Effect of ion current rectification on energy harvesting by reverse electrodialysis

In this paper, we investigate the effect of `diode like' ion current rectification on energy harvesting based on reverse electrodialysis for the first time. Even though the rectification nanodevices based on asymmetric nanopores and nanochannels had been reported previously, they were not proper to be applied for energy harvesting owing to their intrinsic low current. This problem is overcome by our proposed asymmetric nanochannel networks membrane (NCNM), which allows high flux transportation without losing rectification ratio. This study shows that the directionality of ion transport can be controlled by the cooperation and competition between the directional ion transport induced from asymmetric geometry in microchannel and the diffusive ion transport from electrolyte concentration gradient. Also, it was shown that the anisotropic ion transport control can improve the power efficiency from electrolyte gradient.