Flexible, bilayered piezoelectric composite based on large-scale inorganic PZT film and organic P(VDF-TrFE) membrane for mechanical energy harvesting

Abstract

Piezoelectric composites based on organic fluoropolymers and inorganic ceramic are attractive for mechanical energy harvesters due to their intriguing attributes of mechanical flexibility and piezoelectricity. However, the poor dispersion and random distribution of ceramic fillers in the polymer matrix not only decrease the toughness but also produce poor electrical performance. Here, a novel flexible piezocomposite with a bilayered structure based on large-sized inorganic PbZr0.52Ti0.48O3 (PZT) thin film and organic P(VDF-TrFE) membrane is developed via a simple layer-by-layer method. To realize flexibility, PZT film are fabricated on unique two-dimensional mica substrate. Then P(VDF-TrFE) membrane with polar β-phase is in situ coating on the surface of the PZT film. The resulting composite can effectively convert external strain into electrical signals with output voltage of 4 V and current of 180 nA in a bending-releasing mode of 60°. Experiment and finite element simulations illustrate that the output performance in the bilayered composite is optimized due to the synergistic effect of PZT and P(VDF-TrFE) functional layers. Besides, the composite based energy harvesters can be employed in versatile dynamics monitoring from daily physiological motions to human-machine interface. This study proposes a feasible approach to design high-performance flexible piezoelectric composite, possibly contributing to the blossoming of wearable/portable electronics.