Lead-free(Na_(0.5)Bi_(0.5))TiO_(3)-based dielectric materials are promising for electrostatic energy storage due to their strong polarization response and environmental friendliness.However,challenges like high electr...Lead-free(Na_(0.5)Bi_(0.5))TiO_(3)-based dielectric materials are promising for electrostatic energy storage due to their strong polarization response and environmental friendliness.However,challenges like high electric hysteresis loss(W_(loss))and low electric breakdown strength(Eb)limit their recoverable energy density(W_(rec))and energy conversion efficiency(η).A superparaelectric design with structure optimization has been proposed to overcome these restrictions.Based on this strategy,a series of(1-x)(Na_(0.3)Bi_(0.3)8Sr_(0.28))TiO3-xCa(Ta_(0.2)Ti_(0.75))O_(3)(abbreviated as(1-x)NBST-xCTT;x=0.0,0.1,0.2,0.3,and 0.4)ceramics were fabricated.Their phase structure gradually evolves from the rhombohedral and tetragonal coexistence(R&T)to the tetragonal and cubic coexistence(T&C),accompanied by the increasing proportion of weakly coupled and highly dynamic polar structures.This behavior enables the establishment of a superparaelectric relaxor ferroelectric(SPE-RFE)state,reducing Wloss,enhancingη,and improving dielectric stability.The improved microstructure with refined grains boosted Eb,further contributing to excellent performances.Notably,the optimized 0.6NBST-0.4CTT SPE-RFE ceramic,with high Eb,large polarization difference(ΔP),and slight Wloss,delivered a large Wrec of 6.90 J cm^(-3)with a highηof 92.55%at 600 kV cm^(-1),alongside excellent dielectric stability(-60 to 135℃)following the EIA-X7R standard.Moreover,a high power density(-125 MW cm^(-3))and an ultrafast charge-discharge rate(t_(0.9)∼33 ns)were realized at 300 kV cm-1.Encouragingly,the 0.6NBST-0.4CTT SPE-RFE ceramic also exhibits excellent energy-storage/charge-discharge stabilities.These results highlight the promising potential of the 0.6NBST-0.4CTT SPE-RFE ceramic for electrostatic energy storage.They also confirm the effectiveness of this strategy and provide valuable guidance for advancing dielectric energy-storage materials/capacitors.展开更多
Dielectric capacitors with high energy storage performances are exceedingly desired for the nextgeneration advanced high/pulsed power devices that demand miniaturization and integration.However,poor energy-storage den...Dielectric capacitors with high energy storage performances are exceedingly desired for the nextgeneration advanced high/pulsed power devices that demand miniaturization and integration.However,poor energy-storage density(U_(rec))and low efficiency(η)resulted from the large remanent polarization(P_(r))and low breakdown strength(BDS),have been the major challenge for the application of dielectric capacitors.Herein,a high-entropy strategy with superparaelectric relaxor ferroelectrics(SPRFE)was adopted to achieve extremely low Pr and high BDS in BaTiO_(3)system,simultaneously.Due to the high BDS~800 kV/cm and low Pr~0.58 mC/cm^(2),high-entropy SP-RFE(La_(0.05)Ba_(0.18)Sr_(0.18)K_(0.115)Na_(0.115)-Ca_(0.18)Bi_(0.18))TiO_(3)(LBSKNCBT)MLCCs exhibited high Urec~6.63 J/cm^(3)and excellent h~96%.What's more,LBSKNCBT MLCCs with high-entropy and SP-RFE characteristic also possess a good temperature and frequency stability.In a word,this work offers an excellent paradigm for achieving good energy-storage properties of BaTiO_(3)-based dielectric capacitors to meet the demanding requirements of advanced energy storage applications.展开更多
To meet the expectation set by Moore’s law on transistors,the search for thickness-scalable high dielectric constant(k)gate layers has become an emergent research frontier.Previous investigations have failed to solve...To meet the expectation set by Moore’s law on transistors,the search for thickness-scalable high dielectric constant(k)gate layers has become an emergent research frontier.Previous investigations have failed to solve the“polarizability–scalability–insulation robustness”trilemma.In this work,we show that this trilemma can be solved by using a gate layer of a high k ferroelectric oxide in its superparaelectric(SPE)state.In the SPE,its polar order becomes local and is dispersed in an amorphous matrix with a crystalline size down to a few nanometers,leading to an excellent dimensional scalability and a good field-stability of the k value.As an example,a stable high k value(37±3)is shown in ultrathin SPE films of(Ba_(0.95),Sr_(0.05))(Zr_(0.2),Ti_(0.8))O_(3)deposited on LaNiO_(3)-buffered Pt/Ti/SiO_(2)/(100)Si down to a 4 nm thickness,leading to a small equivalent oxide thickness of~0.46 nm.The aforementioned characteristic microstructure endows the SPE film a high breakdown strength(~10.5 MV·cm^(−1)for the 4 nm film),and hence ensures a low leakage current for the operation of the complementary metal oxide semiconductor(CMOS)gate.Lastly,a high electrical fatigue resistance is displayed by the SPE films.These results reveal a great potential of superparaelectric materials as gate dielectrics in the next-generation microelectronics.展开更多
The development of ceramic capacitors featuring high reliability and superior comprehensive performance is vital for practical applications in medium electric fields.In this work,a synergistic strategy was proposed to...The development of ceramic capacitors featuring high reliability and superior comprehensive performance is vital for practical applications in medium electric fields.In this work,a synergistic strategy was proposed to improve the energy storage performance of(1−x)0.94Bi_(0.47)Na_(0.47)Ba_(0.06)TiO_(3)-0.25CaTi_(0.8)Sn_(0.2)O_(3)((1−x)BNBT-xCTS)ceramics by introducing polymorphic nanodomains and transforming rhombohedral(R3c)to tetragonal(P4bm)forms,exhibiting a superparaelectric state at room temperature(RT).展开更多
The dielectric ceramic capacitor serves as the core energy storage element in the pulsed power system.However,the inability to balance high energy storage density(W_(rec))and energy storage efficiency(η)has become a ...The dielectric ceramic capacitor serves as the core energy storage element in the pulsed power system.However,the inability to balance high energy storage density(W_(rec))and energy storage efficiency(η)has become a technical challenge limiting the miniaturisation of pulsed power devices.This work proposes an entropy-driven strategy,through introducing Sr(Sc0.5Nb0.5)O_(3)(SSN)as an end-member,to modulate the phase structure and suppress interfacial polarization in the medium entropy matrix,(Bi_(0.5)Na_(0.5))_(0.5)Ba_(0.5)TiO_(3)(BN50BT).The introduction of SSN endows BN50BT ceramics with a multiphase structure of P4mm and Pm m and successfully establishes a super-paraelectric(SPE)state at room temperature,improving the polarization response.Furthermore,the incorporation of SSN effectively suppresses interfacial polarization and enhances the Eb of the system.Thus,the 0.80[(Bi_(0.5)Na_(0.5))_(0.5)Ba_(0.5)TiO_(3)]-0.20Sr(Sc_(0.5)Nb_(0.5))O_(3) ceramics exhibit a decent W_(rec) of 6.24 J/cm^(3) and a highηof 89.02%,along with remarkable stabilities over a wide frequency range(5-150 Hz)and temperature range(25-140℃).This work demonstrates that the entropy-driven construction of a multiphase-coexisting SPE state,along with suppressed interfacial polarization,represents a feasible approach to optimizing the energy storage properties of dielectric ceramics.展开更多
文摘Lead-free(Na_(0.5)Bi_(0.5))TiO_(3)-based dielectric materials are promising for electrostatic energy storage due to their strong polarization response and environmental friendliness.However,challenges like high electric hysteresis loss(W_(loss))and low electric breakdown strength(Eb)limit their recoverable energy density(W_(rec))and energy conversion efficiency(η).A superparaelectric design with structure optimization has been proposed to overcome these restrictions.Based on this strategy,a series of(1-x)(Na_(0.3)Bi_(0.3)8Sr_(0.28))TiO3-xCa(Ta_(0.2)Ti_(0.75))O_(3)(abbreviated as(1-x)NBST-xCTT;x=0.0,0.1,0.2,0.3,and 0.4)ceramics were fabricated.Their phase structure gradually evolves from the rhombohedral and tetragonal coexistence(R&T)to the tetragonal and cubic coexistence(T&C),accompanied by the increasing proportion of weakly coupled and highly dynamic polar structures.This behavior enables the establishment of a superparaelectric relaxor ferroelectric(SPE-RFE)state,reducing Wloss,enhancingη,and improving dielectric stability.The improved microstructure with refined grains boosted Eb,further contributing to excellent performances.Notably,the optimized 0.6NBST-0.4CTT SPE-RFE ceramic,with high Eb,large polarization difference(ΔP),and slight Wloss,delivered a large Wrec of 6.90 J cm^(-3)with a highηof 92.55%at 600 kV cm^(-1),alongside excellent dielectric stability(-60 to 135℃)following the EIA-X7R standard.Moreover,a high power density(-125 MW cm^(-3))and an ultrafast charge-discharge rate(t_(0.9)∼33 ns)were realized at 300 kV cm-1.Encouragingly,the 0.6NBST-0.4CTT SPE-RFE ceramic also exhibits excellent energy-storage/charge-discharge stabilities.These results highlight the promising potential of the 0.6NBST-0.4CTT SPE-RFE ceramic for electrostatic energy storage.They also confirm the effectiveness of this strategy and provide valuable guidance for advancing dielectric energy-storage materials/capacitors.
基金supported by National Natural Science Foundation of China(No.52272104)Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities)(No.FRF-IDRY-21-002).
文摘Dielectric capacitors with high energy storage performances are exceedingly desired for the nextgeneration advanced high/pulsed power devices that demand miniaturization and integration.However,poor energy-storage density(U_(rec))and low efficiency(η)resulted from the large remanent polarization(P_(r))and low breakdown strength(BDS),have been the major challenge for the application of dielectric capacitors.Herein,a high-entropy strategy with superparaelectric relaxor ferroelectrics(SPRFE)was adopted to achieve extremely low Pr and high BDS in BaTiO_(3)system,simultaneously.Due to the high BDS~800 kV/cm and low Pr~0.58 mC/cm^(2),high-entropy SP-RFE(La_(0.05)Ba_(0.18)Sr_(0.18)K_(0.115)Na_(0.115)-Ca_(0.18)Bi_(0.18))TiO_(3)(LBSKNCBT)MLCCs exhibited high Urec~6.63 J/cm^(3)and excellent h~96%.What's more,LBSKNCBT MLCCs with high-entropy and SP-RFE characteristic also possess a good temperature and frequency stability.In a word,this work offers an excellent paradigm for achieving good energy-storage properties of BaTiO_(3)-based dielectric capacitors to meet the demanding requirements of advanced energy storage applications.
基金the National Natural Science Foundation of China(Nos.51772175 and 52002192)the Natural Science Foundation of Shandong Province(Nos.ZR2022ZD39,ZR2020QE042,ZR2022ME031,and ZR2022QB138)+2 种基金the Science,Education and Industry Integration Pilot Projects of Qilu University of Technology(Shandong Academy of Sciences)(Nos.2022GH018 and 2022PY055)Jun Ouyang acknowledges the support from the Jinan City Science and Technology Bureau(No.2021GXRC055)the Education Department of Hunan Province/Xiangtan University(No.KZ0807969).
文摘To meet the expectation set by Moore’s law on transistors,the search for thickness-scalable high dielectric constant(k)gate layers has become an emergent research frontier.Previous investigations have failed to solve the“polarizability–scalability–insulation robustness”trilemma.In this work,we show that this trilemma can be solved by using a gate layer of a high k ferroelectric oxide in its superparaelectric(SPE)state.In the SPE,its polar order becomes local and is dispersed in an amorphous matrix with a crystalline size down to a few nanometers,leading to an excellent dimensional scalability and a good field-stability of the k value.As an example,a stable high k value(37±3)is shown in ultrathin SPE films of(Ba_(0.95),Sr_(0.05))(Zr_(0.2),Ti_(0.8))O_(3)deposited on LaNiO_(3)-buffered Pt/Ti/SiO_(2)/(100)Si down to a 4 nm thickness,leading to a small equivalent oxide thickness of~0.46 nm.The aforementioned characteristic microstructure endows the SPE film a high breakdown strength(~10.5 MV·cm^(−1)for the 4 nm film),and hence ensures a low leakage current for the operation of the complementary metal oxide semiconductor(CMOS)gate.Lastly,a high electrical fatigue resistance is displayed by the SPE films.These results reveal a great potential of superparaelectric materials as gate dielectrics in the next-generation microelectronics.
基金supported by the National Natural Science Foundation of China(No.U21A2074 and 52072381)Tianjin Science and Technology Plan Program(Grant No.19ZYPTJC00070).
文摘The development of ceramic capacitors featuring high reliability and superior comprehensive performance is vital for practical applications in medium electric fields.In this work,a synergistic strategy was proposed to improve the energy storage performance of(1−x)0.94Bi_(0.47)Na_(0.47)Ba_(0.06)TiO_(3)-0.25CaTi_(0.8)Sn_(0.2)O_(3)((1−x)BNBT-xCTS)ceramics by introducing polymorphic nanodomains and transforming rhombohedral(R3c)to tetragonal(P4bm)forms,exhibiting a superparaelectric state at room temperature(RT).
基金supported by Guangxi Science and Technology Plan Project(GuikeAD25069100)Guangxi Natural Science Foundation Project(2025GXNSFBA069167).
文摘The dielectric ceramic capacitor serves as the core energy storage element in the pulsed power system.However,the inability to balance high energy storage density(W_(rec))and energy storage efficiency(η)has become a technical challenge limiting the miniaturisation of pulsed power devices.This work proposes an entropy-driven strategy,through introducing Sr(Sc0.5Nb0.5)O_(3)(SSN)as an end-member,to modulate the phase structure and suppress interfacial polarization in the medium entropy matrix,(Bi_(0.5)Na_(0.5))_(0.5)Ba_(0.5)TiO_(3)(BN50BT).The introduction of SSN endows BN50BT ceramics with a multiphase structure of P4mm and Pm m and successfully establishes a super-paraelectric(SPE)state at room temperature,improving the polarization response.Furthermore,the incorporation of SSN effectively suppresses interfacial polarization and enhances the Eb of the system.Thus,the 0.80[(Bi_(0.5)Na_(0.5))_(0.5)Ba_(0.5)TiO_(3)]-0.20Sr(Sc_(0.5)Nb_(0.5))O_(3) ceramics exhibit a decent W_(rec) of 6.24 J/cm^(3) and a highηof 89.02%,along with remarkable stabilities over a wide frequency range(5-150 Hz)and temperature range(25-140℃).This work demonstrates that the entropy-driven construction of a multiphase-coexisting SPE state,along with suppressed interfacial polarization,represents a feasible approach to optimizing the energy storage properties of dielectric ceramics.
