摘要
Lead-free bulk ceramics for advanced pulsed power capacitors show relatively low recoverable energy storage density(Wrec)especially at low electric field condition.To address this challenge,we propose an A-site defect engineering to optimize the electric polarization behavior by disrupting the orderly arrangement of A-site ions,in which Ba_(0.105)Na_(0.325)Sr_(0.245−1.5x)□_(0.5x)Bi_(0.325)+xTiO_(3)(BNS_(0.245−1.5x)□_(0.5x)B_(0.325+x)T,x=0,0.02,0.04,0.06,and 0.08)lead-free ceramics are selected as the representative.The BNS_(0.245−1.5x)□_(0.5x)B_(0.325+x)T ceramics are prepared by using pressureless solid-state sintering and achieve large W_(rec)(1.8 J/cm^(3))at a low electric field(@110 kV/cm)when x=0.06.The value of 1.8 J/cm3 is super high as compared to all other W_(rec) in lead-free bulk ceramics under a relatively low electric field(<160 kV/cm).Furthermore,a high dielectric constant of 2930 within 15%fluctuation in a wide temperature range of 40–350℃is also obtained in BNS_(0.245−1.5x)□_(0.5x)B_(0.325+x)T(x=0.06)ceramics.The excellent performances can be attributed to the A-site defect engineering,which can reduce remnant polarization(P_(r))and improve the thermal evolution of polar nanoregions(PNRs).This work confirms that the BNS_(0.245−1.5x)□_(0.5x)B_(0.325+x)T(x=0.06)ceramics are desirable for advanced pulsed power capacitors,and will push the development of a series of Bi0.5Na0.5TiO3(BNT)-based ceramics with high W_(rec) and high-temperature stability.
基金
This work was financially supported by the National Natural Science Foundation of China(No.51767010)
the Key Project of Natural Science Foundation of Jiangxi Province of China(No.20212ACB204010)。
