A self-sustaining pyroelectric nanogenerator driven by water vapor

Highlights: • A self-sustaining water vapor-driven pyroelectric nanogenerator (PNG) is achieved. • The large-area flexible PNG is readily made of commercial available components. • Fast temperature oscillation is achieved by water condensation and evaporation. • The powerful PNG can drive a low-power electronic device to work continuously. Energy harvesting via pyroelectric nanogenerators (PNGs) is emerging as an attractive way to utilize waste heat. However, most of current PNGs need mechanical or electrical alternating devices to achieve the fast temperature oscillation, which is the key for PNGs to work. Herein we report a self-sustaining polymeric PNG driven by water vapor, without any energy-consuming alternating devices. Due to the high latent heat of water vapor, a fast temperature oscillation up to 23 °C/s was achieved by automatic water condensation and evaporation on the surface of the PNG. Thus, the PNG based on commercial polyvinylidene difluoride polymer was able to output an open-circuit voltage of 145 V and a short-circuit current of 0.12 μA/cm². The peak power density was 1.47 mW/cm³ by volume and 4.12 μW/cm² by area, which is comparable to previously reported PNGs relying on alternating devices. Our PNG could provide uninterrupted electricity to drive a low-power electronic device (such as a digital watch) to work continuously. The electricity could also be stored in a capacitor for high-power tasks, such as flashing multiple blue LED lights once per minute. The self-sustaining PNG driven by water vapor provides a new strategy for efficiently recovering energy from hot water vapor that are wasted in industry and in our daily life.