High figure of merit for electrokinetic energy conversion in Nafion membranes

Based on measurements of the streaming potential coefficient, hydraulic permeability and ion conductivity the electrokinetic energy conversion of nanoporous ion conductive Nafion®117 polymer membrane has been evaluated. A high figure-of-merit of 1.1 ± 0.2 has been found in 0.03 M aqueous LiCl solution that corresponds to an electrokinetic energy conversion efficiency of approximately 18 ± 2%. To the best of our knowledge, this is the first study in the literature designated to the electrokinetic energy conversion in materials where the pores have high surface charge density. The initial results are promising with respect to future electrokinetic generator or pump applications and highly charged polymer membranes might be a future pathway for low-cost high-efficiency electrokinetic energy conversion.