Enhanced Salinity Gradient Energy Generation through Pore Number Control in Atomically Thin MoS 2 Membrane

Salinity gradient, or “blue”, energy offers a sustainable route to convert the chemical potential difference between seawater and freshwater into electricity. Monolayer molybdenum disulfide (MoS 2 ) has recently emerged as a promising nanofluidic material owing to its atomic thickness, chemical stability, and tunable surface charge. Here, we investigate the scaling behavior of salinity-gradient energy harvesting using chemical vapor deposition (CVD)-grown monolayer MoS 2 membranes containing 20 nm nanopores suspended on silicon nitride substrates. Ion transport measurements were conducted in an automated diffusion cell with large reservoirs (10 L) to ensure stable bulk concentrations under KCl gradients from 10 to 1000. The generated osmotic power increases with nanopore number, rising from 84 nW (single pore) to 230 nW (four pores), corresponding to power densities of (0.1–0.3) × 10 6 W m –2 at low porosities (0.04–0.16%). The observed increase in current and power with rising salinity reflects surface-charge-influenced ion transport combined with high ionic flux through atomically thin nanopores. Poisson–Nernst–Planck simulations performed using experimentally relevant geometries reproduce the observed scaling trends and suggest that ionic transport through multiple nanopores can be treated as approximately additive under the present pore spacing. These findings provide fundamental insight into nanoscale ion transport and power scaling in CVD-grown MoS 2 nanopore membranes, informing the development of scalable nanofluidic blue-energy systems.