With the increasing demand of high-power and pulsed power electronic devices,environmental-friendly potassium sodium niobate((Na_(0.5)K_(0.5))NbO_(3),KNN)ceramic-based capacitors have attracted much attention in recen...With the increasing demand of high-power and pulsed power electronic devices,environmental-friendly potassium sodium niobate((Na_(0.5)K_(0.5))NbO_(3),KNN)ceramic-based capacitors have attracted much attention in recent years owning to the boosted energy storage density(W_(rec)).Nevertheless,the dielectric loss also increases as the external electric field increases,which will generate much dissipated energy and raise the temperature of ceramic capacitors.Thus,an effective strategy is proposed to enhance the energy storage efficiency(η)via tailoring relaxor behavior and bad gap energy in the ferroelectric 0.9(Na_(0.5)K_(0.5))-NbO_(3)-0.1Bi(Zn_(2/3)(Nb_(x)Ta_(1−x))1/3)O_(3) ceramics.On the one hand,the more diverse ions in the B-sites owing to introducing the Ta could further disturb the long-range ferroelectric polar order to form the short−range polar nanoregions(PNRs),resulting in the highη.On the other hand,the introduction of Ta ions could boost the intrinsic band energy gap and thus improve the Eb.As a result,high Wrec of 3.29 J/cm^(3) and ultrahighηof 90.1%at the high external electric field of 310 kV/cm are achieved in x=0.5 sample.These results reveal that the KNN-based ceramics are promising lead-free candidate for high-power electronic devices.展开更多
Designing dielectric materials with the tremendous energy storage density is fundamentally important for developing pulse power capacitors.An effective approach was proposed to favorably modify the dielectric energy s...Designing dielectric materials with the tremendous energy storage density is fundamentally important for developing pulse power capacitors.An effective approach was proposed to favorably modify the dielectric energy storage properties(ESP)of Bi_(0.5)Na_(0.5)TiO_(3) ceramics using CaTiO_(3) incorporation.The dielectric breakdown strength was effectively enhanced,and simultaneously the relaxor behavior was optimized to lower the remnant polarization,which is resulted from the decreased grains size with the introduction of Ca^(2+)ion.Remarkably,at a CaTiO_(3) doping level of 0.2,a 0.8Bi_(0.5)Na_(0.5)TiO_(3)-0.2CaTiO_(3)(0.8BNT-0.2CT)ceramic obtained both high energy storage density(Wtotal)of~1.38 J/cm^(3) together with excellent efficiency(h)of~91.3%.Furthermore,an ultrafast discharge response speed(t0:9)~94 ns was achieved in 0.8BNT-0.2CT ceramic,as well as tremendous current density(C_(D)~1520 A/cm2)and power density(P_(D)~115 MW/cm^(3)).This study not only revealed the superior ESP mechanism as regards Bi_(0.5)Na_(0.5)TiO_(3) based ceramics but also provided candidate materials in pulse power capacitor devices.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52072150)the Young Elite Scientists Sponsorship Program of the Chinese Academy of Space Technology(CAST)and Open Foundation of Guangdong Provincial Key Laboratory of Electronic Functional Materials and Devices(EFMD2021002Z).
文摘With the increasing demand of high-power and pulsed power electronic devices,environmental-friendly potassium sodium niobate((Na_(0.5)K_(0.5))NbO_(3),KNN)ceramic-based capacitors have attracted much attention in recent years owning to the boosted energy storage density(W_(rec)).Nevertheless,the dielectric loss also increases as the external electric field increases,which will generate much dissipated energy and raise the temperature of ceramic capacitors.Thus,an effective strategy is proposed to enhance the energy storage efficiency(η)via tailoring relaxor behavior and bad gap energy in the ferroelectric 0.9(Na_(0.5)K_(0.5))-NbO_(3)-0.1Bi(Zn_(2/3)(Nb_(x)Ta_(1−x))1/3)O_(3) ceramics.On the one hand,the more diverse ions in the B-sites owing to introducing the Ta could further disturb the long-range ferroelectric polar order to form the short−range polar nanoregions(PNRs),resulting in the highη.On the other hand,the introduction of Ta ions could boost the intrinsic band energy gap and thus improve the Eb.As a result,high Wrec of 3.29 J/cm^(3) and ultrahighηof 90.1%at the high external electric field of 310 kV/cm are achieved in x=0.5 sample.These results reveal that the KNN-based ceramics are promising lead-free candidate for high-power electronic devices.
基金This work was supported by the National Natural Science Foundation of China(Grant NO 51872177)The authors would also like to thank the Natural Science Basic Research Plan in the Shaanxi Province of China(Grant No.2022JQ-338,2021ZDLSF06-03,2021JM-201)+1 种基金Science and Technology Project of Xian,China(Grant No.2020KJRC0014)the Fundamental Research Funds for the Central Universities(Program No.GK202002014).
文摘Designing dielectric materials with the tremendous energy storage density is fundamentally important for developing pulse power capacitors.An effective approach was proposed to favorably modify the dielectric energy storage properties(ESP)of Bi_(0.5)Na_(0.5)TiO_(3) ceramics using CaTiO_(3) incorporation.The dielectric breakdown strength was effectively enhanced,and simultaneously the relaxor behavior was optimized to lower the remnant polarization,which is resulted from the decreased grains size with the introduction of Ca^(2+)ion.Remarkably,at a CaTiO_(3) doping level of 0.2,a 0.8Bi_(0.5)Na_(0.5)TiO_(3)-0.2CaTiO_(3)(0.8BNT-0.2CT)ceramic obtained both high energy storage density(Wtotal)of~1.38 J/cm^(3) together with excellent efficiency(h)of~91.3%.Furthermore,an ultrafast discharge response speed(t0:9)~94 ns was achieved in 0.8BNT-0.2CT ceramic,as well as tremendous current density(C_(D)~1520 A/cm2)and power density(P_(D)~115 MW/cm^(3)).This study not only revealed the superior ESP mechanism as regards Bi_(0.5)Na_(0.5)TiO_(3) based ceramics but also provided candidate materials in pulse power capacitor devices.
