Deciphering the synergistic action of multiple factors inducing high piezoresponse in CaBi₄Ti₄O₁₅‐based piezoelectric ceramics

Abstract

NaBiCe/Sc ions were co‐doped into a pure CaBi4Ti4O15 (CBT) ceramic to investigate the synergistic action of multiple factors that induced a high piezoresponse. In comparison to the undoped CBT ceramic, the NaBiCe/Sc co‐doped CBT solid solution exhibited an enhancement in spontaneous polarization (Ps) attributed to the tilting of the oxygen octahedra, enhanced domain reorientation owing to increased grain size, and improved dielectric breakdown strength as a consequence of reduced porosity. The synergistic action of the aforementioned comprehensive factors resulted in excellent electrical properties of Ca0.6(Na0.5Bi0.5)0.4Bi3.97Ce0.03Ti3.925Sc0.075O15 ceramic: piezoelectric coefficient d33 = 25.0 pC/N, remnant polarization Pr = 9.28 μC/cm2, and coercive field Ec = 76.14 kV/cm. Moreover, a significant high direct current resistivity (ρdc = 1.22 × 107 Ω·cm at 500°C) was achieved, and the corresponding conductance mechanism was analyzed through a synergistic approach that combines ultraviolet–visible diffuse reflectance spectra and density functional theory.