Thermal Energy Harvesting Capabilities in Lead-Free Ba0.85Ca0.15Ti0.9-xSnxZr0.10O3 Ferroelectric Ceramics

The energy harvesting potential in bulk lead-free Ba0.85Ca0.15Ti0.9-xSnxZr0.10O3(BCT-BZT-Sn) ferroelectric ceramic has been investigated. All the compositions (x = 0.01, 0.02, 0.04, and 0.06) were fabricated by the solid-state reaction route and possessed a single-phase perovskite structure, whereas a small amount of secondary phase was observed in the x = 0.06 sample. The Olsen cycle was used to estimate the enhanced thermal energy harvesting performance over a wide range of temperatures and electric field strengths. The energy conversion density increases up to x = 0.02 and decreases thereafter owing to a reduction in the hysteresis loop area. The maximum energy conversion density for the BCT-BZT-Sn composition were found to be 306 kJ/m(3),332 kJ/m(3),226 kJ/m(3) and 167.6 kJ/m(3) for x = 0.01, 0.02, 0.04 and 0.06, respectively, for a temperature range of 303-373 K and an electric field of 1-29 kV/cm. These values are three times higher than that of the soft PbZrTiO3 which has an almost equivalent piezoelectric performance as Ba0.85Ca0.15Ti0.9Zr0.10O3 at room temperature. The obtained energy conversion is also higher than most other lead-based and lead-free ferroelectric bulk materials.