Multifunctionality of lead-free BiFeO3-based ergodic relaxor ferroelectric ceramics: High energy storage performance and electrocaloric effect

摘要

With industrializations speeding up, the need for materials with multiple functions are growing because of ever-increasing complexity of electronic devices. The BiFeO3- based ferroelectric relaxor ceramic as a multifunctional material has been ignored thus far. This work innovatively investigates the multifunctionality in a novel lead-free BiFeO3 -BaTiO3-(Sr0.7Bi0.2)TiO3 relaxor ferroelectric ceramics since a high energy storage performance and electrocaloric effect are simultaneously obtained. Results show that a large adiabatic temperature change Delta similar to 1.44 K is achieved. The total energy storage density (Ws) reaches to -2.34 J/cm 3 , recoverable energy storage density (W-R) are similar to 1.74 J/cm(3), accompanied by a high efficiency eta similar to 74%. The charge- discharge characterizations indicate that this ceramic possesses an ultrahigh current density of 1184.7 A/cm(2) and power density of 59.2 MW/cm(3). In particular, the discharging speed is ultra-fast and the discharging period tau is in range of 25-30 ns at room temperature. This work strongly indicates that the studied ceramic is a promising candidate in multifunctional applications such as cooling devices and pulsed power electronics and also enrich the species of the lead-free materials in multifunctionality. (C) 2019 Elsevier B.V. All rights reserved.