High thermal stability of energy storage density and large strain improvement of lead-free Bi0.5(Na0.40K0.10)TiO3 piezoelectric ceramics doped with La and Zr

• Published in: Journal of the European Ceramic Society 2018-09, Vol.38 (11), p.3822-3832
• Main Authors: Butnoi, Pichitchai, Manotham, Supalak, Jaita, Pharatree, Randorn, Chamnan, Rujijanagul, Gobwute
• Format: Article
• Language: English
• Subjects: BNKT; Electric field-induced strain; Energy storage density; La-doped; Lead-free ceramics
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2018.04.024

Properties of lead-free Bi0.5-xLaxNa0.40K0.10Ti0.98Zr0.02O3 (x = 0.000–0.040) ceramics were investigated. All ceramics have a pure perovskite structure. A high energy storage density (∼1.00 J/cm3) at room temperature (RT) is noted for the x = 0.030 sample, while x = 0.020 and 0.040 samples have very high thermal stability of energy storage density of ∼3% (at 75–150 °C). Furthermore, the x = 0.030 and 0.040 samples have the highest energy storage efficiency (η) value of 94% at 125 °C with high thermal stability (η = 84–95% at 25–150 °C). The x = 0.005 sample has high electric field-induced strain (Smax = 0.42%) and high normalized strain coefficient (d*33 = Smax/Emax = 700 pm/V) with large improvements (∼200% and 163% for Smax and d*33, respectively), as compared to the based composition. This ceramic system has potentials for piezoelectric and/or energy storage density applications.