Lead-free relaxor-ferroelectric ceramics for high-energy-storage applications

摘要

Relaxor-ferroelectric ceramics capacitors have been in the front lines of investigations aimed at optimizing energy density due to their highP(max), suppressedP(r), and high BDS levels, attributed to their highly dynamic polar nano-regions. A set of (1 -x)SrTiO3-x[0.88BaTiO(3)-0.12Bi(Li0.5Ta0.5)O-3] ceramics (x= 0, 20, 40, 60 and 80 mol%), abbreviated as (1 -x)ST-x(BT-BLT), was designed and fabricatedviaa solid-state reaction route. A striking energy-storage density of 2.24 J cm(-3), coupled with a high efficiency of eta= 81% at 300 kV cm(-1), was measured for these (1 -x)ST-x(BT-BLT) ceramics. The incorporation of BT-BLT ceramics was found to dramatically transform the paraelectric state of strontium titanate into the relaxor-ferroelectric state, by introducing broad relaxor behavior. The energy storage properties of the ceramic withx= 60 mol% showed outstanding stability in frequency (10-100 Hz) and temperature (20-120 degrees C), with minimal variation of (+/-<= 0.5%), over the course of 10(5)cycles. Moreover, under various electric fields, rapid charge and discharge (<= 1.5 mu s) was also observed for thisx= 60 mol% ceramic. Most significantly, the outcomes of this study are expected to provide a standard for other emerging lead-free dielectric ceramics displaying very good energy-storage properties and excellent electric field endurance, which are of pragmatic importance for cutting-edge pulsed power technology.