Supersonically Sprayed Flexible ZnO/PVDF Composite Films with Enhanced Piezoelectricity for Energy Harvesting and Storage

A flexible piezoelectric nanogenerator (PENG) was developed to convert ambient mechanical energy into electrical energy. Highly crystalline template-free zinc oxide (ZnO) microrods were prepared using a wet chemical method at a low temperature. As-synthesized ZnO microrods were blended with polyvinylidene fluoride (PVDF) to prepare a piezoelectric composite film using the supersonic spraying method. A PENG electrode comprising ZnO microrods (0.5 g) produced 15.2 V under a tapping force of 20 N at 5 Hz. In addition, an output current of 32 & mu;A was produced with a maximum power density of 12.5 & mu;W cm(-2). The output voltage considering various body movements was investigated to demonstrate the flexibility and durability of the proposed PENG. Furthermore, the supercapacitive properties of ZnO/reduced graphene oxide were studied.