Lead-Free Textured Ceramics with Ultrahigh Piezoelectric Properties by Synergistic Design

Lead-free ceramics with superior piezoelectric performance are highly desirable in various electromechanical applications. Unfortunately, it is still challenging to achieve significantly enhanced piezoelectricity without sacrificing the Curie temperature (T_c) in current BaTiO₃-based ceramics. To address this issue, a synergistic design strategy of integrating crystallographic texture, multiphase coexistence, and doping engineering is proposed here. Highly [001]_c-textured (Ba_0.95Ca_0.05)(Ti_0.92Zr_0.06Sn_0.02)O₃ ceramics are synthesized through Li-related liquid-phase-assisted templated grain growth, with improved grain orientation quality (f of ∼96% and r of ∼0.16) achieved at substantially reduced texture temperatures. Encouragingly, ultrahigh comprehensive piezoelectric properties, i.e., piezoelectric coefficient d₃₃ of ∼820 pC N^-1, electrostrain S_max/E_max of ∼2040 pm V^-1, and figure of merit d₃₃ × g₃₃ of ∼23.5 × 10^-12 m² N^-1, are simultaneously obtained without sacrificing T_c, which are also about 2.3, 2.4, and 4.3 times as high as those of non-textured counterpart, respectively. On the basis of the experiments and theoretical modeling, the outstanding piezoelectric performance is attributed to more effective exploration of property anisotropy and easier polarization rotation/extension, owing to improved grain orientation quality, dissolution of templates into oriented grains, coexisting R + O + T phases, and domain miniaturization. This work provides important guidelines for developing novel ceramics with outstanding piezoelectric properties and can largely expand application fields of textured BaTiO₃-based ceramics into high-performance and multilayer electronic devices.