Graphene oxide incorporated flexible and free-standing PVDF/ZnO composite membrane for mechanical energy harvesting

Here we report the comparative study of mechanical energy harvesting properties of highly flexible, stretchable and free-standing poly (vinylidene fluoride) (PVDF) membranes loaded with various nanofillers like zinc oxide (ZnO), graphene oxide (GO) and ZnO/GO composites. Composite polymer membranes with dominating β-crystalline phase have been synthesized by effectively simpler and low-cost chemical synthesis method. The mechanical to electrical energy conversion is observed by measuring output voltage and current signal while repetitive mechanical stress is applied to the composite membranes in different modes like tapping, bending and stretching. Sufficient increment in open circuit voltage and short circuit current is observed in each mode of mechanical vibrations applied to both ZnO and GO loaded composite membranes compared to the pristine PVDF host matrix. The enhancement in output deliverable electrical power is attributed to the polar nature of ZnO and the formation of GO conduction network in composite membranes. The self-poled β-crystalline tri-phase PVDF/ZnO/GO composite membranes demonstrate the best energy harvesting performances among all the composites in each mode of mechanical stresses, making them suitable for flexible nanogenerators.