Dielectric, piezoelectric properties and temperature stability in modified (Na,K,Li)(Nb,Ta)O3 ceramics for piezoelectric energy harvesting device

In this study, modified (Na,K,Li)(Nb,Ta)O3((Na x K1-x )0.96Li0.04(Nb0.90Ta0.10) 0.998Zn0.005O3) ceramics were fabricated using a normal sintering technique. The dielectric and piezoelectric properties of the resulting ceramics were studied with special emphasis on the varying sodium concentration. The results of X-ray diffraction patterns show that the specimen exhibits an orthorhombic perovskite phase structure. High physical properties of d33 = 261 pC/N, kp = 0.44, er = 735, ρ = 4.53 g/cm3 and d33 · g33 = 10.47 pm2/N were obtained from the composition ceramics with x = 0.56 at room temperature. Δkp/kp20°C and Δf r/f 20°C showed the maximum value of 0.034 and −0.025 at 40 °C and 50 °C, respectively. Also, the temperature stability of d33, g33 and d33 · g33 of specimen with x = 0.56 was an excellent. Therefore, it is considered that the temperature stability of electrical properties is suitable for the applications of piezoelectric actuator, sensor and energy harvester.