  Scale-up of flow-electrode capacitive deionization is hindered due to the
reliance on thick brittle graphite current collectors. Inspired by developments
of electrochemical technologies we present the use of flexible membrane
electrode assemblies (MEA) to solve these limitations. We tested different
carbon-fiber fabrics as current collectors and laminated them successfully with
ion-exchange membranes. The use of thinner ion-exchange membranes is now
possible due to the reinforcement with the carbon fiber fabric. Desalination
experiments reveal that a MEA setup can achieve salt transfer rates equal to
standard setups. Hence, we deduce that charge percolation also acts outside the
electric field. In a single point of contact, ionic and electric charges are
exchanged at the carbon surface of the MEA. The use of thinner membranes leads
to a reduced potential drop. Together with a more homogeneous electric field
across the feed water section, this can compensate for the reduction of contact
surface between flow electrode and current collector.

Applied Physics