KR101604792B1 - Nano composite, method for preparing the same, and supercapacitor - Google Patents

Abstract

A nanocomposite comprising a reduced graphene oxide (RGO) and a second functional group containing transition metal dichalcogenide (TMD) layer located on at least a portion of the surface of the graphene, A manufacturing method and a super capacitor including the same are provided.

Description

NANO COMPOSITE, METHOD FOR PREPARING THE SAME, AND SUPERCAPACITOR,

The present disclosure relates to nanocomposites, supercapacitors, and nanocomposites.

Supercapacitor is a capacitor having a very large capacitance. It is an energy storage device that uses a charge phenomenon by simple ion movement or surface chemical reaction between an electrode and an electrolyte interface unlike a battery using a chemical reaction, and an electric double layer capacitor (EDLC; Electric Double Layer Capacitor). As a result, it can be used as a secondary battery or a battery replacement due to its rapid charge / discharge, high charge / discharge efficiency and semi-permanent cycle life. This next-generation energy storage device, super capacitor, can store and use a large amount of electricity quickly and can be used. It can be used semi-permanently with a power more than 100 times higher than secondary battery and can be used in applications such as mobile phone, digital camera flash, It is important as a new and renewable energy storage device such as sunlight, wind power, and hydrogen fuel cell, which are environmentally clean alternative energy that does not emit carbon dioxide and replaces petroleum.

Recently, research on a composite material using an oxidation-reduction reaction of an electrode like a secondary battery has been going on in addition to the use of an electric double layer in energy storage in relation to a super capacitor. Particularly, it is possible to classify as a carbon-based, conductive polymer-based, and metal oxide-based materials as the electrode of the super capacitor. Among them, the carbon-based electrode material mainly stores energy in the electric double layer, And the metal oxide system using both the specific surface area and the oxidation-reduction reaction simultaneously has a disadvantage in that it exhibits a high storage capacity and is expensive. In addition, the conductive polymer using the oxidation-reduction reaction has a high storage capacity and has an advantage in terms of processability, but has a disadvantage that its lifetime characteristics are inferior. Therefore, in order to develop a supercapacitor electrode having high energy and high output characteristics, research is being conducted on a composite material using various advantages and disadvantages.

One embodiment of the present invention is to provide a nanocomposite having improved energy storage capability.

Another embodiment of the present invention is to provide a supercapacitor including the nanocomposite.

Another embodiment of the present invention is to provide a method for producing the nanocomposite.

One embodiment of the present invention is directed to a method of fabricating a semiconductor device comprising a first functional group containing transition metal dichalcogenide (TMD) layer located at least on a surface of a reduced graphene oxide (RGO) ≪ / RTI & gt ;

The first functional group and the second functional group may be covalently bonded to the graphene and the transition metal decalcogenide layer.

The first functional group may be a hydroxyl group, an epoxy, a carbonyl group, a carboxyl group, or a combination thereof. The second functional group may be selected from the group consisting of -S ^{2 -} (sulfide), - Se ^{2 -} (selenide), -Te ^{2 -} (telluride), and combinations thereof.

The transition metal decalcogenide layer may comprise at least one selected from MoS ₂ , WS ₂ , and combinations thereof.

The thickness of the graphene may be between 1 nm and 10 nm.

The thickness of the graphene may be between 1 nm and 5 nm.

The thickness of the transition metal decalcogenide layer may be between 1 nm and 10 nm.

The thickness of the transition metal decalcogenide layer may be between 1 nm and 5 nm.

The graphene and the transition metal decalcogenide layer may be contained in an amount of 5 to 20 wt% and 80 to 95 wt%, respectively, based on the total amount of the nanocomposite.

Another embodiment of the present invention is a method of manufacturing a semiconductor device, comprising: peeling a bulk transition metal dicalcogenide powder with a transition metal decalcogenide film;

Peeling the graphene oxide (GO);

Mixing the exfoliated transition metal decalcogenide film and the exfoliated graphene oxide and dispersing the mixture to obtain a dispersion;

A reducing step of adding a reducing agent to the dispersion to reduce it; And

And filtering the reduced dispersion to obtain a nanocomposite.

The step of peeling with the transition metal decalcogenide film comprises ultrasonically dispersing the bulk transition metal decalcogenide powder in N-methyl-2-pyrrolidone for 2 to 5 hours, dispersing the dispersion in water by at least 3 Centrifugation can be performed.

The centrifugation may be performed at a rate of 2000 to 5000 rpm.

The step of peeling the graphene oxide (GO) may be performed by ultrasonically dispersing the graphene oxide in distilled water for 30 minutes to 2 hours.

The step of obtaining the dispersion may be carried out by mixing the graphene oxide and the transition metal decalcogenide film in an amount of 5 to 20% by weight and 80 to 95% by weight, respectively, followed by dispersion treatment in distilled water for 2 to 5 hours .

The step of obtaining the dispersion may be carried out by dispersing treatment for 2 hours to 5 hours.

The reducing step may be carried out using a reducing agent selected from hydrazine, ascorbic acid, sodium ascorbate, sodium borohydride, and combinations thereof.

The reduction step may be carried out at a temperature of 70 ° C to 120 ° C for 10 hours to 15 hours.

The step of filtering the reduced dispersion may be performed by a vacuum filtering method.

Another embodiment of the present invention provides a supercapacitor including the above-described nanocomposite.

A nanocomposite having improved energy storage capability and a method of manufacturing the nanocomposite, and a supercapacitor including a nanocomposite can be realized.

1 is a graph showing XRD analysis results of a nanocomposite according to an embodiment of the present invention.
2 to 5 are graphs showing TEM analysis results of Example 1 and Comparative Examples 1 and 2.
6 is a graph showing the results of cyclic voltammetry measurement of Example 1 and Comparative Examples 1 and 2.

Hereinafter, embodiments of the present invention will be described in detail. However, it should be understood that the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

The nanocomposite according to one embodiment comprises a reduced graphene oxide (RGO) and a second functional group containing transition metal dichalcogenide (TMD) located at least a portion of the surface of the graphene. Layer.

The nanocomposite comprises a first functional group containing graphene.

Generally, the graphene (RGO) can be produced by treating graphene oxide (graphite oxide; hereinafter referred to as GO) with a chemical reduction method (hydrazine treatment) and / or a thermal reduction method. At this time, the reduced graphene is called RGO in particular.

Graphene oxide is a plate-shaped carbon material produced by acid treatment of graphite, which has a large amount of hydrophilic functional groups, carboxyl groups (-COOH), and hydroxyl groups (-OH). GO is prepared in the form of a hydrate form or a water-containing slurry in which the surface oxidation groups generated through an acid treatment process naturally form hydrogen bonds with H ₂ O. Typically, the solid content concentration of such a slurry is about 2 to 8% by weight, unless subjected to special treatment.

The GO improves the strength and has appropriate thermal conductivity when contained in a film or a structure, but treatment of the contained GO is a great obstacle to the manifestation of physical properties.

It has been proven that some of the oxidizing groups on the RGO surface can not be completely removed and the oxygen content by the surface oxidizing group is usually 5% or less of the carbon backbone, so that the graphene (RGO) Means that the oxygen content by the group is not more than 5% by weight based on the carbon backbone.

In addition, the nanocomposite may comprise a second functional group containing transition metal dicalcogenide located on at least a portion of the surface of the graphene.

A chalcogenide is a compound containing at least one Group 16 element, and a compound containing at least one Group 16 element other than oxygen is called a chalcogenide by being distinguished from an oxide.

The first functional group may be a hydroxyl group, an epoxy, a carbonyl group, a carboxyl group, or a combination thereof,

The second functional group is a -S ^{2 -} may be selected from (telluride), and combinations thereof ^{- (sulfide), -Se 2 -} (selenide), -Te 2.

The first functional group is an oxygen-containing group and may mediate the bonding with the second functional group on the surface of the graphene layer.

That is, ^{-S 2 - (sulfide), -Se} 2 - (selenide), -Te 2 - (telluride) is positioned opposite the pin and Yes, and a transition metal graphene radical scorching Need a single layer of each material are half It is combined by a Van der Waals force. Specifically, the surface negative charge of the graphene and transition metal decalcogenide is determined by the lone-pair electron of the oxygen-containing group of the graphene surface and the transition metal of the transition metal decalcogenide (Mo, W, etc.) or chalcogenide (S, Se, Te, etc.) atom.

The transition metal decalcogenide layer may comprise at least one selected from MoS ₂ , WS ₂ , and combinations thereof.

The thickness of the graphene may be 1 nm to 10 nm, specifically 1 nm to 5 nm.

The thickness of the transition metal dicalcogenide layer may be from 1 nm to 10 nm, specifically from 1 nm to 5 nm.

When the thickness of the graphene and the transition metal dicalcogenide is 5 nm or less, the specific surface area of the nanocomposite is increased, so that efficient charge accumulation of the electrolyte is possible.

The size of the transition metal decalcogenide layer may be relatively small compared to the size of the graphene. This facilitates the formation of a uniform single layer on the surface of the graphene, thereby increasing the specific surface area of the final nanocomposite.

The graphene and transition metal dicarcogenide layers may be contained in an amount of 5 to 20 wt% and 80 to 95 wt%, specifically 8 to 12 wt% and 88 to 92 wt%, respectively, based on the total amount of the nanocomposite.

When the content of the graphene and the transition metal decalcogenide layer is within the above range, homogeneous and effective surface bonding of graphene and transition metal decalcogenide can be induced, and thus, superconductivity using the final nanocomposite The capacity of the charge accumulation can be increased.

According to another embodiment of the present invention, there is provided a method of manufacturing a nanocomposite, comprising: peeling a bulk transition metal decalcogenide powder with a transition metal decalcogenide film; Peeling the graphene oxide (GO); Mixing the exfoliated transition metal decalcogenide film and the exfoliated graphene oxide and dispersing the mixture to obtain a dispersion; A reducing step of adding a reducing agent to the dispersion to reduce it; And filtering the reduced dispersion.

The step of peeling with the transition metal decalcogenide film comprises ultrasonically dispersing the bulk transition metal decalcogenide powder in N-methyl-2-pyrrolidone for 2 to 5 hours, dispersing the dispersion in water by at least 3 Centrifugation can be performed.

Examples of the dispersion medium of the transition metal decalcogenide include, but are not limited to, N-methyl-2-pyrrolidone.

The centrifugation may be carried out at a rotation speed of 2000 rpm to 5000 rpm, specifically 2500 rpm to 3200 rpm.

By centrifuging at the same speed as described above, it is possible to effectively purify and separate two-dimensional nanocomposites having a small thickness.

The step of peeling the graphene oxide (GO) may be performed by ultrasonically dispersing the graphene oxide in distilled water for 30 minutes to 2 hours.

The oxidized graphene may be graphene oxide, graphite oxide, or a combination thereof.

The step of obtaining the dispersion may be carried out by mixing the graphene oxide and the transition metal decalcogenide film in an amount of 5 to 20% by weight and 80 to 95% by weight, respectively, followed by dispersion treatment in distilled water for 2 to 5 hours .

If the mixing ratio is the same as above, uniform and effective surface bonding of the graphene and the transition metal decalcogenide can be induced.

The reduction step may be performed by a chemical reduction method, a thermal reduction method, or a combination thereof.

The chemical reduction method can be carried out at a temperature of 70 to 120 캜 for 10 to 15 hours using a reducing agent selected from hydrazine, ascorbic acid, sodium ascorbate, sodium borohydride and combinations thereof, and the like.

The step of filtering the reduced dispersion may be performed by a vacuum filtering method.

By passing through the final filtering step, a film made of a two-dimensional nanocomposite can be obtained, and this film shape can be applied to a form suitable for a supercapacitor electrode.

According to another embodiment, there is provided a supercapacitor including the aforementioned nanocomposite.

Hereinafter, specific examples of the present invention will be described. However, the embodiments described below are only intended to illustrate or explain the present invention, and thus the present invention should not be limited thereto.

In addition, contents not described here can be inferred sufficiently technically if they are skilled in the art, and a description thereof will be omitted.

Example  One

(Preparation of MoS ₂ film)

Bulk MoS ₂ powder (Aldrich-Sigma) was added to 1-methyl-2-pyrrolidone (NMP) solvent and ultrasonically dispersed for 3 hours or longer. The above-mentioned dispersion of MoS ₂ was centrifuged for 3 hours at 3000 rpm for about 1 hour, and then filtered to prepare an MoS ₂ film.

(Preparation of graphene-MoS ₂ nanocomposite)

The graphene oxide was added to distilled water and subjected to ultrasonic dispersion treatment for about 1 hour.

The graphene oxide dispersion and the MoS ₂ film were mixed at a weight ratio of about 1: 9, followed by ultrasonic dispersion treatment for about 3 hours.

Hydrazine was added to the dispersion and the mixture was subjected to a reduction reaction at a temperature of about 80 캜 for 12 hours.

The reduced dispersion was filtered to prepare a graphene-MoS ₂ nanocomposite.

Comparative Example  One ( bulk MoS ₂ Lt; / RTI &

Bulk MoS ₂ powder (Aldrich-Sigma) was added to 1-methyl-2-pyrrolidone (NMP) solvent and ultrasonically dispersed for 3 hours or longer to prepare a bulk MoS ₂ dispersion.

Comparative Example  2 (2D MoS ₂ Wow Grapina Hybrid Manufacturing )

Bulk MoS ₂ powder was added to NMP solvent and ultrasonically dispersed to prepare a transition metal chalcogenide dispersion.

The graphene oxide was added to distilled water and subjected to an ultrasonic dispersion treatment to prepare a graphene oxide dispersion.

The transition metal chalcogenide dispersion and the graphene oxide dispersion were simply mixed to prepare a hybrid solution.

Rating 1: Grapina - transition metal Dicalogenconide  Structure analysis

The X-ray diffraction analysis of Example 1 was performed using an XRD instrument (D8advance, Bruker, German), and the results are shown in FIG.

1 is a graph showing XRD analysis results of a nanocomposite according to an embodiment of the present invention.

Referring to FIG. 1, it can be confirmed that 2D MoS ₂ and graphene exist in the nanocomposite according to one embodiment of the present invention.

Evaluation 2: Grapina - transition metal Dicalogenconide  Shape analysis

Cross-sectional analyzes of Example 1 and Comparative Examples 1 and 2 were performed using a TEM (JEM-ARM200F, JEOL), and the results are shown in Figs. 2 to 5.

2 to 5 are graphs showing TEM analysis results of Example 1 and Comparative Examples 1 and 2.

2 to 5, it can be seen that the nanocomposite according to one embodiment of the present invention has a layered structure while maintaining the characteristics of each of graphene and MoS ₂ .

Rating 3: Grapina - transition metal Dicalogenconide  Electrochemical Characterization

The capacitance performance of the prepared graphene-transition metal dicalcogenide was evaluated by cyclic voltammetry (CV).

6 is a graph showing the results of cyclic voltammetry measurement of Example 1 and Comparative Examples 1 and 2.

Referring to FIG. 6, it can be seen that the redox current increases in the cyclic voltammetric characteristic of the graphene-transition metal dicalcogenide according to an embodiment of the present invention.

The non-storage capacity (Csp) was calculated by the following formula (1).

[Equation 1]

 Where v is the scan rate, V is the integration potential limit, I (V) is the voltammetric current, to be.

The calculation results are shown in Table 1 below.

The non-storage capacity (Csp) (F / g) Example 1 179 Comparative Example 1 4.6 Comparative Example 2 95

Referring to Table 1, it can be seen that the graphene-transition metal decalcogenide obtained at a scan rate of 100 mV / s exhibits a capacitance capacity of 179 F / g, as compared with Comparative Examples 1 and 2.

101: Transition metal chalcogenide layer in nanocomposite
102: Graphene layer in nanocomposites

Claims (16)

Reduced graphene oxide (RGO), and
And a second functional group containing transition metal dichalcogenide (TMD) layer disposed on at least a portion of the surface of the graphene,
The thickness of the transition metal decalcogenide layer is 1 nm to 5 nm,
Wherein the graphene and the transition metal decalcogenide layer are surface-bonded by a covalent bond between the first functional group and the second functional group,
The first functional group may be a hydroxyl group, an epoxy, a carbonyl group, a carboxyl group, or a combination thereof,
The second functional group is an ^{-S 2- (sulfide), -Se 2-} (selenide), -Te 2- (telluride), and the nanocomposite is selected from a combination of the two. delete delete The method according to claim 1,
Wherein the transition metal dicalcogenide layer comprises at least one selected from MoS ₂ , WS ₂ , and combinations thereof. The method according to claim 1,
Wherein the graphene has a thickness of 1 nm to 5 nm. delete The method according to claim 1,
Wherein the graphene and the transition metal dicarogenide layer are contained in an amount of 5 to 20 wt% and 80 to 95 wt%, respectively, based on the total amount of the nanocomposite. Peeling the bulk transition metal dicalcogenide powder with a transition metal decalcogenide film;
Peeling the graphene oxide (GO);
Mixing the exfoliated transition metal decalcogenide film and the exfoliated graphene oxide and dispersing the mixture to obtain a dispersion;
A reducing step of adding a reducing agent to the dispersion to reduce it; And
And filtering the reduced dispersion. ≪ RTI ID = 0.0 > 21. < / RTI > 9. The method of claim 8,
The step of peeling with the transition metal decalcogenide film comprises ultrasonic dispersion treatment of the bulk transition metal decalcogenide powder in N-methyl-2-pyrrolidone for 2 hours to 5 hours, Lt; RTI ID = 0.0 > 3-fold < / RTI > centrifugation. 10. The method of claim 9,
Wherein the centrifugation is performed at a rotation speed of 2000 rpm to 5000 rpm. 9. The method of claim 8,
Wherein the step of peeling the graphene oxide (GO) is carried out by subjecting the graphene oxide to ultrasonic dispersion treatment in distilled water for 30 minutes to 2 hours. 9. The method of claim 8,
The step of obtaining the dispersion is carried out by mixing the graphene oxide and the transition metal decalcogenide film in an amount of 5 to 20% by weight and 80 to 95% by weight, respectively, followed by dispersion treatment in distilled water for 2 to 5 hours A method for producing a nanocomposite. 9. The method of claim 8,
Wherein the reducing step is carried out using a reducing agent selected from hydrazine, ascorbic acid, sodium ascorbate, sodium borohydride, and combinations thereof. 9. The method of claim 8,
Wherein the reducing step is carried out at a temperature of 70 to 120 캜 for 10 to 15 hours. 9. The method of claim 8,
Wherein the step of filtering the reduced dispersion is performed by a vacuum filtering method. A super capacitor comprising the nanocomposite according to any one of claims 1, 4, 5, and 7.

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