(147b) A Highly Conductive Quaternary-Phosphonium Functionalized Membrane for High-Performance Hydroxide Exchange Membrane Fuel Cells | AIChE

Other Sites & Tools

Technical Groups

(147b) A Highly Conductive Quaternary-Phosphonium Functionalized Membrane for High-Performance Hydroxide Exchange Membrane Fuel Cells

Authors 

Gu, S. - Presenter, University of California, Riverside
Cai, R. - Presenter, University of California, Riverside
Luo, T. - Presenter, University of California, Riverside
Jensen, K. - Presenter, University of California, Riverside
Yan, Y. - Presenter, University of Delaware


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.

More Conference Links