JP2008270062A - Evaluation method and evaluation device of membrane electrode assembly for fuel cell - Google Patents

Evaluation method and evaluation device of membrane electrode assembly for fuel cell Download PDF

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JP2008270062A
JP2008270062A JP2007113735A JP2007113735A JP2008270062A JP 2008270062 A JP2008270062 A JP 2008270062A JP 2007113735 A JP2007113735 A JP 2007113735A JP 2007113735 A JP2007113735 A JP 2007113735A JP 2008270062 A JP2008270062 A JP 2008270062A
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water
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Akira Morita
亮 森田
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Toyota Motor Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an evaluation method and device capable of accurately and efficiently evaluating water migration at an interface of an electrolyte film/electrode. <P>SOLUTION: In the evaluation method of a membrane electrode assembly for a fuel cell, a water-producing electrode 2 containing catalyst having catalytic activity for reaction producing water from oxygen and hydrogen is provided on one face of an electrolyte membrane 1 while a hydrolysis electrode 3 containing catalyst having catalytic activity for decomposition reaction of water is provided on the other face, an electrolyte material and a conductive material together with the catalyst are made contained in at least either the water-producing electrode or the hydrolysis electrode, gas containing oxygen is supplied to the water-producing electrode as well as gas not containing ingredients more easily oxidized than water is supplied to the hydrolysis electrode, a voltage impressed between the water-producing electrode and the hydrolysis electrode is varied, an amount of physical change changing in accordance with voltage variation is measured, and water migration between the electrolyte membrane and the electrodes is evaluated by a magnitude of the amount of physical change. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、電解質膜−電極間の水の移動性を評価する方法及び装置に関する。   The present invention relates to a method and apparatus for evaluating the mobility of water between an electrolyte membrane and an electrode.

燃料電池は、電気的に接続された２つの電極に燃料と酸化剤を供給し、電気化学的に燃料の酸化を起こさせることで、化学エネルギーを直接電気エネルギーに変換する。火力発電とは異なり、燃料電池はカルノーサイクルの制約を受けないので、高いエネルギー変換効率を示す。燃料電池は、通常、電解質膜を一対の電極で挟持した膜・電極接合体を基本構造とする単セルを複数積層して構成されている。中でも、電解質膜として固体高分子電解質膜を用いた固体高分子電解質型燃料電池は、小型化が容易であること、低い温度で作動すること、などの利点があることから、特に携帯用、移動体用電源として注目されている。   A fuel cell directly converts chemical energy into electrical energy by supplying fuel and an oxidant to two electrically connected electrodes and causing the fuel to be oxidized electrochemically. Unlike thermal power generation, fuel cells are not subject to the Carnot cycle and thus exhibit high energy conversion efficiency. A fuel cell is usually formed by laminating a plurality of single cells having a basic structure of a membrane / electrode assembly in which an electrolyte membrane is sandwiched between a pair of electrodes. Among them, a solid polymer electrolyte fuel cell using a solid polymer electrolyte membrane as an electrolyte membrane has advantages such as being easy to downsize and operating at a low temperature. It is attracting attention as a power source for the body.

図５は、一般的な固体高分子電解質型燃料電池における単セルの一形態例を示す断面図である。単セル１００は、燃料電池用固体高分子電解質膜（以下、単に電解質膜ということがある）６の一面側に燃料極（アノード）７、及び酸化剤極（カソード）８が設けられた膜・電極接合体１１を有している。燃料極７は電解質膜６側から順に燃料極側触媒層９ａ、燃料極側ガス拡散層１０ａが積層した構成となっている。酸化剤極８も同様に電解質膜６側から順に酸化剤極側触媒層９ｂ、酸化剤極側ガス拡散層１０ｂが積層された構成となっている。   FIG. 5 is a sectional view showing an example of a single cell in a general solid polymer electrolyte fuel cell. The single cell 100 is a membrane in which a fuel electrode (anode) 7 and an oxidant electrode (cathode) 8 are provided on one surface side of a solid polymer electrolyte membrane for fuel cell (hereinafter sometimes simply referred to as an electrolyte membrane) 6. An electrode assembly 11 is provided. The fuel electrode 7 has a structure in which a fuel electrode side catalyst layer 9a and a fuel electrode side gas diffusion layer 10a are laminated in order from the electrolyte membrane 6 side. Similarly, the oxidant electrode 8 has a configuration in which an oxidant electrode side catalyst layer 9b and an oxidant electrode side gas diffusion layer 10b are sequentially laminated from the electrolyte membrane 6 side.

各触媒層９（９ａ、９ｂ）には、各電極（７，８）における電極反応に対して触媒活性を有する電極触媒が少なくとも備えられる。電極触媒としては、燃料極の燃料の酸化反応又は酸化剤極の酸化剤の還元反応に対して触媒活性を有しているものであれば、特に限定されず、例えば、白金、又はルテニウム、鉄、ニッケル、マンガン等の金属と白金との合金などが用いられている。電極触媒は、通常、カーボンブラック等の炭素粒子や炭素繊維のような導電性炭素材料、金属粒子や金属繊維等の金属材料からなる導電性粒子に担持された状態で触媒層に含有される。   Each catalyst layer 9 (9a, 9b) is provided with at least an electrode catalyst having catalytic activity for the electrode reaction in each electrode (7, 8). The electrode catalyst is not particularly limited as long as it has catalytic activity for the oxidation reaction of the fuel at the fuel electrode or the reduction reaction of the oxidant at the oxidant electrode. For example, platinum, ruthenium, iron An alloy of platinum and a metal such as nickel or manganese is used. The electrode catalyst is usually contained in the catalyst layer in a state of being supported on conductive particles made of carbon particles such as carbon black, conductive carbon materials such as carbon fibers, or metal materials such as metal particles and metal fibers.

膜・電極接合体１１は、二つのセパレータ１２ａ、１２ｂで狭持され、単セル１００が構成される。各セパレータ１２ａ、１２ｂの片面には、反応ガス（燃料ガス、酸化剤ガス）の流路を形成する溝が設けられており、これらの溝と燃料極７、酸化剤極８の外面とで燃料ガス流路１３ａ、酸化剤ガス流路１３ｂが画成されている。燃料ガス流路１３ａは、燃料極７に燃料ガス（水素を含む又は水素を発生させる気体）を供給するための流路であり、酸化剤ガス流路１３ｂは、酸化剤極８に酸化剤ガス（酸素を含む又は酸素を発生させる気体）を供給するための流路である。   The membrane / electrode assembly 11 is sandwiched between two separators 12a and 12b to form a single cell 100. On one side of each separator 12a, 12b, grooves for forming a flow path of a reactive gas (fuel gas, oxidant gas) are provided, and fuel is formed between these grooves and the outer surfaces of the fuel electrode 7 and the oxidant electrode 8. A gas flow path 13a and an oxidant gas flow path 13b are defined. The fuel gas channel 13 a is a channel for supplying fuel gas (a gas containing hydrogen or generating hydrogen) to the fuel electrode 7, and the oxidant gas channel 13 b is oxidant gas to the oxidant electrode 8. It is a flow path for supplying (a gas containing or generating oxygen).

尚、図５において、各電極（燃料極、酸化剤極）は、共に、触媒層とガス拡散層とが積層した構造を有しているが、触媒層のみからなる単層構造の他、触媒層とガス拡散層の他に機能層を設けた構造もある。   In FIG. 5, each electrode (fuel electrode, oxidant electrode) has a structure in which a catalyst layer and a gas diffusion layer are laminated. There is also a structure in which a functional layer is provided in addition to the layer and the gas diffusion layer.

固体高分子電解質型燃料電池において、アノード（燃料極）では下記（１）式の反応が進行する。
Ｈ2 → ２Ｈ+ ＋ ２ｅ- ・・・（１）
（１）式で生じる電子は、外部回路を経由し、外部の負荷で仕事をした後、カソード（酸化剤極）に到達する。そして、（１）式で生じたプロトンは、水と水和した状態で、電気浸透により固体高分子電解質膜内をアノード側からカソード側に移動する。
一方、カソードでは下記（２）式の反応が進行する。
４Ｈ+ ＋ Ｏ2 ＋ ４ｅ- → ２Ｈ2Ｏ ・・・（２） In the solid polymer electrolyte fuel cell, the reaction of the following formula (1) proceeds at the anode (fuel electrode).
H 2 → 2H + + 2e − (1)
The electrons generated by the equation (1) reach the cathode (oxidant electrode) after working with an external load via an external circuit. Then, the proton generated in the formula (1) moves in the solid polymer electrolyte membrane from the anode side to the cathode side by electroosmosis while being hydrated with water.
On the other hand, the reaction of the following formula (2) proceeds at the cathode.
4H + + O 2 + 4e − → 2H 2 O (2)

上記したように、プロトンは水分子を随伴して燃料極側から酸化剤極側へと移動する。すなわち、燃料極から酸化剤極へと効率よくプロトンが伝導され、優れた発電性能を発現する燃料電池を得るためには、膜・電極接合体内の含水量が非常に重要となってくる。一般的に、酸化剤極では、（２）式の水の生成反応が起こると共に、燃料極側からプロトンに随伴して水が移動してくるため、含水量は比較的多くなる。しかし、燃料極では、酸化剤極からの逆拡散による水の補給はあるものの、電極反応による水の生成がない上に、プロトンに随伴して酸化剤極側へと水が移動してしまうため、乾燥状態となりやすい。燃料極の乾燥は、燃料極で生成したプロトンの酸化剤極への移動を阻み、さらに電解質膜の乾燥、ひいては、燃料電池の発電性能を大きく低下させる。   As described above, protons move from the fuel electrode side to the oxidant electrode side along with water molecules. That is, in order to obtain a fuel cell in which protons are efficiently conducted from the fuel electrode to the oxidant electrode and exhibit excellent power generation performance, the water content in the membrane-electrode assembly becomes very important. In general, at the oxidizer electrode, the water generation reaction of formula (2) occurs, and water moves from the fuel electrode side along with protons, so that the water content becomes relatively large. However, in the fuel electrode, water is replenished by back diffusion from the oxidant electrode, but water is not generated by the electrode reaction, and water moves to the oxidant electrode side accompanying protons. , Easy to dry. The drying of the fuel electrode hinders the movement of protons generated at the fuel electrode to the oxidant electrode, and further drastically reduces the drying of the electrolyte membrane, and thus the power generation performance of the fuel cell.

そこで、燃料極の乾燥を防止すべく、反応ガスを加湿した状態で供給することが行われている。しかしながら、反応ガスの加湿は、加湿器等の補機を必要とし、補機の搭載や稼動のためのエネルギー、スペースを必要とするため、発電効率の観点からできるだけ反応ガスを加湿しないことが望まれている。   Therefore, in order to prevent the fuel electrode from being dried, the reaction gas is supplied in a humidified state. However, humidification of the reaction gas requires an auxiliary device such as a humidifier and requires energy and space for the installation and operation of the auxiliary device. Therefore, it is hoped that the reaction gas should not be humidified as much as possible from the viewpoint of power generation efficiency. It is rare.

反応ガスを加湿しない低加湿条件下で燃料極における乾燥を抑制するためには、酸化剤極から燃料極への水の逆拡散が重要であるが、電解質膜−電極間の界面における水移動が逆拡散の性能を大きく左右する。以上のように、優れた発電性能、特に高負荷域での高い発電性能を発現する燃料電池の開発のためには、電解質膜−電極間の水移動性が重要であり、正確に評価することが非常に重要となってくる。   In order to suppress drying at the fuel electrode under low humidification conditions where the reaction gas is not humidified, back diffusion of water from the oxidant electrode to the fuel electrode is important, but water migration at the interface between the electrolyte membrane and the electrode is difficult. Despreading performance is greatly affected. As described above, water mobility between the electrolyte membrane and the electrode is important for the development of a fuel cell that exhibits excellent power generation performance, particularly high power generation performance in a high load range, and must be evaluated accurately. Becomes very important.

特開２００２−３１３３８０号公報JP 2002-313380 A

しかしながら、従来、電解質膜−電極の界面における水移動性を正確に評価する方法は見出されていなかった。例えば、特許文献１には、電極の排水特性や電解質膜の保水性などの燃料電池の排水特性を評価する方法として、固体高分子電解質膜と電極の接合体を、前記固体高分子電解質膜と接する第１空間部を有する第１部材と前記電極と接する第２空間部を有する第２部材で狭持し、前記第１空間部に水を供給し、前記第２空間部にガスを流して、前記第１空間部から前記第２空間部に流れる水量を測定するように構成されたことを特徴とする燃料電池の排水特性評価装置と、該装置を用いた燃料電池の排水特性評価方法が記載されている。
特許文献１に記載の技術は、水の自重と前記第２空間部に流すガスによる前記電極の乾燥によって前記第１空間部から前記第２空間部に流れる水量を測定するものであり、上記作用による水の移動は少量のためその評価に多大な時間を要する。 However, conventionally, a method for accurately evaluating the water mobility at the electrolyte membrane-electrode interface has not been found. For example, in Patent Document 1, as a method for evaluating the drainage characteristics of a fuel cell, such as drainage characteristics of an electrode and water retention of an electrolyte membrane, a solid polymer electrolyte membrane-electrode assembly is used as the solid polymer electrolyte membrane. A first member having a first space portion in contact with a second member having a second space portion in contact with the electrode, water is supplied to the first space portion, and a gas is flowed to the second space portion. An apparatus for evaluating drainage characteristics of a fuel cell configured to measure an amount of water flowing from the first space to the second space, and a drainage characteristics evaluation method for a fuel cell using the apparatus Are listed.
The technique described in Patent Document 1 measures the amount of water flowing from the first space portion to the second space portion by the weight of the water and the drying of the electrode by the gas flowing in the second space portion, and the above-described action. Because of the small amount of water movement, the evaluation takes a long time.

また、燃料電池の膜・電極接合体中における水移動に関する物性としては、相対湿度が１００％以上の時の水移動係数と、相対湿度が１００％未満の時の水拡散係数の２つがあるといわれている（Journal of The Electrochemical Society,150(7)A1008 151(2)A311 151(2)A326 等参照）が、特許文献１において、前記第２空間部に流すガスが乾燥している場合、水移動係数と水拡散係数の両方の物性が区別されずに同時に測定されてしまう。
以上のように、従来の技術では、膜-電極間の水の移動性を正確に、且つ、効率よく測定することは困難であった。 In addition, there are two physical properties relating to water movement in the membrane / electrode assembly of the fuel cell: a water movement coefficient when the relative humidity is 100% or more and a water diffusion coefficient when the relative humidity is less than 100%. It is said (see Journal of The Electrochemical Society, 150 (7) A1008 151 (2) A311 151 (2) A326 etc.). The physical properties of both the water transfer coefficient and the water diffusion coefficient are measured simultaneously without distinction.
As described above, with the conventional technology, it has been difficult to accurately and efficiently measure the mobility of water between the membrane and the electrode.

本発明は上記実情を鑑みて成し遂げられたものであり、電解質膜−電極の界面における水移動性を正確に、且つ、効率よく評価することが可能な評価方法及び装置を提供することを目的とする。   The present invention has been accomplished in view of the above circumstances, and an object thereof is to provide an evaluation method and apparatus capable of accurately and efficiently evaluating the water mobility at the electrolyte membrane-electrode interface. To do.

本発明の燃料電池用膜・電極接合体の評価方法は、電解質膜の一方の面に、酸素及びプロトン（Ｈ+）から水を生成する反応に対して触媒活性を有する触媒を含む水生成電極、及び、該電解質膜の他方の面に、水を酸素及びプロトン（Ｈ+）に分解する反応に対して触媒活性を有する触媒を含む水分解電極を設け、該水生成電極及び該水分解電極の少なくとも一方には前記触媒と共に電解質材料及び導電性材料を含有させ、前記水生成電極に酸素を含有するガス及び前記水分解電極に水よりも酸化しやすい成分を含有しないガスを供給し、前記水生成電極と前記水分解電極間に印加する電圧を変化させ、前記電圧変化に応じて変化する物理変化量を測定し、該物理変化量の大小によって前記電解質膜−電極間における水の移動性を評価することを特徴とする。 The fuel cell membrane / electrode assembly evaluation method of the present invention includes a water generating electrode including a catalyst having catalytic activity for a reaction of generating water from oxygen and protons (H + ) on one surface of an electrolyte membrane. A water splitting electrode including a catalyst having catalytic activity for a reaction of decomposing water into oxygen and protons (H + ) on the other surface of the electrolyte membrane, and the water generating electrode and the water splitting electrode At least one of the above contains an electrolyte material and a conductive material together with the catalyst, and the water generating electrode is supplied with a gas containing oxygen and the water splitting electrode is supplied with a gas not containing a component that is more easily oxidized than water, The voltage applied between the water generating electrode and the water splitting electrode is changed, the physical change amount that changes according to the voltage change is measured, and the water mobility between the electrolyte membrane and the electrode is determined by the magnitude of the physical change amount. To evaluate The features.

上記のように、電解質膜の両面に水生成電極及び水分解電極を設け、該電極間の電圧を変化させることによって、該印加電圧の変化に伴う水生成電極−水分解電極間の電流値や水分解電極における酸素発生量等の物理的変化量を測定し、この結果から水生成電極及び水分解電極における電極反応の進行具合を判断することができる。水生成電極及び水分解電極における電極反応の進行具合は、水生成電極から水分解電極への水移動性が悪いと低下することから、電極反応の進行具合を調べることによって、電極間の水移動性を評価することができる。本発明によれば、水生成電極及び該水分解電極のうち少なくとも一方を、電解質材料及び導電性材料を含有させた実際の燃料電池の電極を擬似した構造とすることによって、電極間の水移動の律速段階となる、電解質材料及び導電性材料を含有する擬似電極と電解質膜との界面における水移動性を評価できる。   As described above, the water generation electrode and the water decomposition electrode are provided on both surfaces of the electrolyte membrane, and by changing the voltage between the electrodes, the current value between the water generation electrode and the water decomposition electrode accompanying the change in the applied voltage is The amount of physical change such as the amount of oxygen generated at the water splitting electrode is measured, and from this result, the progress of the electrode reaction at the water generating electrode and the water splitting electrode can be determined. Since the progress of the electrode reaction at the water generating electrode and the water splitting electrode decreases when the water mobility from the water generating electrode to the water splitting electrode is poor, the water transfer between the electrodes can be determined by examining the progress of the electrode reaction. Sex can be evaluated. According to the present invention, at least one of the water generating electrode and the water splitting electrode has a structure simulating an electrode of an actual fuel cell containing an electrolyte material and a conductive material, thereby transferring water between the electrodes. The water mobility at the interface between the pseudo electrode containing the electrolyte material and the conductive material and the electrolyte membrane can be evaluated.

前記物理変化量としては電流値等が挙げられ、前記水生成電極と前記水分解電極間に印加する電圧を変化させた時に得られる限界電流値の大小によって、前記電解質膜−電極間における水の移動性を評価することができる。   Examples of the physical change amount include a current value and the like, and the amount of water between the electrolyte membrane and the electrode depends on the magnitude of the limit current value obtained when the voltage applied between the water generating electrode and the water splitting electrode is changed. Mobility can be evaluated.

前記水生成電極及び前記水分解電極に供給されるガスを、共に相対湿度１００％以上とすることによって、評価対象である膜・電極接合体において水は液体状態で存在することとなるため、電解質膜−電極間を水が液体状態で移動する特性（水移動係数）を正確に評価することが可能となる。   Since the gas supplied to the water generating electrode and the water splitting electrode is both set to a relative humidity of 100% or more, water is present in a liquid state in the membrane / electrode assembly to be evaluated. It is possible to accurately evaluate the characteristic (water transfer coefficient) that water moves between the membrane and the electrode in a liquid state.

また、前記水生成電極及び前記水分解電極に供給されるガスのうち、少なくとも一方を相対湿度１００％未満とすることによって、評価対象である膜・電極接合体内には、水が水蒸気の状態で存在することとなるため、電解質膜−電極間を水が気体状態で移動する特性（水拡散係数）を正確に評価することが可能となる。特に、前記水生成電極及び前記水分解電極に供給されるガスを、共に相対湿度１００％未満とすることで、さらに正確な水拡散係数を評価することができる。   In addition, by setting at least one of the gases supplied to the water generating electrode and the water splitting electrode to be less than 100% relative humidity, the membrane / electrode assembly to be evaluated has water in a water vapor state. Since it exists, it becomes possible to accurately evaluate the characteristic (water diffusion coefficient) that water moves between the electrolyte membrane and the electrode in a gaseous state. In particular, by setting the gas supplied to the water generating electrode and the water splitting electrode to be less than 100% relative humidity, a more accurate water diffusion coefficient can be evaluated.

本発明の燃料電池用膜・電極接合体の評価装置は、電解質膜−電極間における水の移動性を評価する装置であって、電解質膜の一方の面に酸素及びプロトン（Ｈ+）から水を生成する反応に対して触媒活性を有する触媒を含む水生成電極、及び、他方の面に水を酸素及びプロトン（Ｈ+）に分解する反応に対して触媒活性を有する触媒を含む水分解電極を設け、該水生成電極及び該水分解電極の少なくとも一方に前記触媒と共に電解質材料及び導電性材料を含有させた膜・電極接合体を被検試料とし、該被検試料を設置する設置部と、前記被検試料の水生成電極に酸素を含有するガスを供給する手段と、前記被検試料の水分解電極に水よりも酸化しやすい成分を含有しないガスを供給する手段と、前記被検試料の水生成電極と前記水分解電極との間に電圧を印加する手段と、前記電圧の変化に応じて変化し、且つ、前記被検試料の電解質膜−電極間における水の移動性を反映する物理変化量を測定する手段と、を備えることを可能とすることを特徴とする。 An apparatus for evaluating a membrane / electrode assembly for a fuel cell according to the present invention is an apparatus for evaluating the mobility of water between an electrolyte membrane and an electrode, and water from oxygen and protons (H + ) on one surface of the electrolyte membrane. Water generating electrode including a catalyst having a catalytic activity for a reaction to generate water, and a water splitting electrode including a catalyst having a catalytic activity for a reaction to decompose water into oxygen and protons (H + ) on the other surface A membrane / electrode assembly containing an electrolyte material and a conductive material together with the catalyst in at least one of the water generating electrode and the water splitting electrode as a test sample, and an installation section for installing the test sample; Means for supplying a gas containing oxygen to the water generating electrode of the test sample; means for supplying a gas not containing a component more easily oxidized than water to the water decomposition electrode of the test sample; Sample water generating electrode and water splitting electrode Means for applying a voltage between, and means for measuring a physical change amount that changes according to the change in the voltage and reflects the mobility of water between the electrolyte membrane and the electrode of the test sample, It is possible to provide.

本発明によれば、燃料電池用膜・電極接合体の電解質膜−電極間における水移動性について、効率良く、且つ、正確に評価することが可能である。また、本発明は、電解質膜の両面に電極を備え、これら電極間に電位を印加するため、燃料電池内において膜・電極接合体がおかれる環境に近い条件で、水移動性を評価可能であるという利点もある。   According to the present invention, it is possible to efficiently and accurately evaluate the water mobility between the electrolyte membrane and the electrode of the membrane / electrode assembly for a fuel cell. In addition, since the present invention includes electrodes on both surfaces of the electrolyte membrane and applies a potential between these electrodes, water mobility can be evaluated under conditions close to the environment in which the membrane-electrode assembly is placed in the fuel cell. There is also an advantage of being.

本発明の燃料電池用膜・電極接合体の評価方法は、電解質膜の一方の面に、酸素及びプロトン（Ｈ+）から水を生成する反応に対して触媒活性を有する触媒（以下、水生成触媒ということがある）を含む水生成電極、及び、該電解質膜の他方の面に、水を酸素及びプロトン（Ｈ+）に分解する反応に対して触媒活性を有する触媒（以下、水分解触媒ということがある）を含む水分解電極を設け、該水生成電極及び該水分解電極の少なくとも一方には前記触媒と共に電解質材料及び導電性材料を含有させ、前記水生成電極に酸素を含有するガス及び前記水分解電極に水よりも酸化しやすい成分を含有しないガスを供給し、前記水生成電極と前記水分解電極間に印加する電圧を変化させ、前記電圧変化に応じて変化する物理変化量を測定し、該物理変化量の大小によって前記電解質膜−電極間における水の移動性を評価することを特徴とする。 The fuel cell membrane / electrode assembly evaluation method of the present invention comprises a catalyst having catalytic activity for the reaction of generating water from oxygen and protons (H + ) on one surface of an electrolyte membrane (hereinafter referred to as water generation). And a catalyst having catalytic activity for the reaction of decomposing water into oxygen and protons (H + ) on the other surface of the electrolyte membrane (hereinafter, referred to as a catalyst). A gas that contains an electrolyte material and a conductive material together with the catalyst in at least one of the water generation electrode and the water decomposition electrode, and the water generation electrode contains oxygen. And a gas that does not contain a component that is easier to oxidize than water to the water-splitting electrode, changes a voltage applied between the water-generating electrode and the water-splitting electrode, and changes in physical change according to the voltage change Measure the thing The electrolyte membrane by a change of magnitude - and evaluating the mobility of the water between the electrodes.

また、本発明の電解質膜の評価装置は、電解質膜−電極間における水の移動性を評価する装置であって、電解質膜の一方の面に酸素及びプロトン（Ｈ+）から水を生成する反応に対して触媒活性を有する触媒を含む水生成電極、及び、他方の面に水を酸素及びプロトン（Ｈ+）に分解する反応に対して触媒活性を有する触媒を含む水分解電極を設け、該水生成電極及び該水分解電極の少なくとも一方に前記触媒と共に電解質材料及び導電性材料を含有させた膜・電極接合体を被検試料とし、該被検試料を設置する設置部と、前記被検試料の水生成電極に酸素を含有するガスを供給する手段と、前記被検試料の水分解電極に水よりも酸化しやすい成分を含有しないガスを供給する手段と、前記被検試料の水生成電極と前記水分解電極との間に電圧を印加する手段と、前記電圧の変化に応じて変化し、且つ、前記被検試料の電解質膜−電極間における水の移動性を反映する物理変化量を測定する手段と、を備えることを可能とすることを特徴とする。 The apparatus for evaluating an electrolyte membrane of the present invention is an apparatus for evaluating the mobility of water between an electrolyte membrane and an electrode, and is a reaction for generating water from oxygen and protons (H + ) on one surface of the electrolyte membrane. A water-generating electrode containing a catalyst having catalytic activity against the water, and a water-splitting electrode containing a catalyst having catalytic activity for the reaction of decomposing water into oxygen and protons (H + ) on the other surface; A membrane / electrode assembly in which an electrolyte material and a conductive material are contained in at least one of the water generating electrode and the water splitting electrode together with the catalyst as a test sample, and an installation portion for installing the test sample; Means for supplying a gas containing oxygen to the water generating electrode of the sample; means for supplying a gas not containing a component that is more easily oxidized than water to the water splitting electrode of the test sample; and water generation of the test sample Between the electrode and the water splitting electrode. And means for measuring a physical change amount that changes according to the change of the voltage and reflects the mobility of water between the electrolyte membrane and the electrode of the test sample. It is characterized by.

以下、本発明の燃料電池用膜・電極接合体の評価方法及び評価装置について、図１及び図２を用いて説明していく。
図１は本発明の評価装置の一形態例を示す模式図、図２は本発明の評価方法の態様例を説明する概念図である。 The fuel cell membrane / electrode assembly evaluation method and evaluation apparatus of the present invention will be described below with reference to FIGS.
FIG. 1 is a schematic diagram illustrating an example of an evaluation apparatus according to the present invention, and FIG. 2 is a conceptual diagram illustrating an example of an evaluation method according to the present invention.

本発明の評価装置の構成例を示す図１において、被検試料の各電極（水分解電極、水生成電極）には、それぞれガス［水よりも酸化しやすい成分を含有しないガス（水分解側ガス）、酸素を含有するガス（酸素含有ガス）］がマスフローコントローラーにより供給される。各ガスは、加湿器により所望の相対湿度となるように加湿され、露点計によりその湿度が確認される。さらに、各ガスは、被検試料の評価条件温度にまでヒーターにて加熱されてから被検試料に供給される。また、各ガス圧は背圧弁により制御される。
被検試料の各電極にはガスを均一に供給するための多孔体及び集電体が接続されており、該集電体には、水分解電極と水生成電極間に電圧を印加及び各電極の電流値を検出するポテンショスタットが接続されている。また、被検試料は電極の積層方向に荷重が負荷されている。被検試料はヒーターによりその温度が制御できるようになっている。 In FIG. 1 showing a configuration example of the evaluation apparatus of the present invention, each electrode (water decomposition electrode, water generation electrode) of a test sample is a gas [a gas that does not contain a component that oxidizes more easily than water (water decomposition side). Gas), oxygen-containing gas (oxygen-containing gas)] is supplied by the mass flow controller. Each gas is humidified to have a desired relative humidity by a humidifier, and the humidity is confirmed by a dew point meter. Further, each gas is heated to the evaluation condition temperature of the test sample with a heater and then supplied to the test sample. Each gas pressure is controlled by a back pressure valve.
A porous body and a current collector for uniformly supplying a gas are connected to each electrode of the test sample, and a voltage is applied to the current collector between the water splitting electrode and the water generating electrode. A potentiostat for detecting the current value of is connected. Further, a load is applied to the test sample in the electrode stacking direction. The temperature of the test sample can be controlled by a heater.

図２において、電解質膜１の一方の表面には、カーボン粒子（導電性材料）に担持された白金粒子（水生成触媒）と高分子電解質（電解質材料）とを含有する水生成電極２が設けられている。さらに、水生成電極２の外側には、カーボンペーパーを構成材料として含むガス拡散層４が設けられている。ガス拡散層４は、水生成電極２の集電体として機能すると共に、水生成電極２へのガスの拡散性を確保するガス透過性を有している。
電解質膜１の他方の表面には、白金粒子からなる水分解電極３が設けられており、水分解電極３の外側には、水分解電極３の集電体として機能すると共に、水分解電極３へのガスの供給が可能なガス透過性を有する白金メッシュ５が配設されている。
水生成電極２には、ガス拡散層４を介して、酸素を含有するガスが供給され、水分解電極３には、白金メッシュ５を介して、水よりも酸化されやすい成分を含有しないガスが供給される。 In FIG. 2, a water generating electrode 2 containing platinum particles (water generating catalyst) supported on carbon particles (conductive material) and a polymer electrolyte (electrolyte material) is provided on one surface of the electrolyte membrane 1. It has been. Further, a gas diffusion layer 4 containing carbon paper as a constituent material is provided outside the water generating electrode 2. The gas diffusion layer 4 functions as a current collector for the water generating electrode 2 and has gas permeability to ensure gas diffusibility to the water generating electrode 2.
A water-splitting electrode 3 made of platinum particles is provided on the other surface of the electrolyte membrane 1, and the water-splitting electrode 3 functions outside the water-splitting electrode 3 as a current collector of the water-splitting electrode 3. A platinum mesh 5 having gas permeability capable of supplying gas to is disposed.
A gas containing oxygen is supplied to the water generating electrode 2 through the gas diffusion layer 4, and a gas not containing a component that is more easily oxidized than water is supplied to the water splitting electrode 3 through the platinum mesh 5. Supplied.

さらに、水生成電極２と水分解電極３には、水生成電極２に対して水分解電極３の電位が貴であり、水生成電極２で水の生成反応が進行し、水分解電極３で水の分解反応が進行するように外部から電位が印加される。すると、水生成電極２では、水分解電極３で生成し、電解質膜１を通って移動してきたプロトンと供給された酸素とから水が生成する水生成反応が起こり、水分解電極３では、水生成電極２で生成し、電解質膜１を通って移動してきた水の分解反応が起こる。そして、水生成電極２と水分解電極３との間に電流が流れる。   Further, the water generating electrode 2 and the water splitting electrode 3 have a noble electric potential of the water splitting electrode 3 with respect to the water generating electrode 2, and the water generating reaction proceeds in the water generating electrode 2. An electric potential is applied from the outside so that the decomposition reaction of water proceeds. Then, in the water generation electrode 2, a water generation reaction occurs in which water is generated from the protons generated by the water decomposition electrode 3 and moved through the electrolyte membrane 1 and the supplied oxygen. The decomposition reaction of the water produced by the production electrode 2 and moving through the electrolyte membrane 1 occurs. A current flows between the water generating electrode 2 and the water splitting electrode 3.

このとき、水生成電極２と水分解電極３との間に流れる電流は、水生成電極２から水分解電極３へと移動する水の量に依存する。すなわち、水生成電極２から水分解電極３へ移動する水量が多ければ電流値は大きくなり、水生成電極２から水分解電極３へ移動する水量が少なければ電流値は小さくなる。つまり、水生成電極２と水分解電極３との間に流れる電流値を測定することで、水生成電極２から水分解電極３への水移動性を評価することができる。   At this time, the current flowing between the water generating electrode 2 and the water splitting electrode 3 depends on the amount of water moving from the water generating electrode 2 to the water splitting electrode 3. That is, the current value increases if the amount of water moving from the water generating electrode 2 to the water splitting electrode 3 is large, and the current value decreases if the amount of water moving from the water generating electrode 2 to the water splitting electrode 3 is small. That is, the water mobility from the water generation electrode 2 to the water decomposition electrode 3 can be evaluated by measuring the value of the current flowing between the water generation electrode 2 and the water decomposition electrode 3.

上記したように、燃料電池の膜・電極接合体において、電極間の水移動性は電解質膜−電極間の界面における水移動が支配的である。そこで、本発明では、電解質膜の少なくとも一方の表面に、燃料電池の電解質膜−電極界面を擬似的に形成、すなわち、電解質膜の表面に、触媒と電解質材料と導電性材料とを含有する電極を形成し、該界面を介して行われる電極間の水移動性を評価する。   As described above, in the membrane / electrode assembly of the fuel cell, the water mobility between the electrodes is dominated by the water migration at the interface between the electrolyte membrane and the electrode. Therefore, in the present invention, an electrolyte membrane-electrode interface of the fuel cell is artificially formed on at least one surface of the electrolyte membrane, that is, an electrode containing a catalyst, an electrolyte material, and a conductive material on the surface of the electrolyte membrane. And the water mobility between the electrodes performed through the interface is evaluated.

ここで、膜・電極接合体における膜−電極界面の水移動性と、水生成電極−水分解電極間の電流値についてさらに詳しく説明する。
電解質膜−電極界面における水移動性は、電解質膜と電極間の接合性に依存し、電解質膜と電極間の接合性は、電解質膜を構成する電解質材料と電極を構成する電解質材料間の接着性や、電解質膜と電極の接合方法、電解質膜の表面組成等に依存する。
たとえば、水移動性の異なる２つの膜−電極接合体ａ（水移動性高）と膜−電極接合体ｂ（水移動性低）について、電解質膜の両面に設けられた電極に含まれる水量が異なり、接合体内に水の濃度勾配が形成されている場合、接合体ａは、その濃度勾配が小さくても、水分濃度が高い電極側から電極−膜界面を経て電解質膜を介し、水分濃度が低い電極側へと水が移動する。一方、接合体ｂは、接合体ａと比較してその濃度勾配が大きくならないと、水分濃度が高い電極側から低い電極側へと水が移動しない。 Here, the water mobility at the membrane-electrode interface in the membrane-electrode assembly and the current value between the water generating electrode and the water splitting electrode will be described in more detail.
The water mobility at the electrolyte membrane-electrode interface depends on the bondability between the electrolyte membrane and the electrode, and the bondability between the electrolyte membrane and the electrode depends on the adhesion between the electrolyte material constituting the electrolyte membrane and the electrolyte material constituting the electrode. It depends on the property, the joining method of the electrolyte membrane and the electrode, the surface composition of the electrolyte membrane, and the like.
For example, for two membrane-electrode assemblies a (high water mobility) and membrane-electrode assemblies b (low water mobility) having different water mobility, the amount of water contained in the electrodes provided on both surfaces of the electrolyte membrane is In contrast, when a concentration gradient of water is formed in the joined body, the joined body a has a moisture concentration from the electrode side having a high moisture concentration through the electrode-membrane interface through the electrolyte membrane even though the concentration gradient is small. Water moves to the lower electrode side. On the other hand, when the concentration gradient of the bonded body b does not become larger than that of the bonded body a, water does not move from the electrode side having a high moisture concentration to the low electrode side.

本発明の評価方法において、上記のように水移動性の異なる膜−電極界面を有する膜・電極接合体サンプルａ及びｂを評価する場合、まず、サンプルａ及びｂ共に、水生成電極と水分解電極間の印加電位を大きくしていくと、水生成電極側では、水の生成により水濃度が高くなり、一方、水分解電極側では、水の電気分解により水濃度が低下していく。すなわち、電解質膜の各表面に設けられた水分解電極と水生成電極で存在する水量に差が生じ、膜・電極接合体内に水の濃度勾配が形成される。   In the evaluation method of the present invention, when the membrane / electrode assembly samples a and b having membrane-electrode interfaces having different water mobility as described above are evaluated, first, both of the samples a and b are subjected to water generation electrodes and water decomposition. As the applied potential between the electrodes is increased, the water concentration increases due to the generation of water on the water generation electrode side, while the water concentration decreases due to the electrolysis of water on the water decomposition electrode side. That is, a difference occurs in the amount of water existing between the water splitting electrode and the water generating electrode provided on each surface of the electrolyte membrane, and a water concentration gradient is formed in the membrane / electrode assembly.

このとき、サンプルｂでは、水分解電極と水生成電極の水量の差が大きく（濃度勾配が大きく）ならないと水生成電極側から水分解電極側へと水が移動しない。このように水の濃度勾配が大きくなっている状態では、水分解電極に存在する水量は少なくなっているので、水分解電極における水分解反応が進行しにくくなり、水生成電極へのプロトン供給量が低下するため、水生成反応も進行し難くなる。その結果、水の濃度勾配がこれ以上大きくならなくなり、膜−電極界面を経て電極間を移動する水の量もこれ以上多くならないため、水分解電極と水生成電極間に流れる電流値も頭打ちとなる。つまり、印加電圧を増加させた際の限界電流値が小さくなる。   At this time, in sample b, water does not move from the water generation electrode side to the water decomposition electrode side unless the difference in the amount of water between the water decomposition electrode and the water generation electrode is large (the concentration gradient is large). In such a state where the concentration gradient of water is large, the amount of water present in the water splitting electrode is small, so that the water splitting reaction at the water splitting electrode is difficult to proceed, and the amount of proton supply to the water generating electrode is reduced. Decreases, the water generation reaction also hardly proceeds. As a result, the concentration gradient of water does not increase any more, and the amount of water that moves between the electrodes via the membrane-electrode interface does not increase any more. Become. That is, the limit current value when the applied voltage is increased is reduced.

これに対して、サンプルａでは、水分解電極と水生成電極の水量の差が小さく（濃度勾配が小さく）ても、水生成電極側から水分解電極側へとスムーズに水が移動する。そのため、水分解電極における水分解反応も円滑に進行し、これに伴い、水生成電極へのプロトン供給量も確保され、水生成反応も円滑に進行する。すなわち、膜・電極接合体ｂとは異なり、膜・電極接合体ａでは、膜の両面間で水の濃度勾配が頭打ちとならず、水分解電極と水生成電極間に流れる電流値が大きくなる余地がある。つまり、印加電圧を増加させた際の限界電流値は、サンプルｂよりもサンプルａの方が大きくなる。   On the other hand, in sample a, even if the difference in the amount of water between the water splitting electrode and the water generating electrode is small (the concentration gradient is small), water moves smoothly from the water generating electrode side to the water splitting electrode side. For this reason, the water splitting reaction at the water splitting electrode proceeds smoothly, and accordingly, the amount of proton supply to the water generating electrode is ensured, and the water generating reaction also proceeds smoothly. That is, unlike the membrane / electrode assembly b, in the membrane / electrode assembly a, the concentration gradient of water does not peak between both surfaces of the membrane, and the value of the current flowing between the water splitting electrode and the water generating electrode increases. There is room. That is, the limit current value when the applied voltage is increased is larger in the sample a than in the sample b.

従って、水分解電極と水生成電極間に印加する電圧を増加させ、これら電極間に流れる電流値を測定し、その限界電流値の大小を測定することによって、膜・電極接合体の水移動性を評価することができる。
以上のように、本発明の評価方法によれば、燃料電池を構成する電解質膜と電極に含有させる電解質材料の組み合わせの選択、電極構成材料及びその組成の選択、並びに、膜・電極間の接合方法の設定等の際、また、新規電解質膜材料の開発等の際に、膜・電極接合体の水移動性を効率よく評価することができる。さらに、後述するように、水生成電極及び水分解電極に供給するガスの湿度を適宜調整することによって、膜・電極接合体の水拡散係数や水移動係数等を正確に測定することも可能である。また、特許文献１に記載されている評価方法等と比較して、燃料電池内の作動環境に則した条件で膜・電極接合体の水移動性を評価できるという利点もある。 Therefore, by increasing the voltage applied between the water splitting electrode and the water generating electrode, measuring the current value flowing between these electrodes, and measuring the magnitude of the limit current value, the water mobility of the membrane-electrode assembly Can be evaluated.
As described above, according to the evaluation method of the present invention, the selection of the combination of the electrolyte membrane constituting the fuel cell and the electrolyte material contained in the electrode, the selection of the electrode constituent material and its composition, and the junction between the membrane and the electrode It is possible to efficiently evaluate the water mobility of the membrane / electrode assembly when setting the method or developing a new electrolyte membrane material. Furthermore, as will be described later, it is also possible to accurately measure the water diffusion coefficient, water transfer coefficient, etc. of the membrane / electrode assembly by appropriately adjusting the humidity of the gas supplied to the water generating electrode and the water splitting electrode. is there. Moreover, compared with the evaluation method etc. which are described in patent document 1, there exists an advantage that the water mobility of a membrane electrode assembly can be evaluated on the conditions according to the working environment in a fuel cell.

以下、本発明の評価方法について、さらに詳細に説明していく。
上記実施態様では、水分解電極と水生成電極間の電位変化に応じて変化する物理変化量として、水分解電極と水生成電極間に流れる電流値を例に説明してきた。しかし、該物理変化量としては、電流値に限定されず、水分解電極と水生成電極間の電位変化に応じて変化し、且つ、電解質膜・電極接合体における水の移動性を反映する物理変化量、すなわち、膜・電極接合体内を移動する水量の変化に応じて変化する物理変化量、例えば、水分解電極における酸素発生量や、水生成電極における酸素消費量等も挙げることができる。 Hereinafter, the evaluation method of the present invention will be described in more detail.
In the said embodiment, the electric current value which flows between a water splitting electrode and a water generation electrode was demonstrated to the example as a physical change amount which changes according to the electric potential change between a water splitting electrode and a water generation electrode. However, the amount of physical change is not limited to the current value, and changes depending on the potential change between the water splitting electrode and the water generating electrode, and reflects the mobility of water in the electrolyte membrane / electrode assembly. The amount of change, that is, the amount of physical change that changes in accordance with the change in the amount of water moving through the membrane-electrode assembly, for example, the amount of oxygen generated at the water splitting electrode and the amount of oxygen consumed at the water generating electrode can also be mentioned.

各電極間に印加する電圧は、水生成電極に対して水分解電極を貴電位とし、水生成電極で水の生成反応、水分解電極で水の分解反応が起こるような電位を含む範囲内で変化させればよく、具体的には、水生成電極に対する水分解電極の電圧が０．５〜３．０Ｖとなるように電圧を印加すればよい。通常、１．５Ｖ程度の電圧を印加すれば、水分解電極と接触する電解質膜表面に水はほぼ存在しなくなり、限界電流値に達すると考えられる。   The voltage applied between the electrodes is within a range including a potential at which the water splitting electrode has a noble potential with respect to the water generating electrode, and water generating reaction occurs at the water generating electrode and water splitting reaction occurs at the water splitting electrode. What is necessary is just to apply a voltage so that the voltage of the water decomposition electrode with respect to a water production | generation electrode may be set to 0.5-3.0V. Usually, if a voltage of about 1.5 V is applied, it is considered that water hardly exists on the surface of the electrolyte membrane in contact with the water-splitting electrode, and reaches the limit current value.

各電極間の電圧の制御や各電極間に流れる電流の測定は、例えば、ポテンシオスタット等を用いて行うことができる。また、上記物理変化量として酸素発生量を測定する方法としては、酸素センサー、流量計等が挙げられる。   The control of the voltage between the electrodes and the measurement of the current flowing between the electrodes can be performed using, for example, a potentiostat. Examples of the method for measuring the oxygen generation amount as the physical change amount include an oxygen sensor and a flow meter.

電解質膜としては限定されず、燃料電池を構成する電解質膜として利用可能なもの、例えば、ナフィオン（商品名）に代表されるパーフルオロカーボンスルホン酸樹脂膜等のフッ素系高分子電解質膜や、ポリエーテルエーテルケトン、ポリエーテルケトン、ポリエチレンスルフィド等の炭化水素系高分子にスルホン酸基、ボロン酸基、水酸基等のプロトン伝導性基を導入した炭化水素系高分子電解質膜等の既存の電解質膜の他、新規開発の電解質膜等を用い、評価することが可能である。   The electrolyte membrane is not limited, and can be used as an electrolyte membrane constituting a fuel cell, for example, a fluorine-based polymer electrolyte membrane such as a perfluorocarbon sulfonic acid resin membrane represented by Nafion (trade name), or a polyether. In addition to existing electrolyte membranes such as hydrocarbon polymer electrolyte membranes in which proton conducting groups such as sulfonic acid groups, boronic acid groups, and hydroxyl groups are introduced into hydrocarbon polymers such as ether ketone, polyether ketone, and polyethylene sulfide. It is possible to evaluate using a newly developed electrolyte membrane or the like.

本発明の評価方法では、電解質膜の少なくとも一方の表面に、燃料電池の膜・電極接合体を擬似する電極、すなわち、触媒と電解質材料と導電性材料を含有する電極（以下、擬似電極ということがある）が設けられていればよく、水分解電極と水生成電極が共に擬似電極であってもよいし、水分解電極と水生成電極の一方のみが擬似電極であって、他方の電極は水電解触媒又は水生成触媒のみからなる構成（図２参照）でもよい。また、水生成電極と水分解電極のうち一方のみを擬似電極とする場合には、水生成電極と水分解電極のどちらを擬似電極としてもよいが、水生成電極と電解質膜間の界面における水移動性が、膜・電極接合体の全体の水移動性に特に大きく影響するため、少なくとも水生成電極を擬似電極とすることが好ましく、特に水生成電極のみを擬似電極とすることが好ましい。   In the evaluation method of the present invention, an electrode that simulates a membrane-electrode assembly of a fuel cell, that is, an electrode containing a catalyst, an electrolyte material, and a conductive material (hereinafter referred to as a pseudo electrode) on at least one surface of the electrolyte membrane. The water splitting electrode and the water generating electrode may both be pseudo electrodes, or only one of the water splitting electrode and the water generating electrode is a pseudo electrode, and the other electrode The structure which consists only of a water electrolysis catalyst or a water production | generation catalyst (refer FIG. 2) may be sufficient. In addition, when only one of the water generating electrode and the water splitting electrode is used as a pseudo electrode, either the water generating electrode or the water splitting electrode may be used as the pseudo electrode, but water at the interface between the water generating electrode and the electrolyte membrane may be used. Since the mobility greatly affects the overall water mobility of the membrane / electrode assembly, at least the water generating electrode is preferably a pseudo electrode, and only the water generating electrode is preferably a pseudo electrode.

酸素及びプロトン（Ｈ+）から水を生成する反応（Ｏ2+４Ｈ++４ｅ-→２Ｈ2Ｏ）に対して触媒活性を有するものとしては、特に限定されず、例えば、白金や、白金−鉄、白金−コバルト、白金−イリジウム等の白金合金等を用いることができる。また、水を酸素とプロトン（Ｈ+）に分解する反応（２Ｈ2Ｏ→Ｏ2+４Ｈ++４ｅ-）に対して触媒活性を有するものとしては、特に限定されず、例えば、白金、ルテニウム、イリジウム、酸化イリジウム、酸化ルテニウム等が挙げられる。水生成触媒及び水分解触媒として利用可能な白金は、燃料電池の電極触媒としても利用されていることから、燃料電池内の作動環境により近い条件で膜−電極間の水移動性を評価できるという利点がある。 Reaction of forming water from oxygen and protons (H +) (O 2 + 4H + + 4e - → 2H 2 O) as those having a catalytic activity for not particularly limited, for example, platinum or platinum - A platinum alloy such as iron, platinum-cobalt, platinum-iridium, or the like can be used. In addition, the catalyst having a catalytic activity for the reaction (2H 2 O → O 2 + 4H + + 4e − ) that decomposes water into oxygen and protons (H + ) is not particularly limited. For example, platinum, ruthenium Iridium, iridium oxide, ruthenium oxide and the like. Platinum that can be used as a water-generating catalyst and water-splitting catalyst is also used as an electrode catalyst for fuel cells. Therefore, water mobility between membrane and electrode can be evaluated under conditions closer to the operating environment in the fuel cell. There are advantages.

電解質材料としては、特に限定されず、例えば、ナフィオン（商品名）に代表されるパーフルオロカーボンスルホン酸樹脂等のフッ素系高分子電解質や、ポリエーテルエーテルケトン、ポリエーテルケトン、ポリエチレンスルフィド等の炭化水素系高分子にスルホン酸基、ボロン酸基、水酸基等のプロトン伝導性基を導入した炭化水素系高分子電解質等の既存の電解質材料の他、新規開発の電解質材料等を用い、評価することが可能である。   The electrolyte material is not particularly limited. For example, a fluorine polymer electrolyte such as perfluorocarbon sulfonic acid resin represented by Nafion (trade name), or a hydrocarbon such as polyether ether ketone, polyether ketone, or polyethylene sulfide. In addition to existing electrolyte materials such as hydrocarbon-based polymer electrolytes in which proton-conducting groups such as sulfonic acid groups, boronic acid groups, and hydroxyl groups are introduced into polymer-based polymers, newly developed electrolyte materials can be used for evaluation. Is possible.

また、導電性材料としては、特に限定されず、導電性炭素粒子や導電性炭素繊維のほか、酸化チタン等の金属粒子や金属繊維等を用いることができる。導電性材料は、擬似電極を構成する水分解触媒又は水生成触媒を担持させた状態で電極に含有させてもよい。
擬似電極は、上記触媒、電解質材料及び導電性材料以外にも、評価したい電極構成に合わせて適宜その他の成分を含有させてよい。 Moreover, it does not specifically limit as a conductive material, In addition to conductive carbon particles and conductive carbon fibers, metal particles such as titanium oxide, metal fibers, and the like can be used. The conductive material may be contained in the electrode in a state where the water splitting catalyst or the water generating catalyst constituting the pseudo electrode is supported.
In addition to the catalyst, the electrolyte material, and the conductive material, the pseudo electrode may appropriately contain other components according to the electrode configuration to be evaluated.

水生成触媒又は水分解触媒のみからなる水生成電極又は水分解電極を形成する方法は特に限定されず、粒子状の触媒を水、エタノール等の溶媒に分散させたインクを準備し、該インクを電解質膜表面に塗布、乾燥する方法の他、メッシュ状に成形した触媒を電解質膜表面に配設する方法、スパッタ、電析めっき等が挙げられる。   There is no particular limitation on the method for forming the water generating electrode or the water splitting electrode composed of only the water generating catalyst or the water splitting catalyst. An ink in which a particulate catalyst is dispersed in a solvent such as water or ethanol is prepared, and the ink is used. In addition to the method of applying and drying on the surface of the electrolyte membrane, a method of disposing a catalyst formed in a mesh shape on the surface of the electrolyte membrane, sputtering, electrodeposition plating and the like can be mentioned.

擬似電極の形成方法は特に限定されず、例えば、触媒、導電性材料、電解質材料を溶媒に分散させたインクを準備し、該インクを電解質膜表面に塗布、乾燥する方法の他、転写基材表面に上記インクを塗布、乾燥して転写シートを作成し、電解質膜表面に転写する方法等が挙げられる。評価したい膜−電極界面の形成方法に則した方法で擬似電極を形成することでより正確な水移動性を評価することが可能となる。   The method of forming the pseudo electrode is not particularly limited. For example, in addition to a method of preparing an ink in which a catalyst, a conductive material, and an electrolyte material are dispersed in a solvent, and applying and drying the ink on the surface of the electrolyte membrane, a transfer substrate Examples include a method in which the above-mentioned ink is applied to the surface and dried to prepare a transfer sheet and transferred to the surface of the electrolyte membrane. It becomes possible to evaluate more accurate water mobility by forming the pseudo electrode by a method in accordance with the method of forming the membrane-electrode interface to be evaluated.

水生成電極及び水分解電極を設けた電解質膜は、各電極への電圧印加及び各電極間を流れる電流の測定等を効率よく行うため、さらに、集電体で狭持することが好ましい。集電体としては、導電性を有していれば特に限定されず、導電性炭素質材料からなるものや、金属材料からなるものが挙げられる。集電体は、必要に応じて、ガス流路となる溝が形成されていてもよいし、或いは、各電極へガスを均一に供給できるガス透過性を有しているものでもよい。各電極へのガスの供給を阻害しないガス透過性及び導電性を有しているものとしては、例えば、白金、金等の金属からなるメッシュ、多孔体等や、カーボンペーパー、カーボンクロス等の導電性炭素材料からなるものなどが挙げられる。擬似電極側の集電体としては、評価したい膜・電極接合体と同様の集電体（ガス拡散層）を用いることで、より正確に水移動性を評価することが可能となる。集電体は必要に応じて、適宜、撥水加工等を施してもよいし、異種材料からなる複数の層を積層した構造としてもよい。ガス透過性を有していない集電体を用いる場合には、別途ガス透過性を有する層を設けてもよい。   The electrolyte membrane provided with the water generating electrode and the water splitting electrode is preferably sandwiched by a current collector in order to efficiently apply voltage to each electrode and measure the current flowing between the electrodes. The current collector is not particularly limited as long as it has electrical conductivity, and examples thereof include those made of a conductive carbonaceous material and those made of a metal material. The current collector may be provided with a groove serving as a gas flow path, if necessary, or may have gas permeability so that gas can be uniformly supplied to each electrode. Examples of materials having gas permeability and conductivity that do not hinder the supply of gas to each electrode include, for example, meshes made of metals such as platinum and gold, porous materials, and conductive materials such as carbon paper and carbon cloth. And those made of carbonaceous materials. By using a current collector (gas diffusion layer) similar to the membrane / electrode assembly to be evaluated as the current collector on the pseudo electrode side, water mobility can be more accurately evaluated. The current collector may be appropriately subjected to water repellent treatment or the like as necessary, or may have a structure in which a plurality of layers made of different materials are laminated. In the case of using a current collector that does not have gas permeability, a layer having gas permeability may be provided separately.

集電体の厚さは、導電抵抗の観点から、５０〜４００μｍ、特に１００〜２５０μｍであることが好ましい。
尚、集電体は、水生成電極や水分解電極を触媒金属からなるメッシュ等で構成した場合等、電極自身が電圧印加や電流測定の効率的な実施を可能とする構造を有している場合には、必ずしも必要ではない。 The thickness of the current collector is preferably 50 to 400 μm, particularly preferably 100 to 250 μm from the viewpoint of conductive resistance.
The current collector has a structure that allows the electrode itself to efficiently perform voltage application and current measurement, such as when the water generating electrode and the water splitting electrode are configured with a mesh made of a catalytic metal. In some cases it is not necessary.

水生成電極に供給する酸素含有ガスは、酸素を含有するものであれば特に限定されないが、水生成電極において、膜-電極間の水移動性を効率よく評価できる程度の水生成反応が進行するように、通常は、酸素を５ｖｏｌ％以上、特に２０ｖｏｌ％以上含有するガスを用いることが好ましく、特に、純酸素ガスを用いることが好ましい。酸素以外のガス成分としては、例えば、窒素、アルゴン、ヘリウム等を含有していてもよい。   The oxygen-containing gas supplied to the water generating electrode is not particularly limited as long as it contains oxygen. However, in the water generating electrode, a water generating reaction that allows efficient evaluation of water mobility between the membrane and the electrode proceeds. Thus, usually, it is preferable to use a gas containing 5 vol% or more, particularly 20 vol% or more of oxygen, and particularly preferable to use pure oxygen gas. Examples of gas components other than oxygen may include nitrogen, argon, helium, and the like.

水分解電極に供給するガスは、評価条件において水よりも酸化しやすい成分を含有しなければ特に限定されない。評価条件において水よりも酸化しやすい成分を含有するガスを供給すると、該成分の酸化に起因する生成物や電流が測定されてしまい、水の分解による生成物や電流値を正確に測定することができなくなる。水よりも酸化しやすい成分としては、その酸化電位が水の酸化電位１．２９Ｖよりも低い成分、例えば、水素、メタン等が挙げられる。水分解電極に供給されるガスの好ましいものとしては、窒素やアルゴン等の不活性ガスが挙げられる。   The gas supplied to the water splitting electrode is not particularly limited as long as it does not contain a component that is easier to oxidize than water under the evaluation conditions. Supplying a gas containing a component that is easier to oxidize than water under the evaluation conditions, the product and current resulting from the oxidation of the component are measured, and the product and current value due to the decomposition of water must be measured accurately Can not be. Examples of components that are more easily oxidized than water include components whose oxidation potential is lower than the oxidation potential of water 1.29 V, such as hydrogen and methane. Preferable gases supplied to the water splitting electrode include inert gases such as nitrogen and argon.

各電極に供給するガスの湿度を調整することで、電解質膜の水移動性を水移動係数と水拡散係数とを区別して評価することが可能となる。
すなわち、各電極に供給するガスを共に、評価雰囲気に対して相対湿度１００％以上の状態で供給することで、電解質膜及び各電極は相対湿度が１００％以上となり、結露が生じて水が液体状態で存在する。このとき、水は電解質膜及び電極内を液体状態で移動する。このような条件下で本発明の評価を実施することによって、膜−電極界面の水移動係数を正確に測定することができる。以上のような相対湿度１００％以上の条件下での評価において、１Ａ／ｃｍ2以上の限界電流値が得られる膜・電極接合体は、水移動性に優れるものとして評価することができる。 By adjusting the humidity of the gas supplied to each electrode, the water mobility of the electrolyte membrane can be evaluated by distinguishing between the water transfer coefficient and the water diffusion coefficient.
That is, by supplying the gas supplied to each electrode in a state where the relative humidity is 100% or higher with respect to the evaluation atmosphere, the relative humidity of the electrolyte membrane and each electrode is 100% or higher, dew condensation occurs, and water is liquid. Exists in a state. At this time, water moves in a liquid state in the electrolyte membrane and the electrode. By carrying out the evaluation of the present invention under such conditions, the water transfer coefficient at the membrane-electrode interface can be accurately measured. In the above evaluation under the condition of relative humidity of 100% or more, a membrane / electrode assembly that can obtain a limit current value of 1 A / cm 2 or more can be evaluated as having excellent water mobility.

一方、各電極に供給するガスのうち、少なくとも一方を評価雰囲気に対して相対湿度１００％未満の状態で供給することで、電解質膜及び各電極は相対湿度が１００％未満となり、水が気体状態で存在する。このとき、水は接合体内を気体状態で移動する。このような条件下で本発明の評価を実施することによって、膜‐電極界面の水拡散係数を測定することができる。   On the other hand, by supplying at least one of the gases supplied to each electrode in a state where the relative humidity is less than 100% relative to the evaluation atmosphere, the relative humidity of the electrolyte membrane and each electrode is less than 100%, and water is in a gaseous state. Exists. At this time, water moves in a gaseous state in the joined body. By carrying out the evaluation of the present invention under such conditions, the water diffusion coefficient at the membrane-electrode interface can be measured.

より正確な水拡散係数を測定するためには、各電極に供給するガスの双方を相対湿度１００％未満とすることが好ましい。また、同様の観点から、評価雰囲気に対するガスの相対湿度は、６０％以下、特に３０％以下とすることが好ましい。さらに、電極に供給するガス流量を高くすることによって、電極内の相対湿度を１００％未満に保持しやすくなり、水拡散係数測定の正確性を高めることもできる。以上のような相対湿度３０％以下の条件下での評価において、０．０４Ａ／ｃｍ2以上の限界電流値が得られる膜・電極接合体は、水移動性に優れるものとして評価することができる。 In order to measure a more accurate water diffusion coefficient, it is preferable that both of the gases supplied to each electrode be less than 100% relative humidity. From the same viewpoint, the relative humidity of the gas with respect to the evaluation atmosphere is preferably 60% or less, particularly preferably 30% or less. Furthermore, by increasing the gas flow rate supplied to the electrode, the relative humidity in the electrode can be easily maintained at less than 100%, and the accuracy of water diffusion coefficient measurement can be improved. In the evaluation under the condition of the relative humidity of 30% or less as described above, the membrane / electrode assembly from which a limit current value of 0.04 A / cm 2 or more can be obtained can be evaluated as having excellent water mobility. .

上記のような相対湿度１００％以上及び相対湿度１００％未満の条件下で実施した評価結果を総合することで、高湿度条件下及び低加湿条件下における膜・電極接合体の水移動性を総合的に判断することが可能である。また、本発明の評価方法において、各電極に供給するガスの湿度は、上記１００％以上又は１００％未満という条件設定に限定されず、例えば、評価対象である膜・電極接合体の使用条件として想定される条件に合わせて適宜調節してもよい。このように使用条件に合わせて供給ガスの湿度を調節することで、使用環境下における膜・電極接合体の水移動性を評価することもできる。   By combining the evaluation results conducted under conditions of relative humidity of 100% or more and less than 100% of relative humidity as described above, the water mobility of the membrane / electrode assembly under high humidity conditions and low humidification conditions is integrated. It is possible to judge automatically. Further, in the evaluation method of the present invention, the humidity of the gas supplied to each electrode is not limited to the above condition setting of 100% or more or less than 100%. For example, as the use condition of the membrane / electrode assembly to be evaluated You may adjust suitably according to the conditions assumed. In this way, by adjusting the humidity of the supply gas in accordance with the use conditions, the water mobility of the membrane-electrode assembly in the use environment can also be evaluated.

また、燃料電池内における作動環境により近い条件で、膜・電極接合体の水移動性を評価できるという観点から、各電極の背圧を調整できるようにすることが好ましい。背圧によって、電極間の水移動性は変動するためである。電極の背圧を調整する方法としては、背圧弁等を用いる方法が挙げられる。   In addition, it is preferable that the back pressure of each electrode can be adjusted from the viewpoint that the water mobility of the membrane-electrode assembly can be evaluated under conditions closer to the operating environment in the fuel cell. This is because the water mobility between the electrodes varies depending on the back pressure. Examples of a method for adjusting the back pressure of the electrode include a method using a back pressure valve or the like.

［参考実験例１］
（評価サンプルの作製）
市販のＰｔ／Ｃ触媒（Ｐｔ担持率：６０ｗｔ％）と、電極用高分子電解質［Ｎａｆｉｏｎ、Ｄｕｐｏｎｔ製］と、溶媒（エタノール）とを、攪拌混合し、触媒インク１〜３［触媒インク１：電極用高分子電解質／カーボン（重量比）＝０．７５、触媒インク２：電極用高分子電解質／カーボン（重量比）＝０．８５、触媒インク３：電極用高分子電解質／カーボン（重量比）＝１．０］を調製した。 [Reference Experimental Example 1]
(Preparation of evaluation sample)
A commercially available Pt / C catalyst (Pt support ratio: 60 wt%), a polymer electrolyte for electrodes [Nafion, manufactured by Dupont], and a solvent (ethanol) were mixed with stirring, and catalyst inks 1 to 3 [catalyst ink 1: Polymer electrolyte for electrode / carbon (weight ratio) = 0.75, catalyst ink 2: polymer electrolyte for electrode / carbon (weight ratio) = 0.85, catalyst ink 3: polymer electrolyte for electrode / carbon (weight ratio) ) = 1.0].

得られた触媒インク１を、電解質膜の一方の面にそれぞれ塗布、乾燥し、電解質膜の表面に擬似電極（水生成電極）を形成した。電解質膜の他方の面には、白金黒を水に分散させたインクを塗布、乾燥して水分解電極を形成し、サンプル１とした。
触媒インク１の代わりに触媒インク２又は３を用いる以外はサンプル１と同様にして、サンプル２及びサンプル３を作製した。 The obtained catalyst ink 1 was applied to one surface of the electrolyte membrane and dried to form a pseudo electrode (water generating electrode) on the surface of the electrolyte membrane. On the other surface of the electrolyte membrane, an ink in which platinum black was dispersed in water was applied and dried to form a water splitting electrode.
Sample 2 and Sample 3 were prepared in the same manner as Sample 1 except that catalyst ink 2 or 3 was used instead of catalyst ink 1.

（水移動性の評価）
得られたサンプル１〜３について、以下の条件下、水分解電極に窒素ガス、水生成電極に空気を供給しながら印加電圧を変化させ、限界電流値を測定した。結果を表１及び図３に示す。 (Evaluation of water mobility)
With respect to the obtained samples 1 to 3, under the following conditions, the applied voltage was changed while supplying nitrogen gas to the water splitting electrode and air to the water generating electrode, and the limit current value was measured. The results are shown in Table 1 and FIG.

（測定条件）
評価雰囲気温度：８０℃
ガス条件［水分解電極／水生成電極］：８０℃加湿窒素／８０℃加湿空気
ガス流量［水分解電極／水生成電極］：５００ｃｃｍ／５００ｃｃｍ
印加電圧：０．５Ｖ〜２．５Ｖ（水生成電極に対して水分解電極に印加した電圧）
ガス背圧：水分解電極０ＭＰａ（Ｇ）／水生成電極０ＭＰａ（Ｇ） (Measurement condition)
Evaluation ambient temperature: 80 ° C
Gas conditions [water decomposition electrode / water generation electrode]: 80 ° C. humidified nitrogen / 80 ° C. humidified air Gas flow rate [water decomposition electrode / water generation electrode]: 500 ccm / 500 ccm
Applied voltage: 0.5 V to 2.5 V (voltage applied to the water splitting electrode with respect to the water generating electrode)
Gas back pressure: water decomposition electrode 0 MPa (G) / water generation electrode 0 MPa (G)

Figure 2008270062
Figure 2008270062

表１及び図３に示すように、電極中の電解質材料の割合の増加に伴って、限界電流値が大きくなった。これは、上記実験系においては、電解質材料／カーボン＝０．７５〜１．０の範囲において、カーボンに対する電解質材料の量が増加し、電解質膜と接触する電解質材料の量が増えることによって、電解質膜−電極間の接合性が高まり、その結果、電解質膜−電極間の水移動性が向上したためと考えられる。すなわち、本発明の評価方法によれば、燃料電池の電極における各成分の含有割合の最適化が可能であることが示された。   As shown in Table 1 and FIG. 3, the limit current value increased as the ratio of the electrolyte material in the electrode increased. This is because the amount of the electrolyte material relative to carbon increases in the range of electrolyte material / carbon = 0.75 to 1.0 and the amount of electrolyte material in contact with the electrolyte membrane increases in the above experimental system. It is considered that the bonding property between the membrane and the electrode is enhanced, and as a result, the water mobility between the electrolyte membrane and the electrode is improved. That is, according to the evaluation method of the present invention, it was shown that the content ratio of each component in the electrode of the fuel cell can be optimized.

［参考実験例２］
（評価用単セルの作製）
参考実験例１と同様にしてサンプル１を作製し、水生成電極（擬似電極）とカーボンペーパー、水分解電極と白金メッシュがそれぞれ対向するように、カーボンペーパーと白金メッシュでサンプル１を狭持して、白金メッシュ／水分解電極／電解質膜／水生成電極（擬似電極）／カーボンペーペーパーからなる膜・電極接合体１を得た。
得られた膜・電極接合体１を、２枚のセパレータ（カーボン材）で挟持し、単セル１を作製した。
サンプル１の代わりにサンプル２又は３を用いる以外は、単セル１と同様にして単セル２及び３を作製した。 [Reference Experiment Example 2]
(Production of single cell for evaluation)
Sample 1 was prepared in the same manner as in Reference Experimental Example 1, and the sample 1 was held between the carbon paper and the platinum mesh so that the water generating electrode (pseudo electrode) and the carbon paper, and the water decomposition electrode and the platinum mesh were opposed to each other. Thus, a membrane / electrode assembly 1 made of platinum mesh / water decomposition electrode / electrolyte membrane / water generation electrode (pseudo electrode) / carbon paper was obtained.
The obtained membrane / electrode assembly 1 was sandwiched between two separators (carbon materials) to produce a single cell 1.
Single cells 2 and 3 were produced in the same manner as single cell 1 except that sample 2 or 3 was used instead of sample 1.

（発電評価）
得られた単セル１〜３について、以下の条件下、発電性能評価を行った。結果を図４に示す。尚、図４において、電圧は、水分解電極に対する水生成電極の電圧が表示されている。
＜発電性能評価条件＞
セル温度：８０℃
ガス条件［燃料極／酸化剤極］：７０℃加湿水素／７０℃加湿空気
ガス流量［燃料極／酸化剤極］：５００ｃｃｍ／２０００ｃｃｍ (Power generation evaluation)
About the obtained single cells 1-3, power generation performance evaluation was performed on condition of the following. The results are shown in FIG. In FIG. 4, the voltage represents the voltage of the water generating electrode with respect to the water splitting electrode.
<Power generation performance evaluation conditions>
Cell temperature: 80 ° C
Gas condition [fuel electrode / oxidizer electrode]: 70 ° C. humidified hydrogen / 70 ° C. humidified air Gas flow rate [fuel electrode / oxidizer electrode]: 500 ccm / 2000 ccm

図４に示すように、単セル３、単セル２、単セル１の順で、全電流密度域において電圧が高く、優れた発電性能を示した。この結果は、上記サンプル１〜３の評価結果（サンプル３、サンプル２、サンプル１の順で水移動性が高い）を支持している。尚、雰囲気温度よりも各ガスの加湿温度が低いことから、本実験は、相対湿度１００％未満の条件で行われており、本実験から水拡散係数が単セル３、単セル２、単セル１の順に高いことがわかる。   As shown in FIG. 4, in the order of the single cell 3, the single cell 2, and the single cell 1, the voltage was high in the entire current density region, and excellent power generation performance was shown. This result supports the evaluation results of Samples 1 to 3 (the water mobility is higher in the order of Sample 3, Sample 2, and Sample 1). Since the humidification temperature of each gas is lower than the ambient temperature, this experiment was performed under a condition where the relative humidity was less than 100%. From this experiment, the water diffusion coefficient was single cell 3, single cell 2, single cell. It turns out that it is high in order of 1.

本発明の燃料電池用高分子電解質膜の評価装置の構成例を示す図である。It is a figure which shows the structural example of the evaluation apparatus of the polymer electrolyte membrane for fuel cells of this invention. 本発明の燃料電池用高分子電解質膜の評価方法の形態例を示す図である。It is a figure which shows the example of the form of the evaluation method of the polymer electrolyte membrane for fuel cells of this invention. 参考実験例の結果を示すグラフである。It is a graph which shows the result of a reference experiment example. 参考実験例の結果を示すグラフである。It is a graph which shows the result of a reference experiment example. 一般的な燃料電池用膜・電極接合体を含む単セルの一形態例を示す断面図である。It is sectional drawing which shows one example of a single cell containing the membrane-electrode assembly for general fuel cells.

符号の説明Explanation of symbols

１…電解質膜
２…水生成電極
３…水分解電極
４…ガス拡散層（カーボンペーパー）
５…白金メッシュ
６…電解質膜
７…燃料極（アノード）
８…酸化剤極（カソード）
９ａ…アノード側触媒層
９ｂ…カソード側触媒層
１０ａ…アノード側ガス拡散層
１０ｂ…カソード側ガス拡散層
１１…膜・電極接合体
１２ａ…アノード側セパレータ
１２ｂ…カソード側セパレータ
１３ａ…アノード側ガス流路
１３ｂ…カソード側ガス流路
１００…単セル DESCRIPTION OF SYMBOLS 1 ... Electrolyte membrane 2 ... Water generation electrode 3 ... Water decomposition electrode 4 ... Gas diffusion layer (carbon paper)
5 ... Platinum mesh 6 ... Electrolyte membrane 7 ... Fuel electrode (anode)
8 ... Oxidant electrode (cathode)
DESCRIPTION OF SYMBOLS 9a ... Anode side catalyst layer 9b ... Cathode side catalyst layer 10a ... Anode side gas diffusion layer 10b ... Cathode side gas diffusion layer 11 ... Membrane / electrode assembly 12a ... Anode side separator 12b ... Cathode side separator 13a ... Anode side gas flow path 13b ... Cathode side gas flow path 100 ... Single cell

Claims (6)

電解質膜の一方の面に、酸素及びプロトン（Ｈ+）から水を生成する反応に対して触媒活性を有する触媒を含む水生成電極、及び、該電解質膜の他方の面に、水を酸素及びプロトン（Ｈ+）に分解する反応に対して触媒活性を有する触媒を含む水分解電極を設け、該水生成電極及び該水分解電極の少なくとも一方には前記触媒と共に電解質材料及び導電性材料を含有させ、
前記水生成電極に酸素を含有するガス及び前記水分解電極に水よりも酸化しやすい成分を含有しないガスを供給し、前記水生成電極と前記水分解電極間に印加する電圧を変化させ、
前記電圧変化に応じて変化する物理変化量を測定し、該物理変化量の大小によって前記電解質膜−電極間における水の移動性を評価することを特徴とする燃料電池用膜・電極接合体の評価方法。 A water generating electrode including a catalyst having catalytic activity for a reaction for generating water from oxygen and protons (H + ) on one surface of the electrolyte membrane, and water and oxygen on the other surface of the electrolyte membrane A water-splitting electrode containing a catalyst having catalytic activity for a reaction that decomposes into protons (H + ) is provided, and at least one of the water-generating electrode and the water-splitting electrode contains an electrolyte material and a conductive material together with the catalyst Let
Supplying a gas containing oxygen to the water generating electrode and a gas not containing a component that is more easily oxidized than water to the water splitting electrode, and changing a voltage applied between the water generating electrode and the water splitting electrode;
A fuel cell membrane / electrode assembly comprising: measuring a physical change amount that varies according to the voltage change; and evaluating water mobility between the electrolyte membrane and the electrode based on the magnitude of the physical change amount. Evaluation methods. 前記物理変化量が電流値であり、前記水生成電極と前記水分解電極間に印加する電圧を変化させた時に得られる限界電流値の大小によって、前記電解質膜−電極間における水の移動性を評価する、請求項１に記載の燃料電池用膜・電極接合体の評価方法。   The physical change amount is a current value, and the mobility of water between the electrolyte membrane and the electrode is determined by the magnitude of the limit current value obtained when the voltage applied between the water generating electrode and the water splitting electrode is changed. The method for evaluating a membrane / electrode assembly for a fuel cell according to claim 1 to be evaluated. 前記水生成電極及び前記水分解電極に供給されるガスが、共に相対湿度１００％以上である、請求項１又は２に記載の燃料電池用膜・電極接合体の評価方法。   The method for evaluating a membrane / electrode assembly for a fuel cell according to claim 1 or 2, wherein both of the gas supplied to the water generating electrode and the water splitting electrode have a relative humidity of 100% or more. 前記水生成電極及び前記水分解電極に供給されるガスのうち、少なくとも一方は相対湿度が１００％未満である、請求項１又は２に記載の燃料電池用膜・電極接合体の評価方法。   The method for evaluating a membrane / electrode assembly for a fuel cell according to claim 1 or 2, wherein at least one of gases supplied to the water generating electrode and the water splitting electrode has a relative humidity of less than 100%. 前記水生成電極及び前記水分解電極に供給されるガスが、共に相対湿度１００％未満である、請求項４に記載の燃料電池用膜・電極接合体の評価方法。   The method for evaluating a membrane-electrode assembly for a fuel cell according to claim 4, wherein the gas supplied to the water generating electrode and the water splitting electrode are both less than 100% relative humidity. 電解質膜−電極間における水の移動性を評価する装置であって、
電解質膜の一方の面に酸素及びプロトン（Ｈ+）から水を生成する反応に対して触媒活性を有する触媒を含む水生成電極、及び、他方の面に水を酸素及びプロトン（Ｈ+）に分解する反応に対して触媒活性を有する触媒を含む水分解電極を設け、該水生成電極及び該水分解電極の少なくとも一方に前記触媒と共に電解質材料及び導電性材料を含有させた膜・電極接合体を被検試料とし、該被検試料を設置する設置部と、
前記被検試料の水生成電極に酸素を含有するガスを供給する手段と、
前記被検試料の水分解電極に水よりも酸化しやすい成分を含有しないガスを供給する手段と、
前記被検試料の水生成電極と前記水分解電極との間に電圧を印加する手段と、
前記電圧の変化に応じて変化し、且つ、前記被検試料の電解質膜−電極間における水の移動性を反映する物理変化量を測定する手段と、
を備えることを可能とすることを特徴とする燃料電池用膜・電極接合体の評価装置。 An apparatus for evaluating the mobility of water between an electrolyte membrane and an electrode,
A water generating electrode including a catalyst having catalytic activity for a reaction for generating water from oxygen and protons (H + ) on one side of the electrolyte membrane, and water to oxygen and protons (H + ) on the other side A membrane / electrode assembly in which a water-splitting electrode containing a catalyst having catalytic activity for a decomposition reaction is provided, and at least one of the water-generating electrode and the water-splitting electrode contains an electrolyte material and a conductive material together with the catalyst A test sample, and an installation part for installing the test sample;
Means for supplying a gas containing oxygen to the water generating electrode of the test sample;
Means for supplying a gas that does not contain a component that is more easily oxidized than water to the water-splitting electrode of the test sample;
Means for applying a voltage between the water generating electrode of the test sample and the water splitting electrode;
Means for measuring a physical change amount that changes according to a change in the voltage and reflects the mobility of water between the electrolyte membrane and the electrode of the test sample;
An apparatus for evaluating a membrane / electrode assembly for a fuel cell, comprising:
JP2007113735A 2007-04-24 2007-04-24 Evaluation method and evaluation device of membrane electrode assembly for fuel cell Pending JP2008270062A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010230339A (en) * 2009-03-26 2010-10-14 National Institute Of Advanced Industrial Science & Technology Instrument and method for separately measuring ion current or electron current of electrode material for battery
JP2013171701A (en) * 2012-02-21 2013-09-02 Nippon Soken Inc Fuel cell diagnosis device, fuel cell system, and fuel cell diagnosis method
CN115784572A (en) * 2022-12-20 2023-03-14 河北光兴半导体技术有限公司 Platinum channel and butt joint method thereof
CN115784572B (en) * 2022-12-20 2024-04-30 河北光兴半导体技术有限公司 Platinum channel and butt joint method thereof

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010230339A (en) * 2009-03-26 2010-10-14 National Institute Of Advanced Industrial Science & Technology Instrument and method for separately measuring ion current or electron current of electrode material for battery
JP2013171701A (en) * 2012-02-21 2013-09-02 Nippon Soken Inc Fuel cell diagnosis device, fuel cell system, and fuel cell diagnosis method
CN115784572A (en) * 2022-12-20 2023-03-14 河北光兴半导体技术有限公司 Platinum channel and butt joint method thereof
CN115784572B (en) * 2022-12-20 2024-04-30 河北光兴半导体技术有限公司 Platinum channel and butt joint method thereof

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