Abstract: A Highly Conductive Quaternary-Phosphonium Functionalized Membrane for High-Performance Hydroxide Exchange Membrane Fuel Cells (2009 Annual Meeting)

Monday, November 9, 2009: 3:35 PM

Washington B (Gaylord Opryland Hotel)

Shuang Gu, Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA

Rui Cai, Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA

Ting Luo, Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA

Kurt Jensen, Department of Chemical & Environmental Engineering, University of California, Riverside, Riverside, CA

Yushan Yan, Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA

As a novel fuel cell technology, the hydroxide (OH-) exchange membrane fuel cells (HEMFCs) have been demonstrated to have the potential to solve the proton exchange membrane fuel cells' (PEMFC's) crippling dependence on precious metals as electrode [1]. In addition, HEMFCs can completely avoid the electrolyte leakage and potentially eliminate the metal (bi)carbonate formation problems of the traditional liquid alkaline fuel cells (AFCs) [2].

As one of the most crucial parts of HEMFCs, the hydroxide exchange membrane (HEM) usually directly decided the performance of HEMFCs through its hydroxide-conductivity and membrane-thickness. Current HEMs are based on the quaternary-ammonium-hydroxide (QAOH) functional groups, and have low performance due to its hydroxide conductivity. By switching from the QAOH to the quaternary-phosphonium-hydroxide (QPOH), the HEM may have the potential to solve the low hydroxide-conductivity problem and thus improve the HEMFC performance drastically.

In this work, by optimizing the degree of chloromethylation and the preparation-procedure of membrane, we synthesized and prepared a quaternary-phosphonium functionalized hydroxide exchange membrane (TPQPOH152) with typical thickness of 50-100 μm. TPQPOH showed a 45 mS/cm (20 oC) of hydroxide-conductivity that is substantially higher than those of the commercial and currently experimental QAOH functionalized membranes. In addition, the HEMFC single cell with a 50 μm TPQPOH152 as HEM, at 70 oC, exhibited substantially high peak power density of 258 mW/cm2 and significantly low internal resistance of 0.21 Ωcm2. The high hydroxide-conductivity and high-performance of HEMFC indicate that the quaternary-phosphonium functionalized TPQPOH152 HEM is highly promising for use in HEMFC.

References

[1] S. Gu, R. Cai, T. Luo, Z. Chen, M. Sun, Y. Liu, G. He, Y. Yan, Angewandte Chemie International Edition 2009, in press.

[2] J. R. Varcoe, R. C. T. Slade, Fuel Cells 2005, 5, 187.

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See more of this Session: Fuel Cell Technology III
See more of this Group/Topical: Fuels and Petrochemicals Division