Investigations on structure, ferroelectric, piezoelectric and energy storage properties of barium calcium titanate (BCT) ceramics

We investigated structural, aging induced ferroelectric, piezoelectric and energy density properties of ceramic (Ba 0.70 Ca 0.30 )TiO 3 (BCT) capacitors that were prepared by the solid-state reaction method. According to X-ray (XRD) data, along with BaTiO 3 tetragonal peaks, CaTiO 3 rich orthorhombic peaks were also observed at room temperature. Raman scattering gives evidence for the formation of oxygen vacancies in BCT due to partial migration of Ca 2+ into Ti 4+ site. Abnormal double like hysteresis polarization-electric field ( P – E ) loops were observed at room temperature for naturally aged BCT ceramics. Strain-electric field ( S – E ) loops confirm piezoelectric behavior. Room temperature (300 K) charge curve and discharge curve energy densities [( Ed ) c ∼ 0.35 (before aging) 0.39 J/cm 3 (aged)], [( Ed ) d ∼ 0.20 (before aging) 0.24 J/cm 3 (aged)], respectively, at a maximum electric field ∼50 kV/cm. The bulk BCT materials have shown interesting energy densities with good energy storage efficiency (∼58% before aging, ∼61% after aging) suggesting they might be strong candidates for high energy density capacitor applications.