High thermal stability of energy storage density and large strain improvement of lead-free Bi-0.5(Na0.40K0.10)TiO3 piezoelectric ceramics doped with La and Zr

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 (similar to 1.00 J/cm(3)) 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 similar to 3% (at 75-150 degrees C). Furthermore, the x = 0.030 and 0.040 samples have the highest energy storage efficiency (ii) value of 94% at 125 degrees C with high thermal stability (eta = 84-95% at 25-150 degrees C). The x = 0.005 sample has high electric field-induced strain (S-max = 0.42%) and high normalized strain coefficient (d(33)* = S-max/E-max = 700 pm/V) with large improvements (similar to 200% and 163% for S-max and d(33)*, respectively), as compared to the based composition. This ceramic system has potentials for piezoelectric and/or energy storage density applications.