Enhancing the efficiency of energy harvesting from salt gradient with ion-selective nanochannel

Abstract

The development of a nanofluidic energy harvesting system plays a fundamental role in harvesting osmotic power from Gibbs free energy within the salt concentration gradient, which is considered to be a clean and renewable energy source for the future. In this study, a silica-nanochannel based nanofluidic energy harvesting system was fabricated and the output power density reached 705 W m−2 under suitable KCl concentration bias which exceeded—by almost two orders of magnitude—the results obtained by previous work. The enhancement of energy harvesting was mainly ascribed to the appropriate length of nanochannel that provides a good balance between the desirable ion selectivity and the unfavorable large resistance from the nanochannel. This high-performance nanofluidic energy device could be used in a variety of applications, including to power tiny biomedical devices or for constructing future clean-energy recovery plants.