New LDPE based anion-exchange membranes for alkaline solid polymeric electrolyte water electrolysis

In this work, a new LDPE based anion-exchange membrane was prepared by UV-induced grafting of vinylbenzyl chloride (VBC) functional monomers and their successive conversion into quaternary ammonium sites with 1,4-diazabicyclo(2.2.2)octane (Dabco). After thin film formation this material was used to prepare a MEA (membrane electrode assembly) for use in an alkaline membrane water electrolyzer. The membrane was primarily characterized by electron microscopy, FTIR and solid state NMR techniques in order to determine its structural and phase properties whereas electrochemical parameters were evaluated and compared to a commercial benchmark membrane. Experimental data showed that the electrochemical performance of the LDPE-VBC-Dabco membrane was comparable to that measured for the best commercial material, and enabled its use in an electrolytic cell for hydrogen production. The results obtained in the electrolytic cell showed a constant hydrogen production rate of about 30 cc/min over more than 500 h. However, the long time stability of the LDPE-g-VBC-Dabco membrane needs still to be improved in the alkaline environment of the working cell.