Biofunctionalized nanofiber hybrid proton exchange membrane based on acid-base ion-nanochannels with superior proton conductivity

Abstract

Regulating nanophase-separation behavior and constructing ion-nanochannels is of great importance for improving proton transport inside membrane. Herein, a novel strategy is proposed for constructing long-range and consecutive acid–base ion-nanochannels through embedding basic l-Arginine biofunctionalized hydrolyzed polyacrylonitrile nanofibers into acidic sulfonated polysulfone matrix, combing the superiority of the special three-dimensional network structure of nanofibers and the function of basic l-Arginine as proton-conductors. The formed acid–base ion-nanochannels between –SO3H of sulfonated polysulfone and –NH2 of l-Arginine biofunctionalized hydrolyzed polyacrylonitrile nanofibers may offer the abundant hydrogen-bonded networks for proton hopping. The results show nanofiber hybrid proton exchange membranes can achieve 0.216 S/cm (80 °C, 100% relative humidity) proton conductivity and 115.93 mW/cm2 power density for fuel-cell performance. Besides, the preponderance of three-dimensional network structure of nanofibers may considerably facilitate the thermal and dimensional stability as well as restrict methanol crossover for hybrid proton exchange membranes. This approach brings a unique vision for preparing high-performance proton exchange membranes for direct methanol fuel cells.