摘要
Dielectric capacitors have been widely used in pulsed power devices owing to their ultrahigh power density,fast charge/discharge speed,and excellent stability.However,developing lead-free dielectric materials with a combination of high recoverable energy storage density and efficiency remains a challenge.Herein,a high energy storage density of 7.04 J/cm^(3) as well as a high efficiency of 80.5%is realized in the antiferroelectric Ag(Nb_(0.85)Ta_(0.15))O_(3)-modified BiFeO3-BaTiO3 ferroelectric ceramic.This achievement is mainly attributed to the combined effect of a high saturation polarization(Pmax),increased breakdown field(Eb),and reduction of the remnant polarization(Pr).The modification of pseudotetragonal BiFeO3 by Ag(Nb_(0.85)Ta_(0.15))O_(3) leads to a high Pmax,and the enhanced relaxor behavior gives rise to a small Pr.The promoted microstructure(such as a dense structure,fine grains,and compact grain boundaries)after modification results in a high breakdown strength.Furthermore,both the recoverable energy density and efficiency exhibit high stability over a broad range of operating frequencies(1–50 Hz)and working temperatures(25–120℃).These results suggest that the(0.67–x)BiFeO_(3)-0.33BaTiO_(3)-xAg(Nb_(0.85)Ta_(0.15))O_(3) ceramics can be highly competitive as a lead-free relaxor for energy storage applications.
基金
This work was supported by the Basic Science Center Project of NSFC no.52388201
Tsinghua University-Toyota Research Center.
