High-performance nanofluidic osmotic power generation enabled by exterior surface charges under the natural salt gradient

High-performance osmotic energy conversion (OEC) requires both high ionic selectivity and permeability in nanopores. Here, through systematical explorations of influences from individual charged nanopore surfaces on the performance OEC, we find that exterior surface low-concentration side (surfaceL) is essential to achieve high-performance power generation, which can significantly improve simultaneously. Detailed investigation transport indicates electric double layers near provide high-speed passages for counterions. The surfaceL enhances cation diffusion enlarging effective diffusive area, inhibits anion by electrostatic repulsion. Different areas have been considered mimic membranes with different porosities practical applications. Through adjusting width ring region surfaceL, single nanopores increases 0.3 3.4 pW a plateau at ~200 nm. density 4200 4900 W/m2 then decreases monotonously reaches commercial benchmark ~480 While, efficiency be promoted 4% 26%. Our results useful guide design nanoporous harvesting.