Comprehensive optimization of piezoelectric coefficient and depolarization temperature in Mn-doped Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3-BaTiO3 lead-free piezoceramics

•A well-balanced performance of d33 and Td is achieved in MnO2-doped 0.79(Bi0.5Na0.5TiO3)-0.14(Bi0.5K0.5TiO3)-0.07BaTiO3 ternary ceramics with a mixture of T and pC phases.•The incorporation of 0.25 mol% MnO2 enhances the d33 by more than 40%, while Td remains almost unchanged (i.e., d33=181 pC/N, Td=184 °C).•Piezoelectric force microscopy (PFM) has revealed a special domain configuration, namely large striped and layered macro domains embedded with small nanodomains.