A water-evaporation-induced self-charging hybrid power unit for application in the Internet of Things

Abstract A self-charging hybrid power unit has been developed by integrating a water-evaporation-induced nanogenerator with a flexible nano-patterned supercapacitor. The nanogenerator can harvest environmental thermal energy and mechanical energy through the water evaporation process, and the supercapacitor can be charged simultaneously. The former offers stable electrical power as output, whereas the Ppy-based supercapacitor shows a capacitance of 12.497 mF/cm 2 with 96.42% retention after 4,000 cycles. After filling the power unit with water as the fuel, it can be fully charged in about 20 min. The power unit can be flexibly integrated with electronic devices such as sensor nodes and wireless transmitters employing the Internet of Things. This new approach can offer new possibilities in continuous future operation of randomly distributed electronic devices incorporated in the Internet of Things.