To reduce the coercive field of Na_(0.5)Bi_(0.5)TiO_(3),Ba TiO_(3)were added as dopant materials.Then the(1-x)Na_(0.5)Bi_(0.5)TiO_(3)-xBaTiO_(3)ceramic samples were produced in solid synthetic way.The optimum preparat...To reduce the coercive field of Na_(0.5)Bi_(0.5)TiO_(3),Ba TiO_(3)were added as dopant materials.Then the(1-x)Na_(0.5)Bi_(0.5)TiO_(3)-xBaTiO_(3)ceramic samples were produced in solid synthetic way.The optimum preparation condition and piezoelectric properties of the samples were investigated.The XRD results show that the fabric transites from rhombohedral to tetragonal gradually with the substitution of the Ba^(2+).The morphotropic phase boundaries(MPB)exists in the composition range of 0.06.展开更多
The increase in energy consumption and its collateral damage on the environment has encouraged the development of environment-friendly ceramic materials with good energy storage properties.In this work,(1-x)Na_(0.5)Bi...The increase in energy consumption and its collateral damage on the environment has encouraged the development of environment-friendly ceramic materials with good energy storage properties.In this work,(1-x)Na_(0.5)Bi_(0.5)TiO_(3)-xCa(Mg_(1/3)Nb_(2/3))O_(3) ceramics were synthesized by the solid-state reaction method.The 0.88Na_(0.5)Bi_(0.5)TiO_(3)-0.12Ca(Mg_(1/3)Nb_(2/3))O_(3) ceramic exhibited a high recoverable energy storage density of 8.1 J/cm3 and energy storage efficiency of 82.4% at 550 kV/cm.The introduction of Ca(Mg_(1/3)Nb_(2/3))O_(3) reduced the grain size and increased the band gap,thereby enhancing the breakdown field strength of the ceramic materials.The method also resulted in good temperature stability(20–140℃),frequency stability(1–200 Hz),and fatigue stability over 10^(6) cycles.In addition,an ultrahigh power density of 187 MW/cm^(3) and a fast charge-discharge rate(t_(0.9)=57.2 ns)can be obtained simultaneously.Finite element method analysis revealed that the decrease of grain size was beneficial to the increase of breakdown field strength.Therefore,the 0.88Na_(0.5)Bi_(0.5)TiO_(3)-0.12Ca(Mg_(1/3)Nb_(2/3))O_(3) ceramics resulted in high energy storage properties with good stability and were promising environment-friendly materials for advanced pulsed power systems applications.展开更多
The rapid development of high-power and pulsed-power techniques inspires extensive investigates on high-performance ceramic-based capacitors.However,the low recoverable energy density(Wrec)hampers their wider applicat...The rapid development of high-power and pulsed-power techniques inspires extensive investigates on high-performance ceramic-based capacitors.However,the low recoverable energy density(Wrec)hampers their wider applications.Herein,the non-stoichiometric Bi_(0.5)Na_(0.5)TiO_(3)-based ceramics were designed and studied.The proper introduction of oxygen vacancies facilitated activating defect dipole,giving rise to reduced remanent polarization.Consequently,the optimal composition exhibited an exceptional high Wrec of 8.3 J/cm^(3),a high efficiency of 85%,and excellent anti-fatigue and thermal reliability.This work provides an efficient approach to explore ceramic capacitors with high capacitive energy storage performances.展开更多
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
Lead-free(K_(0.5)Na_(0.5))NbO_(3)(KNN)and Li_(0.06)(K_(0.5)Na_(0.5))_(0.94)NbO_(3)(LKNN)thin films were fabricated by a sol-gel method.The effects of Li substitution on crystal structure,microstructure and electrical ...Lead-free(K_(0.5)Na_(0.5))NbO_(3)(KNN)and Li_(0.06)(K_(0.5)Na_(0.5))_(0.94)NbO_(3)(LKNN)thin films were fabricated by a sol-gel method.The effects of Li substitution on crystal structure,microstructure and electrical properties of KNN film were systematically studied.Li doping can enhance the ferroelectric and piezoelectric properties of KNN film.Compared with pure KNN film,the LKNN film possesses larger remanent polarization(P_(r)~9.3μC/cm^(2))and saturated polarization(P_(s)~41.2μC/cm^(2))and lower leakage current density(~10^(−5)A/cm^(2)at 200 kV/cm).Meanwhile,a typical butterfly shaped piezoelectric response curve is obtained in the LKNN film with a high piezoelectric coefficient(d_(33)~105 pm/V).Excellent fatigue resistance(~10^(9)switching cycles)and aging resistance(~180 days)demonstrate the long-term working stability of LKNN film.These findings indicate that KNN-based lead-free piezoelectric films have a broad application prospect in microelectromechanical systems(MEMS).展开更多
Next-generation advanced high/pulsed power capacitors urgently require dielectric materials with outstanding energy storage performance.Bi_(0.5)Na_(0.5)TiO_(3)-based lead-free materials exhibit high polarization,but t...Next-generation advanced high/pulsed power capacitors urgently require dielectric materials with outstanding energy storage performance.Bi_(0.5)Na_(0.5)TiO_(3)-based lead-free materials exhibit high polarization,but the high remanent polarization and large polarization hysteresis limit their applications in dielectric capacitors.Herein,high-entropy perovskite relaxor ferroelectrics(Na_(0.2)Bi_(0.2)Ba_(0.2)Sr_(0.2)Ca_(0.2))(Ti1-x%Zrx%)O_(3)are designed by adding multiple ions in the A-site and replacing the B-site Ti^(4+)with a certain amount of Zr^(4+).The newly designed system showed high relaxor feature and slim polarization-electric(P-E)loops.Especially,improved relaxor feature and obviously delayed polarization saturation were found with the increasing of Zr^(4+).Of particular importance is that both high recoverable energy storage density of 6.6 J/cm^(3) and energy efficiency of 93.5%were achieved under 550 kV/cm for the ceramics of x=6,accompanying with excellent frequency stability,appreciable thermal stability,and prosperous discharge property.This work not only provides potential dielectric materials for energy storage applications,but also offers an effective strategy to obtain dielectric ceramics with ultrahigh comprehensive energy storage performance to meet the demanding requirements of advanced energy storage applications.展开更多
(Bi_(0.5)Na_(0.5))TiO_(3)(BNT)-based lead-free piezoceramics exhibit excellent electric field-induced strain(electrostrain)properties,but often suffer from large hysteresis and poor fatigue resistance,which strongly l...(Bi_(0.5)Na_(0.5))TiO_(3)(BNT)-based lead-free piezoceramics exhibit excellent electric field-induced strain(electrostrain)properties,but often suffer from large hysteresis and poor fatigue resistance,which strongly limit their applications.Here,<00l>textured Nb5+-doped 0.8(Bi_(0.5)Na_(0.5))TiO_(3)–0.2(Bi_(0.5)K_(0.5))TiO_(3)(0.8BNT–0.2BKT)ceramics with a high degree of texturing(~80%)were prepared by the reactive template grain growth(RTGG)method using Bi4Ti3O12 as a template.By the combination of donor doping in the B-site and the RTGG method,the electrostrain performance achieves a significant enhancement.A high electrostrain of 0.65%and a piezoelectric coefficient(*33 d)of 1083 pm/V with reduced hysteresis at an electric field of 6 kV/mm are obtained.No electrostrain performance degradation is observed after unipolar electric field loading of 10^(5)cycles,showing excellent fatigue endurance.These results indicate that the texturing BNT-based lead-free piezoceramics by the RTGG method is a useful approach to developing eco-friendly actuators.展开更多
Dense(Na_(0.5)K_(0.5))NbO_(3)lead-free ceramics with the simple composition were prepared via sintering in low oxygen partial pressure(pO_(2),~10^(−12) atm)atmosphere and adding LiF.All the ceramics have pure orthorho...Dense(Na_(0.5)K_(0.5))NbO_(3)lead-free ceramics with the simple composition were prepared via sintering in low oxygen partial pressure(pO_(2),~10^(−12) atm)atmosphere and adding LiF.All the ceramics have pure orthorhombic structure.Compared to the LiF-added(Na_(0.5)K_(0.5))NbO_(3)ceramics sintered in air and the low pO_(2)-sintered pure(Na_(0.5)K_(0.5))NbO_(3)ceramics without LiF addition,the present ceramics exhibit improved piezoelectric and ferroelectric properties.The piezoelectric constant d33 is 125 pC/N,and the converse piezoelectric constant d_(33)^(*)is 186 pm/V.The dielectric constant and dielectric loss of the ceramics at room temperature and 1 kHz are 451 and 0.03,respectively.Under the measured electric field of 70 kV/cm,the remanent polarization is 25.9μC/cm^(2)and the coercive field is 13.9 kV/cm.Furthermore,if the base metals such as Cu and Ni powders were mixed into the green pellets and sintered in the low pO_(2)atmosphere,the base metals cannot be oxidized,suggesting possibility of using base metals as electrodes.展开更多
基金Funded by the National Natural Science Foundation of China (No.61704113)the Shenzhen Science and Technology Program (No.GJHZ20210705141805015)the Scientific Research Project in School-level (SZIIT2019KJ026)。
文摘To reduce the coercive field of Na_(0.5)Bi_(0.5)TiO_(3),Ba TiO_(3)were added as dopant materials.Then the(1-x)Na_(0.5)Bi_(0.5)TiO_(3)-xBaTiO_(3)ceramic samples were produced in solid synthetic way.The optimum preparation condition and piezoelectric properties of the samples were investigated.The XRD results show that the fabric transites from rhombohedral to tetragonal gradually with the substitution of the Ba^(2+).The morphotropic phase boundaries(MPB)exists in the composition range of 0.06.
基金This work is supported by the Natural Science Foundation of Shandong Province of China(Nos.ZR2020ME035,ZR2020QE043 and ZR2020QE044)National Natural Science Foundation of China(Nos.51872166 and 52102132)+1 种基金Postdoctoral Research Foundation of China(2017M622196)Opening Project of Key Laboratory of Inorganic Functional Materials and Devices,Chinese Academy of Sciences(KLIFMD201705).
文摘The increase in energy consumption and its collateral damage on the environment has encouraged the development of environment-friendly ceramic materials with good energy storage properties.In this work,(1-x)Na_(0.5)Bi_(0.5)TiO_(3)-xCa(Mg_(1/3)Nb_(2/3))O_(3) ceramics were synthesized by the solid-state reaction method.The 0.88Na_(0.5)Bi_(0.5)TiO_(3)-0.12Ca(Mg_(1/3)Nb_(2/3))O_(3) ceramic exhibited a high recoverable energy storage density of 8.1 J/cm3 and energy storage efficiency of 82.4% at 550 kV/cm.The introduction of Ca(Mg_(1/3)Nb_(2/3))O_(3) reduced the grain size and increased the band gap,thereby enhancing the breakdown field strength of the ceramic materials.The method also resulted in good temperature stability(20–140℃),frequency stability(1–200 Hz),and fatigue stability over 10^(6) cycles.In addition,an ultrahigh power density of 187 MW/cm^(3) and a fast charge-discharge rate(t_(0.9)=57.2 ns)can be obtained simultaneously.Finite element method analysis revealed that the decrease of grain size was beneficial to the increase of breakdown field strength.Therefore,the 0.88Na_(0.5)Bi_(0.5)TiO_(3)-0.12Ca(Mg_(1/3)Nb_(2/3))O_(3) ceramics resulted in high energy storage properties with good stability and were promising environment-friendly materials for advanced pulsed power systems applications.
基金supported by the National Natural Science Foundation of China(Nos.12004181,52073144)Natural Science Foundation of Jiangsu Province(Nos.BK20200473,BK20201301)the Fundamental Research Funds for the Central Universities(No.30922010309)。
文摘The rapid development of high-power and pulsed-power techniques inspires extensive investigates on high-performance ceramic-based capacitors.However,the low recoverable energy density(Wrec)hampers their wider applications.Herein,the non-stoichiometric Bi_(0.5)Na_(0.5)TiO_(3)-based ceramics were designed and studied.The proper introduction of oxygen vacancies facilitated activating defect dipole,giving rise to reduced remanent polarization.Consequently,the optimal composition exhibited an exceptional high Wrec of 8.3 J/cm^(3),a high efficiency of 85%,and excellent anti-fatigue and thermal reliability.This work provides an efficient approach to explore ceramic capacitors with high capacitive energy storage performances.
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supported by the National Natural Science Foundation of China(Grant Nos.51972144 and U1806221)the Taishan Scholars Program,the Case-by-Case Project for Top Outstanding Talents of Jinan,the Shandong Provincial Natural Science Foundation(Grant No.ZR2020KA003)+2 种基金the Primary Research&Development Plan of Shandong Province(Grant No.2019JZZY010313)the Project of“20 Items of University”of Jinan(Grant Nos.T202009 and T201907)the Introduction Program of Senior Foreign Experts(G2021024003L).
文摘Lead-free(K_(0.5)Na_(0.5))NbO_(3)(KNN)and Li_(0.06)(K_(0.5)Na_(0.5))_(0.94)NbO_(3)(LKNN)thin films were fabricated by a sol-gel method.The effects of Li substitution on crystal structure,microstructure and electrical properties of KNN film were systematically studied.Li doping can enhance the ferroelectric and piezoelectric properties of KNN film.Compared with pure KNN film,the LKNN film possesses larger remanent polarization(P_(r)~9.3μC/cm^(2))and saturated polarization(P_(s)~41.2μC/cm^(2))and lower leakage current density(~10^(−5)A/cm^(2)at 200 kV/cm).Meanwhile,a typical butterfly shaped piezoelectric response curve is obtained in the LKNN film with a high piezoelectric coefficient(d_(33)~105 pm/V).Excellent fatigue resistance(~10^(9)switching cycles)and aging resistance(~180 days)demonstrate the long-term working stability of LKNN film.These findings indicate that KNN-based lead-free piezoelectric films have a broad application prospect in microelectromechanical systems(MEMS).
基金This work was financially supported by the Guangxi Natural Science Fund for Distinguished Young Scholars(Grant No.2022GXNSFFA035034)National Natural Science Foundation of China(Grant Nos.52072080 and U22A20127)National Key R&D Program of China(Grant No.2022YFC2408600).We also would like to acknowledge the support from Xiaomi Foundation/Xiaomi Young Talents Program.
文摘Next-generation advanced high/pulsed power capacitors urgently require dielectric materials with outstanding energy storage performance.Bi_(0.5)Na_(0.5)TiO_(3)-based lead-free materials exhibit high polarization,but the high remanent polarization and large polarization hysteresis limit their applications in dielectric capacitors.Herein,high-entropy perovskite relaxor ferroelectrics(Na_(0.2)Bi_(0.2)Ba_(0.2)Sr_(0.2)Ca_(0.2))(Ti1-x%Zrx%)O_(3)are designed by adding multiple ions in the A-site and replacing the B-site Ti^(4+)with a certain amount of Zr^(4+).The newly designed system showed high relaxor feature and slim polarization-electric(P-E)loops.Especially,improved relaxor feature and obviously delayed polarization saturation were found with the increasing of Zr^(4+).Of particular importance is that both high recoverable energy storage density of 6.6 J/cm^(3) and energy efficiency of 93.5%were achieved under 550 kV/cm for the ceramics of x=6,accompanying with excellent frequency stability,appreciable thermal stability,and prosperous discharge property.This work not only provides potential dielectric materials for energy storage applications,but also offers an effective strategy to obtain dielectric ceramics with ultrahigh comprehensive energy storage performance to meet the demanding requirements of advanced energy storage applications.
基金supported by the National Natural Science Foundation of China(52172135)the Youth Top Talent Project of the National“Ten Thousand Talents Program”(2021-527-07)the Guangdong Basic and Applied Basic Research Foundation for Distinguished Young Scholars(2021B1515020083 and 2022B1515020070).
文摘(Bi_(0.5)Na_(0.5))TiO_(3)(BNT)-based lead-free piezoceramics exhibit excellent electric field-induced strain(electrostrain)properties,but often suffer from large hysteresis and poor fatigue resistance,which strongly limit their applications.Here,<00l>textured Nb5+-doped 0.8(Bi_(0.5)Na_(0.5))TiO_(3)–0.2(Bi_(0.5)K_(0.5))TiO_(3)(0.8BNT–0.2BKT)ceramics with a high degree of texturing(~80%)were prepared by the reactive template grain growth(RTGG)method using Bi4Ti3O12 as a template.By the combination of donor doping in the B-site and the RTGG method,the electrostrain performance achieves a significant enhancement.A high electrostrain of 0.65%and a piezoelectric coefficient(*33 d)of 1083 pm/V with reduced hysteresis at an electric field of 6 kV/mm are obtained.No electrostrain performance degradation is observed after unipolar electric field loading of 10^(5)cycles,showing excellent fatigue endurance.These results indicate that the texturing BNT-based lead-free piezoceramics by the RTGG method is a useful approach to developing eco-friendly actuators.
基金This work was supported by National Natural Science Foundation of China(No.51972202)Fundamental Research Funds for the Central Universities(No.GK201901005,2019CSLY006).
文摘Dense(Na_(0.5)K_(0.5))NbO_(3)lead-free ceramics with the simple composition were prepared via sintering in low oxygen partial pressure(pO_(2),~10^(−12) atm)atmosphere and adding LiF.All the ceramics have pure orthorhombic structure.Compared to the LiF-added(Na_(0.5)K_(0.5))NbO_(3)ceramics sintered in air and the low pO_(2)-sintered pure(Na_(0.5)K_(0.5))NbO_(3)ceramics without LiF addition,the present ceramics exhibit improved piezoelectric and ferroelectric properties.The piezoelectric constant d33 is 125 pC/N,and the converse piezoelectric constant d_(33)^(*)is 186 pm/V.The dielectric constant and dielectric loss of the ceramics at room temperature and 1 kHz are 451 and 0.03,respectively.Under the measured electric field of 70 kV/cm,the remanent polarization is 25.9μC/cm^(2)and the coercive field is 13.9 kV/cm.Furthermore,if the base metals such as Cu and Ni powders were mixed into the green pellets and sintered in the low pO_(2)atmosphere,the base metals cannot be oxidized,suggesting possibility of using base metals as electrodes.
