KR20170103113A - Carbon composite, method of manufacturing the carbon composite, sodium-ion capacitor electrode including the carbon composite, and carbon-dioxide absorbent - Google Patents

Abstract

The present invention relates to a carbon composite, a manufacturing method thereof, a sodium ion capacitor electrode including the same, and a carbon dioxide adsorbent, wherein the carbon composite includes a carbonized biomass doped with a functional group including at least one selected among phosphorus (P), sulfur (S), and nitrogen (N). The carbon composite has a honeycomb structure therein and has a plurality of pores formed on the surface thereof. The carbon composite has electrochemical activity using a biomass which is a low-cost environmentally-friendly material, and the carbon composite can be easily manufactured through a simple process.

Description

TECHNICAL FIELD [0001] The present invention relates to a carbon composite material, an electrode for a sodium ion capacitor, and a carbon dioxide adsorbent containing the carbon composite material, a method for producing the carbon composite, an electrode for a sodium ion capacitor,

TECHNICAL FIELD The present invention relates to a carbon composite material, a method for producing the same, an electrode for a sodium ion capacitor including the carbon composite material, and a carbon dioxide adsorbent, and more particularly to a carbon composite material including a biomass, a method for producing the carbon composite material, Carbon dioxide adsorbent.

Biomass, a biological resource such as EFB (empty fruit bunch), which is a by-product of palm fruit, is eco-friendly and inexpensive. Therefore, researches for use as materials for biomass energy production and various technical fields are continuously carried out . Among them, carbonized biomass, which is carbonized to improve the chemical properties of biomass, is used as an alternative fuel for coal-fired power generation, an electrode active material, an adsorbent, and the like. Carbonated biomass is simply carbonized or activated to produce a carbon composite.

Recently, the demand for supercapacitors with high output is gradually increasing. In particular, sodium ion (Na-ion) capacitors are rich in sodium ions and have a potential similar to that of lithium ions, thereby replacing lithium-based electronic devices And is attracting attention as an energy storage device. In the case of using a metal oxide composite for the production of electrodes of a general capacitor, there is a limit to improve the characteristics of the capacitor because the lifetime of the capacitor is short and the movement of ions and electrons is slow. Therefore, it is necessary to develop electrode material with high energy storage capacity.

It is an object of the present invention to provide a biomass-based electrochemically activated carbon composite and a method of manufacturing the same.

Another object of the present invention is to provide an electrode for a sodium ion capacitor which can improve the energy storage capability of the carbon composite material.

Yet another object of the present invention is to provide a carbon dioxide adsorbent comprising the carbon composite material.

The carbon composite for one purpose of the present invention comprises carbonized biomass doped with a functional group containing at least one selected from phosphorus (P), sulfur (S) and nitrogen (N).

In one embodiment, the carbon composite material may be porous, having a honeycomb structure inside and having a plurality of pores on its surface.

In one embodiment, the carbonated biomass may be carbonized EFB (empty fruit bunch).

In one embodiment, the functional group may be hydrogen bonded to the carbonized biomass.

In one embodiment, the specific surface area of the carbon composite material may be 900 m ² / g to 1,500 m ² / g.

A method for producing a carbon composite material for an object of the present invention includes the steps of forming a doped carbonized biomass using biomass and at least one doping oxidant of phosphorus (P), sulfur (S), and nitrogen (N) And a step of vapor-activating the doped carbonization biomass.

In one embodiment, the step of forming the doped carbonized biomass may be performed by hydrothermal reaction by mixing the biomass and the doped oxidant with a solvent.

In one embodiment, the step of performing the steam activation treatment may be performed using at least one of carbon dioxide gas and steam in a nitrogen gas atmosphere.

In one embodiment, the doping oxidant is selected from the group consisting of phytic acid, phosphoryl chloride, methyl phosphonic acid, triphenylphosphine, thioglycolic acid, , At least one selected from 2-thiophenemethanol, benzyl disulfide, melamine, urea, and ammonia.

In one embodiment, in the step of performing the vapor activation treatment, the doping oxidizing agent may be a catalyst for vapor activation.

In one embodiment, a plurality of pores may be formed in the doped carbonization biomass in the steam activation process. At this time, the pores may be formed on the surface of the doped carbonized biomass having a honeycomb structure inside.

In one embodiment, the doped carbonization biomass comprises a functional group comprising at least one of phosphorus, sulfur and nitrogen, and the functional group may be hydrogen bonded to the carbonized biomass.

In one embodiment, the manufacturing method may further include lyophilizing the doped carbonization biomass before the step of performing the vapor activation treatment.

An electrode for a sodium ion capacitor for another purpose of the present invention consists of a porous carbon composite comprising a carbonaceous biomass doped with a functional group containing phosphorus (P).

In one embodiment, the carbon composite material may further include a functional group including at least one of nitrogen (N) and sulfur (S).

A carbon dioxide adsorbent for another purpose of the invention comprises a porous carbon composite comprising carbonized biomass doped with a functional group comprising nitrogen (N).

According to the carbon composite material of the present invention, the method for producing the carbon composite material, the electrode for a sodium ion capacitor and the carbon dioxide adsorbent containing the carbon composite material of the present invention, the carbon composite material has an electrochemical activity using biomass, And can be easily manufactured through a simple process. Carbon composite material, the carbonization step and the steam activation step are not merely individually combined, but the two steps interact with each other to produce a synergistic effect in improving the properties of the carbon composite material. The carbon composite material according to the present invention can be used as an electrode of a sodium ion capacitor to significantly improve the energy storage capability of a capacitor. At the same time, the carbon complex can be used alone as a carbon dioxide adsorbent because of its ability to adsorb carbon dioxide.

1 is a flowchart illustrating a method of manufacturing a carbon composite material according to an embodiment of the present invention.
2 is a view showing SEM photographs of phosphorus-doped carbonized EFB and Sample 1. FIG.
3 is a SEM photograph of sulfur-doped-carbonized EFB and sample 2. FIG.
4 shows SEM pictures of nitrogen doped-carbonized EFB and sample 3. Fig.
5 is a view showing SEM photographs of carbonized EFB and comparative sample 1. Fig.
6 is a graph showing the results of evaluating the carbon dioxide absorbing ability of each of Samples 1 to 3 and Comparative Sample 1 according to the present invention.
FIG. 7 is a graph showing the results of evaluation of energy storage characteristics of a capacitor to which Sample 1, Comparative Sample 1, phosphorous-doped EFB, and carbonized EFB, respectively, according to the present invention are applied.
8 is a graph showing graphs showing the results of specific surface area analysis (BET) of samples 1 to 3, respectively.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the term "comprises" or "having ", etc. is intended to specify that there is a feature, step, operation, element, part or combination thereof described in the specification, , &Quot; an ", " an ", " an "

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Carbon composites and their preparation

The carbon composite material according to the present invention comprises carbonized biomass doped with a functional group containing at least one selected from phosphorus (P), sulfur (S) and nitrogen (N).

The carbon composite itself is composed of carbonized biomass, and has a different electrochemical activity and carbon dioxide absorbing ability than carbonized biomass by being doped with a functional group containing phosphorus and / or nitrogen in the carbonated biomass. The functional group may be a functional group including any one of phosphorus, sulfur and nitrogen, and the carbon composite may include at least one of functional groups including any one of phosphorus, sulfur and nitrogen. For example, the carbon composite material may include a functional group containing phosphorus and a functional group containing nitrogen, that is, two kinds of functional groups. The functional group may be connected to the carbonized biomass by hydrogen bonding.

The carbonized biomass may be carbonized EFB (empty fruit bunch).

The inside of the carbon composite material may have a honeycomb structure. The carbon composite material may have a one-dimensional fiber bundle structure having a longitudinal direction. The cross-sectional surface cut in the direction in which the fibers are partially connected and cross the longitudinal direction may represent a honeycomb structure. At this time, a plurality of pores are formed on the surface of the carbon composite material, so that the carbon composite material may have porosity.

For example, when the carbon composite material is doped with a functional group having phosphorus, the carbon composite material may have electrochemical activity. When doped with a functional group having phosphorus, more pores are formed than when doped with a functional group having sulfur or nitrogen, so that when the carbon composite is used as an electrode for a sodium ion capacitor, the energy storage capacity can be maximized. Thus, the electrical characteristics of the high-output supercapacitor can be improved.

As another example, when the carbon composite material is doped with a functional group having nitrogen, the carbon composite material may have a capability of absorbing carbon dioxide. Since the carbon composite material contains basic nitrogen, it has acidic carbon dioxide absorption ability. In this case, the carbon composite material can be used as a carbon dioxide adsorbent.

As another example, the carbon composite may be doped with both a phosphorus-containing functional group and a nitrogen-containing functional group, and the carbon composite may have both electrochemical activity and carbon dioxide absorption ability.

The carbon composite material may have a specific surface area of 900 m ² / g to 1,500 m ² / g. For example, the specific surface area of the carbon composite material may be 1,000 m ² / g to 1,100 m ² / g. When the EFB is used as the biomass, the carbon composite material of the present invention has a specific surface area at least 90 times greater than that of the EFB having a specific surface area of 10 m ² / g at the maximum. When such a carbon composite material having a large specific surface area is used as an electrode for a high output supercapacitor, the energy storage ability can be remarkably increased and the carbon dioxide adsorbing ability can be remarkably improved.

Hereinafter, a method for producing a carbon composite material according to the present invention will be described in detail with reference to FIG.

1 is a flowchart illustrating a method of manufacturing a carbon composite material according to an embodiment of the present invention.

Referring to FIG. 1, the biomass and the doping oxidant are used to form a doped carbonization biomass (step S110).

The step of forming the doped carbonization biomass basically involves self assembly and hydrogen bonding between the biomass and the doping oxidizing agent. For this purpose, the step of forming the doped carbonized biomass may be performed by mixing the biomass and the doped oxidizing agent with a solvent such as water and hydrothermal reaction. For example, the hydrothermal reaction may be performed at a temperature of 180-220 < 0 > C for at least 10 hours.

The doping oxidant may be selected from the group consisting of phytic acid, phosphoryl chloride, methyl phosphonic acid, triphenylphosphine, thioglycolic acid, 2-thiophene, And may include at least one selected from the group consisting of 2-thiophenemethanol, benzyl disulfide, melamine, urea, and ammonia. Among them, phytic acid, phosphorous chloride, methylphosphonic acid and triphenylphosphine are doping oxidants for doping functional groups including phosphorus, and thioglycolic acid, 2-thiophenemethanol and benzyldisulfide contain sulfur Lt; / RTI > is a doping oxidant for doping functional groups. Also, melamine, urea, and ammonia are doping oxidants for doping functional groups containing nitrogen. The above doping oxidizing agents may be used alone or in combination of two or more. For example, phytic acid and melamine can be used as doping oxidants to dope the functional group containing phosphorus and the functional group containing nitrogen. The doping oxidizing agent may be used in a solution state in which a specific compound is dispersed in a solvent.

Since the hydrothermal reaction is a solvent such as water and the doping oxidant is also used in a solution state, self-assembly of the biomass in the hydrothermal reaction may occur. Simultaneously with the self-assembly of the biomass, functional groups are formed on the surface of the biomass and hydrogen bonds between the biomass and the functional groups are formed, so that the doped carbonized biomass doped with the functional groups can be formed.

After the hydrothermal reaction, an additional lyophilization process may be further performed. By the freeze-drying process, the surface tension of the solvent can be reduced.

Next, the doping carbonization biomass is subjected to a vapor activation treatment (step S120).

The steam activation treatment may be performed in a nitrogen gas atmosphere. The vapor activation process may be performed using at least one of carbon dioxide gas and steam in an inert gas atmosphere of nitrogen. Due to the steam activation process, a number of pores may be formed in the doped carbonization biomass to ultimately produce a porous carbon composite.

The doping oxidant added in the step of forming the doped carbonized biomass can be used as a catalyst for the activation reaction of the doped carbonized biomass in the vapor activation process. That is, the doping oxidant may be used as a catalyst in the vapor activation process to form a plurality of pores. As the doped oxidant is used as a catalyst, a carbon composite having a very large specific surface area having a specific surface area of 900 m ² / g to 1,500 m ² / g can be produced.

Hereinafter, the present invention will be described in detail with reference to specific production examples and characteristics evaluation of the prepared samples.

Preparation of Sample 1 (S'-P-EFB)

1 g of EFB (empty fruits bunch) purchased from Gendocs (company name, located in Malaysia) was mixed with 2 mL of phytic acid as a doping agent and hydrothermal reaction was carried out at 200 ° C for 12 hours. And lyophilized at -200 ° C. for 3 days to prepare carbonized EFB (M-EFB)

The phosphorus (P) -doped carbonized EFB (P-EFB) prepared by the hydrothermal reaction was activated at 800 ° C. in a quartz tube furnace while supplying nitrogen gas and water vapor to prepare Sample 1 (S'-P -EFB).

Preparation of Sample 2 (S'-S-EFB)

(S) -doped-carbonized EFB (S-EFB) was prepared (S-EFB) through substantially the same procedure as in the preparation of Sample 1, except that thioglycolic acid was used as the doping oxidant, 2 (S'-S-EFB).

Preparation of Sample 3 (S'-N-EFB)

(N) -doped carbonized EFB (N-EFB) was prepared and gas activated to form Sample 3 (S ') by substantially the same method as that of Sample 1 except that melamine was used as a doping oxidant. -N-EFB).

Preparation of Comparative Sample 1 (S'-M-EFB)

EFB (empty fruits bunch) was mixed with water, subjected to a hydrothermal reaction at 200 ° C for 12 hours, and then lyophilized at -200 ° C for 3 days to prepare carbonized EFB (M-EFB). This was activated in a quartz tube furnace at 800 DEG C while supplying nitrogen gas and water vapor to prepare Comparative Sample 1 (S'-M-EFB).

Structure verification

SEM images were obtained for each of the indium-carbonized EFB and Sample 1 produced during the manufacturing process of Sample 1. In addition, SEM images were obtained for each of the sulfur-doped-carbonized EFB, nitrogen-doped-carbonized EFB, and samples 2 and 3 produced in the manufacturing process of Sample 2 and Sample 3. The results are shown in Figs.

An SEM image was obtained for each of the carbonized EFB and Comparative Sample 1 produced in the manufacturing process of Comparative Sample 1. The results are shown in Fig.

FIG. 2 is a view showing SEM photographs of phosphorus-doped carbonized EFB and Sample 1, FIG. 3 is a SEM photograph of Sulfur-doped-carbonized EFB and Sample 2, SEM photographs.

(B) is a side view of the sample produced after the vapor activation treatment, and (c) is a side view of the sample prepared after the vapor activation treatment; Fig. 2 Surface image.

Referring to FIGS. 2 to 4 (a), it can be confirmed that the self-assembly of EFB by hydrothermal reaction has a fiber bundle structure of doped-carbonized EFB. At this time, it can be found that a small number of pores are formed on the surfaces of the fibers constituting the fiber bundle. On the other hand, as shown in Figs. 2 to 4 (b) and 4 (c), it can be confirmed that after the vapor activation treatment, a number of fine pores are formed on the surface remarkably in comparison with (a). Particularly, as shown in FIG. 2 (b), it can be seen that the cross-sectional structure of the doped-carbonized EFB has a honeycomb structure.

5 is a view showing SEM photographs of carbonized EFB and comparative sample 1. Fig.

5 (a) is a SEM image of EFB itself before carbonization, (b) is for carbonized EFB, and (c) and (d) are SEM images of Comparative Sample 1 produced after the vapor activation treatment .

Referring to FIG. 5 (a), it can be seen that the EFB itself before the carbonization has a smooth surface structure and the self-assembly of the EFB is performed with reference to the carbonized resultant (b). However, although the presence of the honeycomb structure and pores can be confirmed by referring to FIGS. 2C and 2D, unlike the SEM images of FIGS. 2 to 4B and 4C, As shown in Fig. That is, in the results of FIGS. 2 to 4, it can be seen that the doping oxidizing agent functions as a catalyst in forming the porous structure, and even when the doping oxidizing agent is used as in the present invention, the reduction of the effective surface area does not occur, You can see that you have it.

Characteristic evaluation-1

For each of Samples 1 to 3 and Comparative Sample 1 prepared above, the carbon dioxide absorption rate with respect to the pressure change was measured. The results are shown in Fig.

6 is a graph showing the results of evaluating the carbon dioxide absorbing ability of each of Samples 1 to 3 and Comparative Sample 1 according to the present invention.

S-P-EFB "is the sample 1," S'-S-EFB "is the amount of carbon dioxide absorbed (unit mmol / g) Sample 2, "S'-N-EFB" represents Sample 3, and "S'- M-EFB"

Referring to FIG. 6, it can be seen that the absorbed amount of carbon dioxide increases with increasing pressure in all of the samples 1 to 3 and the comparative sample 1, but in the case of the samples 1 and 2 and the comparative sample 1, And it is saturated. On the other hand, in the case of Sample 3 containing nitrogen, unlike Sample 1 or 2 or Comparative Sample 1, the carbon dioxide uptake tends to increase continuously as the pressure increases.

That is, in the case of Sample 3 containing nitrogen, not only the surface area was increased due to the formation of pores, but also because the pores showed basicity by nitrogen, it was possible to adsorb more acidic carbon dioxide .

Characteristic evaluation -2

A three-electrode system was constructed using Sample 1, Comparative Sample 1, phosphorous-doped EFB and carbonized EFB, respectively, and energy storage characteristics were evaluated using NaClO ₄ in EC / DMC (ethylene carbonate / dimethyl carbonate) . The results are shown in Fig.

FIG. 7 is a graph showing the results of evaluation of energy storage characteristics of a capacitor to which Sample 1, Comparative Sample 1, phosphorous-doped EFB, and carbonized EFB, respectively, according to the present invention are applied.

7, " M-EFB "represents carbonized EFB," P-EFB "represents doped- "Represents Sample 1. "

Referring to FIG. 7, it can be seen that the comparative sample 1 or sample 1 having pores has a remarkable energy storage capacity as compared with the non-steam activated carbonized EFB or the phosphorous-doped carbonized EFB. It can be seen that the comparative sample 1 and the sample 1 have a relatively larger energy storage capacity than the comparative sample 1 in the case of the sample 1 doped with the functional group containing phosphorus.

That is, in the case of the sample 1 doped with the phosphorus-containing functional group, not only the surface area is widened due to the formation of the pores, but also the presence of phosphorus makes the sodium ion of the electrolyte easy to be adsorbed by physical bonding, Ion capacitors and the storage capacity of the capacitors is greatly increased.

Characteristic evaluation -3

8 is a graph showing graphs showing the results of specific surface area analysis (BET) of samples 1 to 3, respectively.

In FIG. 8, (a) is a graph of a specific surface area analysis result of Sample 1, (b) is a graph of a specific surface area analysis result of Sample 2, and (c) is a graph of a specific surface area analysis result of Sample 3.

Referring to FIG. 8, it can be seen that the specific surface area of each of Samples 1 to 3 is 1109.5 m ² / g, 1009.9 m ² / g, and 1050.9 m ² / g. That is, considering that the specific surface area of EFB is 10 m ² / g level, it can be confirmed that the specific surface area is remarkably increased. It can be seen that the increase of the specific surface area results from the generation of pores by the vapor activation treatment and the result that the doping oxidant in the vapor activation treatment process further improves the pore generation amount.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims. It can be understood that it is possible.

Claims (17)

And carbonized biomass doped with a functional group containing at least one selected from phosphorus (P), sulfur (S), and nitrogen (N).
The method according to claim 1,
Characterized in that it has a honeycomb structure inside and a porous surface on which a plurality of pores are formed.
Carbon complex.
The method according to claim 1,
Wherein the carbonized biomass is carbonized EFB (empty fruit bunch).
The method according to claim 1,
Wherein the functional group is hydrogen bonded to the carbonized biomass.
Carbon complex.
Forming biomass and a doped carbonization biomass using a doping oxidant of at least one of phosphorus (P), sulfur (S), and nitrogen (N); And
And performing a vapor activation treatment on the doped carbonization biomass.
Carbon composite.
6. The method of claim 5,
The step of forming the doped carbonization biomass
Characterized in that it is carried out by hydrothermal reaction by mixing the biomass and the doping oxidant with a solvent.
Carbon composite.
6. The method of claim 5,
The step of activating the steam
Characterized in that at least one of carbon dioxide gas and water vapor is used in a nitrogen gas atmosphere,
Carbon composite.
6. The method of claim 5,
The doping oxidant
Phytic acid, phosphoryl chloride, methyl phosphonic acid, triphenylphosphine, thioglycolic acid, 2-thiophenemethanol (2- characterized in that it comprises at least one selected from thiophenemethanol, benzyl disulfide, melamine, urea and ammonia.
Carbon composite.
6. The method of claim 5,
In the steam activation treatment step
Characterized in that the doping oxidant is a catalyst for vapor activation.
Carbon composite.
6. The method of claim 5,
In the steam activation treatment step
Characterized in that a plurality of pores are formed in the doped carbonization biomass.
Carbon composite.
11. The method of claim 10,
The pores
Characterized in that the inside is formed on the surface of a doped carbonized biomass having a honeycomb structure.
Carbon composite.
6. The method of claim 5,
Wherein the doped carbonization biomass comprises a functional group comprising at least one of phosphorus, sulfur and nitrogen,
Characterized in that the functional group is hydrogen bonded to the carbonized biomass.
Carbon composite.
6. The method of claim 5,
Before the steam activation treatment step,
Further comprising the step of lyophilizing the doped carbonized biomass.
Carbon composite.
A porous carbon composite material comprising a carbonaceous biomass doped with a functional group containing phosphorus (P)
Electrodes for sodium ion capacitors.
15. The method of claim 14,
Characterized in that the carbon composite further comprises a functional group containing at least one of nitrogen (N) and sulfur (S).
Electrodes for sodium ion capacitors.
A carbon composite material comprising a porous carbon composite material comprising carbonized biomass doped with a functional group containing nitrogen (N)
Carbon dioxide adsorbent.
The method according to claim 1,
And a specific surface area of 900 m ² / g to 1,500 m ² / g.
Carbon complex.

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