Influence of the (Bi0.5Na0.5)TiO3–BaTiO3 lead-free piezoceramic geometries on the power generation of energy harvesting devices

In this work, we report the harvested energy of lead-free 0.94(Bi0.5Na0.5)TiO3-0.06BaTiO3 bulk ceramics using two different geometries (rectangular plate and disk). These ceramics were obtained by the solid-state reaction method and their good ferroelectric properties were reported. The samples were characterized using X-ray diffraction (XRD), Raman microspectroscopy and Scanning Electron Microscopy (SEM) analysis, whereas ferroelectric and dielectric properties were evaluated by means of ferroelectric hysteresis loops and impedance spectroscopy studies. A cantilever-based harvester was proposed to evaluate the performance of Piezoelectric Energy Harvesting (PEH). The morphological influence on the voltage generation was experimentally and numerically studied by the Finite Element Method (FEM). Several cases for plate and disk-shaped piezoelectric ceramics were simulated under a constant volume restriction. Results showed a great influence of the morphology on the electromechanical response of the system. In particular, the plate featured a higher voltage generation than the disk.