Energy storage performance and phase transition under high electric field in Na/Ta co-doped AgNbO3 ceramics
Mingyuan Zhao, Jing Wang, Hao Yuan, Zehan Zheng, Lei Zhao
Abstract
Lead-free antiferroelectric ceramics with high energy storage performance show great potential in pulsed power capacitors. However, poor breakdown strength and antiferroelectric stability are the two main drawbacks that limit the energy storage performance of antiferroelectric ceramics. Herein, high-quality (Ag1-xNax)(Nb1-xTax)O3 ceramics were prepared by the tape casting process. The breakdown strength was greatly improved as a result of the high density and fine grains, while the antiferroelectric stability was enhanced owning to the M2 phase. Benefiting from the synergistic improvement in breakdown strength and antiferroelectric stability, (Ag0.80Na0.20)(Nb0.80Ta0.20)O3 ceramic reveals a benign energy storage performance of Wrec = 5.8 J/cm3 and η = 61.7% with good temperature stability, frequency stability and cycling reliability. It is also found that the high applied electric field can promote the M2-M3 phase transition, which may provide ideas to improve the thermal stability of the energy storage performance in AgNbO3-based ceramics.