Performance of K_0.5Na_0.5NbO₃-LiSbO₃-CaTiO₃ ceramics in acoustic energy harvesting exposed to sound pressure

In this paper, a numerical investigation is carried out for K_0.5Na_0.5NbO₃-LiSbO₃-CaTiO₃ ceramics for harvesting low frequency sound. For the numerical simulation, a quarter wavelength straight tube resonator with a rectangular cross section was modelled and piezoelectric laminated cantilever bimorph plates placed inside the system at uniform distance. With the application of acoustic sound pressure of a resonant frequency at the opening of tube resonator, the amplified acoustic pressure inside the tube vibrates piezolaminated bimorph plates placed inside the tube, thus generating a voltage on the surface of the piezoelectric layer. In order to generate more voltage and power in the acoustic harvesting system, multiple piezolaminated cantilever plates are placed inside the straight tube resonator. The lead-free piezoelectric material of K_0.5 Na_0.5 NbO₃ (KNN) family i.e. K_0.5Na_0.5NbO₃-LiSbO₃-(2wt %) CaTiO₃ (KNN-LS-CT) was explored as a piezoelectric material for the acoustic energy harvesting system. With the application of acoustic sound pressure of 1dB at the opening of the tube, an output voltage of maximum 3.8 V is measured numerically at resonant frequency of 194 Hz while the maximum power calculated is 2 µW. The numerical results reveal the potential of the lead-free piezoelectric materials for acoustic energy harvesting applications.