JP6138007B2 - Conductive member, electrode, secondary battery, capacitor, and conductive member and electrode manufacturing method - Google Patents

Description

  The present invention generally includes a secondary battery, a conductive member such as a current collector constituting an electrode of a capacitor, an electrode provided with the conductive member, a secondary battery and a capacitor including the electrode, and a The present invention relates to a method for manufacturing a conductive member and an electrode. Specifically, the secondary battery is a secondary battery such as a lithium ion battery, and the capacitor is a lithium ion capacitor, an electric double layer capacitor, or a functional solid capacitor.

  In recent years, lithium ion batteries, electric double layer capacitors, and the like have been used as power sources for mobile phones, personal computers, digital cameras, and automobiles as highly energy efficient power storage devices. In the lithium ion secondary battery, as the positive electrode material, for example, a material obtained by coating the surface of a current collector made of an aluminum foil with an active material made of a lithium metal oxide salt, carbon fine particles, and a fluorine-based binder is used. Also in the electric double layer capacitor, in order to constitute an electrode, an active material made of carbon is coated on an aluminum foil as a current collector.

  Aluminum foil is not easily attacked by the electrolyte because a passive film made of aluminum oxide is formed on the surface of the aluminum foil. This passive film partially has voids (microdefects) and thus has electrical conductivity. Aluminum foil is a material with good processability and excellent economic efficiency. For these reasons, aluminum foil is used as a base material for current collectors of positive and negative electrodes of electric double layer capacitors and secondary batteries.

However, in a conventional secondary battery using an organic electrolytic solution containing an electrolyte composed of a fluorine-based anion such as LiBF ₄ , LiPF ₆ , (C ₂ H ₅ ) ₄ NBF _4, an electrolyte constituting a driving electrolytic solution when a voltage is applied F ^- components such as BF ₄ and PF ₆ used as anions react through aluminum as a positive electrode current collector and a passive film having voids, and aluminum is eluted. That is, the current collector is corroded. There was a problem that the electrode active material layer was easily peeled off due to corrosion of the current collector.

Electric double layer capacitors have been used in a wide variety of applications such as energy storage and power. In the case of energy storage, the energy density (Wh / L) is high, that is, a relatively thick electrode active material layer (polarizable electrode layer) is formed on the current collector, and the electrostatic capacity per unit volume Need to be increased. Further, as a power application, it is necessary to increase the power density (W / cm ² ). Furthermore, since the electric double layer capacitor has a rated voltage ranging from 2.5 V to 3.5 V, when the electric double layer capacitor is used as a power application, the internal resistance of the electric double layer capacitor is small, It is important that the loss is small. In particular, when the internal resistance is large, the value of IR-drop due to the internal resistance increases during discharging with a large current, and the power loss increases.

  The internal resistance of the electric double layer capacitor is composed of the specific resistance of the electrolyte, the specific resistance of the electrode active material layer, the contact resistance between the current collector and the electrode active material layer, and the resistance of the current collector itself. In the case of a conventional electric double layer capacitor using an aluminum foil as a current collector, a natural oxide film (passive film) made of aluminum oxide formed on the surface of the aluminum foil increases the resistance of the current collector. Conceivable. Moreover, since the surface of the aluminum foil is covered with an oxide film (passive film) made of aluminum oxide, an aluminum foil as a current collector and an electrode active material layer (coating material) formed on the surface of the aluminum foil The contact resistance value between and increases. As a result, there is a problem that ESR (equivalent series resistance) as an internal resistance of the electric double layer capacitor is increased.

  When the contact resistance value is increased, in a secondary battery and an electric double layer capacitor using an aluminum foil as a current collector, heat is likely to be generated during charging and discharging. Since the binder that binds the electrode active material deteriorates due to the generated heat, the adhesion between the electrode active material layer and the surface of the aluminum foil decreases. As a result, in the secondary battery and the electric double layer capacitor, a phenomenon occurs in which the electrode active material layer is peeled off during charging and discharging. There is a problem that this greatly affects characteristics such as the life of the secondary battery and the electric double layer capacitor.

  Further, when the contact resistance value is increased, the electric double layer capacitor has a larger capacity loss when discharged with a large current. For this reason, particularly in the case of power applications, a capacity loss occurs due to an increase in internal resistance including the contact resistance and the resistance of the current collector itself. As a result, there also arises a problem that the discharge time is shortened.

  In JP 2008-10856 A (hereinafter referred to as Patent Document 1), the front and back surfaces of the positive electrode are covered with aluminum fluoride in order to suppress the deterioration of the positive electrode and reduce the resistance.

  In JP-A-11-162470 (Patent Document 2), the surface of the current collector aluminum foil is roughened in order to improve the adhesion to the electrode active material.

JP 2008-10856 A JP 11-162470 A

  However, in patent document 1, the problem of the increase in resistance value resulting from the natural oxide film made of aluminum oxide formed on the surface of the aluminum foil is not solved.

  Also in Patent Document 2, peeling of the electrode active material layer cannot be sufficiently prevented.

  Accordingly, an object of the present invention is to suppress peeling of an electrode active material layer in a conductive member used as a material such as a current collector that constitutes an electrode of a secondary battery, a capacitor, etc., and the resistance of the electrode It is to provide a conductive member capable of lowering the resistance, an electrode including the conductive member, a secondary battery and a capacitor including the electrode, and a method for manufacturing the conductive member and the electrode.

  The conductive member according to the present invention is formed on an aluminum material, a passive layer including at least one of boron and nitrogen and aluminum formed on the surface of the aluminum material, and on the surface of the passive layer. A conductive diamond-like carbon layer.

  In the conductive member of the present invention, the passive layer preferably has a thickness of 5 nm to 200 nm.

  In the conductive member of the present invention, the thickness of the conductive diamond-like carbon layer is preferably 10 nm or more and 300 nm or less.

  The conductive member of the present invention may be a current collector.

  The electrode according to one aspect of the present invention includes the above-described conductive member and an electrode active material layer formed on the surface of the conductive diamond-like carbon layer in the conductive member.

  An electrode according to another aspect of the present invention comprises the above-described conductive member.

  The secondary battery according to the present invention includes any one of the electrodes described above.

  The capacitor according to the present invention includes any one of the electrodes described above.

  The method for manufacturing a conductive member according to the present invention includes the following steps.

  (A) In a space where discharge plasma containing at least one of boron ions and nitrogen ions is generated, at least one of boron ions and nitrogen ions is implanted into the surface of the aluminum material while the aluminum material is heated. Passivating layer forming step of forming a passivation layer containing at least one of boron and nitrogen and aluminum from the surface of the aluminum material toward the inside

  (B) Conductive diamond that forms a conductive diamond-like carbon layer on the surface of an aluminum material on which a passive layer is formed in a space where discharge plasma containing carbon ions is generated while the aluminum material is heated. Like carbon layer formation process

  In the method for producing a conductive member according to the present invention, in the passive layer forming step, the aluminum material is disposed in the space, and at least one of boron compound gas and nitrogen compound gas is introduced into the space. It is preferable to include forming a passive layer from the surface of the aluminum material toward the inside by generating discharge plasma in the vicinity of at least one of the surfaces and applying a negative bias voltage to the aluminum material.

  Further, in the method for producing a conductive member of the present invention, the conductive diamond-like carbon layer forming step includes disposing an aluminum material in the space and introducing a carbon compound gas into the space. It is preferable to include forming a conductive diamond-like carbon layer on the surface of the aluminum material on which the passive layer is formed by generating a discharge plasma near the surface of the aluminum material and applying a negative bias voltage to the aluminum material. .

  The electrode manufacturing method according to the present invention includes a step of forming an electrode active material layer on the surface of the conductive diamond-like carbon layer in the conductive member obtained by the above-described manufacturing method.

  ADVANTAGE OF THE INVENTION According to this invention, in the electrically-conductive member used as materials, such as a collector which comprises electrodes, such as a secondary battery and a capacitor, peeling of an electrode active material layer can be suppressed and resistance of an electrode is reduced. It becomes possible to make it.

It is sectional drawing which shows typically the cross section of the electrically-conductive member according to this invention. It is a conceptual diagram which shows the determination method of the thickness of the passive layer containing a boron and / or nitrogen from the density | concentration distribution of the boron atom and / or nitrogen atom in the aluminum material measured by secondary ion mass spectrometry (SIMS). . It is a figure which shows schematic structure of the plasma processing apparatus for manufacturing the electrically-conductive member of this invention. About the electrically-conductive member produced in Example 1 of this invention, the concentration distribution of the depth direction is shown from the surface of each element of carbon in an aluminum material measured by secondary ion mass spectrometry (SIMS), boron, and aluminum. FIG. It is the photograph which observed the cross section of the electrically-conductive member produced in Example 1 of this invention with the field emission scanning electron microscope (FE-SEM). It is sectional drawing which shows typically the electric double layer capacitor produced in Example 2 of this invention. About the electrically-conductive member produced in Example 3 of this invention, the concentration distribution of the depth direction is shown from the surface of each element of carbon in a aluminum material measured by secondary ion mass spectrometry (SIMS), nitrogen, and aluminum. FIG. It is a figure which shows AC impedance measured in the electric double layer capacitor produced by Example 2, Example 4, the comparative example 2, and the comparative example 4 of this invention. It is a figure which shows the relationship between a voltage and time as a result of the discharge test measured in the electric double layer capacitor produced in Example 2, Example 4, the comparative example 2, and the comparative example 4 of this invention.

  Hereinafter, embodiments of the conductive member of the present invention will be described.

  The conductive member of the present invention is used for a current collector that constitutes an electrode of a secondary battery, a capacitor or the like. The secondary battery is a secondary battery such as a lithium ion battery. The above capacitors are lithium ion capacitors, electric double layer capacitors, functional solid capacitors and the like. In the functional solid capacitor, the conductive member of the present invention is used for the current collector itself or the electrode itself.

  As shown in FIG. 1, a conductive member 101 according to an embodiment of the present invention is formed of an aluminum material 11 and from the surface of the aluminum material 11 toward the inside, and contains at least one of boron and nitrogen and aluminum. And a conductive diamond-like carbon layer 13 formed on the surface of the passive layer 12. The electrode 100 as one embodiment of the present invention includes a conductive member 101 and an electrode active material layer 14 formed on the surface of the conductive diamond-like carbon layer 13 in the conductive member 101.

  The aluminum material 11 is not particularly limited, but an aluminum foil generally used for a current collector can be used. When the aluminum material 11 is used as a current collector for a lithium ion secondary battery and an electric double layer capacitor as the purity of the aluminum material 11 is lower, particularly as the content of copper, iron, or silicon is increased, charging / discharging by an electrolyte is performed. Sometimes the corrosion amount of aluminum increases, the life of the electrode is reduced, and the battery characteristics may be greatly reduced. Therefore, the purity of the aluminum foil is not limited, but for the above reasons, it is preferably 99.0% by mass or more, more preferably 99.9% by mass or more.

  The thickness of the aluminum material 11 is not limited, but is preferably 10 μm or more and 100 μm or less. When the thickness of the aluminum material 11 is less than 10 μm, the aluminum foil may be broken or cracked in the process of roughening the surface of the aluminum foil or in other manufacturing processes. When the thickness of the aluminum material 11 exceeds 100 μm, there is no inconvenience in characteristics, but in terms of volume and weight, that is, the inconvenience that the size of the battery itself increases and becomes heavy when incorporated in the battery. In addition, it is disadvantageous in terms of manufacturing cost, that is, it is not preferable in that the material cost increases because the amount of aluminum foil to be used increases.

  In one embodiment of the conductive member 101 of the present invention, only boron ions, only nitrogen ions, or boron ions and nitrogen ions are implanted into the surface of the aluminum material 11, and aluminum and boron, aluminum and nitrogen, or A passive layer 12 containing aluminum, boron and nitrogen is formed from the surface of the aluminum material 11 toward the inside.

  When boron ions are implanted into the surface of the aluminum material 11, not all aluminum present on the surface of the aluminum material 11 is bonded to boron, but at least a part of aluminum is bonded to boron to form aluminum boride. It is assumed that Hereinafter, in this specification, for convenience, the passivation layer 12 formed by implanting boron ions into the surface of the aluminum material 11 is referred to as an aluminum boride layer.

  Aluminum boride crystals have a graphite-like layer structure, with aluminum atoms intercalated between the layers, like a metal along an axis parallel to the hexagonal plane that is the crystal plane of aluminum boride. It is known that it exhibits excellent conductivity. Depending on the production method, the aluminum boride layer is a passive film having excellent corrosion resistance that is not affected by concentrated nitric acid and concentrated hydrochloric acid. By forming an aluminum boride layer as the passive layer 12 on the surface of the aluminum material 11, the deterioration of the current collector due to corrosion in the electrolyte is suppressed, and at the same time, the conductivity laminated on the surface of the passive layer 12 Contact resistance with the diamond-like carbon layer 13 can be significantly reduced. Moreover, by forming the hydrophilic conductive diamond-like carbon layer 13, the adhesive force with the electrode active material layer 14 can be improved, and peeling of the electrode active material layer 14 can be suppressed.

  The aluminum boride layer as the passive layer 12 can be formed by injecting boron ions into the surface of the aluminum material 11 by applying a negative bias voltage to the aluminum material 11 in a discharge plasma containing boron ions. .

For example, the conceptual diagram of the result of having measured the concentration distribution from the surface of the aluminum material 11 of the boron atom which injected the aluminum material 11 by applying the negative pulse voltage of 20 kV by the secondary ion mass spectrometry (SIMS). As shown in FIG. As shown in FIG. 2, the concentration of implanted boron atoms decreases from the surface of the aluminum material 11 toward the inside. A so-called gradient distribution is formed for the so-called boron atom concentration distribution. When the temperature of the aluminum material 11 at the time of ion implantation increases, the implanted boron diffuses deeply into the aluminum material 11, so that the thickness of the aluminum boride layer increases as compared with the case where it is implanted at room temperature. An aluminum boride (AlB ₂ ) layer close to the stoichiometric composition is formed on the outermost surface of the aluminum material 11, but aluminum boride deviating from the stoichiometric composition is generated inside the aluminum material 11. It is done. Therefore, the thickness of the aluminum boride layer by boron ion implantation is defined as a region where the concentration of implanted boron atoms is 1/2 or more of the concentration of the outermost surface of the aluminum material 11. That is, as shown in FIG. 2, the thickness t of the aluminum boride layer as passivation layer 12, when the concentration of boron atoms in the outermost surface of the aluminum material 11, C _0, the concentration of boron atoms is C _0/2 It is defined as the distance between the position of the depth D ₁ when = C ₁ and the position of the outermost surface of the aluminum material 11.

  The thickness of the aluminum boride layer can be controlled by the energy of implanted ions, that is, the negative bias voltage applied to the aluminum material 11 and the temperature of the aluminum material 11. The thickness can also be controlled by the voltage application time. The thickness of the aluminum boride layer is preferably 5 nm or more and 200 nm or less, more preferably 10 nm or more and 60 nm or less.

  Ordinary aluminum nitride (AlN) is the most stable material against oxidation among nitrides, but is an insulating material. Accordingly, an aluminum nitride layer having corrosion resistance can be formed by a normal manufacturing method such as sputtering or CVD, but it is difficult to form an aluminum nitride layer having conductivity as well as corrosion resistance. In the conductive member 101 of the present invention, the aluminum nitride layer as the passivating layer 12 applies a negative bias voltage to the aluminum material 11 in the discharge plasma containing nitrogen ions in the same manner as the formation of the aluminum boride layer. Then, it can be formed by implanting nitrogen ions into the surface of the aluminum material 11. The concentration distribution of the implanted nitrogen atoms from the surface of the aluminum material 11 is almost the same as that in the case of boron ion implantation shown in FIG. 2, and the concentration of the implanted nitrogen atoms is from the surface of the aluminum material 11 toward the inside. Decrease.

  In the formation of the aluminum nitride layer by nitrogen ion implantation, the ratio of nitrogen element to aluminum element can be made smaller than the stoichiometric composition by adjusting the amount of nitrogen ion implantation. By making the ratio of the nitrogen element 50 to 70% of the aluminum element, an aluminum nitride layer as the low-resistance passive layer 12 having a resistivity of 10 Ω · cm to 1 kΩ · cm can be formed. In this way, by forming an aluminum nitride layer as the passive layer 12 on the surface of the aluminum material 11, the deterioration of the current collector due to corrosion in the electrolytic solution is suppressed, and at the same time laminated on the surface of the passive layer 12. The contact resistance with the conductive diamond-like carbon layer 13 can be significantly reduced. Therefore, peeling of the electrode active material layer 14 can be suppressed, and the resistance of the electrode 100 can be reduced.

  The thickness of the aluminum nitride layer is preferably 5 nm to 200 nm, more preferably 10 nm to 60 nm.

  By forming the passivating layer 12 made of the aluminum boride layer or the aluminum nitride layer by the method described above, the surface of the aluminum material 11 is oxidized in the subsequent step of forming the conductive diamond-like carbon layer 13. It is possible to suppress the formation of an oxide film due to, and to reduce the contact resistance with the conductive diamond-like carbon layer 13 laminated on the surface of the passive layer 12.

  Furthermore, a negative bias voltage is applied to the aluminum material 11 in a discharge plasma containing boron ions and nitrogen ions, and boron ions and nitrogen ions are implanted into the surface of the aluminum material 11, so that the surface of the aluminum material 11 is introduced into the interior. A passive layer 12 containing boron and nitrogen can be formed. Further, by injecting boron ions after injecting nitrogen ions into the surface of the aluminum material 11, the passive layer 12 having a lower resistivity can be formed, and the conductive layer laminated on the surface of the passive layer 12. Contact resistance with the diamond-like carbon layer 13 can be reduced. Therefore, peeling of the electrode active material layer 14 can be suppressed, and the resistance of the electrode 100 can be further reduced.

In the case where only nitrogen ions or boron ions and nitrogen ions are implanted, and a passive layer 12 containing aluminum and nitrogen or aluminum, boron and nitrogen is formed from the surface of the aluminum material 11 toward the inside. As shown in FIG. 2, the thickness t of the passive layer 12 is such that the concentration of nitrogen atoms on the outermost surface of the aluminum material 11 or the concentration of nitrogen atoms when the concentration of boron atoms and nitrogen atoms is C _0. Alternatively, it is defined as the distance between the position of the depth D _{1 and} the position of the outermost surface of the aluminum material 11 when the concentration of boron atom and nitrogen atom is C _0/2 = C ₁ . Moreover, the passive layer 12 may contain elements other than boron and nitrogen. Examples of other elements include oxygen and fluorine. Other elements contained in the passive layer 12 do not affect the above-described effects.

The conductive diamond-like carbon layer 13 is formed by heating the aluminum material 11 after forming the passive layer 12 to a temperature of 200 to 450 ° C. and holding it in a discharge plasma of a hydrocarbon-based gas such as methane gas or acetylene gas. The conductive diamond-like carbon layer 13 can be formed on the surface of the aluminum material 11 by applying a negative pulse voltage of 500 V to 20 kV, preferably 1 kV to 15 kV, to the aluminum material 11. That is, carbon ions and radicals generated in the discharge plasma are deposited on the surface of the aluminum material 11. A diamond-like carbon layer is formed by bombarding the deposit with carbon ions. At this time, an ordinary diamond-like carbon layer formed by keeping the temperature of the aluminum material 11 below 200 ° C. exhibits a very high resistivity. A high diamond-like carbon layer can be formed. The resistivity of the conductive diamond-like carbon layer 13 greatly depends on the temperature of the aluminum material 11. In order to form the conductive diamond-like carbon layer 13 having a resistivity of 1 Ω · cm or less, the temperature of the aluminum material 11 is low. It is desirable that the temperature is 300 ° C. or higher. Further, it has been confirmed that the conductive diamond-like carbon layer 13 formed at a temperature of the aluminum material 11 of 300 ° C. or higher is a mixture of sp ² bonds and sp ³ bond nanocrystals and amorphous carbon. These ratios vary depending on the energy of the irradiated ions and the temperature of the aluminum material 11. The conductive diamond-like carbon layer 13 is presumed to be a mixture of columnar carbon having a size of 10 to 50 nm, nanowall (sp ² bond), nano diamond (sp ³ bond), and amorphous carbon.

  The resistivity of the conductive diamond-like carbon layer 13 in the conductive member 101 of the present invention is preferably 1 mΩ · cm to 1000 mΩ · cm, more preferably 1 mΩ · cm to 100 mΩ · cm. The thickness of the conductive diamond-like carbon layer 13 is not particularly limited, but is preferably 10 nm or more and 300 nm or less, and more preferably 10 nm or more and 100 nm or less. The thickness of the conductive diamond-like carbon layer 13 can be controlled by the energy of implanted ions, that is, the negative bias voltage applied to the aluminum material 11 and the temperature of the aluminum material 11. The thickness can also be controlled by the voltage application time. According to the present invention, a conductive diamond-like material is directly applied to the surface of a conductive aluminum boride layer or aluminum nitride layer as the passive layer 12 formed by ion implantation from the surface of the aluminum material 11 toward the inside. By joining the carbon layer 13, it is possible to manufacture a conductive member 101 such as a current collector covered with the conductive diamond-like carbon layer 13 that is also passive while reducing the contact resistance between them. Therefore, according to the present invention, peeling of the electrode active material layer 14 can be suppressed in the conductive member 101 used as a material such as a current collector constituting an electrode of a secondary battery, a capacitor, etc., and the electrode It becomes possible to reduce the resistance of 100. The conductive diamond-like carbon layer 13 may contain elements other than carbon. Other elements include boron, aluminum, nitrogen, fluorine, and oxygen. Other elements contained in the conductive diamond-like carbon layer 13 do not affect the above-described effects.

Next, the electrode active material layer 14 is activated carbon powder, lithium cobaltate (LiCoO ₂ ), lithium manganate (LiMnO ₂ ), lithium permanganate (LiMn ₂ O ₄ ), nickel oxide as an electrode active material. The surface of the conductive member 101, that is, the surface of the conductive diamond-like carbon layer 13, using a lithium transition metal oxide such as lithium (LiNiO ₂ ) or lithium nickel cobaltate (LiN _x Co _(1-x) O ₂ ) as a paste. It is formed by applying to. This paste can be prepared using known techniques. For example, it can be obtained by kneading activated carbon powder, if necessary, conductive carbon powder as a conductive additive, cellulose as a binder, fluorine resin, etc. in water and an organic solvent. The paste film applied to the surface of the conductive member 101 is appropriately dried and heated to cure the binder, and is fixed to form the electrode active material layer 14.

  Details of the components of the paste applied to the surface of the conductive member 101 to form the electrode active material layer 14 are as follows.

  The raw material of the activated carbon powder as the electrode active material constituting the electrode active material layer 14 is not particularly limited. For example, plant-based wood, coconut shell, fossil fuel-based coal, heavy petroleum oil, or the like Examples include pyrolyzed coal, petroleum-based pitch, petroleum coke, and the like. The activated carbon powder is obtained by carbonizing the above raw material and then activating treatment. This activation method is roughly classified into a gas activation method and a chemical activation method. However, the manufacturing method of the activated carbon powder used for this invention is not limited to said method.

  The particle diameter of the activated carbon powder is not particularly limited, but is usually 1 μm or more and 10 μm or less, and preferably 2 μm or more and 6 μm or less. Moreover, although the shape of activated carbon powder is not specifically limited, As a kind of shape, there are mainly granular activated carbon and fibrous activated carbon. Examples of granular activated carbon include crushed charcoal, granular charcoal, and molded charcoal. Examples of fibrous activated carbon include felt, fiber, cloth, and fiber.

The lithium transition metal oxide as the electrode active material constituting the electrode active material layer 14 is also not particularly limited. For example, lithium cobaltate (LiCoO ₂ ), lithium manganate (LiMnO ₂ ), lithium permanganate (LiMn ₂₎ Examples thereof include lithium transition metal oxides such as O ₄ ), lithium nickel oxide (LiNiO ₂ ), and lithium cobalt oxide (LiN _x Co _(1-x) O ₂ ).

Although content of said electrode active material is not specifically limited, It is preferable that they are 5 mass% or more and 60 mass% or less in a paste, More preferably, it should just be 15 mass% or more and 50 mass% or less . Moreover, the electrode active material may contain only activated carbon powder or a lithium transition metal oxide, and may contain both. Moreover, in this invention, it does not exclude using electrode active materials other than activated carbon powder and a lithium transition metal oxide as an electrode active material.

  The conductive auxiliary agent is not particularly limited, and carbon black and graphite can be used as the conductive carbon material. Examples of carbon black include acetylene black, ketjen black, and thermal black. Examples of graphite include natural graphite and artificial graphite. As the conductive assistant, only one kind may be used from the above-mentioned carbon black and graphite, or two or more kinds may be used in combination. What is necessary is just to add this conductive support agent as needed. Although content of a conductive support agent is not specifically limited, It is preferable that it is 0.5 to 40 mass% in a paste, More preferably, it may be 1.0 to 20 mass%.

  The binder is not particularly limited, and examples thereof include fluorine rubber, diene rubber, styrene rubber, nitrile rubber, acrylic rubber, butyl rubber, thiocol, fluorine resin, polyolefin resin, acrylic resin, nitrile resin, and polyester resin. be able to. Although content of a binder is not specifically limited, It is preferable that it is 0.5 to 50 mass% in a paste, More preferably, it may be 1.0 to 30 mass%.

  Although it does not specifically limit as a solvent, Water and an organic solvent can be used. Examples of the organic solvent include N-methylpyrrolidone (NMP), N, N-dimethylformamide, dimethylacetamide, alcohols and the like. Although content of a solvent is not specifically limited, 10 mass% or more and 90 mass% or less in a paste, More preferably, what is necessary is just 20 mass% or more and 80 mass% or less.

  The specific method for mixing the paste is not particularly limited, and examples thereof include a blade mixer, a ball mill, a bead mill, and a rotating / revolving mixer.

  The manufacturing method of the conductive member 101 according to one embodiment of the present invention includes the following steps.

  (A) In a space where discharge plasma containing at least one of boron ions and nitrogen ions is generated, at least one of boron ions and nitrogen ions is heated on the surface of the aluminum material 11 on the surface of the aluminum material 11. Passive layer forming step of forming a passive layer 12 containing at least one of boron and nitrogen and aluminum from the surface to the inside of the aluminum material 11 by implantation.

  (B) A conductive diamond-like carbon layer 13 is formed on the surface of the aluminum material 11 on which the passive layer 12 is formed in a space where discharge plasma containing carbon ions is generated, with the aluminum material 11 being heated. Conductive diamond-like carbon layer forming process

  In the method for manufacturing the conductive member 101 of the present invention, the passive layer forming step is such that the aluminum material 11 is disposed in the space, and at least one of the boron compound gas and the nitrogen compound gas is introduced into the space. Including forming a passive layer 12 from the surface of the aluminum material 11 toward the inside by generating discharge plasma in the vicinity of at least one surface of the aluminum material 11 and applying a negative bias voltage to the aluminum material 11. It is preferable.

  Further, in the method for manufacturing the conductive member 101 of the present invention, in the conductive diamond-like carbon layer forming step, the aluminum material 11 is placed in a state where the aluminum material 11 is disposed in the space and the carbon compound gas is introduced into the space. The conductive diamond-like carbon layer 13 is formed on the surface of the aluminum material 11 on which the passive layer 12 is formed by generating discharge plasma in the vicinity of at least one surface of the material and applying a negative bias voltage to the aluminum material 11. It is preferable to include.

  The manufacturing method of the electrode 100 according to the present invention includes a step of forming the electrode active material layer 14 on the surface of the conductive diamond-like carbon layer 13 in the conductive member 101 obtained by the above manufacturing method.

  More specifically, the manufacturing method of the conductive member 101 of the present invention includes the following steps.

  (I) The process of conveying the aluminum material 11 to the space where plasma processing is performed

  (Ii) Step of heating the aluminum material 11

  (Iii) A step of implanting boron ions or / and nitrogen ions into the surface of the aluminum material 11 in a discharge plasma containing boron ions or / and nitrogen ions to form a passive layer 12 containing aluminum and boron or / and nitrogen.

  (Iv) Forming the conductive diamond-like carbon layer 13 on the surface of the aluminum material 11 in the discharge plasma containing carbon ions

  Hereinafter, the manufacturing method of the conductive member 101 of the present invention will be described using an example of a plasma processing apparatus capable of performing the steps (i) to (iv).

  As shown in FIG. 3, the plasma processing apparatus 200 includes a vacuum vessel 20, a vacuum exhaust unit 22, a working gas introduction unit 23, a plasma generation unit (including a high frequency power supply 26, a matching unit 27, and a high frequency antenna 24). And a bias voltage applying means (hereinafter referred to as a bias power supply) 28. The vacuum vessel 20 includes a plasma processing chamber 21, and an aluminum material 11 is disposed as a workpiece 25 in the plasma processing chamber 21. In the plasma processing apparatus 200, a high-frequency antenna 24 is disposed to face at least one surface of the workpiece 25, and the high-frequency antenna 24 is connected to a high-frequency power source 26 through a matching unit 27. The workpiece 25 is connected to a bias power source 28 through a feedthrough 29. The plasma processing apparatus shown in FIG. 3 shows one embodiment, and the apparatus for manufacturing the conductive member 101 of the present invention is not limited to the plasma processing apparatus shown in FIG.

  Depending on the area of the workpiece 25 to be processed, the high-frequency antenna 24 includes a plurality of U-shaped inductively coupled antennas, ladder-type antennas, or small U-shaped inductively coupled antennas in parallel or in series. Can be placed and used. A capacitively coupled antenna can also be used, but an inductively coupled high frequency antenna is suitable for generating high density plasma. By disposing the high-frequency antenna 24 so as to face both surfaces of the workpiece 25, an aluminum boride layer and / or an aluminum nitride layer as the passive layer 12 simultaneously on both surfaces of the aluminum material 11 as the workpiece 25, Alternatively, the conductive diamond-like carbon layer 13 can be formed.

First, a process for forming a conductive aluminum boride layer as the passive layer 12 will be described with reference to FIG. The aluminum material 11 as the workpiece 25 is transported into the plasma processing chamber 21 by a transport system, for example, a roll-to-roll system. The plasma processing chamber 21 is evacuated to a high vacuum at a pressure of 10 ⁻³ Pa or less by a vacuum evacuation unit 22 in advance. The workpiece 25 is heated in advance to a predetermined temperature, for example, 200 to 400 ° C. by a workpiece heating means (not shown) installed opposite to the workpiece 25, so that the workpiece 25 is heated. From the gas. During the plasma processing, since a negative pulse voltage is applied to the workpiece 25, heat accompanying ion irradiation is applied to the workpiece 25. Therefore, it is preferable to measure the temperature of the workpiece 25 with a radiation thermometer or the like, and to control the workpiece heating means based on the measured temperature so as to keep the temperature of the workpiece 25 at a predetermined temperature. .

  Next, an inert gas, for example, argon gas, is introduced into the plasma processing chamber 21 by the working gas introduction means 23, the gas pressure is set to a predetermined pressure, and high frequency power is supplied to the high frequency antenna 24 for discharge. Excites the plasma. A negative pulse voltage of a maximum of 20 kV is applied to the aluminum material 11 as the workpiece 25 to clean the surface of the aluminum material 11.

Then, in order to form an aluminum boride layer as the passive layer 12 from the surface of the aluminum material 11 toward the inside, boron compound gas such as BF ₃ , BCl ₃ , B ₂ H _{6 is} introduced into the plasma processing chamber 21. The gas pressure is adjusted to 0.1 to 100 Pa, preferably 0.3 to 30 Pa. At this time, hydrogen gas, argon gas, or the like can be added. A surface cleaning effect can be obtained by adding these gases. High frequency power is supplied from the high frequency power source 26 to the high frequency antenna 24 via the matching unit 27 to generate discharge plasma. At the same time, by applying a negative pulse voltage from the bias power supply 28 to the aluminum material 11 as the workpiece 25 through the feedthrough 29, boron ions are implanted into the surface of the aluminum material 11.

  As the high frequency power source 26, it is preferable to use a high frequency power source of 10 to 60 MHz and an output of 300 W to 5 kW. Further, as the high frequency power, high frequency power that continuously oscillates or high frequency power that oscillates intermittently with a repetition frequency of 0.5 to 10 kHz can be used. The bias power supply is preferably a bias power supply that can apply a negative pulse voltage having an output voltage for ion implantation or film formation of 1 to 20 kV, a pulse width of 1 to 30 μs, and a repetition frequency of 0.5 to 10 kHz.

  Further, a high concentration of boron ions can be implanted by applying a negative pulse voltage in synchronization with the repetition period of the high-frequency power source. For example, in the case of using 13.56 MHz high-frequency power that intermittently oscillates with a repetition period of 500 μs (2 kHz) and an oscillation duration of 100 μs, a negative pulse voltage is applied as a bias voltage within 50 μs immediately after the pulse oscillation. Boron ions can be implanted with a high-density ion current. Further, when the above conditions are applied to the formation of the conductive diamond-like carbon layer 13 as a film, it is possible to form a film at a film formation rate of 20 nm / min.

The formation of the aluminum nitride layer as the passive layer 12 is similar to the formation of the aluminum boride layer described above by introducing a nitrogen compound gas such as nitrogen gas (N ₂ ) or ammonia gas (NH ₃ ) as a source gas. The ion implantation can be performed under the following conditions. Since the mass of nitrogen atoms is substantially the same as that of boron atoms, the implantation depth of nitrogen ions and the thickness of the aluminum nitride layer may be considered to be substantially equivalent. The aluminum boride layer and the aluminum nitride layer are excellent in chemical resistance and act as a passive film having conductivity.

  Next, formation of the conductive diamond-like carbon layer 13 will be described. The conductive diamond-like carbon layer 13 can be formed in substantially the same manner as the formation of the aluminum boride layer and the aluminum nitride layer. After the formation of the aluminum boride layer and / or the aluminum nitride layer, the raw material for forming the conductive diamond-like carbon layer 13 by subsequently heating the temperature of the aluminum material 11 as the workpiece 25 to 200 to 450 ° C. in advance. A gas is introduced into the plasma processing chamber 21, and the gas pressure is adjusted to a predetermined gas pressure. As the source gas, a gas mainly composed of at least one selected from the group of hydrocarbon compounds consisting of methane, ethane, ethylene, acetylene, benzene, toluene, cyclohexanone, chlorobenzene and the like can be used. The gas pressure is 0.1 to 100 Pa, preferably 0.3 to 30 Pa. Moreover, hydrogen gas, argon gas, etc. can be added as needed. High frequency power is supplied from the high frequency power supply 26 to the high frequency antenna 24 via the matching unit 27 to generate discharge plasma, and at the same time, a negative pulse high voltage is applied to the aluminum material 11 as the workpiece 25 to form conductive diamond. A like carbon layer 13 is formed.

  Through the above manufacturing process, the conductive member 101 in which the conductive passive layer 12 and the conductive diamond-like carbon layer 13 made of an aluminum boride layer and / or an aluminum nitride layer are laminated on the surface of the aluminum material 11 by ion implantation. Can be manufactured. Further, by doping the conductive diamond-like carbon layer 13 with boron or nitrogen impurity atoms, the resistivity can be reduced by about one digit. Forming the surface of the superhydrophilic conductive diamond-like carbon layer 13 having a water repellent angle of 30 ° or less by adding a gas containing oxygen and nitrogen at the final stage of the formation process of the conductive diamond-like carbon layer 13 Thus, the adhesive strength with the electrode active material layer 14 can be improved.

  By forming the electrode active material layer 14 on the surface of the current collector as the conductive member 101 of the present invention obtained by the above-described method, the electrodes of the secondary battery and the capacitor can be manufactured. In order to form the electrode active material layer 14, a paste containing the electrode active material is applied to the surface of the current collector as the conductive member 101. The constituent components of the paste and the manufacturing method are as described above, but the method of applying and drying the paste will be described below.

  The method for applying the paste to the current collector is not particularly limited, and for example, the paste can be applied by a blade method, a reverse roll method, a knife method, a gravure roll method, or the like. Further, as a coating method, a spin coating method, a bar coating method, a flow coating method, a dip coating method, or the like can also be employed. Moreover, as other adhesion methods, methods such as an extrusion method can be employed.

  The amount of the paste applied to the current collector is not particularly limited, but the thickness of the electrode active material layer 14 formed after drying and removing the solvent (or dispersion medium) contained in the paste is usually about 5 μm to 1 mm. As long as the amount of In particular, when manufacturing a capacitor utilizing the low resistance characteristics of the conductive member 101 of the present invention, the thickness of the electrode active material layer 14 is preferably about 5 to 30 μm.

  After applying the paste to the current collector, the solvent component contained in the paste is preferably removed by drying. The method for drying and removing is not particularly limited, and there are methods such as natural drying and drying by heat. Considering the drying efficiency, a method using a vacuum drying furnace is suitable, and it is desirable to perform the drying at a temperature of 60 to 200 ° C. under a low pressure of 1 to 100 kPa.

  As described above, the electrode 100 of the secondary battery and the capacitor can be manufactured by forming the electrode active material layer 14 on the surface of the current collector as the conductive member 101.

  Although it does not specifically limit as a secondary battery, For example, a lithium ion battery etc. are mentioned. Although it does not specifically limit as a capacitor, For example, a lithium ion capacitor, an electric double layer capacitor, etc. are mentioned. The electrode 100 of the present invention can be applied to any conventionally known electric double layer capacitor. For example, the electrode 100 can be applied to any type of electric double layer capacitor such as a coin type, a wound type, and a multilayer type. it can. In such an electric double layer capacitor, for example, an electrode sheet is cut into a desired size and shape, laminated or wound with a separator interposed between both electrodes, inserted into a container, and an electrolyte is injected. And it can manufacture by caulking a seal using a sealing board and a gasket.

  According to the following examples, a current collector as the conductive member 101 of the present invention, the electrode 100 of the present invention, and an electric double layer capacitor including the electrode 100 were produced. For comparison, a current collector was prepared using etched aluminum foil according to the following comparative example, an electrode was prepared, and an electric double layer capacitor provided with the electrode was prepared.

Example 1
In Example 1, an aluminum material 11 (JIS 1085) having an aluminum content of 99.9% by mass and a thickness of 20 μm was prepared. An aluminum material 11 is provided on an aluminum frame (not shown) fixed to an insulating support (not shown), and a pair of inductively coupled high frequency is used as a workpiece 25 shown in FIG. The antenna 24 is mounted so as to face the substantially central portion. Next, the inside of the plasma processing chamber 21 was evacuated to create a high vacuum with a pressure of 10 ⁻³ Pa or less. And the gas was fully discharged | emitted from the workpiece 25 by hold | maintaining the workpiece 25 at the temperature of 240 degreeC. Thereafter, a mixed gas of argon and hydrogen was introduced into the plasma processing chamber 21, the gas pressure was adjusted to a pressure of 0.5 Pa, and high frequency power of 700 W was supplied to the high frequency antenna 24 to excite the discharge plasma. . By applying a negative pulse voltage having a peak value of 12 kV, a repetition frequency of 2 kHz, and a pulse width of 5 μs to the aluminum material 11 as the workpiece 25 in a state where the discharge plasma is excited, the ion bombardment for 15 minutes is performed. The surface was cleaned by

  Subsequently, with the aluminum material 11 maintained at a temperature of 260 ° C., the raw material gas was switched to a mixed gas of boron trifluoride and hydrogen (flow rate ratio 1: 1), and the gas pressure was adjusted to 0.3 Pa. A high frequency power of 13.56 MHz that intermittently pulsates with a repetition frequency of 2 kHz and an oscillation duration of 50 μs was supplied to the high frequency antenna 24 to excite the discharge plasma. By applying a negative pulse voltage having a peak value of 12 kV and a pulse width of 5 μs to the aluminum material 11 for 30 minutes in synchronization with the pulse oscillation of the high-frequency power in a state where the discharge plasma is excited, An aluminum boride layer as layer 12 was formed.

  FIG. 4 is measured by secondary ion mass spectrometry (SIMS) for a conductive member 101 in which a conductive diamond-like carbon layer 13 is formed as described later after forming an aluminum boride layer as the passive layer 12. It is a figure which shows concentration distribution of the depth direction from the surface of each element of carbon (C) in the aluminum material 11, boron (B), and aluminum (Al). A substantially flat region of the carbon concentration is a conductive diamond-like carbon layer, and a concentration curve having a peak at a depth of about 80 nm from the surface shows a boron element concentration distribution. The distance from the surface of the conductive member 101 to the peak depth position of the boron element concentration is considered as the thickness of the conductive diamond-like carbon layer. Therefore, the depth position of the peak of the boron element concentration corresponds to the position of the outermost surface of the aluminum material 11. From FIG. 4, when determining the thickness t of the aluminum boride layer as the passive layer 12 according to the method for determining the thickness of the passive layer shown in FIG. 2, the thickness of the aluminum boride layer was about 30 nm. .

  Next, a conductive diamond-like carbon layer 13 was formed on the passive layer 12 as follows. The aluminum material 11 is maintained at a temperature of 280 ° C., and a mixed gas of methane, acetylene and nitrogen (flow rate ratio 2: 2: 1.5) is introduced into the plasma processing chamber 21 as a raw material gas, and the gas pressure is reduced to 0. The discharge plasma was excited by supplying high frequency power of 13.56 MHz that was intermittently pulsed with a repetition frequency of 2 kHz and an oscillation duration of 100 μs to the high frequency antenna 24. By applying a negative pulse voltage having a peak value of 12 kV and a pulse width of 5 μs to the aluminum material 11 for 30 minutes in synchronization with the pulse oscillation of the high-frequency power in a state where this discharge plasma is excited, a conductive diamond-like A carbon layer 13 was formed. In this manner, a current collector material as the conductive member 101 of the present invention was produced.

  FIG. 5 is a photograph of a cross section of the obtained conductive member 101 observed with a field emission scanning electron microscope (FE-SEM). As shown in FIG. 5, the region of the aluminum material 11 (Al) including the passive layer 12 and the region of the conductive diamond-like carbon layer 13 (DLC) could be observed. The thickness of the conductive diamond-like carbon layer 13 (DLC) measured from the photograph is about 60 nm at the center of the conductive member 101 shown in FIG. 5A, and the end of the conductive member 101 shown in FIG. Part was about 100 nm.

Further, in order to measure the resistivity of the obtained conductive diamond-like carbon layer 13, a conductive diamond was formed on a glass substrate having a size of 5 cm × 2 cm under the same film formation conditions as those of the conductive diamond-like carbon layer 13 described above. A like carbon layer was formed. As a result of measuring the resistivity of the obtained conductive diamond-like carbon layer by a four-terminal method (manufactured by Mitsubishi Chemical Analytech Co., Ltd., Loresta GP), the resistivity was about 80 mΩ · cm .

  The obtained conductive member 101 was immersed in a 1% hydrofluoric acid solution. As a result, no gas generation due to corrosion of the conductive member 101 was observed even after 15 minutes.

  Further, the electrode active material layer 14 was formed on the current collector as the obtained conductive member 101 as follows.

  86 parts by mass of lithium iron phosphate as an electrode active material, 7 parts by mass of a conductive additive, and 140 parts by mass of an N-methylpyrrolidone (NMP) solution containing a binder having a concentration of 5% by mass were added and mixed. Thereafter, 178 parts by mass of NMP was further added to prepare a paste containing an electrode active material. Next, this paste is applied to one side of the conductive diamond-like carbon layer 13 of the conductive member 101 obtained above and dried to form the electrode active material layer 14, and the electrode 100 having a thickness of 45 μm. Was made.

  The obtained electrode 100 was immersed in a 1% hydrofluoric acid solution. As a result, even after 15 minutes, neither gas generation due to corrosion of the conductive member 101 nor separation of the electrode active material layer 14 from the conductive member 101 was observed.

(Example 2)
91.5 parts by mass of activated carbon powder as an electrode active material, 4.5 parts by mass of a conductive additive, and 23 parts by mass of an aqueous solution containing a binder having a concentration of 20% by mass were added, and then adjusted to 1.2% by mass. 150 parts by mass of a thickener carboxymethyl cellulose aqueous solution was added and mixed, and 210 parts by mass of distilled water for adjusting the concentration was further added to prepare a paste containing an electrode active material. Next, this paste is applied to one side of the conductive diamond-like carbon layer 13 of the conductive member 101 of Example 1 obtained above, and dried to form the electrode active material layer 14. A 45 μm electrode 100 was produced.

The obtained electrode 100 was cut into a rectangular shape having a plane area of 8 cm × 2 cm, the electrode active material layer 14 in a region from one end edge to a length of 3 cm was removed, and an electrode active material having a plane area of 10 cm ² was removed. A strip-shaped electrode having the material layer 14 and a terminal portion having a plane area of 6 cm ² was produced.

The obtained two strip-shaped electrodes were opposed to each other with a separator formed of cellulose having a thickness of 30 μm and a flat area of 6 cm × 3 cm, and were laminated in the order of electrodes, separators, and electrodes in a laminate film. Thereafter, 1 ml of an electrolyte solution of 1.5 M TEMA BF ₄ / PC was injected into the separator, and heat sealing was performed to produce a film cell of an electric double layer capacitor.

  Specifically, an electric double layer capacitor is configured as shown in FIG. Each of the pair of electrodes includes a current collector as the conductive member 101 and an electrode active material layer 14 formed thereon. A separator 16 is interposed between the pair of electrodes, and an electrolytic solution 15 is present. A cation (+) and an anion (-) are present in the electrolyte solution 15.

(Example 3)
In Example 3, an aluminum material 11 (JIS 1085) having an aluminum content of 99.9% by mass and a thickness of 20 μm was prepared. An aluminum material 11 is provided on an aluminum frame (not shown) fixed to an insulating support (not shown), and a pair of inductively coupled high frequency is used as a workpiece 25 shown in FIG. The antenna 24 is mounted so as to face the substantially central portion. Next, the inside of the plasma processing chamber 21 was evacuated to a high vacuum of 10 −3 Pa or less. And the gas was fully discharged | emitted from the workpiece 25 by hold | maintaining the workpiece 25 at the temperature of 330-360 degreeC. Thereafter, a mixed gas of argon and hydrogen was introduced into the plasma processing chamber 21, the gas pressure was adjusted to a pressure of 0.5 Pa, and high frequency power of 700 W was supplied to the high frequency antenna 24 to excite the discharge plasma. . By applying a negative pulse voltage having a peak value of 8 kV, a repetition frequency of 2 kHz, and a pulse width of 5 μs to the aluminum material 11 as the workpiece 25 in a state where the discharge plasma is excited, ion bombardment for 30 minutes is performed. The surface was cleaned by

  Subsequently, the raw material gas is switched to a mixed gas of argon, hydrogen and nitrogen (flow rate ratio 2: 3: 3) while the aluminum material 11 is maintained at a temperature of 330 to 360 ° C., and the gas pressure is set to 0.3 Pa. The high frequency power of 13.56 MHz that intermittently pulsates with a repetition frequency of 2 kHz and an oscillation duration of 50 μs was supplied to the high frequency antenna 24 to excite the discharge plasma. By applying a negative pulse voltage having a peak value of 8 kV and a pulse width of 5 μs to the aluminum material 11 for 30 minutes in synchronism with the pulse oscillation of the high frequency power in a state where the discharge plasma is excited, An aluminum nitride layer as the layer 12 was formed.

  FIG. 7 is measured by secondary ion mass spectrometry (SIMS) on a conductive member 101 in which a conductive diamond-like carbon layer 13 is formed as described later after forming an aluminum nitride layer as the passive layer 12. It is a figure which shows concentration distribution of the depth direction from the surface of each element of carbon (C) in a aluminum material 11, nitrogen (N), and aluminum (Al). The substantially flat region of the carbon concentration is a conductive diamond-like carbon layer, and the concentration curve having a peak at a depth of about 20 nm from the surface shows the concentration distribution of nitrogen element. The distance from the surface of the conductive member 101 to the peak position of the nitrogen element concentration is considered to be the thickness of the conductive diamond-like carbon layer. Therefore, the depth position of the peak of the nitrogen element concentration corresponds to the position of the outermost surface of the aluminum material 11. From FIG. 7, when the thickness t of the aluminum nitride layer as the passive layer 12 was determined according to the method for determining the thickness of the passive layer shown in FIG. 2, the thickness of the aluminum nitride layer was about 7 nm.

  Next, a conductive diamond-like carbon layer 13 was formed on the passive layer 12 as follows. The aluminum material 11 is maintained at a temperature of 330 to 360 ° C., and a mixed gas of methane, acetylene and nitrogen (flow rate ratio 2: 2: 1.5) is introduced into the plasma processing chamber 21 as a raw material gas, and the gas pressure is increased. Was adjusted to 0.5 Pa, high frequency power of 13.56 MHz that intermittently pulsates with a repetition frequency of 2 kHz and an oscillation duration of 100 μs was supplied to the high frequency antenna 24 to excite the discharge plasma. By applying a negative pulse voltage having a peak value of 12 kV and a pulse width of 5 μs to the aluminum material 11 in a state where this discharge plasma is excited for 15 minutes in synchronization with the pulse oscillation of the high frequency power, the conductive diamond-like A carbon layer 13 was formed. In this manner, a current collector material as the conductive member 101 of the present invention was produced.

  Further, in order to measure the resistivity of the conductive diamond-like carbon layer 13 obtained in Example 3, the same film formation conditions as those of the conductive diamond-like carbon layer 13 on a glass substrate having a size of 5 cm × 2 cm are used. Thus, a conductive diamond-like carbon layer was formed. As a result of measuring the resistivity of the obtained conductive diamond-like carbon layer by a four-terminal method (manufactured by Mitsubishi Chemical Analytech Co., Ltd., Loresta GP), the resistivity was about 40 mΩ · cm.

  In addition, an electrode active material layer 14 was formed on the current collector as the obtained conductive member 101 in the same manner as in Example 1, and an electrode 100 having a thickness of 45 μm was formed.

  The obtained electrode 100 was immersed in a 1% hydrofluoric acid solution. As a result, even after 15 minutes, neither gas generation due to corrosion of the conductive member 101 nor separation of the electrode active material layer 14 from the conductive member 101 was observed.

Example 4
Using the conductive member 101 obtained in Example 3, an electric double layer capacitor film cell was produced in the same manner as in Example 2.

(Comparative Example 1)
Aluminum material 11 (JIS 1085) having an aluminum content of 99.9% by mass and a thickness of 20 μm prepared in Example 1 was immersed in a 1% hydrofluoric acid solution. As a result, after 2 minutes, gas was generated due to corrosion of the aluminum material.

  In addition, an electrode active material layer was formed in the same manner as described above on one surface of an aluminum material 11 (JIS 1085) having an aluminum content of 99.9% by mass and a thickness of 20 μm prepared in Example 1. An electrode having a thickness of 45 μm was produced.

  The obtained electrode was immersed in a 1% hydrofluoric acid solution. As a result, when 2 minutes passed, gas due to corrosion of the aluminum material was generated, and when 5 minutes passed, peeling of the electrode active material layer from the aluminum material was observed.

(Comparative Example 2)
An electrode having a thickness of 45 μm was produced in the same manner as in Example 2 except that an etched aluminum foil (model number 50CK) manufactured by Nippon Electric Power Storage Co., Ltd. was used as the current collector.

  Using the obtained electrode, a film cell of an electric double layer capacitor was produced in the same manner as in Example 2.

(Comparative Example 3)
In Comparative Example 3, an aluminum material 11 (JIS 1085) having an aluminum content of 99.9% by mass and a thickness of 20 μm was prepared. An aluminum material 11 is provided on an aluminum frame (not shown) fixed to an insulating support (not shown), and a pair of inductively coupled high frequency is used as a workpiece 25 shown in FIG. The antenna 24 is mounted so as to face the substantially central portion. Next, the inside of the plasma processing chamber 21 was evacuated to a high vacuum of 10 −3 Pa or less. And the gas was fully discharged | emitted from the workpiece 25 by hold | maintaining the workpiece 25 at the temperature of 330-360 degreeC. Thereafter, a mixed gas of argon and hydrogen was introduced into the plasma processing chamber 21, the gas pressure was adjusted to a pressure of 0.5 Pa, and high frequency power of 700 W was supplied to the high frequency antenna 24 to excite the discharge plasma. . By applying a negative pulse voltage having a peak value of 8 kV, a repetition frequency of 2 kHz, and a pulse width of 5 μs to the aluminum material 11 as the workpiece 25 in a state where the discharge plasma is excited, ion bombardment for 30 minutes is performed. The surface was cleaned by

  Subsequently, a conductive diamond-like carbon layer 13 was formed on the aluminum material 11 as follows. The aluminum material 11 is maintained at a temperature of 330 to 360 ° C., and a mixed gas of methane, acetylene and nitrogen (flow rate ratio 2: 2: 1.5) is introduced into the plasma processing chamber 21 as a raw material gas, and the gas pressure is increased. Was adjusted to 0.5 Pa, high frequency power of 13.56 MHz that intermittently pulsates with a repetition frequency of 2 kHz and an oscillation duration of 100 μs was supplied to the high frequency antenna 24 to excite the discharge plasma. By applying a negative pulse voltage having a peak value of 12 kV and a pulse width of 5 μs to the aluminum material 11 for 10 minutes in synchronism with pulse oscillation of high frequency power in a state where the discharge plasma is excited, a conductive diamond-like A carbon layer 13 was formed. Thus, a current collector material as a conductive member in which the conductive diamond-like carbon layer 13 was formed on the surface of the aluminum material 11 was produced. This corresponds to a structure in which the passive layer 12 is not formed from the configuration of the conductive member of the present invention. Further, on the current collector as the obtained conductive member, an electrode active material layer 14 was formed in the same manner as in Example 1 to produce an electrode having a thickness of 45 μm.

  The obtained electrode was immersed in a 1% hydrofluoric acid solution. As a result, when 5 minutes passed, gas due to corrosion of the aluminum material was generated, and when 10 minutes passed, peeling of the electrode active material layer from the aluminum material was observed.

(Comparative Example 4)
Using the conductive member obtained in Comparative Example 3, an electric double layer capacitor film cell was produced in the same manner as in Example 2.

The AC impedance in the frequency region of 120 mHz to 20 kHz was measured at an applied voltage of 10 mV _{0-P on} each of the produced electric double layer capacitor film cells of Example 2, Example 4, Comparative Example 2 and Comparative Example 4. . The obtained result is shown in FIG. From FIG. 8, in the film cell of the electric double layer capacitor of Comparative Example 2, a semicircle of the electrode resistance component is generated, whereas in the film cell of the electric double layer capacitor of Example 2, the semicircle of the electrode resistance component is can not see. From this result, it can be said that the film cell of the electric double layer capacitor of Example 2 has a lower resistance than the film cell of the electric double layer capacitor of Comparative Example 2. Further, when Example 4 and Comparative Example 4 are compared with each other, the conductive diamond-like carbon layer is included and thus the resistance is low. In Example 4, the surface of the conductive aluminum nitride layer as the passive layer 12 is provided. Since the contact resistance between the two is reduced by directly bonding the conductive diamond-like carbon layer 13, the resistance is further reduced.

In addition, a charge / discharge test was performed in a voltage range of 1 to 2.5 V on each of the produced electric double layer capacitor film cells of Example 2, Example 4, Comparative Example 2, and Comparative Example 4. Assuming power application, discharging was performed at a current density of 50 mA / cm ² . The result is shown in FIG. From FIG. 9, it can be seen that the IR-drop of the film cell of the electric double layer capacitor of Example 2, Example 4 and Comparative Example 4 is much smaller than that of the film cell of the electric double layer capacitor of Comparative Example 2. From this result, it can be seen that the film cells of the electric double layer capacitors of Example 2, Example 4 and Comparative Example 4 have low resistance. Further, it can be seen from FIG. 9 that the discharge time of the electric double layer capacitor film cell of Example 2 is longer than that of the electric double layer capacitor film cell of Comparative Example 2. In addition, Table 1 below shows the result of calculating the electrical resistance value in each of the electric double layer capacitors of Example 2, Example 4, Comparative Example 2, and Comparative Example 4 from FIG.

  It should be considered that the embodiments and examples disclosed above are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the above embodiments and examples but by the scope of claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the scope of claims. .

  In a conductive member used as a material such as a current collector that constitutes an electrode of a secondary battery, a capacitor, or the like, peeling of the electrode active material can be suppressed and the resistance of the electrode can be reduced.

11: Aluminum material, 12: Passive layer, 13: Conductive diamond-like carbon layer, 14: Electrode active material layer, 15: Electrolytic solution, 16: Separator, 100: Electrode, 101: Conductive member.

Claims (12)

Aluminum material,
A passive layer formed from the surface of the aluminum material toward the inside and containing at least one of boron and nitrogen and aluminum;
A conductive diamond-like carbon layer formed on the surface of the passive layer;
A conductive member comprising:   The conductive member according to claim 1, wherein the passive layer has a thickness of 5 nm to 200 nm.   The conductive member according to claim 1, wherein a thickness of the conductive diamond-like carbon layer is 10 nm or more and 300 nm or less.   The conductive member according to any one of claims 1 to 3, wherein the conductive member is a current collector. The conductive member according to claim 4,
An electrode active material layer formed on the surface of the conductive diamond-like carbon layer in the conductive member;
With an electrode.   The electrode which consists of an electrically-conductive member of any one of Claim 1- Claim 3.   A secondary battery comprising the electrode according to claim 5.   A capacitor comprising the electrode according to claim 5. By injecting at least one of boron ions and nitrogen ions into the surface of the aluminum material while the aluminum material is heated in the space where the discharge plasma containing at least one of boron ions and nitrogen ions is generated Forming a passive layer containing at least one of boron and nitrogen and aluminum from the surface of the aluminum material toward the inside;
Conductive diamond that forms a conductive diamond-like carbon layer on the surface of the aluminum material on which the passive layer has been formed in a space in which discharge plasma containing carbon ions is generated while the aluminum material is heated. Like carbon layer formation process,
The manufacturing method of the electrically-conductive member provided with.   In the passive layer forming step, discharge plasma is formed in the vicinity of at least one surface of the aluminum material in a state where the aluminum material is disposed in the space and at least one of a boron compound gas and a nitrogen compound gas is introduced into the space. The method for producing a conductive member according to claim 9, further comprising: forming a passive layer from the surface of the aluminum material toward the inside by applying a negative bias voltage to the aluminum material. .   In the conductive diamond-like carbon layer forming step, the aluminum material is disposed in the space, and a carbon compound gas is introduced into the space to generate discharge plasma in the vicinity of at least one surface of the aluminum material, 11. The method according to claim 9, further comprising: forming the conductive diamond-like carbon layer on a surface of the aluminum material on which the passive layer is formed by applying a negative bias voltage to the aluminum material. A method for producing the conductive member according to claim 1. The manufacture of an electrode provided with the process of forming an electrode active material layer in the surface of the said electroconductive diamond-like carbon layer in the electrically-conductive member obtained by the manufacturing method of any one of Claim 9 to Claim 11 Method.