JP4833087B2 - ELECTROLYTE MEMBRANE REINFORCEMENT, ELECTROLYTE MEMBRANE AND FUEL CELL USING SAME, AND METHOD FOR PRODUCING ELECTROLYTE MEMBRANE REINFORCEMENT - Google Patents
ELECTROLYTE MEMBRANE REINFORCEMENT, ELECTROLYTE MEMBRANE AND FUEL CELL USING SAME, AND METHOD FOR PRODUCING ELECTROLYTE MEMBRANE REINFORCEMENT Download PDFInfo
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- JP4833087B2 JP4833087B2 JP2006552933A JP2006552933A JP4833087B2 JP 4833087 B2 JP4833087 B2 JP 4833087B2 JP 2006552933 A JP2006552933 A JP 2006552933A JP 2006552933 A JP2006552933 A JP 2006552933A JP 4833087 B2 JP4833087 B2 JP 4833087B2
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- Prior art keywords
- electrolyte membrane
- reinforcing material
- glass fiber
- phosphosilicate
- electrolyte
- Prior art date
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- 239000003792 electrolyte Substances 0.000 title claims description 86
- 239000012528 membrane Substances 0.000 title claims description 84
- 239000000446 fuel Substances 0.000 title claims description 16
- 238000004519 manufacturing process Methods 0.000 title claims description 12
- 230000002787 reinforcement Effects 0.000 title claims description 7
- 239000003365 glass fiber Substances 0.000 claims description 109
- 239000012779 reinforcing material Substances 0.000 claims description 77
- 150000001875 compounds Chemical class 0.000 claims description 37
- 239000011248 coating agent Substances 0.000 claims description 33
- 238000000576 coating method Methods 0.000 claims description 33
- 108010025899 gelatin film Proteins 0.000 claims description 17
- 125000005843 halogen group Chemical group 0.000 claims description 15
- -1 γ-glycidoxypropyl group Chemical group 0.000 claims description 15
- 239000005518 polymer electrolyte Substances 0.000 claims description 14
- 125000000217 alkyl group Chemical group 0.000 claims description 13
- 239000007858 starting material Substances 0.000 claims description 11
- 125000000962 organic group Chemical group 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 7
- 125000002467 phosphate group Chemical group [H]OP(=O)(O[H])O[*] 0.000 claims description 6
- 239000006087 Silane Coupling Agent Substances 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 5
- 125000003545 alkoxy group Chemical group 0.000 claims description 3
- 239000004745 nonwoven fabric Substances 0.000 description 36
- 239000000203 mixture Substances 0.000 description 26
- 238000000034 method Methods 0.000 description 21
- 239000011521 glass Substances 0.000 description 20
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical group OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 19
- 239000006185 dispersion Substances 0.000 description 15
- 239000000835 fiber Substances 0.000 description 11
- 238000001035 drying Methods 0.000 description 9
- 235000011007 phosphoric acid Nutrition 0.000 description 9
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- 238000009833 condensation Methods 0.000 description 7
- 230000005494 condensation Effects 0.000 description 7
- 239000000243 solution Substances 0.000 description 7
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 5
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 5
- 229910052731 fluorine Inorganic materials 0.000 description 5
- 239000011737 fluorine Substances 0.000 description 5
- 125000001424 substituent group Chemical group 0.000 description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 230000007062 hydrolysis Effects 0.000 description 4
- 238000006460 hydrolysis reaction Methods 0.000 description 4
- 230000003301 hydrolyzing effect Effects 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 150000004703 alkoxides Chemical class 0.000 description 3
- 239000008151 electrolyte solution Substances 0.000 description 3
- 229920002313 fluoropolymer Polymers 0.000 description 3
- 238000007731 hot pressing Methods 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- 229920000098 polyolefin Polymers 0.000 description 3
- 229920000557 Nafion® Polymers 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 125000002843 carboxylic acid group Chemical group 0.000 description 2
- 238000007865 diluting Methods 0.000 description 2
- XPPKVPWEQAFLFU-UHFFFAOYSA-N diphosphoric acid Chemical compound OP(O)(=O)OP(O)(O)=O XPPKVPWEQAFLFU-UHFFFAOYSA-N 0.000 description 2
- 239000004811 fluoropolymer Substances 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 238000005342 ion exchange Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 229910000077 silane Inorganic materials 0.000 description 2
- 239000008279 sol Substances 0.000 description 2
- 238000003980 solgel method Methods 0.000 description 2
- 125000000542 sulfonic acid group Chemical group 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- RRZIJNVZMJUGTK-UHFFFAOYSA-N 1,1,2-trifluoro-2-(1,2,2-trifluoroethenoxy)ethene Chemical group FC(F)=C(F)OC(F)=C(F)F RRZIJNVZMJUGTK-UHFFFAOYSA-N 0.000 description 1
- ZPQAUEDTKNBRNG-UHFFFAOYSA-N 2-methylprop-2-enoylsilicon Chemical compound CC(=C)C([Si])=O ZPQAUEDTKNBRNG-UHFFFAOYSA-N 0.000 description 1
- 229920003934 Aciplex® Polymers 0.000 description 1
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 229920003935 Flemion® Polymers 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- UEZVMMHDMIWARA-UHFFFAOYSA-N Metaphosphoric acid Chemical compound OP(=O)=O UEZVMMHDMIWARA-UHFFFAOYSA-N 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- NOKSMMGULAYSTD-UHFFFAOYSA-N [SiH4].N=C=O Chemical compound [SiH4].N=C=O NOKSMMGULAYSTD-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000003377 acid catalyst Substances 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 125000003277 amino group Chemical group 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 description 1
- 229910052794 bromium Inorganic materials 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 235000011180 diphosphates Nutrition 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 125000003700 epoxy group Chemical group 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- XPBBUZJBQWWFFJ-UHFFFAOYSA-N fluorosilane Chemical compound [SiH3]F XPBBUZJBQWWFFJ-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 229940085991 phosphate ion Drugs 0.000 description 1
- 239000005360 phosphosilicate glass Substances 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 229920005597 polymer membrane Polymers 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- FZHAPNGMFPVSLP-UHFFFAOYSA-N silanamine Chemical compound [SiH3]N FZHAPNGMFPVSLP-UHFFFAOYSA-N 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000007784 solid electrolyte Substances 0.000 description 1
- TXDNPSYEJHXKMK-UHFFFAOYSA-N sulfanylsilane Chemical compound S[SiH3] TXDNPSYEJHXKMK-UHFFFAOYSA-N 0.000 description 1
- UQMOLLPKNHFRAC-UHFFFAOYSA-N tetrabutyl silicate Chemical compound CCCCO[Si](OCCCC)(OCCCC)OCCCC UQMOLLPKNHFRAC-UHFFFAOYSA-N 0.000 description 1
- LFQCEHFDDXELDD-UHFFFAOYSA-N tetramethyl orthosilicate Chemical compound CO[Si](OC)(OC)OC LFQCEHFDDXELDD-UHFFFAOYSA-N 0.000 description 1
- ZQZCOBSUOFHDEE-UHFFFAOYSA-N tetrapropyl silicate Chemical compound CCCO[Si](OCCC)(OCCC)OCCC ZQZCOBSUOFHDEE-UHFFFAOYSA-N 0.000 description 1
- BPSIOYPQMFLKFR-UHFFFAOYSA-N trimethoxy-[3-(oxiran-2-ylmethoxy)propyl]silane Chemical compound CO[Si](OC)(OC)CCCOCC1CO1 BPSIOYPQMFLKFR-UHFFFAOYSA-N 0.000 description 1
- UKRDPEFKFJNXQM-UHFFFAOYSA-N vinylsilane Chemical compound [SiH3]C=C UKRDPEFKFJNXQM-UHFFFAOYSA-N 0.000 description 1
- 239000002759 woven fabric Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M8/1016—Fuel cells with solid electrolytes characterised by the electrolyte material
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
- C03C25/10—Coating
- C03C25/42—Coatings containing inorganic materials
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
- H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
- H01B1/12—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances organic substances
- H01B1/122—Ionic conductors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0289—Means for holding the electrolyte
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2300/00—Electrolytes
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0065—Solid electrolytes
- H01M2300/0068—Solid electrolytes inorganic
-
- 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
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Electrochemistry (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Inorganic Chemistry (AREA)
- Geochemistry & Mineralogy (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Fuel Cell (AREA)
- Reinforced Plastic Materials (AREA)
- Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
- Conductive Materials (AREA)
Description
【技術分野】
【０００１】
本発明は、電解質膜補強材およびそれを用いた電解質膜と燃料電池、ならびに電解質膜補強材の製造方法に関する。
【背景技術】
【０００２】
燃料電池は、発電効率が高く、環境負荷が小さいという特徴を有する。燃料電池の中でも、高分子電解質型燃料電池（ＰＥＦＣ）は、高出力で小型軽量化が容易であり、さらに量産効果による低コスト化も可能である。そのため、ＰＥＦＣは、小規模オンサイト型、自動車用、携帯用の燃料電池として期待されている。
【０００３】
現在、高分子プロトン伝導性膜（高分子電解質膜）として主に使用されているものは、パーフルオロアルキレン鎖を主骨格とし、スルホン酸基やカルボン酸基等のイオン交換基を含有するフッ素系高分子の膜である。しかし、これらのフッ素系高分子膜は含水にともなって膨潤し、寸法の増大、機械強度の低下、長時間運転時のクリープ発生を招く。したがって、フッ素系高分子膜単独では、セル形成時の取扱い性および運転開始後の耐久性が低いという問題がある。
【０００４】
このような問題を解決するために、各種補強材による高分子膜の補強が試みられており、たとえばガラス繊維を用いた電解質膜が提案されている（たとえば、特開平１０−３１２８１５号公報、特開２００４−０４７４５０号公報、特開２００４−３１９４２１号公報）。
【０００５】
しかしながら、ガラス繊維自体はプロトン伝導性を有さないため、補強材の量が多くなるほど電解質膜のプロトン伝導性が低下するという問題があった。そのため、プロトン伝導性を維持しながら、高い強度の補強材を得ることは難しかった。
【発明の開示】
【０００６】
このような状況を考慮し、本発明は、高い特性を有する電解質膜を形成できる補強材、それを用いた電解質膜および燃料電池、ならびに補強材の製造方法を提供することを目的の１つとする。
［０００７］
上記目的を達成するため検討した結果、本件発明者らは、ガラス繊維の表面にホスホシリケート系ゲルの被膜を形成することによって、高い特性を有する電解質膜を形成できる補強材が得られることを見出した。すなわち、本件発明者らは、ホスホシリケート系ゲルを含む繊維（たとえばホスホシリケート系ゲルで被覆されたガラス繊維）を補強材として用いることによって上記目的を達成できることを見出した。本件発明は、この新しい知見に基づく発明である。
【０００８】
本発明の電解質膜補強材は、ガラス繊維と前記ガラス繊維上に形成されたホスホシリケート系ゲルの被膜とを含む電解質膜補強材であって、前記被膜が、γ−グリシドキシプロピル基を含むホスホシリケート系ゲルである。
［０００９］
本発明の電解質膜は、補強材と前記補強材で補強された電解質とを含む電解質膜であって、前記補強材が本発明の電解質膜補強材である。
【００１０】
すなわち、本発明の電解質膜は、補強材と前記補強材で補強された電解質とを含む電解質膜であって、前記補強材が、ガラス繊維と前記ガラス繊維上に形成されたホスホシリケート系ゲルの被膜とを含み、前記被膜が、γ−グリシドキシプロピル基を含むホスホシリケート系ゲルである。
［００１１］
電解質膜補強材を製造するための本発明の方法は、（ｉ）以下の式（Ｉ）で表される少なくとも１種類の化合物と、リン酸構造を含む化合物とを含む出発材料からホスホシリケート系ゾルを調製する工程と、（ｉｉ）ガラス繊維の表面に前記ホスホシリケート系ゾルを塗布したのち、熱処理することによって前記ガラス繊維の表面にホスホシリケート系ゲルの被膜を形成する工程とを含み、前記出発材料が、以下の式（ＩＩ）で表される少なくとも１種類の化合物を含む。
Ｓｉ（ＯＲ）ｍＸ４−ｍ・・・（Ｉ）
［式（Ｉ）において、Ｒはアルキル基を示し、Ｘはハロゲン原子を示し、ｍは１以上４以下の整数を示す。］
Ｓｉ（ＯＲ２）ｓＸ２ ｔＺ４−ｓ−ｔ・・・（ＩＩ）
［式（ＩＩ）において、Ｒ２はアルキル基を示し、Ｘ２はハロゲン原子を示し、Ｚは、アルコキシ基およびハロゲン原子以外の有機基を示す。０≦ｓ≦３、０≦ｔ≦３、１≦ｓ＋ｔ≦３である。］
［００１２］
別の観点によれば、本発明は、電解質膜を補強するための補強材であって、プロトン伝導性を有する補強材を提供する。この電解質膜補強材は、ホスホシリケート系ゲルを含む繊維状の補強材である。
［００１３］
本発明の補強材はプロトン伝導性を有するため、補強材によるプロトン伝導性の低下を抑制できる。また、本発明の補強材では、ガラス繊維がホスホシリケート系ゲルの被膜で覆われているため、ガラス繊維の成分の溶出による特性の低下を抑制できる。本発明の補強材を用いることによって、プロトン伝導性や耐久性といった特性が高い電解質膜が得られる。
【発明を実施するための最良の形態】
【００１４】
以下、本発明の実施形態について説明する。
【００１５】
＜電解質膜補強材＞
本発明の電解質膜補強材は、ガラス繊維とガラス繊維上に形成されたホスホシリケート系ゲルの被膜とを含む。
【００１６】
ホスホシリケート系ゲルとは、リン酸構造を含む化合物が溶解した溶液中において、上述の式（Ｉ）で表される化合物を含む出発材料を加水分解縮合させることによって得られるゲルである。ホスホシリケート系ゲルには、上記加水分解縮合によって得られたゾルを熱処理することによって得られるゲルも含まれる。なお、出発材料は、式（Ｉ）で表される化合物の置換基の一部が有機基に置換された化合物や、シリコンアルコキシド以外の金属アルコキシドを含んでもよい。有機基を含有するシラン化合物を用いることによって、有機成分を含有するホスホシリケート系ゲルが得られる。ホスホシリケート系ゲルの製造方法の詳細については、後述する。
【００１７】
本発明の補強材では、導電性を有するホスホシリケート系ゲルの被膜によってガラス繊維が被覆されている。そのため、導電性を大きく低下させることなく、電解質膜を補強できる。また、ホスホシリケート系ゲルの被膜でガラス繊維を被覆することによって、ガラス繊維の金属成分（たとえばナトリウムなどのアルカリ金属）が溶出することを防止できる。
【００１８】
ガラス繊維の組成に特に限定はなく、たとえば、Ｅガラス組成、Ｓガラス組成、Ｃガラス組成、またはその他の組成であってもよい。補強材に用いられるガラス繊維は、１種類であってもよいし、複数種のガラス繊維を含んでもよい。Ｃガラス組成のガラス繊維は、耐酸性が高いため好ましい。また、Ｅガラス組成およびＳガラス組成のガラス繊維は、極細化が容易であるため好ましい。また、Ｅガラス組成のガラス繊維は安価であるため好ましい。
【００１９】
Ｅガラス組成の一般的な組成範囲を表１に示す。なお、Ｅガラス組成は、以下の表１に示す成分以外の微量成分を１種類以上含んでもよい。１つの微量成分の含有率は、通常、０．２質量％未満である（以下の表２および表３のガラス組成においても同様である）。
【００２０】
【表１】
また、Ｃガラス組成の一般的な組成範囲、および好ましい組成範囲を表２に示す。なお、Ｃガラス組成は、以下の表２に示す成分以外の微量成分を１種類以上含んでもよい。
【００２２】
【表２】
また、Ｓガラス組成の一般的な組成範囲を表３に示す。なお、Ｓガラス組成は、以下の表３に示す成分以外の微量成分を１種類以上含んでもよい。
【００２４】
【表３】
本発明の補強材では、ガラス繊維が布状のシート（以下、「ガラス繊維シート」という場合がある）を構成していてもよい。たとえば、ガラス繊維は、織布を構成していてもよいし不織布を構成していてもよい。この構成によれば、シート状の補強材が得られる。
【００２６】
ガラス繊維がガラス繊維シートを構成している場合、シートを構成しているガラス繊維同士が、被膜で結合されていてもよい。繊維の交絡部分がホスホシリケート系ゲルの被膜で固定および補強されることによって、強度が高い補強材が得られる。なお、補強材は、ガラス繊維シートを構成しない複数の単繊維であってもよい。
【００２７】
本発明の補強材がシート状である場合、その空隙率は、通常、６０体積％〜９８体積％の範囲であり、好ましくは８０体積％〜９８体積％の範囲であり、より好ましくは８５体積％〜９５体積％の範囲（たとえば９０体積％〜９５体積％の範囲）である。補強材の空隙率は、ガラス繊維のサイズ、単位体積あたりのガラス繊維の量、被膜の量などによって制御できる。空隙率が９８体積％を越えると、強度が大きく低下する。一方、空隙率が６０体積％未満であると、可撓性が低下し、組み立て時や加圧時に、電解質膜が損傷しやすくなる。なお、空隙率Ｖ（体積％）は、以下の式で求められる。
Ｖ（体積％）＝［１−Ｗ／ｔ×｛（１−ｃＢ）／ρＧ＋ｃＢ／ρＢ｝］×１００
ｔ：２０ｋＰａの圧力でシートを加圧したときのシートの厚さ
Ｗ：シートの単位面積あたりの質量
ρＧ：ガラス繊維の密度（約２．５×１０3ｋｇ／ｍ3）
ρＢ：ホスホシリケート系ゲルの被膜の密度
ｃＢ：シートの質量に占めるホスホシリケート系ゲルの被膜の質量比率
【００２８】
なお、ホスホシリケート系ゲルの被膜の密度ρＢは、ホスホシリケート系ゲルの塊を被膜と同じ条件で作製して測定した。また、ホスホシリケート系ゲルの被膜の質量比率ｃＢは、被膜形成前のシートの質量と、被膜形成後のシートの質量とを測定することによって算出した。
【００２９】
本発明の補強材がシート状である場合、その厚さは、たとえば１００μｍ以下であり、好ましくは５０μｍ以下である。なお、この厚さは、２０ｋＰａの圧力で加圧されたシートの厚さをダイヤルゲージで測定した値である。
【００３０】
また、本発明の補強材がシート状である場合、その目付（単位面積あたりの質量）は、たとえば２ｇ／ｍ2〜５０ｇ／ｍ2の範囲であり、一例では３ｇ／ｍ2〜２５ｇ／ｍ2の範囲である。
【００３１】
また、ガラス繊維は、布状のシートを構成しない短繊維であってもよい。この場合、ガラス繊維は電解質中に分散される。
【００３２】
ガラス繊維の平均径および平均繊維長は、目的とする強度、補強材の形状、ガラス組成といった条件に応じて選択される。ガラス繊維の平均径の一例は、０．１μｍ〜２０μｍの範囲にあってもよい。また、ガラス繊維の平均長さの一例は、０．５ｍｍ〜２０ｍｍの範囲にあってもよい。
【００３３】
ホスホシリケート系ゲル（リン珪酸系ガラス）の被膜は、たとえばゾル・ゲル法で形成できる。ホスホシリケート系ゲルの被膜の量は、たとえば補強材全体の１質量％〜９０質量％の範囲（たとえば、２質量％〜３０質量％の範囲）である。ホスホシリケート系ゲルの被膜の製造方法については後述する。
【００３４】
ホスホシリケート系ゲルの被膜の表面は、シランカップリング剤で処理されていてもよい。シランカップリング剤で処理することによって、補強材と電解質との結合力が増大する。補強材と電解質との熱膨張率が異なる場合、補強材と電解質との結合が弱いと、温度変化によって補強材と電解質とが剥離することがある。その結果、電解質膜中の水のクラスターが分断または変形し、プロトン伝導性が低下する場合がある。シランカップリング剤を用いて補強材と電解質との結合力を高めることによって、そのようなプロトン伝導性の低下を抑制できる。シランカップリング剤の一例としては、たとえば、アミノシラン、メタクリルシラン、エポキシシラン、ビニルシラン、メルカプトシラン、イソシアネートシラン、フルオロシランが挙げられる。
［００３５］
被膜は、有機成分を含むホスホシリケート系ゲルである。このホスホシリケート系ゲルについては、後述する。
［００３６］
＜電解質膜＞
本発明の電解質膜（プロトン伝導性膜）は、上記本発明の補強材と、その補強材で補強された電解質とを含む。
［００３７］
電解質には、いわゆる固体電解質といわれるものが適用でき、たとえば、高分子電解質、無機−有機複合電解質、無機電解質を適用できる。
［００３８］
電解質は、高分子電解質であってもよい。高分子電解質に特に限定はないが、たとえば、パーフルオロアルキレンを主骨格とし、パーフルオロビニルエーテル側鎖を有し、一部の側鎖の末端にスルホン酸基やカルボン酸基等のイオン交換基を有するフッ素系高分子を用いることができる。フッ素系高分子としては、たとえば、デュポン社のナフィオン（Ｎａｆｉｏｎ：登録商標）、旭化成工業株式会社のアシプレックス（Ａｃｉｐｌｅｘ：登録商標）、旭硝子株式会社のフレミオン（Ｆｌｅｍｉｏｎ：登録商標）などを用いてもよい。
［００３９］
電解質膜全体に占める補強材の割合は、たとえば２体積％〜４０体積％の範囲であってもよい。また、電解質膜の厚さは、たとえば１００μｍ以下であり、好ましくは５０μｍ以下であってもよい。
［００４０］
＜燃料電池＞
本発明の燃料電池は、本発明の電解質膜を備える。電解質膜以外の部分については特に限定はなく、任意の材料および構成を適用できる。本発明の燃料電池の好ましい一例は、公知の高分子電解質型燃料電池の電解質膜を本発明の電解質膜に置き換えて得られる燃料電池である。この場合、電解質膜以外の部分には、公知の高分子電解質型燃料電池の材料および構成を適用でき、公知の方法で製造できる。
［００４１］
＜電解質膜の補強材の製造方法＞
以下に、電解質膜の補強材を製造するための本発明の方法の一例を説明する。この方法によれば、本発明の補強材が得られる。
［００４２］
まず、以下の式（Ｉ）で表される少なくとも１種類の化合物（以下、化合物（Ａ）という場合がある）と、リン酸構造を含む化合物とを含む出発材料からホスホシリケート系ゾルを調製する（工程（ｉ））。
Ｓｉ（ＯＲ）ｍＸ４−ｍ・・・（Ｉ）
［式（Ｉ）において、Ｒはアルキル基を示し、Ｘはハロゲン原子を示し、ｍは１以上４以下の整数を示す。］
［００４３］
式（Ｉ）のＲは、メチル基やエチル基といった、炭素数が５以下のアルキル基である。Ｘは、塩素、フッ素、臭素といったハロゲン原子である。式（Ｉ）の化合物は、加水分解縮合によってゾルとなる化合物であり、典型的には、テトラアルコキシシランである。
［００４４］
テトラアルコキシシランとしては、たとえば、テトラメトキシシラン、テトラエトキシシラン、テトラプロポキシシラン、テトラブトキシシランなどが挙げられる。
［００４５］
この明細書においてリン酸構造には、「ＰＯ４」や「ＰＯ３」といった構造が含まれる。通常、リン酸構造として「ＰＯ４（リン酸イオン：ＰＯ４ ３−）」を含む化合物が用いられる。すなわち、リン酸構造を含む化合物（以下、「リン酸化合物」という場合がある）としては、通常、リン酸（Ｐ２Ｏ５・ｎＨ２Ｏ）が用いられ、たとえばオルトリン酸（Ｈ３ＰＯ４）が用いられる。また、リン酸化合物として、メタリン酸（ＨＰＯ３）やピロリン酸（Ｈ４Ｐ２Ｏ７）を用いてもよい。
［００４６］
ホスホシリケート系ゾルは、化合物（Ａ）とリン酸化合物とを含む溶液中で加水分解縮合を生じさせる方法で形成してもよいし、化合物（Ａ）を部分的に加水分解縮合させたのち、リン酸化合物を加えてさらに加水分解縮合させる方法で形成してもよい。加水分解縮合は、公知のゾル・ゲル法で用いられる方法、たとえば、水と酸触媒と必要に応じてアルコールとを含む溶液中で反応させる方法で行うことができる。なお、後述するように、化合物（Ａ）に加えて、化学式（Ｉ）の置換基の一部が有機基Ｚである化合物を加水分解縮合させる。
［００４７］
次に、ガラス繊維の表面に、上記ホスホシリケート系ゾルを塗布したのち、熱処理することによってガラス繊維の表面にホスホシリケート系ゲルの被膜を形成する（工程（ｉｉ））。
［００４８］
ガラス繊維には、上述したガラス繊維を用いることができる。上述したように、このガラス繊維は、布状のシート（ガラス繊維シート）を構成していてもよい。
［００４９］
被膜は、たとえば、平板上に所定量のホスホシリケート系ゾルを滴下し、常圧または減圧下でガラス繊維（たとえばガラス繊維シート）をゾルに浸漬し、その状態で乾燥および熱処理を行うことによって形成してもよい。この方法では、ゾルの濃度および滴下量によって、被膜の量を制御できる。また、被膜は、ホスホシリケート系ゾルの中にガラス繊維を浸漬したのち、引き上げて乾燥および熱処理を行うことによって形成してもよい。この方法では、ゾルの濃度およびガラス繊維の引き上げ速度によって、被膜の量を制御できる。
［００５０］
なお、被膜の量は、ガラス繊維に含浸させるゾルの量で制御してもよいし、工程（ｉｉ）を複数回繰り返すことによって制御してもよい。
［００５１］
ゾルの乾燥は、２０℃〜７０℃の温度で行うことが好ましい。乾燥後の熱処理は、１００℃以上の温度で行うことが好ましく、たとえば１００℃〜３５０℃の範囲で行ってもよい。
［００５２］
なお、ホスホシリケート系ゾルの材料は、化合物（Ａ）に加えて、式（Ｉ）の置換基の一部が他の置換基である化合物をさらに含む。式（Ｉ）の４つの置換基のうちの一部（たとえば１つ）が有機基である化合物を加えることによって、有機成分を含むホスホシリケート系ゲルの被膜を形成できる。この場合、出発材料は、化合物（Ａ）に加えて以下の式（ＩＩ）で表される少なくとも１種類の化合物を含む。
Ｓｉ（ＯＲ２）ｓＸ２ ｔＺ４−ｓ−ｔ・・・（ＩＩ）
［式（ＩＩ）において、Ｒ２はアルキル基を示し、Ｘ２はハロゲン原子を示し、Ｚは、アルコキシ基およびハロゲン原子以外の有機基を示す。０≦ｓ≦３、０≦ｔ≦３、１≦ｓ＋ｔ≦３である。］
［００５３］
Ｒ２およびＸ２には、それぞれ、式（Ｉ）のＲおよびＸについて説明したアルキル基またはハロゲン原子を適用できる。有機基Ｚとしては、たとえば、エポキシ基、アミノ基、アクリル基などを含む有機基が挙げられ、具体的には、γ−グリシドキシプロピル基などを用いることができる。
［００５４］
リン酸構造を含む化合物が溶解している溶液中で、化合物（Ａ）と化学式（ＩＩ）で表される少なくとも１種類の化合物とを加水分解縮合させることによって、有機成分を含むホスホシリケート系ゲルの被膜を形成できる。
【００５５】
ただし、有機成分（アルキル鎖など）を実質的に含まないホスホシリケート系ゲルのプロトン伝導度は、有機成分を含むホスホシリケート系ゲルのプロトン伝導度の１０倍程度である。そのため、伝導度の点では、式（Ｉ）の化合物とリン酸とを用いて、有機成分を実質的に含まないホスホシリケート系ゾルを調製することが好ましい。一方、有機成分を含むホスホシリケート系ゲルの被膜は、無機成分のみのホスホシリケート系ゲルに比べて靱性が高いため、引っ張り強度がより高い補強材を得ることができるという点で好ましい。
【００５６】
なお、ホスホシリケート系ゲルの出発材料は、アルコキシアルミニウムなどの他の金属アルコキシドを含んでもよい。ただし、他の金属アルコキシドの量（モル量）は、化学式（Ｉ）で表される化合物および化学式（II）で表される化合物の合計の量（モル量）よりも少ない。
【００５７】
＜電解質膜の製造方法＞
補強材がガラス繊維シートである場合、ガラス繊維シートの空隙に電解質を配置することによって電解質膜が得られる。たとえば、電解質の溶液、分散液またはゾルをガラス繊維シートに含浸させたのち、乾燥すればよい。なお、乾燥後に必要に応じて熱処理をしてもよい。
【００５８】
補強材がガラス繊維シートであり電解質が高分子電解質である場合には、たとえば、高分子電解質の溶液または分散液にガラス繊維シートを浸漬したのち、乾燥すればよい。たとえば、まず、フッ素系ポリマー電解質（高分子電解質）の分散液を準備し、これをイソプロピルアルコールで希釈した溶液を、ガラス繊維シートに含浸させる。その後、電解質の溶液が含浸したガラス繊維シートを乾燥および熱処理することによって、電解質膜が得られる。
【００５９】
補強材がガラス繊維シートではなく単繊維の集合体である場合、電解質の溶液、分散液またはゾルと複数の単繊維とを混合したのち乾燥することによって、単繊維で補強された電解質膜を得ることができる。このとき、必要に応じて乾燥後に熱処理を行ってもよい。たとえば、高分子電解質を含む溶液または分散液と複数の単繊維とを混合したのち、混合液を膜状にのばし、乾燥（必要に応じて熱処理）することによって電解質膜が得られる。
【実施例】
［００６０］
以下、実施例および比較例によって本発明をさらに具体的に説明するが、本発明は、以下の実施例に限定されない。なお、以下の実施例では、表４に示すＣガラス組成を有するガラス繊維を用いたが、上述した他のガラス繊維を用いてもよい。
［００６１］
【表４】
［参考例１］
表４に示したＣガラス組成を有し、平均直径０．７μｍで平均長さ約３ｍｍのガラス短繊維を用意した。このガラス繊維を、繊維を解きほぐすためのパルパーに投入し、硫酸でｐＨ２．５に調整した水溶液中で充分に解離、分散させた。このようにして、ガラス繊維分散液を作製した。
［００６３］
このガラス繊維分散液から、湿式抄紙装置を用いて、ガラス繊維の不織布（１）を作製した。不織布（１）は、厚さが９０μｍであり、目付量は１４ｇ／ｍ２であった。不織布（１）の空隙率は、約９５体積％であった。
［００６４］
次に、不織布（１）のガラス繊維上に、ホスホシリケート系ゲルの被膜を以下の方法で形成した。まず、テトラエトキシシラン、オルトリン酸、エタノール、および純水を、モル比でおよそ１：１：５：３の割合で混合し、２時間撹拌して、ホスホシリケート系ゾルを得た。このゾルをポリオレフィン製トレイに適量注ぎ、ゾル中にガラス繊維不織布（１）を浸漬した。その後、不織布をゾルから引き上げて乾燥および熱処理した。このようにして、ホスホシリケート系ゲルの被膜が形成されたガラス繊維不織布（２）を得た。
［００６５］
ホスホシリケート系ゲルの被膜の体積は、ガラス繊維の体積の約５％であった。また、ガラス繊維不織布（２）の空隙率は約９４．８体積％であった。
［００６６］
つぎに、不織布（２）を用いてプロトン伝導性膜を作製した。まず、フッ素系ポリマー電解質の分散液（ナフィオンＤＥ２０２０：デュポン社製）をイソプロピルアルコールで希釈した液を、不織布（２）に含浸させ、１２時間以上自然乾燥した。その後、１２０℃で１時間熱処理した後、ホットプレス装置にて１２０℃、１０ＭＰａでプレスした。このようにして、プロトン伝導性膜を得た。なお、電解質分散液の濃度および含浸量は、熱プレス後の膜の厚さが８０μｍになるように調整した。
［００６７］
［参考例２〜４］
ガラス繊維に形成されるホスホシリケート系ゲルの被膜の体積を変更させたことを除き、参考例１と同様の方法で、被膜が形成されたガラス繊維不織布（２）を形成した。ホスホシリケート系ゲルの被膜の体積は、ガラス繊維の体積に対し、参考例２で約１０％、参考例３で約４０％、参考例４で約６０％とした。
［００６８］
被膜の体積は、ガラス繊維不織布（１）に含浸させるホスホシリケート系ゾルの量を変化させることによって制御した。
［００６９］
形成された不織布（２）の空隙率は、参考例２で約９４．５％、参考例３で約９３％、参考例４で約９２％であった。これらの不織布（２）を用い、参考例１と同じ手順でプロトン伝導性膜を形成した。
［００７０］
［実施例５］
参考例１で説明したガラス繊維不織布（１）のガラス繊維上に、有機成分を含有するホスホシリケート系ゲルの被膜を、以下の方法で形成した。まず、テトラエトキシシラン、γ−グリシドキシプロピルトリメトキシシラン、オルトリン酸、エタノール、および純水を、モル比でおよそ０．２５：０．７５：１：５：３の割合で混合し、２時間撹拌して、有機成分を含有するホスホシリケート系ゾルを得た。このゾルをポリオレフィン製トレイに適量注ぎ、ゾル中にガラス繊維不織布（１）を浸漬した。その後、不織布（１）をトレイに入れたまま２０〜７０℃でゾルを乾燥させ、次に、トレイから平滑なガラス板上に移して１２０〜２００℃で熱処理した。このようにして、有機成分を含有するホスホシリケート系ゲルの被膜が形成されたガラス繊維不織布（２）を得た。
［００７１］
ホスホシリケート系ゲルの被膜の体積は、ガラス繊維の体積の約５％であった。また、ガラス繊維不織布（２）の空隙率は約９４．８体積％であった。これらの不織布（２）を用い、参考例１と同じ手順でプロトン伝導性膜を形成した。
［００７２］
［実施例６〜９］
ガラス繊維に形成される被膜の体積を変更させたことを除き、実施例５と同様の方法で、有機成分を含有するホスホシリケート系ゲルの被膜が形成されたガラス繊維不織布（２）を形成した。有機成分を含有するホスホシリケート系ゲルの被膜の体積は、ガラス繊維の体積に対し、実施例６で約１０％、実施例７で約４０％、実施例８で約６０％、実施例９で約２００％とした。
［００７３］
被膜の体積は、ゾルの体積を調節することによって変更した。
［００７４］
得られた不織布（２）の空隙率は、実施例６で約９４．５％、実施例７で約９３％、実施例８で約９２％、実施例９で約８５％であった。これらの不織布（２）を用い、参考例１と同じ手順でプロトン伝導性膜を形成した。
［００７５］
［実施例１０］
表４に示したＣガラス組成を有し、平均直径０．７μｍで平均長さ約３ｍｍのガラス短繊維を用意した。このガラス繊維を、繊維を解きほぐすためのパルパーに投入し、硫酸でｐＨ２．５に調整した水溶液中で充分に解離、分散させた。このようにして、ガラス繊維分散液を作製した。
［００７６］
このガラス繊維分散液から、湿式抄紙装置を用いて、ガラス繊維のシートを形成し、さらに乾燥前にプレスすることによって、ガラス繊維不織布（１）を作製した。ガラス繊維不織布（１）は、厚さが９０μｍであり、目付量は３０ｇ／ｍ２であった。このガラス繊維不織布の空隙率は、約８７体積％であった。
［００７７］
次に、ガラス繊維不織布（１）のガラス繊維上に、有機成分を含有するホスホシリケート膜を、以下の方法で形成した。まず、テトラエトキシシラン、オルトリン酸、エタノール、および純水を、モル比でおよそ１：１：５：３の割合で混合し、２時間撹拌して、ホスホシリケート系ゾルを得た。このゾルをポリオレフィン製トレイに適量注ぎ、ゾル中にガラス繊維不織布（１）を含浸した。その後、不織布をゾルから引き上げて乾燥および熱処理した。このようにして、有機成分を含有するホスホシリケート系ゲルの被膜が形成されたガラス繊維不織布（２）を得た。ホスホシリケート系ゲルの被膜の体積は、ガラス繊維の体積の約５％であった。また、ガラス繊維不織布（２）の空隙率は約８６体積％であった。この不織布（２）を用い、参考例１と同じ手順でプロトン伝導性膜を形成した。
［００７８］
［比較例１］
参考例１で用いた電解質分散液を、底面の平坦性の良好なガラス製シャーレに入れ、１２時間以上自然乾燥し、その後、１２０℃で１時間熱処理して膜状にした。この膜状の電解質を、ホットプレス装置によって１２０℃、１０ＭＰａでプレスし、プロトン伝導性膜を得た。電解質分散液の濃度は参考例１と同様とし、液量は、熱プレス後の膜の厚さが８０μｍになるように調整した。
［００７９］
［比較例２］
参考例１で説明したガラス繊維不織布（１）を、被膜を形成せずにそのまま補強材として用いることを除き、参考例１と同様の方法でプロトン伝導性膜を形成した。なお、電解質分散液の濃度および含浸量は、熱プレス後の膜の厚さが８０μｍになるように調整した。
［００８０］
［補強材およびプロトン伝導性膜の評価］
上述の参考例１〜４および実施例５〜１０および比較例１〜２において作製した補強材、およびプロトン伝導性膜について、以下の測定を行った。なお、参考例１〜４および実施例５〜１０の補強材は、被膜を備えるガラス繊維不織布（２）であり、比較例２の補強材は、被膜を備えないガラス繊維不織布（１）である。
［００８１］
［補強材の厚さ］
補強材を約２０ｋＰａの圧力でプレスした状態で、シックネスゲージを用いて補強材の厚さを測定した。
［００８２］
［プロトン伝導性膜の厚さ］
マイクロメータを用いて測定した。
［００８３］
［補強材およびプロトン伝導性膜の引張強度測定］
補強材および電解質膜を、それぞれ、幅２０ｍｍ×長さ８０ｍｍに切断して試験片を作製した。この試験片を、チャック間隔３０ｍｍでチャックし、１０ｍｍ／分の速度で引っ張って、破断時の荷重（Ｎ）を測定した。この測定値を、サンプル厚さおよび幅の実測値で除して、引張強度（ＭＰａ）を算出した。
［００８４］
［プロトン伝導性］
インピーダンスアナライザを用い、プロトン伝導性膜の厚さ方向のプロトン伝導度（Ｓ／ｍ）を測定した。
［００８５］
以上の測定結果を表５に示す。
［００８６］
【表５】
表５から明らかなように、参考例１〜４および実施例５〜１０の補強材は、比較例２の補強材に比べて、引張強度が高かった。また、参考例１〜４および実施例５〜１０のプロトン伝導性膜は、比較例のプロトン伝導性膜と比べて、プロトン伝導度が同等であり引張強度が高かった。
【産業上の利用可能性】
［００８８］
本発明は、燃料電池に用いられる電解質膜の補強材、ならびにそれを用いた電解質膜および燃料電池に適用できる。また、本発明は、電解質膜補強材の製造方法に適用できる。【Technical field】
[0001]
The present invention relates to an electrolyte membrane reinforcing material, an electrolyte membrane using the same, a fuel cell, and a method for producing an electrolyte membrane reinforcing material.
[Background]
[0002]
Fuel cells are characterized by high power generation efficiency and low environmental impact. Among the fuel cells, the polymer electrolyte fuel cell (PEFC) can be easily reduced in size and weight with high output, and can also be reduced in cost due to the mass production effect. Therefore, PEFC is expected as a small-scale on-site type, automobile, and portable fuel cell.
[0003]
Currently, mainly used as polymer proton conductive membranes (polymer electrolyte membranes) are fluorine-based polymers containing perfluoroalkylene chains as the main skeleton and containing ion-exchange groups such as sulfonic acid groups and carboxylic acid groups. It is a polymer film. However, these fluorinated polymer membranes swell with water content, resulting in an increase in size, a decrease in mechanical strength, and a creep during long-time operation. Therefore, the fluoropolymer film alone has a problem that handling property at the time of cell formation and durability after the start of operation are low.
[0004]
In order to solve such problems, attempts have been made to reinforce polymer membranes with various reinforcing materials, for example, electrolyte membranes using glass fibers have been proposed (for example, Japanese Patent Application Laid-Open No. 10-312815, JP 2004-047450 A, JP 2004-319421 A).
[0005]
However, since the glass fiber itself does not have proton conductivity, there is a problem that the proton conductivity of the electrolyte membrane decreases as the amount of the reinforcing material increases. For this reason, it has been difficult to obtain a reinforcing material having high strength while maintaining proton conductivity.
DISCLOSURE OF THE INVENTION
[0006]
In view of such circumstances, it is an object of the present invention to provide a reinforcing material capable of forming an electrolyte membrane having high characteristics, an electrolyte membrane using the same, a fuel cell, and a method for manufacturing the reinforcing material. .
[0007]
As a result of studies to achieve the above object, the present inventors have found that a reinforcing material capable of forming an electrolyte membrane having high characteristics can be obtained by forming a phosphosilicate gel film on the surface of glass fiber. It was. That is, the present inventors have found that the above object can be achieved by using a fiber containing a phosphosilicate gel (for example, a glass fiber coated with a phosphosilicate gel) as a reinforcing material. The present invention is based on this new finding.
[0008]
The electrolyte membrane reinforcing material of the present invention is an electrolyte membrane reinforcing material comprising glass fiber and a phosphosilicate gel film formed on the glass fiber, the coating film comprising:γ-glycidoxypropyl groupIs a phosphosilicate-based gel containing
[0009]
The electrolyte membrane of the present invention is an electrolyte membrane including a reinforcing material and an electrolyte reinforced with the reinforcing material, and the reinforcing material is the electrolyte membrane reinforcing material of the present invention.
[0010]
That is, the electrolyte membrane of the present invention is an electrolyte membrane containing a reinforcing material and an electrolyte reinforced with the reinforcing material, and the reinforcing material is made of glass fiber and a phosphosilicate gel formed on the glass fiber. A coating, wherein the coating isγ-glycidoxypropyl groupIs a phosphosilicate-based gel containing
[0011]
The method of the present invention for producing an electrolyte membrane reinforcement comprises a phosphosilicate system from a starting material comprising (i) at least one compound represented by the following formula (I) and a compound containing a phosphate structure: A step of preparing a sol, and (ii) a step of forming a phosphosilicate gel film on the surface of the glass fiber by applying a heat treatment after the phosphosilicate sol is applied to the surface of the glass fiber, The starting material contains at least one compound represented by the following formula (II).
Si (OR)mX4-m... (I)
[In the formula (I), R represents an alkyl group, X represents a halogen atom, and m represents an integer of 1 to 4. ]
Si (OR2)sX2 tZ4-s-t... (II)
[In formula (II), R2Represents an alkyl group, X2Represents a halogen atom, and Z represents an organic group other than an alkoxy group and a halogen atom. 0 ≦ s ≦ 3, 0 ≦ t ≦ 3, and 1 ≦ s + t ≦ 3. ]
[0012]
According to another aspect, the present invention provides a reinforcing material for reinforcing an electrolyte membrane, which has proton conductivity. This electrolyte membrane reinforcing material is a fibrous reinforcing material containing a phosphosilicate gel.
[0013]
Since the reinforcing material of the present invention has proton conductivity, a decrease in proton conductivity due to the reinforcing material can be suppressed. Moreover, in the reinforcing material of this invention, since the glass fiber is covered with the film of the phosphosilicate type gel, the fall of the characteristic by the elution of the component of glass fiber can be suppressed. By using the reinforcing material of the present invention, an electrolyte membrane having high characteristics such as proton conductivity and durability can be obtained.
BEST MODE FOR CARRYING OUT THE INVENTION
[0014]
Hereinafter, embodiments of the present invention will be described.
[0015]
<Electrolyte membrane reinforcement>
The electrolyte membrane reinforcing material of the present invention includes glass fibers and a phosphosilicate gel film formed on the glass fibers.
[0016]
A phosphosilicate gel is a gel obtained by hydrolytic condensation of a starting material containing a compound represented by the above formula (I) in a solution in which a compound containing a phosphoric acid structure is dissolved. The phosphosilicate gel includes a gel obtained by heat-treating the sol obtained by the hydrolysis condensation. Note that the starting material may include a compound in which a part of the substituents of the compound represented by the formula (I) is substituted with an organic group, or a metal alkoxide other than silicon alkoxide. By using a silane compound containing an organic group, a phosphosilicate gel containing an organic component can be obtained. Details of the method for producing the phosphosilicate gel will be described later.
[0017]
In the reinforcing material of the present invention, the glass fiber is coated with a film of conductive phosphosilicate gel. Therefore, the electrolyte membrane can be reinforced without greatly reducing the conductivity. Moreover, it can prevent that the metal component (for example, alkali metals, such as sodium) of glass fiber elutes by coat | covering glass fiber with the film of a phosphosilicate type gel.
[0018]
There is no limitation in particular in the composition of glass fiber, For example, E glass composition, S glass composition, C glass composition, or another composition may be sufficient. One type of glass fiber used for the reinforcing material may be included, or a plurality of types of glass fibers may be included. A glass fiber having a C glass composition is preferable because of high acid resistance. Further, glass fibers having an E glass composition and an S glass composition are preferable because they can be easily made ultrafine. Moreover, since the glass fiber of E glass composition is cheap, it is preferable.
[0019]
Table 1 shows a general composition range of the E glass composition. The E glass composition may contain one or more trace components other than the components shown in Table 1 below. The content of one trace component is usually less than 0.2% by mass (the same applies to the glass compositions in Tables 2 and 3 below).
[0020]
[Table 1]
Table 2 shows a general composition range of the C glass composition and a preferred composition range. The C glass composition may contain one or more trace components other than those shown in Table 2 below.
[0022]
[Table 2]
Table 3 shows a general composition range of the S glass composition. The S glass composition may contain one or more trace components other than the components shown in Table 3 below.
[0024]
[Table 3]
In the reinforcing material of the present invention, the glass fiber may constitute a cloth-like sheet (hereinafter sometimes referred to as “glass fiber sheet”). For example, the glass fiber may constitute a woven fabric or a non-woven fabric. According to this configuration, a sheet-like reinforcing material is obtained.
[0026]
When glass fibers constitute a glass fiber sheet, the glass fibers constituting the sheet may be bonded with a coating. A reinforcing material having a high strength can be obtained by fixing and reinforcing the entangled portion of the fiber with a phosphosilicate gel coating. The reinforcing material may be a plurality of single fibers that do not constitute a glass fiber sheet.
[0027]
When the reinforcing material of the present invention is in the form of a sheet, the porosity is usually in the range of 60 volume% to 98 volume%, preferably in the range of 80 volume% to 98 volume%, more preferably 85 volume. % To 95% by volume (for example, 90% to 95% by volume). The porosity of the reinforcing material can be controlled by the glass fiber size, the amount of glass fiber per unit volume, the amount of coating, and the like. When the porosity exceeds 98% by volume, the strength is greatly reduced. On the other hand, when the porosity is less than 60% by volume, flexibility is lowered, and the electrolyte membrane is easily damaged during assembly and pressurization. In addition, the porosity V (volume%) is calculated | required with the following formula | equation.
V (volume%) = [1-W / t × {(1-cB) / ρG + cB / ρB}] × 100
t: sheet thickness when the sheet is pressed at a pressure of 20 kPa
W: Mass per unit area of the sheet
ρG: Density of glass fiber (about 2.5 × 10Threekg / mThree)
ρB: Density of phosphosilicate gel film
cB: Mass ratio of the phosphosilicate gel film to the sheet mass
[0028]
The density ρB of the phosphosilicate gel film was measured by preparing a lump of the phosphosilicate gel under the same conditions as the film. Moreover, the mass ratio cB of the coating film of the phosphosilicate gel was calculated by measuring the mass of the sheet before forming the coating film and the mass of the sheet after forming the coating film.
[0029]
When the reinforcing material of the present invention is in the form of a sheet, the thickness thereof is, for example, 100 μm or less, preferably 50 μm or less. This thickness is a value obtained by measuring the thickness of a sheet pressed with a pressure of 20 kPa with a dial gauge.
[0030]
Further, when the reinforcing material of the present invention is in sheet form, the basis weight (mass per unit area) is, for example, 2 g / m.2~ 50g / m2In the example, 3 g / m2~ 25g / m2Range.
[0031]
Moreover, the short fiber which does not comprise a cloth-like sheet may be sufficient as glass fiber. In this case, the glass fiber is dispersed in the electrolyte.
[0032]
The average diameter and the average fiber length of the glass fibers are selected according to conditions such as the intended strength, the shape of the reinforcing material, and the glass composition. An example of the average diameter of the glass fiber may be in the range of 0.1 μm to 20 μm. Moreover, an example of the average length of glass fiber may exist in the range of 0.5 mm-20 mm.
[0033]
A film of phosphosilicate gel (phosphosilicate glass) can be formed by, for example, a sol-gel method. The amount of the phosphosilicate gel coating is, for example, in the range of 1% by mass to 90% by mass of the entire reinforcing material (for example, in the range of 2% by mass to 30% by mass). A method for producing a phosphosilicate gel film will be described later.
[0034]
The surface of the phosphosilicate gel film may be treated with a silane coupling agent. By treating with a silane coupling agent, the bonding strength between the reinforcing material and the electrolyte increases. When the thermal expansion coefficients of the reinforcing material and the electrolyte are different, if the bond between the reinforcing material and the electrolyte is weak, the reinforcing material and the electrolyte may be peeled off due to a temperature change. As a result, water clusters in the electrolyte membrane may be divided or deformed, and proton conductivity may be reduced. By increasing the bonding strength between the reinforcing material and the electrolyte using a silane coupling agent, such a decrease in proton conductivity can be suppressed. Examples of the silane coupling agent include amino silane, methacryl silane, epoxy silane, vinyl silane, mercapto silane, isocyanate silane, and fluorosilane.
[0035]
The coating is a phosphosilicate gel containing an organic component. This phosphosilicate gel will be described later.
[0036]
<Electrolyte membrane>
The electrolyte membrane (proton conductive membrane) of the present invention includes the reinforcing material of the present invention and an electrolyte reinforced with the reinforcing material.
[0037]
As the electrolyte, what is called a solid electrolyte can be applied, and for example, a polymer electrolyte, an inorganic-organic composite electrolyte, and an inorganic electrolyte can be applied.
[0038]
The electrolyte may be a polymer electrolyte. The polymer electrolyte is not particularly limited. For example, it has perfluoroalkylene as the main skeleton, has a perfluorovinyl ether side chain, and has an ion exchange group such as a sulfonic acid group or a carboxylic acid group at the end of a part of the side chain. The fluoropolymer which has can be used. As the fluorine-based polymer, for example, Nafion (registered trademark) manufactured by DuPont, Aciplex (registered trademark) manufactured by Asahi Kasei Kogyo Co., Ltd., Flemion (registered trademark) manufactured by Asahi Glass Co., Ltd. may be used. Good.
[0039]
The ratio of the reinforcing material to the entire electrolyte membrane may be, for example, in the range of 2% to 40% by volume. Further, the thickness of the electrolyte membrane is, for example, 100 μm or less, and preferably 50 μm or less.
[0040]
<Fuel cell>
The fuel cell of the present invention includes the electrolyte membrane of the present invention. There are no particular limitations on the portions other than the electrolyte membrane, and any material and configuration can be applied. A preferred example of the fuel cell of the present invention is a fuel cell obtained by replacing the electrolyte membrane of a known polymer electrolyte fuel cell with the electrolyte membrane of the present invention. In this case, the material and configuration of a known polymer electrolyte fuel cell can be applied to portions other than the electrolyte membrane, and can be manufactured by a known method.
[0041]
<Method for producing electrolyte membrane reinforcing material>
Below, an example of the method of this invention for manufacturing the reinforcement material of an electrolyte membrane is demonstrated. According to this method, the reinforcing material of the present invention can be obtained.
[0042]
First, a phosphosilicate sol is prepared from a starting material containing at least one compound represented by the following formula (I) (hereinafter sometimes referred to as compound (A)) and a compound containing a phosphoric acid structure. (Step (i)).
Si (OR)mX4-m... (I)
[In the formula (I), R represents an alkyl group, X represents a halogen atom, and m represents an integer of 1 to 4. ]
[0043]
R in the formula (I) is an alkyl group having 5 or less carbon atoms, such as a methyl group or an ethyl group. X is a halogen atom such as chlorine, fluorine or bromine. The compound of the formula (I) is a compound that becomes a sol by hydrolysis condensation, and is typically tetraalkoxysilane.
[0044]
Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane.
[0045]
In this specification, the phosphate structure includes “PO”.4Or PO3Is included. Usually, “PO”4(Phosphate ion: PO4 3-) "Is used. That is, as a compound having a phosphoric acid structure (hereinafter sometimes referred to as “phosphoric acid compound”), phosphoric acid (P2O5・ NH2O), for example orthophosphoric acid (H3PO4) Is used. Further, as a phosphoric acid compound, metaphosphoric acid (HPO3) And pyrophosphate (H4P2O7) May be used.
[0046]
The phosphosilicate sol may be formed by a method in which hydrolysis condensation occurs in a solution containing the compound (A) and the phosphate compound, or after partially hydrolyzing and condensing the compound (A), You may form by the method of adding a phosphoric acid compound and carrying out the hydrolysis condensation further. Hydrolytic condensation can be performed by a method used in a known sol-gel method, for example, a method of reacting in a solution containing water, an acid catalyst, and if necessary, an alcohol. As will be described later, in addition to the compound (A), a compound in which a part of the substituent of the chemical formula (I) is an organic group Z is hydrolytically condensed.
[0047]
Next, after applying the phosphosilicate sol to the surface of the glass fiber, heat treatment is performed to form a phosphosilicate gel film on the surface of the glass fiber (step (ii)).
[0048]
The glass fiber mentioned above can be used for the glass fiber. As described above, this glass fiber may constitute a cloth-like sheet (glass fiber sheet).
[0049]
The coating is formed, for example, by dropping a predetermined amount of a phosphosilicate sol onto a flat plate, immersing glass fibers (for example, a glass fiber sheet) in the sol under normal pressure or reduced pressure, and performing drying and heat treatment in that state. May be. In this method, the amount of coating can be controlled by the concentration of sol and the amount of dripping. Further, the coating film may be formed by immersing glass fibers in a phosphosilicate sol, and then lifting and drying and heat treatment. In this method, the amount of coating can be controlled by the sol concentration and the glass fiber pulling speed.
[0050]
The amount of coating may be controlled by the amount of sol impregnated into the glass fiber, or may be controlled by repeating step (ii) a plurality of times.
[0051]
The sol is preferably dried at a temperature of 20 ° C to 70 ° C. The heat treatment after drying is preferably performed at a temperature of 100 ° C. or higher, and may be performed, for example, in the range of 100 ° C. to 350 ° C.
[0052]
In addition to the compound (A), the material of the phosphosilicate sol further includes a compound in which some of the substituents of the formula (I) are other substituents. By adding a compound in which a part (for example, one) of the four substituents of formula (I) is an organic group, a phosphosilicate gel film containing an organic component can be formed. In this case, the starting material contains at least one compound represented by the following formula (II) in addition to the compound (A).
Si (OR2)sX2 tZ4-s-t... (II)
[In formula (II), R2Represents an alkyl group, X2Represents a halogen atom, and Z represents an organic group other than an alkoxy group and a halogen atom. 0 ≦ s ≦ 3, 0 ≦ t ≦ 3, and 1 ≦ s + t ≦ 3. ]
[0053]
R2And X2For each, the alkyl group or halogen atom described for R and X in formula (I) can be applied. Examples of the organic group Z include organic groups including an epoxy group, an amino group, an acrylic group, and the like. Specifically, a γ-glycidoxypropyl group can be used.
[0054]
A phosphosilicate gel containing an organic component by hydrolytic condensation of compound (A) and at least one compound represented by chemical formula (II) in a solution in which a compound containing a phosphate structure is dissolved Can be formed.
[0055]
However, the proton conductivity of a phosphosilicate gel that does not substantially contain an organic component (such as an alkyl chain) is about 10 times that of a phosphosilicate gel that contains an organic component. Therefore, in terms of conductivity, it is preferable to prepare a phosphosilicate sol substantially free of organic components using the compound of formula (I) and phosphoric acid. On the other hand, a phosphosilicate gel film containing an organic component has a high toughness as compared with a phosphosilicate gel containing only an inorganic component, and thus is preferable in that a reinforcing material having higher tensile strength can be obtained.
[0056]
The starting material of the phosphosilicate gel may contain other metal alkoxides such as alkoxyaluminum. However, the amount (molar amount) of the other metal alkoxide is smaller than the total amount (molar amount) of the compound represented by the chemical formula (I) and the compound represented by the chemical formula (II).
[0057]
<Method for producing electrolyte membrane>
When the reinforcing material is a glass fiber sheet, an electrolyte membrane can be obtained by disposing an electrolyte in the gap of the glass fiber sheet. For example, a glass fiber sheet may be impregnated with an electrolyte solution, dispersion or sol and then dried. In addition, you may heat-process as needed after drying.
[0058]
When the reinforcing material is a glass fiber sheet and the electrolyte is a polymer electrolyte, for example, the glass fiber sheet may be dipped in a polymer electrolyte solution or dispersion and then dried. For example, first, a dispersion of a fluorine-based polymer electrolyte (polymer electrolyte) is prepared, and a glass fiber sheet is impregnated with a solution obtained by diluting the dispersion with isopropyl alcohol. Then, an electrolyte membrane is obtained by drying and heat-treating the glass fiber sheet impregnated with the electrolyte solution.
[0059]
When the reinforcing material is not a glass fiber sheet but an aggregate of single fibers, an electrolyte membrane reinforced with single fibers is obtained by mixing an electrolyte solution, dispersion or sol with a plurality of single fibers and then drying. be able to. At this time, you may heat-process after drying as needed. For example, an electrolyte membrane can be obtained by mixing a solution or dispersion containing a polymer electrolyte and a plurality of single fibers, and then extending the mixture into a film and drying (heat treatment if necessary).
【Example】
[0060]
EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to a following example. In the following examples, glass fibers having the C glass composition shown in Table 4 were used, but other glass fibers described above may be used.
[0061]
[Table 4]
[Reference Example 1]
Short glass fibers having a C glass composition shown in Table 4, an average diameter of 0.7 μm, and an average length of about 3 mm were prepared. This glass fiber was put into a pulper for unraveling the fiber, and sufficiently dissociated and dispersed in an aqueous solution adjusted to pH 2.5 with sulfuric acid. In this way, a glass fiber dispersion was produced.
[0063]
From this glass fiber dispersion, a glass fiber nonwoven fabric (1) was prepared using a wet papermaking machine. The nonwoven fabric (1) has a thickness of 90 μm and a basis weight of 14 g / m.2Met. The porosity of the nonwoven fabric (1) was about 95% by volume.
[0064]
Next, a phosphosilicate gel film was formed on the glass fiber of the nonwoven fabric (1) by the following method. First, tetraethoxysilane, orthophosphoric acid, ethanol, and pure water were mixed at a molar ratio of approximately 1: 1: 5: 3 and stirred for 2 hours to obtain a phosphosilicate sol. An appropriate amount of this sol was poured into a polyolefin tray, and the glass fiber nonwoven fabric (1) was immersed in the sol. Thereafter, the nonwoven fabric was pulled up from the sol and dried and heat-treated. Thus, the glass fiber nonwoven fabric (2) in which the film of the phosphosilicate gel was formed was obtained.
[0065]
The volume of the phosphosilicate gel coating was about 5% of the glass fiber volume. Moreover, the porosity of the glass fiber nonwoven fabric (2) was about 94.8% by volume.
[0066]
Next, the proton conductive membrane was produced using the nonwoven fabric (2). First, a non-woven fabric (2) was impregnated with a solution obtained by diluting a dispersion of a fluorine-based polymer electrolyte (Nafion DE2020: manufactured by DuPont) with isopropyl alcohol, and air-dried for 12 hours or more. Then, after heat-processing at 120 degreeC for 1 hour, it pressed at 120 degreeC and 10 Mpa with the hot press apparatus. In this way, a proton conductive membrane was obtained. The concentration of the electrolyte dispersion and the amount of impregnation were adjusted so that the thickness of the film after hot pressing was 80 μm.
[0067]
[Reference Examples 2 to 4]
A glass fiber nonwoven fabric (2) on which a coating film was formed was formed in the same manner as in Reference Example 1 except that the volume of the phosphosilicate gel coating film formed on the glass fiber was changed. The volume of the phosphosilicate gel film was about 10% in Reference Example 2, about 40% in Reference Example 3, and about 60% in Reference Example 4 with respect to the volume of the glass fiber.
[0068]
The volume of the coating was controlled by changing the amount of phosphosilicate sol impregnated into the glass fiber nonwoven fabric (1).
[0069]
The porosity of the formed nonwoven fabric (2) was about 94.5% in Reference Example 2, about 93% in Reference Example 3, and about 92% in Reference Example 4. Using these nonwoven fabrics (2), a proton conductive membrane was formed in the same procedure as in Reference Example 1.
[0070]
[Example 5]
A film of a phosphosilicate gel containing an organic component was formed on the glass fiber of the glass fiber nonwoven fabric (1) described in Reference Example 1 by the following method. First, tetraethoxysilane, γ-glycidoxypropyltrimethoxysilane, orthophosphoric acid, ethanol, and pure water are mixed at a molar ratio of approximately 0.25: 0.75: 1: 5: 3. The mixture was stirred for a time to obtain a phosphosilicate sol containing an organic component. An appropriate amount of this sol was poured into a polyolefin tray, and the glass fiber nonwoven fabric (1) was immersed in the sol. Then, the sol was dried at 20 to 70 ° C. while the nonwoven fabric (1) was put in the tray, and then transferred from the tray onto a smooth glass plate and heat treated at 120 to 200 ° C. Thus, the glass fiber nonwoven fabric (2) in which the film of the phosphosilicate type gel containing an organic component was formed was obtained.
[0071]
The volume of the phosphosilicate gel coating was about 5% of the glass fiber volume. Moreover, the porosity of the glass fiber nonwoven fabric (2) was about 94.8% by volume. Using these nonwoven fabrics (2), a proton conductive membrane was formed in the same procedure as in Reference Example 1.
[0072]
[Examples 6 to 9]
A glass fiber nonwoven fabric (2) on which a coating of a phosphosilicate gel containing an organic component was formed was formed in the same manner as in Example 5 except that the volume of the coating formed on the glass fiber was changed. . The volume of the coating of the phosphosilicate gel containing the organic component is about 10% in Example 6, about 40% in Example 7, about 60% in Example 8, and about 9% in Example 9. About 200%.
[0073]
The volume of the coating was changed by adjusting the volume of the sol.
[0074]
The porosity of the obtained nonwoven fabric (2) was about 94.5% in Example 6, about 93% in Example 7, about 92% in Example 8, and about 85% in Example 9. Using these nonwoven fabrics (2), a proton conductive membrane was formed in the same procedure as in Reference Example 1.
[0075]
[Example 10]
Short glass fibers having a C glass composition shown in Table 4, an average diameter of 0.7 μm, and an average length of about 3 mm were prepared. This glass fiber was put into a pulper for unraveling the fiber, and sufficiently dissociated and dispersed in an aqueous solution adjusted to pH 2.5 with sulfuric acid. In this way, a glass fiber dispersion was produced.
[0076]
A glass fiber non-woven fabric (1) was produced from this glass fiber dispersion by forming a glass fiber sheet using a wet papermaking machine and pressing it before drying. The glass fiber nonwoven fabric (1) has a thickness of 90 μm and a basis weight of 30 g / m.2Met. The porosity of this glass fiber nonwoven fabric was about 87% by volume.
[0077]
Next, a phosphosilicate film containing an organic component was formed on the glass fiber of the glass fiber nonwoven fabric (1) by the following method. First, tetraethoxysilane, orthophosphoric acid, ethanol, and pure water were mixed at a molar ratio of approximately 1: 1: 5: 3 and stirred for 2 hours to obtain a phosphosilicate sol. An appropriate amount of this sol was poured into a polyolefin tray, and the glass fiber nonwoven fabric (1) was impregnated in the sol. Thereafter, the nonwoven fabric was pulled up from the sol and dried and heat-treated. Thus, the glass fiber nonwoven fabric (2) in which the film of the phosphosilicate type gel containing an organic component was formed was obtained. The volume of the phosphosilicate gel coating was about 5% of the glass fiber volume. Moreover, the porosity of the glass fiber nonwoven fabric (2) was about 86% by volume. Using this nonwoven fabric (2), a proton conductive membrane was formed in the same procedure as in Reference Example 1.
[0078]
[Comparative Example 1]
The electrolyte dispersion used in Reference Example 1 was placed in a glass petri dish with good flatness at the bottom, dried naturally for 12 hours or more, and then heat treated at 120 ° C. for 1 hour to form a film. This membrane electrolyte was pressed at 120 ° C. and 10 MPa by a hot press apparatus to obtain a proton conductive membrane. The concentration of the electrolyte dispersion was the same as in Reference Example 1, and the liquid volume was adjusted so that the thickness of the film after hot pressing was 80 μm.
[0079]
[Comparative Example 2]
A proton conductive membrane was formed in the same manner as in Reference Example 1 except that the glass fiber nonwoven fabric (1) described in Reference Example 1 was used as a reinforcing material as it was without forming a film. The concentration of the electrolyte dispersion and the amount of impregnation were adjusted so that the thickness of the film after hot pressing was 80 μm.
[0080]
[Evaluation of reinforcing material and proton conductive membrane]
The following measurements were performed on the reinforcing materials and proton conductive membranes prepared in Reference Examples 1 to 4 and Examples 5 to 10 and Comparative Examples 1 and 2 described above. In addition, the reinforcing material of the reference examples 1-4 and Examples 5-10 is a glass fiber nonwoven fabric (2) provided with a film, and the reinforcing material of the comparative example 2 is a glass fiber nonwoven fabric (1) without a film. .
[0081]
[Reinforcement thickness]
With the reinforcing material pressed at a pressure of about 20 kPa, the thickness of the reinforcing material was measured using a thickness gauge.
[0082]
[Proton conductive membrane thickness]
Measurement was performed using a micrometer.
[0083]
[Measurement of tensile strength of reinforcing material and proton conductive membrane]
Each of the reinforcing material and the electrolyte membrane was cut into a width of 20 mm and a length of 80 mm to prepare a test piece. The test piece was chucked at a chuck interval of 30 mm and pulled at a speed of 10 mm / min, and the load (N) at break was measured. The measured value was divided by the actual measured values of the sample thickness and width to calculate the tensile strength (MPa).
[0084]
[Proton conductivity]
Using an impedance analyzer, proton conductivity (S / m) in the thickness direction of the proton conductive membrane was measured.
[0085]
The above measurement results are shown in Table 5.
[0086]
[Table 5]
As is clear from Table 5, the reinforcing materials of Reference Examples 1 to 4 and Examples 5 to 10 had higher tensile strength than the reinforcing material of Comparative Example 2. In addition, the proton conductive membranes of Reference Examples 1 to 4 and Examples 5 to 10 had the same proton conductivity and high tensile strength as compared with the proton conductive membranes of the comparative examples.
[Industrial applicability]
[0088]
The present invention can be applied to a reinforcing material for an electrolyte membrane used in a fuel cell, and an electrolyte membrane and a fuel cell using the same. The present invention can also be applied to a method for manufacturing an electrolyte membrane reinforcing material.
Claims (15)
前記被膜が、γ−グリシドキシプロピル基を含むホスホシリケート系ゲルである電解質膜補強材。An electrolyte membrane reinforcing material comprising glass fibers and a phosphosilicate gel film formed on the glass fibers,
An electrolyte membrane reinforcing material, wherein the coating is a phosphosilicate gel containing a γ-glycidoxypropyl group .
Ｓｉ（ＯＲ）Si (OR) mm ＸX 4-m4-m ・・・（Ｉ）... (I)
［式（Ｉ）において、Ｒはアルキル基を示し、Ｘはハロゲン原子を示し、ｍは１以上４以下の整数を示す。］[In the formula (I), R represents an alkyl group, X represents a halogen atom, and m represents an integer of 1 to 4. ]
Ｓｉ（ＯＲSi (OR 22 ）) ss ＸX 22 tt ＺZ 4-s-t4-s-t ・・・（II）... (II)
［式（II）において、Ｒ[In formula (II), R 22 はアルキル基を示し、ＸRepresents an alkyl group, X 22 はハロゲン原子を示し、Ｚは、γ−グリシドキシプロピル基を示す。０≦ｓ≦３、０≦ｔ≦３、１≦ｓ＋ｔ≦３である。］Represents a halogen atom, and Z represents a γ-glycidoxypropyl group. 0 ≦ s ≦ 3, 0 ≦ t ≦ 3, and 1 ≦ s + t ≦ 3. ]
前記補強材が、ガラス繊維と前記ガラス繊維上に形成されたホスホシリケート系ゲルの被膜とを含み、
前記被膜が、γ−グリシドキシプロピル基を含むホスホシリケート系ゲルである電解質膜。An electrolyte membrane comprising a reinforcing material and an electrolyte reinforced with the reinforcing material,
The reinforcing material includes glass fiber and a phosphosilicate gel film formed on the glass fiber,
An electrolyte membrane, wherein the coating is a phosphosilicate gel containing a γ-glycidoxypropyl group .
Ｓｉ（ＯＲ）Si (OR) mm ＸX 4-m4-m ・・・（Ｉ）... (I)
［式（Ｉ）において、Ｒはアルキル基を示し、Ｘはハロゲン原子を示し、ｍは１以上４以下の整数を示す。］[In the formula (I), R represents an alkyl group, X represents a halogen atom, and m represents an integer of 1 to 4. ]
Ｓｉ（ＯＲSi (OR 22 ）) ss ＸX 22 tt ＺZ 4-s-t4-s-t ・・・（II）... (II)
［式（II）において、Ｒ[In formula (II), R 22 はアルキル基を示し、ＸRepresents an alkyl group, X 22 はハロゲン原子を示し、Ｚは、γ−グリシドキシプロピル基を示す。０≦ｓ≦３、０≦ｔ≦３、１≦ｓ＋ｔ≦３である。］Represents a halogen atom, and Z represents a γ-glycidoxypropyl group. 0 ≦ s ≦ 3, 0 ≦ t ≦ 3, and 1 ≦ s + t ≦ 3. ]
（ii）ガラス繊維の表面に前記ホスホシリケート系ゾルを塗布したのち、熱処理することによって前記ガラス繊維の表面にホスホシリケート系ゲルの被膜を形成する工程とを含み、
前記出発材料が、以下の式（II）で表される少なくとも１種類の化合物を含む電解質膜補強材の製造方法。
Ｓｉ（ＯＲ）mＸ4-m・・・（Ｉ）
［式（Ｉ）において、Ｒはアルキル基を示し、Ｘはハロゲン原子を示し、ｍは１以上４以下の整数を示す。］
Ｓｉ（ＯＲ2）sＸ2 tＺ4-s-t・・・（II）
［式（II）において、Ｒ2はアルキル基を示し、Ｘ2はハロゲン原子を示し、Ｚは、アルコキシ基およびハロゲン原子以外の有機基を示す。０≦ｓ≦３、０≦ｔ≦３、１≦ｓ＋ｔ≦３である。］」(I) preparing a phosphosilicate sol from a starting material containing at least one compound represented by the following formula (I) and a compound containing a phosphate structure;
(Ii) forming a phosphosilicate gel film on the surface of the glass fiber by applying heat treatment after applying the phosphosilicate sol to the surface of the glass fiber;
The manufacturing method of the electrolyte membrane reinforcing material in which the said starting material contains the at least 1 sort (s) of compound represented by the following formula | equation (II).
Si (OR) m X 4-m (I)
[In the formula (I), R represents an alkyl group, X represents a halogen atom, and m represents an integer of 1 to 4. ]
Si (OR 2 ) s X 2 t Z 4-st (II)
[In the formula (II), R 2 represents an alkyl group, X 2 represents a halogen atom, and Z represents an organic group other than an alkoxy group and a halogen atom. 0 ≦ s ≦ 3, 0 ≦ t ≦ 3, and 1 ≦ s + t ≦ 3. ] "
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| PCT/JP2006/300204 WO2006075611A1 (en) | 2005-01-12 | 2006-01-11 | Electrolyte membrane-reinforcing material, electrolyte membrane using same, fuel cell, and method for producing electrolyte membrane-reinforcing material |
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| EP2109173B1 (en) * | 2008-04-07 | 2013-05-08 | Topsøe Fuel Cell A/S | Solid oxide fuel cell stack, process for the preparation thereof and use of an E-glass therein |
| JP2016058152A (en) * | 2014-09-05 | 2016-04-21 | 日本バイリーン株式会社 | Method for manufacturing resin reinforced material, resin reinforced material, polymer electrolyte reinforced membrane, membrane-electrode assembly, and solid polymer fuel cell |
| US11760901B2 (en) * | 2018-07-19 | 2023-09-19 | Illinois Tool Works Inc. | Film forming formulation and composition thereof |
| CN114976258B (en) * | 2022-05-17 | 2024-10-01 | 哈尔滨工业大学 | Composite polymer electrolyte conducive to uniform lithium deposition and preparation method and application thereof |
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| JP2003100316A (en) * | 2001-09-21 | 2003-04-04 | Sekisui Chem Co Ltd | Proton conductive membrane and its manufacturing method |
| JP2003317748A (en) * | 2002-04-23 | 2003-11-07 | Araco Corp | Solid polyelectrolyte film |
| JP2004186120A (en) * | 2002-12-06 | 2004-07-02 | Toyota Motor Corp | Solid polymer electrolyte, solid polymer electrolyte membrane, and fuel cell |
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| JP4956866B2 (en) * | 2001-04-26 | 2012-06-20 | Ｔｄｋ株式会社 | Silica gel electrolyte membrane, method for producing the same, and fuel cell |
| US7214756B2 (en) * | 2001-10-30 | 2007-05-08 | Sekisui Chemical Co., Ltd. | Proton conducting membrane, process for its production, and fuel cells made by using the same |
| JP2003178773A (en) * | 2001-12-11 | 2003-06-27 | Sanyo Electric Co Ltd | Fuel-cell unit |
| JP2004047450A (en) * | 2002-05-20 | 2004-02-12 | Nippon Sheet Glass Co Ltd | Reinforcing material for proton conductive film, proton conductive film using same and fuel cell using same |
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| JP2003100316A (en) * | 2001-09-21 | 2003-04-04 | Sekisui Chem Co Ltd | Proton conductive membrane and its manufacturing method |
| JP2003317748A (en) * | 2002-04-23 | 2003-11-07 | Araco Corp | Solid polyelectrolyte film |
| JP2004186120A (en) * | 2002-12-06 | 2004-07-02 | Toyota Motor Corp | Solid polymer electrolyte, solid polymer electrolyte membrane, and fuel cell |
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| KR102015028B1 (en) | 2016-02-18 | 2019-08-27 | 주식회사 엘지화학 | Core-shell particle, polymer electrolyte membrane comprising the same, fuel cell or electrochemical cell comprising the polymer electrolyte membrane and method of manufacturing the core-shell particle |
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