KR102227753B1 - Porous carbon monoliths using engineering plastic and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a porous carbon monolith and a method for producing the same, and more specifically, a method for producing a porous carbon monolith having a hierarchical pore structure using engineering plastics, and a porous carbon monolith having a hierarchical pore structure prepared therefrom. About.

Description

Porous carbon monolith using engineering plastics and its manufacturing method {POROUS CARBON MONOLITHS USING ENGINEERING PLASTIC AND MANUFACTURING METHOD THEREOF}

The present invention relates to a porous carbon monolith and a method for producing the same, and more specifically, a method for producing a porous carbon monolith having a hierarchical pore structure using engineering plastics, and a porous carbon monolith having a hierarchical pore structure prepared therefrom. About.

The porous material is a material commonly used as a support for a catalyst or adsorbent, and is widely used in environmental fields such as absorbents and water treatment systems, as well as energy storage devices such as secondary batteries, depending on the size of pores and interconnectivity.

As the porous material, a porous carbon material such as graphene, carbon nanotubes, and carbon nanofibers not only has a high specific surface area, but also has excellent thermal and chemical stability, and is a catalyst for reasons such as conductivity and economy, and energy storage and separation of gases. It is widely used in various industrial fields such as storage of food.

The porous carbon material may be prepared by preparing a porous polymer material, stabilizing it and carbonizing it, and specifically, as the porous polymer material, conventional polyacrylonitrile (PAN), poly(vinyl alcohol) , PVA), pitch, phenolic resins, and cellulose derivatives are dissolved in an organic solvent, and then pores are formed by methods such as non-solvent phase separation (NIPS) or heat-induced phase separation (TIPS). , Pretreatment, heat stabilization, and carbonization to produce a porous carbon material.

However, in the conventional method of manufacturing a porous carbon material, not only damage to the internal pore structure due to heat occurs in the heat stabilization step, but also a large amount of manufacturing energy and time is required, making it difficult to mass-produce. Moreover, when manufacturing a porous carbon material using polymer materials such as PVA and pith, there is a disadvantage that additional pretreatment processes such as iodination and sulfonation are required to improve the carbonization yield.

In addition, studies are being attempted to manufacture a porous carbon material using conventionally widely used engineering plastics, but the porous engineering plastic carbon material to be manufactured can only be manufactured in the form of a membrane, so its shape and use. As is limited to the separation membrane, there is a problem that it is difficult to apply it to various fields.

Meanwhile, the porous carbon monolith may have different physical properties depending on the structure or size of pores formed therein, and pores are classified into micropores, mesopores, and macropores according to the size.

In addition, the internal pores of the porous carbon monolith affect ion transport resistance, conductivity, and diffusion distance, so it is an important variable when applied to energy materials such as supercapacitors that store electrical energy in the electric double layer that forms an interface between the electrode and the electrolyte. Becomes.

Accordingly, it is possible to develop a monolithic porous carbon material using engineering plastics, and a porous carbon monolith manufacturing technology that can induce maximization of performance and efficiency by having a specific pore structure in forming pores inside the monolith. Research and development is required. In particular, there is a need to develop a porous carbon monolith that can reduce cost and maximize productivity by reducing energy and time consumption during manufacturing.

Korean Patent Application Publication No. 10-2014-0055801

An object of the present invention is to provide a porous carbon monolith having a hierarchical pore structure manufactured using engineering plastics. More specifically, it is an object to provide a porous carbon monolith capable of mass production at low manufacturing cost as well as having excellent mechanical properties without harmful additives for improving physical properties by using engineering plastics when manufacturing the porous carbon monolith.

In addition, the present invention is capable of producing a monolithic porous carbon material by cooling, drying, and carbonizing the engineering plastics, thereby expanding the field of application of the engineering plastic carbon material limited to conventional separators.

In addition, it is an object of the present invention to provide a porous carbon monolith with easy control of the pore structure and maximization of productivity.

In addition, since the porous carbon monolith has a hierarchical structure, it is an object of the present invention to provide a porous carbon monolith having an improved specific surface area compared to a conventional porous carbon material and excellent electrochemical properties.

In order to solve the above problems, the present invention comprises the steps of preparing a polymer solution containing engineering plastics; Manufacturing a porous engineering plastic monolith for cooling and drying the polymer solution; And carbonizing the porous engineering plastic monolith. It provides a method for producing a porous carbon monolith having a hierarchical pore structure.

In the method of manufacturing a porous carbon monolith according to an embodiment of the present invention, the engineering plastic is polyester, polyamide, polyimide, polyetherimide, polysulfone ) And polyethersulfone (polyethersulfone) may be any one or a mixture of two or more selected from.

In the method of manufacturing a porous carbon monolith according to an embodiment of the present invention, the cooling may be performed at a temperature of -200 to 20° C. for 1 to 600 minutes.

In the method of manufacturing a porous carbon monolith according to an embodiment of the present invention, the drying may be performed for 1 to 100 hours by reducing the pressure to 1 to 500 mTorr at a temperature of -100 to 25°C.

In the method of manufacturing a porous carbon monolith according to an embodiment of the present invention, the carbonization may be performed at 500 to 3,000°C by heating at 1 to 20°C/min.

In the method of manufacturing a porous carbon monolith according to an embodiment of the present invention, the polymer solution may further include any one or more components selected from carbon nanotubes, graphite, graphene, and carbon nanofibers.

In the method of manufacturing a porous carbon monolith according to an embodiment of the present invention, the polymer solution may further contain a nitrogen-based compound.

In the method of manufacturing a porous carbon monolith according to an embodiment of the present invention, after the carbonization step of the porous engineering plastic monolith, an activation step may be further included.

In the method of manufacturing a porous carbon monolith according to an embodiment of the present invention, the activation may be performed at 200 to 1,000°C by raising the temperature at 1 to 20°C/min.

In the method of manufacturing a porous carbon monolith according to an embodiment of the present invention, the polymer solution may contain 0.1 to 80% by weight of engineering plastic.

In addition, the present invention provides a porous carbon monolith having a hierarchical pore structure manufactured by the above manufacturing method.

The porous carbon monolith having a hierarchical pore structure according to an embodiment of the present invention may have a BET surface area of 5 to 3,000 ㎡/g.

In the porous carbon monolith having a hierarchical pore structure according to an embodiment of the present invention, mesopores having an average diameter of 2 nm to 50 nm are formed inside macropores having an average diameter of more than 50 nm, and the average diameter inside the mesopores Micropores having a diameter of less than 2 nm may be formed to have a hierarchical pore structure that is interconnected.

In addition, the present invention provides an energy storage device including the porous carbon monolith having the above hierarchical pore structure as an electrode.

The energy storage device according to an embodiment of the present invention may be selected from a secondary cell, a fuel cell, a capacitor, a supercapacitor, and a solar cell.

In addition, the present invention comprises the steps of preparing a polymer solution containing engineering plastics; And cooling and drying the polymer solution.

In addition, the present invention provides a porous engineering plastic monolith having an average pore diameter of 1 nm to 1,000 μm, manufactured by the above manufacturing method.

According to the present invention, as a porous carbon monolith is manufactured by a simple process using engineering plastics, there is no need for a pretreatment process and an additional process of the thermal stabilization step that takes a lot of manufacturing time and energy to improve the conventional carbonization yield, and the manufacturing cost It has the advantage of being inexpensive and capable of mass production.

In addition, the present invention has a hierarchical structure in which the pore structure is easily controlled, the internal pores of the carbon monolith are interconnected, and thus has an improved specific surface area, excellent conductivity, thermal and mechanical properties, and further electrochemical properties, catalysts Or it has the effect of maximizing the adsorption performance efficiency.

In addition, the present invention is a secondary battery, a fuel cell, a capacitor, a supercapacitor, and an electrode material such as solar steam power generation to generate steam by absorbing sunlight, a water treatment system such as capacitive desalination, and a dye, radioactive material or heavy metal material adsorbent It can be used in various fields such as.

1 is a visual photograph of a porous engineering plastic monolith and a porous carbon monolith according to an aspect of the present invention.
2 is a graph showing a Raman spectrum and an X-ray diffraction (XRD) pattern analysis result of a porous carbon monolith according to an embodiment of the present invention.
3 is an SEM photograph of a porous engineering plastic monolith and a porous carbon monolith manufactured according to an aspect of the present invention.
4 is a graph showing nitrogen adsorption characteristics of a porous carbon monolith prepared according to an aspect of the present invention.
5 is a graph showing the pore size distribution of the porous engineering plastic monolith and the porous carbon monolith manufactured according to an aspect of the present invention.
6 is a graph showing the lithium secondary battery performance of a porous carbon monolith manufactured according to an aspect of the present invention.

Hereinafter, the present invention will be described in more detail through specific examples or examples including the accompanying drawings. However, the following specific examples or examples are only one reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

In addition, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. The terms used in the description in the present invention are merely for effectively describing specific embodiments and are not intended to limit the present invention.

One aspect of the present invention is a porous carbon having a hierarchical pore structure including a step of preparing a polymer solution containing engineering plastics, a step of producing a porous engineering plastic monolith for cooling and drying the polymer solution, and a step of carbonizing the porous engineering plastic monolith. It is to provide a method of manufacturing a monolith.

Hereinafter, a method of manufacturing a porous carbon monolith according to the present invention will be described in more detail step by step.

In one aspect of the present invention, the step of preparing the polymer solution is a step of dissolving the polymer before forming the porous engineering plastic monolith, and engineering plastics may be used as the polymer.

Specifically for the engineering plastics, for example, polyester, polyamide, polyimide, polyetherimide, polysulfone, polyethersulfone, polycarbonate (polycarbonate), polyoxymethylene, polybutylene terephthalate, polybenzimidazole, polyphenylene sulfide, polytetrafluoro ethylene, and polyether ketone It may be any one or a mixture of two or more selected from (polyetherkeone) and the like.

In one aspect of the present invention, the engineering plastics are preferably polyester, polyamide, polyimide, polyetherimide, polysulfone, and polyethersulfone. ) It may be to prepare a porous carbon monolith using any one or a mixture of two or more selected from. As the solution containing the engineering plastic is used, not only it is easy to manufacture the porous engineering plastic monolith through the cooling and drying steps of the present invention, but also the porous carbon monolith produced after the carbonization step has remarkably excellent thermal and mechanical properties. It has the effect of showing electrochemical stability.

If the engineering plastics are commonly used in this field, their weight average molecular weight is not significantly limited, but may be 10,000 g/mol to 500,000 g/mol, preferably 20,000 to 300,000 g/mol. Engineering plastics in the above range not only improve the desired thermal and mechanical properties, but also have an excellent effect as a carbon precursor in the subsequent carbonization step due to a high carbon content in the molecule.

In one aspect of the present invention, the polymer solution may contain an engineering plastic in an amount of 0.1 to 80% by weight, preferably 0.5 to 40% by weight, and more preferably 1 to 10% by weight, but is not limited thereto. When the above range is satisfied, not only is it effective in terms of manufacturing efficiency of the polymer monolith, but also it is preferable because it is effective to control the porosity and pore size of the polymer monolith.

As a method of preparing a polymer solution, for example, engineering plastics may be added to the above range to a solvent prepared at room temperature or heated, followed by stirring to dissolve.

As the solvent, as long as it is capable of dissolving engineering plastics, it may be used without much limitation. For example, an ether solvent, an alcohol solvent, an aromatic solvent, an alicyclic solvent, a heteroaromatic solvent, a heteroalicyclic solvent, an alkane solvent , It may be any one selected from a ketone solvent and a halogenated solvent, or a mixture thereof.

Preferably, as the solvent, any one or a mixture of two or more selected from dimethyl sulfoxide, N,N'-dimethylformamide, N,N'-dimethylacetamide, N-methylpyrrolidone and 1,4-dioxane It may be to use a solvent, but is not limited thereto. As the solvent is used, cooling of the polymer solution is easy in the subsequent step of forming the porous polymer monolith, and since the porosity and pore size of the polymer monolith are effectively controlled, the manufacturing efficiency can be further improved.

In one aspect of the present invention, the polymer solution may further include any one or two or more components selected from carbon nanotubes, graphite, graphene, and carbon nanofibers. Specifically, for example, it may be prepared by dissolving engineering plastics after dispersing the components in a solvent, but is not limited thereto. Porous carbon monoliths prepared including the above components further improve the excellent crystallinity of the carbon component and have better specific surface area and electrical conductivity, and thus exhibit the effect of improving ion storage properties and cycle stability when used as a supercapacitor.

In one aspect of the present invention, the polymer solution may further contain a nitrogen-based compound. The nitrogen-based compound is, for example, selected from ammonia, nitric acid, urea, amines, imines, nitriles, pyrroles, diazoles, triazoles, pyridines, diazines, triazines, and derivatives thereof. It may be any one or a mixture of two or more. More specifically, ammonia, nitric acid, urea, amine, diamine, triamine, polyamine, methylamine, ethylamine, dimethylamine, trimethylamine, aniline, pyrrole, pyrazole, imidazole, triazole, pyridine, pyridiazine , Pyrimidine, pyrazine, melamine, quinoline, phenanthroline, purine, pyrrolidine, ethyleneimine, acetonitrile, acrylonitrile and benzonitrile may be used, but are not limited thereto. By adding and stirring the nitrogen-based compound into the polymer solution, a nitrogen-doped porous carbon monolith can be prepared, and the nitrogen-doped porous carbon monolith has a rich electronic structure, so that electrical conductivity is remarkably improved, as well as super When used as a capacitor, it exhibits excellent effects in wettability with electrolyte and ion storage ability.

In one aspect of the present invention, the step of preparing the porous engineering plastic monolith is a step of cooling and drying the previously prepared polymer solution to form a porous structure, which is performed by cooling the polymer solution and then removing the solidified solvent crystals. I can. In this case, the solvent crystal refers to a solid state in which the solvent is frozen and hardened.

Although not limited to the above cooling method, for example, a porous structure may be formed by growing a solvent crystal in a polymer solution using liquid nitrogen gas.

In one aspect of the present invention, the cooling may be performed at a temperature of -200 to 20°C for 1 to 600 minutes, more preferably at -200 to -40°C for 5 to 60 minutes, but is not limited thereto. When cooling is performed in the above range, a regular porous structure is formed as the solvent crystals in the polymer solution grow, and the size of the formed pores is also very uniform. The porous structure formed at this time may be in the form of an interconnected network in which a honeycomb structure, a spider web structure, and a lattice structure are intertwined.

Then, the solvent crystals are removed through a drying process.

In one aspect of the present invention, the drying is performed by reducing pressure to 1 to 500 mTorr at a temperature of -100 to 25°C for 1 to 100 hours, more preferably at a temperature of -80 to -20°C to 100 to 500 mTorr to 24 to It may be carried out for 72 hours, but is not limited thereto. In the case of drying in the above range, the solvent crystals generated upon cooling are sublimated and are very effective in forming a hierarchical pore structure, and the formed pore structure is preferable because it exhibits high stability and specific surface area.

By converting the liquid polymer solution into a gaseous state through the above cooling and drying, the gas-liquid interface may be removed, and the stress of the engineering plastic monolith skeleton due to surface tension may be removed. Specifically, since the solvent is removed through sublimation, the porous structure of the engineering plastic monolith can be uniformly manufactured without shrinking compared to the conventional method, and the pores formed accordingly can exhibit an effect of having excellent stability.

As the drying process, an engineering plastic monolith having a porous structure may be manufactured by sublimating a solvent crystal through a freeze drying method or a supercritical drying method, but the method is not limited thereto.

The freeze-drying method may be performed using a known freeze-drying method, for example, by cooling to -40°C and reducing the pressure to increase the temperature step by step and maintaining the temperature for a certain period of time, but is not limited thereto.

The supercritical drying method may be carried out by setting a pressure vessel such as an autoclave to a critical pressure of 217.6 atm and a critical temperature of 374.2° C. or higher, which are critical conditions of water, and drying by gradually opening the pressure while the temperature is constant. The portion from which the solvent crystals are removed through the freeze drying method or the supercritical drying method may become pores of the porous engineering plastic monolith.

In the step of preparing a porous engineering plastic monolith by cooling and drying of the present invention, the pores formed from the polymer solution have an improved specific surface area and exhibit excellent stability, so that the thermal and mechanical properties of the porous carbon monolith produced through the subsequent carbonization step It has an effect that can significantly improve. In addition, it is possible to maximize the efficiency of electrochemical properties, catalyst or adsorption performance.

In one aspect of the present invention, the porous engineering plastic monolith may have an average pore diameter of 1 nm to 1,000 μm, preferably 2 to 100 nm. As the inside of the porous engineering plastic monolith includes a pore structure having an average diameter within the above range, it can be used for tissue engineering scaffolds in the bio-medical field, gas and liquid separation processes, molecular sieve adsorption, and the like.

In particular, in the case of conventional engineering plastics, which can only be manufactured in the form of a membrane, there is a limitation in the field of application, whereas the porous engineering plastic monolith manufactured through a combination of the polymer solution manufacturing step and the cooling and drying steps of the present invention is not only in the field of separators It has an advantage that can be applied to.

Subsequently, a porous carbon monolith is prepared by carbonizing the porous engineering plastic monolith. The carbonization step is carried out under an inert gas atmosphere, and the inert gas is not limited thereto, but any one selected from nitrogen, helium, argon, neon, and xenon may be mentioned.

In one aspect of the present invention, the carbonization is not limited as long as the temperature range at which the porous carbon monolith can be carbonized, but may be carried out at 500 to 3,000 °C, preferably 600 to 1,200 °C, more preferably 800 to 1,000 °C. It is not limited.

In addition, it is good to control the temperature increase rate in terms of structural stability of the porous carbon monolith to be produced. In this case, the temperature increase rate may be adjusted in the range of 1 to 20°C per minute, more preferably 5 to 10°C per minute, but is not limited thereto. Carbonization conditions in the above range are effective because the porous polymer monolith can be uniformly carbonized without deterioration in physical properties.

In one aspect of the present invention, after the carbonization step, the step of activating the porous carbon monolith may be further included, and the activation may be activating and heat-treating the porous carbon monolith by a physical or chemical method.

In one aspect of the present invention, the activation may be heat-treated at 500 to 800° C. by raising the temperature to 1 to 20° C./min and heating to 200 to 1,000° C., preferably 2 to 10° C./min, but is not limited thereto. .

As the activation method, for example, the porous carbon monolith may be heat-treated in the above range in a steam or carbon dioxide atmosphere, or the porous carbon monolith is immersed in a strong base aqueous solution and stirred for 1 to 6 hours, and then dried and in the above range. Heat treatment may be performed, but is not limited thereto.

As the activation step is further included after the carbonization step, the stability of the pore structure inside the porous carbon monolith to be produced is further improved, and at the same time, the specific surface area is remarkably increased. Accordingly, when the porous carbon monolith is used as a supercapacitor, it is effective to realize excellent electrochemical properties such as high capacity and high efficiency.

That is, through the combination of the polymer solution manufacturing step, the porous engineering plastic monolith manufacturing step, and the carbonization step of the present invention, it is possible to manufacture a carbon monolith having a hierarchical pore structure in a relatively simple process compared to the conventional porous carbon monolith manufacturing method. In addition, manufacturing costs are low and mass production is possible.

Furthermore, as the inside of the porous carbon monolith has a hierarchical pore structure, the specific surface area is remarkably improved and the structure stability is excellent. Due to this, thermal and mechanical properties are further improved, and excellent performance in electrochemical properties and catalyst or adsorption efficiency can be realized.

In addition, the porous carbon monolith according to the present invention includes a combination of micropores, mesopores, and macropores, wherein the micropores have an electrical double layer, mesopores have an ion transport path, and macropores have an ion buffering function that reduces the diffusion distance. By doing this, it is possible to realize a synergistic effect of the electrochemical properties.

In addition, the carbon material having the above structure is manufactured through a conventional difficult manufacturing process, has low productivity, has a problem that the structure is easily damaged during the process, and the yield is remarkably low, but the method of manufacturing a porous carbon monolith according to the present invention solves this problem. And has a high yield and excellent productivity.

The present invention provides a porous carbon monolith having a hierarchical pore structure manufactured by the above-described manufacturing method.

In one aspect of the present invention, the porous carbon monolith having a hierarchical pore structure may have a BET surface area of 5 to 3,000 ㎡/g, preferably 110 to 3,000 ㎡/g, more preferably 600 to 3,000 ㎡/g, It is not limited thereto.

In one aspect of the present invention, in the porous carbon monolith having a hierarchical structure, mesopores having an average diameter of 2 nm to 50 nm are formed inside the macropores having an average diameter of more than 50 nm, and the average diameter inside the mesopores is Micropores of less than 2 nm are formed to have a hierarchical pore structure that is interconnected. As pores having an average diameter as described above are formed in a hierarchical structure inside the porous carbon monolith, it can be used as a carbon electrode material such as secondary batteries and capacitors, and is easy to absorb/desorb, transport and diffuse ions. It has an advantage.

Porous carbon monoliths having a hierarchical pore structure representing the BET surface area and average diameter within the above range have excellent synergistic effects in the electrical double layer, ion transport pathway and ion buffering function, so that they are not only applied to energy devices, but also energy, environment, and electrical electronics. It has the advantage of high application value in various industrial fields such as.

The present invention provides an energy storage device comprising the porous carbon monolith having the above hierarchical pore structure as an electrode.

Specifically, the porous carbon monolith having a hierarchical pore structure according to the present invention not only has excellent mechanical properties, but also excellent electrochemical properties, as it includes engineering plastics, and thus secondary cells, fuel cells, capacitors, supercapacitors, and solar cells It can be used as an electrode of an energy storage device such as.

In one aspect of the present invention, a lithium secondary battery comprising a porous carbon monolith having a hierarchical structure manufactured by the above-described manufacturing method as an electrode has a maximum charging capacity of 200 mAh/g or more at 0.005 to 2 V, and a Coulomb efficiency. The Coulomb efficiency may be 90% or more, more preferably 95% or more, but is not limited thereto. A lithium secondary battery having a charging capacity and a Coulomb efficiency in the above range can implement excellent electrochemical properties, such as maintaining excellent ion storage properties and high energy density.

In addition, the porous carbon monolith having a hierarchical pore structure according to the present invention may be used as an electrode active material of a water treatment device including a capacitive desalination device, and may also be used as a catalyst or adsorbent for radioactive and heavy metal materials.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples. However, the following Examples and Comparative Examples are only one example for describing the present invention in more detail, and the present invention is not limited by the following Examples and Comparative Examples.

[Example 1]

Polyetherimide (ULTEM 1000, SABIC, 30,000-50,000 g/mol) was added in an amount of 3.8% by weight to 1,4-dioxane (Daejeonghwa Geum) at 70° C. and stirred for 300 minutes to prepare a polymer solution. Thereafter, the solution was cooled to -40°C for 10 minutes using liquid nitrogen, and then reduced to 5 mTorr at -90°C using a freeze dryer and maintained for 72 hours to form a dried porous engineering plastic monolith. It is shown in 1a.

Next, using a tubular furnace (Yulsan), the temperature was raised to 5°C/min in a nitrogen atmosphere and carbonization was performed at 1,000°C for 1 hour to prepare a porous carbon monolith, which is shown in FIG. 1B.

[Example 2]

It was carried out in the same manner as in Example 1, except that the carbonization temperature in Example 1 was changed to 800°C.

[Example 3]

Example 1 was carried out in the same manner as in Example 1, except that the polyimide (Matrimid 5218, Huntsman, 80,000 g/mol) was changed.

[Example 4]

After immersing the porous carbon monolith prepared in Example 1 in a 4 M aqueous KOH solution, the mixture was stirred at 25° C. for 2 hours. Subsequently, after complete drying in an oven at 80° C. for 12 hours, the temperature was raised to 5° C./min and maintained at 600° C. for 1 hour to obtain an activated porous carbon monolith.

[Example 5]

After immersing the porous carbon monolith prepared in Example 1 in a 4 M aqueous KOH solution, stirred at 25° C. for 2 hours, completely dried in an oven at 80° C. for 12 hours, and heated to 5° C./min at 700° C. Maintained for 1 hour to obtain an activated porous carbon monolith.

[Example 6]

After immersing the porous carbon monolith prepared in Example 1 in a 4 M aqueous KOH solution, stirred at 25° C. for 2 hours, completely dried in an oven at 80° C. for 12 hours, and heated to 5° C./min at 800° C. Maintained for 1 hour to obtain an activated porous carbon monolith.

[Comparative Example 1]

Polyetherimide (ULTEM 1000, SABIC, 30,000-50,000 g/mol) was added in an amount of 3.8% by weight to 1,4-dioxane (Daejeonghwa Geum) at 70° C. and stirred for 300 minutes to prepare a polymer solution. Subsequently, acetone was added to perform solidification by a non-solvent phase transfer method, and then immersed and stirred in distilled water at 25° C. and dried in an oven at 80° C. to form a porous engineering plastic monolith.

Next, using a tubular furnace (Yulsan), the temperature was raised to 5°C/min in a nitrogen atmosphere, and carbonization was performed at 1,000°C for 1 hour to prepare a porous carbon monolith.

(evaluation)

Figure 2 shows the Raman (LabRam ARAMIS, Horiba Jobin-Yvon, France) spectrum and XRD (X-ray diffraction, D8 Discover, Bruker, USA) pattern analysis results of the porous carbon monolith prepared from Example 1, which It was confirmed that the porous carbon prepared through was an amorphous carbon having a pseudographite structure.

In addition, FIG. 3A is an FE-SEM (Sirion, FEI, Netherlands) photograph of the porous engineering plastic monolith prepared from Example 1, and through this, the porous structure of the engineering plastic monolith according to crystal growth was confirmed. In addition, FIG. 3B is an FE-SEM photograph of the porous carbon monolith after carbonization, and it was confirmed that the pores of the carbon monolith have a hierarchical structure in which the pores of the carbon monolith are interconnected.

(1) adsorption properties

For the porous carbon monoliths prepared in Examples 1 to 6 and Comparative Example 1, respectively, after degassing from 423 K to 20 μTorr for 12 hours, nitrogen using a Nano POROSITY-XQ adsorption analyzer (Mirae SI) at 77 K. (N ₂ ) Adsorption-desorption test was performed. At this time, the volume of adsorbed nitrogen gas molecules and the surface area (S _BET ) were measured using the Brunauer-Emmett-Teller (BET) equation, and the total pore volume (V _TOTAL ) was measured from the amount of gas absorbed under 0.99 relative pressure. Average pore diameter was measured using the Barrett-Joyner-Halenda (BJH) method, and the results are shown in Table 1. Through this, in Examples 1 to 6, mesopores having an average diameter of 2 nm to 50 nm are formed inside the carbon monolith, and micropores having an average diameter of less than 2 nm are formed inside the mesopores to form a hierarchical pore structure that is interconnected. It was confirmed to have.

S _BET (㎡/g) V _TOTAL (cm 3 /g) Average pore diameter(nm) Example 1 181.3 41.62 3.426 Example 2 168.3 35.9 3.169 Example 3 150.7 33.5 3.264 Example 4 698.7 123.6 3.752 Example 5 750.9 156.7 3.334 Example 6 859.3 210.6 3.762 Comparative Example 1 108.7 18.9 3.520

_{4 shows adsorption isotherms analyzed by nitrogen (N 2} ) adsorption-desorption test for the porous carbon monolith prepared in Example 1, and it was confirmed that excellent adsorption performance was shown.

5 shows the results of measuring the pore size distribution (PSD) of the porous engineering plastic monolith and the porous carbon monolith prepared in Example 1 using the Barrett-Joyner-Halenda (B-J-H) method.

(2) electrochemical properties

Electrode and lithium ion secondary battery cell manufacturing

To test the performance of the lithium ion battery, a coin-type half-cell was constructed, and lithium metal was used as a reference electrode and a counter electrode. In addition, as an electrode connecting the film to be deposited, it was prepared as follows. As an active material, the porous carbon monoliths according to Example 1 and Comparative Example 1 were pulverized (325 mesh) with agate moltar, respectively. The active material and the binder PVDF (polyvinylidene fluoride) are mixed at a weight ratio of 9:1 and added to an NMP (n-methyl-2-pyrrolidone) solvent to make a slurry, and then coated on a copper foil to make a current collector electrode. I did. The electrode was used after drying at 110° C. for 2 hours before use, and was used as a 0.8 cm circular electrode. The electrolyte was 1M LiPF ₆ -EC/EMC (EC: ethylene carbonate, EMC: ethyl methyl carbonate, EC: EMC = 3: 7% by volume).

Electrochemical properties of the prepared electrode were evaluated using a charge-discharge curve. In the charge-discharge test, C-rate evaluation was conducted by adjusting the charge-discharge rate to 0.2, 0.5, 1, 2, 5, 10, 15 C within the voltage range of 0.005 to 2 V, and the results are shown in Table 2 and Fig. It is shown in 6.

division Initial charge-discharge curve C-rate evaluation Charging capacity
(mAh/g) Discharge capacity
(mAh/g) Coulomb efficiency
(%) Discharge capacity (1C)
(mAh/g) Discharge capacity (2C)
(mAh/g) Example 1 213.2 206 96.6 204.3 201.8 Comparative Example 1 120.7 111.3 82.2 115.8 113.6

As can be seen from Table 2, when using the porous carbon monolith of Example 1 as an active material for a secondary battery, it is possible to realize excellent lithium ion storage capacity and charge/discharge efficiency even though the energy and time in the process can be drastically reduced. Was able to confirm.

Through this, it was confirmed that the porous carbon monolith according to the present invention can implement excellent electrochemical properties by having a hierarchical pore structure and a high specific surface area.

Although a preferred embodiment of the present invention has been described above, it is clear that various changes, modifications, and equivalents can be used in the present invention, and the same can be applied by appropriately modifying the above embodiment. Therefore, the above description does not define the scope of the present invention determined by the limits of the following claims.

Claims (17)

Preparing a polymer solution by dissolving polyester, polyamide, polyimide, polyetherimide, polysulfone or polyethersulfone; Cooling the polymer solution, and then drying the porous engineering plastic monolith under reduced pressure at 1 to 500 mTorr at a temperature of -100 to 25°C; Carbonization of the porous engineering plastic monolith; And stirring the KOH aqueous solution for 1 hour to 6 hours, drying, and then heating at 1 to 20° C./min to activate at a temperature of 200 to 1,000° C.; of a porous carbon monolith having a hierarchical pore structure comprising Manufacturing method. delete The method of claim 1,
The cooling is performed for 1 to 600 minutes at a temperature of -200 to 20 ℃ method for producing a porous carbon monolith. delete The method of claim 1,
The carbonization is a method of producing a porous carbon monolith that is carried out at 500 to 3,000°C by raising the temperature to 1 to 20°C/min. The method of claim 1,
The polymer solution is a method for producing a porous carbon monolith further comprising any one or two or more components selected from carbon nanotubes, graphite, graphene, and carbon nanofibers. The method of claim 1,
The method for producing a porous carbon monolith wherein the polymer solution further comprises a nitrogen-based compound. delete The method of claim 1,
The activation is 1 to 20 ℃ / min by raising the temperature, 200 to 1,000 ℃ method for producing a porous carbon monolith to be carried out. The method of claim 1,
The polymer solution is a method of manufacturing a porous carbon monolith containing 0.1 to 80% by weight of engineering plastics. delete delete delete delete delete delete delete

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