(1-x)NaNbO_(3-x)(0.3Bi_(0.5)Na_(0.5)TiO_(3)-0.7BiFeO_(3))陶瓷的介电以及储能性能研究

Dielectric and Energy Storage Properties of(1-x)NaNbO3-x(0.3Bi0.5Na0.5TiO3-0.7BiFeO3)Ceramics

采用常规固相法制备(1-x)NaNbO_(3-x)(0.3Bi_(0.5)Na_(0.5)TiO_(3)-0.7BiFeO_(3))[NN-x(BNT-BF)](x=0.05,0.1,0.15,0.2)陶瓷并对其物相组成、微观形貌、介电与储能特性进行系统研究.结果表明,随着BNT-BF含量的增加,NN-x(BNT-BF)陶瓷逐渐由正交反铁电P相和R相共存(x<0.1)转变为单一反铁电R相(x≥0.1),弛豫行为增强.BNT-BF掺杂显著改善了陶瓷的致密度,且陶瓷的平均晶粒尺寸随着掺杂量增大先减小后增大.同时取代NaNbO_(3)的A位和B位可破坏NN原有的铁电长程有序结构,优化陶瓷的储能性能.在410 kV/cm的击穿场强(Eb)下,NN-0.2(BNT-BF)陶瓷的有效储能密度(W_(rec))和储能效率(η)分别为2.54 J/cm^(3)和89.24%,且在20~120℃的温度范围内具有高的温度稳定性.同时,高功率密度(PD=49 MW/cm^(3))、大电流密度(CD=406 A/cm^(2))和超快放电速度(t0.9=35 ns)使得NN-0.2(BNT-BF)陶瓷在脉冲功率系统中具有潜在的应用前景.

Sodium niobate(NaNbO_(3))ceramic,as a representative of antiferroelectric materials,has been widely studied in the field of energy storage due to its environmental friendliness and non-toxicity.However,its application is greatly limited due to its square hysteresis loop,which leads to low recoverable energy storage density(Wrec).Introducing a second compo-nent into NaNbO_(3) to form a solid solution can enhance its energy storage properties.According to this train of thoughts,(1-x)NaNbO_(3-x)(0.3Bi_(0.5)Na_(0.5)TiO_(3)-0.7BiFeO_(3))[NN-x(BNT-BF)](x=0.05,0.1,0.15,0.2)ceramics were designed through substituting the A-and B-sites of NaNbO_(3) with Bi^(3+),Fe^(3+),and Ti4+simultaneously in this work.The NN-x(BNT-BF)ceram-ics were prepared by the conventional solid-state reaction method,and their phase compositions,microstructures,dielectric and energy storage properties were systematically investigated by X-ray diffraction(XRD),Raman spectrum,scanning elec-tron microscopy(SEM),dielectric property measurement and ferroelectric test.The results showed that with the increase of BNT-BF content,the phase composition of the NN-x(BNT-BF)ceramics gradually transformed from coexistence of orthogo-nal antiferroelectric P and R phases(x<0.1)to single antiferroelectric R phase(x≥0.1),and the relaxation behavior was significantly enhanced.The densification of the NN-x(BNT-BF)ceramics was remarkably improved.With the increase of BNT-BF content,the average grain size of the NN-x(BNT-BF)ceramics was firstly declined and then increased.Moreover,replacing the A-and B-sites of NaNbO_(3) by Bi^(3+),Fe^(3+),and Ti4+simultaneously could disrupt its original long-range antiferro-electric ordered structure,thus optimizing energy storage performances of the ceramics.At a high breakdown field strength(Eb)of 410 kV/cm,the NN-0.2(BNT-BF)ceramic achieved W_(rec) of 2.54 J/cm^(3),and energy storage efficiency(η)of 89.24%.In addition,the NN-0.2(BNT-BF)ceramic exhibited a high temperature stability in the temperature range of 20~120℃.Meanwhile,large power density(PD=49 MW/cm^(3)),high current density(CD=406 A/cm^(2)),and ultrafast discharge rate(t0.9=35 ns)made the NN-0.2(BNT-BF)ceramic have potential applications in pulse power systems.