Improved Li and Sb doped lead-free (Na,K)NbO3 piezoelectric ceramics for energy harvesting applications

Abstract

Piezoelectric energy harvesting is the most widely investigated technology for renewable energy applications. In this work, (1-x)(Na0.5K0.5)NbO3-xLiSbO3 piezoelectric ceramics were prepared through conventional mixed oxide fabrication methods with different sintering temperatures. Although the (Na0.5K0.5)NbO3 piezoelectric material is representative among the lead-free ceramics, it is difficult to densify by typical sintering techniques owing to its easy evaporation properties of potassium (K+) and sodium ion (Na+). Hence, lithium (Li+) and antimony ion (Sb5+) were used for the partial substitution of (Na0.5K0.5)NbO3. With the optimized sintering temperature, Li+ and Sb5+ are expected to be crucial in increasing the density and enhance the piezoelectric and ferroelectric properties. In this study, the phase, microstructure, and dielectric and electrical properties of (1-x)(Na0.5K0.5)NbO3-xLiSbO3 ceramics depending on the sintering temperature is examined by employing X-ray diffraction, field emission scanning electron microscopy, impedance analyzer, and mechanical force system for energy harvesting.