Engineering Low-Resistance Heterogeneous Nanofluidics for Ultrahigh Osmotic Energy Conversion

Emerging heterogeneous nanofluidics are promising alternatives for harvesting sustainable and clean osmotic energy, primarily due to their capability to reduce Gibbs free energy dissipation. However, the misalignment of nanochannels across different layers in heterogeneous nanofluidics results in low ion flux and high transport resistance, thereby limiting their practical applications. Here, we develop a continuous in situ growth strategy to construct heterogeneous metal–organic framework nanofluidics (H-CuMOF-NMs) that contribute to an enhanced ion flux of 1.13 × 10¹⁴ ions s^–1. The channel-structure-matched nanochannels substantially reduce the transport resistance for Na⁺ ions to selectively pass through heterogeneous interfaces, as corroborated by theoretical simulations. Consequently, an impressive output power density of 12.1 W m^–2 is achieved by mixing natural seawater and river water. Large-scale H-CuMOF-NMs measuring 20 × 40 cm² are successfully manufactured as commercial membrane stacks capable of continuously powering electrical devices. The proposed nanofluidics show significant potential in separation processes and energy conversion.