Hydrocarbon-based composite membranes containing sulfonated Poly(arylene thioether sulfone)-grafted 2D crown ether framework coordinated with cerium ions for PEMFC applications

Abstract

We propose a novel strategy to develop sulfonated poly(arylene ether sulfone) (SPAES) composite membranes that can simultaneously improve the physicochemical stability and proton conductivity of hydrocarbon-based membranes for PEMFC applications. This strategy involves the use of a sulfonated poly(arylene thioether sulfone)-grafted 2D crown ether framework coordinated with cerium3+ ions (SATS–C2O–Ce) as a promising filler material. SATS-C2O, a highly sulfonated polymer-grafted 2D framework containing crown ether holes in its skeletal structure, was prepared via self-condensation using halogenated phloroglucinol as a multifunctional building unit to form C2O, followed by condensation using SATS to graft the sulfonated polymer onto its edge. Ce3+ ions were directly coordinated within the crown ether holes of SATS-C2O via a simple doping process using aqueous Ce solution. The SPAES composite membranes containing SATS–C2O–Ce (SPAES/SATS–C2O–Ce) exhibited exceptional dimensional stability and mechanical toughness. The remarkable chemical stability of SPAES/SATS–C2O–Ce compared to that of pristine SPAES and SPAES/Ce (containing the same amount of Ce3+ ions but without SATS-C2O) was attributed to the well-dispersed state of Ce3+ ions within the SPAES matrix. Furthermore, the enhanced proton conductivity of SPAES/SATS–C2O–Ce surpassed those of pristine SPAES, SPAES/C2O, and SPAES/Ce by the formation of additional proton-conducting channels provided by the sulfonic acid groups of SATS–C2O–Ce, along with the improved water uptake capability of SPAES. © 2024 Elsevier B.V.