JP2016169114A - Method and device for delaminating layered substance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for delaminating a layered substance, in each of which an objective product can be obtained with excellent exfoliation precision at high yield and each of which is suitable for industrial mass production.SOLUTION: The method for delaminating the layered substance comprises the steps of: treating a suspension liquid, which is obtained by suspending the layered substance in a dispersion medium, under high pressure and supplying the treated suspension liquid from a raw material introduction part 2; passing the suspension liquid, which is supplied from the raw material introduction part 2, through a delamination module 3 to perform delamination of the layered substance; and recovering the suspension liquid passed through the delamination module 3 in a recovery part 4. Each of the raw material introduction part 2 and the delamination module 3 has a liquid passage in which the suspension liquid flows and which has 0.15 mm or larger inside diameter but has not another liquid passage having the inside diameter smaller than 0.15 mm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for delamination of a layered material and an apparatus therefor, and more particularly, to a method for producing a single layer or several layers of graphene by delamination of graphite and an apparatus therefor. is there.

  Graphene is a planar two-dimensional material in which six-membered rings of carbon atoms are linked, and forms the basic structure of a layered structure of graphite. Graphene has excellent electrical / electronic properties, mechanical properties, optical properties, thermal properties, mechanical properties, etc., so it can be applied to electronic devices, power storage devices, structural materials, biotechnology, etc. Various applications are expected in a wide range of fields such as biotechnology and medicine.

  As a method for producing graphene, a method of exfoliating graphite is generally used. A typical example is a method of exfoliating graphite oxide oxidized under strong oxidation conditions (Hammers method). In addition, as a method for producing graphene that does not require a strong oxidation treatment step, for example, ultrasonically treating a graphite dispersion solution, inserting a stirring blade or the like into the graphite dispersion solution, and rotating the graphite at high speed, A method of delamination or the like has been proposed.

  Furthermore, in recent years, a method for delamination of graphite using a high-pressure emulsification method has been proposed from the viewpoint of a production method suitable for industrial mass production (Patent Document 1).

  The high-pressure emulsification method is a technology that is used in a wide range of fields such as cosmetics, foods, and pharmaceuticals. A high pressure is applied to a liquid (raw material solution) containing raw materials, and narrow gaps (pores, bottlenecks, etc.) such as nozzles and orifices. High-speed flow (jet flow) is generated by passing, and emulsification, dispersion, homogenization, refinement, etc. are performed by shearing force, impact force, grinding force and the like.

  Various improvement proposals have been made regarding the high-pressure emulsification method and the apparatus therefor. For example, in Patent Document 2, when a shear force is applied to a raw material solution to emulsify and disperse a desired raw material to produce an emulsified dispersion, the amount of pressure (back pressure) applied to the raw material solution is controlled. And the method of suppressing generation | occurrence | production of bubbling by lowering | hanging back pressure of the produced | generated emulsification dispersion liquid in multiple steps by several pressure reduction members is disclosed.

JP 2014-9151 A Japanese Patent No. 4371332

  As described in Patent Document 1, in applying the high pressure emulsification method to the exfoliation of graphite, a penetration type method should be adopted from the viewpoint of applying a shearing force to the surface direction of the graphite particles in the raw material solution. Is considered.

  By the way, the conventional high-pressure emulsification apparatus including the high-pressure emulsifier described in Patent Document 1 and the emulsification dispersion apparatus described in Patent Document 2 includes a pressure generator (pump unit) and a part having a part in which the flow path is extremely narrow ( For example, it is a nozzle or an orifice, and is also referred to as a “nozzle part” hereinafter), and these are essential components for performing the high-pressure emulsification method. The pressure from the pump unit is converted into a jet flow at the nozzle unit, and the liquid ejected from the nozzle unit becomes a turbulent flow while passing through a member called an absorption cell, and an impact force or shear force is applied. Thus, the method described in Patent Document 1 has attempted to apply the high-pressure emulsification method to the exfoliation of graphite by paying attention to the point that a shearing force can be applied to the raw material solution.

  However, when delamination of graphite is performed using such a conventional high-pressure emulsification device, the layer thickness of the obtained graphene varies as in the case of delamination by ultrasonic treatment or mechanical stirring, There is a problem that it is difficult to stably exfoliate graphite with a certain accuracy, for example, the yield of a single layer or several layers of graphene is about several percent.

  In the high-pressure emulsification method, as described above, it is originally assumed that the raw material is homogenized while being crushed to a smaller particle size by acting on the raw material solution in combination of impact force and grinding force. Thus, the device configuration is designed. Therefore, when the high-pressure emulsification method is applied to a layered substance such as graphite, the two-dimensional structure is destroyed by applying an impact force in the plane direction, and the resulting product (for example, graphene) In some cases, the particle size in the surface direction is about half (for example, several μm) of the raw material graphite (eg, several μm), and the flakes or fragments are small. There was also a problem that there was.

  Therefore, in spite of various attempts as described above, even if the conventional high-pressure emulsification method and the high-pressure emulsification apparatus are applied as they are, the layered material is delaminated to obtain a desired product with high accuracy and high. It is difficult to obtain in yield and still further improvements are sought.

  The present invention has been made in view of the circumstances as described above, and is capable of delamination of a layered material that is excellent in delamination accuracy and can be obtained in a high yield and is suitable for industrial mass production. It is an object to provide a method and an apparatus therefor.

  As a result of diligent studies to achieve the above object, the present inventors have come up with a solution means that cannot be assumed at all from the conventionally known high-pressure emulsification method. That is, the present inventors have made an excessive impact in the plane direction of the layered substance in the process in which the jet flow is generated by the operation of passing the raw material solution through the nozzle part, which is an essential component in the conventional high-pressure emulsification apparatus. In other words, the generation condition of the jet flow that is the most fundamental of the high-pressure emulsification method in which an emulsified dispersion is produced by emulsifying and dispersing a desired raw material is from the viewpoint of delamination of layered materials. Found that is not necessarily appropriate.

  Therefore, the present inventors made use of the characteristics of the conventional high-pressure emulsification method, and improved it to a method more suitable for delamination of the layered material, thereby achieving higher accuracy and higher yield than the conventional delamination method, It has been found that graphite can be delaminated into a single layer or several layers of graphene. Further, it has been found that a layered material other than graphite can be delaminated to a desired layer thickness.

  Based on these new findings, the present inventors have made further studies and completed the present invention.

That is, this invention includes the following aspects.
(1) A step in which a suspension obtained by suspending a layered substance in a dispersion medium is subjected to high pressure treatment and supplied from a raw material introduction unit, and the suspension supplied from the raw material introduction unit is passed through an delamination module. A delamination method including a step of delamination of the layered substance and a step of recovering the suspension after passing through the delamination module in a recovery unit, the raw material introduction unit and the delamination module Is a delamination method for laminar substances, characterized in that the liquid passage through which the suspension flows has an inner diameter of 0.15 mm or more and does not have a liquid passage having an inner diameter of less than 0.15 mm.
(2) The method for delamination of a layered material according to (1), wherein the suspension is subjected to high pressure treatment at a pressure of 5 MPa or more.
(3) The delamination module has a structure in which two or more liquid-peeling members are connected in series, and the flow of the suspension is greater than the inner diameter of the liquid-passage channel of the upstream liquid-peeling member. The method for delamination of a layered material according to (1) or (2), wherein the inner diameter of the liquid passage of the downstream liquid-peeling member is large.
(4) The method further includes the step of supplying the suspension recovered by the recovery unit to the raw material introduction unit again and allowing the delamination module to pass therethrough. The method for delamination of a layered material according to any one of the above.
(5) The layered material delamination method according to any one of (1) to (4), wherein the layered material is graphite.
(6) Raw material introduction part for supplying a suspension obtained by suspending a layered substance in a dispersion medium after high-pressure treatment, and passing the suspension supplied from the raw material introduction part to delamination of the layered substance A delamination module, and a delamination apparatus comprising a recovery unit that collects the suspension after passing through the delamination module, wherein the raw material introduction unit and the delamination module include the suspension A laminar substance delamination device characterized in that the flowing liquid passage has an inner diameter of 0.15 mm or more and does not have a liquid passage having an inner diameter of less than 0.15 mm.

  ADVANTAGE OF THE INVENTION According to this invention, the method and apparatus for delamination of a layered substance which are excellent in peeling accuracy and can obtain a target object with a high yield and suitable for industrial mass production are provided.

It is a schematic diagram which shows the delamination apparatus of the layered substance which concerns on one Embodiment of this invention. 2 is an image showing SEM observation results of graphene obtained in Example 1. FIG. (A) Pattern 4, (b) Pattern 5, (c) Pattern 6, (d) Pattern 1, (e) Pattern 2. It is a graph which shows the result of having analyzed the specific surface area and pore distribution by the BET method about the graphene obtained in Example 1, and the raw material graphite. (A) Graphite, (b) Pattern 4, (c) Pattern 5, (d) Pattern 6, (e) Pattern 1. It is an image which shows the TEM observation result of the graphene obtained in Example 2. FIG. It is a Raman spectrum obtained by Raman spectroscopic analysis about the graphene obtained in Example 2, and the raw material graphite. 6 is a characteristic evaluation result of a supercapacitor manufactured using the graphene obtained in Example 2. (A) Cyclic voltammogram (CV curve) of a capacitor (comparative cell) manufactured using raw graphite, (b) CV curve of a supercapacitor (test cell) manufactured using sample graphene, (c) The graph which shows the electrochemical impedance measurement result of the cell for a comparison, and the cell for a test, (d) The graph which shows the charging / discharging characteristic of the cell for a comparison, and a cell for a test.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, as a representative example of the embodiment of the present invention, a case where graphite is assumed as a layered material (hereinafter also referred to as “raw material”) to be delaminated will be described as an example.

  In the present embodiment, the average particle size in the surface direction of the raw material is not particularly limited, but from the viewpoint of obtaining the delamination effect with higher accuracy, it is preferable to consider that the average particle size in the surface direction of the raw material is 200 μm or less. In addition, it is more preferably considered that the average particle size in the surface direction of the raw material is 100 μm or less. Even when the average particle size in the surface direction of the raw material is 200 μm or more, the delamination effect according to the present embodiment can be obtained.

  The dispersion medium used for the preparation of the raw material suspension can be appropriately selected according to the raw material layered material. Examples thereof include water, alcohols such as methanol, ethanol, isopropanol, dimethylformamide, N-methyl-2- Examples include amides such as pyrrolidone (NMP), and mixed solvents thereof. The dispersion medium is, for example, dodecylbenzenesulfonic acid for the purpose of more uniformly dispersing the raw material in consideration of the affinity between the raw material and the dispersion medium, etc., within a range that does not impair the purpose and effect of the present invention. Sodium, sodium dodecyl sulfate, sodium cholate, sodium deoxycholate and the like may be added as a dispersant, and other additives may be added according to the required purpose.

  Although the density | concentration of the raw material in a raw material suspension is not restrict | limited in particular, For example, it is 2-100 mg / mL, Preferably it is 5-50 mg / mL, More preferably, it is 10-30 mg / mL. When the raw material concentration is within the above range, the effect of delamination can be obtained with higher accuracy. Even when the raw material concentration is 100 mg / mL or more, the delamination effect according to the present embodiment can be obtained.

  In addition, in the conventional high-pressure emulsification apparatus provided with a nozzle part, it was difficult to apply a high-viscosity solution, but the delamination apparatus 1 according to the present embodiment does not have a nozzle part as described later. Therefore, even if the viscosity of the raw material suspension is high, the layered material of the raw material can be delaminated to obtain the target product.

  Table 1 below shows an example of the composition of the raw material suspension when the raw material is graphite.

  FIG. 1 is a schematic view showing an apparatus for delaminating a layered material according to an embodiment of the present invention.

  As shown in FIG. 1, the delamination apparatus 1 according to this embodiment includes a raw material introduction unit 2, an delamination module 3, and a recovery unit 4 as main components.

  The delamination method for a layered material according to this embodiment performed using such a delamination device 1 is a high-pressure treatment of a suspension in which the layered material is suspended in a dispersion medium, and is supplied from the raw material introduction unit 2 A step of passing the suspension supplied from the raw material introduction unit 2 through the delamination module 3, and delamination of the layered material, and the suspension after passing through the delamination module 3 A step of collecting by the collecting unit 4 is included.

  In the raw material introduction unit 2, a suspension obtained by suspending a raw material layered material in a dispersion medium is subjected to high pressure treatment and supplied to the delamination module 3. More specifically, in the raw material introduction unit 2, as shown in FIG. 1, the raw material suspension stored in the solution tank 21 is subjected to high pressure treatment by the high pressure pump 22 and supplied to the delamination module 3.

  The pressure applied to the raw material suspension by the high-pressure pump 22 can be appropriately set according to the average particle size in the surface direction of the raw material, the concentration of the raw material in the raw material suspension, the intended use of the product, and the like. When the raw material is graphite, the pressure is, for example, 5 to 150 MPa, preferably 10 to 125 MPa, and more preferably 20 to 100 MPa. As will be described later, when the raw material suspension is passed through the delamination module 3 a plurality of times, the pressure may be adjusted within the above range each time.

  In the above-described high-pressure treatment step, the action of the molecules of the dispersion medium penetrating between the layers of the raw material layered material is strengthened by applying pressure to the raw material suspension by the high-pressure pump 22. At this time, if the force that the dispersion medium molecules permeate exceeds the force acting between the layers of the layered material (for example, van der Waals force), the dispersion medium molecules enter the layers of the layered material one after another (intercalation Be able to). In this way, in the high pressure treatment process, a number of gaps are formed between the layers of the raw material layered material, and the interaction acting between the layers of the layered material is weakened. Progresses efficiently and effectively.

  In the delamination module 3, the raw material suspension supplied from the raw material introduction unit 2 is allowed to pass, and delamination of the raw material layered material is performed.

  More specifically, the delamination module 3 has a structure in which two or more liquid-peeling members are connected in series. In FIG. 1, the delamination module 3 includes three liquid-peeling members 31, 32, The form which has the structure which connected 33 in series is illustrated.

  For example, a straight tube or a spiral tube used as an absorption cell in a conventional high-pressure emulsification device can be applied as the liquid-peeling members 31, 32, and 33.

  Further, in the delamination module 3 shown in FIG. 1, the flow of the liquid separation member downstream of the flow passage of the upstream liquid separation member with respect to the flow of the raw material suspension passing through the delamination module 3 is allowed to pass. The inner diameter of the liquid passage is large. That is, if the inner diameters of the liquid passages of the liquid passage separation members 31, 32, and 33 are D31, D32, and D33, respectively, the relationship of D31 <D32 <D33 is established.

  The lengths of the liquid-peeling members 31, 32, and 33 can be appropriately set according to the average particle size in the surface direction of the raw material, the concentration of the raw material in the raw material suspension, the intended use of the product, and the like. When the raw material is graphite, for example, the range of 5 to 100 cm can be used as a rough standard. In addition, it is preferable to consider appropriately adjusting the lengths of the liquid-peeling members 31, 32, and 33 in accordance with the liquid passage time and the number of liquid passages described later.

  In the present embodiment, the raw material introduction part 2 and the delamination module 3 have an inner diameter of a liquid passage through which the raw material suspension flows is 0.15 mm or more, preferably within a range of 0.15 mm to 1 mm. Moreover, the raw material introduction part 2 and the delamination module 3 do not have a liquid passage having an inner diameter of less than 0.15 mm. That is, in the delamination device 1 according to the present embodiment, it is intended with respect to the surface direction of the layered material of the raw material by adopting a configuration that does not have a nozzle part that is an essential component in the conventional high-pressure emulsification device. The impact force that is not applied is suppressed.

  In the above delamination process, when the raw material suspension passes through the liquid passage of the delamination module 3, a shearing force is applied according to the fluid dynamics. This shear force acts on the gap formed between the layers of the layered material in the above-described high-pressure treatment process, and the interaction acting between the layers of the layered material is further weakened. Then, a single layer or several layers of flake-like structures are peeled off one after another so as to be lifted off the layered material and peeled off. The peeled product is stabilized by quickly adsorbing the dispersion medium molecules on the surface thereof, and the products are prevented from accumulating again and stacked.

  As described above, in the layered material delamination method according to this embodiment, the layered material is efficiently and effectively separated by continuously performing the high-pressure treatment step of the raw material suspension and the subsequent delamination step. The desired product can be obtained in high yield.

  The flow rate of the raw material suspension when passing through the delamination module 3 can be appropriately set according to the average particle size in the surface direction of the raw material, the concentration of the raw material in the raw material suspension, the intended use of the product, and the like. it can. In addition, it is preferable to consider that the speed of the raw material suspension when passing through the delamination module 3 is appropriately adjusted according to the liquid passing time and the number of times of liquid passing described later.

  Further, in the delamination module 3, since a large shearing force is applied to the raw material suspension, the temperature of the suspension may rise during the flow. Therefore, the delamination module 3 can be cooled by a cooling means (not shown) for the purpose of preventing deterioration and peeling due to excessive heating of the raw material, and preventing boiling of the suspension in the collection unit 4. .

  In the recovery unit 4, the raw material suspension after passing through the delamination module 3 is recovered.

  The recovered raw material suspension can be taken out and used as it is as a dispersion of the desired product, and it can be diluted or concentrated to a desired concentration. In addition, the raw material that has not undergone delamination remaining in the recovered raw material suspension can be removed by a generally known separation method such as centrifugation. Moreover, the target product can be obtained by solid-liquid separation of the recovered raw material suspension by filtration or centrifugation, and then drying.

  In the present embodiment, the raw material suspension recovered by the recovery unit 4 can be supplied again to the raw material introduction unit 2 and passed through the delamination module 3. Thus, by passing the delamination module 3 a plurality of times, the delamination accuracy of the layered substance is further improved, and the target product can be obtained with a higher yield. Note that, as described above, the delamination apparatus 1 according to the present embodiment has a configuration that does not have a nozzle portion. Therefore, even if the raw material suspension is passed through the delamination module 3 multiple times, The delamination of the layered material can be performed while suppressing an unintended impact force from being applied to the surface direction of the layered material.

  The time for passing the raw material suspension through the delamination module 3, that is, the time for performing the delamination process (liquid passing time) is the average particle size in the surface direction of the raw material, the concentration of the raw material suspension, the intended use, etc. It can be set appropriately depending on the situation. When the raw material is graphite, for example, it is 15 seconds to 180 minutes, preferably 30 seconds to 150 minutes, and more preferably 1 to 120 minutes. It is understood that the number of times of performing the delamination process (number of times of liquid passing) is appropriately adjusted with the liquid passing time.

  Thus, by using the delamination method and delamination device 1 of the layered material according to the present embodiment, the layered material can be exfoliated with excellent accuracy. For example, when graphite is used as a raw material, A single layer or several layers of graphene can be obtained with high yield.

  Since the graphene obtained in this way is prevented from breaking the two-dimensional structure in the plane direction, the electrical conductivity, transparency, mechanical properties, etc. inherent to graphene are more effectively exhibited and transparent. Applications as electronic materials such as electrodes, and supercapacitors that realize high-speed charging, high output, and large capacity are expected.

  Moreover, according to the delamination method and delamination apparatus 1 of the layered material according to the present embodiment, compared to the conventional delamination method and apparatus, both the batch processing and the continuous processing are performed on a larger scale. Is expected to be possible.

In addition, the delamination method and delamination apparatus 1 of the layered material according to the present embodiment are not limited to the case of using graphite as a raw material, and can be applied to other layered materials. Examples of other layered substances include molybdenum sulfide (IV) (MoS ₂ ), boron nitride (BN), and the like. Here, it is understood that the various conditions described above can be designed as appropriate according to the type, properties, and the like of the raw material layered material.

  As mentioned above, although embodiment of this invention was explained in full detail, description of said structural requirement is an example (representative example) of embodiment of this invention, and a concrete form is not restricted to these embodiment. However, design changes and the like within the scope not departing from the gist of the present invention are included in the present invention.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to these Examples.

  In this example, the delamination module 3 of the delamination apparatus 1 illustrated in FIG. 1 was configured as shown in Table 2, and a graphite delamination test was performed. In addition, the straight tube and spiral tube used as the liquid permeation | separation peeling members 31, 32, and 33 used the thing of length 30cm.

  In this example, a sample for SEM observation was prepared by dropping several mL of a graphene dispersion on a Si wafer. SEM observation was performed using a field emission scanning electron microscope (FE-SEM, JSM-6500, JEOL).

  A sample for TEM observation was prepared by dropping several mL of a graphene dispersion on a holey carbon grid. TEM observation was performed at 200 kV using JEOL 2100 (JEOL).

<Example 1>
Using the delamination device provided with the delamination module of each pattern shown in Table 2, the raw material suspension No. 1 shown in Table 1 was used. 2 was supplied from the raw material supply section at a pressure of 100 MPa, and the delamination module was continuously passed 10 times.

  The recovered raw material suspension was centrifuged at 6000 rpm for 60 minutes to remove the graphite precipitate that was not delaminated to obtain a graphene dispersion. Further, the obtained dispersion was vacuum filtered to remove the dispersion medium, and the residue was dried at 120 ° C. to obtain a graphene powder.

  The SEM observation result of the obtained graphene is shown in FIG. 2A to 2E respectively correspond to patterns 4 to 6 and patterns 1 to 2 shown in Table 2 ((a) pattern 4, (b) pattern 5, (c) pattern 6, (d) ) Pattern 1, (e) Pattern 2).

  From the result of FIG. 2, compared with the patterns 4 to 6 (FIGS. 2A to 2C) having the nozzle portion, patterns 1 and 2 having no nozzle portion (FIGS. 2D and 2E) ), Graphene having a larger grain size in the plane direction is obtained.

  Further, FIG. 3 shows the results of analyzing the specific surface area and pore distribution of the obtained graphene and raw graphite by the BET method. FIGS. 3A to 3E respectively correspond to graphite, patterns 4 to 6 and pattern 1 shown in Table 2 ((a) graphite, (b) pattern 4, (c) pattern 5, and (d). Pattern 6, (e) Pattern 1). The analysis was performed using AUTOSORB (Cantachrome Instruments).

From the result of FIG. 3, the specific surface area of the raw material graphite is 19.6 m ² / g (FIG. 3A), and in the case of patterns 4 to 6 (FIGS. 3B to 3D) having nozzle portions The graphene has a specific surface area of only about 30.0 to 37.0 m ² / g, whereas in the pattern 1 having no nozzle portion (FIG. 3E), 63.5 m ² / g. It can be seen that graphene having a high specific surface area with g is obtained.

  Thus, it was confirmed that delamination of graphite can be performed with high accuracy by passing a high-pressure-treated graphite suspension using a delamination module having no nozzle portion.

<Example 2>
Using the delamination device 1 provided with the delamination module 3 having the pattern 2 shown in Table 2, the raw material suspension No. 1 shown in Table 1 was used. 2 was supplied from the raw material supply section at a pressure of 100 MPa, and the delamination module was continuously passed through for 120 minutes. The flow rate of the raw material suspension at the time of passing was about 140 ml / min.

  The recovered raw material suspension was centrifuged at 6000 rpm for 60 minutes to remove the graphite precipitate that was not delaminated to obtain a graphene dispersion. The obtained dispersion was vacuum filtered to remove the dispersion medium, and the residue was dried (120 ° C.) to obtain graphene powder. The yield of the obtained graphene was about 15% (corresponding to a concentration of about 1.5 mg / mL).

  FIG. 4 is an image showing a TEM observation result of the obtained graphene. FIG. 4 shows that the graphene obtained in Example 2 is a thin-layer graphene having a thickness in the layer direction of less than 4 nm and at least less than 10 layers.

  The obtained graphene was subjected to Raman spectroscopic analysis as follows.

  As an analysis sample, graphene was deposited on a Si wafer. Moreover, the sample for a comparison was produced using the raw material graphite.

  FIG. 5 shows the Raman spectra of the comparative sample (a) and the analytical sample (b).

As shown in FIG. 5 (a), in the comparative sample (raw material graphite), two characteristic peaks were confirmed at 1580 cm ⁻¹ (G peak) and 2714 cm ⁻¹ (2D peak), in addition to graphite. A weak band attributed to the boundary of the crystallite layer is observed at 1355 cm ⁻¹ (D peak). On the other hand, as shown in FIG.5 (b), in the sample for analysis (graphene obtained in the present Example), it turns out that the intensity | strength of said D peak is increasing notably.

Here, when the ratio of the D peak to the G peak (I _D / I _G ) is calculated, it is 0.15 for the raw material graphite and 0.55 for the graphene obtained in this example. This I _D / I _G value is significantly smaller than previously reported for reduced graphene oxide (I _D / I _G > 1), which means that the layered material delamination method according to the present invention However, it has shown that the destruction of the two-dimensional structure of the surface direction used as the foundation of a layered substance is suppressed effectively.

The I _{D /} I _G value of graphene obtained by comparing the raw material graphite in this embodiment is a slight increase is believed to be due to the edge effect of the resulting graphene.

  Further, comparing FIG. 5A and FIG. 5B, it can be seen that the graphene obtained in this example shows a change in the 2D peak.

The 2D peak of the raw material graphite, the peak in 2714cm ^-1, has a shoulder to 2693cm ^-1, which are characteristic peak profile a stacked structure of the graphite. On the other hand, the 2D peak of graphene obtained in this example is slightly shifted to the low wavenumber side (2697 cm ⁻¹ ) and has a symmetrical shape. This strongly suggests that the graphene obtained in this example is occupied by a single layer or several layers of flaky structures.

<Production and characteristics evaluation of supercapacitors>
Using the graphene obtained in Example 2 (hereinafter referred to as “sample graphene”), a supercapacitor was produced according to the following procedure, and its characteristics were evaluated.

  Sample graphene and poly (tetrafluoroethylene) (PTFE) were mixed in NMP at a mass ratio of 90:10. Next, this solution was suction filtered on a porous membrane (Hydrophilic, 0.2 μm PTFE) to form an electrode membrane. This electrode film was vacuum-dried at 25 ° C. for 24 hours and then cut to a diameter of 15 mm to produce an electrode having a weight of about 0.8 mg.

As a test cell, ionic liquid (1-ethyl-3-methylimidazolium-bis (trifluoromethylsulfonyl) imide, EMI-TFSI) is used for the electrolyte, glass fiber is used for the separator, and current collector is used. An aluminum foil coated with carbon (Exopack ^™ 0.5 mil double-sided coating) was used as a conductive material. The test cell was assembled in a glove box under an argon gas atmosphere. In addition, a comparative cell was produced using raw material graphite instead of sample graphene.

  For the test cell and the comparative cell, cyclic voltammetry (CV), electrochemical impedance measurement (EIS), and galvanostatic measurement (GC) were performed using a VMP3 multichannel potentiostat / galvanostat (Biologic).

  FIG. 6 summarizes the results of characteristic evaluation. FIG. 6A is a cyclic voltammogram (CV curve) of a capacitor (comparison cell) fabricated using raw graphite, and FIG. 6B is a diagram of a supercapacitor fabricated using sample graphene (test cell). It is a CV curve. FIG. 6C is a graph showing the electrochemical impedance measurement results of the comparative cell and the test cell, and FIG. 6D is a graph showing the charge / discharge characteristics of the comparative cell and the test cell.

  It should be noted that, as shown in FIG. 6D, the specific capacitance of the comparison cell was 12 F / g, whereas the test cell showed a specific capacitance of 75 F / g. Thus, the increase in specific capacitance confirmed for the test cell is brought about by the fact that the specific surface area of the sample graphene is larger than that of the raw graphite, as can be understood from FIG. It is thought that it was done.

DESCRIPTION OF SYMBOLS 1 Delamination apparatus 2 Raw material introduction part 21 Solution tank 22 High pressure pump 3 Delamination module 31, 32, 33 Liquid-peeling member 4 Collection | recovery part

Claims (6)

A step of high-pressure processing a suspension in which a layered substance is suspended in a dispersion medium, and supplying the suspension from a raw material introduction unit;
The step of passing the suspension supplied from the raw material introduction unit through the delamination module to perform delamination of the layered material, and collecting the suspension after passing through the delamination module in the recovery unit A delamination method comprising a step of:
The raw material introduction part and the delamination module are characterized in that the liquid passage through which the suspension flows has an inner diameter of 0.15 mm or more and does not have a liquid passage having an inner diameter of less than 0.15 mm. A method for delamination of layered materials.   The method for delamination of a layered material according to claim 1, wherein the suspension is subjected to high pressure treatment at a pressure of 5 MPa or more.   The delamination module has a structure in which two or more liquid-peeling members are connected in series, and is downstream of the inner diameter of the liquid-flow path of the upstream liquid-peeling member with respect to the flow of the suspension. The method for delaminating a layered substance according to claim 1 or 2, wherein the inner diameter of the liquid passage of the liquid peeling member is large.   4. The method according to claim 1, further comprising a step of supplying the suspension recovered by the recovery unit to the raw material introduction unit again and passing the delamination module. A method for delamination of the layered material described.   The layered material delamination method according to any one of claims 1 to 4, wherein the layered material is graphite. A raw material introduction section for supplying a suspension obtained by suspending a layered material in a dispersion medium after high-pressure treatment,
A delamination module for delamination of the layered material by passing the suspension supplied from the raw material introduction unit; and a recovery unit for collecting the suspension after passing through the delamination module. A delamination device,
The raw material introduction part and the delamination module are characterized in that the liquid passage through which the suspension flows has an inner diameter of 0.15 mm or more and does not have a liquid passage having an inner diameter of less than 0.15 mm. Layer delamination equipment.