Pyroelectric energy harvesting capabilities and electrocaloric effect in lead-free SrxBa1-xNb2O6 ferroelectric ceramics

Abstract

SrxBa1-xNb2O6 ceramics were prepared via the high-temperature solid-state reaction method. Structural, ferroelectric, electrocaloric effect and pyroelectric energy harvesting capabilities of SrxBa1-xNb2O6 ceramics were reported. The main structural phase of tetragonal tungsten bronze with Sr-doped was detected by X–ray diffraction. It was found that the ferroelectric hysteresis loops became slimmer after the temperature higher than Curie temperature of SrxBa1-xNb2O6 ceramics, which was a representative feature of relaxor ferroelectric. In addition, we presented the positive peak values of electrocaloric at vicinity of Curie temperature which was affected by the applied electric field for all samples. It is worth noting that the pyroelectric energy harvesting property is the first time investigated by using Olsen cycle for SrxBa1-xNb2O6 ceramic. The maximum pyroelectric energy harvesting density was 170 kJ m−3 for x = 0.6 in SrxBa1-xNb2O6 with the temperature range from 293 to 433 K. The experimental results indicated that better pyroelectric energy harvesting property and larger electrocaloric effect of SrxBa1-xNb2O6 ceramic benefited from the higher Sr/Ba ratio. Finally, energy-storage capacity for SrxBa1-xNb2O6 ceramic was obtained from the ferroelectric hysteresis loop and the maximum room-temperature energy-storage efficiency was 86.37% with x = 0.6 under 60 kV cm−1.