Method and apparatus for producing intercalation compound

Abstract

To provide a method for producing a graphite intercalation compound, which does not require mechanical operation, does not require post-treatment such as removal of a catalyst depending on the kind of an alkali metal, is simple and high-speed, and enables mass synthesis.SOLUTION: According to one aspect of the present invention, there is provided a method of manufacturing an intercalation compound comprising a base material and an insertion material, the method comprising the steps of: introducing the base material and the insertion material into a container in the presence of an inert gas; heating the container to a temperature sufficient for the insertion material to become liquid in the presence of the inert gas; forming the intercalation compound by direct contact and reaction between the base material and the liquid; and continuing to heat the container for a time sufficient to complete the reaction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method and an apparatus for producing an intercalation compound, and more particularly to a method and an apparatus for easily synthesizing a graphite intercalation compound of an alkali metal or alkaline earth metal. [Background technology]

[0002] Graphite intercalation compounds (GICs), obtained by intercalating graphite with alkali metals or alkaline earth metals, are noteworthy materials with promising properties that could be used in the development of various devices and materials. They are expected to be used in a variety of fields, including as anode materials for lithium secondary batteries, hydrogen storage materials, electrochemical devices with power storage capabilities, and as intermediate materials for graphene production.

[0003] There are several methods for intercalating an alkali metal or alkaline earth metal into graphite to form a graphite intercalation compound (Non-Patent Document 1).

[0004] First, there is the gas-phase method in which alkali metal vapor, which has been gasified at high temperatures, is brought into contact with graphite (Non-Patent Document 2). In this method, an alkali metal or alkaline earth metal is heated and vaporized under reduced pressure, and the gaseous metal is then reacted with graphite to synthesize graphite. This synthesis method is widely known as a method for synthesizing GICs from alkali metals or alkaline earth metals, and is described, for example, in Patent Document 1 as a method for synthesizing alkali metal GICs as intermediate materials for producing graphene.

[0005] The next well-known method is the molten salt method, in which graphite is synthesized by immersing it in alkali metal salts molten at high temperatures (the melting point of lithium chloride is 605°C, and the melting point of potassium chloride is 770°C) for a long period of time (Non-Patent Document 3).

[0006] In recent years, a method known as the "sodium catalyst method" has been reported (Non-Patent Document 4). This method involves mixing an alkali metal or alkaline earth metal, such as lithium metal, with sodium metal at room temperature in a glove box or similar device, adding graphite and mixing for at least 10 minutes to synthesize an alkali metal GIC or alkaline earth metal GIC. This method has attracted attention because it allows GIC to be synthesized at room temperature, eliminating the need for an electric furnace or other equipment, and allowing for the easy synthesis of large quantities of GIC. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] WO2014 / 136757 [Non-patent literature]

[0008] [Non-Patent Document 1] T. Ohzuku, et.al., J. Electrochem. SOC., 140, 2490 (1993). [Non-patent document 2] R.Nishitani,et.al.,Phys.Rev.B,27,6572(1983). [Non-patent document 3] M.Inagaki,et.al.,Synth.Met.,20,1(1987). [Non-patent document 4] A.Iyo,et.al.,Adv.Mater.,35,2209964(2023). [Non-Patent Document 5] AIST News, "Development of a simple and rapid synthesis method for graphite intercalation compounds (GIC)" (2023). Summary of the Invention [Problem to be solved by the invention]

[0009] Three techniques were introduced above as typical methods for synthesizing alkali metal or alkaline earth metal GICs. However, each of these synthesis methods has its own issues, and no method has yet been established that allows for the simple, rapid mass production of alkali metal or alkaline earth metal GICs.

[0010] For example, in the gas-phase method, the synthesis rate of GIC depends on the vapor pressure of the alkali metal. However, even under reduced pressure, the vapor pressure of these metals is low, so large-scale synthesis takes an extremely long time, about a week. Furthermore, the metal must be heated to at least 300°C until it becomes a gas. Alkaline earth metals have extremely high melting points, making them unsuitable for gas-phase synthesis. Furthermore, because the metal surface is oxidized, an additional distillation process under vacuum is required, making the entire synthesis process complicated and unsuitable for industrial mass production.

[0011] Next is the molten salt method. In this method, metal salts are melted, so the synthesis process requires a much higher temperature than the gas-phase method; for example, the melting point is 605°C for lithium chloride and 770°C for potassium chloride, and it also takes a long time.

[0012] Even the sodium catalyst method, which emerged as a simple synthesis method, involves mechanical work such as mixing and grinding the materials with a pestle-like object at a certain force during the synthesis process. Therefore, when attempting to synthesize large quantities, it is unavoidable to increase the size of the synthesis equipment, and there are issues such as the need for post-processing because the catalyst components need to be removed.

[0013] In the past, research and development of alkali metal or alkaline earth metal GICs has been conducted as hydrogen storage materials and electrochemical devices with electricity storage capabilities. Recently, research and development has also been conducted to use GICs as intermediate materials for graphene production. However, the lack of a method for inexpensively mass-producing GICs has been a bottleneck in development, and the results of this research and development have not led to practical application.

[0014] Although GICs using alkali metals or alkaline earth metals are expected to be used in a wide range of industrial fields, there is currently no method for easily and quickly synthesizing them in large quantities, and therefore a method for producing them has been desperately needed.

[0015] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a manufacturing method and manufacturing apparatus that can easily synthesize a graphite intercalation compound of an alkali metal or alkaline earth metal. [Means for solving the problem]

[0016] (1) The method for producing an intercalation compound according to the present invention is a method for producing an intercalation compound consisting of a base material and an intercalation substance, and is characterized by comprising an introduction step of introducing the base material and the intercalation substance into a container in the presence of an inert gas; a heating step of heating the container to a temperature sufficient to liquefy the intercalation substance in the presence of the inert gas; a formation step of forming the intercalation compound by directly contacting the base material with the liquid and causing a reaction; and a heating continuation step of continuing to heat the container for a time sufficient to complete the reaction.

[0017] The method for producing an intercalation compound according to the present invention may further include a depressurizing step of depressurizing the inside of the container between the introducing step and the heating step.

[0018] In the method for producing an intercalation compound according to the present invention, the base material is preferably selected from layered carbon materials such as graphite, expanded graphite, and graphite-like materials.

[0019] In the method for producing an intercalation compound according to the present invention, when the base material is a fine powder, it is better to use it by flaking it.

[0020] In the method for producing an intercalation compound according to the present invention, the intercalation material is one or more metals selected from alkali metals such as lithium, sodium, potassium, rubidium, and cesium, and alkaline earth metals such as magnesium, calcium, strontium, and barium.

[0021] In the method for producing an intercalation compound according to the present invention, the ratio of the base material to the intercalation substance in the introduction step is in the range of 100 to 250% of the stoichiometric molar ratio at which an intercalation compound called Stage 1 is formed after completion of the reaction in the heating continuation step, where the ratio is 100 to 200%, preferably 100 to 150%.

[0022] In the method for producing an intercalation compound according to the present invention, the atmosphere in the introducing step is preferably filled with the inert gas so that oxygen, moisture, etc. that react with the intercalation substance do not contain more than 0.1%.

[0023] In the method for producing an intercalation compound according to the present invention, the pressure reduction step is preferably carried out so that the pressure reduction state does not contain more than 0.1% of oxygen or moisture that reacts with the intercalation substance.

[0024] In the method for producing an intercalation compound according to the present invention, the heating step is preferably performed to a temperature at which the intercalation substance becomes liquid, and in the range of 60°C to 500°C.

[0025] In the method for producing an intercalation compound according to the present invention, when the intercalation substance does not become liquid in the temperature range of 60°C to 500°C, a metal having a melting point of 100°C or less is used as an additive metal substance for lowering the melting point, and the additive metal substance and the intercalation substance are mixed in a molar ratio of 0.5 to 2 when the additive metal substance is 1, thereby lowering the melting point to a temperature range of 60°C to 500°C, thereby enabling low-temperature synthesis.

[0026] (2) The apparatus for manufacturing an intercalation compound according to the present invention is an apparatus for manufacturing an intercalation compound consisting of a base material and an intercalation substance, and is characterized by having a container into which the base material and the intercalation substance are introduced in the presence of an inert gas, a heating mechanism for heating the container to a temperature sufficient to turn the intercalation substance into a liquid in the presence of the inert gas, a direct contact mechanism for forming the intercalation compound by directly contacting and reacting the base material with the liquid, and a heating continuation mechanism for continuing to heat the container for a time sufficient to complete the reaction.

[0027] In the intercalation compound manufacturing apparatus according to the present invention, the container may include a pressure reducing mechanism that reduces the pressure after the base material and the intercalation substance are introduced.

[0028] In the intercalation compound manufacturing apparatus according to the present invention, the heating mechanism preferably heats the intercalation substance to a temperature of 60° C. to 500° C., which is higher than the temperature at which the intercalation substance becomes the liquid.

[0029] In the apparatus for producing an intercalation compound according to the present invention, the direct contact mechanism preferably continuously mixes and contacts the base material and the intercalant liquid obtained by heating by stirring, shaking, etc. to improve the reaction rate, and preferably includes a stirring mechanism. This stirring function allows the liquid to come into contact with the base material that has not yet been synthesized, making it possible to produce a homogeneous GIC.

[0030] In the intercalation compound manufacturing apparatus according to the present invention, the heating continuation mechanism needs to have the function of continuing to heat the container for a period of time sufficient to complete the reaction, and it is preferable to continue heating for one hour to one day as the period of time sufficient to complete the reaction. [Effects of the Invention]

[0031] According to the present invention, it is possible to provide a manufacturing method and a manufacturing apparatus that can easily synthesize a graphite intercalation compound of an alkali metal or alkaline earth metal.

[0032] In particular, there is no need to synthesize under vacuum conditions at a high temperature of about 400°C for about a week as in the gas phase method, nor is there any need to synthesize at a high temperature of 500°C or higher for about a week as in the molten salt method, and there is no need to apply force to crush and mix the base material and the intercalation substance as in the Na catalyst method.

[0033] The present invention provides a method for mass-synthesizing alkali metal or alkaline earth metal GICs in an inert gas atmosphere under reduced or atmospheric pressure at relatively low temperatures above the melting points of these metals, in a matter of a few hours to a day. This method is therefore of great benefit to industrial fields requiring large quantities of GICs. [Brief explanation of the drawings]

[0034] [Figure 1] 1 is a structural diagram showing an example of an apparatus for producing an intercalation compound according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] Embodiments of a method and apparatus for producing an intercalation compound according to the present invention will be described. The present invention is not limited to the following embodiments and examples, and can be modified in various ways as long as it includes the gist of the present invention. Below, modes for realizing the present invention will be described in the order of materials, apparatus, and process. Note that "alkali metal GIC" refers to a graphite intercalation compound with an alkali metal as an intercalation material, and "alkaline earth metal GIC" refers to a graphite intercalation compound with an alkaline earth metal as an intercalation material.

[0036] (material) First, regarding materials, synthesizing alkali metal or alkaline earth metal GICs requires two components: a host material and an intercalator.

[0037] The matrix is ​​selected from layered carbon materials such as graphite, expanded graphite, and graphite-like materials. Expanded graphite is preferred because it is easily available in flake form suitable for manufacturing. Expanded graphite is a highly expanded form of graphite that has nitrate ions intercalated between the graphite layers.

[0038] The intercalant may be one or more metals selected from the alkali metals lithium, sodium, potassium, rubidium, and cesium, and the alkaline earth metals magnesium, calcium, strontium, and barium.

[0039] (manufacturing equipment) Next, we will explain the equipment. The manufacturing equipment requires four elements: a container, a heating mechanism, a direct contact mechanism, and a heating continuation mechanism.

[0040] This device is predicated on being equipped with the base material and a container into which the intercalant is introduced. Since the intercalant, an alkali metal or alkaline earth metal, is prone to react with water, it is necessary to remove the moisture from the container. To achieve this, mechanisms are required, such as filling the container with an inert gas such as argon or nitrogen, or a decompression mechanism to remove the moisture by reducing the pressure. At the laboratory level, glass tubes or quartz tubes are commonly used for the container, but for large-scale synthesis, metals or highly heat-resistant resins can also be used.

[0041] Next, a heating mechanism is required to liquefy the intercalation substance. While some alkali metals have low melting points, alkaline earth metals have high melting points. When synthesizing GICs of such high-melting-point metals, it is possible to lower the heating temperature by mixing a low-melting-point metal, such as sodium, and using the alloy to lower the melting point through freezing-point depression. Therefore, it is desirable to be able to heat the material to a temperature of approximately 60°C to 500°C. A gas burner or electric furnace can be used as a heating mechanism, but a hot bath can also be used, especially when heating alkali metals with low melting points.

[0042] The third mechanism is a direct contact mechanism. The key to this manufacturing method is to bring the intercalation substance, which has been liquefied by heating, into contact with the base material, and intercalate the intercalation substance between the layers of the base material through capillary action. Therefore, a stirring mechanism is provided as a direct contact mechanism to improve the reaction rate during synthesis and to progress the synthesis in a short period of time. This stirring mechanism can mix and stir the base material and the intercalation substance, or it can stir by shaking the entire container.

[0043] The final component of the manufacturing equipment is a continuous heating function. In order to complete the reaction between the base material and the intercalation substance, the intercalation substance must be kept in a liquid state throughout the reaction process. Therefore, a heating or heat retention mechanism is required to keep the intercalation substance in a liquid state for at least one hour, and up to one day at most. The heating mechanism described above can basically be used as is for the continuous heating mechanism. An electric furnace is effective for high-temperature regions, and a hot bath can be used for low-temperature regions.

[0044] (Manufacturing method) As a final explanation of the embodiment, the manufacturing process will be described.

[0045] First, to obtain the desired GIC, the necessary base material and intercalation substance are prepared and weighed. In this weighing, when the stoichiometric ratio at which the GIC after synthesis (after completion of the reaction in the heating continuation step) reaches stage 1 is taken as 100%, the ratio of the intercalation substance to the stoichiometric molar ratio is preferably in the range of 100 to 250%, more preferably 100 to 200%, and even more preferably 100 to 150%.

[0046] After weighing is complete, the base material and the intercalant are introduced into a vessel (introduction step). The intercalant is an alkali metal or alkaline earth metal, some of which react violently with moisture in the air, igniting and emitting smoke. Therefore, after weighing, the intercalant is quickly coated with a protective oil to prevent it from coming into contact with air. Then, the base material, the intercalant coated with the protective oil, the vessel into which they will be introduced, and a cleaning material to remove the protective oil are placed in a glove box. The glove box is then evacuated and then filled with an inert gas such as argon or nitrogen. The protective oil coated on the surface of the intercalant is then wiped away with a cleaning material, after which the base material and the intercalant are introduced into the vessel. In the vapor-phase method, the intercalant and the base material are placed separately to allow contact between the vaporized intercalant and the base material, but in the present invention, they are introduced in a contacting manner.

[0047] Next, the container into which the base material and the intercalant have been introduced is sealed. The reason for sealing is to prevent the intercalant, which is susceptible to reaction with moisture in the air, from reacting with moisture in the air. If the introduction container is a glass tube or the like, the open end can be heated and melted to seal it.

[0048] After the introduction of the base material and the intercalant into the container and sealing are completed, the intercalant is heated and liquefied (heating step). In this heating step, the container is heated in the presence of an inert gas to a temperature sufficient to liquefy the intercalant. The sufficient temperature here is not particularly limited, but may be, for example, a temperature above the melting point. Since only the intercalant is to be liquefied, only the intercalant may be heated, but the intercalant must remain liquid until synthesis is complete. Therefore, to prevent a temperature drop due to contact with the unheated base material and the container and the resulting solidification of the liquid metal, it is preferable to heat not only the intercalant but also the entire container, including the base material.

[0049] After liquefying the intercalant by heating, the liquefied intercalant is brought into contact with the base material, and the liquefied intercalant is intercalated into the base material by capillary action (formation step). At this time, even if the intercalant is present in liquid form at the bottom of a container and the base material is placed in contact with it, the liquefied intercalant will intercalate into the base material by capillary action. However, since this process takes time to complete, the synthesis rate can be improved and the time to complete synthesis can be shortened by stirring the liquefied intercalant and the base material so that the liquefied intercalant comes into contact with the base material that has not yet been intercalated. This stirring method can be achieved by introducing a stirrer into the container and rotating it from the outside, or by shaking the entire container up and down and left and right.

[0050] This heating and stirring is continued until the intercalation substance is intercalated throughout the base material (heating continuation step). For example, when potassium is selected as the intercalation substance and a glass container is used as the container to synthesize KC8, which is a stage 1 GIC of potassium, the synthesis work can be completed by checking that the entire base material has turned golden, which is a characteristic of KC8.

[0051] By using the above-mentioned materials, production apparatus, and production process, it is possible to carry out the present invention, and graphite intercalation compounds of alkali metals or alkaline earth metals can be easily synthesized. [Example]

[0053] The present invention will be explained more specifically with reference to examples. [Example]

[0054] In this Example 1, a method for synthesizing a potassium GIC using potassium, which is one of the alkali metals, will be described.

[0055] Commercially available expanded graphite raw material was heat-treated at 300°C or higher to obtain graphite powder, which would serve as the base material. This was then ground in a mortar or other container to obtain graphite flakes. Graphite powder is bulky and difficult to handle due to its low density, but graphite flakes have the advantage of being thin and plate-like, making them easier to handle. Therefore, the finely powdered expanded graphite was first heat-treated to remove nitrate ions present between layers. The flakes were then lightly crushed in a mortar to obtain flakes.

[0056] A test tube-shaped container was prepared by sealing one end of a glass tube and rolling it up. A recess for sealing was made in the middle of the container. Note that a quartz tube or other material can also be used instead of a glass tube.

[0057] The flakes of expanded graphite (the base material) and potassium metal pieces were then weighed. In this example, the stoichiometric ratio of potassium graphite (KC8), a potassium stage 1 GIC, was set to 100%, and the potassium metal ratio relative to the stoichiometric molar ratio was set to 150%. Experiments to derive this condition were conducted using stoichiometric ratios ranging from 80% to 300% as parameters. Results showed that below 100%, regions where stage 1 was not formed occurred. Furthermore, above 250%, the amount of potassium was excessive, necessitating post-processing to suppress the reaction of potassium with oxygen and moisture after the intercalation compound was produced. Based on these experimental results, the range of stoichiometric ratios of the base material and the intercalation material was determined.

[0058] The weighed flake-form expanded graphite, potassium metal pieces, the prepared glass tube, and a set of cleaning materials for removing the protective oil adhering to the potassium were placed in a glove box, and the glove box was first depressurized. After confirming that a certain degree of vacuum had been reached, argon was introduced into the glove box up to 1 atmosphere. Then, the hand was put into the glove and the surface of the potassium metal pieces was wiped with the cleaning materials. The potassium metal pieces were then introduced into the glass tube, and the expanded graphite was then quickly placed in.

[0059] Thereafter, the glass tube containing the potassium metal pieces and expanded graphite was taken out from the glove box and connected to an atmosphere control system equipped with an argon introduction system.

[0060] At this point, the pressure inside the glass tube was reduced once again. At this time, a vacuum was also evacuated to remove the protective oil on the surface of the potassium metal piece that had not been completely removed by wiping. After sufficient vacuum evacuation had been performed to remove the protective oil that had not been completely wiped off, argon, an inert gas, was introduced.

[0061] The recess of the test tube was then sealed to complete an ampoule-shaped glass tube containing potassium metal pieces and expanded graphite.

[0062] The ampoule was placed in hot water at 70°C to heat and maintain the temperature. This caused the potassium metal flakes to become liquid, and the liquid penetrated the expanded graphite, initiating the synthesis. During this process, the ampoule containing the sample was removed from the hot water and shaken, resulting in droplets of dissolved potassium metal adhering to the small graphite flakes. This shaking caused the potassium metal droplets and the small graphite flakes to uniformly distribute within the ampoule, significantly accelerating the formation of potassium graphite. The reason for setting the temperature at 70°C is due to the melting point of potassium. Since the melting point of potassium is 63.5°C, 70°C was set as the temperature at which potassium becomes sufficiently liquid. Among alkali metals with low melting points, rubidium and cesium have lower melting points than potassium, at 39.5°C and 28.4°C, respectively. In this invention, 60°C is set as the lower limit of the heating step conditions, as it is the temperature at which these low-melting-point metals become sufficiently liquid.

[0063] In addition, although argon gas was used as the inert gas in this example, it was confirmed in subsequent experiments that potassium graphite could also be synthesized using nitrogen as the inert gas. [Example]

[0064] In Example 1, argon gas, an inert gas, was sealed into the glass tube before it was completely sealed. However, it is also possible to seal the glass tube in a vacuum state without introducing the inert gas, to form an ampoule. It was confirmed that potassium graphite could also be synthesized using this ampoule. [Example]

[0065] In Example 1, the ampoule was immersed in hot water at 70°C to heat it, melting the potassium metal and completing the reaction. However, the potassium metal liquefied, and droplets adhered to the entire flake-like expanded graphite. Potassium graphite could also be synthesized by leaving the ampoule containing it in an electric furnace maintained at 150°C.

[0066] Furthermore, even when the droplets were not completely attached to the flake-shaped expanded graphite, potassium graphite could be synthesized by leaving the glass tube in an electric furnace maintained at 150°C, occasionally removing the glass tube, and shaking it. This synthesis method allowed the synthesis to be completed in approximately 3 hours. [Example]

[0067] In Example 1, potassium was used as the intercalation material, but in other examples, it was confirmed that the respective intercalation compounds could also be formed with lithium, which is also an alkali metal, and magnesium, which is an alkaline earth metal.

[0068] In particular, magnesium, an alkaline earth metal, has a melting point of 650°C, which is higher than the heating temperature of 500°C proposed in the present invention. Therefore, by alloying magnesium with sodium, which has a low melting point, the melting point can be lowered by freezing point depression, making it possible to form an intercalation compound of magnesium and graphite even at temperatures below 600°C. When actually producing an intercalation compound of magnesium and graphite, a condition of 400°C, close to the upper heating limit of 500°C in the heating step, was used. [Example]

[0069] In Example 1, expanded graphite was used as the base material, but in other examples, it was confirmed that an intercalation compound can also be formed using commercially available powdered graphite. However, it was also confirmed that the reaction rate was about 10 times slower than when expanded graphite was used. [Example]

[0070] Figure 1 shows a manufacturing system capable of automating the entire manufacturing process. This manufacturing system is equipped with raw material storage chambers A and B. A stores the base material, and B stores the insertion substance, which can be directly supplied to the vessel. It also has an inert gas supply and a gas exhaust system to adjust the atmosphere and pressure during the reaction process. A heater is installed at the bottom of the vessel to liquefy the insertion substance and continue heating until the reaction is complete, and its temperature is controlled by a heater temperature controller. Using this manufacturing system, the base material and insertion substance are introduced into the vessel, and by controlling the atmosphere, heating, and mixing, it is possible to efficiently synthesize GICs in large quantities at high speed without removing them midway. [Explanation of symbols]

[0071] 11. Lower part of manufacturing equipment body 12 Upper part of manufacturing equipment body 13 Heating heater 14 Stirring mechanism 15 Synthetic Materials 16 Synthetic raw material supply

Claims

1. 1. A method for producing an intercalation compound comprising a base material and an intercalation substance, the method comprising: introducing the base material and the intercalation substance into a vessel in the presence of an inert gas; heating the vessel in the presence of the inert gas to a temperature sufficient to cause the intercalation substance to become a liquid; forming the intercalation compound by directly contacting the base material with the liquid to cause a reaction; and continuing to heat the vessel for a time sufficient to complete the reaction.

2. The method for producing an intercalation compound according to claim 1 , further comprising a depressurizing step of depressurizing the inside of the container between the introducing step and the heating step.

3. 3. The method for producing an intercalation compound according to claim 1, wherein the base material is selected from layered carbon materials such as graphite, expanded graphite, and graphite-like materials.

4. 4. The method for producing an intercalation compound according to claim 3, wherein when the base material is a fine powder, it is used after being flaked.

5. 3. The method for producing an intercalation compound according to claim 1, wherein the intercalation substance is one or more metals selected from the group consisting of alkali metals such as lithium, sodium, potassium, rubidium, and cesium, and alkaline earth metals such as magnesium, calcium, strontium, and barium.

6. 3. The method for producing an intercalation compound according to claim 1, wherein the base material and the intercalation substance are introduced in the introducing step in such a manner that the ratio of the intercalation substance to the stoichiometric molar ratio of the base material and the intercalation substance to the stoichiometric molar ratio of the intercalation compound called Stage 1 after the reaction in the heating continuing step is 100%.

7. 3. The method for producing an intercalation compound according to claim 1, wherein in said introducing step, said inert gas is filled so that the content of oxygen and / or moisture which react with said intercalation substance does not exceed 0.1%.

8. 3. The method for producing an intercalation compound according to claim 2, wherein the pressure is reduced so that the pressure does not contain more than 0.1% of oxygen and / or moisture that react with the intercalation substance.

9. 3. The method for producing an intercalation compound according to claim 1, wherein the heating step is performed at a temperature of 60 to 500°C, which is equal to or higher than the temperature at which the intercalation substance becomes liquid.

10. 6. The method for producing an intercalation compound according to claim 5, wherein, when the intercalation substance does not become liquid in a temperature range of 60°C to 500°C, a metal among the metals having a melting point of 100°C or less is used as an additive metal substance for lowering the melting point, and the additive metal substance and the intercalation substance are mixed in a molar ratio of 0.5 to 2 when the additive metal substance is 1, thereby lowering the melting point to a temperature range of 60°C to 500°C.

11. 1. An apparatus for producing an intercalation compound comprising a base material and an intercalation substance, the apparatus comprising: a vessel into which the base material and the intercalation substance are introduced in the presence of an inert gas; a heating mechanism for heating the vessel to a temperature sufficient to cause the intercalation substance to become a liquid in the presence of the inert gas; a direct contact mechanism for forming the intercalation compound by directly contacting and reacting the base material with the liquid; and a heating continuation mechanism for continuing to heat the vessel for a time sufficient to complete the reaction.

12. The apparatus for producing an intercalation compound according to claim 11 , wherein the container is provided with a pressure reducing mechanism for reducing the pressure after the base material and the intercalant are introduced.

13. 13. The apparatus for producing an intercalation compound according to claim 11 or 12, wherein the heating mechanism heats the intercalation substance to a temperature of 60 to 500°C, which is higher than the temperature at which the intercalation substance becomes the liquid.

14. 13. The apparatus for producing an intercalation compound according to claim 11, wherein the direct contact mechanism has a stirring mechanism.

15. 13. The apparatus for producing an intercalation compound according to claim 11 or 12, wherein the heating continuation mechanism heats for a time period of from 1 hour to 1 day, which is sufficient for completing the reaction.

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