JPH10223234A - Manufacture of porous electrode substrate for phosphate-type fuel cell - Google Patents
Manufacture of porous electrode substrate for phosphate-type fuel cellInfo
- Publication number
- JPH10223234A JPH10223234A JP9035544A JP3554497A JPH10223234A JP H10223234 A JPH10223234 A JP H10223234A JP 9035544 A JP9035544 A JP 9035544A JP 3554497 A JP3554497 A JP 3554497A JP H10223234 A JPH10223234 A JP H10223234A
- Authority
- JP
- Japan
- Prior art keywords
- carbon
- carbon fiber
- porous electrode
- electrode substrate
- fuel cell
- 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.)
- Pending
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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Abstract
Description
【０００１】[0001]
【発明が属する技術分野】本発明は、リン酸型燃料電池
の主要部材であるサブストレートおよびリザーバー等に
使用される多孔質電極基板、とくに優れた耐蝕性により
長期に亘って高出力で安定操業できる炭素系のリン酸型
燃料電池用多孔質電極基板の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous electrode substrate used for a substrate and a reservoir which are main components of a phosphoric acid type fuel cell, and particularly to a stable operation with a high output for a long time due to excellent corrosion resistance. The present invention relates to a method for producing a carbon-based porous electrode substrate for a phosphoric acid type fuel cell.
【０００２】[0002]
【従来の技術】リン酸型燃料電池は、リン酸を保持した
電解質層の両側に白金触媒担持カーボンブラックを塗布
などにより電極触媒層を形成した多孔質電極基板を配置
して単位セルを構成し、各単位セルをセパレーター板を
介して所定のスタック構造に形成することにより組立て
られる。このうち、多孔質電極基板は電池性能の信頼性
に影響を与える重要な部材で、材質的に易ガス透過性、
耐熱性、耐蝕性、良導電性、良熱伝導性、易加工性など
の諸特性が要求される。2. Description of the Related Art A phosphoric acid type fuel cell comprises a unit cell in which a porous electrode substrate having an electrode catalyst layer formed by coating a platinum catalyst-supporting carbon black on both sides of an electrolyte layer holding phosphoric acid is arranged. Are assembled by forming each unit cell into a predetermined stack structure via a separator plate. Of these, the porous electrode substrate is an important member that affects the reliability of battery performance,
Various properties such as heat resistance, corrosion resistance, good electrical conductivity, good thermal conductivity, and easy workability are required.
【０００３】一般に、多孔質電極基板は炭素繊維のチョ
ップに熱硬化性樹脂を配合して板状に成形したのち焼成
炭化する方法、あるいは炭素繊維の前駆体シートに熱硬
化性樹脂を含浸したのち焼成炭化する方法により製造さ
れているが、後者の方法は繊維源として炭素化前のプレ
カーサーを用いる関係で焼成炭化処理が１回で済むうえ
シート形成が容易となる利点があるため、従来から数多
くの改良が試みられている。[0003] In general, a porous electrode substrate is formed by mixing a thermosetting resin into a chop of carbon fiber, forming it into a plate shape, and calcining and carbonizing, or impregnating a precursor sheet of carbon fiber with the thermosetting resin. Although it is manufactured by a method of calcining and carbonizing, the latter method has the advantage of requiring only one calcining and carbonizing treatment as well as facilitating sheet formation because a precursor before carbonization is used as a fiber source. Has been attempted.
【０００４】例えば強度や電気伝導性の向上を図る方法
として、ポリアクリロニトリル系繊維の織布または不織
布を張力下で不融化処理し、これに有機結合材を含浸し
たのち非酸化性雰囲気下で炭化する多孔質炭素板の製造
法（特開平２−51480 号公報）、特定量の人造有機繊
維、パルプおよび抄紙用バインダーを混合抄紙して得ら
れるシートに有機高分子溶液を含浸し、必要により不融
化処理を行ったのち、不活性雰囲気中で８００℃以上の
温度で加熱炭化する炭素繊維シートの製造法（特開平２
−58369 号公報) 、炭素化可能な有機高分子繊維を抄紙
後、熱硬化性樹脂を含浸し、積層圧着、炭素化して得ら
れる多孔質炭素の製造において、積層各含浸紙間に加熱
圧着時に炭素化可能で熱可塑的性質を有し、熱可塑性有
機高分子繊維を不融化する機能を有するフイルムを介在
させる多孔質炭素の製造法（特開平４−219370号公報)
等が提案されている。[0004] For example, as a method for improving strength and electrical conductivity, a woven or nonwoven fabric of polyacrylonitrile fiber is infusibilized under tension, impregnated with an organic binder, and then carbonized in a non-oxidizing atmosphere. A method for producing a porous carbon plate (Japanese Patent Application Laid-Open No. 2-51480), a sheet obtained by mixing a specific amount of artificial organic fibers, pulp, and a binder for papermaking is impregnated with an organic polymer solution. A method for producing a carbon fiber sheet in which a fusion treatment is performed and then carbonized by heating at a temperature of 800 ° C. or more in an inert atmosphere (Japanese Patent Laid-Open No.
No. -58369), papermaking organic carbon fibers capable of being carbonized, impregnating with a thermosetting resin, laminating and press-bonding, in the production of porous carbon obtained by carbonization, when heating and pressing between laminated impregnated papers. Method for producing porous carbon by interposing a film capable of being carbonized and having thermoplastic properties and having a function of infusing thermoplastic organic polymer fibers (Japanese Patent Laid-Open No. 4-219370)
Etc. have been proposed.
【０００５】また、この種の方法で形成される炭素繊維
シートに不足する耐薬品性の改善を図る目的で、未焼成
の炭素繊維製造用有機繊維あるいは該有機繊維を６５重
量％以上含む繊維集合体シートに、熱硬化性樹脂溶液を
含浸させたのち乾燥することによって、上記有機繊維の
表面をこの有機繊維に対して乾燥重量で５重量％以上の
量の熱硬化性樹脂で被覆する工程、上記熱硬化性樹脂を
熱硬化させて前駆体シートを作製する工程、前駆体シー
トを酸素ガス含有雰囲気中で１５０〜３５０℃の温度で
５時間以上安定化処理する工程、および安定化処理後の
前駆体シートを不活性ガス雰囲気中で１８００℃以上の
温度で焼成する工程を含む高黒鉛化多孔質炭素繊維シー
トの製造方法（特公平６−671 号公報、特公平７−3561
4 号公報）が提案されている。[0005] Further, in order to improve the chemical resistance of carbon fiber sheets formed by this type of method, unsintered organic fibers for producing carbon fibers or a fiber assembly containing the organic fibers in an amount of 65% by weight or more. A step of impregnating the body sheet with a thermosetting resin solution and then drying, thereby coating the surface of the organic fiber with a thermosetting resin in an amount of 5% by weight or more on a dry weight basis with respect to the organic fiber; A step of preparing a precursor sheet by thermally curing the thermosetting resin, a step of stabilizing the precursor sheet at a temperature of 150 to 350 ° C. for 5 hours or more in an atmosphere containing oxygen gas, and A method for producing a highly graphitized porous carbon fiber sheet including a step of firing a precursor sheet at a temperature of 1800 ° C. or more in an inert gas atmosphere (JP-B-6-671, JP-B-7-3561)
No. 4) has been proposed.
【０００６】上記した特公平６−６７１号公報や特公平
７−３５６１４号公報記載の発明は、炭素繊維の耐蝕性
が黒鉛化度に依存することに着目して開発されたもの
で、黒鉛化性の向上効果は有機繊維表面に被覆され、不
融化（安定化）に先立って硬化した熱硬化性樹脂が安定
化熱処理および焼成過程で炭素繊維の収縮を抑制し、炭
素繊維に緊張を与えたと同様の機能を果すためにもたら
されると推測している。しかしながら、有機繊維面に被
覆した熱硬化性樹脂膜は繊維の収縮に抗して緊張状態を
保つほどの収縮抑止力はないため、耐蝕性を大きく改善
するほどの黒鉛化性向上効果を期待することはできな
い。したがって、塩素に対して良好な耐蝕性が付与され
たとしても、リン酸中における電解酸化に対して充分な
安定性を確保することはできない。The inventions described in Japanese Patent Publication No. 6-671 and Japanese Patent Publication No. 7-35614 were developed by focusing on the fact that the corrosion resistance of carbon fibers depends on the degree of graphitization. The effect of improving the properties is that the thermosetting resin coated on the surface of the organic fiber and cured before infusibilization (stabilization) suppressed the shrinkage of the carbon fiber during the stabilization heat treatment and firing process, and gave tension to the carbon fiber. I speculate that it will be brought to perform a similar function. However, since the thermosetting resin film coated on the organic fiber surface does not have a shrinkage inhibiting force enough to maintain a tensioned state against the shrinkage of the fiber, it is expected to have a graphitizing property improving effect that greatly improves corrosion resistance. It is not possible. Therefore, even if good corrosion resistance is imparted to chlorine, sufficient stability to electrolytic oxidation in phosphoric acid cannot be ensured.
【０００７】一般に、黒鉛化度を上げることにより耐薬
品性や耐蝕性を向上させることができるが、単に黒鉛化
度を上げるのみでは、特にリン酸型燃料電池用多孔質電
極基板としてリン酸中の電解酸化に対して充分な耐蝕性
を付与するには限界がある。そこで、本出願人はリン酸
型燃料電池の多孔質電極基板を構成する炭素組織性状と
リン酸(200℃) 中における電解酸化に対する耐蝕性につ
いて研究を進め、多孔質電極基板の骨格表層部または／
および炭素繊維基材の表層面の黒鉛結晶配列がオニオン
スキン構造を有する場合に優れた耐蝕性が発揮される事
実を確認して、炭素繊維を含む多孔質炭素板の骨格表層
部にオニオンスキン構造の黒鉛表面層を形成する手段を
開発し、特願平７−２４３８３３号として提案した。In general, chemical resistance and corrosion resistance can be improved by increasing the degree of graphitization. However, simply increasing the degree of graphitization is particularly effective for phosphoric acid type fuel cell as a porous electrode substrate for phosphoric acid type fuel cells. There is a limit in providing sufficient corrosion resistance to electrolytic oxidation of aluminum. Therefore, the present applicant has been conducting research on the properties of the carbon structure constituting the porous electrode substrate of the phosphoric acid type fuel cell and the corrosion resistance to electrolytic oxidation in phosphoric acid (200 ° C), and has investigated the skeleton surface layer of the porous electrode substrate or /
And the fact that the graphite crystal arrangement on the surface layer of the carbon fiber base material has an onion skin structure exhibits excellent corrosion resistance, and the onion skin structure is formed on the skeleton surface layer of the porous carbon plate containing carbon fibers. A means for forming a graphite surface layer was developed and proposed as Japanese Patent Application No. 7-243833.
【０００８】[0008]
【発明が解決しようとする課題】本発明者は、上記の特
願平７−２４３８３３号の技術を発展させて、炭素繊維
で構成した多孔質炭素基材の表層部に形成した黒鉛表面
層をフッ素化処理により改質してリン酸に対する濡れ性
を低下させることにより、耐蝕性が著しく向上できるこ
とを見出した。SUMMARY OF THE INVENTION The present inventor has developed the technique of Japanese Patent Application No. 7-243833, and developed a graphite surface layer formed on a surface layer of a porous carbon substrate made of carbon fibers. It has been found that the corrosion resistance can be remarkably improved by reducing the wettability to phosphoric acid by modifying by fluorination treatment.
【０００９】本発明は、この知見に基づいて開発された
もので、その目的は高出力で長期に亘って、安定に発電
操業することのできるリン酸型燃料電池用多孔質電極基
板の製造方法を提供することにある。The present invention has been developed based on this finding, and its object is to provide a method for producing a porous electrode substrate for a phosphoric acid type fuel cell capable of stably generating power for a long time with a high output. Is to provide.
【００１０】[0010]
【課題を解決するための手段】上記の目的を達成するた
めの本発明によるリン酸型燃料電池用多孔質電極基板の
製造方法は、残炭率４０％以上の有機高分子物質を有機
溶媒に溶解した溶液を炭素繊維基材に含浸し、乾燥、加
熱硬化して有機高分子物質を炭素繊維基材に被着し、不
活性雰囲気中８００℃以上の温度により焼成炭化した
後、２３００℃以上の温度で熱処理して炭素繊維基材表
層部に黒鉛質被膜を形成し、次いでフッ素化処理を施す
ことを構成上の特徴とする。According to the present invention, there is provided a method for producing a porous electrode substrate for a phosphoric acid type fuel cell, comprising the steps of: converting an organic polymer having a residual carbon ratio of 40% or more into an organic solvent; The dissolved solution is impregnated into the carbon fiber base material, dried, heat-cured, and the organic polymer substance is applied to the carbon fiber base material, and calcined and carbonized at a temperature of 800 ° C. or more in an inert atmosphere. The composition is characterized in that a graphite coating is formed on the surface layer of the carbon fiber base material by heat treatment at a temperature of, and then a fluorination treatment is performed.
【００１１】[0011]
【発明の実施の形態】リン酸型燃料電池用多孔質電極基
板を構成する炭素繊維の種類には特に限定はなく、ポリ
アクリロニトリル系炭素繊維、レーヨン系炭素繊維、ピ
ッチ系炭素繊維などいずれも用いることができ、チョッ
プドした短繊維状の炭素繊維が使用される。これらの短
繊維状炭素繊維は、パルプ等の賦形剤とともに水中に分
散させて、分散液を抄紙法によりシート化する公知の方
法により炭素繊維基材が作製される。BEST MODE FOR CARRYING OUT THE INVENTION The type of carbon fibers constituting a porous electrode substrate for a phosphoric acid type fuel cell is not particularly limited, and any of polyacrylonitrile-based carbon fibers, rayon-based carbon fibers, pitch-based carbon fibers, etc. may be used. Chopped short fiber carbon fibers can be used. These short fibrous carbon fibers are dispersed in water together with an excipient such as pulp, and a carbon fiber base material is prepared by a known method in which the dispersion is formed into a sheet by a papermaking method.
【００１２】有機高分子物質を炭素繊維基材に被着する
ために、残炭率が４０％以上の有機高分子物質を有機溶
媒に溶解した溶液が用いられる。残炭率が４０％以上と
は、有機高分子物質を非酸化性雰囲気下で８００℃の温
度により焼成炭化処理した際に、固形分の４０重量％以
上が炭素として残留することを指す。このような残炭率
４０％以上の有機高分子物質としては、フェノール系樹
脂、フラン系樹脂、ポリイミド樹脂、ポリカルボジイミ
ド樹脂、石油系もしくは石炭系のピッチ等を挙げること
ができる。また、有機溶媒としては、メタノール、エタ
ノール、ベンゼン、アセトン、トルエン、キノリン、テ
トラヒドロフラン等が適用される。有機高分子物質を有
機溶媒に適宜な濃度に溶解した溶液を、上記の炭素繊維
基材に浸漬や塗布等の方法により含浸したのち風乾して
有機溶媒を除去し、更に１００〜２５０℃に加熱して有
機高分子物質を硬化処理することにより、有機高分子物
質が炭素繊維基材に被着される。In order to apply the organic polymer substance to the carbon fiber substrate, a solution in which an organic polymer substance having a residual carbon ratio of 40% or more dissolved in an organic solvent is used. A residual carbon ratio of 40% or more means that when the organic polymer substance is calcined and carbonized at a temperature of 800 ° C. in a non-oxidizing atmosphere, 40% by weight or more of the solid content remains as carbon. Examples of such an organic polymer substance having a residual carbon ratio of 40% or more include a phenol resin, a furan resin, a polyimide resin, a polycarbodiimide resin, and a petroleum or coal pitch. As the organic solvent, methanol, ethanol, benzene, acetone, toluene, quinoline, tetrahydrofuran, or the like is applied. A solution obtained by dissolving an organic polymer substance at an appropriate concentration in an organic solvent is impregnated into the carbon fiber substrate by a method such as dipping or coating, and then air-dried to remove the organic solvent, and further heated to 100 to 250 ° C. Then, the organic polymer substance is subjected to a curing treatment, whereby the organic polymer substance is adhered to the carbon fiber base material.
【００１３】炭素繊維基材に被着した有機高分子物質
は、不活性雰囲気中で８００℃以上の温度に、好ましく
は８００〜１２００℃の温度に加熱して焼成炭化され
る。次いで、不活性雰囲気中２３００℃以上の温度によ
り熱処理することにより黒鉛化して炭素繊維基材の表層
部に黒鉛質被膜が形成される。熱処理温度が２３００℃
未満では黒鉛化が充分に進まず２３００℃以上の温度で
熱処理することが必要であるが、３０００℃以上の温度
での熱処理は不要でありエネルギー経済性の面から熱処
理温度は３０００℃以下が望ましい。The organic polymer substance applied to the carbon fiber base material is calcined by heating to a temperature of 800 ° C. or more, preferably 800 to 1200 ° C. in an inert atmosphere. Next, it is graphitized by heat treatment at a temperature of 2300 ° C. or more in an inert atmosphere to form a graphitic film on the surface layer of the carbon fiber base material. Heat treatment temperature is 2300 ℃
If it is less than 1, it is necessary to heat-treat at a temperature of 2300 ° C. or higher without sufficiently progressing graphitization. However, a heat treatment at a temperature of 3000 ° C. or higher is unnecessary, and the heat-treatment temperature is preferably 3000 ° C. or lower from the viewpoint of energy economy. .
【００１４】このようにして、表層部に黒鉛質被膜を形
成した炭素繊維基材をフッ素化処理して表面を改質する
ことが、本発明の主要な構成要素である。フッ素化処理
は、黒鉛質被膜および炭素繊維基材部のＣ−Ｃ結合を、
Ｃ−Ｆ結合に転換することによりリン酸に対する濡れ性
の低下を図るものであり、フッ素化処理はフッ素含有ガ
ス中で加熱処理することにより行うことができる。フッ
素含有ガスとしてはフッ素ガスをはじめ揮発性のＡｇ
Ｆ、ＩＦ5 、ＭｏＦ6 、ＣＦ4 、ＳＦ4 等を用いること
ができる。また、フッ素イオンを含む電解質水溶液中に
おいて電解処理することによりフッ素化処理することも
可能である。The main component of the present invention is to modify the surface of the carbon fiber substrate having the graphite layer formed on the surface layer by fluorination treatment. In the fluorination treatment, the C-C bond between the graphite coating and the carbon fiber base is
The conversion into C—F bonds reduces the wettability to phosphoric acid, and the fluorination treatment can be performed by heat treatment in a fluorine-containing gas. Volatile Ag including fluorine gas as fluorine-containing gas
F, IF 5 , MoF 6 , CF 4 , SF 4 and the like can be used. Further, the fluorination treatment can be performed by performing an electrolytic treatment in an aqueous electrolyte solution containing fluorine ions.
【００１５】しかしながら、好ましいフッ素化処理の方
法は、フッ素含有ガスをプラズマ反応により原子状のフ
ッ素イオンと炭素繊維基材表層部の黒鉛質被膜とを反応
させてＣ−Ｆ結合に転換する方法である。プラズマ反応
によりフッ素化処理する場合に、反応条件が強力である
とエッチングにより表面粗化が生じて耐蝕性が低下した
り電気伝導性が低下する場合があるので、プラズマ反応
を適度なレベルに設定することが望ましい。具体的に
は、黒鉛質被膜を形成した炭素繊維基材をプラズマリア
クター内に配置して、ＣＦ4 ガスを流入しながら、マイ
クロ波出力を３０Ｗ以下の条件で、反応時間を１０分以
下に設定することが好ましい条件設定となる。However, a preferred fluorination method is a method in which a fluorine-containing gas is converted into C—F bonds by reacting atomic fluorine ions with a graphitic film on the surface of a carbon fiber base material by a plasma reaction. is there. In the case of fluorination treatment by plasma reaction, if the reaction conditions are strong, surface roughening will occur due to etching, which may reduce corrosion resistance or electrical conductivity, so set the plasma reaction to an appropriate level It is desirable to do. Specifically, the carbon fiber substrate on which the graphite coating was formed was placed in a plasma reactor, and the reaction time was set to 10 minutes or less under the condition of a microwave output of 30 W or less while flowing CF 4 gas. This is a preferable condition setting.
【００１６】本発明のリン酸型燃料電池用多孔質電極基
板の製造方法は黒鉛質被膜の形成過程において、炭素繊
維基材に被着した有機高分子物質層は収縮しながら炭素
化するが、炭素繊維基材は収縮現象を生じないから、有
機高分子物質は実質的に緊張状態下で炭素化、黒鉛化が
進行する。この作用で、炭素六角網面が基材炭素面と平
行に配列したオニオンスキン構造の結晶性状を有し、高
度に黒鉛化した黒鉛質被膜が形成される。更に、フッ素
化処理を施すことにより黒鉛質被膜や炭素繊維基材表層
部にＣ−Ｆの共有結合が形成され、リン酸に対する濡れ
性が低下するのでリン酸による腐食が著しく低減し、耐
蝕性の向上を図ることができる。したがって、長時間に
亘り安定に高出力の発電操業することが可能となる。According to the method for producing a porous electrode substrate for a phosphoric acid fuel cell of the present invention, the organic polymer material layer adhered to the carbon fiber substrate is carbonized while shrinking during the formation of the graphite coating. Since the carbon fiber base material does not cause a shrinkage phenomenon, carbonization and graphitization of the organic polymer substance proceed under substantially tension. By this action, a highly graphitic graphitic film having an onion skin structure in which the hexagonal carbon plane is arranged in parallel with the carbon plane of the base material and having a high degree of graphitization is formed. Further, by performing the fluorination treatment, a covalent bond of CF is formed in the graphite coating or the surface layer of the carbon fiber base material, and the wettability to phosphoric acid is reduced, so that the corrosion due to phosphoric acid is significantly reduced, and the corrosion resistance is reduced. Can be improved. Therefore, it is possible to stably perform a high-output power generation operation for a long time.
【００１７】[0017]
【実施例】以下、本発明の実施例を比較例と対比しなが
ら具体的に説明する。なお、本発明の範囲はこれらの実
施例に限られるものではない。EXAMPLES Examples of the present invention will be specifically described below in comparison with comparative examples. The scope of the present invention is not limited to these examples.
【００１８】実施例１〜８、比較例１〜４ 長さ６mmにチョップされたポリアクリロニトリル系炭素
繊維〔東レ（株）製、T300〕８０重量部を針葉樹パルプ
２０重量部とともに水中に入れて撹拌し、均一な分散液
を調製した。この分散液を抄紙し、乾燥してシート状の
炭素繊維成形体からなる炭素繊維基材を作製した。有機
高分子物質としてフェノール樹脂〔住友デュレズ（株）
製、PR940 〕を用い、３０％の濃度でアセトンに溶解し
た溶液中に炭素繊維基材を浸漬し、風乾してアセトンを
除去したのち厚さが２mmとなるように積層し、温度１５
０℃、圧力１０kg/cm2の熱圧条件で成形硬化した。この
ようにして、炭素繊維基材にフェノール樹脂を被着し、
その両面を黒鉛板に挟み付けた状態で窒素雰囲気に保持
された焼成炉に入れて１０００℃の温度で焼成炭化した
後、アルゴン雰囲気に保持された黒鉛化炉中で異なる温
度により熱処理して炭素繊維基材の表層部に黒鉛質の被
膜を形成した。Examples 1 to 8, Comparative Examples 1 to 4 80 parts by weight of polyacrylonitrile-based carbon fiber chopped to a length of 6 mm (T300, manufactured by Toray Industries, Inc.) are put into water together with 20 parts by weight of softwood pulp and stirred. Then, a uniform dispersion was prepared. This dispersion was paper-made and dried to prepare a carbon fiber substrate made of a sheet-like carbon fiber molded body. Phenolic resin [Sumitomo Durez Co., Ltd.]
PR940], a carbon fiber substrate was immersed in a solution of acetone at a concentration of 30%, air-dried to remove acetone, and laminated to a thickness of 2 mm.
Molding and curing were performed at 0 ° C. under a pressure of 10 kg / cm 2 . In this way, the phenolic resin is applied to the carbon fiber base material,
In a state where the both surfaces are sandwiched between graphite plates, the mixture is placed in a baking furnace maintained in a nitrogen atmosphere and calcined at a temperature of 1000 ° C., and then heat-treated at different temperatures in a graphitization furnace maintained in an argon atmosphere. A graphite coating was formed on the surface layer of the fiber base material.
【００１９】この黒鉛質被膜を形成した炭素繊維基材を
プラズマリアクター〔ヤマト科学（株）製、PR41〕に入
れて、ＣＦ4 ガスを３５ml／分の割合で供給しながら、
マイクロ波出力および反応時間を変えてフッ素化処理を
行った。The carbon fiber substrate on which the graphite coating was formed was put into a plasma reactor (PR41, manufactured by Yamato Kagaku Co., Ltd.), and CF 4 gas was supplied at a rate of 35 ml / min.
The fluorination treatment was performed while changing the microwave output and the reaction time.
【００２０】このようにして製造した多孔質電極基板を
２３０℃の熱リン酸中に浸漬して、１．２ V／RHE の一
定電位における１０００分後の腐食電流の測定および腐
食による重量減少率を測定して耐蝕性を評価した。な
お、リン酸は市販品を１９５℃で１６時間加熱脱水して
１００％リン酸液に調整して使用した。また、定電位腐
食試験前に試験片上にマイクロシリンジで１００％リン
酸を０．１ml滴下してその拡大写真から接触角を測定し
てリン酸との濡れ性を評価した。The porous electrode substrate thus manufactured was immersed in hot phosphoric acid at 230 ° C., and the corrosion current was measured after 1000 minutes at a constant potential of 1.2 V / RHE. Was measured to evaluate the corrosion resistance. The phosphoric acid was prepared by heating and dehydrating a commercially available product at 195 ° C. for 16 hours to prepare a 100% phosphoric acid solution. Further, before the constant potential corrosion test, 0.1 ml of 100% phosphoric acid was dropped on the test piece with a microsyringe, and the contact angle was measured from the enlarged photograph to evaluate the wettability with phosphoric acid.
【００２１】このようにして得られた各電極基板の性能
評価の結果を、製造条件と対比して表１に示した。The results of the performance evaluation of each of the electrode substrates thus obtained are shown in Table 1 in comparison with the manufacturing conditions.
【００２２】[0022]
【表１】 [Table 1]
【００２３】表１の結果から、本発明の要件を満たす実
施例の多孔質電極基板はいずれも腐食電流値が小さく、
腐食による重量減少も少ないことが判る。また、接触角
が増大しており、リン酸に対する濡れ性が低下すること
が認められる。なお、フッ素化処理条件としてマイクロ
波出力を大きくした実施例４、５、６や反応時間を長く
した実施例７、８では耐蝕性が若干劣る傾向にある。こ
れに対し、黒鉛質被膜の形成温度が低い比較例１、２で
は黒鉛化が充分でないために腐食電流値が大きく、腐食
による重量減少も多くなり、更にフッ素化処理を施さな
い比較例３、４では接触角の増加が認められずリン酸に
対する濡れ性の低下が充分でないことが判明する。From the results shown in Table 1, all of the porous electrode substrates of the examples satisfying the requirements of the present invention have small corrosion current values,
It can be seen that the weight loss due to corrosion is small. Further, it is recognized that the contact angle is increased and the wettability to phosphoric acid is reduced. In Examples 4, 5, and 6 in which the microwave output was increased as the fluorination treatment conditions and Examples 7 and 8 in which the reaction time was increased, the corrosion resistance tended to be slightly inferior. On the other hand, in Comparative Examples 1 and 2 in which the formation temperature of the graphitic film was low, the graphitization was not sufficient, so that the corrosion current value was large, the weight loss due to corrosion was large, and Comparative Examples 3 and 4 in which no fluorination treatment was performed. In No. 4, no increase in the contact angle was observed, indicating that the wettability to phosphoric acid was not sufficiently reduced.
【００２４】[0024]
【発明の効果】以上のとおり、本発明のリン酸型燃料電
池用多孔質電極基板の製造方法によれば、炭素繊維基材
表層部に黒鉛質被膜を形成して、更にフッ素化処理を施
すことにより、リン酸に対する濡れ性が低下して熱リン
酸中での電解酸化に対する耐蝕性を著しく向上すること
が可能となる。したがって、高出力の発電時にも安定に
長時間の発電操業をすることができ、リン酸型燃料電池
用の多孔質電極基板の製造技術として極めて有用であ
る。As described above, according to the method for producing a porous electrode substrate for a phosphoric acid type fuel cell of the present invention, a graphite coating is formed on the surface layer of a carbon fiber base material, and further subjected to a fluorination treatment. Thereby, the wettability to phosphoric acid is reduced, and the corrosion resistance to electrolytic oxidation in hot phosphoric acid can be significantly improved. Therefore, the power generation operation can be stably performed for a long time even at the time of high-output power generation, which is extremely useful as a technology for manufacturing a porous electrode substrate for a phosphoric acid fuel cell.
Claims (3)
機溶媒に溶解した溶液を炭素繊維基材に含浸し、乾燥、
加熱硬化して有機高分子物質を炭素繊維基材に被着し、
不活性雰囲気中８００℃以上の温度により焼成炭化した
後、２３００℃以上の温度で熱処理して炭素繊維基材表
層部に黒鉛質被膜を形成し、次いでフッ素化処理を施す
ことを特徴とするリン酸型燃料電池用多孔質電極基板の
製造方法。1. A carbon fiber base material is impregnated with a solution in which an organic polymer substance having a residual carbon ratio of 40% or more is dissolved in an organic solvent, and dried.
Heat-cured to apply the organic polymer substance to the carbon fiber base material,
After firing and carbonizing at a temperature of 800 ° C. or more in an inert atmosphere, a heat treatment is performed at a temperature of 2300 ° C. or more to form a graphitic film on the surface layer of the carbon fiber base material, and then a fluorination treatment is performed. A method for producing a porous electrode substrate for an acid fuel cell.
とによりフッ素化処理を施す、請求項１記載のリン酸型
燃料電池用多孔質電極基板の製造方法。2. The method for producing a porous electrode substrate for a phosphoric acid type fuel cell according to claim 1, wherein the fluorination treatment is performed by causing a plasma reaction of a fluorine-containing gas.
ラズマリアクター内に配置して、ＣＦ4 ガスを流入しな
がら、マイクロ波出力３０Ｗ以下、反応時間１０分以下
のプラズマ反応条件でフッ素化処理を施す、請求項１又
は２記載のリン酸型燃料電池用多孔質電極基板の製造方
法。3. A carbon fiber substrate on which a graphitic film is formed is placed in a plasma reactor and fluorinated under a plasma reaction condition of a microwave output of 30 W or less and a reaction time of 10 minutes or less while flowing CF 4 gas. The method for producing a porous electrode substrate for a phosphoric acid type fuel cell according to claim 1, wherein the treatment is performed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9035544A JPH10223234A (en) | 1997-02-04 | 1997-02-04 | Manufacture of porous electrode substrate for phosphate-type fuel cell |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9035544A JPH10223234A (en) | 1997-02-04 | 1997-02-04 | Manufacture of porous electrode substrate for phosphate-type fuel cell |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH10223234A true JPH10223234A (en) | 1998-08-21 |
Family
ID=12444681
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9035544A Pending JPH10223234A (en) | 1997-02-04 | 1997-02-04 | Manufacture of porous electrode substrate for phosphate-type fuel cell |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH10223234A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20170107790A (en) * | 2016-03-16 | 2017-09-26 | 주식회사 엘지화학 | Redox flow battery |
-
1997
- 1997-02-04 JP JP9035544A patent/JPH10223234A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20170107790A (en) * | 2016-03-16 | 2017-09-26 | 주식회사 엘지화학 | Redox flow battery |
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