WO2017110693A1 - ガス拡散電極および燃料電池 - Google Patents
ガス拡散電極および燃料電池 Download PDFInfo
- Publication number
- WO2017110693A1 WO2017110693A1 PCT/JP2016/087627 JP2016087627W WO2017110693A1 WO 2017110693 A1 WO2017110693 A1 WO 2017110693A1 JP 2016087627 W JP2016087627 W JP 2016087627W WO 2017110693 A1 WO2017110693 A1 WO 2017110693A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- microporous layer
- gas diffusion
- diffusion electrode
- layer
- porous substrate
- Prior art date
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/8605—Porous electrodes
- H01M4/8626—Porous electrodes characterised by the form
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/8605—Porous electrodes
- H01M4/861—Porous electrodes with a gradient in the porosity
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/8647—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites
- H01M4/8657—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites layered
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/023—Porous and characterised by the material
- H01M8/0241—Composites
- H01M8/0245—Composites in the form of layered or coated products
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M2008/1095—Fuel cells with polymeric electrolytes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/88—Processes of manufacture
- H01M4/8803—Supports for the deposition of the catalytic active composition
- H01M4/8807—Gas diffusion layers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/88—Processes of manufacture
- H01M4/8878—Treatment steps after deposition of the catalytic active composition or after shaping of the electrode being free-standing body
- H01M4/8882—Heat treatment, e.g. drying, baking
- H01M4/8885—Sintering or firing
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/96—Carbon-based electrodes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Definitions
- the present invention relates to a gas diffusion electrode and a fuel cell.
- a fuel cell is a mechanism that electrically extracts energy generated when water is produced by reacting hydrogen and oxygen. Fuel cells are expected to be widely used as clean energy because they have high energy efficiency and only have water discharge. Among these, polymer electrolyte fuel cells are expected to be used as power sources for fuel cell vehicles and the like.
- An electrode used in a polymer electrolyte fuel cell is sandwiched between two separators in a polymer electrolyte fuel cell and disposed between them.
- Such an electrode has a structure comprising a catalyst layer formed on the surface of the polymer electrolyte membrane and a gas diffusion layer formed outside the catalyst layer on both surfaces of the polymer electrolyte membrane.
- a gas diffusion electrode is distributed as an individual member for forming a gas diffusion layer on the electrode.
- the performance required for the gas diffusion electrode includes, for example, gas diffusivity, conductivity for collecting electricity generated in the catalyst layer, and drainage for efficiently removing moisture generated on the surface of the catalyst layer. can give.
- a conductive porous substrate having both gas diffusibility and conductivity is used.
- carbon felt made of carbon fiber, carbon paper, carbon cloth, etc. are used as the conductive porous substrate.
- carbon paper is most preferable from the viewpoint of mechanical strength.
- a fuel cell is a system that electrically extracts energy generated when hydrogen and oxygen react to produce water
- the electrical load increases, that is, when the current taken out of the cell increases, a large amount of water ( Steam) is generated.
- this water vapor condenses into water droplets at low temperatures and closes the pores of the gas diffusion electrode, the amount of gas (oxygen or hydrogen) supplied to the catalyst layer decreases. When all the pores are finally closed, power generation stops (this phenomenon is called flooding).
- the gas diffusion electrode is required to be drainable.
- the water repellency is usually increased by using a gas diffusion electrode base material obtained by subjecting the conductive porous base material to water repellency treatment.
- a layer called a microporous layer is formed by applying a coating liquid in which conductive fine particles such as carbon black are dispersed on a conductive porous substrate that has been subjected to a water repellent treatment, followed by drying and sintering. (Also referred to as a layer).
- a fluororesin is preferably used.
- PTFE polytetrafluoroethylene
- FEP tetrafluoroethylene hexafluoropropylene copolymer
- These fluororesins are usually marketed in a dispersion state in which they are dispersed in an aqueous dispersion medium with a surfactant. Water-based coating is also preferable from the viewpoint of reducing environmental burden.
- Patent Documents 1 to 5 it has been difficult to achieve both flood resistance and dry-up resistance.
- applications that require high output such as being mounted on fuel cell vehicles, it has been difficult to obtain high performance in a wide temperature range.
- An object of the present invention is to overcome such drawbacks of the prior art and provide a gas diffusion electrode that has both dry-up resistance and flooding resistance and has good power generation performance in a wide temperature range.
- a gas diffusion electrode having a microporous layer on at least one surface of a conductive porous substrate, the microporous layer including a first microporous layer in contact with the conductive porous substrate, and the first microporous layer.
- a dense layer in contact with the porous layer, the thickness of the dense layer is 1 ⁇ m or more, and the pore size of the microporous layer disposed on at least one surface of the conductive porous substrate is 0.15 ⁇ m or more and 1 ⁇ m or less.
- the gas diffusion electrode has an average number density B of pores having a pore diameter of 0.15 ⁇ m or more and 1 ⁇ m or less of the dense layer of 1.3 A or more.
- the gas diffusion electrode of the present invention By using the gas diffusion electrode of the present invention, it is possible to provide a fuel cell having both dry-up resistance and flooding resistance and good power generation performance in a wide temperature range.
- positioning figure which shows another preferable aspect example of the manufacturing apparatus of the gas diffusion electrode of this invention. It is the schematic of the apparatus for measuring the gas diffusivity of an in-plane direction.
- An example of the number density distribution of pores having a pore diameter of 0.15 ⁇ m or more and 1 ⁇ m in the present invention An example which shows the number density distribution of the pore of 0.15 micrometer or more and 1 micrometer or less of the pore diameter in the thickness direction of the gas diffusion electrode of this invention.
- the gas diffusion electrode of the present invention is a gas diffusion electrode having a microporous layer on at least one surface of a conductive porous substrate, and the microporous layer includes a first microporous layer in contact with the conductive porous substrate and A dense layer in contact with the first microporous layer, the thickness of the dense layer is 1 ⁇ m or more, and the pore diameter of the microporous layer disposed on at least one side of the conductive porous substrate is 0.15 ⁇ m or more When the average number density of pores of 1 ⁇ m or less is A, the average number density B of pores of the dense layer having a pore diameter of 0.15 ⁇ m or more and 1 ⁇ m or less is 1.3 A or more.
- the gas diffusion electrode of the present invention has a microporous layer on at least one surface of the conductive porous substrate.
- the microporous layer has at least a first microporous layer in contact with the conductive porous substrate and a dense layer in contact with the first microporous layer.
- the conductive porous substrate will be described first.
- the gas diffusion electrode has a high gas diffusibility for diffusing the gas supplied from the separator to the catalyst, and a high drainage for discharging the water generated by the electrochemical reaction to the separator. And high conductivity to extract the generated current are required.
- a conductive porous base material which is a base material made of a porous body that has conductivity and usually has a pore diameter peak in a region of 10 ⁇ m to 100 ⁇ m, is used for the gas diffusion electrode.
- the pore diameter and distribution of the conductive porous substrate can be determined by measuring the pore diameter distribution with a mercury porosimeter.
- the conductive porous substrate include, for example, a porous substrate containing carbon fibers such as carbon fiber woven fabric, carbon fiber papermaking body, carbon fiber nonwoven fabric, carbon felt, carbon paper, and carbon cloth, It is preferable to use a porous metal substrate such as a bonded metal, a metal mesh, or an expanded metal. Among them, since the corrosion resistance is excellent, it is preferable to use a porous substrate such as carbon felt containing carbon fiber, carbon paper, carbon cloth, and moreover, a property of absorbing a dimensional change in the thickness direction of the electrolyte membrane, That is, since it is excellent in “spring property”, it is preferable to use a base material obtained by binding a carbon fiber papermaking body with a carbide, that is, carbon paper.
- a porous substrate containing carbon fibers such as carbon fiber woven fabric, carbon fiber papermaking body, carbon fiber nonwoven fabric, carbon felt, carbon paper, and carbon cloth
- a porous metal substrate such as a bonded metal, a metal mesh, or an expanded
- the porosity of the conductive porous substrate is preferably 80% or more, and more preferably 85% or more, in order to enhance the gas diffusibility of the gas diffusion electrode and enhance the power generation performance of the fuel cell as much as possible.
- the upper limit of the porosity is preferably 95% or less in order to easily maintain the structure of the conductive porous substrate.
- a cross section in the thickness direction is cut out with an ion milling device (manufactured by Hitachi High-Technologies Corporation, IM4000 type and equivalents thereof), and observed with a scanning electron microscope (SEM). It can be defined by binarizing the void portion and the non-void portion in contact with the cross section and setting the ratio of the area of the void portion to the entire area as the void ratio (%).
- the porosity of the conductive porous substrate may be measured directly using the conductive porous substrate, or may be measured using a gas diffusion electrode.
- the gas diffusibility of the gas diffusion electrode can be easily improved by reducing the thickness of the conductive porous substrate such as carbon paper.
- the thickness of the conductive porous substrate such as carbon paper is preferably 220 ⁇ m or less, more preferably 150 ⁇ m or less, and further preferably 120 ⁇ m or less.
- it is usually preferably 70 ⁇ m or more.
- the conductive porous base material is unwound in a long state and wound up. It is preferable to form a microporous layer continuously between the two.
- a conductive porous substrate that has been subjected to a water repellent treatment by applying a fluororesin is preferably used. Since the fluororesin acts as a water repellent, the conductive porous substrate used in the present invention preferably contains a water repellent such as a fluororesin.
- PTFE polytetrafluoroethylene
- FEP tetrafluoroethylene
- PFA perfluoroalkoxy fluororesin
- ETFA ethylene tetrafluoride ethylene copolymer
- PVDF polyvinylidene fluoride
- PVF polyvinyl fluoride
- the amount of the water repellent is not particularly limited, but about 0.1% by mass to 20% by mass is appropriate for 100% by mass of the entire conductive porous substrate. When the content is 0.1% by mass or more, sufficient water repellency is exhibited. By setting the content to 20% by mass or less, it is possible to easily secure pores serving as gas diffusion paths or drainage paths while exhibiting water repellency.
- the method for water repellent treatment of a conductive porous substrate is a method of immersing the conductive porous substrate in a dispersion containing a generally known water repellent, as well as by conducting die coating, spray coating, etc.
- An application technique for applying a water repellent to a porous porous substrate is also applicable.
- processing by a dry process such as sputtering of a fluororesin can also be applied.
- the conductive porous substrate has a microporous layer on at least one side.
- the microporous layer has at least a first microporous layer in contact with the conductive porous substrate and a dense layer in contact with the first microporous layer.
- the role of the microporous layer is as follows: (1) The catalyst is protected as a buffer material with the conductive porous substrate having irregularities, and (2) The rough surface of the conductive porous substrate is not transferred to the electrolyte membrane. And (3) an effect of preventing condensation of water vapor generated at the cathode.
- the microporous layer has a certain thickness in order to develop a retouching effect.
- the microporous layer includes at least a first microporous layer and a dense layer.
- the total thickness of the microporous layer is preferably greater than 10 ⁇ m and not greater than 60 ⁇ m in view of the roughness of the current conductive porous substrate. Note that the total thickness of the microporous layer refers to the first microporous layer when the microporous layer is formed of two layers of the first microporous layer 201 and the dense layer 202 as shown in FIG. The total thickness of the layer thickness 22 and the dense layer thickness 21, as shown in FIG.
- the microporous layer includes a first microporous layer 201, a dense layer 202, and a second microporous layer 203 3
- the thickness is the sum of the thickness 22 of the first microporous layer, the thickness 21 of the dense layer, and the thickness 23 of the second microporous layer.
- the total thickness of the microporous layer here refers to the total thickness of the microporous layer on one side of the conductive porous substrate on which the first microporous layer and the dense layer are arranged. Even when the microporous layer is disposed on both surfaces of the porous substrate, the microporous layer on only one surface of the conductive porous substrate on which the first microporous layer and the dense layer are disposed is targeted.
- the thickness of the gas diffusion electrode or the conductive porous substrate can be measured using a micrometer or the like while applying a load of 0.15 MPa to the substrate. Moreover, about the thickness of a microporous layer, the cross section of the thickness direction can be cut out with an ion milling device (Hitachi High-Technologies company make IM4000 type
- the average number density of pores having a pore diameter of 0.15 ⁇ m or more and 1 ⁇ m or less in the microporous layer is A
- the average number density of pores having a pore diameter of 0.15 ⁇ m or more and 1 ⁇ m or less is 1.3 A or more.
- a region having a thickness of 1 ⁇ m or more is defined as a dense layer.
- the presence of a dense layer containing a large number of pores in the above-mentioned pore size range makes it easy to achieve both gas diffusibility and drainage, and further laminates an electrolyte membrane with a catalyst layer and a gas diffusion electrode to heat melt.
- the electrolyte polymer contained in the catalyst layer can be easily prevented from diffusing into the entire microporous layer, and the performance of the catalyst layer can be easily maintained, so that high power generation performance can be easily obtained. be able to.
- the average number density B of pores of 0.15 ⁇ m to 1 ⁇ m in the pore diameter in the dense layer is preferably 1.5 / ⁇ m 2 or more, and more preferably 2.0 / ⁇ m 2 or more is preferable.
- the first microporous layer is less sparse than the dense layer.
- the average number density of pores having a pore diameter of 0.15 ⁇ m or more and 1 ⁇ m or less in the first microporous layer is preferably 2 / ⁇ m 2 or less, and more preferably 1.5 / ⁇ m 2. The following is good.
- the average number density of pores having a pore diameter of 1 ⁇ m or more is 0.05 / ⁇ m 2 or more. More preferably, 0.1 piece / ⁇ m 2 or more is preferable.
- a gas diffusion electrode having an electrically conductive porous substrate, at least a first microporous layer, and a dense layer is cut in the thickness direction using an ion milling device such as IM4000 manufactured by Hitachi High-Technologies Corporation.
- the cross section in the thickness direction is observed with a scanning electron microscope (SEM).
- SEM scanning electron microscope
- the cross-sectional SEM image was binarized to extract pores, and pores having a pore area equal to or larger than a circle having a diameter of 0.15 ⁇ m were defined as pores having a pore diameter of 0.15 ⁇ m or more.
- a pore having a pore area of 1 ⁇ m or less in diameter is defined as a pore having a pore diameter of 1 ⁇ m or less. Measure the number of pores that fall within these ranges, measure the position of the pores in the thickness direction from the surface of the microporous layer, and divide by the cross-sectional area of the microporous layer in the cross-sectional SEM image As a result, an average number density A of pores having a pore diameter of 0.15 ⁇ m or more and 1 ⁇ m or less in the entire microporous layer was obtained.
- 1 of the average number density A is obtained.
- a region having a thickness of 3 times or more and a thickness of 1 ⁇ m or more was defined as a dense layer.
- the thickness of the dense layer is preferably 1 ⁇ m or more, more preferably 2 ⁇ m or more, and further preferably 3 ⁇ m or more in order to suppress diffusion of the electrolyte polymer in the catalyst layer.
- the dense layer is preferably 10 ⁇ m or less, more preferably 8 ⁇ m or less, and even more preferably 6 ⁇ m or less.
- the microporous layer is not particularly limited as long as it is at least two layers of the first microporous layer in contact with the conductive porous substrate and the dense layer in contact with the first microporous layer, and the second layer in contact with the dense layer.
- the microporous layer may be provided on the surface.
- the microporous layer preferably has a second microporous layer in contact with the surface side of the dense layer. That is, the gas diffusion electrode of the present invention may be in contact with the dense layer and have the second microporous layer on the surface side opposite to the first microporous layer.
- the second microporous layer when the electrolyte membrane with a catalyst layer and the gas diffusion electrode are laminated and thermally fused, a uniform pressure can be applied by a buffering action to increase the adhesion.
- the gas diffusion electrode of the present invention has a dense layer having a pore diameter of 0.15 ⁇ m or more and 1 ⁇ m or less, where C is the average number density of pores having a pore diameter of 0.15 ⁇ m or more and 1 ⁇ m or less in the second microporous layer.
- the average number density B of the pores is preferably 1.3C or more. Since the second microporous layer has larger pores than the dense layer, when the electrolyte membrane with a catalyst layer and the gas diffusion electrode are laminated and thermally fused, the electrolyte polymer contained in the catalyst layer is the second microporous layer. A small amount can be diffused into the porous layer to obtain good adhesion between the microporous layer and the catalyst layer.
- the thickness of the second microporous layer is preferably 10 ⁇ m or less, more preferably 8 ⁇ m or less, in order to suppress a large amount of diffusion. Preferably it is 6 ⁇ m or less.
- the adhesive force is increased by applying uniform pressure when the electrolyte membrane with a catalyst layer and the gas diffusion electrode are laminated and thermally fused. Can do.
- the dense layer preferably has a thickness of 1 ⁇ m to 10 ⁇ m
- the second microporous layer preferably has a thickness of 1 ⁇ m to 10 ⁇ m.
- the portion of the microporous layer that is in contact with the conductive porous substrate side of the dense layer is defined as the first microporous layer.
- the thickness of the first microporous layer it is preferable that the total thickness of the microporous layer is larger than 10 ⁇ m as described above in order to express the effect of retouching the roughness of the conductive porous substrate. More preferably, the thickness of the first microporous layer alone is 10 ⁇ m or more. However, the thickness of the first microporous layer is preferably less than 50 ⁇ m because it is necessary to easily ensure gas diffusibility even when the microporous layer is laminated thereon.
- the primary particle size of the conductive fine particles used for the first microporous layer is preferably equal to or larger than the primary particle size of the conductive fine particles used for the second microporous layer. This is because the dense layer can be made denser.
- the conductive fine particles contained in the first microporous layer preferably have a primary particle size in the range of 0.040 ⁇ m to 0.060 ⁇ m, and more preferably in the range of 0.045 ⁇ m to 0.060 ⁇ m.
- the conductive fine particles contained in the second microporous layer preferably have a primary particle diameter in the range of 0.015 ⁇ m to 0.040 ⁇ m, and more preferably in the range of 0.020 ⁇ m to 0.037 ⁇ m. preferable.
- the first microporous layer includes conductive fine particles having a primary particle diameter of 0.040 ⁇ m or more and 0.060 ⁇ m or less
- the second microporous layer has a primary particle diameter of 0.015 ⁇ m or more. More preferably, it contains conductive fine particles of 0.040 ⁇ m or less.
- the dense layer in order to control the average number density of pores having a pore diameter of 0.15 ⁇ m or more and 1 ⁇ m or less to 1.3 A or more, conductive fine particles having different primary particle diameters, secondary particle diameters, and structure indices described later are used.
- a method of forming a dense layer utilizing the fact that the conductive fine particles of the first microporous layer and the second microporous layer are mixed together at the time of coating is preferable. This is preferable because there is a cost reduction effect due to the reduction of the process.
- the dense layer is composed of conductive fine particles having a primary particle diameter of 0.040 ⁇ m or more and 0.060 ⁇ m or less, and conductive fine particles having a primary particle diameter of 0.015 ⁇ m or more and 0.040 ⁇ m or less. It is preferable to include.
- the microporous layer is a layer containing conductive fine particles such as carbon black, carbon nanotube, carbon nanofiber, chopped fiber of carbon fiber, graphene, and graphite.
- conductive fine particles carbon black is preferably used from the viewpoint of low cost and safety and stability of product quality.
- the dense layer, the first microporous layer, and the second microporous layer all contain carbon black.
- the carbon black contained in the dense layer, the first microporous layer, and the second microporous layer has a primary particle size of 0.1 ⁇ m or less, and is therefore suitable in the present invention, and has few impurities.
- Acetylene black is preferably used because it is difficult to reduce the activity of the catalyst.
- ash is mentioned as a standard of the impurity content of carbon black, but it is preferable to use carbon black having an ash content of 0.1% by mass or less.
- the ash content in the carbon black is preferably as small as possible, and carbon black having an ash content of 0% by mass, that is, carbon black containing no ash is particularly preferable.
- the microporous layer has characteristics such as conductivity, gas diffusivity, water drainage, moisture retention, and thermal conductivity, as well as strong acid resistance on the anode side inside the fuel cell and oxidation resistance on the cathode side. Sex is required. Therefore, the microporous layer preferably contains a water repellent such as a fluororesin in addition to the conductive fine particles.
- the microporous layer preferably contains a water repellent, and the water repellent has a melting point of 200 ° C. or higher and 320 ° C. or lower.
- the water repellent has a melting point of 200 ° C. or higher and 320 ° C. or lower.
- the melt viscosity at the time of sintering is reduced, and the microporous layer can be uniformly repellent by spreading in the microporous layer. .
- the sintering temperature can be suppressed and the cost can be reduced.
- fluororesin contained in the microporous layer examples include PTFE, FEP, PFA, ETFA, and the like, similarly to the fluororesin that is suitably used when the conductive porous substrate is water-repellent.
- PTFE, or FEP and PFA are preferred because of their particularly high water repellency.
- FEP or PFA is desirable as the water repellent resin having a low melting point.
- the content of the water repellent contained in the microporous layer is preferably 10% by mass or more and 50% by mass or less when the mass of the entire microporous layer is 100% by mass.
- the content in such a range, good water repellency can be obtained.
- the water repellent is 50% by mass or less, formation of pores in the microporous layer and low electrical resistance can be realized.
- the water repellent is thermally decomposed at 400 degrees or more and disappears at 500 degrees. For this reason, the content of the water repellent contained in the microporous layer can be measured by regarding the weight loss when the microporous layer is heated to the atmosphere at 500 degrees as the water repellent amount.
- a coating liquid for forming the microporous layer on the conductive porous substrate that is, a coating liquid for forming a microporous layer (hereinafter referred to as a microporous layer coating liquid).
- the microporous layer coating liquid usually comprises the above-described conductive fine particles and a dispersion medium such as water or alcohol. In many cases, a surfactant or the like is blended as a dispersant for dispersing the conductive fine particles.
- the water repellent is included in the microporous layer, it is preferable that the water repellent is included in advance in the microporous layer coating liquid.
- the substrate film is once coated on a substrate such as a PET film, and the surface of the microporous layer is pressure-bonded on the conductive porous substrate.
- a transfer method for peeling is also known.
- the manufacturing process is complicated, and sufficient adhesion may not be obtained between the conductive porous substrate and the microporous layer. Therefore, as a method for forming the microporous layer, a method of applying the microporous layer coating liquid to the conductive porous substrate is preferable. Details of the method will be described later.
- the concentration of the conductive fine particles in the microporous layer coating liquid is preferably 5% by mass or more, more preferably 10% by mass or more from the viewpoint of productivity. If the viscosity, dispersion stability of the conductive fine particles, coating properties of the coating liquid are suitable, there is no upper limit on the concentration, but in practice the concentration of the conductive fine particles in the microporous layer coating liquid is 50% by mass or less. By doing so, the applicability of the coating liquid can be secured.
- acetylene black is used as the conductive fine particles, the inventors have studied that, in the case of an aqueous coating solution, the concentration of acetylene black in the microporous layer coating solution is set to 25% by mass or less.
- the coating liquid of the microporous layer has a stable viscosity, and the coating property of the coating liquid can be ensured. Further, by adding a dispersant or a thickener to the microporous layer coating solution, the dispersion stability of the conductive fine particles and the coating property of the coating solution can be obtained.
- microporous layer coating liquid to the conductive porous substrate can be performed using various commercially available coating apparatuses.
- As the coating method screen printing, rotary screen printing, spray spraying, intaglio printing, gravure printing, die coater coating, bar coater coating, blade coater coating, roll knife coater coating, etc. can be used. Since the amount of coating can be quantified regardless of the surface roughness, coating with a die coater is preferable.
- coating with a blade coater or a roll knife coater is preferably used.
- the coating methods exemplified above are only for illustrative purposes and are not necessarily limited to these.
- the dispersion medium of the microporous layer coating liquid (water in the case of an aqueous system) is removed by drying.
- the drying temperature after coating is preferably from room temperature (around 20 ° C.) to 150 ° C. or less, more preferably from 60 ° C. to 120 ° C.
- the dispersion medium (for example, water) may be dried all at once in the subsequent sintering step.
- sintering may be performed for the purpose of removing the surfactant used in the microporous layer coating solution and for binding the conductive fine particles by dissolving the water repellent once. It is common.
- the sintering temperature is preferably 250 ° C. or more and 400 ° C. or less, although it depends on the boiling point or decomposition temperature of the added surfactant. If the sintering temperature is less than 250 ° C., the removal of the surfactant cannot be sufficiently achieved, or it takes an enormous amount of time to completely remove the surfactant, and if it exceeds 400 ° C., the water repellent may be decomposed. is there.
- the sintering time is as short as possible from the viewpoint of productivity, preferably within 20 minutes, more preferably within 10 minutes, and even more preferably within 5 minutes. Steam and decomposition products are generated abruptly, and there is a risk of ignition if performed in the atmosphere.
- the optimum temperature and time are selected in view of the melting point or decomposition temperature of the water repellent and the decomposition temperature of the surfactant.
- the drying may be performed after application of the first microporous layer coating liquid or after application of the surface microporous layer coating liquid. Sintering is preferably performed in a lump after application of the first microporous layer coating liquid and application / drying of the surface microporous layer coating liquid.
- the conductive particles of the first microporous layer are unbound, Mixing with the conductive fine particles of the microporous layer coating liquid can be formed, and a good dense layer can be formed.
- the coating liquid is formed in the pores of the conductive porous substrate as shown in FIGS. May penetrate and form a microporous layer soak 204 into the conductive porous substrate. Therefore, the thickness of each microporous layer in the present invention is evaluated only by the thickness of the portion existing outside the conductive porous substrate, excluding the soaked portion.
- the dense layer 202 and the second microporous layer 203 of the present invention are a coating liquid for forming a microporous layer on the outer surface of the first microporous layer as viewed from the conductive porous substrate side (hereinafter, It is formed by applying a surface microporous layer coating liquid).
- the surface microporous layer coating liquid is applied to the surface of the first microporous layer, and the surface microporous layer coating liquid is the first.
- a microporous layer and a mixed layer are formed, and a dense layer is formed on the surface.
- the second microporous layer can be formed on the surface of the dense layer by applying a larger amount of the surface microporous layer coating liquid.
- the control of the pore size of the first microporous layer is performed by selecting the type of conductive fine particles to be blended in the first microporous layer coating liquid, adjusting the degree of dispersion, and controlling the particle size and shape of the conductive fine particles. It is possible by selecting appropriately.
- As the conductive fine particles it is preferable to use carbon black because it is inexpensive and easily available, and the reliability of safety is high.
- the carbon black particles used in the first microporous layer form aggregates (so-called structures), and the carbon black is two-dimensional or three-dimensional. It is preferable to take a daisy chain structure. Thereby, the continuous space
- the carbon black in the first microporous layer preferably has a structure index of 3.0 or more.
- the structure index is obtained by dividing the value of the DBP oil absorption (cc / 100 g) of carbon black by the value of the BET specific surface area (m 2 / g). The larger this value is, the wider the branching structure of the carbon black agglomeration becomes, and it becomes easier to form large pores inside the coating film.
- the structure index is too large, cracks may occur between the carbon black aggregates, so the upper limit of the structure index of carbon black in the first microporous layer may be about 4.5. preferable.
- the gas diffusion electrode of the present invention has good power generation performance at high temperatures. Furthermore, in order to improve the power generation performance at a low temperature of 40 ° C. or lower, the gas diffusion electrode of the present invention preferably has a gas diffusion property in the thickness direction of 30% or more.
- the gas diffusivity in the thickness direction is more preferably 32% or more. The higher the gas diffusibility in the thickness direction, the better.
- the gas diffusion electrode of the present invention preferably has an in-plane gas diffusibility of 25 cc / min or more.
- the gas diffusivity in the in-plane direction is more preferably 50 cc / min or more.
- the gas diffusibility in the in-plane direction is measured at a pressure difference of 5 kPa as a basic measurement condition using a gas diffusion electrode, as will be described later. However, it cannot be measured if the measurement limit exceeds 190 cc / min.
- the practical upper limit is about 190 cc / min at 3 kPa, and if there is a permeability exceeding this, the thickness of the gas diffusion electrode is too large and the gas diffusivity in the thickness direction decreases, or the porosity When the gas diffusion layer is incorporated as a gas diffusion layer in a fuel cell, it is difficult to maintain the structure as the gas diffusion layer.
- the first microporous layer coating liquid is applied to the surface of the conductive porous substrate, and the surface microporous layer coating liquid is applied thereon, and the thickness of the second microporous layer is 10 ⁇ m or less. It is preferable to apply as described above. Here, a plurality of the second microporous layers can be formed. In order to apply such a thin film uniformly, after the first microporous layer coating solution is applied on the conductive porous substrate, the surface microporous layer coating solution is continuously applied without drying. It is also effective to apply Wet on Wet multilayer technology.
- the surface of the conductive porous substrate is generally rough, and the unevenness may be as close as 10 ⁇ m.
- the second microporous layer is preferably a thin film having a thickness of 10 ⁇ m or less, it is preferable that the viscosity of the surface microporous layer coating liquid is lowered to some extent.
- the first microporous layer coating liquid and the surface microporous layer coating liquid are overlapped and then dried together to uniformly distribute the dense layer and the second microporous layer on the surface of the first microporous layer.
- a porous thin film can also be formed.
- the first microporous layer coating solution is applied by a die coater, and the surface microporous layer coating solution is also applied by a die coater, and the first microporous layer coating solution is applied.
- a method in which various types of roll coaters are used to apply a surface microporous layer coating liquid using a die coater a first microporous layer coating liquid is applied using a roll knife coater, and a surface microporous layer coating liquid is applied to a die coater.
- the first microporous layer coating solution is applied with a lip coater
- the surface microporous layer coating solution is applied with a die coater
- the slide die coater is used before applying to the substrate.
- a method in which the microporous layer coating liquid 1 and the surface microporous layer coating liquid are superposed can be applied.
- the application method of the above die coater and roll knife coater is described in many existing documents such as “All about Converting” (edited by Processing Technology Research Group).
- the die coater is a type in which a pre-weighed coating solution is applied onto a substrate via a die for uniformly distributing in the width direction.
- the roll knife coater is a coating that smoothens the coating surface regardless of the unevenness of the substrate by scraping off the thickly thick coating liquid with a roll knife set at a certain height in the same way as the knife coater. It is a method.
- a surface layer such as the second microporous layer is formed as uniformly as possible on a thin film of 1 ⁇ m or more and 10 ⁇ m or less. Further, it is desirable that the adhesion between the electrolyte membrane coated with the catalyst on both sides and the gas diffusion electrode (the contact area between the catalyst layer surface and the microporous layer surface of the gas diffusion electrode) be as large as possible. For this purpose, it is desirable to make the surface of the microporous layer of the gas diffusion electrode as smooth as possible.
- GDE method a method of applying catalyst ink to the gas diffusion electrode side is generally known
- the catalyst ink in order to uniformly apply the catalyst ink, it is desirable to keep the surface of the microporous layer of the gas diffusion electrode as smooth as possible.
- the first microporous layer coating solution is applied with a roll knife coater, etc., and the surface roughness is temporarily increased with a die coater. When a coating liquid is applied, higher smoothness is obtained.
- the surface roughness Ra is used as an index of smoothness.
- the surface roughness of the microporous layer is preferably 6 ⁇ m or less.
- the dense layer or the second microporous layer is on the surface of the microporous layer. That is, the value of the surface roughness Ra (arithmetic mean roughness) of the dense layer or the second microporous layer on the surface of the microporous layer is preferably 6 ⁇ m or less.
- the surface roughness is more preferably 4 ⁇ m or less.
- Adhesion with a catalyst layer can be improved by Ra being 6 micrometers or less. Further, considering the case where the catalyst ink is applied to the surface of the microporous layer, the lower limit of the surface roughness Ra is considered to be about 0.1 ⁇ m.
- ⁇ Various surface roughness meters can be applied to the measurement of surface roughness. Since the microporous layer is relatively fragile, it is preferable to use a non-contact type measuring instrument.
- An example of a non-contact type measuring instrument is a laser microscope VX-100 manufactured by Keyence Corporation.
- a manufacturing apparatus suitable for manufacturing the gas diffusion electrode of the present invention includes an unwinder, a first coater, a second coater, a dryer, and a winder.
- the unwinding machine is used for unwinding a long conductive porous substrate wound in a roll shape.
- the first applicator is used to apply the first microporous layer coating solution to the conductive porous substrate unwound by the unwinder.
- the second applicator is used to apply the surface microporous layer coating solution to the conductive porous substrate.
- the conductive porous substrate is coated with the surface microporous layer coating liquid in a state where the first microporous layer coating liquid is applied and not substantially dried.
- the second applicator is disposed on the same surface side as the substrate surface on which the first applicator is disposed.
- the dryer is used to dry the conductive porous substrate on which the first microporous layer coating liquid and the surface microporous layer coating liquid are applied.
- a winder is used in order to wind up the obtained gas diffusion electrode.
- 3 and 4 illustrate a particularly preferable manufacturing apparatus according to the present invention.
- the long conductive porous substrate 1 is unwound from the unwinder 2 and conveyed while being appropriately supported by a guide roll (non-driven) 3.
- a certain first die coater 4 applies the first microporous layer coating solution to one side of the conductive porous substrate.
- the first microporous layer coating liquid is usually supplied from the coating liquid tank 12 to the die coater by the liquid feeding pump 13.
- the filter 14 is used for filtration.
- the surface microporous layer coating liquid is formed by the second die coater 5, which is a second coating machine, installed on the same substrate surface side as the first die coater 4.
- the gas diffusion electrode is wound up by a winder (drive) 9.
- the surface microporous layer coating liquid is also usually supplied from the coating liquid tank 12 to the die coater by the liquid feed pump 13.
- the filter 14 is used for filtration.
- the back roll 6 may be used when the microporous layer coating liquid is applied by the die coater, or the roll unrolled from the unwinder (for interleaf paper) 11 is used for protecting the coated surface during winding.
- the paper 10 may be wound together with the product.
- a roll knife coater 40 is installed in place of the first die coater 4 in FIG.
- the substrate is conveyed while supplying the coating material to the liquid dam 42, and the coating material is scraped off with the knife roll 41 so that a desired coating amount is obtained.
- drying of those several layers can be simplified, and a dryer can be simplified.
- the productivity is high, and the loss can be reduced even when the substrate is broken.
- the fuel cell of the present invention includes the gas diffusion electrode of the present invention.
- the fuel cell of the present invention can provide a fuel cell exhibiting high power generation performance in a wide range from high temperature to low temperature. Therefore, for example, the output of the fuel cell vehicle is improved, and a long cruising distance can be obtained by reducing the high driving force and the supplied fuel gas.
- the fuel cell of the present invention is formed by, for example, pressing the catalyst layer and the gas diffusion electrode so that the catalyst layer and the gas diffusion electrode are in contact with both sides of the electrolyte membrane provided with the catalyst layer on both sides, and further assembling the unit cell by incorporating a member such as a separator. Obtainable. At that time, the second microporous layer may be assembled so as to be in contact with the catalyst layer.
- the gas diffusion electrode of the present invention is suitably used for a fuel cell, in particular, a polymer electrolyte fuel cell used as a power source for a fuel cell vehicle or the like.
- Conductive porous substrate A carbon paper having a thickness of 150 ⁇ m and a porosity of 85% was prepared as follows.
- Polyacrylonitrile-based carbon fiber “Torayca” (registered trademark) T300-6K (average single fiber diameter: 7 ⁇ m, number of single fibers: 6,000) manufactured by Toray Industries, Inc. was cut to a length of 12 mm.
- paper is continuously made as a paper making medium together with pulp, and is further immersed in a 10% by weight aqueous solution of polyvinyl alcohol and dried to make a roll.
- a long carbon fiber paper of / m 2 was obtained.
- the amount of added pulp was 40 parts by mass and the amount of polyvinyl alcohol attached was 20 parts by mass with respect to 100 parts by mass of carbon fiber paper.
- a dispersion in which flaky graphite (average particle size: 5 ⁇ m), phenol resin and methanol were mixed at a mass ratio of 5:10:85 was prepared.
- the carbon fiber paper is continuously impregnated with the dispersion so that the resin component (phenol resin + flaky graphite) is 130 parts by mass with respect to 100 parts by mass of the short carbon fibers, and the temperature is 100 ° C.
- the product After passing through a resin impregnation step of drying for a minute, the product was wound into a roll to obtain a resin-impregnated carbon fiber paper.
- the phenol resin a mixture of a resol type phenol resin and a novolac type phenol resin at a mass ratio of 1: 1 was used.
- the carbon fiber paper that has been subjected to compression treatment is introduced into a heating furnace maintained in a nitrogen gas atmosphere as a precursor fiber sheet, and after undergoing a carbonization step of firing at a maximum temperature of 2400 ° C., the carbon paper is wound into a roll to obtain carbon paper It was.
- the obtained carbon paper had a density of 0.25 g / cm 3 and a porosity of 85%.
- the thickness is 180 ⁇ m and the porosity is 85%, in the same manner as the carbon paper having a thickness of 150 ⁇ m and a porosity of 85%, except that the weight of the carbon fiber and the pressure during the compression treatment are adjusted so that the thickness after carbonization becomes 180 ⁇ m. Obtained carbon paper.
- carbon fiber weight per unit area and the pressure during compression treatment were adjusted to obtain carbon paper having a carbonized thickness of 250 ⁇ m.
- Carbon blacks (1-4) Carbon black 1: primary particle size: 0.052 ⁇ m, DBP oil absorption 140 cc / 100 g, BET specific surface area 41 m 2 / g, structure index 3.4 Carbon black 2: primary particle size: 0.045 ⁇ m, DBP oil absorption 125 cc / 100 g, BET specific surface area 41 m 2 / g, structure index 3.0 Carbon black 3: primary particle size: 0.032 ⁇ m, DBP oil absorption 175 cc / 100 g, BET specific surface area 67 m 2 / g, structure index 2.6 Carbon black 4: primary particle size: 0.035 ⁇ m, DBP oil absorption 174 cc / 100 g, BET specific surface area 254 m 2 / g, structure index 0.69
- C Water repellent “Neofluon” (registered trademark) FEP dispersion ND-110 (FEP resin, manufactured by Daikin Industries, Ltd.).
- ⁇ Measurement of thickness of substrate and microporous layer The thickness of the base material (gas diffusion electrode and conductive porous base material) was measured using a digital thickness meter “Digimicro” manufactured by Nikon Corporation. Measurement was performed while applying a load of 0.15 MPa to the substrate.
- the thickness of the microporous layer was measured by subtracting the thickness of the conductive porous substrate from the thickness of the gas diffusion electrode when confirming the coating thickness when applying the microporous layer coating liquid to the substrate. . At this time, the thickness of the microporous layer immersed in the conductive porous substrate is not included.
- the cross section of the thickness direction of a gas diffusion electrode was created and evaluated.
- an ion milling apparatus IM4000 manufactured by Hitachi High-Technologies Corporation was used.
- S-4800 manufactured by Hitachi, Ltd. as a scanning electron microscope, the created cross-section was magnified 2000 times to photograph an image, and pore analysis was performed using “ImageJ” of image analysis software.
- FIG. 1st microporous layer, the dense layer, and the 2nd microporous layer was created and evaluated.
- FIG. 6 shows a schematic diagram of the distribution of Pixel [pieces] of the luminance corresponding to the vertical axis, with the luminance B of only the microporous layer in the cross-sectional image in the thickness direction on the horizontal axis.
- the threshold value for binarization was obtained by particle analysis using the inflection point 32 in the middle of the shoulder 33 on the side where the luminance is reduced from the local maximum point 31 as a threshold value, and the portion having a luminance lower than the threshold value as a pore.
- the pore diameter is 0.15 ⁇ m or more, gas diffusibility is improved, and when the pore diameter is 1 ⁇ m or less, retention of water is suppressed and drainage performance is improved.
- a fine layer was determined by extracting pores having an area corresponding to the pore diameter of 0.15 ⁇ m or more and 1 ⁇ m or less, and determining the average number density and the number density in the thickness direction of the entire microporous layer. Subsequently, the microporous layer closer to the conductive porous substrate than the dense layer was determined as the first microporous layer, and the microporous layer closer to the surface than the dense layer was determined as the second microporous layer. The thicknesses of the first microporous layer, the dense layer, and the second microporous layer thus determined were determined. An example is shown in FIG.
- the depth D [ ⁇ m] from the surface was taken as the horizontal axis and the pore number density P [pieces / ⁇ m 2 ] was taken as the vertical axis.
- the outermost surface of the microporous layer was approximated by a straight line, the line was defined as a surface 205 having a depth of 0 ⁇ m, and the direction perpendicular to the line was defined as the depth in the thickness direction.
- the average value of the pore number density P is defined as the average number density A207 of the pores of the microporous layer, the value of the pore number density P that is 1.3 times the value is 1.3 A.
- the value 206 is as follows.
- the first microporous layer, the dense layer, and the second microporous layer are taken out from the microporous layer of the gas diffusion electrode to be measured, heat-treated in the atmosphere at 500 ° C. for one hour, and then the conductivity contained in each layer.
- the fine particles were magnified 200,000 times using an electron microscope, the diameter of 100 randomly selected primary particles was measured, and the average value was taken as the average of the primary particles in each layer.
- ⁇ Surface roughness measurement> For the surface of the microporous layer of the gas diffusion electrode to be measured, an arithmetic average is obtained by measuring the roughness in the range of 5 mm square with 10 times the objective lens and no cut-off using a Keyence laser microscope VK-X100. The roughness Ra was determined. This was repeated 10 times at different measurement locations, and the average value was taken as the surface roughness value.
- ⁇ Gas diffusivity in the thickness direction> Using a water vapor gas water vapor permeation diffusion evaluation apparatus (MVDP-200C) manufactured by Seika Sangyo Co., Ltd., the gas whose diffusivity is to be measured is flowed to one side (primary side) of the gas diffusion electrode, and the other side ( Flow nitrogen gas to the secondary side.
- the differential pressure between the primary side and the secondary side is controlled in the vicinity of 0 Pa (0 ⁇ 3 Pa) (that is, there is almost no gas flow due to the pressure difference, and the gas movement phenomenon occurs only by molecular diffusion).
- the gas concentration when the equilibrium was reached was measured with this gas concentration meter, and this value (%) was used as an index of gas diffusivity in the thickness direction.
- a water vapor gas water vapor permeation diffusion evaluation apparatus (MVDP-200C) manufactured by Seika Sangyo Co., Ltd. was used.
- MVDP-200C water vapor gas water vapor permeation diffusion evaluation apparatus
- the valve A (303) was first opened and the valve B (305) was closed, and the nitrogen gas 313 was allowed to flow into the primary side piping A (302).
- the gas diffusion electrode sample (308) was set on the sealing material (312) between the gas chamber A (307) and the gas chamber B (309).
- valve A (303) was closed and the valve B (305) was opened so that nitrogen gas could flow through the pipe B (306).
- the nitrogen gas flowing into the gas chamber A (307) moves to the gas chamber B (309) through the gap of the gas diffusion electrode sample (308), passes through the pipe C (310), and further flows into the gas flow meter (311). And released into the atmosphere.
- the gas flow rate (cc / min) flowing through the gas flow meter (311) at this time was measured, and this value was defined as gas diffusivity in the in-plane direction.
- the measuring method of the melting point of the water repellent of the microporous layer was performed by differential scanning calorimetry. Only the microporous layer was collected from the gas diffusion electrode by tweezers.
- the apparatus was DSC6220 manufactured by Seiko Instruments Inc. (SII), and the temperature was changed from 30 ° C. to 400 ° C. in nitrogen at a temperature rising rate of 2 ° C./min. The endothermic peak at that time was observed, and the endothermic peak at a temperature of 150 ° C. or higher was defined as the melting point.
- the obtained gas diffusion electrode is an electrolyte membrane / catalyst layer integrated product (Nippon Gore's electrolyte membrane “Gore Select” (registered trademark) and Gore Japan made catalyst layer “PRIMEA” (registered trademark) on both sides)
- the membrane electrode assembly (MEA) was produced by sandwiching the catalyst layer and the microporous layer on both sides of each other and hot pressing at a pressure of 2 MPa at 110 ° C. for 20 minutes. This membrane electrode assembly is incorporated into a single cell for a fuel cell.
- the cell temperature is 40 ° C.
- the fuel utilization efficiency is 70%
- the air utilization efficiency is 40%
- the hydrogen on the anode side and the air on the cathode side are 75 ° C.
- Example 1 A water repellent dispersed in water so that the concentration of fluororesin becomes 2% by mass while transporting carbon paper having a thickness of 150 ⁇ m and a porosity of 85%, which is wound up in a roll shape, using a rewind-type transport device Water repellent treatment was performed by dipping in a dipping tank filled with the dispersion. It dried with the dryer set to 100 degreeC, and wound up with the winder, and obtained the electroconductive porous base material which carried out the water-repellent process. As the water repellent dispersion, FEP dispersion ND-110 diluted with water so that the FEP concentration was 2% by mass was used.
- conveyance provided with an unwinder 2, a guide roll (non-drive) 3, a back roll 6, an unwinder (for interleaf) 11, and a winder (drive) 9.
- a winding type continuous coater provided with two die coaters, a first die coater 4 and a second die coater 5, a dryer 7 and a sintering machine 8, was prepared in the apparatus.
- a raw material obtained by winding carbon paper having a thickness of 150 ⁇ m and a porosity of 85% in a roll shape was set in the unwinding machine 2.
- the raw material was conveyed by driving rolls installed in the unwinding unit, the winding unit, and the coater unit.
- the first microporous layer coating solution was applied using the first die coater 4, and then the surface microporous layer coating solution was continuously applied by the second die coater 5.
- moisture was dried with hot air at 100 ° C.
- the sintering machine 8 set to 350 degreeC after performing sintering for 10 minutes, it wound up with the winding machine (drive) 9.
- the microporous layer coating solution was prepared as follows.
- First microporous layer coating solution 15 parts by mass of carbon black 1, 5 parts by mass of FEP dispersion (“Neofluon” (registered trademark) ND-110), 15 parts by mass of surfactant (“TRITON” (registered trademark) X-100), 65 masses of purified water The parts were kneaded with a planetary mixer to prepare a coating solution.
- Surface microporous layer coating solution 5 parts by weight of carbon black 3, 2 parts by weight of FEP dispersion (“Neofluon” (registered trademark) ND-110), 7 parts by weight of surfactant (“TRITON” (registered trademark) X-100), 86 parts by weight of purified water The parts were kneaded with a planetary mixer to prepare a coating solution.
- the basis weight of the microporous layer after sintering was adjusted to 16 g / m 2 .
- the thickness of the first microporous layer was 22 ⁇ m.
- the dense layer was prepared to be 2 ⁇ m and the thickness of the second microporous layer was adjusted to 3 ⁇ m.
- the gas diffusion electrode prepared as described above was thermocompression bonded so that the microporous layer and the catalyst layer were in contact with both sides of the electrolyte membrane provided with the catalyst layer on both sides, and incorporated into a single cell of the fuel cell.
- the power generation performance (limit current density) was evaluated at each temperature of 40 ° C., 70 ° C., and 90 ° C.
- Tables 1 to 5 include other physical property values.
- Example 2 A gas diffusion electrode was obtained in the same manner as in Example 1 except that the carbon black contained in the first microporous layer coating liquid was changed to carbon black 2 in Example 1.
- Example 3 In Example 1, a gas diffusion electrode was obtained in the same manner as in Example 1 except that the thickness of the carbon paper was changed to 120 ⁇ m.
- Example 4 A gas diffusion electrode was obtained in the same manner as in Example 3 except that the carbon black contained in the first microporous layer coating solution was changed to carbon black 2 in Example 1.
- Example 5 In Example 1, a gas diffusion electrode was obtained in the same manner as in Example 1 except that the thickness of the carbon paper was changed to 180 ⁇ m.
- Example 6 A gas diffusion electrode was obtained in the same manner as in Example 5 except that the carbon black contained in the first microporous layer coating liquid was changed to carbon black 2 in Example 1.
- Example 7 In Example 1, a gas diffusion electrode was obtained in the same manner as in Example 1 except that carbon paper having a porosity of 85% and a thickness of 250 ⁇ m was used as the conductive porous substrate. This gas diffusion electrode was incorporated into a single cell for fuel cells in the same manner as in Example 1, and power generation performance was evaluated.
- Example 8 A gas diffusion electrode was obtained in the same manner as in Example 7 except that the carbon black contained in the first microporous layer coating liquid was changed to carbon black 2 in Example 1.
- Example 1 The same procedure as in Example 1 was performed except that the carbon black of the first microporous layer coating solution was changed to carbon black 3 and the carbon black of the surface microporous layer coating solution was changed to carbon black 4 in Example 1. Thus, a gas diffusion electrode was obtained. This gas diffusion electrode was incorporated into a single cell for fuel cells in the same manner as in Example 1, and power generation performance was evaluated. In this example, the pore diameter of the microporous layer close to the surface was 0.15 ⁇ m or less, and formation of a dense layer could not be confirmed.
- Example 2 A gas diffusion electrode was obtained in the same manner as in Example 1, except that the carbon black of the first microporous layer was changed to carbon black 4 in Example 1.
- the pore diameter of the entire microporous layer was 0.15 ⁇ m or less, and formation of a dense layer could not be confirmed.
- Example 9 Example 1 is the same as Example 1 except that the basis weight of the first microporous layer is 13 g / m 2 , the thickness is 18 ⁇ m, the dense layer is 4 ⁇ m, and the thickness of the second microporous layer is 6 ⁇ m. Thus, a gas diffusion electrode was obtained.
- Example 10 A gas diffusion electrode was obtained in the same manner as in Example 9 except that the carbon black contained in the first microporous layer coating solution was changed to carbon black 2 in Example 1.
- Example 11 Example 1 is the same as Example 1 except that the basis weight of the first microporous layer is 13 g / m 2 , the thickness is 18 ⁇ m, the dense layer is 4 ⁇ m, and the thickness of the second microporous layer is 11 ⁇ m. Thus, a gas diffusion electrode was obtained.
- Example 12 A gas diffusion electrode was obtained in the same manner as in Example 11 except that the carbon black contained in the first microporous layer coating solution was changed to carbon black 2 in Example 1.
- Example 13 In Example 1, a gas diffusion electrode was obtained in the same manner as in Example 1 except that the basis weight of the first microporous layer was 28 g / m 2 and the thickness was 48 ⁇ m.
- Example 14 A gas diffusion electrode was obtained in the same manner as in Example 13 except that the carbon black contained in the first microporous layer coating liquid was changed to carbon black 2 in Example 1.
- Example 15 In Example 1, the first microporous layer coating solution was diluted with water so as to be easily soaked into the conductive porous substrate, and the basis weight of the microporous layer was set to 20 g / m 2. A gas diffusion electrode was obtained in the same manner as in Example 1 except that they were substantially matched with each other.
- Example 16 A gas diffusion electrode was obtained in the same manner as in Example 15 except that the carbon black contained in the first microporous layer coating solution was changed to carbon black 2 in Example 1.
- Example 17 In Example 1, a gas diffusion electrode was obtained in the same manner as in Example 1 except that the surface microporous layer coating solution was applied twice.
- Example 18 A gas diffusion electrode was obtained in the same manner as in Example 17 except that the carbon black contained in the first microporous layer coating liquid was changed to carbon black 2 in Example 1.
- Example 19 In Example 1, a gas diffusion electrode was obtained in the same manner as in Example 1 except that the surface microporous layer coating solution was applied four times.
- Example 20 A gas diffusion electrode was obtained in the same manner as in Example 19 except that the carbon black contained in the first microporous layer coating liquid was changed to carbon black 2 in Example 1.
- Example 21 In Example 1, a gas diffusion electrode was obtained in the same manner as in Example 1 except that the carbon black of the surface microporous layer coating solution was changed to carbon black 1.
- Example 22 A gas diffusion electrode was obtained in the same manner as in Example 21 except that the carbon black contained in the first microporous layer coating liquid was changed to carbon black 2 in Example 1. Note that although two types of conductive fine particles in the dense layer were mixed, only one peak was observed in the primary particle size.
- Example 23 A gas diffusion electrode was obtained in the same manner as in Example 1 except that the carbon black in the first microporous layer coating solution was changed to carbon black 3 in Example 1.
- Example 24 In Example 1, only the dense layer was formed by applying the surface microporous layer coating solution in half the amount in order to form only the dense layer in the first microporous layer. In the same manner, a gas diffusion electrode was obtained.
- Example 25 A gas diffusion electrode was obtained in the same manner as in Example 24 except that the carbon black contained in the first microporous layer coating liquid was changed to carbon black 2 in Example 1.
- Example 26 In Example 1, the method for producing the conductive porous substrate was changed. First, the polyacrylonitrile long fiber was subjected to a flameproofing treatment at a temperature of 200 ° C. for 10 minutes, a nonwoven fabric was produced by hydroentanglement treatment, and roll pressing was performed. This was introduced into a heating furnace at a temperature of 2000 ° C. to obtain a conductive porous substrate made of a carbon fiber fired body of nonwoven fabric having a thickness of 150 ⁇ m.
- Example 27 A gas diffusion electrode was obtained in the same manner as in Example 26 except that the carbon black contained in the first microporous layer coating liquid was changed to carbon black 2 in Example 1.
- Example 28 In the first microporous layer coating liquid of Example 1, 15 parts by mass of carbon black 1, 13 parts by mass of FEP dispersion (“Neofluon” (registered trademark) ND-110), surfactant (“TRITON” (registered trademark) ) X-100) A gas diffusion electrode was obtained in the same manner as in Example 1 except for changing to 15 parts by mass and 65 parts by mass of purified water.
- Example 29 A gas diffusion electrode was obtained in the same manner as in Example 28 except that the carbon black contained in the first microporous layer coating liquid was changed to carbon black 2 in Example 1.
- Example 30 In the first microporous layer coating solution of Example 1, 15 parts by mass of carbon black 1, 20 parts by mass of FEP dispersion (“Neofluon” (ND) 110), surfactant (“TRITON” (registered trademark) ) X-100) A gas diffusion electrode was obtained in the same manner as in Example 1 except for changing to 15 parts by mass and 65 parts by mass of purified water.
- the blending amount of the water repellent is 100% or more, so that the water repellent fills the pores, resulting in a decrease in gas diffusibility, and a water repellent as an insulating material between the conductive particles. It is thought that the power generation performance decreased due to the increase in electrical resistance.
- Example 31 A gas diffusion electrode was obtained in the same manner as in Example 28 except that the carbon black contained in the first microporous layer coating liquid was changed to carbon black 2 in Example 1.
- the blending amount of the water repellent is 100% or more, so that the water repellent fills the pores, resulting in a decrease in gas diffusibility, and a water repellent as an insulating material between the conductive particles. It is thought that the power generation performance decreased due to the increase in electrical resistance.
- Example 32 In the first microporous layer coating liquid of Example 1, 15 parts by mass of carbon black 1, 2 parts by mass of FEP dispersion ("Neofluon (registered trademark) ND-110), and surfactant (" TRITON “(registered trademark)) ) X-100) A gas diffusion electrode was obtained in the same manner as in Example 1 except for changing to 15 parts by mass and 65 parts by mass of purified water.
- Example 33 A gas diffusion electrode was obtained in the same manner as in Example 28 except that the carbon black contained in the first microporous layer coating liquid was changed to carbon black 2 in Example 1.
- Example 34 In Example 1, 15 parts by mass of carbon black 1, 5 parts by mass of PTFE dispersion (“Polyflon” (registered trademark) D-210C), and 15 parts by mass of a surfactant (“TRITON” (registered trademark) X-100) Except for changing to 65 parts by mass of purified water, a gas diffusion electrode was obtained in the same manner as in Example 1.
- the melting point of the water repellent contained by collecting 5 mg of the microporous layer with tweezers was measured and found to be 330 ° C. For this reason, it is considered that the drainage performance is lowered because the spread of the resin is small during sintering and the water repellency is lowered. For this reason, compared with Example 1, the power generation performance at a low temperature of 40 degrees was lowered, and the power generation performance at a high temperature of 80 degrees was improved.
- Example 35 A gas diffusion electrode was obtained in the same manner as in Example 30 except that the carbon black contained in the first microporous layer coating liquid was changed to carbon black 2 in Example 1. The same tendency of change in power generation performance as in Example 34 was obtained.
- Example 3 (Comparative Example 3) In Example 1, without forming the first microporous layer, the surface microporous layer coating solution was applied four times to form a dense layer having a thickness of 10 ⁇ m, and then a second microporous layer having a thickness of 15 ⁇ m was formed. Except for this, a gas diffusion electrode was obtained in the same manner as in Example 1.
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Engineering & Computer Science (AREA)
- Composite Materials (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Inert Electrodes (AREA)
- Fuel Cell (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
Abstract
Description
A:導電性多孔質基材
厚み150μm、空隙率85%のカーボンペーパーを以下のように調製して得た。
カーボンブラック1:一次粒子径:0.052μm、DBP吸油量140cc/100g、BET比表面積41m2/g、ストラクチャー指数3.4
カーボンブラック2:一次粒子径:0.045μm、DBP吸油量125cc/100g、BET比表面積41m2/g、ストラクチャー指数3.0
カーボンブラック3:一次粒子径:0.032μm、DBP吸油量175cc/100g、BET比表面積67m2/g、ストラクチャー指数2.6
カーボンブラック4:一次粒子径:0.035μm、DBP吸油量174cc/100g、BET比表面積 254m2/g、ストラクチャー指数0.69
C:撥水剤
“ネオフロン”(登録商標)FEPディスパージョンND-110(FEP樹脂、ダイキン工業(株)製)。
“TRITON”(登録商標)X-100(ナカライテスク(株)製)。
基材(ガス拡散電極および導電性多孔質基材)の厚みについては、(株)ニコン製デジタル厚み計“デジマイクロ”を用いて測定した。基材に0.15MPaの荷重を加えながら測定を行った。
測定すべきガス拡散電極の微多孔層から第1の微多孔層、緻密層、第2の微多孔層を取り出し、500℃の大気中で一時間熱処理した後、それぞれの層に含まれる導電性微粒子を電子顕微鏡を用いて200000倍に拡大して、無作為に選んだ一次粒子の直径を100個測定し、平均した値を各層の一次粒子の平均とした。なお、粒子形分布にピークが複数存在するときは、数種類の導電性微粒子が混合されているとみなし、それぞれのピーク値をそれぞれの一次粒子径とした。
測定すべきガス拡散電極の微多孔層の表面について、(株)キーエンス製レーザー顕微鏡VK-X100を用い、対物レンズ10倍、カットオフなしで5mm角の範囲の粗さ測定を行うことで算術平均粗さRaを求めた。これを、測定場所を変えて10回繰り返し行って、その平均値を表面粗さの値とした。
西華産業(株)製水蒸気ガス水蒸気透過拡散評価装置(MVDP-200C)を用い、ガス拡散電極の一方の面側(1次側)に拡散性を測定したいガスを流し、他方の面側(2次側)に窒素ガスを流す。1次側と2次側の差圧を0Pa近傍(0±3Pa)に制御しておき(即ち圧力差によるガスの流れはほとんどなく、分子拡散によってのみガスの移動現象が起こる)、2次側のガス濃度計により、平衡に達したときのガス濃度を測定し、この値(%)を厚み方向のガス拡散性の指標とした。
西華産業(株)製水蒸気ガス水蒸気透過拡散評価装置(MVDP-200C)を用いた。図5に示すような配管系において、最初にバルブA(303)のみ開いて、バルブB(305)を閉じた状態にしておいて、窒素ガス313を一次側配管A(302)に流した。マスフローコントローラー(301)に所定量(190cc/分)のガスが流れ、圧力コントローラー(304)にガス圧力が大気圧に対して5kPaかかるように調整した。ガス室A(307)とガス室B(309)の間にあるシール材(312)の上にガス拡散電極試料(308)をセットした。次いで、バルブA(303)を閉じ、バルブB(305)を開いて、配管B(306)に窒素ガスが流れるようにした。ガス室A(307)に流入する窒素ガスは、ガス拡散電極試料(308)の空隙を通ってガス室B(309)に移動し、配管C(310)を通過、さらにガス流量計(311)を通過して大気中に放出された。このときのガス流量計(311)を流れるガス流量(cc/分)を測定し、この値を面内方向のガス拡散性とした。
微多孔層の撥水剤の融点の測定方法は示差走査熱量測定により行った。微多孔層のみをガス拡散電極からピンセットにより、採取した。装置はセイコーインスツル株式会社(SII社)製DSC6220を用いて、窒素中において昇温速度2℃/分で、30℃から400℃の温度まで変化させた。その際の吸発熱ピークを観察し、150℃以上の温度での吸熱ピークを融点とした。
得られたガス拡散電極を、電解質膜・触媒層一体化品(日本ゴア(株)製の電解質膜“ゴアセレクト”(登録商標)に、日本ゴア製触媒層“PRIMEA”(登録商標)を両面に形成したもの)の両側に、触媒層と微多孔層が接するように挟み、110℃20分間で2MPaの圧力でホットプレスすることにより、膜電極接合体(MEA)を作製した。この膜電極接合体を燃料電池用単セルに組み込み、電池温度40℃、燃料利用効率を70%、空気利用効率を40%、アノード側の水素、カソード側の空気をそれぞれ露点が75℃、60℃となるように加湿して発電させた。電流密度を高くしていって発電が停止する電流密度の値(限界電流密度)を耐フラッディング性の指標とした。また、電池温度90℃で同様に測定を行い、耐ドライアップ性の指標とした。さらに、通常の運転条件(電池温度70℃)での発電性能も測定した。
ロール状に巻き取られた厚み150μm、空隙率85%のカーボンペーパーを巻き取り式の搬送装置を用いて、搬送しながら、フッ素樹脂濃度を2質量%になるように水に分散した撥水剤ディスパージョンを満たした浸漬槽に浸漬して撥水処理を行った。100℃に設定した乾燥機で乾燥して巻き取り機で巻き取って、撥水処理した導電性多孔質基材を得た。撥水剤ディスパージョンとして、FEPディスパージョン ND-110を水でFEPが2質量%濃度になるように薄めたものを用いた。
カーボンブラック1を15質量部、FEPディスパージョン(“ネオフロン”(登録商標)ND-110)5質量部、界面活性剤(“TRITON”(登録商標)X-100)15質量部、精製水65質量部をプラネタリーミキサーで混練し、塗液を調製した。
カーボンブラック3を5質量部、FEPディスパージョン(“ネオフロン”(登録商標)ND-110)2質量部、界面活性剤(“TRITON”(登録商標)X-100)7質量部、精製水86質量部をプラネタリーミキサーで混練し、塗液を調製した。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例1と同様にしてガス拡散電極を得た。
実施例1において、カーボンペーパーの厚みを120μmに変更した以外は全て、実施例1と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例3と同様にしてガス拡散電極を得た。
実施例1において、カーボンペーパーの厚みを180μmに変更した以外は全て、実施例1と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例5と同様にしてガス拡散電極を得た。
実施例1において、導電性多孔質基材として空隙率85%、厚み250μmのカーボンペーパーを用いた以外は全て、実施例1と同様にしてガス拡散電極を得た。このガス拡散電極を実施例1と同様に燃料電池用単セルに組み込み、発電性能評価を行なった。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例7と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層塗液のカーボンブラックをカーボンブラック3に変更し、表面微多孔層塗液のカーボンブラックをカーボンブラック4に変更した以外は全て、実施例1と同様にしてガス拡散電極を得た。このガス拡散電極を実施例1と同様に燃料電池用単セルに組み込み、発電性能評価を行なった。この例においては、表面に近い微多孔層の細孔径が0.15μm以下となり、緻密層の形成を確認できなかった。
実施例1において、第1の微多孔層のカーボンブラックをカーボンブラック4に変更した以外は全て、実施例1と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層の目付けを13g/m2、厚みを18μm、緻密層を4μm、第2の微多孔層の厚みを6μmに変更した以外は全て、実施例1と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例9と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層の目付けを13g/m2、厚みを18μm、緻密層を4μm、第2の微多孔層の厚みを11μmにしたこと以外は全て、実施例1と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例11と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層の目付けを28g/m2、厚みを48μmにしたこと以外は全て、実施例1と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例13と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層塗液を水で希釈し、導電性多孔質基材にしみこみやすいようにしたうえで、微多孔層の目付けを20g/m2として厚みが実施例1とほぼ合うようにした以外は全て、実施例1と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例15と同様にしてガス拡散電極を得た。
実施例1において、表面微多孔層塗液を2回塗布したこと以外は全て、実施例1と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例17と同様にしてガス拡散電極を得た。
実施例1において、表面微多孔層塗液を4回塗布したこと以外は全て、実施例1と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例19と同様にしてガス拡散電極を得た。
実施例1において、表面微多孔層塗液のカーボンブラックをカーボンブラック1にしたこと以外は全て、実施例1と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例21と同様にしてガス拡散電極を得た。なお緻密層の導電性微粒子が2種類混合されているが、一次粒子径において観察されたピークは1つとなった。
実施例1において、第1の微多孔層塗液のカーボンブラックをカーボンブラック3に変更したこと以外は全て、実施例1と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層に緻密層のみを形成するため表面微多孔層塗液を実施例の半量にして塗布することで緻密層のみを形成したこと以外は全て、実施例1と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例24と同様にしてガス拡散電極を得た。
実施例1において、導電性多孔質基材の作成方法の変更を行った。まずポリアクリロニトリルの長繊維を200℃の温度で10分間の耐炎化処理を行い、水流交絡処理により不織布を作製し、ロールプレスを行った。2000℃の温度の加熱炉に導入し、厚み150μmの不織布の炭素繊維焼成体からなる導電性多孔質基材を得た。さらに、カーボンブラック3とFEP樹脂 “ネオフロン”(登録商標)FEPディスパージョンND-110(ダイキン工業(株)製)を固形分の質量比1:1となるように分散剤と水に分散させた含浸液を作製した。この含浸液に導電性多孔質基材を含浸した後、加熱炉内で380℃の温度で10分間の加熱を行った。その結果、固形分量で5質量%の結着材兼撥水剤で結合ざれた撥水加工済み炭素シートを得た。微多孔層を形成する工程以降は実施例1と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例26と同様にしてガス拡散電極を得た。
実施例1の第1の微多孔層塗液においてカーボンブラック1を15質量部、FEPディスパージョン(“ネオフロン”(登録商標)ND-110)13質量部、界面活性剤(“TRITON”(登録商標)X-100)15質量部、精製水65質量部に変更した以外は全て、実施例1と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例28と同様にしてガス拡散電極を得た。
実施例1の第1の微多孔層塗液においてカーボンブラック1を15質量部、FEPディスパージョン(“ネオフロン”(登録商標)ND-110)20質量部、界面活性剤(“TRITON”(登録商標)X-100)15質量部、精製水65質量部に変更した以外は全て、実施例1と同様にしてガス拡散電極を得た。その結果、撥水剤の配合量が100%以上であるため撥水剤が細孔を埋めてしまいうことでガスの拡散性が低下すること、導電性粒子間に絶縁材料の撥水剤が入ることで電気抵抗の増加が発生し発電性能が低下したと考えられる。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例28と同様にしてガス拡散電極を得た。その結果、撥水剤の配合量が100%以上であるため撥水剤が細孔を埋めてしまいうことでガスの拡散性が低下すること、導電性粒子間に絶縁材料の撥水剤が入ることで電気抵抗の増加が発生し発電性能が低下したと考えられる。
実施例1の第1の微多孔層塗液においてカーボンブラック1を15質量部、FEPディスパージョン(“ネオフロン”(登録商標)ND-110)2質量部、界面活性剤(“TRITON”(登録商標)X-100)15質量部、精製水65質量部に変更した以外は全て、実施例1と同様にしてガス拡散電極を得た。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例28と同様にしてガス拡散電極を得た。
実施例1において、カーボンブラック1を15質量部、PTFEディスパージョン(“ポリフロン”(登録商標)D-210C)5質量部、界面活性剤(“TRITON”(登録商標)X-100)15質量部、精製水65質量部に変更した以外は全て、実施例1と同様にしてガス拡散電極を得た。微多孔層をピンセットで5mg採取して含まれる撥水剤の融点を測定したところ330℃となった。このため焼結時に樹脂の拡がりが小さく撥水性が低くなるため排水性が低下するものと考えられる。このため実施例1に比べて低温の40度での発電性能が低下し、高温の80度での発電性能が向上した。
実施例1において、第1の微多孔層塗液に含まれるカーボンブラックをカーボンブラック2に変更した以外は全て、実施例30と同様にしてガス拡散電極を得た。実施例34と同様の発電性能の変化の傾向を得た。
実施例1において、第1の微多孔層を形成せずに、表面微多孔層塗液を4回塗布して厚み10μmの緻密層を形成した後、厚み15μmの第2の微多孔層を形成したこと以外は全て、実施例1と同様にしてガス拡散電極を得た。
2 巻き出し機
3 ガイドロール(非駆動)
4 第1のダイコーター
5 第2のダイコーター
6 バックロール
7 乾燥機
8 焼結機
9 巻き取り機(駆動)
10 合い紙
11 巻き出し機(合い紙用)
12 塗液タンク
13 送液ポンプ
14 フィルター
21 緻密層の厚み
22 第1の微多孔層の厚み
23 第2の微多孔層の厚み
24 導電性多孔質基材の厚み
31 極大点
32 変曲点
33 ショルダー
40 ロールナイフコーター
41 ナイフロール
42 液ダム
201 第1の微多孔層
202 緻密層
203 第2の微多孔層
204 導電性多孔質基材への微多孔層の浸み込み
205 表面
206 細孔径密度が1.3Aとなる値
207 微多孔層の細孔の平均数密度A
301 マスフローコントローラー
302 配管A
303 バルブA
304 圧力コントローラー
305 バルブB
306 配管B
307 ガス室A
308 ガス拡散電極試料
309 ガス室B
310 配管C
311 ガス流量計
312 シール材
313 窒素ガス
Claims (11)
- 導電性多孔質基材の少なくとも片面に微多孔層を有する、ガス拡散電極であって、微多孔層は導電性多孔質基材に接する第1の微多孔層と、該第1の微多孔層に接する緻密層とを有し、緻密層の厚みが1μm以上であり、
導電性多孔質基材の少なくとも片面に配する微多孔層の、細孔径0.15μm以上1μm以下の細孔の平均数密度をAとしたときに、緻密層の細孔径0.15μm以上1μm以下の細孔の平均数密度Bが1.3A以上である、ガス拡散電極。 - 微多孔層が、緻密層の表面側に接する第2の微多孔層を有する、請求項1記載のガス拡散電極。
- 第2の微多孔層の、細孔径0.15μm以上1μm以下の細孔の平均数密度をCとしたときに、緻密層の細孔径0.15μm以上1μm以下の細孔の平均数密度Bが1.3C以上である、請求項2に記載のガス拡散電極。
- 緻密層の厚みは1μm以上10μm以下であり、第2の微多孔層の厚みは1μm以上10μm以下である、請求項2または3に記載のガス拡散電極。
- 第1の微多孔層は、一次粒子径0.040μm以上0.060μm以下の導電性微粒子を含み、
第2の微多孔層は、一次粒子径が0.015μm以上0.040μm以下の導電性微粒子を含む、請求項2~4のいずれか1項に記載のガス拡散電極。 - 緻密層は、一次粒子径が0.040μm以上0.060μm以下の導電性微粒子、及び一次粒子径が0.015μm以上0.040μm以下の導電性微粒子を含む、請求項1~5のいずれか1項に記載のガス拡散電極。
- 微多孔層が撥水剤を含み、前記撥水剤の融点が、200℃以上320℃以下である、請求項1~6のいずれか1項に記載のガス拡散電極。
- 厚み方向のガス拡散性が30%以上である、請求項1~7のいずれか1項に記載のガス拡散電極。
- 面内方向のガス拡散性が25cc/分以上である、請求項1~8のいずれか1項に記載のガス拡散電極。
- 微多孔層の表面粗さが6μm以下である、請求項1~9のいずれか1項に記載のガス拡散電極。
- 請求項1~10のいずれか1項に記載のガス拡散電極を含む燃料電池。
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2017504125A JP7000855B2 (ja) | 2015-12-24 | 2016-12-16 | ガス拡散電極および燃料電池 |
EP16878582.2A EP3396754B1 (en) | 2015-12-24 | 2016-12-16 | Gas diffusion electrode and fuel cell |
CN201680073681.1A CN108370039B (zh) | 2015-12-24 | 2016-12-16 | 气体扩散电极和燃料电池 |
KR1020187018085A KR20180091853A (ko) | 2015-12-24 | 2016-12-16 | 가스 확산 전극 및 연료 전지 |
CA3001445A CA3001445A1 (en) | 2015-12-24 | 2016-12-16 | Gas diffusion electrode comprising microporous layer on at least one surface thereof and fuel cell comprising such an electrode |
US15/778,529 US10461334B2 (en) | 2015-12-24 | 2016-12-16 | Gas diffusion electrode and fuel cell |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2015-251779 | 2015-12-24 | ||
JP2015251779 | 2015-12-24 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2017110693A1 true WO2017110693A1 (ja) | 2017-06-29 |
Family
ID=59090322
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2016/087627 WO2017110693A1 (ja) | 2015-12-24 | 2016-12-16 | ガス拡散電極および燃料電池 |
Country Status (8)
Country | Link |
---|---|
US (1) | US10461334B2 (ja) |
EP (1) | EP3396754B1 (ja) |
JP (1) | JP7000855B2 (ja) |
KR (1) | KR20180091853A (ja) |
CN (1) | CN108370039B (ja) |
CA (1) | CA3001445A1 (ja) |
TW (1) | TWI706591B (ja) |
WO (1) | WO2017110693A1 (ja) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20210202954A1 (en) * | 2016-01-27 | 2021-07-01 | Toray Industries, Inc. | Gas diffusion electrode, microporous layer paint and production method thereof |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA3015334C (en) * | 2016-03-29 | 2023-11-07 | Toray Industries, Inc. | Gas diffusion electrode base, laminate and fuel cell |
JP7070312B2 (ja) * | 2018-10-11 | 2022-05-18 | トヨタ自動車株式会社 | ガス拡散層用シートの製造方法 |
DE102018219065A1 (de) * | 2018-11-08 | 2020-05-14 | Robert Bosch Gmbh | Elektrodenmaterial und Elektrode zur Betriebsmittelverteilung in einer Brennstoffzelle |
CN112970138B (zh) * | 2018-11-12 | 2024-01-30 | 东丽株式会社 | 气体扩散电极、气体扩散电极的制造方法、膜电极接合体、燃料电池 |
US11684702B2 (en) * | 2019-05-24 | 2023-06-27 | Conmed Corporation | Gap control in electrosurgical instruments using expanded polytetrafluoroethylene |
CN112117465B (zh) * | 2020-08-06 | 2022-06-21 | 江苏大学 | 一种燃料电池气体扩散层及加工方法 |
CN114464820B (zh) * | 2022-04-08 | 2022-07-12 | 湖南隆深氢能科技有限公司 | 一种用于燃料电池gdl疏水工艺的设备 |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006281155A (ja) * | 2005-04-04 | 2006-10-19 | Denso Corp | 触媒体 |
JP2009076451A (ja) * | 2007-08-24 | 2009-04-09 | Toshiba Corp | 燃料電池用電極膜接合体およびそれを用いた燃料電池 |
JP2009199988A (ja) * | 2008-02-25 | 2009-09-03 | Toshiba Corp | 直接メタノール型燃料電池用アノード電極及びそれを用いた直接メタノール型燃料電池 |
JP2010129310A (ja) * | 2008-11-26 | 2010-06-10 | Nissan Motor Co Ltd | 燃料電池用ガス拡散層及びその製造方法 |
JP2011246506A (ja) * | 2010-05-21 | 2011-12-08 | Canon Inc | 高分子多孔質膜及びその製造方法 |
JP2012104408A (ja) * | 2010-11-11 | 2012-05-31 | Honda Motor Co Ltd | 電解質・電極接合体及びその製造方法 |
US20140272664A1 (en) * | 2013-03-15 | 2014-09-18 | Ford Global Technologies, Llc | Microporous layer for a fuel cell |
JP2015526840A (ja) * | 2012-06-13 | 2015-09-10 | ヌヴェラ・フュエル・セルズ・インコーポレーテッド | 電気化学セルと共に使用するためのフロー構造 |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4892606A (en) * | 1986-08-28 | 1990-01-09 | Canon Kabushiki Kaisha | Optical recording medium having space therein and method of manufacturing the same |
JP3773325B2 (ja) | 1997-03-17 | 2006-05-10 | ジャパンゴアテックス株式会社 | 高分子固体電解質燃料電池用ガス拡散層材料及びその接合体 |
JP3444530B2 (ja) | 1998-10-13 | 2003-09-08 | 松下電器産業株式会社 | 燃料電池 |
JP4780814B2 (ja) | 1998-12-15 | 2011-09-28 | 三洋電機株式会社 | 燃料電池 |
JP3382213B2 (ja) | 2000-08-08 | 2003-03-04 | 松下電器産業株式会社 | 高分子電解質型燃料電池用ガス拡散電極の製造方法 |
JP2002352807A (ja) | 2001-05-30 | 2002-12-06 | Toray Ind Inc | ガス拡散体及びその製造方法 |
US20080206615A1 (en) * | 2007-02-22 | 2008-08-28 | Paul Nicotera | Gas diffusion layer with controlled diffusivity over active area |
CN102456891B (zh) * | 2010-10-29 | 2014-07-23 | 中国科学院大连化学物理研究所 | 一种具有梯度孔结构的气体扩散层及其制备和应用 |
JP2014011163A (ja) * | 2012-06-29 | 2014-01-20 | Jntc Co Ltd | ガス拡散層用炭素基材、それを利用したガス拡散層、それを含む燃料電池用電極 |
-
2016
- 2016-12-16 CA CA3001445A patent/CA3001445A1/en active Pending
- 2016-12-16 WO PCT/JP2016/087627 patent/WO2017110693A1/ja unknown
- 2016-12-16 CN CN201680073681.1A patent/CN108370039B/zh active Active
- 2016-12-16 EP EP16878582.2A patent/EP3396754B1/en active Active
- 2016-12-16 US US15/778,529 patent/US10461334B2/en active Active
- 2016-12-16 JP JP2017504125A patent/JP7000855B2/ja active Active
- 2016-12-16 KR KR1020187018085A patent/KR20180091853A/ko active IP Right Grant
- 2016-12-22 TW TW105142596A patent/TWI706591B/zh active
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006281155A (ja) * | 2005-04-04 | 2006-10-19 | Denso Corp | 触媒体 |
JP2009076451A (ja) * | 2007-08-24 | 2009-04-09 | Toshiba Corp | 燃料電池用電極膜接合体およびそれを用いた燃料電池 |
JP2009199988A (ja) * | 2008-02-25 | 2009-09-03 | Toshiba Corp | 直接メタノール型燃料電池用アノード電極及びそれを用いた直接メタノール型燃料電池 |
JP2010129310A (ja) * | 2008-11-26 | 2010-06-10 | Nissan Motor Co Ltd | 燃料電池用ガス拡散層及びその製造方法 |
JP2011246506A (ja) * | 2010-05-21 | 2011-12-08 | Canon Inc | 高分子多孔質膜及びその製造方法 |
JP2012104408A (ja) * | 2010-11-11 | 2012-05-31 | Honda Motor Co Ltd | 電解質・電極接合体及びその製造方法 |
JP2015526840A (ja) * | 2012-06-13 | 2015-09-10 | ヌヴェラ・フュエル・セルズ・インコーポレーテッド | 電気化学セルと共に使用するためのフロー構造 |
US20140272664A1 (en) * | 2013-03-15 | 2014-09-18 | Ford Global Technologies, Llc | Microporous layer for a fuel cell |
Non-Patent Citations (1)
Title |
---|
See also references of EP3396754A4 * |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20210202954A1 (en) * | 2016-01-27 | 2021-07-01 | Toray Industries, Inc. | Gas diffusion electrode, microporous layer paint and production method thereof |
Also Published As
Publication number | Publication date |
---|---|
KR20180091853A (ko) | 2018-08-16 |
EP3396754A4 (en) | 2019-07-03 |
CA3001445A1 (en) | 2017-06-29 |
US10461334B2 (en) | 2019-10-29 |
EP3396754B1 (en) | 2023-02-01 |
TW201801383A (zh) | 2018-01-01 |
JPWO2017110693A1 (ja) | 2018-10-11 |
JP7000855B2 (ja) | 2022-02-04 |
US20180375106A1 (en) | 2018-12-27 |
EP3396754A1 (en) | 2018-10-31 |
CN108370039A (zh) | 2018-08-03 |
TWI706591B (zh) | 2020-10-01 |
CN108370039B (zh) | 2021-01-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP6394748B2 (ja) | ガス拡散電極 | |
WO2017110693A1 (ja) | ガス拡散電極および燃料電池 | |
KR102597863B1 (ko) | 가스 확산 전극 | |
JP6357923B2 (ja) | ガス拡散電極、その製造方法および製造装置 | |
WO2020100649A1 (ja) | ガス拡散電極、ガス拡散電極の製造方法、膜電極接合体、燃料電池 | |
JP6969547B2 (ja) | ガス拡散電極、および、燃料電池 | |
TWI693737B (zh) | 氣體擴散電極及其製造方法 | |
JP6862831B2 (ja) | ガス拡散電極および燃料電池 | |
JP7114858B2 (ja) | ガス拡散電極、および、燃料電池 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
ENP | Entry into the national phase |
Ref document number: 2017504125 Country of ref document: JP Kind code of ref document: A |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 16878582 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 3001445 Country of ref document: CA |
|
ENP | Entry into the national phase |
Ref document number: 20187018085 Country of ref document: KR Kind code of ref document: A |
|
NENP | Non-entry into the national phase |
Ref country code: DE |