Improved Curie temperature and piezoelectric activity of K/Ce co-doped Bi 4 Ti 3 O 12 –BaBi 4 Ti 4 O 15 intergrowth structure ceramics

K/Ce co-doped Bi 4 Ti 3 O 12 –Ba 1− x (K 1/2 Ce 1/2 ) x Bi 4 Ti 4 O 15 (BBIT- x KC, 0 ≤ x ≤ 0.3) intergrowth bismuth layered piezoelectric ceramics were prepared by traditional solid-state reaction. The effects of K/Ce substitution on structure, high temperature conductivity, and piezoelectric properties of BBIT were systematically investigated. The XRD results suggest that all the samples exhibited 3–4 layers of intergrowth bismuth layered orthogonal structure, the Raman mode variation revealed the K/Ce ions enter A-site. The Curie temperature ( T c ) of BBIT ceramics has been raised. The decrease of dielectric loss and increase of impedance activation energy is related to the decrease of oxygen vacancy (O V ) concentration, which is demonstrated by XPS measurements. The BBIT-0.15KC ceramic sample has outstanding electrical properties, the remanent polarization 2 P r is 30.1 µ C/cm 2 , T c is 535 °C, and the d 33 value is 22.3 pC/N. The d 33 value remains at its original 91.9% after depolarization at 400 °C, showing good thermal stability.