High-temperature operation of PEMFC using pore-filling PTFE/Nafion composite membrane treated with electric field

Abstract

A pore-filling polytetrafluoroethylene (PTFE)/Nafion composite membrane was developed for the high-temperature operation of proton-exchange membrane fuel cell (PEMFC). Porous PTFE substrate was filled with Nafion solution and cast under an electric field to align ion channel in the through-plane direction, in which thermal stability and proton conductivity were improved simultaneously. The membranes keep their ion-exchange ability at high temperatures above 110 degrees C, whereas the casting membranes do not. Enhanced proton conductivity of 158 mS cm(-2) at 80 degrees C was observed in the developed membrane; the conductivity is maintained up to 130 degrees C. The operation of PEMFC with the electrically treated membrane at 120 degrees C showed a performance improvement of 40% compare to the non-treated pore-filling membrane as indicated by enhanced proton conductivity. In this study, we demonstrate that the electrical alignment of the ion channel in the through-plane direction improves the proton conductivity and fuel cell performance at a high temperature for a pore-filling composite membrane.