogen peroxide and 0.33mL of 0.1mol/L trichloro Ferric chloride and 0.23mL of 37% hydrochloric acid solution, the concentration of hydrogen peroxide is 0.083mol/L, the concentration of hydrochloric acid is 0.1mol/L, stirring and polymerizing for 24h; (4) After the reaction is completed, the obtained mixed solution is centrifuged, water, After repeated washing with ethanol, the graphene oxide/polyaniline composite electrode material with a mass ratio of graphite oxide to aniline (GO:ANI) of 1:60 was obtained by vacuum drying at 40°C.

The cyclic voltammetry test results of the prepared graphene oxide/polyaniline composite electrode material at 10 mV/s are shown in the curve of 1:60 in FIG. 3 . The specific capacity of the composite electrode material is 650F/g.

Embodiment 3: the preparation of graphite oxide is the same as embodiment 1.

(1) Add 186.2 mg of graphite oxide to 190.61 mL of water and sonicate for 20 to 120 min to form a graphene oxide solution uniformly dispersed in a single layer; (2) Add 3.73 mL of aniline dropwise to the obtained graphene oxide solution at room temperature , sonicated for 10 to 60 minutes to disperse and form a mixed solution of 0.2mol/L aniline; (3) at 10°C, add 4.12mL of 30% hydrogen peroxide and 0.4mL of 0.1mol/L trichloro Ferric chloride and 1.14mL of 37% hydrochloric acid solution, the concentration of hydrogen peroxide is 0.2mol/L, the concentration of hydrochloric acid is 0.5mol/L, stirred and polymerized for 12h; (4) After the reaction is completed, the obtained mixed solution is centrifuged, washed with water, After repeated washing with ethanol, the graphene oxide/polyaniline composite electrode material with a mass ratio of graphite oxide to aniline (GO:ANI) of 1:20 was obtained by vacuum drying at 40°C.

The cyclic voltammetry test results of the prepared graphene oxide/polyaniline composite electrode material at 10 mV/s are shown in the curve of 1:20 in FIG. 3 . The specific capacity of the composite electrode material is 461F/g.

Embodiment 4: the preparation of graphite oxide is the same as embodiment 1.

(1) Add 372.5mg of graphite oxide to 188.54mL of water, and sonicate for 20-120min. , form a graphene oxide solution uniformly dispersed in a monolithic layer; (2) at room temperature, add 3.73 mL of aniline dropwise to the obtained graphene oxide solution, and disperse by ultrasonication for 10 to 60 min to form a mixed solution of 0.2 mol/L aniline; (3) ) at 20°C, add 4.12mL of 30% hydrogen peroxide, 1.33mL of 0.1mol/L ferric chloride and 2.28mL of 37% hydrochloric acid solution dropwise to the mixed solution, the concentration of hydrogen peroxide is 0.2 mol/L, the concentration of hydrochloric acid is 1.0mol/L, stirring and polymerizing for 4h; (4) after the reaction is completed, the obtained mixed solution is centrifuged, washed repeatedly with water and ethanol, and dried in vacuum at 40°C to obtain graphite oxide and aniline mass ratio ( GO:ANI) is a graphene oxide/polyaniline composite electrode material with a ratio of 1:10.

The cyclic voltammetry test results of the prepared graphene oxide/polyaniline composite electrode material at 10 mV/s are shown in the curve of 1:10 in FIG. 3 . The specific capacity of the composite electrode material is 350F/g.

Embodiment 5: the preparation of graphite oxide is the same as embodiment 1.

(1) Add 31mg of graphite oxide to 176.11mL of water, and sonicate for 20-120min. , form a graphene oxide solution uniformly dispersed in a monolithic layer; (2) at room temperature, add 9.31 mL of aniline dropwise to the obtained graphene oxide solution, and disperse with ultrasonic waves for 10 to 60 min to form a mixed solution of 0.5 mol/L aniline; (3) ) at 15°C, add 10.3mL of 30% hydrogen peroxide, 2.0mL of 0.1mol/L ferric chloride and 2.28mL of 37% hydrochloric acid solution dropwise to the mixed solution, the concentration of hydrogen peroxide is 0.5 mol/L, the concentration of hydrochloric acid is 1.0mol/L, stirring and polymerizing for 24h; (4) after the reaction is completed, the obtained mixed solution is centrifuged, washed repeatedly with water and ethanol, and vacuum-dried at 40°C to obtain graphite oxide and aniline mass ratio ( GO:ANI) is 1:300 graphene oxide/polyaniline composite electrode material.

The cyclic voltammetry test results of the prepared graphene oxide/polyaniline composite electrode material at 10 mV/s are shown in the curve of 1:10 in FIG. 3 . The specific capacity of the composite electrode material is 430F/g.

Claims (8)

1, a kind of graphene oxide/polyaniline super capacitor composite electrode material is characterized in that being got by the following steps preparation:

(1) graphite oxide is added to ultrasonic dispersion in the water, forms with the homodisperse graphene oxide solution of monolithic layer;

(2) under the room temperature, in gained graphene oxide solution, drip aniline, continue ultrasonic dispersion and form mixed liquor;

(3) under cryogenic conditions, in mixed liquor, dropwise add hydrogen peroxide, ferric trichloride and hydrochloric acid solution successively, stir polymerization;

(4) reaction finishes, and the mixed liquor that obtains is centrifugal, washing, vacuum drying obtain graphene oxide/polyaniline composite electrode material.

2, graphene oxide/polyaniline super capacitor composite electrode material according to claim 1, it is characterized in that: the ratio of water and the consumption of graphite oxide 1: 1～100: 1, graphite oxide is 1: 10～1: 300 with the ratio of the quality of aniline, and the ratio of the mole of aniline, hydrogen peroxide, ferric trichloride is 300～1000: 300～1000: 1; Wherein, the consumption of the ferric trichloride of water, aniline, 30% hydrogen peroxide, 37% hydrochloric acid, 0.1mol/L is in milliliter; The consumption of graphite oxide is in milligram.

3, graphene oxide/polyaniline super capacitor composite electrode material according to claim 1 is characterized in that: all between 0.05～0.5mol/L, the concentration of hydrochloric acid is between 0.5～1.5mol/L for the concentration of aniline and hydrogen peroxide.

4, graphene oxide/polyaniline super capacitor composite electrode material according to claim 1 is characterized in that: ultrasonic time is ultrasonic 20～120min in (1) step.

5, graphene oxide/polyaniline super capacitor composite electrode material according to claim 1 is characterized in that: ultrasonic time is ultrasonic 10～60min in (2) step.

6, graphene oxide/polyaniline super capacitor composite electrode material according to claim 1 is characterized in that: reaction temperature is 0～20 ℃ in (3) step, stirs polymerization time 4～24h.

7, a kind of preparation method of graphene oxide/polyaniline super capacitor composite electrode material is characterized in that step is as follows:

(1) graphite oxide is added to ultrasonic dispersion in the water, forms with the homodisperse graphene oxide solution of monolithic layer;

(2) under the room temperature, in gained graphene oxide solution, drip aniline, continue ultrasonic dispersion and form mixed liquor;

(3) under cryogenic conditions, in mixed liquor, dropwise add hydrogen peroxide, ferric trichloride and hydrochloric acid solution successively, make aniline equate behind the constant volume with the concentration of hydrogen peroxide, stir polymerization;

(4) reaction finishes, and the mixed liquor that obtains is centrifugal, washing, vacuum drying obtain graphene oxide/polyaniline composite electrode material.

8, a kind of purposes of graphene oxide/polyaniline super capacitor composite electrode material is characterized in that the electrode material of graphene oxide/polyaniline composite material as the power storage system of ultracapacitor, battery.

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