Enhanced performance of sulfonated poly (ether ether ketone) membranes by blending fully aromatic polyamide for practical application in direct methanol fuel cells (DMFCs)

The high dimensional swelling has been considered as one of the most important issues for obstructing sulfonated poly (ether ether ketone) (SPEEK) membrane with high IEC value as an excellent performance proton exchange membrane (PEM) for direct methanol fuel cell (DMFC) application. Here, we present a facile way to overcome the issue via blending the fully aromatic polyamide (fa-PA) into SPEEK membrane. The Influence of the fa-PA on the key properties of the fabricated fa-PA/SPEEK composite membranes (fa-PASPs) was systematically investigated. As the promising dimensional stability of the fa-PA, the fa-PASPs display excellent dimensional stability both in water and methanol aqueous solution. In addition, the fa-PASPs exhibit uniform and smooth morphology due to the same fully aromatic polyamide backbones as SPEEK and strong hydrogen bonding interactions between fa-PA and SPEEK with significantly reduced methanol crossover. The remarkable cell performance at high methanol concentration up to neat methanol was significantly obtained, suggesting that the prepared fa-PASPs are suitable for using as PEMs in direct methanol fuel cells application.