TY - JOUR
T1 - A flexible all-inorganic fuel cell membrane with conductivity above Nafion, and durable operation at 150 °c
AU - Ansari, Y.
AU - Tucker, T. G.
AU - Huang, W.
AU - Klein, I. S.
AU - Lee, S. Y.
AU - Yarger, Jeffery
AU - Angell, Charles
N1 - Funding Information:
This work has been carried out under the auspices of the DOD- Army research office , under Grant no. W911NF-07-1-0423 for the synthesis and fuel cell work, and to W911NF-11-1-0263 for the structural analysis. We appreciate much valuable advice given by Don Gervasio during the development of our fuel cell interests. He also provided the design of the fuel cell of Fig. 3 which was used in previous joint publications [14,52] .
Publisher Copyright:
© 2015 Elsevier B.V.All rights reserved.
PY - 2016/1/30
Y1 - 2016/1/30
N2 - The search for fuel cell membranes has focused on carbon backbone polymers, among which Nafion seems to best survive the most severe of the degradation mechanisms - attack by peroxide radicals. Less attention has been given to inorganic membranes because of their generally inflexible nature and lower conductivity, though some SiO2-Nafion composites have shown improved properties. Nafion dominates, despite needing hydration, which then restricts operation to below 100 °C (so CO poisoning problems persist). Described herein is a low cost, flexible, and all-inorganic fiberglass reinforced gel membrane with conductivity exceeding that of Nafion at any temperature above 60 °C. Using Teflon fuel cells, maximum currents > 1 Acm-2 and OCV of 1.03 V at 150 °C are demonstrated. No detectable loss of cell potential was observed over 24 h during 50 mAcm-2 constant current operation at 120 °C while, at 150 °C and maximum power, the degradation rate is intermediate among other high conductivity H3PO4-PBI type membranes. The structure of the membrane is deduced, mainly from 29Si solid state-NMR. The -115 ppm resonance, which is extreme for Q4 Si(O) structures, identifies a zeolite-like SiO2 network, which is "floppy". 31P and 1H NMR establish nano-permeating H3PO4 as the source of the exceptional conductivity.
AB - The search for fuel cell membranes has focused on carbon backbone polymers, among which Nafion seems to best survive the most severe of the degradation mechanisms - attack by peroxide radicals. Less attention has been given to inorganic membranes because of their generally inflexible nature and lower conductivity, though some SiO2-Nafion composites have shown improved properties. Nafion dominates, despite needing hydration, which then restricts operation to below 100 °C (so CO poisoning problems persist). Described herein is a low cost, flexible, and all-inorganic fiberglass reinforced gel membrane with conductivity exceeding that of Nafion at any temperature above 60 °C. Using Teflon fuel cells, maximum currents > 1 Acm-2 and OCV of 1.03 V at 150 °C are demonstrated. No detectable loss of cell potential was observed over 24 h during 50 mAcm-2 constant current operation at 120 °C while, at 150 °C and maximum power, the degradation rate is intermediate among other high conductivity H3PO4-PBI type membranes. The structure of the membrane is deduced, mainly from 29Si solid state-NMR. The -115 ppm resonance, which is extreme for Q4 Si(O) structures, identifies a zeolite-like SiO2 network, which is "floppy". 31P and 1H NMR establish nano-permeating H3PO4 as the source of the exceptional conductivity.
KW - 150 °C fuel cell
KW - Conductivity above Nafion
KW - Inorganic fuel cell membrane
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U2 - 10.1016/j.jpowsour.2015.10.034
DO - 10.1016/j.jpowsour.2015.10.034
M3 - Article
AN - SCOPUS:84946606395
SN - 0378-7753
VL - 303
SP - 142
EP - 149
JO - Journal of Power Sources
JF - Journal of Power Sources
ER -