Infrared-driven poly(vinylidene difluoride)/tungsten oxide pyroelectric generator for non-contact energy harvesting

Abstract

Wasted heat has been regarded as one of the most important and widely available renewable energy sources worldwide, and a lot of attention has been paid to harvesting ambient wasted thermal energy. In this study, a novel infrared (IR)-driven non-contact pyroelectric generator based on electrospun poly(vinylidene fluoride) (PVDF) nanofibrous membranes is developed for converting photothermal energy into useful electrical energy. Here, we incorporate a photothermal conversion material: reduced tungsten oxide (WO2.72), into PVDF to enhance the heat transfer of PVDF/WO2.72 nanofibrous membranes, which is due to their excellent IR absorbance. Meanwhile, partially covered electrodes are used to achieve faster and larger temperature fluctuations, which further improve pyroelectric energy transformation. Under IR irradiation, the temperature of the PVDF/WO2.72 pyroelectric composites containing 7 wt% WO2.72 rapidly rises to 107.1 °C after 60 s, which is 41.5 °C higher than that of the WO2.72-free PVDF composites. The maximum output voltage of the WO2.72-free PVDF composites is 0.5 V, while that of the 7 wt% PVDF/WO2.72 composites is three times higher, and reaches 1.5 V. Moreover, the 7 wt% PVDF/WO2.72 composites also presents good pyroelectric energy output stability and durability.