High discharge energy density in novel K1/2Bi1/2TiO3-BiFeO3 based relaxor ferroelectrics
Xinzhen Wang, Yongbo Fan, Bin Zhang, Ali Mostaed, Linhao Li, Antonio Feteira, Dawei Wang, Derek C. Sinclair, Ge Wang, Ian M. Reaney
Abstract
An increasing number of new dielectrics are being reported for the development of next-generation ceramic capacitors for power electronics used in clean energy technologies. Here, high discharge energy density (W dis ) ~6.1 J cm −3 with efficiency (η)~72% under a pulsed field (E max ) of 410 kV cm −1 is reported along with temperature stability up to 150 °C (E max = 200 kV cm −1 ) for 0.5 K 0.5 Bi 0.5 TiO 3 -0.42BiFeO 3 -0.08Sm(Mg 2/3 Nb 1/3 )O 3 (KBT-BF-SMN) bulk ceramics. The optimised composition is chemically heterogeneous but electrically homogenous, similar to several BiFeO 3 -based dielectrics reported previously and adding to the growing body of evidence that electrical (measured at weak-field) not chemical homogeneity is the best guide to increased E max and enhanced energy density. KBT-BF-SMN ceramics are therefore considered as promising candidates for pulsed power and power electronics applications. • Novel Pb-free K 1/2 Bi 1/2 TiO 3 -BiFeO 3 based high energy density ceramics. • High energy density ~6.1 J cm −3 at 410 kV cm −1 for bulk ceramics. • Desirable electrical homogeneity with highly-resistive electrical components. • Superior permittivity stability (130–600 °C) and pulsed discharge characteristics > 150 °C. • Excellent candidate for next-generation energy density ceramic capacitors.