JP2007103291A - Manufacturing method of membrane/electrode assembly for direct methanol fuel cell - Google Patents

Manufacturing method of membrane/electrode assembly for direct methanol fuel cell Download PDF

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JP2007103291A
JP2007103291A JP2005294889A JP2005294889A JP2007103291A JP 2007103291 A JP2007103291 A JP 2007103291A JP 2005294889 A JP2005294889 A JP 2005294889A JP 2005294889 A JP2005294889 A JP 2005294889A JP 2007103291 A JP2007103291 A JP 2007103291A
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catalyst layer
cation exchange
membrane
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exchange membrane
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Takashi Egawa
崇 江川
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GS Yuasa Corp
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    • 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
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    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a membrane/electrode assembly for a direct methanol fuel cell in which contact resistance between a catalyst layer and a cation exchange membrane, and the resistance between the catalyst layer and a conductive porous body can be reduced, and diffusing performance of fuel and air in the anode and the cathode can be improved. <P>SOLUTION: This process is subjected to a first process for manufacturing a first laminate (3) of the catalyst layer and a sheet, a second process for manufacturing a second laminate (6) of the catalyst layer and the conductive porous body, a third process for manufacturing a three-layer structure membrane/electrode assembly by joining the first laminate (3) and the cation exchange membrane, and a fourth process for manufacturing a five-layer membrane/electrode assembly by joining the three-layer structure membrane/electrode assembly and the second laminate (6). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、直接メタノール形燃料電池用膜／電極接合体の製造方法に関するものである。   The present invention relates to a method for producing a membrane / electrode assembly for a direct methanol fuel cell.

近年、環境問題や資源問題への対策が重要になっており、その対策の一つとして直接形燃料電池の開発が活発におこなわれている。特に直接メタノール形燃料電池（以降、「ＤＭＦＣ」と略す）は、固体高分子形燃料電池（以降、「ＰＥＦＣ」と略す）と比較して、燃料を改質、ガス化することなく直接発電に利用することができるために、システム構造がシンプルになるので、小形、かつ軽量化が容易である。   In recent years, countermeasures to environmental problems and resource problems have become important, and direct fuel cells are being actively developed as one of the countermeasures. In particular, direct methanol fuel cells (hereinafter abbreviated as “DMFC”) can be directly generated without reforming and gasifying fuel compared to solid polymer fuel cells (hereinafter abbreviated as “PEFC”). Since it can be used, the system structure becomes simple, and it is easy to reduce the size and weight.

ＤＭＦＣでは、アノードに燃料としてメタノール水溶液を、カソードに酸化剤として酸素を供給することによって、電力が得られる。そのアノードおよびカソードでは、次のような電気化学反応がそれぞれ進行する。   In DMFC, power is obtained by supplying a methanol aqueous solution as a fuel to an anode and oxygen as an oxidant to a cathode. The following electrochemical reactions proceed at the anode and cathode, respectively.

アノード：ＣＨ３ＯＨ＋Ｈ２Ｏ→ＣＯ２＋６Ｈ＋＋６ｅ−
カソード：３／２Ｏ２＋６Ｈ＋＋６ｅ−→３Ｈ２Ｏ
全反応：ＣＨ３ＯＨ＋３／２Ｏ２→ＣＯ２＋２Ｈ２Ｏ Anode: CH 3 OH + H 2 O → CO 2 + 6H + + 6e −
Cathode: 3/2 O 2 + 6H + + 6e − → 3H 2 O
Total reaction: CH 3 OH + 3 / 2O 2 → CO 2 + 2H 2 O

このようなＤＭＦＣでは、Ｎａｆｉｏｎ（ＤｕＰｏｎｔ社の登録商標）に代表されるパーフルオロスルホン酸を主体とする陽イオン交換膜が用いられてきた。また、アノードにはアセチレンブラック等の高比表面積の炭素粉末上にナノサイズの白金とルテニウムとを担持させた電極触媒を用いて、撥水性を付与するためにＰＴＦＥ（ポリテトラフルオロエチレン）を混合し、プロトン伝導性を付与し、かつ結着剤として作用するパーフルオロスルホン酸系の陽イオン交換樹脂を混合している。カソードも基本的にアノードと同じ構成であるが、カソードではＣＯ被毒が生じにくいために、電極触媒として、高比表面積の炭素粉末上に白金を担持したものを用いている。   In such a DMFC, a cation exchange membrane mainly composed of perfluorosulfonic acid represented by Nafion (registered trademark of DuPont) has been used. In addition, PTFE (polytetrafluoroethylene) is mixed in the anode to provide water repellency using an electrode catalyst in which nano-sized platinum and ruthenium are supported on carbon powder with a high specific surface area such as acetylene black. In addition, a perfluorosulfonic acid cation exchange resin which imparts proton conductivity and acts as a binder is mixed. The cathode has basically the same structure as the anode, but since CO poisoning is unlikely to occur at the cathode, an electrode catalyst having platinum supported on carbon powder having a high specific surface area is used.

アノードやカソードの外側には、ＰＴＦＥにより撥水性を付与したカーボンペーパーやカーボンクロスを導電性多孔質体として配置している。このような陽イオン交換膜と触媒層とで構成されるＤＭＦＣ用の電極を膜／電極接合体（以降、「ＭＥＡ」と略す）と称している。   On the outside of the anode and the cathode, carbon paper or carbon cloth imparted with water repellency by PTFE is disposed as a conductive porous body. An electrode for DMFC composed of such a cation exchange membrane and a catalyst layer is referred to as a membrane / electrode assembly (hereinafter abbreviated as “MEA”).

このＭＥＡの製作方法としては、触媒層を導電性多孔質体上に形成して陽イオン交換膜と接合する方法と触媒層をシート上に形成して陽イオン交換膜に転写する方法の２つの方法が知られている。   There are two methods for manufacturing this MEA: a method in which a catalyst layer is formed on a conductive porous body and bonded to a cation exchange membrane, and a method in which a catalyst layer is formed on a sheet and transferred to a cation exchange membrane. The method is known.

特許文献１には、アルコールなどの溶媒中に貴金属触媒粒子・カーボン粒子・高分子電解質・ポリテトラフルオロエチレン粒子を分散させた触媒分散溶液を、多孔質基体の表面に塗布あるいは噴霧し、乾燥して溶媒を除去し、多孔質基体の表面に触媒をとりつける製造方法が開示され、また、特許文献２には、アノードやカソードの触媒層を導電性多孔質体上に形成して、Ｎａｆｉｏｎなどの陽イオン交換膜と接合する方法が開示されている。   In Patent Document 1, a catalyst dispersion solution in which noble metal catalyst particles, carbon particles, polymer electrolyte, and polytetrafluoroethylene particles are dispersed in a solvent such as alcohol is applied to or sprayed on the surface of a porous substrate and dried. A manufacturing method in which the solvent is removed and the catalyst is attached to the surface of the porous substrate is disclosed, and Patent Document 2 discloses that a catalyst layer of an anode or a cathode is formed on a conductive porous body, and Nafion or the like is formed. A method of joining with a cation exchange membrane is disclosed.

特許文献３には、フィルム上に形成した触媒層を、電解質として用いるイオン交換膜に転写し、一体化して触媒層−電解質接合体を形成するＭＥＡの製造方法が開示され、また、特許文献４には、表面に触媒層を形成した触媒層形成基体（シート）を、触媒層面が固体高分子電解質膜に接するように、固体高分子電解質膜の片面または両面に積層し、加熱圧接して触媒層を固体高分子電解質膜に転写した後、触媒層形成基体を除去するＭＥＡの製造方法が開示されている。さらに、非特許文献１にも、アノードやカソードの触媒層を別のシート上に形成して、陽イオン交換膜の両面に転写する方法が開示されている。   Patent Document 3 discloses a method for producing MEA in which a catalyst layer formed on a film is transferred to an ion exchange membrane used as an electrolyte and integrated to form a catalyst layer-electrolyte assembly. The catalyst layer-forming substrate (sheet) having a catalyst layer formed on the surface is laminated on one or both sides of the solid polymer electrolyte membrane so that the catalyst layer surface is in contact with the solid polymer electrolyte membrane, and heated and pressed to form a catalyst. An MEA manufacturing method is disclosed in which a catalyst layer-forming substrate is removed after the layer is transferred to a solid polymer electrolyte membrane. Further, Non-Patent Document 1 discloses a method in which an anode or cathode catalyst layer is formed on another sheet and transferred onto both surfaces of the cation exchange membrane.

特許文献１または特許文献２で開示された、触媒層を導電性多孔質体上に形成して陽イオン交換膜と接合するＭＥＡの製造方法には、表面積が大きい導電性多孔質体に触媒層を形成することによって、多孔質体と触媒層との界面における接触面積が大きくなるので、多孔質体と触媒層との間の接触抵抗が小さくなるという利点がある。   In the MEA manufacturing method disclosed in Patent Document 1 or Patent Document 2 in which a catalyst layer is formed on a conductive porous body and joined to a cation exchange membrane, the catalyst porous layer has a large surface area. Since the contact area at the interface between the porous body and the catalyst layer is increased, the contact resistance between the porous body and the catalyst layer is reduced.

一方、特許文献３、特許文献４または非特許文献１で開示された、触媒層をシート上に形成して陽イオン交換膜に転写するＭＥＡの製造方法には、触媒層を別のシート上に形成したのちに、陽イオン交換膜に転写するために、転写時の圧力を高くすることによって、陽イオン交換膜と触媒層を十分に接着させることができるという利点がある。   On the other hand, in the MEA manufacturing method disclosed in Patent Document 3, Patent Document 4 or Non-Patent Document 1 for forming a catalyst layer on a sheet and transferring it to a cation exchange membrane, the catalyst layer is placed on another sheet. In order to transfer to the cation exchange membrane after the formation, there is an advantage that the cation exchange membrane and the catalyst layer can be sufficiently adhered by increasing the pressure at the time of transfer.

特開平１０−２２３２３３号公報Japanese Patent Laid-Open No. 10-223233 特開２００４−３０３６１０号公報JP 2004-303610 A 特開平１０−０６４５７４号公報Japanese Patent Laid-Open No. 10-064574 特開２０００−０９０９４４号公報JP 2000-090944 A Ｍ．Ｓ．Ｗｉｌｓｏｎ，Ｊ．Ａｐｐｌ．Ｅｌｅｃｔｒｏｃｈｅｍ．，２２，１（１９９２）M.M. S. Wilson, J .; Appl. Electrochem. , 22, 1 (1992)

しかしながら、触媒層を導電性多孔質体上に形成して陽イオン交換膜と接合するＭＥＡの製造方法では、陽イオン交換膜と接合する際、触媒層と膜とを十分接着させるためには接合圧力を高くする必要があり、その結果導電性多孔質体が潰れすぎるので、燃料やガスの拡散性が低下することによって、分極特性が低下する。また、導電性多孔質体が潰れ過ぎないように接合圧力を低くすると、触媒層と膜との接着が不十分になり、接触抵抗が増大することによって、分極特性が低下するという問題があった。   However, in the MEA manufacturing method in which the catalyst layer is formed on the conductive porous body and bonded to the cation exchange membrane, when the catalyst layer and the membrane are sufficiently bonded when bonded to the cation exchange membrane, bonding is required. It is necessary to increase the pressure, and as a result, the conductive porous body is crushed too much, so that the diffusibility of the fuel and gas is lowered, and the polarization characteristics are lowered. Further, if the bonding pressure is lowered so that the conductive porous body is not crushed too much, there is a problem that the adhesion between the catalyst layer and the film becomes insufficient and the contact resistance increases, thereby degrading the polarization characteristics. .

また、触媒層をシート上に形成して陽イオン交換膜に転写するＭＥＡの製造方法には、触媒層に転写したのちに、導電性多孔質体を触媒層の両面に配した際に、触媒層表面が平滑であるために、導電性多孔質体と触媒層との間の接触抵抗が増大することによって、分極特性が低下することがある。   Further, in the MEA manufacturing method in which the catalyst layer is formed on the sheet and transferred to the cation exchange membrane, the catalyst is transferred to the catalyst layer and then the conductive porous body is disposed on both sides of the catalyst layer. Since the surface of the layer is smooth, the polarization characteristics may be deteriorated by increasing the contact resistance between the conductive porous body and the catalyst layer.

以上のことから、これまでの方法で製作されたＭＥＡを備えたＤＭＦＣは、高電流密度領域における分極が大きいという問題があった。   From the above, the DMFC including the MEA manufactured by the conventional method has a problem that the polarization in the high current density region is large.

発明者は、これまでの方法で製作されたＭＥＡを備えたＤＭＦＣが、高電流密度領域における分極が大きい原因を鋭意実験によって検討した結果、その主原因は、導電性多孔質体と触媒層との間、もしくは触媒層と陽イオン交換膜との間の接触抵抗が高いことに起因することを見出した。   The inventor has intensively studied the cause of the large polarization in the high current density region of the DMFC equipped with the MEA manufactured by the conventional method. As a result, the main causes are the conductive porous body, the catalyst layer, and the like. Or the contact resistance between the catalyst layer and the cation exchange membrane was found to be high.

また、ＭＥＡの製造方法によっては、導電性多孔質体が潰れすぎることによって、アノードおよびカソードにおける燃料および空気の拡散性が低下することも上記の原因の一部になっていることを見出した。   Further, it has been found that depending on the MEA manufacturing method, the diffusibility of fuel and air at the anode and the cathode may be partly caused by excessively collapsing the conductive porous body.

ＤＭＦＣが広範囲な電流密度において優れた分極特性を発揮するためには、これらの接触抵抗とアノードおよびカソードにおける燃料および空気の拡散性とを改善することが必要不可欠となる。   In order for DMFCs to exhibit excellent polarization characteristics over a wide range of current densities, it is essential to improve their contact resistance and fuel and air diffusivity at the anode and cathode.

本発明の目的は、触媒層と陽イオン交換膜との間、および触媒層と導電性多孔質体との間の接触抵抗を低減し、かつアノードおよびカソードにおける燃料および空気の拡散性を改善することができる直接メタノール形燃料電池用膜／電極接合体（ＤＭＦＣ用ＭＥＡ）の製造方法を提供することである。   The object of the present invention is to reduce the contact resistance between the catalyst layer and the cation exchange membrane and between the catalyst layer and the conductive porous body, and improve the diffusibility of fuel and air at the anode and cathode A method of manufacturing a membrane / electrode assembly for direct methanol fuel cell (MEA for DMFC) that can be used.

本発明は、炭素材料と触媒金属と陽イオン交換樹脂とを含む触媒層を陽イオン交換膜の両面に配し、さらにその外側の両面に導電性多孔質体を配した直接メタノール形燃料電池用膜／電極接合体の製造方法において、炭素材料と触媒金属と陽イオン交換樹脂とを含むスラリーをシート上に塗布・乾燥して、触媒層とシートとの第１の積層体（３）を製作する第１の工程と、炭素材料と触媒金属と陽イオン交換樹脂溶液とを含むスラリーを導電性多孔質体上に塗布・乾燥して、触媒層と導電性多孔質体との第２の積層体（６）を製作する第２の工程と、前記第１の積層体（３）の触媒層が陽イオン交換膜に接するように、前記第１の積層体（３）を陽イオン交換膜の少なくとも一方の面に接合した後、シートを剥離し、膜／電極接合体を製作する第３の工程と、前記第２の積層体（６）の触媒層が前記膜／電極接合体の触媒層に接するように、前記第２の積層体（６）を前記膜／電極接合体に接合する第４の工程を経ることを特徴とする。   The present invention is for a direct methanol fuel cell in which a catalyst layer containing a carbon material, a catalyst metal, and a cation exchange resin is arranged on both sides of a cation exchange membrane, and a conductive porous body is arranged on both sides of the catalyst layer. In the method for producing a membrane / electrode assembly, a slurry containing a carbon material, a catalyst metal, and a cation exchange resin is applied to a sheet and dried to produce a first laminate (3) of the catalyst layer and the sheet. And applying a slurry containing a carbon material, a catalyst metal, and a cation exchange resin solution to the conductive porous body and drying to form a second laminate of the catalyst layer and the conductive porous body. A second step of manufacturing the body (6), and the first laminate (3) of the cation exchange membrane so that the catalyst layer of the first laminate (3) is in contact with the cation exchange membrane. After bonding to at least one surface, the sheet is peeled off to produce a membrane / electrode assembly. In the third step, the second laminate (6) is used as the membrane / electrode assembly so that the catalyst layer of the second laminate (6) is in contact with the catalyst layer of the membrane / electrode assembly. A fourth step of joining is performed.

本発明の製造方法によって得られた直接メタノール形燃料電池用膜／電極接合体（ＤＦＣ用ＭＥＡ）は、導電性多孔質体と触媒層との間、および触媒層と陽イオン交換膜との間の接触抵抗が低くなる。   The membrane / electrode assembly for direct methanol fuel cell (MEA for DFC) obtained by the production method of the present invention is between the conductive porous body and the catalyst layer, and between the catalyst layer and the cation exchange membrane. The contact resistance is reduced.

また、本発明では、導電性多孔質体上に形成した触媒層を接合する際、陽イオン交換膜に直接接合するのではなく、あらかじめ陽イオン交換膜に形成した触媒層に接合する。触媒層同士を接合する場合、圧力を高くしなくても、十分接着できるために、導電性多孔質体を潰しすぎることなく接合することが可能である。その結果、アノードおよびカソードにおける燃料および空気の拡散性が向上し、高電流密度領域における分極特性に優れたＤＭＦＣを提供することが可能となる。   Moreover, in this invention, when joining the catalyst layer formed on the electroconductive porous body, it joins to the catalyst layer previously formed in the cation exchange membrane instead of joining directly to a cation exchange membrane. When the catalyst layers are bonded to each other, the conductive porous bodies can be bonded without being crushed because they can be sufficiently bonded without increasing the pressure. As a result, the diffusibility of fuel and air at the anode and the cathode is improved, and a DMFC having excellent polarization characteristics in a high current density region can be provided.

以下、本発明の実施形態により本願発明について詳細に説明する。   Hereinafter, the present invention will be described in detail according to embodiments of the present invention.

本発明におけるＤＭＦＣ用ＭＥＡの製造方法は、次の４つの工程を経るものである。すなわち、炭素材料と触媒金属と陽イオン交換樹脂とを含む触媒層を陽イオン交換膜の両面に配し、さらにその外側の両面に導電性多孔質体を配した直接メタノール形燃料電池用膜／電極接合体の製造方法において、炭素材料と触媒金属と陽イオン交換樹脂とを含むスラリーをシート上に塗布・乾燥して、触媒層とシートとの第１の積層体（３）を製作する第１の工程と、炭素材料と触媒金属と陽イオン交換樹脂溶液とを含むスラリーを導電性多孔質体上に塗布・乾燥して、触媒層と導電性多孔質体との第２の積層体（６）を製作する第２の工程と、前記第１の積層体（３）の触媒層が陽イオン交換膜に接するように、前記第１の積層体（３）を陽イオン交換膜の少なくとも一方の面に接合した後、シートを剥離し、膜／電極接合体を製作する第３の工程と、前記第２の積層体（６）の触媒層が膜／電極接合体の触媒層に接するように、前記第２の積層体（６）を前記膜／電極接合体に接合する第４の工程を経ることを特徴とする。   The manufacturing method of the DMFC MEA in the present invention includes the following four steps. That is, a direct methanol fuel cell membrane in which a catalyst layer containing a carbon material, a catalyst metal, and a cation exchange resin is arranged on both sides of a cation exchange membrane, and a conductive porous body is arranged on both sides of the catalyst layer / In the method for producing an electrode assembly, a slurry containing a carbon material, a catalyst metal, and a cation exchange resin is applied to a sheet and dried to produce a first laminate (3) of the catalyst layer and the sheet. A second laminate of a catalyst layer and a conductive porous body (1), a slurry containing a carbon material, a catalyst metal, and a cation exchange resin solution is applied and dried on the conductive porous body; 6) and at least one of the cation exchange membranes so that the catalyst layer of the first laminate (3) is in contact with the cation exchange membrane. After bonding to the surface, peel off the sheet and manufacture the membrane / electrode assembly Third step and bonding the second laminate (6) to the membrane / electrode assembly so that the catalyst layer of the second laminate (6) is in contact with the catalyst layer of the membrane / electrode assembly A fourth step is performed.

本発明の、第１の積層体（３）と第２の積層体（６）とを互いの触媒層が接するように接合したＤＭＦＣ用膜／電極接合体は、アノード側およびカソード側に用いることができるが、触媒層が厚くなり、触媒層に含まれる触媒量を多くすることができることから、アノード側に用いることが好ましい。   The membrane / electrode assembly for DMFC in which the first laminate (3) and the second laminate (6) of the present invention are joined so that the catalyst layers are in contact with each other is used on the anode side and the cathode side. However, since the catalyst layer becomes thick and the amount of catalyst contained in the catalyst layer can be increased, it is preferably used on the anode side.

本発明の製造方法の各工程で得られる第１の積層体、第２の積層体、膜／電極接合体の断面構造を図１〜図８に示す。図１〜図８において、記号１は触媒層、１ａはアノード触媒層、１ｃはカソード触媒層、２はシート、３は第１の積層体、４は触媒層、４ａはアノード触媒層、４ｃはカソード触媒層、５は導電性多孔質体、６は第２の積層体、７は陽イオン交換膜、８ａはアノード触媒層、８ｃはカソード触媒層である。   1 to 8 show the cross-sectional structures of the first laminate, the second laminate, and the membrane / electrode assembly obtained in each step of the production method of the present invention. 1 to 8, symbol 1 is a catalyst layer, 1a is an anode catalyst layer, 1c is a cathode catalyst layer, 2 is a sheet, 3 is a first laminate, 4 is a catalyst layer, 4a is an anode catalyst layer, 4c is The cathode catalyst layer, 5 is a conductive porous body, 6 is a second laminate, 7 is a cation exchange membrane, 8a is an anode catalyst layer, and 8c is a cathode catalyst layer.

本発明の製造方法における第１の工程では、炭素材料と触媒金属と陽イオン交換樹脂とを含むスラリーをシート上に塗布・乾燥して、触媒層とシートとの第１の積層体３を製作する。図１に第１の工程で得られた第１の積層体３の断面構造を示す。第１の積層体３は触媒層１とシート２とが積層されたものである。なお、触媒層１には、用いる触媒によって、アノード触媒層１ａとカソード触媒層１ｃの２種類がある。   In the first step of the production method of the present invention, a slurry containing a carbon material, a catalyst metal, and a cation exchange resin is applied onto a sheet and dried to produce a first laminate 3 of a catalyst layer and a sheet. To do. FIG. 1 shows a cross-sectional structure of the first laminate 3 obtained in the first step. The first laminate 3 is obtained by laminating a catalyst layer 1 and a sheet 2. There are two types of catalyst layers 1, an anode catalyst layer 1 a and a cathode catalyst layer 1 c, depending on the catalyst used.

第１の工程で使用する炭素材料としては、電子伝導性の高いものが好ましく、ファーネスブラック、チャンネルブラック、アセチレンブラック等のカーボンブラック以外に、気相成長炭素、活性炭や黒鉛などが使用できる。さらに、炭素材料の電子伝導性を向上させるために炭素材料にホウ素がドープされたもの、炭素材料の分散性を向上させるために炭素材料の表面に酸素原子を含む官能基、あるいは窒素原子を含む官能基を備えたものも使用することができる。   As the carbon material used in the first step, a material having high electron conductivity is preferable. In addition to carbon black such as furnace black, channel black, and acetylene black, vapor grown carbon, activated carbon, graphite, and the like can be used. Furthermore, the carbon material is doped with boron in order to improve the electronic conductivity of the carbon material, the surface of the carbon material contains a functional group containing an oxygen atom or a nitrogen atom in order to improve the dispersibility of the carbon material. The thing provided with the functional group can also be used.

第１の工程で使用する触媒金属としては、メタノールの酸化反応および酸素の還元反応に触媒作用を有するものが好ましく、白金、ルテニウム、イリジウム、ロジウム、パラジウム、オスミウムなどの白金族金属、またはそれらの合金から選択することができる。さらに、マグネシウム、アルミニウム、バナジウム、クロム、マンガン、鉄、コバルト、ニッケル、銅、亜鉛、銀またはタングステンからなる群から選ばれた少なくとも一つの元素と白金族金属とを含む合金を使用することもできる。   The catalyst metal used in the first step is preferably one having a catalytic action for methanol oxidation reaction and oxygen reduction reaction, platinum group metals such as platinum, ruthenium, iridium, rhodium, palladium, osmium, or their It can be selected from alloys. Furthermore, an alloy containing at least one element selected from the group consisting of magnesium, aluminum, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, silver, or tungsten and a platinum group metal can also be used. .

第１の工程で使用する陽イオン交換樹脂としては、パーフルオロカーボンスルホン酸形、スチレン−ジビニルベンゼン系のスルホン酸形陽イオン交換樹脂、またはイオン交換基として、カルボン酸基、ホスホン酸基およびリン酸基を備えた陽イオン交換樹脂が好ましい。また、ポリオレフィンやポリイミドのような炭化水素を骨格とするものも使用することができる。   Examples of the cation exchange resin used in the first step include perfluorocarbon sulfonic acid type, styrene-divinylbenzene sulfonic acid type cation exchange resin, or ion exchange groups such as carboxylic acid group, phosphonic acid group and phosphoric acid. Cation exchange resins with groups are preferred. Moreover, what has a hydrocarbon skeleton such as polyolefin and polyimide can also be used.

第１の工程で使用するシートの材料としては、高分子フィルムや金属箔を使用することができる。   As a material for the sheet used in the first step, a polymer film or a metal foil can be used.

第１の工程でスラリーをシート上に塗布する方法には、リバースロール法、コンマバー法、グラビヤ法、およびエアーナイフ法などの任意のコーターヘッドを用いることができる。スクリーン印刷法、ドクターブレード法、ディップコート法およびスプレーコート法などによっても塗布することができる。また、この工程における乾燥方法としては、放置乾燥のほかに、送風乾燥機、温風乾燥機、赤外線加熱機、遠赤外線加熱機などが使用できるが、特に限定されるものではない。   As a method of applying the slurry on the sheet in the first step, any coater head such as a reverse roll method, a comma bar method, a gravure method, and an air knife method can be used. It can be applied by a screen printing method, a doctor blade method, a dip coating method or a spray coating method. Moreover, as a drying method in this step, in addition to the standing drying, a blower dryer, a hot air dryer, an infrared heater, a far infrared heater, or the like can be used, but is not particularly limited.

本発明の製造方法における第２の工程では、炭素材料と触媒金属と陽イオン交換樹脂溶液とを含むスラリーを導電性多孔質体上に塗布・乾燥して、触媒層と導電性多孔質体との第２の積層体６を製作する。   In the second step in the production method of the present invention, a slurry containing a carbon material, a catalyst metal, and a cation exchange resin solution is applied and dried on the conductive porous body, and the catalyst layer, the conductive porous body, The second laminated body 6 is manufactured.

図２に第２の工程で得られた第２の積層体６の断面構造を示す。第２の積層体６は触媒層４と導電性多孔質体５とが積層されたものである。なお、触媒層４には、用いる触媒によって、アノード触媒層４ａとカソード触媒層４ｃの２種類がある。   FIG. 2 shows a cross-sectional structure of the second laminate 6 obtained in the second step. The second laminate 6 is obtained by laminating the catalyst layer 4 and the conductive porous body 5. There are two types of catalyst layers 4, an anode catalyst layer 4 a and a cathode catalyst layer 4 c, depending on the catalyst used.

第２の工程で使用する炭素材料、触媒金属および陽イオン交換樹脂としては、第１の工程で使用することのできるのと同じ材料を使用することができる。なお、炭素材料、触媒金属および陽イオン交換樹脂は、第１の工程と第２の工程で、同じ材料を用いてもよいし、異なる材料を用いてもよい。   As the carbon material, catalyst metal, and cation exchange resin used in the second step, the same materials that can be used in the first step can be used. Note that the carbon material, the catalyst metal, and the cation exchange resin may be the same material or different materials in the first step and the second step.

第２の工程で使用する導電性多孔質体としては、カーボンペーパー、カーボンフェルトやカーボンクロスなどを使用することができる。   As the conductive porous material used in the second step, carbon paper, carbon felt, carbon cloth, or the like can be used.

第２の工程でスラリーを導電性多孔質体上に塗布する方法、また乾燥方法としては、第１の工程で使用することのできるのと同じ方法を使用することができる。なお、塗布方法および乾燥方法は、第１の工程と第２の工程で、同じ方法を用いてもよいし、異なる方法を用いてもよい。   As a method for applying the slurry on the conductive porous body in the second step and a drying method, the same method that can be used in the first step can be used. In addition, the application method and the drying method may use the same method in a 1st process and a 2nd process, and may use a different method.

本発明の製造方法における第３の工程では、第１の工程で得られた第１の積層体３の触媒層が陽イオン交換膜に接するように、第１の積層体３を陽イオン交換膜の少なくとも一方の面に接合した後、シートを剥離し、膜／電極接合体を製作する。   In the 3rd process in the manufacturing method of this invention, the 1st laminated body 3 is made into a cation exchange membrane so that the catalyst layer of the 1st laminated body 3 obtained at the 1st process may contact | connect a cation exchange membrane. After joining to at least one side of the sheet, the sheet is peeled off to produce a membrane / electrode assembly.

まず、第３の工程において、陽イオン交換膜の片面に触媒層が接合された二層構造の膜／電極接合体を作製する手順を説明する。   First, in the third step, a procedure for producing a membrane / electrode assembly having a two-layer structure in which a catalyst layer is joined to one surface of a cation exchange membrane will be described.

図３に、第１の工程で得られた第１の積層体の触媒層が陽イオン交換膜に接するように、第１の積層体３を陽イオン交換膜の片面に接合して得られた二層構造の膜／電極接合体の断面構造を示す。図３（Ａ）はシートを剥離する前の状態、図３（Ｂ）はシートを剥離した後の状態を示す。   In FIG. 3, the first laminate 3 was obtained by bonding to one side of the cation exchange membrane so that the catalyst layer of the first laminate obtained in the first step was in contact with the cation exchange membrane. 2 shows a cross-sectional structure of a two-layer membrane / electrode assembly. FIG. 3A shows a state before peeling the sheet, and FIG. 3B shows a state after peeling the sheet.

図３（Ａ）では、陽イオン交換膜７の片面に、第１の積層体（１ａ＋２）のアノード触媒層１ａが陽イオン交換膜に接するように、第１の積層体が接合され、シート２はアノード触媒層１ａに張り付いている。シート２を剥離した後は図３（Ｂ）に示したように、アノード触媒層１ａ／陽イオン交換膜７からなる二層構造の膜／電極接合体となる。   In FIG. 3A, the first laminate is joined to one surface of the cation exchange membrane 7 such that the anode catalyst layer 1a of the first laminate (1a + 2) is in contact with the cation exchange membrane, and the sheet 2 Is attached to the anode catalyst layer 1a. After the sheet 2 is peeled off, as shown in FIG. 3B, a membrane / electrode assembly having a two-layer structure comprising the anode catalyst layer 1a / cation exchange membrane 7 is obtained.

つぎに、第３の工程において、陽イオン交換膜の両面に触媒層が接合された三層構造の膜／電極接合体を作製する手順を説明する。   Next, in the third step, a procedure for producing a membrane / electrode assembly having a three-layer structure in which catalyst layers are bonded to both surfaces of a cation exchange membrane will be described.

図４に、第１の工程で得られた第１の積層体の触媒層が陽イオン交換膜に接するように、第１の積層体を陽イオン交換膜の両面に接合して得られた三層構造の膜／電極接合体の断面構造を示す。図４（Ａ）はシートを剥離する前の状態、図４（Ｂ）はシートを剥離した後の状態を示す。   FIG. 4 shows three samples obtained by bonding the first laminate to both surfaces of the cation exchange membrane so that the catalyst layer of the first laminate obtained in the first step is in contact with the cation exchange membrane. The cross-sectional structure of a layered membrane / electrode assembly is shown. 4A shows a state before the sheet is peeled off, and FIG. 4B shows a state after the sheet is peeled off.

図４（Ａ）では、陽イオン交換膜７の両面に、第１の積層体のアノード触媒層１ａおよびカソード触媒層１ｃが陽イオン交換膜に接するように、第１の積層体が接合され、シート２はアノード触媒層１ａおよびカソード触媒層１ｃに張り付いている。シート２を剥離した後は図４（Ｂ）に示したように、アノード触媒層１ａ／陽イオン交換膜７／カソード触媒層１ｃからなる三層構造の膜／電極接合体となる。   In FIG. 4A, the first laminate is bonded to both surfaces of the cation exchange membrane 7 such that the anode catalyst layer 1a and the cathode catalyst layer 1c of the first laminate are in contact with the cation exchange membrane. The sheet 2 is attached to the anode catalyst layer 1a and the cathode catalyst layer 1c. After the sheet 2 is peeled off, as shown in FIG. 4B, a membrane / electrode assembly having a three-layer structure comprising the anode catalyst layer 1a / cation exchange membrane 7 / cathode catalyst layer 1c is obtained.

第３の工程で使用する陽イオン交換膜としては、第１の工程で使用することのできる陽イオン交換樹脂と同じ材料を使用することができる。   As the cation exchange membrane used in the third step, the same material as the cation exchange resin that can be used in the first step can be used.

この第３の工程での接合は、加熱圧着することによりおこなうことができる。加熱圧着の温度は、陽イオン交換樹脂のガラス転移温度の近傍である１２０℃以上、２００℃以下であることが好ましく、加熱圧着の圧力は１００ｋｇｆ／ｃｍ２以上、４００ｋｇｆ／ｃｍ２以下であることが好ましい。 The joining in the third step can be performed by thermocompression bonding. Temperature of thermocompression bonding, the cation exchange resin having a glass transition temperature near a is 120 ° C. or more, and is preferably 200 ° C. or less, that the pressure of thermocompression bonding is 100 kgf / cm 2 or more and 400 kgf / cm 2 or less Is preferred.

１２０℃より低い温度、あるいは１００ｋｇｆ／ｃｍ２より低い圧力の場合では、触媒層と陽イオン交換膜との接着が不十分になる恐れがあり、２００℃より高い温度、あるいは４００ｋｇｆ／ｃｍ２より高い圧力の場合では、陽イオン交換膜が分解、もしくは破損するおそれがある。さらに、加熱圧着するための装置は特に限定されないが、平プレス機あるいはロールプレス機を用いることができる。 In the case of a temperature lower than 120 ° C. or a pressure lower than 100 kgf / cm 2 , there is a possibility that the adhesion between the catalyst layer and the cation exchange membrane may be insufficient, and a temperature higher than 200 ° C. or higher than 400 kgf / cm 2. In the case of pressure, the cation exchange membrane may be decomposed or damaged. Furthermore, the apparatus for thermocompression bonding is not particularly limited, but a flat press machine or a roll press machine can be used.

本発明の製造方法における第４の工程では、第２の工程で得られた触媒層と導電性多孔質体との第２の積層体を、第３の工程で得られた触媒層／陽イオン交換膜からなる二層構造の膜／電極接合体または触媒層／陽イオン交換膜／触媒層からなる三層構造の膜／電極接合体に接合する。   In the 4th process in the manufacturing method of this invention, the 2nd laminated body of the catalyst layer obtained by the 2nd process and an electroconductive porous body is used for the catalyst layer / cation obtained by the 3rd process. The membrane / electrode assembly having a two-layer structure composed of an exchange membrane or the membrane / electrode assembly having a three-layer structure composed of a catalyst layer / cation exchange membrane / catalyst layer is joined.

まず、第３の工程で得られた二層構造の膜／電極接合体に第２の積層体６を接合する手順を説明する。図５は、二層構造の膜／電極接合体に第２の積層体６を、お互いの触媒層が接するように接合したアノード側膜／電極接合体の断面構造を示し、図５において、二層構造の膜／電極接合体の触媒層１ａと、第２の積層体（４ａ＋５）の触媒層４ａが接するように接合されている。そして、触媒層１ａと触媒層４ａを合わせてアノード触媒層８ａとなる。得られた接合体の構造は、導電性多孔質体５／アノード触媒層８ａ／陽イオン交換膜７となっている。   First, a procedure for joining the second laminate 6 to the two-layer membrane / electrode assembly obtained in the third step will be described. FIG. 5 shows a cross-sectional structure of an anode side membrane / electrode assembly in which the second laminate 6 is joined to a membrane / electrode assembly having a two-layer structure so that the catalyst layers are in contact with each other. The catalyst layer 1a of the layered membrane / electrode assembly and the catalyst layer 4a of the second laminate (4a + 5) are joined so as to contact each other. The catalyst layer 1a and the catalyst layer 4a are combined to form an anode catalyst layer 8a. The structure of the obtained joined body is conductive porous body 5 / anode catalyst layer 8a / cation exchange membrane 7.

このようにして得られた導電性多孔質体５／アノード触媒層８ａ／陽イオン交換膜７接合体の陽イオン交換膜側に、カソード触媒層を接合する手順について説明する。   A procedure for joining the cathode catalyst layer to the cation exchange membrane side of the conductive porous body 5 / anode catalyst layer 8a / cation exchange membrane 7 assembly thus obtained will be described.

カソード触媒層に第１の工程で得られた第１の積層体を用いる場合、図６に断面構造を示したように、陽イオン交換膜側に、カソード触媒層／シート積層体を、カソード触媒層が陽イオン交換膜に接するように接合し、シートを剥離することによって、導電性多孔質体５／アノード触媒層８ａ／陽イオン交換膜７／カソード触媒層１ｃの四層構造の膜／電極接合体が得られる。なお、ＤＭＦＣに用いる場合、カソード触媒層１ｃには、別に導電性多孔質体を接合する必要がある。   When the first laminate obtained in the first step is used for the cathode catalyst layer, the cathode catalyst layer / sheet laminate is placed on the cation exchange membrane side as shown in FIG. The layers are bonded so as to contact the cation exchange membrane, and the sheet is peeled off, whereby a membrane / electrode having a four-layer structure of conductive porous body 5 / anode catalyst layer 8a / cation exchange membrane 7 / cathode catalyst layer 1c. A joined body is obtained. In addition, when using for DMFC, it is necessary to join a conductive porous body to the cathode catalyst layer 1c separately.

カソード触媒層に第２の工程で得られた第２の積層体を用いる場合、図７に断面構造を示したように、陽イオン交換膜側に、導電性多孔質体５／カノード触媒層４ｃの積層体を、カノード触媒層４ｃが陽イオン交換膜に接するように接合することによって、導電性多孔質体５／アノード触媒層８ａ／陽イオン交換膜７／カソード触媒層４ｃ／導電性多孔質体５の五層構造の膜／電極接合体が得られる。   When the second laminated body obtained in the second step is used for the cathode catalyst layer, the conductive porous body 5 / canode catalyst layer 4c is formed on the cation exchange membrane side as shown in the cross-sectional structure in FIG. Are joined so that the canode catalyst layer 4c is in contact with the cation exchange membrane, so that the conductive porous body 5 / the anode catalyst layer 8a / the cation exchange membrane 7 / the cathode catalyst layer 4c / the conductive porous body. A membrane / electrode assembly having a five-layer structure of the body 5 is obtained.

つぎに、第３の工程で得られたアノード触媒層１ａ／陽イオン交換膜７／カソード触媒層１ｃからなる三層構造の膜／電極接合体の両面に第２の積層体を接合する手順を説明する。   Next, a procedure for joining the second laminated body to both surfaces of the membrane / electrode assembly having a three-layer structure comprising the anode catalyst layer 1a / cation exchange membrane 7 / cathode catalyst layer 1c obtained in the third step is performed. explain.

第４の工程では、第２の積層体の触媒層が三層構造の膜／電極接合体の触媒層に接するように、第２の積層体を三層構造の膜／電極接合体の両面に接合して、導電性多孔質体／触媒層／陽イオン交換膜／触媒層／導電性多孔質体の五層構造の膜／電極接合体を製作する。   In the fourth step, the second laminate is placed on both surfaces of the three-layer membrane / electrode assembly so that the catalyst layer of the second laminate contacts the catalyst layer of the three-layer membrane / electrode assembly. The membrane / electrode assembly having a five-layer structure of conductive porous body / catalyst layer / cation exchange membrane / catalyst layer / conductive porous body is manufactured by bonding.

図８に第４の工程で得られた五層構造の膜／電極接合体の断面構造を示す。五層構造の膜／電極接合体は、第３の工程で得られたアノード触媒層１ａ／陽イオン交換膜７／カソード触媒層１ｃからなる三層構造の膜／電極接合体の両面に、第２の工程で得られた触媒層と導電性多孔質体との第２の積層体を、アノード触媒層１ａとアノード触媒層４ａとが接し、カソード触媒層１ｃとカソード触媒層４ｃとが接するように接合したものである。   FIG. 8 shows a cross-sectional structure of a five-layer membrane / electrode assembly obtained in the fourth step. The five-layer membrane / electrode assembly is formed on both surfaces of the three-layer membrane / electrode assembly comprising the anode catalyst layer 1a / cation exchange membrane 7 / cathode catalyst layer 1c obtained in the third step. In the second laminate of the catalyst layer and the conductive porous body obtained in the step 2, the anode catalyst layer 1a and the anode catalyst layer 4a are in contact with each other, and the cathode catalyst layer 1c and the cathode catalyst layer 4c are in contact with each other. It is joined.

図８に示すように、アノード触媒層１ａとアノード触媒層４ａとを合わせて1層のアノード触媒層８ａとなり、カソード触媒層１ｃとカソード触媒層４ｃとを合わせて1層のカソード触媒層８ｃとなるため、導電性多孔質体５／アノード触媒層（８ａ＝１ａ＋４ａ）／陽イオン交換膜７／カソード触媒層（８ｃ＝１ｃ＋４ｃ）／導電性多孔質体５の五層構造の膜／電極接合体が得られる。   As shown in FIG. 8, the anode catalyst layer 1a and the anode catalyst layer 4a are combined to form one anode catalyst layer 8a, and the cathode catalyst layer 1c and the cathode catalyst layer 4c are combined to form one cathode catalyst layer 8c. Therefore, a five-layer membrane / electrode assembly of conductive porous body 5 / anode catalyst layer (8a = 1a + 4a) / cation exchange membrane 7 / cathode catalyst layer (8c = 1c + 4c) / conductive porous body 5 Is obtained.

第４の工程での接合は、加熱圧着することによりおこなうことができる。加熱圧着の温度は、陽イオン交換樹脂のガラス転移温度の近傍である１２０℃以上、２００℃以下であることが好ましく、加熱圧着の圧力は５０ｋｇｆ／ｃｍ２以上、１００ｋｇｆ／ｃｍ２以下であることが好ましい。 The joining in the fourth step can be performed by thermocompression bonding. The thermocompression bonding temperature is preferably 120 ° C. or more and 200 ° C. or less, which is near the glass transition temperature of the cation exchange resin, and the thermocompression bonding pressure is 50 kgf / cm 2 or more and 100 kgf / cm 2 or less. Is preferred.

１２０℃より低い温度、あるいは５０ｋｇｆ／ｃｍ２より低い圧力の場合では、触媒層間（１ａと４ａ間および１ｃと４ｃ間）の接着が不十分になる恐れがあり、２００℃より高い温度、あるいは１００ｋｇｆ／ｃｍ２より高い圧力の場合では、陽イオン交換膜が分解、もしくは導電性多孔質体が潰れ過ぎて、燃料やガスの拡散性が低下することによって、分極特性が低下するおそれがある。さらに、加熱圧着するための装置は、第３の工程で用いたのと同じ装置を用いることができる。 In the case of a temperature lower than 120 ° C. or a pressure lower than 50 kgf / cm 2 , there is a possibility that adhesion between the catalyst layers (between 1a and 4a and between 1c and 4c) may be insufficient, and a temperature higher than 200 ° C. or 100 kgf When the pressure is higher than / cm 2 , the cation exchange membrane may be decomposed or the conductive porous body may be crushed so that the diffusibility of the fuel and gas may be reduced, thereby reducing the polarization characteristics. Furthermore, the same apparatus as used in the third step can be used as the apparatus for thermocompression bonding.

本発明の触媒層は、触媒金属材料、陽イオン交換樹脂、炭素材料などから構成されるものであり、必要に応じてＰＴＦＥやＦＥＰ（フルオロエチレンプロピレン）などの撥水性材料や結着剤を使用することもできる。   The catalyst layer of the present invention is composed of a catalytic metal material, a cation exchange resin, a carbon material, etc., and a water-repellent material such as PTFE or FEP (fluoroethylene propylene) or a binder is used as necessary. You can also

本発明で得られたＤＭＦＣ用ＭＥＡをＤＭＦＣで使用する場合には、ＭＥＡのカソードには酸素を含むガス、アノードにはメタノール水溶液が供給される。具体的には、ガスや水溶液の流路となる溝が形成されたセパレータをＭＥＡの両電極の外側に配置して、流路にガスや水溶液を流すことにより、ＭＥＡに酸素を含むガスやメタノール水溶液を供給する。   When the DMFC MEA obtained in the present invention is used in a DMFC, a gas containing oxygen is supplied to the cathode of the MEA, and an aqueous methanol solution is supplied to the anode. More specifically, a gas or aqueous solution containing oxygen or oxygen in the MEA is formed by disposing a separator formed with a groove to be a flow path for gas or aqueous solution outside both electrodes of the MEA and flowing the gas or aqueous solution through the flow path. Supply aqueous solution.

以下、好適な実施例を用いて、本発明を説明する。   Hereinafter, the present invention will be described using preferred embodiments.

［実施例１］
第１の工程では、アノード触媒層およびカソード触媒層とシートとの積層体を以下の手順で製作した。アノード触媒層用スラリーは、白金−ルテニウム触媒担持カーボン（田中貴金属工業社製、白金３０．５質量％、ルテニウム２３．５質量％）１．０ｇとスルホン酸基を有するパーフルオロカーボン重合体からなる陽イオン交換樹脂（旭化成社製、１０質量％溶液）３．３ｇと撥水剤（三井・デュポンフロロケミカル社製、ＦＥＰ、５４質量％分散液）０．５ｇと精製水８．０ｇとを秤量したのちに攪拌棒で混合し、さらに、遊星ボールミルを用いて混練することによって作製した。 [Example 1]
In the first step, an anode catalyst layer and a laminate of a cathode catalyst layer and a sheet were produced by the following procedure. The anode catalyst layer slurry is a positive electrode comprising 1.0 g of platinum-ruthenium catalyst-supporting carbon (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., 30.5 mass% platinum, 23.5 mass% ruthenium) and a perfluorocarbon polymer having a sulfonic acid group. 3.3 g of an ion exchange resin (manufactured by Asahi Kasei Corporation, 10% by weight solution), 0.5 g of a water repellent (manufactured by Mitsui DuPont Fluoro Chemical Co., FEP, 54% by weight dispersion) and 8.0 g of purified water were weighed. After that, it was prepared by mixing with a stir bar and further kneading using a planetary ball mill.

このスラリーを２００μｍの厚さのＰＴＦＥシート上にスプレー塗工機を用いて塗布・乾燥したのちに、一辺５ｃｍの正方形に切り出すことによって、アノード触媒層とシートとの積層体を得た。これを第１の積層体ａとする。この積層体上の触媒担持量は１．０ｍｇ（Ｐｔ−Ｒｕ）／ｃｍ２であった。 The slurry was applied on a PTFE sheet having a thickness of 200 μm and dried using a spray coater, and then cut into a square having a side of 5 cm to obtain a laminate of the anode catalyst layer and the sheet. This is defined as a first laminate a. The amount of catalyst supported on this laminate was 1.0 mg (Pt—Ru) / cm 2 .

また、カソード触媒層用スラリーは、白金触媒担持カーボン（田中貴金属工業社製、白金５０質量％）１．０ｇと陽イオン交換樹脂（旭化成社製、１０質量％溶液）３．６ｇと撥水剤（三井・デュポンフロロケミカル社製、ＦＥＰ、５４質量％分散液）０．５ｇと精製水８．０ｇとを秤量したのちに攪拌棒で混合し、さらに、遊星ボールミルを用いて混練することによって作製した。   The slurry for the cathode catalyst layer was 1.0 g of platinum catalyst-supported carbon (Tanaka Kikinzoku Kogyo Co., Ltd., 50% by mass of platinum), 3.6 g of cation exchange resin (Asahi Kasei Co., Ltd., 10% by mass solution) and a water repellent. (Mitsui / Dupont Fluoro Chemical Co., FEP, 54% by weight dispersion) 0.5 g and purified water 8.0 g are weighed, mixed with a stir bar, and further kneaded using a planetary ball mill. did.

このスラリーを２００μｍの厚さのＰＴＦＥシート上にスプレー塗工機を用いて塗布・乾燥したのちに、一辺５ｃｍの正方形に切り出すことによって、カソード触媒層とシートとの積層体を得た。これを第１の積層体ｃとする。この積層体上の触媒担持量は０．５ｍｇ（Ｐｔ）／ｃｍ２であった。 This slurry was applied and dried on a PTFE sheet having a thickness of 200 μm using a spray coating machine, and then cut into a square having a side of 5 cm to obtain a laminate of a cathode catalyst layer and a sheet. This is designated as a first laminate c. The amount of catalyst supported on this laminate was 0.5 mg (Pt) / cm 2 .

第２の工程では、アノード触媒層およびカソード触媒層と導電性多孔質体との積層体を以下の手順で製作した。まず、第１の工程で用いたのと同じアノード触媒層用スラリーおよびカソード触媒層用スラリーを作製した。   In the second step, a laminated body of the anode catalyst layer, the cathode catalyst layer, and the conductive porous body was manufactured by the following procedure. First, the same anode catalyst layer slurry and cathode catalyst layer slurry as used in the first step were prepared.

つぎに、一辺５ｃｍの正方形に切り出した導電性多孔質体であるカーボンペーパー（東レ社製、厚さ３００μｍ）を撥水剤（三井・デュポンフロロケミカル社製ＦＥＰ、１０質量％分散液）に含浸し、乾燥したのちに、３６０℃で焼成することによって、撥水性を施したカーボンペーパーを得た。このカーボンペーパーの片面に上記アノード触媒層用スラリーをスプレー塗工機で塗布・乾燥することによって、アノード触媒層と導電性多孔質体との積層体を得た。これを第２の積層体ａとする。この積層体上の触媒担持量は１．０ｍｇ（Ｐｔ−Ｒｕ）／ｃｍ２であった。 Next, carbon paper (made by Toray Industries, Inc., 300 μm thick), which is a conductive porous material cut into a square with a side of 5 cm, is impregnated with a water repellent (FE, 10% by mass dispersion manufactured by Mitsui DuPont Fluorochemical Co., Ltd.). And after drying, the carbon paper which gave water repellency was obtained by baking at 360 degreeC. The anode catalyst layer slurry was applied to one side of the carbon paper with a spray coater and dried to obtain a laminate of the anode catalyst layer and the conductive porous body. This is a second laminate a. The amount of catalyst supported on this laminate was 1.0 mg (Pt—Ru) / cm 2 .

上記と同様の手順で撥水性を施したカーボンペーパーの片面にカソード触媒層用スラリーをスプレー塗工機で塗布・乾燥することによって、カソード触媒層と導電性多孔質体との積層体を得た。これを第２の積層体ｃとする。この積層体上の触媒担持量は０．５ｍｇ（Ｐｔ）／ｃｍ２であった。 A cathode catalyst layer slurry and a conductive porous body laminate were obtained by applying and drying the cathode catalyst layer slurry on one side of a carbon paper that had been subjected to water repellency in the same manner as described above using a spray coating machine. . This is a second laminate c. The amount of catalyst supported on this laminate was 0.5 mg (Pt) / cm 2 .

第３の工程では、第１の工程で得られたアノード触媒層とシートとの第１の積層体（３）ａおよびカソード触媒層とシートとの第１の積層体ｃとを、スルホン酸基を有するパーフルオロカーボン重合体からなる陽イオン交換膜（ＤｕＰｏｎｔ社製、厚さ１７５μｍ）の両面に、触媒層と陽イオン交換膜とが接するように配したのちに、２００ｋｇｆ／ｃｍ２、１５０℃の条件でホットプレスすることによって、陽イオン交換膜の両面に第１の積層体ａおよび第１の積層体ｃとを一体に接合した。そのあと、この接合体からシートを剥離することによって、アノード触媒層／陽イオン交換膜／カソード触媒層が接合された三層構造のＭＥＡを得た。 In the third step, the first laminate (3) a of the anode catalyst layer and the sheet obtained in the first step and the first laminate c of the cathode catalyst layer and the sheet are converted into sulfonic acid groups. After placing the catalyst layer and the cation exchange membrane in contact with each other on both surfaces of a cation exchange membrane (made by DuPont, thickness 175 μm) made of a perfluorocarbon polymer having 200 kgf / cm 2 , 150 ° C. The first laminate a and the first laminate c were integrally bonded to both surfaces of the cation exchange membrane by hot pressing under conditions. Thereafter, the sheet was peeled from the joined body to obtain a MEA having a three-layer structure in which the anode catalyst layer / cation exchange membrane / cathode catalyst layer were joined.

第４の工程では、第２の工程で得られたアノード触媒層と導電性多孔質体との第２の積層体ａおよびカソード触媒層と導電性多孔質体との第２の積層体ｃとを、第３の工程で得られた三層構造のＭＥＡのアノード触媒層側に第２の積層体ａを配し、カソード触媒層側に第２の積層体ｃを配した。この時、三層構造のＭＥＡのアノード触媒層と第２の積層体ａのアノード触媒層が接するようにし、三層構造のＭＥＡのカソード触媒層と第２の積層体ｃのカソード触媒層が接するようにした。   In the fourth step, the second laminated body a of the anode catalyst layer and the conductive porous body obtained in the second step, and the second laminated body c of the cathode catalyst layer and the conductive porous body, The second laminate a was disposed on the anode catalyst layer side of the three-layered MEA obtained in the third step, and the second laminate c was disposed on the cathode catalyst layer side. At this time, the anode catalyst layer of the MEA having the three-layer structure is in contact with the anode catalyst layer of the second laminate a, and the cathode catalyst layer of the MEA having the three-layer structure is in contact with the cathode catalyst layer of the second laminate c. I did it.

その後、５０ｋｇｆ／ｃｍ２、１５０℃の条件でホットプレスすることによって、導電性多孔質体／アノード触媒層／陽イオン交換膜／カソード触媒層／導電性多孔質体の五層構造のＭＥＡを得た。最後に、このＭＥＡを一対の導電性フロープレートで挟持し、さらに、一対の集電板で挟持することによって、ＤＭＦＣを製作し、これを実施例１の燃料電池とした。 Thereafter, hot pressing is performed under the conditions of 50 kgf / cm 2 and 150 ° C. to obtain an MEA having a five-layer structure of conductive porous body / anode catalyst layer / cation exchange membrane / cathode catalyst layer / conductive porous body. It was. Finally, the MEFC was sandwiched between a pair of conductive flow plates and further sandwiched between a pair of current collector plates, thereby producing a DMFC. This was used as the fuel cell of Example 1.

［実施例２］
第３の工程におけるホットプレスの条件を１００ｋｇｆ／ｃｍ２、１５０℃とする以外は、実施例１と同様の手順でＭＥＡを製作した。さらに、実施例１と同様の手順でＤＭＦＣを製作し、これを実施例２の燃料電池とした。 [Example 2]
An MEA was produced in the same procedure as in Example 1 except that the hot pressing conditions in the third step were 100 kgf / cm 2 and 150 ° C. Further, a DMFC was manufactured in the same procedure as in Example 1, and this was used as the fuel cell of Example 2.

［実施例３］
第３の工程におけるホットプレスの条件を４００ｋｇｆ／ｃｍ２、１５０℃とする以外は、実施例１と同様の手順でＭＥＡを製作した。さらに、実施例１と同様の手順でＤＭＦＣを製作し、これを実施例３の燃料電池とした。 [Example 3]
An MEA was produced in the same procedure as in Example 1 except that the hot pressing conditions in the third step were 400 kgf / cm 2 and 150 ° C. Further, a DMFC was manufactured in the same procedure as in Example 1, and this was used as the fuel cell of Example 3.

［実施例４］
第４の工程におけるホットプレスの条件を７５ｋｇｆ／ｃｍ２、１５０℃とする以外は、実施例１と同様の手順でＭＥＡを製作した。さらに、実施例１と同様の手順でＤＭＦＣを製作し、これを実施例４の燃料電池とした。 [Example 4]
An MEA was produced in the same procedure as in Example 1 except that the hot pressing conditions in the fourth step were 75 kgf / cm 2 and 150 ° C. Further, a DMFC was manufactured in the same procedure as in Example 1, and this was used as the fuel cell of Example 4.

［実施例５］
第４の工程におけるホットプレスの条件を１００ｋｇｆ／ｃｍ２、１５０℃とする以外は、実施例１と同様の手順でＭＥＡを製作した。さらに、実施例１と同様の手順でＤＭＦＣを製作し、これを実施例５の燃料電池とした。 [Example 5]
An MEA was produced in the same procedure as in Example 1 except that the hot pressing conditions in the fourth step were 100 kgf / cm 2 and 150 ° C. Further, a DMFC was manufactured in the same procedure as in Example 1, and this was used as the fuel cell of Example 5.

［実施例６］
第３の工程におけるホットプレスの条件を２００ｋｇｆ／ｃｍ２、１２０℃、第４の工程におけるホットプレスの条件を５０ｋｇｆ／ｃｍ２、１５０℃とする以外は、実施例１と同様の手順でＭＥＡを製作した、さらに、実施例１と同様の手順でＤＭＦＣを製作し、これを実施例６の燃料電池をした。 [Example 6]
Except for the hot press conditions in the third step being 200 kgf / cm 2 , 120 ° C. and the hot press conditions in the fourth step being 50 kgf / cm 2 , 150 ° C., the MEA was performed in the same procedure as in Example 1. Further, a DMFC was manufactured in the same procedure as in Example 1, and this was used as the fuel cell of Example 6.

［実施例７］
第３の工程におけるホットプレスの条件を２００ｋｇｆ／ｃｍ２、２００℃、第４の工程におけるホットプレスの条件を５０ｋｇｆ／ｃｍ２、１５０℃とする以外は、実施例１と同様の手順でＭＥＡを製作した、さらに、実施例１と同様の手順でＤＭＦＣを製作し、これを実施例７の燃料電池をした。 [Example 7]
Except for the hot press conditions in the third step being 200 kgf / cm 2 and 200 ° C. and the hot press conditions in the fourth step being 50 kgf / cm 2 and 150 ° C. Further, a DMFC was manufactured in the same procedure as in Example 1, and this was used as the fuel cell of Example 7.

［実施例８］
第３の工程におけるホットプレスの条件を２００ｋｇｆ／ｃｍ２、１５０℃、第４の工程におけるホットプレスの条件を５０ｋｇｆ／ｃｍ２、１２０℃とする以外は、実施例１と同様の手順でＭＥＡを製作した、さらに、実施例１と同様の手順でＤＭＦＣを製作し、これを実施例８の燃料電池をした。 [Example 8]
Except for the hot press conditions in the third step being 200 kgf / cm 2 and 150 ° C. and the hot press conditions in the fourth step being 50 kgf / cm 2 and 120 ° C. Further, a DMFC was manufactured in the same procedure as in Example 1, and this was used as the fuel cell of Example 8.

［実施例９］
第３の工程におけるホットプレスの条件を２００ｋｇｆ／ｃｍ２、１５０℃、第４の工程におけるホットプレスの条件を５０ｋｇｆ／ｃｍ２、２００℃とする以外は、実施例１と同様の手順でＭＥＡを製作した、さらに、実施例１と同様の手順でＤＭＦＣを製作し、これを実施例９の燃料電池をした。 [Example 9]
Third 200kgf / cm 2, 150 ℃ hot pressing conditions in the process, except that the hot pressing conditions and 50kgf / cm 2, 200 ℃ in the fourth step, the MEA in the same manner as in Example 1 Further, a DMFC was manufactured in the same procedure as in Example 1, and this was used as the fuel cell of Example 9.

［実施例１０］
第３の工程におけるホットプレスの条件を２００ｋｇｆ／ｃｍ２、１２０℃、第４の工程におけるホットプレスの条件を５０ｋｇｆ／ｃｍ２、１２０℃とする以外は、実施例１と同様の手順でＭＥＡを製作した、さらに、実施例１と同様の手順でＤＭＦＣを製作し、これを実施例１０の燃料電池をした。 [Example 10]
The third condition of the hot pressing in step 200kgf / cm 2, 120 ℃, except that the hot pressing conditions and 50kgf / cm 2, 120 ℃ in the fourth step, the MEA in the same manner as in Example 1 Further, a DMFC was manufactured in the same procedure as in Example 1, and this was used as the fuel cell of Example 10.

［実施例１１］
第３の工程におけるホットプレスの条件を２００ｋｇｆ／ｃｍ２、２００℃、第４の工程におけるホットプレスの条件を５０ｋｇｆ／ｃｍ２、２００℃とする以外は、実施例１と同様の手順でＭＥＡを製作した、さらに、実施例１と同様の手順でＤＭＦＣを製作し、これを実施例１１の燃料電池をした。 [Example 11]
Third 200kgf / cm 2, 200 ℃ hot pressing conditions in the process, except that the hot pressing conditions and 50kgf / cm 2, 200 ℃ in the fourth step, the MEA in the same manner as in Example 1 Further, a DMFC was manufactured in the same procedure as in Example 1, and this was used as the fuel cell of Example 11.

［比較例１］
まず、実施例１の第１の工程で用いたのと同じアノード触媒層用スラリーおよびカソード触媒層用スラリーを作製した。そして、アノードの触媒層は以下の手順で製作した。実施例１と同様の手順で撥水性を施したカーボンペーパーの片面に上記アノード触媒層用スラリーをスプレー塗工機で塗布・乾燥することによって、アノード触媒層と導電性多孔質体との積層体を得た。この積層体上の触媒担持量は２．０ｍｇ（Ｐｔ−Ｒｕ）／ｃｍ２であった。 [Comparative Example 1]
First, the same anode catalyst layer slurry and cathode catalyst layer slurry as those used in the first step of Example 1 were prepared. The anode catalyst layer was manufactured by the following procedure. The anode catalyst layer slurry is applied and dried on one side of a carbon paper subjected to water repellency in the same procedure as in Example 1 by a spray coating machine, thereby a laminate of the anode catalyst layer and the conductive porous body. Got. The amount of catalyst supported on this laminate was 2.0 mg (Pt-Ru) / cm 2 .

つぎに、カソードの触媒層は以下の手順で製作した。実施例１と同様の手順で撥水性を施したカーボンペーパーの片面に上記カソード触媒層用スラリーをスプレー塗工機で塗布・乾燥することによって、カソード触媒層と導電性多孔質体との積層体を得た。このカソード触媒層の触媒担持量は１．０ｍｇ（Ｐｔ）／ｃｍ２であった。 Next, the catalyst layer of the cathode was manufactured by the following procedure. The cathode catalyst layer and the conductive porous body are laminated by applying and drying the cathode catalyst layer slurry on one side of a carbon paper subjected to water repellency in the same procedure as in Example 1 using a spray coating machine. Got. The amount of catalyst supported on the cathode catalyst layer was 1.0 mg (Pt) / cm 2 .

ＭＥＡは、以下の手順で製作した。スルホン酸基を有するパーフルオロカーボン重合体からなる陽イオン交換膜（ＤｕＰｏｎｔ社製、厚さ１７５μｍ）の両面にアノード触媒層およびカソード触媒層を配したのちに、１５０ｋｇｆ／ｃｍ２、１５０℃の条件でホットプレスすることによって、五層構造のＭＥＡを得た。最後に、実施例１と同様の手順でＤＭＦＣを製作し、これを比較例１の燃料電池とした。 The MEA was manufactured by the following procedure. After arranging an anode catalyst layer and a cathode catalyst layer on both sides of a cation exchange membrane (made by DuPont, thickness 175 μm) made of a perfluorocarbon polymer having a sulfonic acid group, under conditions of 150 kgf / cm 2 and 150 ° C. By hot pressing, a five-layer MEA was obtained. Finally, a DMFC was manufactured in the same procedure as in Example 1, and this was used as the fuel cell of Comparative Example 1.

［比較例２］
まず、実施例１の第１の工程で用いたのと同じアノード触媒層用スラリーおよびカソード触媒層用スラリーを作製した。そして、アノードの触媒層は以下の手順で製作した。アノード触媒層用スラリーを２００μｍの厚さのＰＴＦＥシート上にスプレー塗工機を用いて塗布・乾燥したのちに、一辺５ｃｍの正方形に切り出すことによって、アノード触媒層とシートとの積層体を得た。この積層体上の触媒担持量は２．０ｍｇ（Ｐｔ−Ｒｕ）／ｃｍ２であった。 [Comparative Example 2]
First, the same anode catalyst layer slurry and cathode catalyst layer slurry as those used in the first step of Example 1 were prepared. The anode catalyst layer was manufactured by the following procedure. The anode catalyst layer slurry was applied on a PTFE sheet having a thickness of 200 μm and dried using a spray coating machine, and then cut into a square having a side of 5 cm to obtain a laminate of the anode catalyst layer and the sheet. . The amount of catalyst supported on this laminate was 2.0 mg (Pt-Ru) / cm 2 .

つぎに、カソードの触媒層は以下の手順で製作した。カソード触媒層用スラリーを２００μｍの厚さのＰＴＦＥシート上にスプレー塗工機を用いて塗布・乾燥したのちに、一辺５ｃｍの正方形に切り出すことによって、カソード触媒層とシートとの積層体を得た。この積層体上の触媒担持量は１．０ｍｇ（Ｐｔ）／ｃｍ２であった。 Next, the catalyst layer of the cathode was manufactured by the following procedure. The cathode catalyst layer slurry was applied onto a PTFE sheet having a thickness of 200 μm using a spray coater and dried, and then cut into a square having a side of 5 cm to obtain a laminate of the cathode catalyst layer and the sheet. . The amount of the catalyst supported on this laminate was 1.0 mg (Pt) / cm 2 .

ＭＥＡは、以下の手順で製作した。上記の工程で得たアノード触媒層およびカソード触媒層とシートとの積層体を、スルホン酸基を有するパーフルオロカーボン重合体からなる陽イオン交換膜（ＤｕＰｏｎｔ社製、厚さ１７５μｍ）の両面に配したのちに、２００ｋｇｆ／ｃｍ２、１５０℃の条件でホットプレスすることによって、陽イオン交換膜と触媒層とを一体に接合した。そのあと、その接合体からシートを剥離することによって、三層構造のＭＥＡを得た。最後に、実施例１と同様の手順で得た導電性多孔質体を上記三層構造のＭＥＡの両面に配したのちに、実施例１と同様の手順でＤＭＦＣを製作し、これを比較例２の燃料電池とした。 The MEA was manufactured by the following procedure. The laminate of the anode catalyst layer and the cathode catalyst layer obtained in the above process and the sheet was disposed on both surfaces of a cation exchange membrane (DuPont, thickness: 175 μm) made of a perfluorocarbon polymer having a sulfonic acid group. Then, the cation exchange membrane and the catalyst layer were joined together by hot pressing under conditions of 200 kgf / cm 2 and 150 ° C. Thereafter, the sheet was peeled from the joined body to obtain a MEA having a three-layer structure. Finally, after arranging the conductive porous body obtained by the same procedure as in Example 1 on both sides of the MEA having the above three-layer structure, a DMFC was manufactured by the same procedure as in Example 1, and this was used as a comparative example. 2 fuel cells were obtained.

［比較例３］
ホットプレスの条件を１００ｋｇｆ／ｃｍ２、１５０℃とする以外は、比較例１と同様の手順でＭＥＡを製作した。さらに、実施例１と同様の手順でＤＭＦＣを製作し、これを比較例３の燃料電池とした。 [Comparative Example 3]
An MEA was produced in the same procedure as in Comparative Example 1 except that the hot pressing conditions were 100 kgf / cm 2 and 150 ° C. Further, a DMFC was manufactured in the same procedure as in Example 1, and this was used as a fuel cell of Comparative Example 3.

［比較例４］
ホットプレスの条件を１００ｋｇｆ／ｃｍ２、１５０℃とする以外は、比較例２と同様の手順でＭＥＡを製作した。さらに、実施例１と同様の手順でＤＭＦＣを製作し、これを比較例４の燃料電池とした。 [Comparative Example 4]
An MEA was produced in the same procedure as in Comparative Example 2 except that the hot pressing conditions were 100 kgf / cm 2 and 150 ° C. Further, a DMFC was manufactured in the same procedure as in Example 1, and this was used as the fuel cell of Comparative Example 4.

［比較例５］
ホットプレスの条件を４００ｋｇｆ／ｃｍ２、１５０℃とする以外は、比較例２と同様の手順でＭＥＡを製作した。さらに、実施例１と同様の手順でＤＭＦＣを製作し、これを比較例５の燃料電池とした。 [Comparative Example 5]
An MEA was produced in the same procedure as in Comparative Example 2 except that the hot pressing conditions were 400 kgf / cm 2 and 150 ° C. Furthermore, a DMFC was manufactured in the same procedure as in Example 1, and this was used as the fuel cell of Comparative Example 5.

実施例１〜１１および比較例１〜５で作製したＭＥＡの内容を表１にまとめた。   The contents of MEAs prepared in Examples 1 to 11 and Comparative Examples 1 to 5 are summarized in Table 1.

Figure 2007103291
セル温度が７０℃、アノード燃料が１．０ｍｏｌ／ｌメタノール水溶液、アノード燃料流量が４ｍｌ／ｍｉｎ、カソードガスが空気、カソードガス流量が５００ｍｌ／ｍｉｎの条件下で、実施例１〜１１および比較例１〜５の燃料電池を５０ｍＡ／ｃｍ２の低電流密度と３００ｍＡ／ｃｍ２の高電流密度で運転した際の、運転開始から１分目のセル電圧を測定した。実施例１〜１１および比較例１〜５の燃料電池における５０ｍＡ／ｃｍ２および３００ｍＡ／ｃｍ２で運転した際のセル電圧を表２に示す。
Figure 2007103291
 Examples 1 to 11 and Comparative Examples under the conditions of a cell temperature of 70 ° C., an anode fuel of 1.0 mol / l methanol aqueous solution, an anode fuel flow rate of 4 ml / min, a cathode gas of air, and a cathode gas flow of 500 ml / min When the fuel cells 1 to 5 were operated at a low current density of 50 mA / cm 2 and a high current density of 300 mA / cm 2 , the cell voltage at the first minute from the start of operation was measured. Table 2 shows the cell voltages when the fuel cells of Examples 1 to 11 and Comparative Examples 1 to 5 were operated at 50 mA / cm 2 and 300 mA / cm 2 .

Figure 2007103291
表２から明らかなように、実施例１〜１１における本発明の製造方法によるＭＥＡを備えたＤＭＦＣは、比較例１〜５のＤＭＦＣとくらべて、３００ｍＡ／ｃｍ２の高電流密度領域におけるセル電圧は著しく改善されていることがわかる。
Figure 2007103291
 As is apparent from Table 2, the DMFC equipped with the MEA according to the production method of the present invention in Examples 1 to 11 was higher in cell voltage in a high current density region of 300 mA / cm 2 than the DMFCs of Comparative Examples 1 to 5. It can be seen that there is a marked improvement.

［実施例１２］
第１の工程および第２の工程では、実施例１と同様にして、第１の積層体ａ、第１の積層体ｃ、第２の積層体ａおよび第２の積層体ｃを作製した。 [Example 12]
In the first step and the second step, the first laminated body a, the first laminated body c, the second laminated body a, and the second laminated body c were produced in the same manner as in Example 1.

第３の工程では、第１の工程で得られたアノード触媒層とシートとの第１の積層体ａを、スルホン酸基を有するパーフルオロカーボン重合体からなる陽イオン交換膜（ＤｕＰｏｎｔ社製、厚さ１７５μｍ）の片面に、触媒層と陽イオン交換膜とが接するように配したのちに、２００ｋｇｆ／ｃｍ２、１５０℃の条件でホットプレスして、陽イオン交換膜の片面に第１の積層体ａを一体に接合した。そのあと、この接合体からシートを剥離することによって、アノード触媒層／陽イオン交換膜が接合された二層構造のＭＥＡを得た。 In the third step, the first laminated body a of the anode catalyst layer and the sheet obtained in the first step is converted into a cation exchange membrane made of a perfluorocarbon polymer having a sulfonic acid group (manufactured by DuPont, thickness 175 μm) on one side so that the catalyst layer and the cation exchange membrane are in contact with each other, and then hot-pressed under the conditions of 200 kgf / cm 2 and 150 ° C., the first lamination on one side of the cation exchange membrane Body a was joined together. Thereafter, the sheet was peeled from the joined body to obtain a MEA having a two-layer structure in which the anode catalyst layer / cation exchange membrane was joined.

第４の工程では、第２の工程で得られたアノード触媒層と導電性多孔質体との第２の積層体ａを、第３の工程で得られた二層構造のＭＥＡのアノード触媒層側に第２の積層体ａを配した。この時、二層構造のＭＥＡのアノード触媒層と第２の積層体ａのアノード触媒層が接するようにし、導電性多孔質体５／アノード触媒層８ａ（１ａ＋４ａ）／陽イオン交換膜７からなる三層構造の膜／電極接合体を得た。   In the fourth step, the second laminated body a of the anode catalyst layer obtained in the second step and the conductive porous body is used as the anode catalyst layer of the MEA having the two-layer structure obtained in the third step. The 2nd laminated body a was distribute | arranged to the side. At this time, the anode catalyst layer of the MEA having the two-layer structure and the anode catalyst layer of the second laminate a are in contact with each other, and the conductive porous body 5 / the anode catalyst layer 8a (1a + 4a) / the cation exchange membrane 7 is formed. A three-layer membrane / electrode assembly was obtained.

カソード触媒層には、第１の工程で得られた第１の積層体を用いた。図６に断面構造を示したように、陽イオン交換膜７側に、カソード触媒層１ｃ／シート２の第１の積層体ｃを、カソード触媒層１ｃが陽イオン交換膜７に接するように接合し、シート２を剥離することによって、導電性多孔質体５／アノード触媒層８ａ（１ａ＋４ａ）／陽イオン交換膜７／カソード触媒層１ｃである四層構造の膜／電極接合体とした。   For the cathode catalyst layer, the first laminate obtained in the first step was used. As shown in the cross-sectional structure in FIG. 6, the cathode catalyst layer 1c / first laminate c of the sheet 2 is joined to the cation exchange membrane 7 side so that the cathode catalyst layer 1c is in contact with the cation exchange membrane 7. The sheet 2 was peeled off to obtain a membrane / electrode assembly having a four-layer structure of conductive porous body 5 / anode catalyst layer 8a (1a + 4a) / cation exchange membrane 7 / cathode catalyst layer 1c.

その後、カソード触媒層１ｃに導電性多孔質体を配し、５０ｋｇｆ／ｃｍ２、１５０℃の条件でホットプレスすることによって、導電性多孔質体／アノード触媒層／陽イオン交換膜／カソード触媒層／導電性多孔質体の五層構造のＭＥＡを得た。最後に、このＭＥＡを一対の導電性フロープレートで挟持し、さらに、一対の集電板で挟持することによって、ＤＭＦＣを製作し、これを実施例１２の燃料電池とした。 Thereafter, a conductive porous body is disposed on the cathode catalyst layer 1c and hot pressed under the conditions of 50 kgf / cm 2 and 150 ° C. to thereby obtain a conductive porous body / anode catalyst layer / cation exchange membrane / cathode catalyst layer. / A five-layered MEA of conductive porous material was obtained. Finally, this MEA was sandwiched between a pair of conductive flow plates, and further sandwiched between a pair of current collector plates to produce a DMFC, which was designated as the fuel cell of Example 12.

［実施例１３］
第１の工程および第２の工程では、実施例１と同様にして、第１の積層体ａ、第１の積層体ｃ、第２の積層体ａおよび第２の積層体ｃを作製した。 [Example 13]
In the first step and the second step, the first laminated body a, the first laminated body c, the second laminated body a, and the second laminated body c were produced in the same manner as in Example 1.

アノード側の構造は実施例１２と同じとした。すなわち、第３の工程および第４の工程は実施例１２と同様にして、導電性多孔質体５／アノード触媒層８ａ（１ａ＋４ａ）／陽イオン交換膜７からなる三層構造の膜／電極接合体を得た。   The structure on the anode side was the same as in Example 12. That is, the third step and the fourth step are the same as in Example 12, and a membrane / electrode junction having a three-layer structure comprising the conductive porous body 5 / the anode catalyst layer 8a (1a + 4a) / the cation exchange membrane 7 is used. Got the body.

カソード触媒層には、第２の工程で得られた第２の積層体を用いた。図７に断面構造を示したように、陽イオン交換膜７側に、導電性多孔質体５／カソード触媒層４ｃの第２の積層体を、カソード触媒層４ｃが陽イオン交換膜７に接するように接合することによって、導電性多孔質体５／アノード触媒層８ａ（１ａ＋４ａ）／陽イオン交換膜７／カソード触媒層４ｃ／導電性多孔質体５である五層構造の膜／電極接合体とした。   For the cathode catalyst layer, the second laminate obtained in the second step was used. As shown in the cross-sectional structure of FIG. 7, the second laminated body of the conductive porous body 5 / the cathode catalyst layer 4 c is in contact with the cation exchange membrane 7, and the cathode catalyst layer 4 c is in contact with the cation exchange membrane 7. By joining in this manner, a five-layer membrane / electrode assembly of conductive porous body 5 / anode catalyst layer 8a (1a + 4a) / cation exchange membrane 7 / cathode catalyst layer 4c / conductive porous body 5 It was.

その後、５０ｋｇｆ／ｃｍ２、１５０℃の条件でホットプレスすることによって、導電性多孔質体／アノード触媒層／陽イオン交換膜／カソード触媒層／導電性多孔質体の五層構造のＭＥＡを得た。最後に、このＭＥＡを一対の導電性フロープレートで挟持し、さらに、一対の集電板で挟持することによって、ＤＭＦＣを製作し、これを実施例１３の燃料電池とした。 Thereafter, hot pressing is performed under the conditions of 50 kgf / cm 2 and 150 ° C. to obtain an MEA having a five-layer structure of conductive porous body / anode catalyst layer / cation exchange membrane / cathode catalyst layer / conductive porous body. It was. Finally, the MEFC was sandwiched between a pair of conductive flow plates and further sandwiched between a pair of current collector plates, thereby producing a DMFC. This was used as a fuel cell of Example 13.

実施例１２および実施例１３の燃料電池について、実施例１と同様の条件で、５０ｍＡ／ｃｍ２の低電流密度と３００ｍＡ／ｃｍ２の高電流密度で運転した際のセル電圧を測定した。測定結果を表３に示す。 The fuel cell of Example 12 and Example 13, under the same conditions as in Example 1, the cell voltage was measured at the time of operating at a high current density of the low current density and 300 mA / cm 2 of 50 mA / cm 2. Table 3 shows the measurement results.

Figure 2007103291
表３から明らかなように、実施例１２および１３の本発明のＤＭＦＣにおける３００ｍＡ／ｃｍ２の高電流密度領域でのセル電圧は、実施例１と同程度であった。
Figure 2007103291
 As is clear from Table 3, the cell voltage in the high current density region of 300 mA / cm 2 in the DMFCs of Examples 12 and 13 of the present invention was comparable to that in Example 1.

本発明のＭＥＡは、シート上に形成した触媒層を陽イオン交換膜に接合した後、さらに導電性多孔質体上に形成した触媒層を接合することによって製作されるために、導電性多孔質体と触媒層との間、および触媒層と陽イオン交換膜との間の接触抵抗を低減されるので、分極が小さくなり、高電流密度領域におけるセル電圧が改善されたと考えられる。   The MEA of the present invention is manufactured by joining a catalyst layer formed on a sheet to a cation exchange membrane and then joining a catalyst layer formed on a conductive porous body. It is considered that the contact resistance between the body and the catalyst layer and between the catalyst layer and the cation exchange membrane is reduced, so that the polarization is reduced and the cell voltage in the high current density region is improved.

さらに、本発明のＭＥＡは、導電性多孔質体上に形成した触媒層を接合する際、陽イオン交換膜に直接接合するのではなく、あらかじめ陽イオン交換膜に形成した触媒層に接合する。触媒層同士を接合する場合、圧力を高くしなくても、十分接着できるために、導電性多孔質体を潰しすぎることなく接合することが可能であるために、アノードおよびカソードにおける燃料および空気の拡散性の低下を抑制できるので、高電流密度領域におけるセル電圧が改善されたと考えられる。   Furthermore, when joining the catalyst layer formed on the electroconductive porous body, the MEA of the present invention is not joined directly to the cation exchange membrane, but joined to the catalyst layer previously formed on the cation exchange membrane. When the catalyst layers are bonded to each other, sufficient adhesion can be achieved without increasing the pressure, so that the conductive porous body can be bonded without being crushed too much. It can be considered that the cell voltage in the high current density region has been improved because the decrease in diffusibility can be suppressed.

したがって、本発明の製造方法は、導電性多孔質体と触媒層との間、および触媒層と陽イオン交換膜との間の接触抵抗を低減し、かつアノードおよびカソードにおける燃料および空気の拡散性を向上させるために好適な方法である。   Therefore, the production method of the present invention reduces the contact resistance between the conductive porous body and the catalyst layer, and between the catalyst layer and the cation exchange membrane, and the diffusibility of fuel and air at the anode and the cathode. It is a suitable method for improving the above.

第１の工程で得られた第１の積層体３の断面構造を示す図。The figure which shows the cross-section of the 1st laminated body 3 obtained at the 1st process. 第２の工程で得られた第２の積層体６の断面構造を示す図。The figure which shows the cross-section of the 2nd laminated body 6 obtained at the 2nd process. 第１の工程で得られた第１の積層体を陽イオン交換膜の片面に接合して得られた二層構造の膜／電極接合体の断面構造を示す図。The figure which shows the cross-sectional structure of the membrane / electrode assembly of the two-layer structure obtained by joining the 1st laminated body obtained at the 1st process to the single side | surface of a cation exchange membrane. 第１の工程で得られた第１の積層体を陽イオン交換膜の両面に接合して得られた三層構造の膜／電極接合体の断面構造を示す図。The figure which shows the cross-section of the membrane / electrode assembly of the three-layer structure obtained by joining the 1st laminated body obtained at the 1st process to both surfaces of a cation exchange membrane. 二層構造の膜／電極接合体と第２の積層体とを接合したアノード側膜／電極接合体の断面構造を示す図。The figure which shows the cross-section of the anode side film | membrane / electrode assembly which joined the film | membrane / electrode assembly of 2 layer structure, and the 2nd laminated body. 導電性多孔質体５／アノード触媒層８ａ／陽イオン交換膜７接合体の陽イオン交換膜側に、カソード触媒層として第１の積層体を接合した断面構造を示す図。The figure which shows the cross-section which joined the 1st laminated body as a cathode catalyst layer to the cation exchange membrane side of the electroconductive porous body 5 / anode catalyst layer 8a / cation exchange membrane 7 assembly. 導電性多孔質体５／アノード触媒層８ａ／陽イオン交換膜７接合体の陽イオン交換膜側に、カソード触媒層として第２の積層体を接合した断面構造を示す図。The figure which shows the cross-section which joined the 2nd laminated body as a cathode catalyst layer to the cation exchange membrane side of the electroconductive porous body 5 / anode catalyst layer 8a / cation exchange membrane 7 assembly. 第２の積層体を三層構造の膜／電極接合体の両面に接合して得られた五層構造の膜／電極接合体の断面構造を示す図。The figure which shows the cross-sectional structure of the membrane / electrode assembly of a five layer structure obtained by joining the 2nd laminated body to both surfaces of the membrane / electrode assembly of a three layer structure.

符号の説明Explanation of symbols

１、４、８ 触媒層
１ａ、４ａ、８ａ アノード触媒層
１ｃ、４ｃ、８ｃ カソード触媒層
２ シート
３ 第１の積層体（３）
５ 導電性多孔質体
６ 第２の積層体（６）
７ 陽イオン交換膜 1, 4, 8 Catalyst layer 1a, 4a, 8a Anode catalyst layer 1c, 4c, 8c Cathode catalyst layer 2 Sheet 3 First laminate (3)
5 Conductive porous body 6 Second laminated body (6)
7 Cation exchange membrane

Claims (1)

炭素材料と触媒金属と陽イオン交換樹脂とを含む触媒層を陽イオン交換膜の両面に配し、さらにその外側の両面に導電性多孔質体を配した直接メタノール形燃料電池用膜／電極接合体の製造方法において、炭素材料と触媒金属と陽イオン交換樹脂とを含むスラリーをシート上に塗布・乾燥して、触媒層とシートとの第１の積層体（３）を製作する第１の工程と、炭素材料と触媒金属と陽イオン交換樹脂溶液とを含むスラリーを導電性多孔質体上に塗布・乾燥して、触媒層と導電性多孔質体との第２の積層体（６）を製作する第２の工程と、前記第１の積層体（３）の触媒層が陽イオン交換膜に接するように、前記第１の積層体（３）を陽イオン交換膜の少なくとも一方の面に接合した後、シートを剥離し、膜／電極接合体を製作する第３の工程と、前記第２の積層体（６）の触媒層が前記膜／電極接合体の触媒層に接するように、前記第２の積層体（６）を前記膜／電極接合体に接合する第４の工程を経ることを特徴とする直接メタノール形燃料電池用膜／電極接合体の製造方法。 Direct methanol fuel cell membrane / electrode bonding with a catalyst layer containing carbon material, catalytic metal, and cation exchange resin on both sides of the cation exchange membrane, and a conductive porous material on both sides of the catalyst layer In the method for producing a body, a slurry containing a carbon material, a catalyst metal, and a cation exchange resin is applied to a sheet and dried to produce a first laminate (3) of the catalyst layer and the sheet. A second laminated body (6) of the catalyst layer and the conductive porous body by applying and drying a slurry containing a process, a carbon material, a catalyst metal and a cation exchange resin solution on the conductive porous body; And at least one surface of the cation exchange membrane so that the catalyst layer of the first laminate (3) is in contact with the cation exchange membrane. After joining to the third, the sheet is peeled off, and a third process for producing a membrane / electrode assembly And the fourth laminate (6) joined to the membrane / electrode assembly so that the catalyst layer of the second laminate (6) is in contact with the catalyst layer of the membrane / electrode assembly. A process for producing a membrane / electrode assembly for a direct methanol fuel cell, characterized by undergoing the steps of:
JP2005294889A 2005-10-07 2005-10-07 Manufacturing method of membrane/electrode assembly for direct methanol fuel cell Pending JP2007103291A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009259782A (en) * 2008-03-18 2009-11-05 Toppan Printing Co Ltd Method of manufacturing membrane electrode assembly, membrane electrode assembly, and solid high polymer fuel cell
JP2016167452A (en) * 2015-03-03 2016-09-15 株式会社フジクラ Membrane electrode assembly for direct methanol fuel cell and method for manufacturing the same, direct methanol fuel cell and method for manufacturing the same, membrane electrode assembly and method for manufacturing the same, and fuel cell and method for manufacturing the same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009259782A (en) * 2008-03-18 2009-11-05 Toppan Printing Co Ltd Method of manufacturing membrane electrode assembly, membrane electrode assembly, and solid high polymer fuel cell
JP2016167452A (en) * 2015-03-03 2016-09-15 株式会社フジクラ Membrane electrode assembly for direct methanol fuel cell and method for manufacturing the same, direct methanol fuel cell and method for manufacturing the same, membrane electrode assembly and method for manufacturing the same, and fuel cell and method for manufacturing the same

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