Structural and electrical properties of (LiCe) co-doped (NaBi)0.5-(LiCe) Bi2Nb1.99(Co1/3W2/3)0.01O9 piezoelectric ceramics

(NaBi)0.5-x(LiCe)xBi2Nb1.99(Co1/3W2/3)0.01O9 (NBNCW-xLC, x = 0.00–0.12) ceramic samples were obtained by (LiCe) co-doping Na0.5Bi2.5Nb1.99(Co1/3W2/3)0.01O9. The conventional solid-phase method was used throughout the preparation process. The effect of (LiCe) on the crystal structure, microscopic morphology, and dielectric, ferroelectric and piezoelectric properties of NBNCW-xLC ceramics were systematically studied. The XRD, Raman, and XPS results show that the Ce ions in (LiCe) exist in two forms: Ce3+ and Ce4+. With increasing of (LiCe) doping, the grain size of the NBNCW-xLC ceramics gradually increases, and the Curie temperature gradually decreases (773-753 °C). Moreover, the decrease in impedance and increase in loss may be related to the substitution of Ce4+ for Nb5+ at the B site to produce oxygen vacancies. It is worth noting that the NBNCW-0.06LC ceramic achieves the best electrical properties, in which the piezoelectric constant (d33) is 28 pC/N, much higher than that of the Na0.5Bi2.5Nb2O9 ceramic (∼11 pC/N). A remanent polarization (Pr) of 16.3 μC/cm2 is also rarely seen in Na0.5Bi2.5Nb2O9-based ceramics. In addition, maintaining excellent d33 thermal stability at 700 °C makes (LiCe) co-doped NBNCW-xLC ceramics suitable for piezoelectric devices at high temperatures.