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

Abstract

Summary 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°C, whereas the casting membranes do not. Enhanced proton conductivity of 158 mS cm−2 at 80°C was observed in the developed membrane; the conductivity is maintained up to 130°C. The operation of PEMFC with the electrically treated membrane at 120°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.

Electric Field-Assisted Filling of Sulfonated Polymers in ePTFE Backing Material for Fuel Cell

“…According to the literature [ 9 , 10 , 11 , 17 , 25 , 26 , 27 ], the ion channel is much more in order than that of the original membrane due to the process of electron alignment, and the ion channel in the membrane becomes shorter, which leads to the effective improvement of proton conductivity of the membrane. Therefore, in theory, the conductivity of the membrane should increase with the electric field.…”

“…Ref. [ 25 ] Poly(arylene ether)s synthesized using a multiphenylated difluoro monomer with a trifluoromethylphenyl side chain and three types of multiphenylated bisphenol monomer, which become partially fluorinated sulfonated poly(arylene ether)s with highly efficient proton transport [ 26 ].…”

“…This membrane was soaked in the filtered sulfonated polymer solution. With the membrane in it, the solution was placed on a piece of ITO conductive glass with the cathode electrode fixed on it [ 25 ]. As Figure 2 , the anode electrode was fixed on the membrane coating bar wrapped on an iron piece.…”

“…The SA8 polymer with good overall performance was selected for this study. The membrane-forming technique proposed in the literature [ 25 ] was introduced, and an SA8 solution was used to fill the ePTFE pores, while a vertical electric field was applied externally to generate an SA8 membrane. The ePTFE is a porous membrane created by expanding and stretching polytetrafluoroethylene.…”

Improved performance of nafion membranes by blending ultra-high molecular weight polyvinylidene fluoride

“…Nafion is a commercial PEM which is widely used in PEMFCs due to superior proton conductivity under high humidity condition, satisfactory mechanical features and excellent chemical stability in severe environment. However, with the urgent demand for high power density of fuel cell, the ultra-thin PEM (~15μm) based Nafion severely restrict the further development of PEMFCs due to undesirable gas permeation and poor mechanical strength [9,10]. Incorporation of organic or inorganic nano materials is one of the promising methods to optimize Nafion membrane for operation.…”