A new structured composite membrane for fuel cell applications

A new proton conducting membrane was prepared by confining sub-nanoliter volumes of perfluorosulfonic acid (PFSA) polymer within rigid pores cladded with zeolite layers. Tests showed membrane-electrode assembly (MEA) made of confined Nafion PFSA-HZSM-5/Sil-1 structured composite membrane delivered an order of magnitude higher MPD (maximum power density) compared to a standard Nafion 117 MEA in a hydrogen PEMFC at high temperature operation under dry feed conditions. Similarly, 900% higher MPD was obtained from direct methanol fuel cell (DMFC) made of the new membrane. The zeolites are believed to play an active role in the water and methanol managements through adsorption and transport, and the confinement of the PFSA within zeolite environment changes its microstructure resulting in the improved thermal stability.

Zeolites were employed in fuel cell as structured composite membrane to achieve enhanced fuel cell performance compared to traditional Nafion MEA.Figure optionsDownload high-quality image (151 K)Download as PowerPoint slideHighlights
► Self-humidifying membrane based on subnanoliter confinement of Nafion within zeolite sleeves.
► Zeolite retains and regulates water within Nafion slugs for high temperature, dry fuel cell operation.
► Chain restructuring in confined Nafion yields better thermal properties and higher proton conduction.
► Reduced fuel crossover in DMFC with enhanced performance under passive methanol feed.