The Dow Chemical Company

Timothy J Rehg

Alan J Cisar

Michael E Mills

William P Carl

Chieh-Chun Chau

George J Quarderer, Jr

Robert D Mussell

Yoshihiko Teramoto

Keith R Plowman

Myrna Serrano

Timothy L Faley

Masaru Nakagawa

Ravi B Shanker

Charles S Eastland

Larry W Davis

Described is a membrane electrode assembly having an ion exchange membrane, and at least two active layers positioned on the same side of the membrane; wherein the active layers containing catalytically-active particles and an ionomer; the average equivalent weights of the ionomers in the layers differ by at least 50; and the active layer positioned closest to the membrane contains the ionomer with the lower average equivalent weight. This membrane electrode assembly, when utilized in a fuel cell, provides a relatively high voltage at a given current density and gas flow rate.

Active layer for membrane electrode assembly

A bilayer or trilayer composite ion exchange membrane suitable for use in a fuel cell. The composite membrane has a high equivalent weight thick layer in order to provide sufficient strength and low equivalent weight surface layers for improved electrical performance in a fuel cell. In use, the composite membrane is provided with electrode surface layers. The composite membrane can be composed of a sulfonic fluoropolymer in both core and surface layers.

Composite fuel cell membranes

Polybenzazole polymer dopes are spun into fibers at high speed by passing through a spinneret with proper selection of hole geometry, followed by spin-drawing to a spin-draw ratio of at least 20, washing, taking up and drying. The take up speed is at least about 150 meters per minute, and the fibers are spun in at least 10 km lengths without a break.

Method for spinning a polybenzazole fiber

Growing community of inventors

Midland, MI, United States of America

Timothy J Rehg