A suitable approach to achieve functional (Bi, Na)TiO3-based lead-free piezoceramics via compositional design for energy storage applications

Abstract

In this work, sodium bismuth titanate based lead-free piezoceramics with modifiable dielectric and energy storage properties by compositional modification through Nb doping (0.94Bi0.5Na0.5TiO3-0.06BaTiO3-xNb2O5) were obtained. Nb doping on 0.94Bi0.5Na0.5TiO3-0.06BaTiO3-based ceramics produces a bifunctional behavior, which is governed by controlling the structural and microstructural characteristics of the system. Whereby the incorporation of Nb+5 leads to a change from rhombohedral-tetragonal (R-T) multiphasic coexistence to a tetragonal (T) phase at room temperature (RT) and causes a decrease in average grain size. The particularly high piezoelectric coefficient (d33), in the R-T multiphase coexistence region, facilitates the polarization and leads to a higher piezoelectric response than in the T-region. Meanwhile, increasing the Nb content improves the energy storage properties and results in a storage of energy value (Wrec) up to about 0.50 J/cm3 at room temperature.