Metal substrate for growing carbon nanowalls, metal substrate with carbon nanowalls, and methods for manufacturing these

Abstract

To provide a metal substrate for carbon nanowall growth, a metal substrate with carbon nanowalls, and a method for manufacturing them, which are capable of depositing carbon nanowalls under low-temperature conditions of the order of 0°C to 500°C.SOLUTION: A negative electrode current collector N1 is a metal substrate for carbon nanowall growth. The negative electrode current collector N1 has a first surface N1a. The negative electrode current collector N1 has a plurality of projections PR1 on the first surface N1a. The area of the projection region of the projections PR1 projected onto the first face N1a is between 10 nm2 and 10000 nm2. The density of the projections PR1 is between 1 piece / μm2 and 1000 pieces / μm2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technical field of the present specification relates to a metal substrate for growing carbon nanowalls, a metal substrate with carbon nanowalls, and a method for producing the same, which are used in an electricity storage device. [Background technology]

[0002] Examples of chargeable and dischargeable electricity storage devices include secondary batteries, electric double layer capacitors, etc. Furthermore, examples of electricity storage devices that utilize lithium ions include lithium ion secondary batteries, lithium ion primary batteries, and lithium ion capacitors.

[0003] For example, Patent Document 1 discloses a lithium-ion secondary battery having a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte. It discloses a technology using lithium cobalt oxide or lithium nickel oxide as the positive electrode active material and carbon as the negative electrode active material (claims and examples of Patent Document 1). Graphite is often used as the carbon material. Graphite can absorb or release one lithium ion per six carbon atoms in a six-membered ring. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 2668678 Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventors are currently researching and developing a technology for using carbon nanowalls in the negative electrode of lithium-ion secondary batteries. However, in order to form a carbon nanowall film on a copper foil negative electrode current collector or an aluminum foil positive electrode current collector, the film must be formed under high-temperature conditions of approximately 500°C to 600°C. In this case, stress is generated between the copper foil or aluminum foil and the carbon nanowalls due to the difference in thermal expansion coefficients when the copper foil or aluminum foil is heated before film formation or when the copper foil or aluminum foil is cooled after film formation. In some cases, wrinkles are formed on the negative electrode current collector or positive electrode current collector.

[0006] The problem that the technology of this specification aims to solve is to provide a metal substrate for growing carbon nanowalls, a metal substrate with carbon nanowalls, and methods for manufacturing these, which are capable of forming carbon nanowalls under low-temperature conditions of approximately 0°C or higher and lower than 500°C. [Means for solving the problem]

[0007] One aspect of the present invention is a metal substrate having a first surface; carbon nanowalls formed on the first surface of the metal substrate; and The metal substrate is a plurality of protrusions on the first surface; The area of a projected region of each of the protrusions projected onto the first surface is 10nm 2 More than 10000nm 2 is as follows: The density of the protrusions is 1 piece / μm 2 More than 1000 pieces / μm 2 is as follows: The carbon nanowalls are The protrusion is straddled. The carbon nanowall-containing metal substrate is

[0008] this goldThe metal substrate has protrusions on the first surface. The protrusions serve as starting points for generating carbon nanowalls. In this way, the protrusions act, for example, as a catalyst. Therefore, the metal substrate can be grown at a low temperature of 0°C or higher but lower than 500°C. Metal substrate Carbon nanowalls can be deposited on the surface of the substrate. [Effects of the Invention]

[0009] This specification provides a metal substrate for growing carbon nanowalls, which allows carbon nanowalls to be formed under low-temperature conditions of approximately 0° C. or higher and lower than 500° C., a metal substrate with carbon nanowalls, and methods for producing these. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a lithium-ion secondary battery LiB1 of a first embodiment. [Figure 2] 2 is a diagram schematically illustrating a cross section of a carbon nanowall CNW1 of the lithium ion secondary battery LiB1 according to the first embodiment. FIG. [Figure 3] 2 is a diagram conceptually showing the structure of a carbon nanowall CNW1 of the lithium ion secondary battery LiB1 of the first embodiment. FIG. [Figure 4] 1 is a schematic diagram showing the configuration of a manufacturing apparatus for growing carbon nanowalls CNW1 in the lithium ion secondary battery LiB1 of the first embodiment. FIG. [Figure 5] This is a scanning electron microscope photograph (part 1) showing the surface of a copper foil after irradiating it with hydrogen radicals. [Figure 6] 1 is a scanning electron microscope photograph showing the surface of carbon nanowalls grown at a heater set temperature of 500°C. [Figure 7] 1 is a scanning electron microscope photograph showing a cross section of carbon nanowalls grown at a heater temperature of 500°C. [Figure 8] 1 is a scanning electron microscope photograph showing the surface of carbon nanowalls grown at a heater set temperature of 400°C. [Figure 9]1 is a scanning electron microscope photograph showing a cross section of carbon nanowalls grown at a heater temperature of 400°C. [Figure 10] 1 is a scanning electron microscope photograph showing the surface of carbon nanowalls grown at a heater temperature of 300° C. [Figure 11] 1 is a scanning electron microscope photograph showing a cross section of a carbon nanowall grown at a heater temperature of 300°C. [Figure 12] 1 is a scanning electron microscope photograph showing the surface of carbon nanowalls grown at a heater temperature of 200° C. [Figure 13] 1 is a scanning electron microscope photograph showing a cross section of a carbon nanowall grown at a heater temperature of 200° C. [Figure 14] 1 is a scanning electron microscope photograph showing the surface of carbon nanowalls grown at a heater temperature of 20° C. [Figure 15] 1 is a scanning electron microscope photograph showing a cross section of a carbon nanowall grown at a heater temperature of 20° C. [Figure 16] 1 is a scanning electron microscope photograph showing the surface of carbon nanowalls grown at a substrate temperature of 500° C. without irradiation with hydrogen radicals. [Figure 17] 1 is a graph showing the relationship between the capacity and voltage of a lithium ion secondary battery having a negative electrode in which carbon nanowalls are grown on copper foil at a substrate temperature of 500° C. [Figure 18] 1 is a graph showing the relationship between the capacity and voltage of a lithium ion secondary battery having a negative electrode in which carbon nanowalls are grown on copper foil at a substrate temperature of 400° C. [Figure 19] 1 is a graph showing the relationship between the capacity and voltage of a lithium ion secondary battery having a negative electrode in which carbon nanowalls are grown on copper foil at a substrate temperature of 300° C. [Figure 20] 1 is a graph showing the relationship between the capacity and voltage of a lithium ion secondary battery having a negative electrode in which carbon nanowalls are grown on copper foil at a substrate temperature of 200° C. [Figure 21]1 is a graph showing the relationship between the capacity and voltage of a lithium ion secondary battery having a negative electrode in which carbon nanowalls are grown on copper foil at a substrate temperature of 20° C. [Figure 22] This is a scanning electron microscope photograph (part 2) showing the surface of a copper foil after irradiating it with hydrogen radicals. [Figure 23] This is a scanning electron microscope photograph (part 3) showing the surface of a copper foil after irradiating it with hydrogen radicals. [Figure 24] 24 is a graph showing the measurement results of the unevenness on the line in FIG. 23. [Figure 25] 10 is a graph showing the relationship between the amount of hydrogen supplied and the number of protrusions having an area of 10 nm 2 or more and 100 nm 2 or less. [Figure 26] 10 is a graph showing the relationship between the amount of hydrogen supplied and the number of protrusions having an area of 100 nm 2 or more and 1000 nm 2 or less. [Figure 27] 10 is a graph showing the relationship between the amount of hydrogen supplied and the number of protrusions having an area of 1000 nm 2 or more and 10000 nm 2 or less. [Figure 28] 10 is a graph showing the relationship between the amount of hydrogen supplied and the number of protrusions. [Figure 29] 10 is a graph showing the relationship between the magnitude of the bias and the number of protrusions having an area of 10 nm 2 or more and 100 nm 2 or less. [Figure 30] 10 is a graph showing the relationship between the magnitude of the bias and the number of protrusions having an area of 100 nm 2 or more and 1000 nm 2 or less. [Figure 31] 10 is a graph showing the relationship between the magnitude of the bias and the number of protrusions having an area of 1000 nm 2 or more and 10000 nm 2 or less. [Figure 32] 10 is a graph showing the relationship between the magnitude of bias and the number of protrusions. [Figure 33] 1 is a photomicrograph showing the surface of a substrate when the hydrogen supply rate is 100 sccm and the bias is −25 V. [Figure 34] 34 is a micrograph showing carbon nanowalls grown on the substrate of FIG. 33. [Figure 35] 1 is a photomicrograph showing the surface of a substrate when the hydrogen supply rate is 100 sccm and the bias is −100 V. [Figure 36] 36 is a micrograph showing carbon nanowalls grown on the substrate of FIG. 35. DETAILED DESCRIPTION OF THE INVENTION

[0011] Specific embodiments will be described below with reference to the drawings, taking as examples a metal substrate for carbon nanowall growth, a metal substrate with carbon nanowalls, and a method for manufacturing these. In this specification, the term "electricity storage device" refers to a device that can be charged and discharged. Electricity storage devices include lithium ion primary batteries, lithium ion secondary batteries, lithium ion capacitors, and other devices that charge and discharge using lithium ions.

[0012] (First embodiment) 1. Lithium-ion secondary battery 1 is a schematic configuration diagram of a lithium ion secondary battery LiB1 of Embodiment 1. The lithium ion secondary battery LiB1 has a positive electrode PE, a negative electrode NE, a separator Sp1, an electrolytic solution ES1, and a container V1.

[0013] The positive electrode PE is the positive electrode of the lithium-ion secondary battery LiB1. The positive electrode PE has a positive electrode current collector P1 and a positive electrode active material layer P2. The positive electrode active material layer P2 is formed on the first surface P1a and the second surface P1b of the positive electrode current collector P1.

[0014] The positive electrode current collector P1 is a metal substrate. The positive electrode current collector P1 is, for example, a metal foil. The positive electrode current collector P1 may have other shapes. The material of the positive electrode current collector P1 is, for example, Al or Ti. The material of the positive electrode current collector P1 may also be a conductor such as another metal.

[0015] The positive electrode active material layer P2 contains a positive electrode active material, a conductive additive, and a binder. The positive electrode active material layer P2 may also contain a thickener. Examples of positive electrode active materials include lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, and ternary materials. Examples of conductive additives include carbon black. Examples of binders include SBR. Examples of thickeners include carboxymethyl cellulose. Thus, the positive electrode active material layer P2 contains lithium atoms.

[0016] The negative electrode NE is a negative electrode of a lithium-ion secondary battery LiB1. The negative electrode NE has a negative electrode current collector N1 and a negative electrode active material layer N2. The negative electrode active material layer N2 is formed on the first surface N1a and the second surface N1b of the negative electrode current collector N1. The negative electrode NE is a carbon nanowall body on which carbon nanowalls CNW1 are formed.

[0017] The negative electrode current collector N1 is a metal substrate for growing carbon nanowalls. The negative electrode current collector N1 is a metal substrate. The negative electrode current collector N1 is, for example, a metal foil. The negative electrode current collector N1 may have other shapes. The material of the negative electrode current collector N1 is, for example, Cu. The negative electrode current collector N1 is, for example, a copper plate or copper foil. The material of the negative electrode current collector N1 may be a conductor such as aluminum, titanium, or other metals.

[0018] The negative electrode active material layer N2 contains a negative electrode active material. The negative electrode active material layer N2 contains carbon nanowalls CNW1 as the negative electrode active material. The carbon nanowalls CNW1 will be described later.

[0019] The separator Sp1 serves to electrically insulate the positive electrode PE from the negative electrode NE, and is permeable to lithium ions in the electrolyte solution ES1.

[0020] The electrolyte ES1 has the property of transferring lithium ions between the positive electrode PE and the negative electrode NE. The electrolyte ES1 fills the container V1. The electrolyte ES1 is a liquid obtained by dissolving a lithium salt such as lithium hexafluorophosphate (LiPF6) in dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), or the like.

[0021] The container V1 accommodates the positive electrode PE, the negative electrode NE, the separator Sp1, and the electrolyte solution ES1 inside. The container V1 is made of a material that is less reactive with the electrolyte solution ES1.

[0022] 2.Protrusion FIG. 2 is a diagram schematically illustrating a cross section of a carbon nanowall CNW1 of a lithium-ion secondary battery LiB1 according to the first embodiment. The negative electrode current collector N1 is a metal substrate for growing the carbon nanowalls. The negative electrode current collector N1 has a first surface N1a. The first surface N1a is one surface of the negative electrode current collector N1. A plurality of protrusions PR1 are formed on the first surface N1a of the negative electrode current collector N1.

[0023] The protrusion PR1 is a portion of the negative electrode current collector N1 that partially protrudes from the first surface N1a. The protrusion PR1 may be composed of a single particle GR1 or a plurality of particles GR1. In this case, the material of the particle GR1 is preferably the same as the material of the negative electrode current collector N1. The particle GR1 is preferably fused to the first surface N1a of the negative electrode current collector N1 and integrated with the negative electrode current collector N1. This is to increase the adhesion between the negative electrode current collector N1 and the particle GR1 and prevent the particle GR1 from peeling off from the negative electrode current collector N1.

[0024] The planar size of the protrusion PR1 is measured by observing the surface of the negative electrode current collector N1 using a scanning electron microscope from a direction perpendicular to the first surface N1a. The area of the projection region of the protrusion PR1 projected onto the first surface N1a is 10 nm 2 More than 10000nm 2 Preferably, it is 20 nm or less. 2 More than 5000nm 2 The following is the result.

[0025] The protrusion PR1 is, for example, 10 μm from the first surface N1a of the negative electrode current collector N1. 2 In other words, the density of the projection area of the protrusion PR1 projected onto the first surface N1a is 1 particle / μm 2 More than 1000 pieces / μm 2 Preferably, it is 2 particles / μm or less. 2 More than 800 pieces / μm 2 More preferably, it is 3 particles / μm or less. 2 More than 500 pieces / μm 2 The following is the result.

[0026] As will be described later, when the protrusions PR1 are formed by irradiation with hydrogen plasma, it is believed that the protrusions PR1 are formed as follows: Copper particles GR1 are knocked out from the first surface N1a of the negative electrode current collector N1, and the knocked-out particles GR1 re-adhere to the first surface N1a of the negative electrode current collector N1 and fuse with the first surface N1a of the negative electrode current collector N1, thereby forming the protrusions PR1. Note that the size and density of the protrusions PR1 are believed to be important factors that determine the growth density of the carbon nanowalls CNW1.

[0027] The protrusions PR1 serve as starting points for the growth of the carbon nanowalls CNW1, and therefore the carbon nanowalls CNW1 are formed on the first surface N1a of the negative electrode current collector N1 so as to straddle the protrusions PR1.

[0028] 3. Carbon nanowalls 3-1.Structure of carbon nanowalls In this specification, a carbon nanowall is a conductive nanostructure composed mainly of carbon atoms arranged in a wall shape on a substrate such as the negative electrode current collector N1.

[0029] FIG. 3 is a diagram conceptually illustrating the structure of the carbon nanowall CNW1 of the lithium-ion secondary battery LiB1 of the first embodiment. FIG. 3 conceptually illustrates one graphene sheet GS1. The carbon nanowall CNW1 is electrically conductive. The carbon nanowall CNW1 may be composed of multiple graphene sheets GS1. The graphene sheet GS1 may not have a complete graphene structure, but may be a thin film mainly composed of carbon with a six-membered ring structure. The graphene sheet GS1 may have a mosaic structure mainly composed of carbon with a six-membered ring structure. A mosaic structure is a structure in which multiple regions having a six-membered ring structure are discretely arranged. In other words, the carbon nanowall CNW1 does not have to be entirely single-crystal six-membered rings.

[0030] The negative electrode NE includes a negative electrode current collector N1 and a negative electrode active material layer N2. The negative electrode active material layer N2 includes carbon nanowalls CNW1.

[0031] The carbon nanowall CNW1 is a graphite-like material in which about 10 layers of graphene sheets GS1 are stacked in the thickness direction of the carbon nanowall CNW1. The number of layers may be other than the above. Because the carbon nanowall CNW1 is a graphite-like material, the carbon nanowall CNW1 has a higher electrical conductivity than carbon materials such as activated carbon.

[0032] The carbon nanowall CNW1 has a root portion R1 on the side of the negative electrode current collector N1 and a tip portion E1 on the side opposite the negative electrode current collector N1. The root portion R1 is often a fixed portion that is fixed to the negative electrode current collector N1 via a protrusion PR1. The root portion R1 is also a connecting portion that is electrically connected to the negative electrode current collector N1.

[0033] In the carbon nanowall CNW1, the graphene sheet GS1 is formed in a direction intersecting the surfaces (first surface N1a and second surface N1b) of the negative electrode current collector N1. In FIG. 3, the graphene sheet GS1 and the negative electrode current collector N1 are approximately perpendicular to each other. Note that the carbon nanowall CNW1 does not have to be perpendicular to the negative electrode current collector N1. Even in this case, the carbon nanowall CNW1 functions as the negative electrode NE of the lithium ion secondary battery LiB1.

[0034] As mentioned above, the carbon nanowall CNW1 is a graphite layer consisting of many stacked graphene sheets GS1. In reality, the graphene sheets GS1 do not extend completely parallel to each other. Because the graphene sheets GS1 grow in different directions at each initial growth nucleus, the graphene sheets GS1 actually merge and overlap at random (see Figure 6). As shown in Figure 3, the distance between adjacent wall-like graphite particles is referred to as the wall spacing D1.

[0035] The average wall spacing, which is the average value of this wall spacing D1, is related to the density of the carbon nanowalls CNW1. In other words, the wider the average wall spacing, the lower the density of the carbon nanowalls CNW1. Conversely, the narrower the average wall spacing, the higher the density of the carbon nanowalls CNW1.

[0036] 3-2. Carbon nanowall height The average height H1 of the carbon nanowalls CNW1 is preferably 50 nm or more. Alternatively, the average height H1 of the carbon nanowalls CNW1 may be 200 nm or more. If the average height H1 of the carbon nanowalls CNW1 is 100 nm or more, lithium tends to deposit starting from the carbon nanowalls CNW1. The higher the average height H1, the longer the growth time. In other words, the higher the manufacturing cost. Therefore, for example, the average height H1 is 1 μm or more and 10 μm or less.

[0037] The average thickness W1 of the carbon nanowalls CNW1 is, for example, 0.5 nm or more and 100 nm or less, preferably 1 nm or more and 50 nm or less, and more preferably 1.5 nm or more and 30 nm or less.

[0038] The layer spacing of graphite is approximately 0.35 nm. Therefore, the thickness of the carbon nanowall CNW1, which is composed of 10 layers of graphene sheets GS1, is approximately 3.5 nm. Although it depends on the manufacturing conditions, the average thickness of the carbon nanowall CNW1 is approximately 3.5 nm, and it is thought to be composed of 5 to 20 layers of graphene sheets GS1. The thickness of the carbon nanowall CNW1 is, for example, 1.5 nm or more and 7 nm or less.

[0039] 3-3.Wall spacing The average wall spacing D1 between adjacent carbon nanowalls CNW1 is, for example, 10 nm or more and 500 nm or less. Preferably, it is 15 nm or more and 100 nm or less. More preferably, it is 20 nm or more and 50 nm or less. These numerical ranges are examples, and other numerical values may be used. Note that the long walls of the carbon nanowalls do not necessarily grow in parallel, and the walls may merge with each other (see FIG. 6). Therefore, the spacing between the carbon nanowalls CNW1 near this merging point is narrower than the spacing between the carbon nanowalls CNW1 at other points.

[0040] In order to grow the carbon nanowalls CNW1 having a wall spacing D1 of 15 nm or more and 100 nm or less, the area of the protrusions PR1, which are the starting points of the growth of the carbon nanowalls CNW1, projected onto the first surface N1a is set to 20 nm or less. 2 More than 5000nm 2 The density of the protrusions PR1 is preferably 3 / μm or less. 2 More than 2500 pieces / μm 2It is preferable that the diameter is less than 10 nm. Modeling can be done as follows: To grow a carbon nanowall CNW1 with a wall spacing D1 of 20 nm, one protrusion PR1 is present at a lattice point spaced 20 nm apart, and the carbon nanowall CNW1 grows starting from PR1 at that lattice point. In this case, assuming that the protrusion is hemispherical, the diameter is preferably about 10 nm, and the area of the protrusion PR1 projected onto the first surface N1a is about 80 nm. 2 The density of the protrusions PR1 is 2500 / μm 2 Similarly, to grow a carbon nanowall CNW1 having a wall spacing D1 of 50 nm, the area of the protrusion PR1 projected onto the first surface N1a must be approximately 500 nm 2 The density of the protrusions PR1 is 400 / μm 2 In order to grow carbon nanowalls CNW1 with a wall spacing D1 of 100 nm, the area of the protrusions PR1 projected onto the first surface N1a is approximately 2000 nm 2 The density of the protrusions PR1 is 100 / μm 2 That is, in order to grow the carbon nanowalls CNW1 with a wall spacing D1 of 20 nm or more and 100 nm or less, the area of the protrusions PR1, which are the starting points of the growth of the carbon nanowalls CNW1, projected onto the first surface N1a is 80 nm 2 More than 2000nm 2 The density of the protrusions PR1 is preferably 100 / μm 2 More than 2500 pieces / μm 2 In reality, it is not necessary for the protrusions PR1 to exist at all of the lattice points, and it is considered that protrusions PR1 may be present at a lower density.

[0041] 4. Charge and discharge reactions involving lithium ions 4-1.Charge and discharge reaction The negative electrode NE has carbon nanowalls CNW1, which can cause two or more lithium ions per carbon atom to participate in a charge / discharge reaction during one charge or discharge.

[0042] Here, the charge / discharge reaction is, for example, a chemical reaction expressed by the following chemical reaction formula. Li + + e - ⇔ Li …(1) Li1-xCoO2 + xLi + + xe - ⇔ LiCoO2 …(2) Equation (1) represents the reaction in the negative electrode active material layer N2. Equation (2) represents the reaction in the positive electrode active material layer P2. Both reactions involve lithium ions and electrons. A charge / discharge reaction is a chemical reaction in the positive electrode PE or negative electrode NE in which lithium ions are involved and electrons are exchanged. This charge / discharge reaction can result in the absorption or release of lithium ions, as well as the precipitation, deposition, adsorption, or dissolution of lithium or lithium compounds. If lithium or lithium compounds are precipitated, the charge / discharge reaction can occur outside the positive electrode active material layer P2 or negative electrode active material layer N2. The type of charge / discharge reaction varies depending on the materials used for the positive electrode active material layer P2 and negative electrode active material layer N2.

[0043] 5. Manufacturing equipment A manufacturing apparatus for forming carbon nanowalls CNW1 on the first surface N1a of the negative electrode current collector N1 will be described.

[0044] 4 is a schematic diagram showing the configuration of a manufacturing apparatus 1 for growing carbon nanowalls CNW1 in a lithium-ion secondary battery LiB1 according to the first embodiment. The manufacturing apparatus 1 has a plasma generation chamber 46 and a reaction chamber 10. The plasma generation chamber 46 is used to generate plasma therein and also to generate radicals to be supplied to the reaction chamber 10. The reaction chamber 10 is used to form carbon nanowalls CNW1 by utilizing the radicals generated in the plasma generation chamber 46.

[0045] The manufacturing apparatus 1 also has a waveguide 47, a quartz window 48, and a slot antenna 49. The waveguide 47 is for introducing the microwaves 39. The slot antenna 49 is for introducing the microwaves 39 from the quartz window 48 into the plasma generation chamber 46.

[0046] The plasma generation chamber 46 is for generating surface wave plasma (SWP) by microwaves 39. The plasma generation chamber 46 is provided with a radical source inlet 42. The radical source inlet 42 is for supplying a gas that serves as a radical source into the inside of the plasma 61 generated in the plasma generation chamber 46.

[0047] A partition wall 44 is provided between the plasma generation chamber 46 and the reaction chamber 10. The partition wall 44 separates the plasma generation chamber 46 from the reaction chamber 10. The partition wall 44 also serves as a first electrode 22 for applying a voltage. A through-hole 14 is formed in the partition wall 44. This is for supplying radicals generated in the plasma generation chamber 46 to the reaction chamber 10.

[0048] The reaction chamber 10 is used to generate capacitively coupled plasma (CCP). The reaction chamber 10 is also used to form carbon nanowalls CNW1 on the negative electrode current collector N1. The reaction chamber 10 has a second electrode 24, a heater 25, a raw material inlet 12, and an exhaust port 16. The second electrode 24 is used to apply a voltage between the first electrode 22 and the second electrode 24. The heater 25 is used to heat the negative electrode current collector N1 and control the temperature of the negative electrode current collector N1. The raw material inlet 12 is used to supply a carbon-based gas 32, which is a raw material for the carbon nanowalls. The exhaust port 16 is connected to a vacuum pump or the like. The vacuum pump is used to adjust the pressure inside the reaction chamber 10.

[0049] As described above, the partition wall 44 also serves as the first electrode 22 for applying a voltage between it and the second electrode 24. A power source and a circuit are connected to the first electrode 22 in order to control the potential of the first electrode 22 over time. The second electrode 24 is used to apply a voltage between it and the first electrode 22. The second electrode 24 also serves as a mounting base for placing the negative electrode current collector N1 thereon. The second electrode 24 is grounded. The distance between the first electrode 22 and the second electrode 24 is approximately 5 cm. Of course, this value is not limiting.

[0050] 6. Negative electrode manufacturing method 6-1. Protrusion formation process First, the negative electrode current collector N1 before the carbon nanowalls CNW1 are formed is placed inside the manufacturing apparatus 1. At this time, the first surface N1a of the negative electrode current collector N1 faces up, and the second surface N1b is in contact with the second electrode 24. Next, microwaves 39 are introduced into the waveguide 47. The microwaves 39 are introduced into the plasma generation chamber 46 through the quartz window 48 by the slot antenna 49. This generates high-density plasma 60.

[0051] This high-density plasma 60 then diffuses inside the plasma generation chamber 46 to become plasma 61. This plasma 61 contains ions of the radical source supplied from the radical source inlet 42. A gas containing hydrogen gas is used as the radical source. Most of the ions in the plasma 61 are attracted to and collide with the partition wall 44. The radicals 38 in the plasma 61 pass through the through-holes 14 in the partition wall 44 without being attracted to the partition wall 44, and enter the reaction chamber 10. Then, a voltage is applied between the first electrode 22 and the second electrode 24. This generates plasma 34 inside the reaction chamber 10.

[0052] Radicals 38 are present in the atmosphere of the plasma 34. Then, protrusions PR1 grow on the first surface N1a of the negative electrode current collector N1 in the atmosphere of this plasma 34. At that time, copper particles GR1 are scattered from the first surface N1a of the negative electrode current collector N1 and re-adhere to the first surface N1a of the negative electrode current collector N1.

[0053] The pressure inside the reaction chamber 10 is within a range of 5 to 2000 mTorr (0.65 Pa to 267 Pa). The temperature of the negative electrode current collector N1 is within a range of 0°C or higher and lower than 500°C, and preferably 0°C or higher and 400°C or lower. Of course, these are merely examples, and the present invention is not limited to these numerical ranges.

[0054] 6-2. Carbon nanowall growth process Next, carbon nanowalls CNW1 are grown on the protrusions PR1 inside the manufacturing apparatus 1. In the same manner as when growing the protrusions PR1, plasma 61 is generated. In addition to radicals 38, a carbon-based gas 32 is supplied from the raw material inlet 12 into the reaction chamber 10. Hydrogen gas is used as the radical source for the radicals 38, and, for example, CH4 or C2F6 is used as the carbon-based gas 32. Of course, other gases may also be used. Furthermore, a rare gas such as Ar may be added to these gases.

[0055] In this manner, a gas containing carbon atoms is converted into plasma and supplied to the negative electrode current collector N1 inside the manufacturing apparatus 1. Carbon nanowalls are grown on the protrusions PR1 on the first surface N1a of the negative electrode current collector N1, with the protrusions PR1 serving as growth starting points.

[0056] The pressure inside the reaction chamber 10 is within a range of 5 to 2000 mTorr (0.65 Pa to 267 Pa). The temperature of the negative electrode current collector N1 is within a range of 0° C. to 500° C. Of course, these are merely examples and the present invention is not limited to these numerical ranges.

[0057] In this way, in the first embodiment, a gas containing hydrogen is converted into plasma and supplied to a metal substrate, and protrusions are formed on a first surface of the metal substrate by fusing a plurality of particles made of the same material as the metal substrate with the first surface.A gas containing carbon atoms is converted into plasma and supplied to the metal substrate, and carbon nanowalls are grown on the protrusions on the first surface of the metal substrate.

[0058] 8. Effects of the First Embodiment The negative electrode NE of the lithium-ion secondary battery LiB1 of the first embodiment has protrusions PR1. The protrusions PR1 are aggregates of a plurality of particles GR1 fused to the first surface N1a of the negative electrode current collector N1. Therefore, carbon nanowalls CNW1 are likely to be generated starting from the protrusions PR1. Therefore, the film formation temperature of the carbon nanowalls CNW1 is 0°C or higher and 500°C or lower, which is lower than the conventional film formation temperature.

[0059] 9. Variations 9-1.Amorphous carbon layer The negative electrode NE may have an amorphous carbon layer AC1. The amorphous carbon layer AC1 is electrically conductive. The amorphous carbon layer AC1 is located between the first surface N1a of the negative electrode current collector N1 and the carbon nanowall CNW1. The amorphous carbon layer AC1 can be a layer that can serve as a starting point for the growth of the graphene sheet GS1 that constitutes the carbon nanowall CNW1. The film thickness of the amorphous carbon layer AC1 is, for example, 10 nm or more and 300 nm or less, preferably 10 nm or more and 100 nm or less, and more preferably 12 nm or more and 30 nm or less.

[0060] 9-2. Manufacturing equipment In the first embodiment, the protrusion forming step and the carbon nanowall growing step are performed consecutively inside the manufacturing apparatus 1. However, the protrusion forming step and the carbon nanowall growing step may be performed in separate apparatuses. Also, a film forming apparatus using plasma other than the manufacturing apparatus 1 may be used.

[0061] 9-3. Protrusion formation process Other treatments may be performed as the protrusion forming step, such as pressure treatment using a press or the like, chemical treatment, sputtering using a copper or aluminum target, and the like.

[0062] 9-4.Metal substrate The metal substrate preferably contains at least one of copper and aluminum. For example, the metal substrate may contain copper, a copper alloy, aluminum, or an aluminum alloy. The metal substrate may be in the form of a plate, foil, or other shape.

[0063] 9-5. Combinations The above modifications may be freely combined. [Example]

[0064] (experiment) 1. Formation of protrusions A protrusion PR1 was formed on a copper foil (copper substrate) inside the manufacturing apparatus 1. The conditions are shown in Table 1. The flow rate of hydrogen gas was 50 sccm. The flow rate of Ar was 5 sccm. The microwave power (MW power) was 400 W. The power applied between the electrodes (CCP power) was 400 W. The temperature of the heater 25 was 560°C. The processing time was 10 minutes.

[0065] Note that the carbon-based gas 32 that is the raw material gas for the carbon nanowalls CNW1 is not supplied to the inside of the manufacturing apparatus 1. Therefore, plasma of hydrogen gas is generated, and hydrogen radicals are supplied to the copper foil.

[0066] [Table 1] Conditions Protrusion formation process H2 (sccm) 50 Ar(sccm) 5 MW power (W) 400 CCP power (W) 400 Pressure (Pa) 2 Heater temperature (℃) 560 Processing time (min) 10

[0067] Figure 5 is a scanning electron microscope photograph (part 1) showing the surface of copper foil after it has been irradiated with hydrogen radicals. Figure 5 shows that numerous copper particles have accumulated on the surface of the copper foil, forming protrusions. Judging from the shape of the particles observed, it is believed that the copper particles were knocked out of the copper foil by the irradiation of hydrogen radicals and then re-adhered to the surface of the copper foil.

[0068] 2. Formation of protrusions and carbon nanowalls 2-1. Film formation Protrusions PR1 and carbon nanowalls CNW1 were formed on a copper foil (copper substrate) inside the manufacturing apparatus 1. The conditions are shown in Table 2. When growing the protrusions PR1 and the carbon nanowalls CNW1, the temperature of the heater 25 was changed between room temperature (RT) and 500°C.

[0069] [Table 2] Conditions Protrusion formation process CNW growth process CH4 (sccm) 0 100 H2 (sccm) 50 50 Ar(sccm) 5 5 MW power (W) 400 400 CCP power (W) 400 400 Pressure (Pa) 2 1 Heater temperature (℃) 20-500 20-500 Processing time (min) 10 10

[0070] 2-2.Photo of carbon nanowalls Figure 6 is a scanning electron microscope photograph showing the surface of carbon nanowalls grown at a heater temperature of 500°C. The substrate temperature is determined by the heater temperature setting and the energy imparted to the substrate by the plasma. Although the substrate temperature may be higher than the heater temperature setting due to particles from the plasma colliding with the substrate, these temperatures are estimated to be roughly the same. As shown in Figure 6, the carbon nanowalls grow randomly, with the walls merging with each other.

[0071] Figure 7 is a scanning electron microscope photograph showing the cross section of carbon nanowalls grown at a heater temperature of 500° C. As shown in Figure 7, carbon nanowalls with a height of 1 μm were grown after 10 minutes of film formation.

[0072] Figure 8 is a scanning electron microscope photograph showing the surface of carbon nanowalls grown at a heater temperature of 400° C. As shown in Figure 8, the carbon nanowalls grow randomly and merge with each other.

[0073] Figure 9 is a scanning electron microscope photograph showing the cross section of carbon nanowalls grown at a heater set temperature of 400° C. As shown in Figure 9, carbon nanowalls with a height of 900 nm were grown after 10 minutes of film formation.

[0074] Figure 10 is a scanning electron microscope photograph showing the surface of carbon nanowalls grown at a heater temperature of 300° C. As shown in Figure 10, the carbon nanowalls grow randomly and merge with each other.

[0075] Figure 11 is a scanning electron microscope photograph showing the cross section of carbon nanowalls grown at a heater temperature of 300° C. As shown in Figure 11, carbon nanowalls with a height of 850 nm were grown after 10 minutes of film formation.

[0076] Figure 12 is a scanning electron microscope photograph showing the surface of carbon nanowalls grown at a heater temperature of 200° C. As shown in Figure 12, the carbon nanowalls grow randomly and merge with each other.

[0077] Figure 13 is a scanning electron microscope photograph showing the cross section of carbon nanowalls grown at a heater temperature of 200° C. As shown in Figure 13, carbon nanowalls with a height of 750 nm were grown after 10 minutes of film formation.

[0078] Figure 14 is a scanning electron microscope photograph showing the surface of carbon nanowalls grown at a heater temperature of 20° C. As shown in Figure 14, the carbon nanowalls grow randomly and merge with each other.

[0079] Figure 15 is a scanning electron microscope photograph showing the cross section of carbon nanowalls grown at a heater temperature of 20° C. As shown in Figure 15, carbon nanowalls with a height of 800 nm were grown after 10 minutes of film formation.

[0080] Figure 16 is a scanning electron microscope photograph showing the surface of carbon nanowalls grown at a heater setting temperature of 500°C without irradiating with hydrogen radicals. In this case, protrusions PR1 are not formed. As shown in Figure 16, carbon nanowalls grow slightly even without irradiating with hydrogen radicals. However, the density of the carbon nanowalls is sparse. Therefore, the density of these carbon nanowalls is insufficient for use in the negative electrode of a lithium-ion secondary battery.

[0081] 2-3. Lithium-ion secondary battery A lithium-ion secondary battery LiB1 of the first embodiment was manufactured. The positive electrode current collector P1 was aluminum, and the positive electrode active material was lithium cobalt oxide. The negative electrode current collector N1 was copper, and the negative electrode active material was carbon nanowalls. The electrolyte was 1M LiPF6. The positive electrode active material layer had a diameter of 1.6 cm. The negative electrode active material layer had a diameter of 1.3 cm.

[0082] The positive electrode active material layer contained lithium cobalt oxide, a conductive additive, and a binder. The conductive additive was acetylene black. The binder was PVDF. The weight ratio of the lithium cobalt oxide, acetylene black, and PVDF was 100:5:3.

[0083] FIG. 17 is a graph showing the relationship between the capacity and voltage of a lithium-ion secondary battery having a negative electrode in which carbon nanowalls were grown on copper foil at a heater setting temperature of 500°C. The horizontal axis of FIG. 17 represents charge / discharge capacity. The vertical axis of FIG. 17 represents voltage. The charge or discharge current was 0.5 mA. As shown in FIG. 17, the discharge capacity of the lithium-ion secondary battery was 13.1 mAh.

[0084] FIG. 18 is a graph showing the relationship between the capacity and voltage of a lithium-ion secondary battery having a negative electrode in which carbon nanowalls were grown on copper foil at a heater setting temperature of 400°C. The horizontal axis of FIG. 18 represents charge / discharge capacity. The vertical axis of FIG. 18 represents voltage. The charge or discharge current was 0.5 mA. As shown in FIG. 18, the discharge capacity of the lithium-ion secondary battery was 13.1 mAh.

[0085] FIG. 19 is a graph showing the relationship between the capacity and voltage of a lithium-ion secondary battery having a negative electrode in which carbon nanowalls were grown on copper foil with a heater set temperature of 300°C. The horizontal axis of FIG. 19 represents charge / discharge capacity. The vertical axis of FIG. 19 represents voltage. The charge or discharge current was 0.5 mA. As shown in FIG. 19, the discharge capacity of the lithium-ion secondary battery was 13.1 mAh.

[0086] FIG. 20 is a graph showing the relationship between the capacity and voltage of a lithium-ion secondary battery having a negative electrode in which carbon nanowalls were grown on copper foil with a heater set temperature of 200°C. The horizontal axis of FIG. 20 represents charge / discharge capacity. The vertical axis of FIG. 20 represents voltage. The charge or discharge current was 0.5 mA. As shown in FIG. 20, the discharge capacity of the lithium-ion secondary battery was 12.8 mAh.

[0087] FIG. 21 is a graph showing the relationship between the capacity and voltage of a lithium-ion secondary battery having a negative electrode in which carbon nanowalls were grown on copper foil with a heater set temperature of 20°C. The horizontal axis of FIG. 21 represents charge / discharge capacity. The vertical axis of FIG. 21 represents voltage. The charge or discharge current was 0.5 mA. As shown in FIG. 21, the discharge capacity of the lithium-ion secondary battery was 13.1 mAh.

[0088] 3. Particles 3-1.Plasma equipment In this experiment, the protrusion forming step was carried out using an inductively coupled plasma (ICP) device instead of the manufacturing device 1. Table 3 shows the processing conditions in the ICP device.

[0089] [Table 3] Conditions Protrusion formation process H2 (sccm) 100 Ar(sccm) 15 ICP power (W) 1000 Pressure (Pa) 3 Heater temperature (℃) 560 Processing time (min) 10

[0090] 3-2. Hydrogen gas supply amount and protrusions The amount of hydrogen gas supplied was changed to examine the number and size of the protrusions. The bias applied to the second electrode 24 was 0V.

[0091] FIG. 22 is a scanning electron microscope photograph (part 2) showing the surface of a copper foil after irradiating the copper foil with hydrogen radicals.

[0092] Figure 23 is a scanning electron microscope photograph (part 3) showing the surface of copper foil after irradiating it with hydrogen radicals. Figure 23 is an enlarged photograph of a part of Figure 22. The white areas are the protrusions.

[0093] Figure 24 is a graph showing the measurement results of the unevenness on the line in Figure 23. The horizontal axis in Figure 24 is position. The vertical axis in Figure 24 is height from the reference plane. As shown in Figure 24, protrusions with a height of about 200 nm and a width of about 200 nm were observed. As can be inferred from Figure 24, the height and width of the protrusions are approximately the same.

[0094] The area of the white region in the scanning electron microscope was measured using the scanning electron microscope function. The area of the white region corresponds to the two-dimensional size of the protrusion.

[0095] Figure 25 shows the relationship between the amount of hydrogen supplied and the area of the protrusions when the protrusion area is 10 nm 2 More than 100nm 2 The horizontal axis of FIG. 25 is the hydrogen supply amount (sccm). The vertical axis of FIG. 25 is the 10 μm 2 When the hydrogen supply rate is 100 sccm, the area is 10 nm2 More than 100nm 2 There tends to be a large number of small protrusions such as those shown below.

[0096] Figure 26 shows the relationship between the amount of hydrogen supplied and the area of the protrusions when the protrusion area is 100 nm 2 More than 1000nm 2 The horizontal axis of FIG. 26 is the hydrogen supply amount (sccm). The vertical axis of FIG. 26 is the 10 μm 2 When the hydrogen supply rate is 50 sccm, the area is 100 nm 2 More than 1000nm 2 There tends to be a high number of medium-sized protrusions below.

[0097] Figure 27 shows the relationship between the amount of hydrogen supplied and the area of the protrusions when the protrusion area is 1000 nm 2 More than 10000nm 2 The horizontal axis of FIG. 27 is the hydrogen supply amount (sccm). The vertical axis of FIG. 27 is the 10 μm 2 When the hydrogen supply rate is 100 sccm, the area is 1000 nm 2 More than 10000nm 2 There tends to be a large number of large protrusions such as those below.

[0098] 28 is a graph showing the relationship between the amount of hydrogen supplied and the number of protrusions. The horizontal axis of FIG. 28 is the amount of hydrogen supplied (sccm). The vertical axis of FIG. 28 is 10 μm. 2 The number of protrusions tends to be higher when the hydrogen supply rate is 100 sccm.

[0099] As described above, when the hydrogen supply rate is 100 sccm, the number of protrusions tends to be large. In this case, the number of small protrusions and the number of large protrusions are large.

[0100] When the hydrogen supply rate is 50 sccm, the area is 100 nm 2 More than 1000nm 2There tends to be a large number of medium-sized protrusions below this size. At this time, the number of large and small protrusions is not so large. Therefore, in this case, the protrusions are uniform in size to a medium level.

[0101] 3-3. Bias and protrusions The supply amount of hydrogen was set to 100 sccm, and the bias applied to the second electrode 24 was varied. The bias applied to the second electrode 24 was a DC bias.

[0102] Figure 29 shows the relationship between the bias size and the area of the protrusion, which is 10 nm. 2 More than 100nm 2 The horizontal axis of FIG. 29 is bias. The vertical axis of FIG. 29 is 10 μm. 2 As shown in Figure 29, by applying a negative bias, the area of the protrusions was reduced to 10 nm 2 More than 100nm 2 The number of protrusions below decreases.

[0103] Figure 30 shows the relationship between the bias size and the area of the protrusion, which is 100 nm 2 More than 1000nm 2 30 is a graph showing the relationship between the number of protrusions and the horizontal axis of FIG. 30 is bias. The vertical axis of FIG. 30 is 10 μm. 2 As shown in Figure 30, when a bias of -25V was applied, the area of the protrusions was 100 nm 2 More than 1000nm 2 The number of protrusions below 100 nm is the largest. 2 More than 1000nm 2 When forming a substrate having a large number of protrusions as described below, it is preferable to apply a bias of about -25V.

[0104] Figure 31 shows the relationship between the bias magnitude and the area of the protrusion, 1000 nm 2 More than 10000nm 2 31 is a graph showing the relationship between the number of protrusions and the horizontal axis of FIG. 31 is bias. The vertical axis of FIG. 31 is 10 μm. 2As shown in Figure 31, when a bias of -50 V was applied, the area of the protrusions was 1000 nm 2 More than 10000nm 2 The number of protrusions below this is the largest. 2 More than 10000nm 2 When forming a substrate having a large number of protrusions as described below, it is preferable to apply a bias of about -50V.

[0105] Figure 32 is a graph showing the relationship between the magnitude of the bias and the number of protrusions. The horizontal axis of Figure 32 is the bias. The vertical axis of Figure 32 is 10 μm. 2 When a negative bias is applied, the number of protrusions tends to decrease as the absolute value of the bias increases.

[0106] When the bias is 0V, the area is 10nm 2 More than 100nm 2 When the bias is -25V, the number of small protrusions with an area of 100nm or less tends to be large. 2 More than 1000nm 2 When the bias is -50V, the number of medium-sized protrusions below 1000nm tends to be large. 2 More than 10000nm 2 There is a tendency for the number of large protrusions as follows to be large. When the bias is -100V, protrusions tend to be less likely to be formed regardless of their size.

[0107] The larger the absolute value of the negative bias, the more easily the hydrogen ions collide with the substrate, and the higher the kinetic energy of the hydrogen ions.

[0108] In this way, by selecting the amount of hydrogen supplied and the bias value, it is possible to control to some extent the size and number of protrusions formed on the substrate.

[0109] Figure 33 is a micrograph showing the surface of the substrate when the hydrogen supply rate is 100 sccm and the bias is -25 V. As shown in Figure 33, a relatively large number of protrusions are formed.

[0110] Figure 34 is a micrograph showing carbon nanowalls grown on the substrate of Figure 33. The carbon nanowalls have grown sufficiently and are merging with each other.

[0111] Figure 35 is a micrograph showing the surface of the substrate when the hydrogen supply rate is 100 sccm and the bias is -100 V. As shown in Figure 35, the protrusions are sparse and few in number.

[0112] Figure 36 is a micrograph showing carbon nanowalls grown on the substrate of Figure 35. The carbon nanowalls also grow sparsely and with wide spacing between them, meaning the density of the carbon nanowalls is low.

[0113] Therefore, when growing carbon nanowalls, the density of the carbon nanowalls tends to be higher when the number of protrusions is larger.

[0114] (Addendum) The metal substrate for growing carbon nanowalls in the first embodiment has a metal substrate having a first surface. The metal substrate has a plurality of protrusions on the first surface. The area of the projection region obtained by projecting the protrusions onto the first surface is 10 nm 2 More than 10000nm 2 The density of the protrusions is 1 / μm 2 More than 1000 pieces / μm 2 The following is the result.

[0115] In the second embodiment of the metal substrate for growing carbon nanowalls, the protrusions are made of the same material as the metal substrate and are fused with the first surface of the metal substrate to be integrated with the metal substrate.

[0116] The metal substrate for growing carbon nanowalls in the third embodiment contains at least one of copper and aluminum.

[0117] A fourth embodiment of the present invention provides a metal substrate with carbon nanowalls, which comprises a metal substrate having a first surface and carbon nanowalls formed on the first surface of the metal substrate. The metal substrate has a plurality of protrusions on the first surface. The area of the protrusions projected onto the first surface is 10 nm or less. 2 More than 10000nm 2 The density of the protrusions is 1 / μm 2 More than 1000 pieces / μm 2 The carbon nanowalls straddle the protrusions.

[0118] In the fifth embodiment of the metal substrate with carbon nanowalls, the protrusions are made of the same material as the metal substrate and are fused to the first surface of the metal substrate to form an integral part of the metal substrate.

[0119] In the sixth embodiment of the metal substrate with carbon nanowalls, the metal substrate is a copper plate or copper foil.

[0120] In the seventh embodiment, the metal substrate with carbon nanowalls has an amorphous carbon layer between the first surface of the metal substrate and the carbon nanowalls.

[0121] In the eighth aspect of the method for manufacturing a metal substrate for growing carbon nanowalls, a gas containing hydrogen gas is converted into plasma and supplied to the metal substrate, forming a plurality of protrusions made of the same material as the metal substrate on the first surface of the metal substrate.

[0122] In the ninth embodiment of the method for producing a metal substrate for growing carbon nanowalls, the protrusions are made of the same material as the metal substrate and are fused to the first surface of the metal substrate.

[0123] In the tenth embodiment of the method for producing a metal substrate for growing carbon nanowalls, the metal substrate is a copper plate or copper foil.

[0124] In the eleventh aspect of the method for producing a metal substrate with carbon nanowalls, a gas containing carbon atoms is converted into plasma and supplied to a metal substrate for growing carbon nanowalls, and carbon nanowalls are grown using the protrusions on the first surface of the metal substrate as growth starting points.

[0125] In the twelfth aspect of the method for producing a metal substrate with carbon nanowalls, a gas containing hydrogen gas is converted into plasma and supplied to the metal substrate, forming multiple protrusions made of the same material as the metal substrate on the first surface of the metal substrate, and a gas containing carbon atoms is converted into plasma and supplied to the metal substrate, causing carbon nanowalls to grow using the protrusions on the first surface of the metal substrate as growth starting points.

[0126] In the thirteenth embodiment of the method for producing a metal substrate with carbon nanowalls, the protrusions are made of the same material as the metal substrate and are fused to the first surface of the metal substrate.

[0127] In the fourteenth embodiment of the method for producing a metal substrate with carbon nanowalls, the metal substrate is a copper plate or copper foil.

[0128] In the fifteenth embodiment of the method for producing a metal substrate with carbon nanowalls, the temperature of the metal substrate when growing the carbon nanowalls is 0°C or higher and lower than 500°C. [Explanation of symbols]

[0129] LiB1...Lithium-ion secondary battery PE: Positive electrode P1…Positive electrode current collector P2...Positive electrode active material layer NE...negative electrode N1…Negative electrode current collector N1a…Side 1 PR1…Protrusion GR1…particle N2…Negative electrode active material layer CNW1...Carbon nanowall Sp1...Separator ES1…Electrolyte V1…Container E1…Tip R1: Base GS1...Graphene sheet

Claims

1. a metal substrate having a first surface; carbon nanowalls formed on the first surface of the metal substrate; and The metal substrate is a plurality of protrusions on the first surface; The area of a projected region obtained by projecting each of the protrusions onto the first surface is 10 nm ２ 10000nm or more ２ is as follows: The density of the protrusions is 1 piece / μm ２ More than 1000 pieces / μm ２ is as follows: The carbon nanowalls are The protrusion is straddled. A metal substrate with carbon nanowalls comprising:

2. The carbon nanowall-bearing metal substrate according to claim 1 , The protrusion is The material is the same as that of the metal substrate, The metal substrate is fused to the first surface thereof to be integral with the metal substrate. A metal substrate with carbon nanowalls comprising:

3. The carbon nanowall-bearing metal substrate according to claim 1 or 2, The metal substrate Copper plate or copper foil A metal substrate with carbon nanowalls comprising:

4. The metal substrate with carbon nanowalls according to any one of claims 1 to 3, an amorphous carbon layer is provided between the first surface of the metal substrate and the carbon nanowalls; A metal substrate with carbon nanowalls comprising:

5. A gas containing hydrogen gas is converted into plasma to supply hydrogen radicals to the metal substrate, forming a plurality of protrusions made of the same material as the metal substrate on a first surface of the metal substrate; A method for manufacturing a metal substrate, wherein each of the protrusions is composed of one or more particles.

6. The method for manufacturing a metal substrate according to claim 5, The protrusion is The material is the same as that of the metal substrate, The metal substrate is fused to the first surface. A method for manufacturing a metal substrate, comprising:

7. 7. The method for producing a metal substrate according to claim 5 or 6, The metal substrate Copper plate or copper foil A method for manufacturing a metal substrate, comprising:

8. A gas containing hydrogen gas is converted into plasma to supply hydrogen radicals to the metal substrate, forming a plurality of protrusions made of the same material as the metal substrate on a first surface of the metal substrate; a plasma of a gas containing carbon atoms is supplied to the metal substrate, and carbon nanowalls are grown from the protrusions on the first surface of the metal substrate as growth starting points; In the method for producing a metal substrate with carbon nanowalls, each of the protrusions is composed of one or more particles.

9. 9. The method for producing a metal substrate with carbon nanowalls according to claim 8, The area of a projected region obtained by projecting each of the protrusions onto the first surface is 10 nm ２ 10000nm or more ２ The density of the protrusions is 1 piece / μm or less. ２ More than 1000 pieces / μm ２ forming a plurality of said protrusions so that: A method for producing a metal substrate with carbon nanowalls, comprising:

10. 10. The method for producing a metal substrate with carbon nanowalls according to claim 9, The protrusion is The material is the same as that of the metal substrate, The metal substrate is fused to the first surface. A method for producing a metal substrate with carbon nanowalls, comprising:

11. 11. The method for producing a metal substrate with carbon nanowalls according to claim 8, wherein: The metal substrate contains at least one of copper and aluminum. A method for producing a metal substrate with carbon nanowalls, comprising:

12. The method for producing a metal substrate with carbon nanowalls according to claim 11, The metal substrate Copper plate or copper foil A method for producing a metal substrate with carbon nanowalls, comprising:

13. 13. The method for producing a metal substrate with carbon nanowalls according to claim 8, wherein: The temperature of the metal substrate during the growth of the carbon nanowalls is Between 0°C and 500°C A method for producing a metal substrate with carbon nanowalls, comprising:

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