Cross-Linked Anion Exchange Membranes for AEMFC

Abstract

Anion-exchange membranes (AEMs) have attracted great interest for their operation in alkaline platinum-free fuel cells .However the use of AEMs in a wide range of devices has been limited due to various challenges. Two major obstacles are the membranes' low conductivity and poor stability in the highly alkaline environment required for fuel cells that necessitates generation of hydroxide anions and transport through the solid polymer membrane.The effect of cross-linker and its apparent impact on AEM properties will be the focus of this study. Two different cross-linkers were chosen, one has an amino-ether group and the other, has a trymethylhexadecyl amine group. These two crosslinkers have a fundamental difference, where the amino-ether is more hydrophilic and therefore would improve membrane's conductivity and may prevent membrane’s drying out. The properties and stability of the membrane with these two cross-linkers were investigated. Conductivity and swelling measurments were examined at various temperatures for both types of samples. Indeed, water uptake and conductivity were found to be higher for the amino-ether crosslinker. However, degradation measurements analyzed by FTIR and XPS, indicated that the membrane cross-linked by amino-ether group degraded faster at high temperature and pH conditions. Thus, the ether linkage in the cross-linker has a negative influence on the thermal and alkaline stability of the membrane.