Coated metal sheet for producing graphene

Abstract

The invention relates to a method for producing graphene (3), in which a carrier material is provided, in which the graphene (3) is produced on the carrier material by a chemical vapor deposition method, in which the graphene (3) is peeled off from the carrier material, in particular by a bubble transfer process, and transferred to a storage film (4) for storage. According to the invention, the provided carrier material is a copper-plated metal sheet. The invention also relates to graphene (3) produced according to the method and to a copper-plated metal sheet for use in the method.

Description

[0001] This invention relates to a method for preparing graphene, graphene prepared by the method, and copper-plated metal sheets used for preparing graphene.

[0002] Graphene is an allotrope of carbon, consisting of a single layer of atoms arranged in a hexagonal lattice structure. Due to its excellent material properties, graphene has been proposed for many applications. However, its practical applications are currently very limited due to its high production cost. Several methods exist for preparing graphene: Initially, graphene was mechanically extracted from graphite through exfoliation. The drawback of this method is that it can only yield small areas containing a large proportion of graphene oxide.

[0003] Chemical vapor deposition (CVD) can produce graphene with larger areas and higher quality. For example, P. Trinsoutrot et al., Surface and Coatings Technology, 2013, 230, 87-92, describe the preparation of graphene by CVD. US 2011 / 195207 A1 discloses an apparatus for the continuous preparation of graphene by CVD.

[0004] For example, a similar method for preparing graphene is described in WO 2013 154997 A1. Here, graphene is deposited on a copper film using CVD. The copper film is then peeled off, and the graphene is transferred to a titanium film. A disadvantage of this method is that, on the one hand, the graphene's structure is partially destroyed due to the different cooling of the copper and graphene, resulting in poor graphene quality. Furthermore, the production process is very complex and expensive, especially due to the large amount of copper consumed.

[0005] DE 10 2013 220 158 A1 describes a method to partially overcome these drawbacks. Here, a copper strip is first provided. Graphene is deposited onto this copper strip via CVD. The heated graphene is then transferred to a transfer strip for cooling, and the copper strip is peeled off using a bubble transfer process. For example, L. Gao et al., Nature Communications, DOI: 10.1038 / NCQMMS1702 describe the bubble transfer process. After cooling, the graphene is transferred from the transfer strip to another film for storage. This allows for the preparation of higher quality graphene. DE 10 2013 220 158 further describes the ability to reuse both the copper strip and the transfer strip. However, even with this method, repeated handling can damage the graphene. Another drawback is the low tensile strength of the copper strip, which makes reuse difficult, and the process can only be performed at low strip speeds.

[0006] CN 110040726 A1 proposes another possibility to overcome the drawback of different cooling rates between copper and graphene. It discloses the preparation of graphene on a copper-nickel alloy. However, unavoidable minor fluctuations in the alloy composition already lead to uneven graphene deposition. This is even exacerbated during cooling, as the graphene deforms due to the different coefficients of thermal expansion of the elements. Therefore, it is impossible to prepare graphene with a large and uniform area using this method.

[0007] Currently, the production speed of graphene is extremely slow, at 0.12 meters per minute. Therefore, graphene films, especially high-quality large-area films, are very expensive.

[0008] Therefore, the object of this invention is to achieve faster and more cost-effective graphene production.

[0009] This objective is achieved in a method for preparing graphene by using a copper-plated metal sheet as the carrier material. The method provides a carrier material, on which graphene is prepared by chemical vapor deposition, wherein the graphene is peeled off from the carrier material, particularly by a bubble transfer process, and transferred to a storage membrane for storage.

[0010] The metal sheet has higher tensile strength, allowing the process to be carried out at higher speeds and the carrier material to be reused more frequently. This significantly reduces costs. In this invention, copper plating refers to a copper layer containing at least 90% by weight, preferably at least 99% by weight, with the remainder being possible impurities.

[0011] The method of this invention can yield graphene composed of only three to ten atomic layers, particularly three to five atomic layers. The thickness of this graphene is less than 1 mm. Simultaneously, graphene of at least 10 cm⁻¹ can be prepared. 2 Especially at least 100 cm 2 The graphene has a large surface area. Particularly preferably, the graphene exists in the form of continuous bands. Therefore, a method is provided capable of preparing graphene with a large and uniform area. Consequently, the graphene exhibits high thermal and electrical conductivity.

[0012] To prepare particularly high-quality graphene, the provided metal sheets can be made with a coefficient of thermal expansion of less than 20 in the range of 20–400°C

[10] . -6 [m / (mx K)], especially below 15

[10] -6 m / (mx K)], preferably below 12

[10] -6The graphene is composed of an alloy of [m / (m x K)], wherein the copper layer is planar or has a 111 orientation. Due to the low coefficient of thermal expansion and uniform orientation of copper, damage to the graphene structure during cooling on the carrier material can be avoided. The resulting graphene is therefore deposited particularly uniformly and retains a coherent, uniform structure and constant layer thickness even after cooling.

[0013] To prepare particularly large-area graphene, it is advantageous to apply a copper layer using the BIAS method. For this purpose, a voltage, particularly a negative voltage, is applied to the substrate during PVD plasma coating. The resulting copper layer is exceptionally uniform and adheres very well.

[0014] In a particularly suitable method, the metal sheet provided is made of steel alloy or aluminum alloy.

[0015] In order to enable this method to be carried out in a particularly cost-effective manner, the provided metal sheet may comprise an alloy having the following composition (wt%): 0.01 to 0.20 carbon (C), 30 to 40 nickel (Ni), 0.01 to 0.60 manganese (Mn), 0.01 to 0.40% silicon (Si) <0.06 phosphorus (P), <0.04 Sulfur (S), Optional containing 0 to 0.25 Chromium (Cr), 0 to 0.50 Cobalt (Co), 0 to 0.20 Aluminum (Al), 0 to 0.50 Molybdenum (Mo), 0 to 0.50 Copper (Cu), 0 to 0.30 Vanadium (V), 0 to 0.20 Titanium (Ti), 0 to 0.20 Niobium (Nb) 0 to 0.005 Boron (B), 0 to 0.015 Nitrogen (N), 0 to 0.01 Calcium (Ca), In addition to the remaining iron (Fe) and unavoidable impurities due to the manufacturing process.

[0016] This alloy is used in a variety of applications and is produced in large quantities, thus keeping the production cost of the metal sheets low. Furthermore, this alloy is particularly suitable for the method of this invention because a very uniform copper layer can be produced when coated with copper. This enables the preparation of exceptionally high-quality graphene.

[0017] In particular, steel grade 1.3912 is especially suitable here because of its particularly low coefficient of thermal expansion. Steel grade 1.4412 is also very suitable.

[0018] If the provided carrier material has a planar copper layer or a 111-oriented copper layer, then particularly high-quality graphene can be prepared. This avoids the structural irregularities in graphene.

[0019] To prepare exceptionally high-quality graphene, a copper layer is deposited on a metal sheet using a suitable process, particularly physical vapor deposition (PVD), to provide a carrier material. This allows for the production of precisely defined copper layers with uniform thickness and orientation. Therefore, planar copper layers or 111-oriented copper layers can be obtained via PVD. Furthermore, PVD enables the deposition of copper onto metal sheets at high speeds ranging from 10 to 180 meters per minute to prepare the carrier material.

[0020] This method of graphene preparation is particularly resource-efficient and cost-effective if the carrier material is provided after graphene exfoliation and reused to prepare graphene again. This allows for a closed-loop process where the carrier material can be directly reused. If the copper coating is damaged after multiple passes, the copper can be removed from the metal sheet by acid etching. The collected copper can be reused to coat the metal sheet, for example, using PVD plasma methods. Similarly, the cleaned metal sheet can be coated with copper again. For example, plasma etching is suitable for cleaning the metal sheet.

[0021] Since the above method can produce particularly uniform and high-quality graphene, the graphene prepared by this method is also according to the present invention. The graphene according to the present invention consists of only three to ten atomic layers, particularly three to five atomic layers. Therefore, the thickness of this graphene is less than 1 mm. Simultaneously, graphene with a thickness of at least 10 cm can be prepared. 2 Especially at least 100 cm 2 The graphene area is specified. The graphene is particularly preferably present in the form of continuous strips. To prevent graphene oxidation, it can be stored under a protective atmosphere, such as nitrogen or argon.

[0022] According to the invention, there is also a copper-plated metal sheet, particularly a metal strip, for use in the method according to any one of claims 1 to 7, wherein the metal sheet has a coefficient of thermal expansion of less than 20 in the range of 20–400°C

[10] . -6 [m / (mx K)], especially below 15

[10] -6 m / (mx K)], preferably below 12

[10] -6 [m / (mx K)] The low coefficient of thermal expansion prevents damage to the graphene structure during cooling on the carrier material.

[0023] Highly high-quality graphene can be produced cost-effectively using copper-plated metal sheets.

[0024] It is particularly suitable for use in copper-plated metal sheets for preparing graphene, the metal sheets being made of steel alloy or aluminum alloy.

[0025] To obtain the most uniform graphene structure possible, even upon cooling, it is particularly suitable that the alloy has the following composition (wt%): 0.01 to 0.20 carbon (C), 30 to 40 nickel (Ni), 0.01 to 0.60 manganese (Mn), 0.01 to 0.40% silicon (Si) <0.06 phosphorus (P), <0.04 Sulfur (S), Optional includes: 0 to 0.25 Chromium (Cr), 0 to 0.50 Cobalt (Co), 0 to 0.20 Aluminum (Al), 0 to 0.50 Molybdenum (Mo), 0 to 0.50 Copper (Cu), 0 to 0.30 Vanadium (V), 0 to 0.20 Titanium (Ti), 0 to 0.20 Niobium (Nb) 0 to 0.005 Boron (B), 0 to 0.015 Nitrogen (N), 0 to 0.01 Calcium (Ca), In addition to the remaining iron (Fe) and unavoidable impurities due to the manufacturing process.

[0026] Steel 1.3912 is particularly suitable here because, on the one hand, its low coefficient of thermal expansion prevents structural damage during graphene cooling; on the other hand, copper can be applied to the material very uniformly. Steel 1.4412 can also be used.

[0027] Highly high-quality graphene can be achieved by using copper-plated metal sheets in which the copper layer is planar or has a 111 orientation.

[0028] To enable the copper-plated metal sheet to be frequently reused as a carrier material, the thickness of the copper layer can range from 0.1 μm to 100 μm. It has been found that a thickness range of 1 μm to 75 μm may be particularly advantageous, as it can improve adhesion promotion at a relatively thin layer thickness while ensuring scratch resistance and abrasion resistance.

[0029] Since the aforementioned copper-plated metal sheet is particularly suitable for preparing graphene according to the method described above, especially the CVD method, its use as a carrier material in this method is also according to the present invention. This allows for the cost-effective preparation of high-quality graphene.

[0030] The present invention will be described by way of example below with reference to the accompanying drawings, but this does not limit the overall concept of the invention: Figure 1 A schematic diagram of an exemplary method is shown.

[0031] Figure 1 The illustration shows that a metal sheet, referred to as metal strip 1 in the illustrated embodiment, is first coated with copper. In the illustrated embodiment, metal strip 1 is made of steel 1.3912. The copper coating 2 is applied using physical vapor deposition (PVD). In the illustrated embodiment, the thickness of copper layer 2 is from 0.1 μm to 100 μm. Furthermore, in the illustrated embodiment, copper layer 2 has a uniform orientation.

[0032] Graphene 3 was prepared by chemical vapor deposition (CVD) on a copper-plated metal strip used as a carrier material, and deposited onto the copper layer 2 with high quality. After cooling, the graphene 3 was transferred to a storage film 4 for storage and then peeled off from the substrate material using a bubble transfer process. The carrier material can then be reused, and the graphene 3 can be re-deposited onto the copper coating 2.

[0033] If the copper layer 2 wears off after frequent use of the carrier material, the copper can be removed by acid pickling. This copper can be recovered from the solution and reused for coating metal strip 1 after cleaning. Metal strip 1 can also be cleaned after acid pickling and then coated with copper again.

[0034] This could provide a resource-saving and cost-effective method for preparing high-quality graphene.

Claims

1. A method for preparing graphene (3), wherein a carrier material is provided, wherein graphene (3) is prepared on the carrier material by chemical vapor deposition, wherein the graphene (3) is peeled off from the carrier material, particularly by a bubble transfer process, and transferred to a storage membrane (4) for storage, characterized in that, The provided carrier material is a copper-plated metal sheet.

2. The method according to claim 1, wherein the provided metal sheet (1) is made of an alloy having a coefficient of thermal expansion of less than 20 in a temperature range of 20-400°C [10]. -6 m / (mx K)], preferably below 15 [10] -6 m / (mx K)], especially preferably below 12 [10] -6 m / (mx K)].

3. The method according to claim 1 or 2, wherein the provided metal sheet (1) is made of steel alloy or aluminum alloy.

4. The method according to any one of claims 1 to 3, wherein the provided metal sheet (1) comprises an alloy having the following composition (wt%): 0.01 to 0.20 carbon (C), 30 to 40 nickel (Ni), 0.01 to 0.60 manganese (Mn), 0.01 to 0.40% silicon (Si) < 0.06 phosphorus (P), < 0.04 Sulfur (S), Optional containing 0 to 0.25 Chromium (Cr), 0 to 0.50 Cobalt (Co), 0 to 0.20 Aluminum (Al), 0 to 0.50 Molybdenum (Mo), 0 to 0.50 Copper (Cu), 0 to 0.30 Vanadium (V), 0 to 0.20 Titanium (Ti), 0 to 0.20 Niobium (Nb) 0 to 0.005 Boron (B), 0 to 0.015 Nitrogen (N), 0 to 0.01 Calcium (Ca), And the remainder of iron (Fe) and unavoidable impurities due to the manufacturing process, wherein the metal sheet (1) is in particular made of steel 1.3912 or steel 1.4112.

5. The method according to any one of claims 1 to 4, wherein the provided carrier material has a planar copper layer (2) or a copper layer (2) with an 111 orientation.

6. The method according to any one of claims 1 to 5, wherein the preparation of the carrier material is carried out by applying a copper layer (2) onto a metal sheet (1) by vapor deposition, particularly physical vapor deposition, particularly at a speed of 10 to 180 m / min.

7. The method according to any one of claims 1 to 6, wherein after the graphene (3) is exfoliated, the carrier material is provided for use again in the preparation of graphene.

8. Graphene (3) consisting of three to ten atomic layers, especially three to five atomic layers, wherein the area of ​​the graphene is at least 10 cm². 2 Especially at least 100 cm 2 Furthermore, the graphene is preferably present in the form of a continuous band.

9. A copper-plated metal sheet, particularly a metal strip, for use in the method according to any one of claims 1 to 7, wherein the metal sheet (1) has a coefficient of thermal expansion of less than 20 in a temperature range of 20-400°C [10] -6 m / (mx K)], preferably below 15 [10] -6 m / (mx K)], especially preferably below 12 [10] -6 m / (mx K)], wherein the copper layer (2) is planar oriented or has a 111 orientation.

10. The copper-plated metal sheet according to claim 9, wherein the metal sheet (1) is made of steel alloy or aluminum alloy.

11. The copper-plated metal sheet according to claim 10, wherein the alloy has the following composition (wt%): 0.01 to 0.20 carbon (C), 30 to 40 nickel (Ni), 0.01 to 0.60 manganese (Mn), 0.01 to 0.40% silicon (Si) < 0.06 phosphorus (P), < 0.04 Sulfur (S), Optional containing 0 to 0.25 Chromium (Cr), 0 to 0.50 Cobalt (Co), 0 to 0.20 Aluminum (Al), 0 to 0.50 Molybdenum (Mo), 0 to 0.50 Copper (Cu), 0 to 0.30 Vanadium (V), 0 to 0.20 Titanium (Ti), 0 to 0.20 Niobium (Nb) 0 to 0.005 Boron (B), 0 to 0.015 Nitrogen (N), 0 to 0.01 Calcium (Ca), And the remainder of iron (Fe) and unavoidable impurities due to the manufacturing process, wherein the metal sheet (1) is in particular made of steel 1.3912 or steel 1.4112.

12. The copper-plated metal sheet according to any one of claims 9 to 11, wherein the thickness of the copper layer (2) is from 0.1 μm to 100 μm, particularly from 1 μm to 75 μm.

13. The copper-plated metal sheet according to any one of claims 9 to 12, wherein graphene (3), particularly the graphene (3) according to claim 8, is disposed on the copper layer (2).

14. Copper-plated metal sheets are used as carrier materials for depositing graphene by chemical vapor deposition (3), particularly for use in the method according to any one of claims 1 to 7.

15. The use according to claim 14, wherein the copper-plated metal sheet is formed according to any one of claims 9 to 12.

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