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Title: Grafted functional groups on expanded tetrafluoroethylene (ePTFE) support for fuel cell and water transport membranes

Abstract

A method for forming a modified solid polymer includes a step of contacting a solid fluorinated polymer with a sodium sodium-naphthalenide solution to form a treated fluorinated solid polymer. The treated fluorinated solid polymer is contacted with carbon dioxide, sulfur dioxide, or sulfur trioxide to form a solid grafted fluorinated polymer. Characteristically, the grafted fluorinated polymer includes appended CO.sub.2H or SO.sub.2H or SO.sub.3H groups. The solid grafted fluorinated polymer is advantageously incorporated into a fuel cell as part of the ion-conducting membrane or a water transport membrane in a humidifier.

Inventors:
;
Publication Date:
Research Org.:
GM GLOBAL TECHNOLOGY OPERATIONS LLC, Detroit, MI (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1340532
Patent Number(s):
9,553,327
Application Number:
14/586,132
Assignee:
GM GLOBAL TECHNOLOGY OPERATIONS LLC (Detroit, MI) DOEEE
DOE Contract Number:
EE0000470
Resource Type:
Patent
Resource Relation:
Patent File Date: 2014 Dec 30
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Fuller, Timothy J., and Jiang, Ruichun. Grafted functional groups on expanded tetrafluoroethylene (ePTFE) support for fuel cell and water transport membranes. United States: N. p., 2017. Web.
Fuller, Timothy J., & Jiang, Ruichun. Grafted functional groups on expanded tetrafluoroethylene (ePTFE) support for fuel cell and water transport membranes. United States.
Fuller, Timothy J., and Jiang, Ruichun. Tue . "Grafted functional groups on expanded tetrafluoroethylene (ePTFE) support for fuel cell and water transport membranes". United States. doi:. https://www.osti.gov/servlets/purl/1340532.
@article{osti_1340532,
title = {Grafted functional groups on expanded tetrafluoroethylene (ePTFE) support for fuel cell and water transport membranes},
author = {Fuller, Timothy J. and Jiang, Ruichun},
abstractNote = {A method for forming a modified solid polymer includes a step of contacting a solid fluorinated polymer with a sodium sodium-naphthalenide solution to form a treated fluorinated solid polymer. The treated fluorinated solid polymer is contacted with carbon dioxide, sulfur dioxide, or sulfur trioxide to form a solid grafted fluorinated polymer. Characteristically, the grafted fluorinated polymer includes appended CO.sub.2H or SO.sub.2H or SO.sub.3H groups. The solid grafted fluorinated polymer is advantageously incorporated into a fuel cell as part of the ion-conducting membrane or a water transport membrane in a humidifier.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 24 00:00:00 EST 2017},
month = {Tue Jan 24 00:00:00 EST 2017}
}

Patent:

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  • The moisture content and temperature of hydrogen and oxygen gases is regulated throughout traverse of the gases in a fuel cell incorporating a solid polymer membrane. At least one of the gases traverses a first flow field adjacent the solid polymer membrane, where chemical reactions occur to generate an electrical current. A second flow field is located sequential with the first flow field and incorporates a membrane for effective water transport. A control fluid is then circulated adjacent the second membrane on the face opposite the fuel cell gas wherein moisture is either transported from the control fluid to humidifymore » a fuel gas, e.g., hydrogen, or to the control fluid to prevent excess water buildup in the oxidizer gas, e.g., oxygen. Evaporation of water into the control gas and the control gas temperature act to control the fuel cell gas temperatures throughout the traverse of the fuel cell by the gases.« less
  • The moisture content and temperature of hydrogen and oxygen gases are regulated throughout traverse of the gases in a fuel cell incorporating a solid polymer membrane. At least one of the gases traverses a first flow field adjacent the solid polymer membrane, where chemical reactions occur to generate an electrical current. A second flow field is located sequential with the first flow field and incorporates a membrane for effective water transport. A control fluid is then circulated adjacent the second membrane on the face opposite the fuel cell gas wherein moisture is either transported from the control fluid to humidifymore » a fuel gas, e.g., hydrogen, or to the control fluid to prevent excess water buildup in the oxidizer gas, e.g., oxygen. Evaporation of water into the control gas and the control gas temperature act to control the fuel cell gas temperatures throughout the traverse of the fuel cell by the gases. 6 figs.« less
  • The moisture content and temperature of hydrogen and oxygen gases is regulated throughout traverse of the gases in a fuel cell incorporating a solid polymer membrane. At least one of the gases traverses a first flow field adjacent the solid polymer membrane, where chemical reactions occur to generate an electrical current. A second flow field is located sequential with the first flow field and incorporates a membrane for effective water transport. A control fluid is then circulated adjacent the second membrane on the face opposite the fuel cell gas wherein moisture is either transported from the control fluid to humidifymore » a fuel gas, e.g., hydrogen, or to the control fluid to prevent excess water buildup in the oxidizer gas, e.g., oxygen. Evaporation of water into the control gas and the control gas temperature act to control the fuel cell gas temperatures throughout the traverse of the fuel cell by the gases. 10 figs.« less
  • The authors have demonstrated earlier the useful performance of PSI radiation-grafted membranes in terms of the current-voltage characteristics of 30 cm{sup 2} active area fuel cells containing these membranes and their long-term testing over 6,000 h at 60 C. They report here on testing of PSI radiation-grafted membranes in these fuel cells at 80 C and in short stacks comprised of two or four 100 cm{sup 2} active area cells. The in-situ degradation of membranes has been investigated by characterizing membranes both before testing in fuel cells and post-mortem after testing in fuel cells. Characterization was accomplished by means ofmore » ion-exchange capacity and infrared and Raman spectroscopic measurements. In addition, a rapid screening method for ex-situ testing of the oxidative stability of proton-conducting membranes was developed in this work. Comparison of the initial screening test results concerning the oxidative stability of some perfluorinated, partially-fluorinated, and non-fluorinated membranes compare well qualitatively with the relative stability of these same membranes during their long-term testing in fuel cells.« less
  • Water uptake and transport parameters measured at 30 C for several available perfluorosulfonic acid membranes are compared. The water sorption characteristics, diffusion coefficient of water, electroosmotic drag, and protonic conductivity were determined for Nafion 117, Membrane C, and Dow XUS 13204.10 developmental fuel cell membrane. The diffusion coefficient and conductivity of each of these membranes were determined as functions of membrane water content. Experimental determination of transport parameters, enables one to compare membranes without the skewing effects of extensive features such as membrane thickness which contributes in a nonlinear fashion to performance in polymer electrolyte fuel cells.