Thermal-stability of the enhanced piezoelectric, energy storage and electrocaloric properties of a lead-free BCZT ceramic.

The lead-free Ba 0.85 Ca 0.15 Zr 0.10 Ti 0.90 O 3 (BCZT) relaxor ferroelectric ceramic has aroused much attention due to its enhanced piezoelectric, energy storage and electrocaloric properties. In this study, the BCZT ceramic was elaborated by the solid-state reaction route, and the temperature-dependence of the structural, electrical, piezoelectric, energy storage and electrocaloric properties was investigated. X-ray diffraction analysis revealed a pure perovskite phase, and the temperature-dependence of Raman spectroscopy, dielectric and ferroelectric measurements revealed the phase transitions in the BCZT ceramic. At room temperature, the strain and the large-signal piezoelectric coefficient reached a maximum of 0.062% and 234 pm V -1 , respectively. Furthermore, enhanced recovered energy density ( W rec = 62 mJ cm -3 ) and high-energy storage efficiency ( η ) of 72.9% at 130 °C were found. The BCZT ceramic demonstrated excellent thermal stability of the energy storage variation (ESV), less than ±5.5% in the temperature range of 30-100 °C compared to other lead-free ceramics. The electrocaloric response in the BCZT ceramic was explored via the indirect approach by using the Maxwell relation. Significant electrocaloric temperature change (Δ T ) of 0.57 K over a broad temperature span ( T span = 70 °C) and enhanced coefficient of performance (COP = 11) were obtained under 25 kV cm -1 . The obtained results make the BCZT ceramic a suitable eco-friendly material for energy storage and solid-state electrocaloric cooling devices.