Nafion/PTFE Composite Membranes for a High Temperature PEM Fuel Cell Application

The main bottlenecks for the application of polymer electrolyte fuel cells in electric vehicles are the high cost and the inferior performance of Nafion at high temperatures above 80 °C. In this work, composite membranes made by infiltrating Nafion in various PTFE fibrous substrates were prepared, characterized, and assessed for a single fuel cell performance. Prepared by a simple dip-coating method, the composite membrane exhibited satisfactory mechanical strength and thermal stability with the incorporation of a PTFE backbone, which can suppress the swelling of the Nafion component. The durability of the composite membranes in terms of through-plane conductivity after boiling at 120 °C was comparable to that of Nafion117. Moreover, the Nafion/PTFE membrane was able to achieve higher through-plane conductivity than Nafion117 at higher temperatures of 100 °C, indicating potential application in high temperature condition.