KR102116844B1 - METHOD FOR CRYOGENIC KEEPING OF MXene - Google Patents

Abstract

The present invention relates to a low-temperature storage method of maxine, and more specifically, (a) preparing a maxine solution composed of a transition metal carbide and a transition metal carbonitride of a two-dimensional structure, (b) containing the prepared maxine solution in a container. Step, (c) comprises the step of rapidly cooling the maxine solution contained in the container so that the electrical properties are kept constant, and by rapidly cooling the maxine and storing it in a low temperature state, the electrical properties of the maxine can be kept constant.

Description

METHOD FOR CRYOGENIC KEEPING OF MXene

The present invention relates to a storage method of maxine, and more particularly, to a low temperature storage method of maxine capable of maintaining electrical properties constant through low temperature storage.

As one of the two-dimensional materials, the MAX phase (MAX phase, where M is a transition metal, A is a group 13 or 14 element, X is carbon and / or nitrogen) is a quasi-ceramic property MX, and a metal element A different from M is Combined crystalline, it has excellent physical properties such as electrical conductivity, oxidation resistance, and machinability. To date, more than 60 types of MAX phases are known to be synthesized.

The MAX phase is a two-dimensional material, but unlike graphite or metal dichalcogenide materials, the transition metal carbides are stacked with weak chemical bonds between element A and transition metal M between layers of each other. Therefore, it is difficult to transform into a two-dimensional structure using a general mechanical peeling method or a chemical peeling method.

However, in recent years, researchers led by Professor Michel W. Barsoum of Drexel University in 2011 used a hydrofluoric acid to selectively remove the aluminum layer from the MAX trader's three-dimensional titanium-aluminum carbide, resulting in a two-dimensional structure with completely different properties. Successful transformation. The researchers named the two-dimensional material obtained by exfoliating the MAX phase as "MXene". MXene has similar electrical conductivity and strength as graphene, and can be applied to various application technologies ranging from energy storage devices to biomedical applications and complexes.

However, when these maxines are dispersed in water and stored as a solution, they are easily oxidized by air and water and lose their original properties.

Therefore, in order to maintain the original characteristics, by storing the Ar atmosphere at a low temperature (5 ° C) when storing the maxinic solution, the characteristics could be maintained for a long time.

However, this storage method requires additional equipment such as vacuum equipment and Ar gas equipment in order to maintain the Ar atmosphere, thus increasing costs and unnecessary work.

Therefore, there is a need for a storage method that can more easily maintain the characteristics of the pulse fluid.

Published Patent Publication No. 10-2017-0036507 (2017.04.03.)

Technical problem to be achieved by the present invention is to provide a low-temperature storage method of maxine that can keep the electrical properties of the maxine constant by rapidly cooling the maxine and storing it in a low temperature state.

The technical problem to be achieved by the present invention is not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary knowledge in the technical field to which the present invention belongs from the following description. There will be.

In order to achieve the above technical problem, the low-temperature storage method of maxine according to the present invention comprises the steps of: (a) preparing a maxine solution composed of a transition metal carbide and a transition metal carbonitride of a two-dimensional structure, (b) the prepared maxine solution container Step (c) provides a step of rapidly cooling the maxine solution contained in the container so that electrical properties are kept constant.

In an embodiment of the present invention, the maxinic solution is Ti ₂ C, Ti ₃ C ₂ , V ₂ C, Nb ₂ C, (Ti _0.5 , Nb _0.5 ) ₂ CT _x , Ti ₃ CN, (V _0.5 , Cr _0.5 ) ₃ C ₂ , Ta ₄ C ₃ And Nb ₄ C ₃ .

In the embodiment of the present invention, in the step (b), the maxinic solution may be stored in a small amount of 5 mL or less.

In the embodiment of the present invention, the maxinic solution may be made of the formula of M _n + ₁ X _n .

In an embodiment of the present invention, M in the formula of M _n + ₁ X _n may be a front transition metal.

In an embodiment of the present invention, in the formula of M _n + ₁ X _n , X may also include at least one of carbon and nitrogen.

In an embodiment of the present invention, the rapid cooling of the maxine solution is made through a freezer and it is also possible to maintain a low temperature using helium or liquid nitrogen as a refrigerant.

In the embodiment of the present invention, it is also possible to store the maxinic solution in step (c) together with any one of inert gas, nitrogen gas, air or mixed gas.

In an embodiment of the present invention, the rapid cooling temperature in step (c) may be set to -80 ° C or less.

In an embodiment of the present invention, the sheet resistance value of the maxinic solution may be maintained at 10 Pa / sq or less through low temperature storage.

In an embodiment of the present invention, the rapid cooling temperature in step (c) may be set to -18 ° C to -80 ° C or less.

In an embodiment of the present invention, the sheet resistance value of the maxinic solution may be maintained at 100000 Pa / sq or less through low temperature storage.

In an embodiment of the present invention, a maxine device may be configured as an electrode material through a maxine solution stored through the low temperature storage method of the maxine.

In an embodiment of the present invention, the maxine solution stored through the low temperature storage method of the maxine may be manufactured in a film form through spin coating, drop casting, and vacuum filtration.

According to an embodiment of the present invention, the low-temperature storage method of maxine has an effect of rapidly maintaining the electrical properties of the maxine by rapidly cooling the maxine and storing it at a low temperature.

It should be understood that the effects of the present invention are not limited to the above-described effects, and include all effects that can be deduced from the configuration of the invention described in the detailed description or claims of the present invention.

1 is a flow chart of a method for storing cold at low temperature according to the present invention.
Figure 2 is a graph showing the concentration of the maxin solution according to the change in time and storage temperature and the conditions of the air or Ar atmosphere according to the present invention.
3 shows the sheet resistance value according to the change of temperature and time in air without an argon atmosphere according to the present invention.
FIG. 4 is an imaging diagram of the changed maxin solution when the maxin solution is stored in air according to temperature and time in FIG. 3 according to the present invention.
FIG. 5 is an imaging view of the changed maxine film when stored in the air according to temperature and time in FIG. 3 according to the present invention.
6 is an imaging and XRD graph of maxine immediately after synthesis according to the present invention and maxine stored in air and at low temperature for 1 month.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be implemented in various different forms, and thus is not limited to the embodiments described herein. In addition, in order to clearly describe the present invention in the drawings, parts irrelevant to the description are omitted, and like reference numerals are assigned to similar parts throughout the specification.

Throughout the specification, when a part is "connected (connected, contacted, coupled)" with another part, it is not only "directly connected" but also "indirectly connected" with another member in between. "It also includes the case where it is. Also, when a part “includes” a certain component, this means that other components may be further provided instead of excluding other components, unless otherwise stated.

The terminology used herein is only used to describe a specific embodiment, and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “include” or “have” are intended to indicate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, and that one or more other features are present. It should be understood that the existence or addition possibilities of fields or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance.

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

1 is a flow chart of a method for storing low temperature of maxine according to the present invention.

 The low-temperature storage method of maxine according to the present invention includes: (a) preparing a maxine solution composed of a transition metal carbide and a transition metal carbonitride of a two-dimensional structure (S110), (b) storing the prepared maxine solution in a container (S120) ), (c) It provides a step (S130) of containing the maxine solution in a container and rapidly cooling the electrical properties of the maxine solution to be kept constant.

In an embodiment of the present invention, the low temperature storage method of maxine may include preparing a maxine solution composed of a two-dimensional transition metal carbide and a transition metal carbonitride.

More specifically, Maxine is a two-dimensional layered structure, in which a layer composed of atoms is stacked to form a multilayer structure. Maxine, which is a two-dimensional multi-layer structure, has a light and low density, has excellent electrical conductivity, and can be easily separated from each other, and thus can be used as a radio wave absorber in various fields.

A maxine solution composed of a two-dimensional transition metal carbide and a transition metal carbonitride can be prepared for low temperature storage.

At this time, the maxin solution is Ti ₂ C, Ti ₃ C ₂ , V ₂ C, Nb ₂ C, (Ti _0.5 , Nb _0.5 ) ₂ CT _x , Ti ₃ CN, (V _0.5 , Cr _0.5 ) ₃ C ₂ , Ta ₄ C ₃ And Nb ₄ C ₃ .

In addition, the maxin solution may be composed of the formula of M _n + ₁ X _{n, in} the formula of M _n + ₁ X _n , M is an early transition metal, and X is at least one of carbon and nitrogen. And n may be an integer from 1 to 4.

In addition, the low-temperature storage method of maxine may include the step of placing the prepared maxine solution in a container.

In order to keep the prepared maxine solution at low temperature, it is distributed in a small amount in a container and stored by distributing it in 4 mL to 6 mL, and preferably in 5 mL, and storing in a container. When the maxine solution is distributed and stored in 7 mL or more, it is not uniformly cooled during rapid cooling, so the efficiency of rapid cooling may be reduced. When the maxin solution is distributed and stored in 3 mL or less, unnecessary work is increased due to small amount distribution. The efficiency of is reduced.

On the other hand, the low-temperature storage method of maxine may include the step of rapidly cooling the containment of the maxine solution in a container so that the electrical properties of the maxine solution are kept constant.

In order to keep the electrical properties of the maxinic solution constant, the maxinic solution can be rapidly cooled to a temperature of -80 ° C or lower.

Figure 2 is a graph showing the concentration of the maxine solution according to the conditions of the storage time (5 ℃, room temperature) and the air or Ar (argon) atmosphere during storage of the maxine solution.

Referring to FIG. 2, referring to the graph of FIG. 2 (a), the storage of the maxin solution in a low temperature and argon atmosphere and the storage of the maxin solution in room temperature and air are shown.

According to the graph (a), it can be seen that the concentration of the maxine solution is gradually maintained in the low temperature and argon atmosphere, but the concentration of the maxine solution gradually decreases when stored in room temperature and air.

In addition, when looking at the graph (b), if the concentration of the maxin solution is examined under the conditions of low temperature and argon atmosphere, room temperature and argon atmosphere, low temperature and air, room temperature and air, the storage temperature and argon atmosphere both change the concentration of maxine solution. It can be seen that it affects.

When the graphs of (a) and (b) are put together, a low temperature and argon atmosphere is required to keep the concentration of the maxin solution constant.

3 shows a sheet resistance value (electric conductivity) according to a change in temperature and time in air without an argon atmosphere.

Looking at Figure 3, as a result of measuring the sheet resistance value only by a change in temperature without argon atmosphere, when the maxin solution was stored for 22 days in low temperature (5 ℃) and air, it showed that the largest change, the resistance value was significantly increased You can. In addition, when stored for 22 days in a freezer (-18 ° C) and air, the change value is relatively small compared to a low temperature (5 ° C) and stored in air, and 28 in the freezer (-80 ° C or less) and air When stored for a day, the sheet resistance value remained almost constant.

Preferably, the sheet resistance value of the maxinic solution may be maintained at 10 Pa / sq or less through low temperature storage.

Therefore, if the maxine solution is stored in a freezer (-80 ° C or less) and air, the electrical properties of the maxine solution can be kept constant.

In addition, FIG. 4 is an imaging diagram of the changed maxine solution when stored in the air according to temperature and time in FIG. 3.

Referring to FIG. 4, the maxinic solution has a high temperature and is gradually oxidized to decrease in concentration over time, but can be discriminated through FIG. 4 when stored in a freezer (below -80 ° C). Therefore, if the maxine solution is stored in a freezer (-80 ° C or less) and air, the electrical properties of the maxine solution can be kept constant.

FIG. 5 is an imaging view of the changed maxine film when stored in air in accordance with temperature and time in place of the maxine film in FIG. 3 instead of the maxine solution.

Referring to FIG. 5, the maxine film has a high temperature and is oxidized and changes color over time, but can be discriminated through FIG. 4 when stored in a freezer (below -80 ° C). Therefore, if the maxine solution is stored in a freezer (-80 ° C or less) and air, the electrical properties of the maxine solution can be kept constant.

6 is an imaging and XRD graph of maxine immediately after synthesis and low temperature (5 ° C.) for 1 month and maxine stored in air.

Referring to FIG. 6, comparing the maxine immediately after synthesis (left) and the low temperature (5 ° C) for 1 month and the maxine stored in air (right), the low temperature for 1 month (5 ° C) and the maxine stored in air are immediately after synthesis. the color change compared to Maxine was deepening, the oxidation of Ti progress through XRD analysis, it can be confirmed that the Ti ₃ C ₂ is changed to TiO _2.

In general, the lower the temperature, the lower the diffusion coefficient and reactivity of air, and the lower the permeability of air in disordered ICE. Therefore, when the maxin solution is rapidly cooled in a freezer (-80 ° C or less), the disorder of ice becomes worse as compared to when stored in the freezer (-18 ° C), and as a result, the permeability through which air penetrates into the maxine decreases. . Therefore, if the maxine solution is stored in a freezer (-80 ° C or less) and air, the electrical properties of the maxine solution can be kept constant.

In addition, a maxine device may be configured as an electrode material through the maxine solution stored through the low temperature storage method of the maxine.

Meanwhile, the maxine solution according to the present invention can maintain the temperature of the freezer at -18 ° C to -80 ° C and maintain an appropriate level of electrical properties through rapid cooling.

More specifically, the maxin solution can maintain the electrical properties almost constant in the freezer (-80 ° C or less), but the temperature of the freezer is -18 ° C because it requires a lot of cost and additional equipment to maintain the temperature below -80 ° C. To -80 ° C to maintain an appropriate level of electrical properties. The appropriate level of electrical characteristics is to be maintained at 100 kPa / sq or less at 10 kPa / sq or more.

Therefore, depending on the manufacturing conditions, the maxin solution can be selectively stored at -80 ° C or lower or -18 ° C to -80 ° C when stored in a freezer to maintain an appropriate level of electrical characteristics, and reduce the cost for storage.

Meanwhile, when the maxinic solution is stored at a low temperature, it may be stored together with any one of inert gas, nitrogen gas, and air or a mixed gas.

More specifically, the maxine solution can be stored in any one of inert gas such as He, Ne, Ar, Kr, Xe, Rn, nitrogen gas or air, and the mixed gas or mixed gas in which the gas is mixed It is also possible to store the air in a mixed state.

Therefore, it is possible to block contact with oxygen by an inert gas or nitrogen gas, and it is possible to prevent the maxine solution from being combined with oxygen to change electrical properties.

In addition, the refrigerator for maintaining the maxin solution at a low temperature may be driven using helium or liquid nitrogen as a refrigerant.

In addition, the maxine solution stored through the low-temperature storage method of the maxine may be a maxine film manufactured in a film form through spin coating, drop cast, and vacuum filtration.

Therefore, by manufacturing the maxin film through various methods such as spin coating, drop casting and decompression filtration as described above, it is possible to effectively produce the maxin film according to manufacturing conditions or conditions.

The above description of the present invention is for illustration only, and those skilled in the art to which the present invention pertains can understand that the present invention can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the above-described embodiments are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all modifications or variations derived from the meaning and scope of the claims and their equivalent concepts should be interpreted to be included in the scope of the present invention.

Claims (14)

(a) preparing a maxine solution composed of a two-dimensional transition metal carbide and a transition metal carbonitride;
(b) placing the prepared maxin solution in a container;
(c) rapidly cooling the maxine solution contained in the container;
It includes,
In the step (c), the rapid cooling temperature is set to -80 ° C or less so that the sheet resistance value of the maxine measured by manufacturing the maxine solution with the maxine film is maintained at 10 MPa / sq or less in the air to maintain the electrical properties constant. Characterized by the low temperature storage method of Maxine. According to claim 1, wherein the maxin solution is Ti ₂ C, Ti ₃ C ₂ , V ₂ C, Nb ₂ C, (Ti _0.5 , Nb _0.5 ) ₂ CT _x , Ti ₃ CN, (V _0.5 , Cr _0.5 ) ₃ C ₂ , Ta ₄ C ₃ And Nb ₄ C ₃ Low temperature storage method of maxine. [3] The method of claim 2, wherein in the step (b), the maxine solution is distributed and stored in small portions of 5 mL or less to improve cooling efficiency during rapid cooling. The method of claim 3, wherein the maxine solution is formed of a chemical formula of M _n + ₁ X _n . The method of claim 4, wherein in the formula of M _n + ₁ X _n , M is a front transition metal. The method of claim 5, wherein in the formula of M _n + ₁ X _n , X comprises at least one of carbon and nitrogen. The method of claim 6, wherein rapid cooling of the maxine solution is performed through a freezer and low temperature is maintained using helium or liquid nitrogen as a refrigerant. The method of claim 7, wherein in the step (c), the maxine solution is stored together with any one of inert gas, nitrogen gas, and air, or a mixed gas. delete delete (a) preparing a maxine solution composed of a two-dimensional transition metal carbide and a transition metal carbonitride;
(b) placing the prepared maxin solution in a container;
(c) rapidly cooling the maxine solution contained in the container;
It includes,
In the step (c), the rapid cooling temperature is -18 ° C so that the sheet resistance value of the maxine measured by preparing the maxine solution as a maxine film is maintained at 10 kPa / sq or more and 100000 kPa / sq or less in the air to maintain electrical properties constant. Low temperature storage method of maxine, characterized in that set to -80 ℃.
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