Low-grade energy harvesting from dispersed exhaust steam for power generation using a soft biomimetic actuator

Abstract Exhaust steam contains abundant energy, yet there is limited engineering attempt devoted to harvesting such energy, inducing tremendous energy loss. Here, we present a biomimetic actuator for energy harvesting from exhaust steam. This biomimetic actuator consists of a polyethylene oxide (PEO) layer for hydroscopic actuation and a polyvinylidene fluoride (PVDF) layer for power generation. Such PEO/PVDF actuator sustains reversible two-stage deformation in exhaust steam, delivering a maximum bending angle of 760°. A 1.5 cm× 3 cm PEO/PVDF actuator achieves peak voltages of 4, 0.5, 3, and 2 V, respectively, upon exposure to the steam generated from mouth breath, wet paper, hot water, and solar evaporator, suggesting high-potential practical integration. The generated electricity from the actuator can be rectified and stored to operate low-power electronics, such as light-emitting diodes. Our study has paved a way for the future design of advanced actuators pertinent to low-grade energy harvesting for a sustainable society.