Preparation of Ptfe-Reinforced Anion Exchange Membranes Using Poly (Vinyl Benzyl Chloride-Co-Vinyl Imidazole) Functionalized with 1, 2-Dimethyl-Imidazole and Their Electrochemical Properties for Water Electrolysis

Abstract

Anion exchange membrane water electrolysis (AEMWE) technology undergoessignificant advancements in recent decades, facilitating the development of anion exchange membranes (AEMs). As a critical component in membrane electrode assemblies, the design and fabrication of high‑quality AEMs with strong mechanical properties, excellent ionic conductivity, and substantial alkaline durability are essential. This study presents innovative AEMs fabricated by pore‑filling 4‑vinyl benzyl chloride (VBC) and 1‑vinylimidazole (VIm) monomers with benzoyl peroxide initiators into microporous polytetrafluoroethylene (PTFE) supports by varying substrate thicknesses (20, 50, and 100 µm), followed by free‑radical thermal polymerization, which is subsequently modified with dimethyl imidazole to incorporate imidazolium functional groups. The physicochemical and electrochemical properties of reinforced composite membranes are characterized by varying monomer ratios and substrate thicknesses for applicability in AEMWE. The optimized PBIm membrane with the 100 µm PTFE support membrane achieves an excellent cell performance of 2.4 A cm⁻² at 2.0 V in a water‑electrolysis single‑cell test (1 M KOH solution at 80 °C). This study offers valuable insights into the advancement of reinforced membrane technology for large‑scale practical applications.

Keywords: Anion exchange membrane, PTFE-reinforced composite membrane, water electrolysis