Preparation and Performance of the Self-crosslinking Sulfonated Poly (ether ether ketone) Proton Exchange Membrane

Side chain type, sulfonated poly (ether ether ketone) (SPEEK) was prepared via free radical addition reaction using PEEK containning 3, 3'-diallyl bisphenol A structural unit and 3-mercaptopropane-sulphonate. The structure and morphology of SPEEK membrane were characterized by Fourier transform infrared spectroscopy(FTIR), H-1 NMR, TGA and SEM. The SPEEK has high hydrophilic/hydrophobic phase separation. Water uptake, mechanical property, proton conductivity, VO2+ permeability and single cell performances were investigated in order to understand the relationship between morphology and property of the membranes. The vanadium ion VO2+ permeability through the SPFEK-4 membrane (IEC = 2. 12 mmol/g) is 1. 54x10(-6) cm(2)/min, which is lower than that of Nafion membrane( 6. 04x10(-6) cm(2)/min ). Tests of SPPEK-4 in vanadium redox batteries (VRB) demonstrate a comparable Columbic efficiency (CE) and energy efficiency (EE) to that of Nafion 117 at 50 mA/cm(2), and the SPPEK-4 membrane exhibits stable performance in cell over 50 charge-discharge cycles.