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 CaBi 4 Ti 4 O 15 (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 ( P s ) 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 Ca 0.6 (Na 0.5 Bi 0.5 ) 0.4 Bi 3.97 Ce 0.03 Ti 3.925 Sc 0.075 O 15 ceramic: piezoelectric coefficient d 33 = 25.0 pC/N, remnant polarization P r = 9.28 μC/cm 2 , and coercive field E c = 76.14 kV/cm. Moreover, a significant high direct current resistivity ( ρ dc = 1.22 × 10 7 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.