Lead-free relaxor ceramics(1−x)K_(0.5)Na_(0.5)NbO_(3)−xBi(Mn_(0.5)Ni_(0.5))O_(3)((1−x)KNN-xBMN)with considerable charge-discharge characteristics and energy storage properties were prepared by a solid state method.Rem...Lead-free relaxor ceramics(1−x)K_(0.5)Na_(0.5)NbO_(3)−xBi(Mn_(0.5)Ni_(0.5))O_(3)((1−x)KNN-xBMN)with considerable charge-discharge characteristics and energy storage properties were prepared by a solid state method.Remarkable,a BMN doping level of 0.04,0.96KNN-0.04BMN ceramic obtained good energy storage performance with acceptable energy storage density Wrec of 1.826 J/cm^(3) and energy storage efficiencyηof 77.4%,as well as good frequency stability(1-500 Hz)and fatigue resistance(1-5000 cycles).Meanwhile,a satisfactory charge-discharge performance with power density PD~98.90 MW/cm^(3),discharge time t0.9<70 ns and temperature stability(30-180°C)was obtained in 0.96KNN-0.04BMN ceramic.The small grain size(~150 nm)and the high polarizability of Bi3+are directly related to its good energy storage capacity.This work proposes a feasible approach for lead-free KNN-based ceramics to achieve high-energy storage and ultra-fast charge-discharge performance as well as candidate materials for the application of advanced high-temperature pulse capacitors.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
Ceramic-based dielectric capacitors are becoming more and more important in electronic devices.The ceramics of 0.93K_(0.5)Na_(0.5)NbO_(3)–0.07Bix(Mg_(1/3)Nb_(2/3))O_(3)(0.93KNN–0.07BixMN)(x?0:60,2/3,0.75 and 0.95)we...Ceramic-based dielectric capacitors are becoming more and more important in electronic devices.The ceramics of 0.93K_(0.5)Na_(0.5)NbO_(3)–0.07Bix(Mg_(1/3)Nb_(2/3))O_(3)(0.93KNN–0.07BixMN)(x?0:60,2/3,0.75 and 0.95)were successfully fabricated by virtue of the solid reaction process in this work.The results showed that the amount of Bi content has a significant impact on the ceramics of 0.93KNN–0.07BixMN.XRD indicates that all specimens exhibit a pure perovskite structure and existing oxygen vacancy in the specimens.The mean grain size for all specimens belong to submicron scale,and the sample of x=0.95 owns the smallest grain size is 0.11m.The maximum dielectric constant increases but the phase transition temperature Tm exhibits a contrary tendency at 1MHz with increasing Bi concentration.Besides,all ceramics are relaxor ferroelectric.The impedance analysis further revealed that the activation energy of the ceramics increases with Bi content.Eventually,the highestηof 58.8%and Wrec of 1.30 J/cm^(3) are simultaneously achieved in the sample with x=0.60.Overall,we demonstrate in this work that stoichiometry control of Bi in 0.93KNN–0.07BixMN ceramics is a practical method to obtain the desired structural,dielectric and energy storage properties.展开更多
基金supported by the National Natural Science Foundation of China(NSFC)(Grant No.52272119,51872177)the Natural Science Basic Research Plan in the Shaanxi Province of China(Grant No.2021ZDLSF06-03,2021JM-201)+1 种基金the Fundamental Research Funds for the Central Universities(Program No.GK202002014)the Fondamental Innovation Project in School of Materials Science and Engineering(SNNU).
文摘Lead-free relaxor ceramics(1−x)K_(0.5)Na_(0.5)NbO_(3)−xBi(Mn_(0.5)Ni_(0.5))O_(3)((1−x)KNN-xBMN)with considerable charge-discharge characteristics and energy storage properties were prepared by a solid state method.Remarkable,a BMN doping level of 0.04,0.96KNN-0.04BMN ceramic obtained good energy storage performance with acceptable energy storage density Wrec of 1.826 J/cm^(3) and energy storage efficiencyηof 77.4%,as well as good frequency stability(1-500 Hz)and fatigue resistance(1-5000 cycles).Meanwhile,a satisfactory charge-discharge performance with power density PD~98.90 MW/cm^(3),discharge time t0.9<70 ns and temperature stability(30-180°C)was obtained in 0.96KNN-0.04BMN ceramic.The small grain size(~150 nm)and the high polarizability of Bi3+are directly related to its good energy storage capacity.This work proposes a feasible approach for lead-free KNN-based ceramics to achieve high-energy storage and ultra-fast charge-discharge performance as well as candidate materials for the application of advanced high-temperature pulse capacitors.
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.
基金supported by National Science Foundation of China(Grant Nos.51572163,51577111 and 51607108)the Fundamental Research Funds for the Central Universities(Program Nos.GK201601003,GK201703016,GK201802007,201701011 and 2018CBLZ007).
文摘Ceramic-based dielectric capacitors are becoming more and more important in electronic devices.The ceramics of 0.93K_(0.5)Na_(0.5)NbO_(3)–0.07Bix(Mg_(1/3)Nb_(2/3))O_(3)(0.93KNN–0.07BixMN)(x?0:60,2/3,0.75 and 0.95)were successfully fabricated by virtue of the solid reaction process in this work.The results showed that the amount of Bi content has a significant impact on the ceramics of 0.93KNN–0.07BixMN.XRD indicates that all specimens exhibit a pure perovskite structure and existing oxygen vacancy in the specimens.The mean grain size for all specimens belong to submicron scale,and the sample of x=0.95 owns the smallest grain size is 0.11m.The maximum dielectric constant increases but the phase transition temperature Tm exhibits a contrary tendency at 1MHz with increasing Bi concentration.Besides,all ceramics are relaxor ferroelectric.The impedance analysis further revealed that the activation energy of the ceramics increases with Bi content.Eventually,the highestηof 58.8%and Wrec of 1.30 J/cm^(3) are simultaneously achieved in the sample with x=0.60.Overall,we demonstrate in this work that stoichiometry control of Bi in 0.93KNN–0.07BixMN ceramics is a practical method to obtain the desired structural,dielectric and energy storage properties.
