Enhancing the dielectric relaxor behavior and energy storage properties of 0.6Ba(Zr0.2Ti0.8)O3–0.4(Ba0.7Ca0.3)TiO3 ceramics through the incorporation of paraelectric SrTiO3

Recently, relaxor ferroelectric materials have been attracting considerable attention as energy storage capacitors due to their potential applications in pulsed power systems. In this work, lead-free (1−x)[0.6Ba(Zr0.2Ti0.8)O3–0.4(Ba0.7Ca0.3)TiO3]–xSrTiO3 [(1−x)BZCT–xSTO] relaxor ceramics have been synthesized and their relaxor behavior is modulated via STO doping content. The incorporation of STO weakens the ferroelectric long-range order in BZCT, which favors the relaxor behavior, as experimentally proved by temperature dependent dielectric spectroscopy and polarization–electric field studies. The compositional dependence of energy storage properties in (1−x)BZCT–xSTO ceramics gave the optimum value at x = 0.15. Further, 0.85BZCT–0.15STO ceramics show the highest energy storage performance with a recoverable energy density of 0.987 J/cm3, efficiency of 84%, and high power density of 1.93 × 105 W/cm3 at an electric field of 108 kV/cm. Our ceramics show superior performance compared to previously reported values in BZCT based lead-free ceramics. The results reported here demonstrate that (1−x) BZCT–xSTO ceramics are potential candidates for energy storage capacitor applications.This work was supported by (i) DST-SERB, Govt. of India through Grant ECR/2017/000068 and (ii) UGC through Grant Nos. F.4-5(59-FRP/2014(BSR)). The authors AR Jayakrishnan acknowledges Central University of Tamil Nadu, India for his Ph.D. fellowship. K.V.A. acknowledges the DST for the Inspire fellowship IF170601. The author KK acknowledges DST –SERB for the fnancial support through grant no: ECR/2017/002537. The authors JPBS and MJMG acknowledge Portuguese Foundation for Science and Technology (FCT) for the fnancial support through the framework of the Strategic Funding UID/FIS/04650/2019