Optimized piezoelectric and structural properties of (Bi,Na)TiO3-(Bi,K)TiO3 ceramics for energy harvester applications

초록

We investigated (1 - x )(Bi,Na)TiO3-x(Bi,K)TiO3 (x=0, 0.14, 0.16, 0.18, 0.20, and 0.22) compositions of lead-free piezoelectric ceramics for potential energy harvester applications. Composition and sintering temperature of (1 - x)(Bi,Na)TiO3-x(Bi,K)TiO3 were varied to extract the optimized processing temperature with each composition. We compared and analyzed sintering temperature-dependent surface morphologies and electrical properties. Maximum piezoelectric charge constant of 180 pC/N were obtained from the 0.8(Bi,Na)TiO3-0.2(Bi,K)TiO3 composition at the sintering temperature of 1180 degrees C. Temperature dependent dielectric permittivity was measured to know the phase transition. We corresponded two different anomaly peaks, observed at 84 and 290 degrees C, as the rhombohedral-tetragonal and tetragonal-cubic phase transitions, respectively. Due to these phase transitions, different shapes of polarization -electric field loops (P-E loops) were measured and compared. Finally, output power of 42.39 nW/cm(2) were obtained for the (1 - x)(Bi,Na)TiO3-x(Bi,K)TiO3 lead free piezoelectric ceramics. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

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