Piezoelectric and structural properties of bismuth sodium potassium titanate lead-free ceramics for energy harvesting

The development of piezoelectric ceramics with high energy conversion efficiency is of decisive importance for the requirements of the advanced energy harvesting devices toward miniaturization and integration. Lead titanate-zirconate (PZT) piezoceramics are the most widely used energy harvesting (EH) materials due to their excellent piezoelectric properties. However, the presence of more than 60% lead in the PZT composition is a serious threat to human health and the environment. Consequently, greater efforts being made to develop lead-free alternatives to PZT-based materials. Here, we propose the Bi 0.5 (Na 0.8 K 0.2 ) 0.5 TiO 3 (BNKT) lead-free piezoceramics as a good candidate for the replacement of toxic lead compounds for energy harvesting applications. For that, we have carried out a systematic study of the voltage generation of BNKT-based piezoceramics for (EH) purposes. Specifically, the obtained piezoelectric charge coefficients (d 33 = 129 pC/N and d 31 = − 12.8 pC/N) and maximum generated output voltage (19.9 V/g) values reveal the good ferro-piezoelectric properties and potential technological applications for energy harvesting of the BNKT–based lead-free piezoceramics. Finally, we consider that the design of new lead-free piezoceramics with superior property coefficients and functionalities, such as the BNKT-based piezoceramics, should be seriously considered as candidates for the replacement of the current toxic lead-based compounds.