Quasi-ballistic ion transport in a vertical microrod enabling efficient evaporation-driven power generation

Abstract

Evaporation-driven power generation harnesses atmospheric thermal energy via streaming potential, but sluggish, non-directional fluid flow causes waste heat dissipation, limiting the power density. Here we demonstrate a machine learning-guided vertical microrod generator (VMG) that generates a directional Laplace pressure gradient for rapid fluid flow, thereby realizing quasi-ballistic ion transport. VMG delivers 21.5% power conversion efficiency and 14.3 W m−2 power density, with stability over 30 days under ambient conditions and retaining the efficiency over 20% across 30 K ambient temperature span. Integrated VMG arrays can power commercial devices, including emergency lights and 36 W ceiling lamps. This work achieves efficient conversion of low-power-density atmospheric thermal energy into electricity, offering a practical pathway for reliable off-grid power supply.