Directed charge boosting by polyelectrolyte nanorods on a graphene oxide membrane for High-Performance blue energy harvesting

Abstract

Blue energy harvesting is conversion of the Gibbs free energy of mixing due to the salinity gradient between fresh and salt water into electrical energy. Two-dimensional (2D) material-based nanofluidic channels offer unique features and distinct advantages for blue energy harvesting, and they can be prepared via simple fabrication and modification methods. However, because of their lower ion transport selectivity and conductivity than theoretical estimation due to intrinsic and structural defects, 2D nanochannels exhibit low power density and extractable power. In this study, we developed a scalable blade-coating method for the shear-induced alignment of polyelectrolyte nanorods in 2D nanochannels. Based on the increase in the directional charge density via structural modifications, devices had the developed nanochannel structure and achieved a high osmotic power density and energy conversion efficiency of 13.12 W m−2 and 35.64%, respectively. Finally, a hybrid nanofluidic tandem cell was used to operate a handheld electrical device. This study demonstrates the potential of coupling of improved charge density and modified ion pathway in the nanochannel by introducing a charge booster for osmotic energy conversion.