JP4062755B2 - Method for producing solid polymer electrolyte membrane - Google Patents
Method for producing solid polymer electrolyte membrane Download PDFInfo
- Publication number
- JP4062755B2 JP4062755B2 JP32660197A JP32660197A JP4062755B2 JP 4062755 B2 JP4062755 B2 JP 4062755B2 JP 32660197 A JP32660197 A JP 32660197A JP 32660197 A JP32660197 A JP 32660197A JP 4062755 B2 JP4062755 B2 JP 4062755B2
- Authority
- JP
- Japan
- Prior art keywords
- polymer electrolyte
- solid polymer
- electrolyte membrane
- membrane
- contact
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Landscapes
- Graft Or Block Polymers (AREA)
- Fuel Cell (AREA)
Description
【０００１】
【産業上の利用分野】
本発明は固体高分子電解質型燃料電池に使用する固体高分子電解質膜の製造方法に関する。
【０００２】
【従来の技術】
固体高分子電解質燃料電池は、水素及び酸素を燃料とする小型軽量電源として自動車その他への応用が有力視されている。かかる電池はイオン交換能を有する固体高分子電解質膜とこの両側に接触して配置される正極及び負極から構成される。燃料の水素は負極において電気化学的に酸化され、プロトンと電子を生成する。このプロトンは高分子電解質膜内を酸素が供給される正極に移動する。一方負極で生成した電子は電池に接続された負荷を通り、正極に流れ、正極においてプロトンと酸素と電子が反応して水を生成する。
【０００３】
このように、自動車用電力源として固体高分子電解質型燃料電池が低温作動性や小型で高出力密度であることからこのタイプの型の研究が行われているが、一般には燃料電池用高分子電解質膜としてスルホン酸基を有するパーフルオロカーボン重合体膜（商品名；ナフィオン、デュポン株式会社、商品名；アシプレックス、旭化成株式会社）等が用いられている。しかしながら、燃料電池のより高出力化からするとまだ十分なものとはいえない。
【０００４】
ここで、電池の出力向上には高分子電解質膜の水素イオン伝導性を高くし膜の内部抵抗を小さくする必要がある。この方法には高分子電解質膜のイオン交換基（例えばスルホン酸基）濃度の増大と膜厚の低減がある。しかし、イオン交換基の著しい増加は膜の含水率を必要以上に増やすため、燃料電池反応で水が生成する正極側で電極が湿りすぎることに起因する出力低下等の問題がある。
【０００５】
一方、膜厚の減少は膜の機械的強度を低下させたり、燃料である水素ガスや酸素ガスの膜透過量が増えることによって起こる電池出力効率の低下等の問題がある。
【０００６】
従来技術の文献として、特開平６−２３１７８１号公報がある。この文献は低い電気抵抗を有するために、異なる含水率を有する少なくとも２層以上のスルホン酸基を有するパーフルオロカーボン重合体フィルムの積層体からなる陽イオン交換膜を固体電解質とするものである。さらに正極側から負極側に渡って順次含水率の高い重合体フィルムを積層した構造の高分子電解質型燃料電池である。
【０００７】
また他の従来技術として、特開平６−２３１７８２号公報は、低い電気抵抗を有するために、正極に面する側のフィルムの含水率が負極に面する側のフィルムのそれよれも大きいもので、異なる含水率を有する少なくとも２層以上のスルホン酸基を有するパーフルオロカーボン重合体フィルムの積層体からなる高分子電解質型燃料電池がある。
【０００８】
【発明が解決しようとする課題】
しかしながら、前者は、積層境界前後で含水率が大きく異なるため境界付近に応力が発生し機械的な耐久性を低下させる。また、フィルムの積層による含水率の不連続変化によって、負極の含水率減少を補うために起こる正極からの水の逆拡散が効率的に行えないために、大きな出力の増大が望めない。また後者は、正極の湿りすぎと負極の高抵抗により電池出力の増加は期待できない。
【０００９】
ここで、電池の出力増加には高分子電解質膜の水素イオン伝導性を高くし膜の内部抵抗を小さくする必要がある。これには膜中のイオン交換基（例えばスルホン酸基）量と含水率が大きく関与しており、高イオン交換基量で高含水率ほど水素イオン伝導性は高くなる。
【００１０】
燃料電池の負極側では水素ガスからできた水素イオンが数個の水分子を引き連れて高分子電解質膜中を通り正極側へと伝導するため、膜の負極に接する側は相対的に含水率が下がり出力低下の原因となる。一方、正極に接する側では燃料電池反応で水が生成するため水が過剰に存在する傾向となり、水が触媒を覆いガスの拡散を阻害し出力低下の原因となると推測される。
【００１１】
そこで、本発明は、含水率が厚さ方向に均一でなく厚さ方向で連続的に変化し、かつ負極に接する側の含水率が最も高く、正極に接する側のそれが最も低く結果として膜表面が撥水性となることにより、負極の含水率減少を補うために起こる正極からの水の逆拡散が効率的に起こり、かつ正極の湿りすぎを防ぎ効率的な触媒作用が可能となり、燃料電池の高出力化が可能な固体高分子電解質型燃料電池を提供するものである。
【００２１】
本発明の請求項１において講じた技術的手段（以下、第１の技術的手段と称する。）は、
固体高分子電解質型燃料電池に使用する水素イオン伝導性を有する固体高分子電解質膜の製造方法であって、
前記固体高分子電解質膜の前駆体膜を反応液に接触させることによりイオン交換基量を変化させる工程で、前記前駆体膜の一方面からのみイオン交換基量を変化させる成分を接触させることを特徴とする固体高分子電解質膜の製造方法である。
本発明の請求項２において講じた技術的手段（以下、第２の技術的手段と称する。）は、
固体高分子電解質型燃料電池に使用する水素イオン伝導性を有する固体高分子電解質膜の製造方法であって、
前記固体高分子電解質膜の前駆体膜を反応液に接触させることにより架橋度を変化させる工程で、前記前駆体膜の一方面からのみ架橋度を変化させる成分を接触させることを特徴とする固体高分子電解質膜の製造方法である。
固体高分子電解質膜の一方面に接する負極と、他方面に接する正極とを備えることにより固体高分子電解質型燃料電池が形成される。イオン交換容量で固体高分子電解質膜の含水率が調整される。また架橋度で固体高分子電解質膜の含水率が調整される。上記した第１の技術的手段や第２の技術的手段によって製造された固体高分子電解質膜を使って、固体高分子電解質膜の含水率が、固体高分子電解質膜の厚さ方向に対し負極に接する側から正極に接する側にかけて連続的に低くなるように変化している固体高分子電解質型燃料電池が製造できる。
固体高分子電解質膜の負極に接する側の含水率が、正極に接する側の含水率よりも少なくとも５重量％以上大であることが望ましい。含水率が５重量％よりも小さいと正極から負極への水の逆拡散が効率的に行われない。
固体高分子電解質膜の負極に接する側から正極に接する側にかけて含水率が、固体高分子電解質膜の厚さ方向に対し連続的に３０〜２００重量％の範囲で変化していることが望ましい。含水率が３０重量％よりも小さいと膜の内部抵抗が高くなり、２００重量％よりも大きいと膜自身が機械強度的に硬く脆くなる。
固体高分子電解質膜が、炭化フッ素系ビニルモノマと炭化水素系ビニルモノマとの共重合体で形成させた主鎖とスルホン酸基を有する炭化水素系側鎖との共重合体からなることが望ましい。固体高分子電解質膜が、オレフィンパーフルオロカーボンとオレフィン炭化水素との共重合体で形成させた主鎖と、スルホン酸基を有するオレフィン炭化水素とジオレフィン炭化水素との架橋共重合体の側鎖との共重合体からなることがさらに望ましい。
【００２２】
高分子電解質膜の含水率を厚さ方向で連続的に変化させるには、膜中のイオン交換基量や架橋度を連続的に変化させることによって得られる。その製造方法としては、高分子電解質膜がオレフィンパーフルオロカーボンとオレフィン炭化水素との共重合体で形成させた主鎖と、スルホン酸基を有するオレフィン炭化水素とジオレフィン炭化水素との架橋共重合体の側鎖とからなる共重合体である場合には、側鎖自身や側鎖に着けるスルホン酸基の濃度を膜の厚さ方向に変化させることによって、またはジオレフィン炭化水素による架橋度を変化させることによって得ることができる。
【００２３】
具体的には、主鎖共重合体フィルムに側鎖を導入する時にフィルムの片面からのみ側鎖合成原料または架橋形成原料を接触させることによって側鎖自身の濃度または架橋度を、または側鎖にスルホン基を導入する時にフィルムの片面からのみスルホン化剤を接触させることによってスルホン酸基の濃度を膜厚方向に連続的に変化させて作製できる。
【００２４】
なお、本発明で重合体フィルム（酸型）の含水率はΔＷは以下のように定義される。
【００２５】
ΔＷ＝（Ｗ1 ／Ｗ2 −１）×１００（重量％）
Ｗ1 ：８０°Ｃ、純粋中、３時間浸漬後の膜重量。
【００２６】
Ｗ2 ：Ｗ1 を測定後、１００°Ｃにて２４時間真空乾燥した後の重量。
【００２７】
【作用】
本発明のように含水率が厚さ方向に均一でなく厚さ方向で連続的に変化し、かつ負極に接する側の含水率が最も高く、正極に接する側のそれが最も低く結果として膜表面が撥水性となることにより、負極の含水率減少を補うために起こる正極からの水の逆拡散が効率的に起こり、かつ正極の湿りすぎを防ぎ効率的な触媒作用が可能となり、結果として燃料電池の高出力化が可能となると考えられる。
【００２８】
【発明の実施の形態】
以下、本発明の実施例について、説明する。
【００２９】
（実施例１）
エチレン−四フッ化エチレン共重合体フィルム（膜厚５０μm ）に１０ｋＧｙの線量のγ線を空気中、常温下で照射した後、フィルムの片面はスチレン１００容量部とキシレン２０容量部の混合液と他面はキシレンと接するようにし６０℃で２時間グラフト反応を行った。乾燥後のフィルムの両面をクロルスルホン酸５容積部と１，２−ジクロロエタン６０容積部の混合液と常温で１時間接触させることによりスルホン化反応を行った。乾燥後、１Ｎ苛性カリ中で加水分解を行い、続いて１Ｎ塩酸中に浸漬した。次に９０℃の水で１時間洗浄した。この固体高分子電解質膜はイオン交換容量が１. ６９ミリ当量／ｇ、８０℃での含水率が７１重量％であった。膜表面の水の接触角はグラフト反応でスチレンと接触していた側が３０°、キシレン側が７２°であった（エチレン−四フッ化エチレン共重合体フィルムのそれは１１０°である）。水の接触角の低下はスルホン酸基が多く親水性に変わったことを表している。また、グラフト反応でスチレン１００容量部とキシレン２０容量部の混合液に２５μm のγ線照射フィルムを接触させそれ以降は前述と同じ工程で作製した膜のイオン交換容量は１. ８０ミリ当量／ｇ、８０℃での含水率は８６重量％であった。このことからできた固体高分子電解質膜の含水率は片面を大凡８６重量％で最高とし膜厚方向に連続的に減少していることがわかる。
【００３０】
市販のカーボンペーパにテフロンディスパージョンを塗布した後、焼成して撥水化処理を行い、この片面上に市販の白金担持カーボン（白金重量４０％）と市販ナフィオン溶液とイソプロパノールの混合物を白金量として０. ３５ｍｇ／ｃｍ２となるように塗布してガス拡散電極を作製した。
【００３１】
このガス拡散電極を正極及び負極として固体高分子電解質膜をホットプレスにより接合して燃料電池を形成した。水素圧力２. ５気圧（利用率８０％）、空気圧力２. ５気圧（利用率４０％）、電池温度８０℃においてＶ−Ｉ特性を測定した。その結果、電流密度１Ａ／ｃｍ２で出力電圧は０. ５２Ｖであった。
【００３２】
（実施例２）
グラフト反応をスチレン１００容積部とキシレン３０容積部の混合液と、スチレン９５容積部、ジビニルベンゼン５容積部、キシレン３０容積部の混合液とで行うこと以外の他の処理工程は実施例１と同様として固体高分子電解質膜を得た。この膜はイオン交換容量が１. ６３ミリ当量／ｇ、８０℃での含水率が６９重量％であった。膜表面の水の接触角はジビニルベンゼンを含む反応混合液と接触していた側が５２°、ジビニルベンゼンを含まない反応混合液と接触していた側が３３°であった。また、グラフト反応での２種類の反応混合液中で作製した電解質膜のイオン交換容量と８０℃での含水率は、ジビニルベンゼンを含む反応混合液で作製した膜の方が１. ７２ミリ当量／ｇと６１重量％であり、ジビニルベンゼンを含まない反応混合液で作製した膜の方が１. ７４ミリ当量／ｇと７８重量％であった。このことからできた固体高分子電解質膜の含水率は膜厚方向に大凡６１〜７８重量％で連続的に変化していることがわかる。
【００３３】
実施例１と同じガス拡散電極で燃料電池を形成し、同条件でＶ−Ｉ特性を測定した。その結果、電流密度１Ａ／ｃｍ２で出力電圧は０. ５０Ｖであった。
【００３４】
（実施例３）
フィルムの両面がスチレン１００容積部、キシレン３０容積部の混合液と接するようにし６０℃で２時間グラフト反応を行った後の乾燥フィルムの片面をクロルスルホン酸５容積部と１，２−ジクロロエタン６０容積部の混合液と、他面を１，２−ジクロロエタンのみと接するようにし４０℃で１時間スルホン化反応を行った。この２反応以外は実施例１と同様の処理工程を行い固体高分子電解質膜を得た。この膜はイオン交換容量が１. ５９ミリ当量／ｇ、８０℃での含水率が６８重量％、膜表面の水の接触角はクロルスルホン酸を含む反応混合液と接触していた側が３１°、クロルスルホン酸を含まない反応混合液と接触していた側が７１°であった。また、２５μm のγ線照射フィルムを同条件でグラフト反応し、クロルスルホン酸５容積部と１，２−ジクロロエタン６０容積部の混合液と両面を接触させそれ以降は前述と同じ工程で作製した膜のイオン交換容量は１. ７６ミリ当量／ｇ、８０℃での含水率は８１重量％であった。このことからできた固体高分子電解質膜の含水率は片面を大凡８８重量％で最高とし膜厚方向に連続的に減少していることがわかる。
【００３５】
実施例１と同じガス拡散電極で燃料電池を形成し、同条件でＶ−Ｉ特性を測定した。その結果、電流密度１Ａ／ｃｍ２で出力電圧は０. ４８Ｖであった。
【００３６】
（比較例）
フィルムの両面がスチレン１００容量部とキシレン３０容量部の混合液と接するようにしてグラフト反応を行ったこと以外は実施例１と同じ工程で固体高分子電解質膜を得た。できた膜のイオン交換容量は１. ７１ミリ当量／ｇ、８０℃での含水率は７３重量％、膜表面の水の接触角は２８°であった。
【００３７】
実施例１と同じガス拡散電極で燃料電池を形成し、同条件でＶ−Ｉ特性を測定した。その結果、電流密度１Ａ／ｃｍ２で出力電圧は０. ４２Ｖであった。
【００３８】
【発明の効果】
本発明は、以下の如く効果を有する。
【００３９】
即ち、本発明の固体高分子電解質型燃料電池は、正極と負極に適度の含水率と撥水性とを有し、固体高分子電解質型燃料電池として高電圧を出力し有用な性質を示す優れたものである。[0001]
[Industrial application fields]
The present invention relates to a method for producing a solid polymer electrolyte membrane used in a solid polymer electrolyte fuel cell .
[0002]
[Prior art]
Solid polymer electrolyte fuel cells are considered to be applied to automobiles and the like as small and light power sources using hydrogen and oxygen as fuel. Such a battery is composed of a solid polymer electrolyte membrane having ion exchange capacity, and a positive electrode and a negative electrode arranged in contact with both sides. Fuel hydrogen is oxidized electrochemically at the negative electrode, producing protons and electrons. This proton moves in the polymer electrolyte membrane to the positive electrode to which oxygen is supplied. On the other hand, electrons generated at the negative electrode pass through a load connected to the battery and flow to the positive electrode, where protons, oxygen, and electrons react to generate water.
[0003]
In this way, solid polymer electrolyte fuel cells are used as automotive power sources because of their low-temperature operability, small size, and high output density. A perfluorocarbon polymer film having a sulfonic acid group (trade name: Nafion, DuPont, trade name: Aciplex, Asahi Kasei Co., Ltd.) or the like is used as the electrolyte membrane. However, it cannot be said that the fuel cell output is still sufficient.
[0004]
Here, in order to improve the output of the battery, it is necessary to increase the hydrogen ion conductivity of the polymer electrolyte membrane and reduce the internal resistance of the membrane. This method includes increasing the concentration of ion exchange groups (for example, sulfonic acid groups) and decreasing the film thickness of the polymer electrolyte membrane. However, a significant increase in ion exchange groups increases the moisture content of the membrane more than necessary, and thus there are problems such as a decrease in output due to the electrode being too wet on the positive electrode side where water is generated in the fuel cell reaction.
[0005]
On the other hand, a decrease in film thickness has problems such as a decrease in battery output efficiency caused by a decrease in the mechanical strength of the film or an increase in the amount of hydrogen gas or oxygen gas that is a fuel permeated through the film.
[0006]
As a prior art document, there is JP-A-6-231781. Since this document has a low electric resistance, a cation exchange membrane comprising a laminate of perfluorocarbon polymer films having at least two or more sulfonic acid groups having different moisture contents is used as a solid electrolyte. Furthermore, the polymer electrolyte fuel cell has a structure in which polymer films having a high water content are sequentially laminated from the positive electrode side to the negative electrode side.
[0007]
As another prior art, Japanese Patent Application Laid-Open No. Hei 6-231782 has a low electrical resistance, so that the moisture content of the film facing the positive electrode is larger than that of the film facing the negative electrode. There is a polymer electrolyte fuel cell comprising a laminate of perfluorocarbon polymer films having at least two or more sulfonic acid groups having different moisture contents.
[0008]
[Problems to be solved by the invention]
However, in the former, the moisture content is greatly different before and after the lamination boundary, so that stress is generated near the boundary and mechanical durability is lowered. Moreover, since the reverse diffusion of water from the positive electrode, which occurs to compensate for the decrease in the water content of the negative electrode, cannot be efficiently performed due to the discontinuous change in the water content due to the lamination of the film, a large increase in output cannot be expected. The latter cannot be expected to increase the battery output due to the wetness of the positive electrode and the high resistance of the negative electrode.
[0009]
Here, in order to increase the output of the battery, it is necessary to increase the hydrogen ion conductivity of the polymer electrolyte membrane and reduce the internal resistance of the membrane. This greatly affects the amount of ion exchange groups (for example, sulfonic acid groups) in the membrane and the water content. The higher the ion exchange group content and the higher the water content, the higher the hydrogen ion conductivity.
[0010]
On the negative electrode side of the fuel cell, hydrogen ions made of hydrogen gas draw several water molecules and pass through the polymer electrolyte membrane to the positive electrode side, so that the side of the membrane in contact with the negative electrode has a relatively high moisture content. This will cause the output to drop. On the other hand, since water is generated by the fuel cell reaction on the side in contact with the positive electrode, water tends to exist excessively, and it is assumed that the water covers the catalyst and inhibits gas diffusion and causes a decrease in output.
[0011]
Therefore, the present invention provides that the moisture content is not uniform in the thickness direction but continuously changes in the thickness direction, the moisture content on the side in contact with the negative electrode is the highest, and that on the side in contact with the positive electrode is the lowest. By making the surface water-repellent, the reverse diffusion of water from the positive electrode that occurs to compensate for the decrease in the moisture content of the negative electrode occurs efficiently, and the positive electrode is prevented from becoming too wet, enabling efficient catalysis. It is intended to provide a solid polymer electrolyte fuel cell capable of achieving a high output.
[0021]
The technical means taken in claim 1 of the present invention (hereinafter referred to as first technical means) is as follows.
A method for producing a solid polymer electrolyte membrane having hydrogen ion conductivity for use in a solid polymer electrolyte fuel cell ,
In the step of changing the amount of ion exchange groups by bringing the precursor membrane of the solid polymer electrolyte membrane into contact with a reaction solution, the component that changes the amount of ion exchange groups only from one side of the precursor membrane is contacted It is a manufacturing method of the characteristic solid polymer electrolyte membrane.
The technical means taken in claim 2 of the present invention (hereinafter referred to as second technical means) is as follows.
A method for producing a solid polymer electrolyte membrane having hydrogen ion conductivity for use in a solid polymer electrolyte fuel cell ,
A step of changing the degree of cross-linking by bringing the precursor membrane of the solid polymer electrolyte membrane into contact with a reaction solution, and contacting the component that changes the degree of cross-linking only from one side of the precursor membrane This is a method for producing a polymer electrolyte membrane.
A solid polymer electrolyte fuel cell is formed by including a negative electrode in contact with one surface of the solid polymer electrolyte membrane and a positive electrode in contact with the other surface. The water content of the solid polymer electrolyte membrane is adjusted by the ion exchange capacity. Further, the water content of the solid polymer electrolyte membrane is adjusted by the degree of crosslinking. Using the solid polymer electrolyte membrane manufactured by the first technical means and the second technical means described above, the water content of the solid polymer electrolyte membrane is negative with respect to the thickness direction of the solid polymer electrolyte membrane. It is possible to manufacture a solid polymer electrolyte fuel cell that changes so as to continuously decrease from the side in contact with the positive electrode to the side in contact with the positive electrode.
It is desirable that the moisture content on the side in contact with the negative electrode of the solid polymer electrolyte membrane is at least 5% by weight or more than the moisture content on the side in contact with the positive electrode. When the water content is less than 5% by weight, the reverse diffusion of water from the positive electrode to the negative electrode is not efficiently performed.
It is desirable that the moisture content continuously changes in the range of 30 to 200% by weight with respect to the thickness direction of the solid polymer electrolyte membrane from the side in contact with the negative electrode of the solid polymer electrolyte membrane to the side in contact with the positive electrode. When the water content is less than 30% by weight, the internal resistance of the film increases, and when it exceeds 200% by weight, the film itself becomes hard and brittle in mechanical strength.
It is desirable that the solid polymer electrolyte membrane is made of a copolymer of a main chain formed of a copolymer of a fluorocarbon vinyl monomer and a hydrocarbon vinyl monomer and a hydrocarbon side chain having a sulfonic acid group. A solid polymer electrolyte membrane comprising a main chain formed of a copolymer of an olefin perfluorocarbon and an olefin hydrocarbon, and a side chain of a cross-linked copolymer of an olefin hydrocarbon having a sulfonic acid group and a diolefin hydrocarbon; More preferably, it is made of a copolymer of
[0022]
The continuously changing the water content of the high molecular electrolyte membrane in the thickness direction, obtained by continuously varying the ion exchange group content and degree of crosslinking in the film. The production method includes a main chain formed by a polymer electrolyte membrane of a copolymer of olefin perfluorocarbon and olefin hydrocarbon, and a cross-linked copolymer of olefin hydrocarbon having disulfonic acid group and diolefin hydrocarbon. In the case of a copolymer consisting of a side chain, the concentration of the sulfonic acid group attached to the side chain itself or the side chain is changed in the thickness direction of the film, or the degree of crosslinking by diolefin hydrocarbon is changed. Can be obtained.
[0023]
Specifically, when the side chain is introduced into the main chain copolymer film, the concentration or degree of crosslinking of the side chain itself or the degree of crosslinking by contacting the side chain synthesis raw material or the cross-linking forming raw material only from one side of the film, When the sulfone group is introduced, it can be produced by contacting the sulfonating agent only from one side of the film and continuously changing the concentration of the sulfonic acid group in the film thickness direction.
[0024]
In the present invention, the water content of the polymer film (acid type) is defined as follows.
[0025]
ΔW = (W 1 / W 2 −1) × 100 (% by weight)
W 1 : film weight after immersion for 3 hours in pure at 80 ° C.
[0026]
W 2 : Weight after vacuum drying at 100 ° C. for 24 hours after measuring W 1 .
[0027]
[Action]
As in the present invention, the moisture content is not uniform in the thickness direction but continuously changes in the thickness direction, and the moisture content on the side in contact with the negative electrode is the highest, and that on the side in contact with the positive electrode is the lowest. The water repellency effectively reverses the diffusion of water from the positive electrode to compensate for the decrease in the moisture content of the negative electrode, and prevents the positive electrode from becoming too wet, enabling efficient catalysis, resulting in fuel It is thought that the output of the battery can be increased.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the present invention will be described below.
[0029]
Example 1
After irradiating an ethylene-tetrafluoroethylene copolymer film (film thickness 50 μm) with a dose of 10 kGy in air at room temperature, one side of the film is a mixture of 100 parts by volume of styrene and 20 parts by volume of xylene. The other surface was brought into contact with xylene, and a graft reaction was performed at 60 ° C. for 2 hours. The both surfaces of the dried film were contacted with a mixed solution of 5 parts by volume of chlorosulfonic acid and 60 parts by volume of 1,2-dichloroethane at room temperature for 1 hour to carry out sulfonation reaction. After drying, it was hydrolyzed in 1N caustic potash and subsequently immersed in 1N hydrochloric acid. Next, it was washed with water at 90 ° C. for 1 hour. This solid polymer electrolyte membrane had an ion exchange capacity of 1.69 meq / g and a water content at 80 ° C. of 71% by weight. The contact angle of water on the membrane surface was 30 ° on the side in contact with styrene by the graft reaction and 72 ° on the xylene side (110 ° for the ethylene-tetrafluoroethylene copolymer film). A decrease in the contact angle of water indicates that many sulfonic acid groups have changed to hydrophilicity. In addition, a 25 μm γ-irradiated film was brought into contact with a mixed solution of 100 parts by volume of styrene and 20 parts by volume of xylene by a graft reaction, and thereafter the ion exchange capacity of the membrane prepared in the same process as described above was 1.80 meq / g The water content at 80 ° C. was 86% by weight. From this, it can be seen that the moisture content of the solid polymer electrolyte membrane made is highest at about 86% by weight on one side and continuously decreases in the film thickness direction.
[0030]
After applying Teflon dispersion to commercially available carbon paper, firing and water-repellent treatment are performed, and on this one side, a platinum-containing mixture of commercially available platinum-supported carbon (platinum weight 40%), commercially available Nafion solution and isopropanol is used as the platinum amount. A gas diffusion electrode was prepared by coating at 0.35 mg / cm 2.
[0031]
Using this gas diffusion electrode as a positive electrode and a negative electrode, a solid polymer electrolyte membrane was joined by hot pressing to form a fuel cell. The VI characteristics were measured at a hydrogen pressure of 2.5 atm (utilization rate of 80%), an air pressure of 2.5 atm (utilization rate of 40%), and a battery temperature of 80 ° C. As a result, the output voltage was 0.52 V at a current density of 1 A / cm2.
[0032]
(Example 2)
The other processing steps other than performing the grafting reaction with a mixed solution of 100 parts by volume of styrene and 30 parts by volume of xylene and a mixed solution of 95 parts by volume of styrene, 5 parts by volume of divinylbenzene, and 30 parts by volume of xylene are as in Example 1. Similarly, a solid polymer electrolyte membrane was obtained. This membrane had an ion exchange capacity of 1.63 meq / g and a moisture content at 80 ° C. of 69% by weight. The contact angle of water on the film surface was 52 ° on the side in contact with the reaction mixture containing divinylbenzene, and 33 ° on the side in contact with the reaction mixture containing no divinylbenzene. In addition, the ion exchange capacity and the water content at 80 ° C. of the electrolyte membrane prepared in the two types of reaction mixture in the graft reaction are 1.72 meq in the case of the membrane prepared in the reaction mixture containing divinylbenzene. The film prepared from the reaction mixture containing no divinylbenzene was 1.74 meq / g and 78% by weight. From this, it can be seen that the moisture content of the solid polymer electrolyte membrane continuously changed at about 61 to 78% by weight in the film thickness direction.
[0033]
A fuel cell was formed with the same gas diffusion electrode as in Example 1, and the VI characteristics were measured under the same conditions. As a result, the output voltage was 0.50 V at a current density of 1 A / cm2.
[0034]
(Example 3)
One side of the dried film was subjected to a graft reaction at 60 ° C. for 2 hours so that both surfaces of the film were in contact with a mixed solution of 100 parts by volume of styrene and 30 parts by volume of xylene. One side of the dried film was 5 parts by volume of chlorosulfonic acid and 1,2-dichloroethane 60. The sulfonation reaction was carried out at 40 ° C. for 1 hour with the volume of the mixture and the other surface in contact with 1,2-dichloroethane alone. Except for these two reactions, the same treatment steps as in Example 1 were performed to obtain a solid polymer electrolyte membrane. This membrane had an ion exchange capacity of 1.59 meq / g, a moisture content at 80 ° C. of 68% by weight, and the contact angle of water on the membrane surface was 31 ° on the side in contact with the reaction mixture containing chlorosulfonic acid. The side in contact with the reaction mixture containing no chlorosulfonic acid was 71 °. Also, a 25 μm γ-irradiated film is grafted under the same conditions, and a mixed solution of 5 parts by volume of chlorosulfonic acid and 60 parts by volume of 1,2-dichloroethane are brought into contact with each other. The ion exchange capacity was 1.76 meq / g, and the water content at 80 ° C. was 81% by weight. From this, it can be seen that the water content of the solid polymer electrolyte membrane is highest at about 88% by weight on one side and continuously decreases in the film thickness direction.
[0035]
A fuel cell was formed with the same gas diffusion electrode as in Example 1, and the VI characteristics were measured under the same conditions. As a result, the output voltage was 0.48 V at a current density of 1 A / cm2.
[0036]
(Comparative example)
A solid polymer electrolyte membrane was obtained in the same process as in Example 1 except that the graft reaction was performed so that both surfaces of the film were in contact with a mixed solution of 100 parts by volume of styrene and 30 parts by volume of xylene. The resulting membrane had an ion exchange capacity of 1.71 meq / g, a moisture content at 80 ° C. of 73% by weight, and a water contact angle of 28 ° on the membrane surface.
[0037]
A fuel cell was formed with the same gas diffusion electrode as in Example 1, and the VI characteristics were measured under the same conditions. As a result, the output voltage was 0.42 V at a current density of 1 A / cm2.
[0038]
【The invention's effect】
The present invention has the following effects.
[0039]
That is, the solid polymer electrolyte fuel cell of the present invention has an appropriate water content and water repellency at the positive electrode and the negative electrode, and is excellent as a solid polymer electrolyte fuel cell that outputs high voltage and exhibits useful properties. Is.
Claims (2)
前記固体高分子電解質膜の前駆体膜を反応液に接触させることによりイオン交換基量を変化させる工程で、前記前駆体膜の一方面からのみイオン交換基量を変化させる成分を接触させることを特徴とする固体高分子電解質膜の製造方法。 A method for producing a solid polymer electrolyte membrane having hydrogen ion conductivity for use in a solid polymer electrolyte fuel cell ,
In the step of changing the amount of ion exchange groups by bringing the precursor membrane of the solid polymer electrolyte membrane into contact with a reaction solution, the component that changes the amount of ion exchange groups only from one side of the precursor membrane is contacted A method for producing a solid polymer electrolyte membrane.
前記固体高分子電解質膜の前駆体膜を反応液に接触させることにより架橋度を変化させる工程で、前記前駆体膜の一方面からのみ架橋度を変化させる成分を接触させることを特徴とする固体高分子電解質膜の製造方法。 A method for producing a solid polymer electrolyte membrane having hydrogen ion conductivity for use in a solid polymer electrolyte fuel cell ,
A step of changing the degree of cross-linking by bringing the precursor membrane of the solid polymer electrolyte membrane into contact with a reaction solution, and contacting the component that changes the degree of cross-linking only from one side of the precursor membrane A method for producing a polymer electrolyte membrane.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32660197A JP4062755B2 (en) | 1997-11-27 | 1997-11-27 | Method for producing solid polymer electrolyte membrane |
| DE19854728A DE19854728B4 (en) | 1997-11-27 | 1998-11-26 | Polymer electrolyte fuel cell |
| US09/200,735 US6355370B2 (en) | 1997-11-27 | 1998-11-27 | Solid polyelectrolyte fuel cell having a solid polyelectrolyte membrane with varying water content |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32660197A JP4062755B2 (en) | 1997-11-27 | 1997-11-27 | Method for producing solid polymer electrolyte membrane |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11162485A JPH11162485A (en) | 1999-06-18 |
| JP4062755B2 true JP4062755B2 (en) | 2008-03-19 |
Family
ID=18189646
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32660197A Expired - Fee Related JP4062755B2 (en) | 1997-11-27 | 1997-11-27 | Method for producing solid polymer electrolyte membrane |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4062755B2 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4645794B2 (en) * | 2003-10-29 | 2011-03-09 | 信越化学工業株式会社 | Solid polymer electrolyte membrane and fuel cell |
| JP4586358B2 (en) * | 2003-12-11 | 2010-11-24 | 株式会社エクォス・リサーチ | Fuel cell system |
| JP5109311B2 (en) * | 2005-12-27 | 2012-12-26 | 日産自動車株式会社 | Membrane electrode assembly and fuel cell using the same |
| JP5059341B2 (en) | 2006-05-09 | 2012-10-24 | 株式会社トクヤマ | Diaphragm for direct liquid fuel cell |
| JP2008053101A (en) * | 2006-08-25 | 2008-03-06 | Toyota Motor Corp | Membrane-electrode assembly for fuel cell, and fuel cell |
| JP2008078127A (en) * | 2006-08-25 | 2008-04-03 | Sumitomo Chemical Co Ltd | Polymer electrolyte membrane, its laminate and their manufacturing method |
| US20090325028A1 (en) * | 2006-08-25 | 2009-12-31 | Sumitomo Chemical Company, Limited | Polymer electrolyte membrane, laminate thereof, and their production methods |
| JP2008053084A (en) * | 2006-08-25 | 2008-03-06 | Sumitomo Chemical Co Ltd | Fuel cell and membrane-electrode assembly therefor |
| JP2009070631A (en) | 2007-09-11 | 2009-04-02 | Fujifilm Corp | Electrolyte membrane, membrane electrode assembly, and fuel cell using membrane electrode assembly |
-
1997
- 1997-11-27 JP JP32660197A patent/JP4062755B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH11162485A (en) | 1999-06-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3417946B2 (en) | Electrochemical battery provided with polymer electrolyte and method for producing polymer electrolyte | |
| US6444343B1 (en) | Polymer electrolyte membranes for use in fuel cells | |
| US6242123B1 (en) | Solid polyelectrolyte membrane for fuel cells, and method for producing it | |
| US8283088B2 (en) | Silane crosslinked structure-introduced fuel-cell polymer electrolyte membrane and fuel-cell electrode assembly having the same | |
| JP5011567B2 (en) | Nano-inorganic particle composite cross-linked polymer electrolyte membrane, method for producing the same, and membrane / electrode assembly using the same | |
| JPH09102322A (en) | Solid polymeric electrolyte film for fuel cell and its manufacture | |
| US6355370B2 (en) | Solid polyelectrolyte fuel cell having a solid polyelectrolyte membrane with varying water content | |
| JP4532812B2 (en) | Fuel cell electrolyte membrane comprising a cross-linked fluoropolymer substrate | |
| JP2001229936A (en) | Electrolytic film and its production method | |
| US7629393B2 (en) | Solid polymer electrolyte membrane and process for producing the same, and fuel cell | |
| JP4625327B2 (en) | Fuel cell with polymer electrolyte membrane grafted by irradiation | |
| JP4062755B2 (en) | Method for producing solid polymer electrolyte membrane | |
| JPH0676838A (en) | Ion exchange membrane fuel cell and its manufacture | |
| JP5158353B2 (en) | Fuel cell electrolyte membrane and method for producing fuel cell electrolyte membrane / electrode assembly | |
| JPH11354140A (en) | Thin film electrolyte having high strength | |
| JP5326288B2 (en) | Solid polymer electrolyte membrane, method for producing the same, membrane electrode assembly for fuel cell, and fuel cell | |
| JPH11250921A (en) | Solid polymer electrolyte fuel cell | |
| JP2009151938A (en) | Solid polymer electrolyte membrane for fuel cell and fuel cell | |
| JP4692714B2 (en) | Method for producing solid polymer electrolyte membrane for fuel cell | |
| JP2002198067A (en) | High-temperature operating solid polymer composite electrolyte membrane, membrane/electrode bonded body and fuel cell | |
| JP2000090945A (en) | Solid polymer electrolyte film, manufacture thereof and solid polymer electrolyte fuel cell | |
| JP2003272663A (en) | Electrode structural body for fuel cell and solid polymer fuel cell using the same | |
| JP2004296278A (en) | Small fuel cell and electrolyte film | |
| JPH11176456A (en) | Solid high polymer electrolyte fuel cell | |
| JPWO2009034965A1 (en) | Solid polymer electrolyte membrane, method for producing solid polymer electrolyte membrane, and fuel cell |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20040902 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20051026 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20070320 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20070521 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20070724 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20070919 |
|
| A911 | Transfer of reconsideration by examiner before appeal (zenchi) |
Free format text: JAPANESE INTERMEDIATE CODE: A911 Effective date: 20071001 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20071023 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20071108 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20071211 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20071224 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110111 Year of fee payment: 3 |
|
| LAPS | Cancellation because of no payment of annual fees |