Enhanced electrical performance in CaBi₄Ti₄O₁₅ ceramics through synergistic chemical doping and texture engineering

High-temperature piezoelectric materials with excellent piezoelectricity, low dielectric loss and large resistivity are highly desired for many industrial sectors such as aerospace, aircraft and nuclear power. Here a synergistic design strategy combining microstructural texture and chemical doping is employed to optimize CaBi₄Ti₄O₁₅ (CBT) ceramics with bismuth layer structure. High textured microstructure with an orientation factor of 80%–82% has been successfully achieved by the spark plasma sintering technique. Furthermore, by doping MnO₂, both advantages of hard doping and sintering aids are used to obtain the excellent electrical performance of d₃₃ = 27.3 pC/N, tanδ~0.1%, Q₃₁~2,307 and electrical resistivity ρ~6.5 × 10¹⁰ Ω·cm. Up to 600 ℃, the 0.2% (in mass) Mn doped CBT ceramics still exhibit high performance of d₃₃ = 26.4 pC/N, ρ~1.5 × 10⁶ Ω·cm and tanδ~15.8%, keeping at an applicable level, thus the upper-temperature limit for practical application of the CBT ceramics is greatly increased. This work paves a new way for developing and fabricating excellent high-temperature piezoelectric materials.