Energy storage properties of sodium niobate based antiferroelectric ceramics doped with 0.94(Bi0.5Na0.5TiO3)-0.06BaTiO3
Bi3+and Ba2+was used to replace Na+at the A-site,and Ti4+was used to replace Nb5+at the B-site to enhance the relaxor properties of NaNbO3-based ceramics,resulting in lower remnant polarization and improved energy storage characteristics. Additionally,the orbital hybridization between Bi3+6s and O2-2p,as well as the introduction of highly polarizable Ba2+,contributes to achieving higher maximum polarization. Based on this,combined with viscous polymer rolling process (VPRP),the composition of (1-x)NaNbO3-x[0.94(Bi0.5Na0.5TiO3)-0.06BaTiO3](NN-x(BNT-BT),x=0.20,0.25,0.30 and 0.35) was designed and dense thick film ceramics were prepared at 1140 ℃ to 1160 ℃ for 2 h. The results show that with an increase in BNT-BT doping content,the breakdown strength of NN-x(BNT-BT) ceramics can be significantly improved. Under an applied electric field of 550 kV·cm-1,the NN-0.35(BNT-BT) ceramic exhibits optimal energy storage performance with energy density of 6.7 J·cm-3 and energy efficiency of 79.67%. Under an electric field of 300 kV·cm-1 and temperature range of 25-120 ℃,the NN-0.35(BNT-BT) ceramic shows good temperature stability,with variations in energy density and efficiency of 9% and 7%,respectively. Meanwhile,within a frequency range of 10-500 Hz,the variations in energy density and efficiency are 3% and 5%,respectively,demonstrating excellent frequency stability. Furthermore,the NN-0.35(BNT-BT) ceramic possesses high power density (261.014 MW·cm-3) and fast discharge time (19 ns),indicating great potential for application in the pulse capacitors field.