A flexible piezoelectric film for fluid energy harvesting using wake-induced vibration

With the development of Internet of Things technology, piezoelectric energy harvesters have an increasing demand for high-performance and high-stability piezoelectric materials. In consideration of the large mass and rigidity in the traditional piezoelectric sheets, a piezoelectric film was fabricated using electrospinning technique, which was compared with the Macro Fiber Composite (MFC) by a wake-induced vibration wind tunnel experiment. The power density, vibration response and output voltage were investigated and the stability tests under three types of high-cycle deformations, varying temperature and humidity were carried out. Results demonstrated that the piezoelectric film exhibited good environmental adaptability and achieved the normalized maximum power density at a wind speed of 3 m/s, which was 46.5 % higher than that of MFC. Within the wind speed range of 1 m/s to 5 m/s, the output voltage rose from 229.6 mV to 319.3 mV, exhibiting a robust linear relationship with vibration displacement. More importantly, the output voltage remained stable after undergoing 107 cycles of stretching, bending and twisting, with no failures observed. However, during the tensile test, after the cycle count increased to 107, the output voltage of the MFC dropped to 0. Furthermore, in the torsion test, the output voltage of the MFC presented an irregular curve. This research not only facilitated the application of new piezoelectric films in energy harvesting from wake-induced vibrations but also provided significant theoretical and technical support for related fields.