Highly durable, perfluorinated Q(PFBE-co-VBC) and PVDF blend anion exchange membranes with interconnected morphological features for electrochemical energy conversion systems

Abstract

Alkaline anion exchange membranes (AAEMs) have drawn more attention in recent days due to the ample advantages that the membranes possess for potential applications in electrochemical systems. In an attempt to make a highly conducting and stable anion exchange membrane, this work is devoted to the development of a morphologically tailored, partially fluorinated anion exchange polymer with quaternary ammonium functionalities. Herein, the quaternized partially fluorinated anion exchange polymers are prepared via an easy and facile synthetic route, which is a unique and new approach in the research domain of anion exchange membranes. Structural confirmation of the synthesized partially fluorinated aromatic copolymers was accomplished by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopic analyses. The morphological features of the anion exchange membrane with an interconnected network structure as revealed by microscopic techniques are rather interesting. Thermal analysis revealed the high thermal stability of these copolymers and their corresponding anion exchange membranes. The optimized anion exchange membrane with a proper ratio of anion exchange polymer and poly(vinylidene fluoride) (PVDF) showed an ionic conductivity as high as 1.0 × 10⁻² S cm⁻¹ and an ion-exchange capacity of 1.7 mmol g⁻¹; a membrane electrode assembly comprising the developed membrane and Ni@Ni-foam electrodes demonstrated stable performance for ∼200 h in a water electrolyser cell.