title: Friedel-Crafts Crosslinked Highly Sulfonated Polyether Ether Ketone (SPEEK) Membranes for a Vanadium/Air Redox Flow Battery.
abstract: Highly conductive and low vanadium permeable crosslinked sulfonated poly(ether ether ketone) (cSPEEK) membranes were prepared by electrophilic aromatic substitution for a Vanadium/Air Redox Flow Battery (Vanadium/Air-RFB) application. Membranes were synthesized from ethanol solution and crosslinked under different temperatures with 1,4-benzenedimethanol and ZnCl2 via the Friedel-Crafts crosslinking route. The crosslinking mechanism under different temperatures indicated two crosslinking pathways: (a) crosslinking on the sulfonic acid groups; and (b) crosslinking on the backbone. It was observed that membranes crosslinked at a temperature of 150 °C lead to low proton conductive membranes, whereas an increase in crosslinking temperature and time would lead to high proton conductive membranes. High temperature crosslinking also resulted in an increase in anisotropy and water diffusion. Furthermore, the membranes were investigated for a Vanadium/Air Redox Flow Battery application. Membranes crosslinked at 200 °C for 30 min with a molar ratio between 2:1 (mol repeat unit:mol benzenedimethanol) showed a proton conductivity of 27.9 mS/cm and a 100 times lower VO2+ crossover compared to Nafion.
authors: Faculty of Dentistry, McGill University, 3640 University street, Montreal, QC H3A0C7, Canada. geraldine.merle@mail.mcgill.ca.
authors: Géraldine
authors: G
authors: Merle
authors: Functional and Interactive Polymers, DWI RWTH Aachen University, Forckenbeckstrae 50, D-52074 Aachen, Germany. horvat@dwi.rwth-aachen.de.
authors: Filipoi Carmen
authors: FC
authors: Ioana
authors: Functional and Interactive Polymers, DWI RWTH Aachen University, Forckenbeckstrae 50, D-52074 Aachen, Germany. demco@mc.rwth-aachen.de.
authors: Dan Eugen
authors: DE
authors: Demco
authors: Magneto Special Anodes B.V., Calandstraat 109, 3125 BA Schiedam, The Netherlands. michel.saakes@wetsus.nl.
authors: Michel
authors: M
authors: Saakes
authors: Department of Mechanical & Industrial Engineering, Concordia University, Montreal, QC H4B 1R6, Canada. schwan.hosseiny@yahoo.com.
authors: Seyed Schwan
authors: SS
authors: Hosseiny