Piezoelectric performance enhancement of electrospun functionally graded PVDF/BaTiO3 based flexible nanogenerators

Flexible piezoelectric electrospun films have gained widespread attention due to their ability to convert mechanical energy into electrical energy. Pure PVDF has a low output, while multi-layered film based nanogenerators with high concentrations of BaTiO3 give more output. This paper aims to fabricate a functionally graded nanogenerator with varying BaTiO3 concentrations from bottom to top. Multilayer films were synthesized using electrospinning and incorporated into a piezoelectric nanogenerator (PENG) device. The PENG devices were subjected to palm tapping, wrist tapping, and elbow hitting to extract energy. The PENG generated peak-to-peak voltage of 8.22V, short circuit current of 3.36 µA, and an instantaneous power of 0.14 mW/cm2. Compared to monolayer films, functionally graded films exhibit greater piezoelectric performance as the number of nanofiber layers increases. The piezoelectric output of PENGs device is validated using Comsol Multiphysics software. This study demonstrated the first application of electrospun functionally graded nanostructures as piezoelectric nanogenerators.