ABSTRACT 

Evapotranspiration is a fundamental process in earth’s hydrological cycle, facilitating massive energy exchange between the land and atmosphere through water phase transitions; yet much of this energy remains untapped. Inspired by this natural phenomenon, we present a bio-inspired evapotranspiration-driven hydrokinetic power cell (ET-HPC) that mimics plant transpiration process for sustainable energy harvesting. The device features a scalable porous melamine 3D-porous framework coated with a functional biopolymer composite as the active layer, coupled with a superabsorbent sodium polyacrylate hydrogel as the water reservoir. This design achieves a high open-circuit voltage (Voc) of 0.8 V, and an impressive current density (Jsc) of 136 µA cm− 2 , comparable with those reported for many recent hydrovoltaic technologies. The electricity-generation mechanism was systematically analysed, considering surface functional groups, electrode configuration and diverse environmental conditions. In addition, the scalable integration of ET-HPC in series and parallel configurations enabled precise power modulation for wearable and portable electronics, demonstrating it as promising eco-friendly energy harvesting platform for sustainable applications in a low-carbon future.