A high performance polyamide-based proton exchange membrane fabricated via construction of hierarchical proton conductive channels

A concept of hierarchical proton conductive channel (HPCC) capable of simultaneously boosting proton conductivity and fuel-permeation resistivity is proposed and the HPCC is optimized to improve the performance of the hyperbranched polyamide proton exchange membrane. The HPCC built in-situ in the membrane can be tuned by simply changing two amine groups from the meta-position to the para-position in the monomers. We demonstrate that the small structural difference between the two monomers may result in remarkable differences in mechanical and electrochemical properties upon polymerization, which enable significantly improved performance of direct methanol fuel cells. (C) 2015 Elsevier B.V. All rights reserved.