Comprehensive study of Al-doped BaTiO3 ceramics: From doping optimization to electromechanical enhancement for piezoelectric applications

BaTiO 3 piezoelectric ceramics are mainly used for capacitors. However, their potential as sensors and transducers remains limited due to their moderate piezoelectric sensitivity and energy conversion efficiency. Furthermore, most dopants used for enhancing piezoelectricity often reduce the Curie temperature, restricting thermal stability. In this work, aluminium-doped BaTiO 3 ceramics were synthesized by solid-state reaction with compositions: (1−x) BaTiO 3 –xBaAlO 2.5 (x = 0–0.05). The objective was to investigate the role of Al on structural, dielectric, electromechanical properties, and electrical fatigue cycling. Al incorporation modified sintering kinetics and created oxygen vacancies, thereby influencing lattice parameters, grain growth, and electromechanical properties. At x=0.04, the ceramics showed optimal performance with: d 33 =290 pC/N, d 33 *=297 pm/V, kp=38%, Qm=72, g 33 =12.10 -3 Vm/N and figure of merit d 33 .g 33 = 3.5×10 −12 m 2 /N, while maintaining a Tc of ~122 °C and a Pr retention of 92.8% after 10 6 cycles . These results highlight aluminium-doped BaTiO 3 as a well-balanced, lead-free alternative for piezoelectric applications.