Thermal stability of proton conducting acid doped polybenzimidazole in simulated fuel cell environments

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Journal of the Electrochemical Society

DOI:https://doi.org/10.1149/1.1836621· OSTI ID:251054

Samms, S R; Wasmus, S; Savinell, R F ^[1]

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1. Case Western Reserve Univ., Cleveland, OH (United States)

Recently, polybenzimidazole membrane doped with phosphoric acid (PBI) was found to have promising properties for use as a polymer electrolyte in a high temperature (ca. 150 to 200 C) proton exchange membrane direct methanol fuel cell. However, operation at 200 C in strongly reducing and oxidizing environments introduces concerns of the thermal stability of the polymer electrolyte. To simulate the conditions in a high temperature fuel cell, PBI samples were loaded with fuel cell grade platinum black, doped with ca. 480 mole percent phosphoric acid (i.e., 4.8 H{sub 3}PO{sub 4} molecules per PBI repeat unit) and heated under atmospheres of either nitrogen, 5% hydrogen, or air in a thermal gravimetric analyzer. The products of decomposition were taken directly into a mass spectrometer for identification. In all cases weight loss below 400 C was found to be due to loss of water. Judging from the results of these tests, the thermal stability of PBI is more than adequate for use as a polymer electrolyte in a high temperature fuel cell.

• Sponsoring Organization: USDOE
• OSTI ID: 251054
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 4 Vol. 143; ISSN JESOAN; ISSN 0013-4651
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
ALCOHOL FUEL CELLS
BENZIMIDAZOLES
DEHYDRATION
ORGANIC POLYMERS
SOLID ELECTROLYTE FUEL CELLS
SOLID ELECTROLYTES
STABILITY
THERMAL TESTING