How to achieve synergistic improvement of permittivity(ε_(r))and breakdown strength(E_(b))is a huge challenge for polymer dielectrics.Here,for the first time,theπ-conjugated comonomer(MHT)can simultaneously promote ...How to achieve synergistic improvement of permittivity(ε_(r))and breakdown strength(E_(b))is a huge challenge for polymer dielectrics.Here,for the first time,theπ-conjugated comonomer(MHT)can simultaneously promote theε_(r)and E_(b)of linear poly(methyl methacrylate)(PMMA)copolymers.The PMMA-based random copolymer films(P(MMA-co-MHT)),block copolymer films(PMMA-b-PMHT),and PMMA-based blend films were prepared to investigate the effects of sequential structure,phase separation structure,and modification method on dielectric and energy storage properties of PMMA-based dielectric films.As a result,the random copolymer P(MMA-coMHT)can achieve a maximumε_(r)of 5.8 at 1 kHz owing to the enhanced orientation polarization and electron polarization.Because electron injection and charge transfer are limited by the strong electrostatic attraction ofπ-conjugated benzophenanthrene group analyzed by the density functional theory(DFT),the discharge energy density value of P(MMA-co-PMHT)containing 1 mol%MHT units with the efficiency of 80%reaches15.00 J cm^(-3)at 872 MV m^(-1),which is 165%higher than that of pure PMMA.This study provides a simple and effective way to fabricate the high performance of polymer dielectrics via copolymerization with the monomer of P-type semi-conductive polymer.展开更多
Ensuring reliable and safe operation of high-power electronic devices necessitates the development of high-quality dielectric nano-capacitors with high recoverable energy density(URec)and efficiency(η)at low applied ...Ensuring reliable and safe operation of high-power electronic devices necessitates the development of high-quality dielectric nano-capacitors with high recoverable energy density(URec)and efficiency(η)at low applied electric fields(E)/voltages.In this work,we demonstrate ultra-high URec andηat low E<500 kV/cm in as-grown epitaxial relaxor ferroelectric(RFE)PMN-33PT films,rivaling those typically achieved in state-of-the-art RFE and antiferroelectric(AFE)materials.The high energy storage properties were achieved using a synergistic strategy involving large polarization,a giant built-in potential/imprint(five times higher than the coercive field),and AFE like behavior.The structural,chemical,and electrical investigations revealed that these achievements mainly arise from the effects of strain,dipole defects,and chemical composition.For instance,at low E,the capacitors exhibit under 160 kV/cm(i.e.,8 V)and 400 kV/cm(i.e.,20 V),respectively,an ultra-highΔP(45μC/cm^(2)and 60μC/cm^(2)),UE=URec/E(21 J·MV/cm^(2)and 17 J·MV/cm^(2)),and UF=URec/(1-η)(20 J/cm^(3)and 47 J/cm^(3))with a robust charge-discharge fatigue endurance and outstanding frequency and thermal stability.Additionally,the designed films exhibit outstanding energy storage performance at higher E up to 2 MV/cm(ΔP≈78μC/cm^(2),UE≈17.3 J·MV/cm^(2)and UF≈288 J/cm^(3))due to their low leakage current density.展开更多
Antiferroelectric(AFE)ceramic materials with excellent temperature stability are critical for meeting ever-increasing demands for practical energy storage applications.However,how to remain high dielectric breakdown s...Antiferroelectric(AFE)ceramic materials with excellent temperature stability are critical for meeting ever-increasing demands for practical energy storage applications.However,how to remain high dielectric breakdown strategy at high temperature,at the same time to keep energy storage density(W_(rec))with high energy storage efficiency(η)is still a major challenge.In this work,polyurethane-Cu(PU-Cu)was introduced into a(Pb_(0.64)Tm_(0.04)La_(0.2))(Zr_(0.55)Sn_(0.44)Ti_(0.01))(PTL2ZST)AFE thick film to enhance the energy storage performance at high temperatures.PTL2ZST dispersed in PU-Cu because PU-Cu functions by introducing carrier traps,reducing conduction and leakage currents at high temperatures.As a result,at a working temperature of 140℃,its W_(rec)andηremain within the range of±5%compared with those of pure PTL2ZST(W_(rec)decreases by 21.7%,ηincreases by 9.4%at 100℃).Furthermore,ultrahigh W_(rec)of 17.01 J/cm^(3)withηof 80.31%in PTL2ZST-90%PU-Cu thick films at 2500 kV/cm at room temperature(RT)was obtained.Moreover,this study has outstanding filtering performance because the high degree of insulation caused by carrier traps weakens the charge carrier transport.In the rectifier circuit,the PTL2ZST-90%PU-Cu films can filter off 90%of the clutter.This study provides a feasible method to produce high-performance dielectric materials because of their high energy storage performance and heat resistance,which also broadens the field of filter application.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
Combining layers with high breakdown resistance and high polarization is a promising approach for designing dielectric capacitors with high energy density and efficiency.However,such combinations often accompany stron...Combining layers with high breakdown resistance and high polarization is a promising approach for designing dielectric capacitors with high energy density and efficiency.However,such combinations often accompany strong interfacial polarization,magnification of local electric fields,leading to premature breakdown.This work addresses this issue via controlled formation of diffusospheres.We constructed multilayer heterogeneous films using two Bi_(0.5)Na_(0.5)TiO_(3)(BNT)-based substances with high breakdown resistance and high polarization properties.Experimental results and finite element simulations demonstrate that the energy storage capacity of these films effectively harnesses the advantages of both phases.Notably,the interface polarization is minimal.Instead,a solid solution-like diffusosphere,formed by the mutual diffusion of ions between the two phases,plays a crucial role.The diffusosphere acts as a transition zone,mitigating charge aggregation at the interfaces and optimizing the relaxor and breakdown characteristics of the capacitor.With six diffusospheres,the multilayer heterogeneous capacitor achieves a recoverable energy storage density of 94 J/cm^(3),a significant advancement in BNTbased energy storage films.This work proposes and validates the concept of diffusospheres and their role in reducing interfacial polarization in multilayer heterogeneous films,enhancing the understanding of heterogeneous composite structures and advancing the field of dielectric energy storage.展开更多
In the research field of energy storage dielectrics,the“responsivity”parameter,defined as the recyclable/recoverable energy density per unit electric field,has become critically important for a comprehensive evaluat...In the research field of energy storage dielectrics,the“responsivity”parameter,defined as the recyclable/recoverable energy density per unit electric field,has become critically important for a comprehensive evaluation of the energy storage capability of a dielectric.In this work,high recyclable energy density and responsivity,i.e.,W_(rec)=161.1 J·cm^(-3) and ξ=373.8 J·(kV·m^(2))^(-1),have been simultaneously achieved in a prototype perovskite dielectric,BaTiO_(3),which is integrated on Si at 500℃ in the form of a submicron thick film.This ferroelectric film features a multi-scale polar structure consisting of ferroelectric grains with different orientations and inner-grain ferroelastic domains.A LaNiO_(3) buffer layer is used to induce a{001}textured,columnar nanograin microstructure,while an elevated deposition temperature promotes lateral growth of the nanograins(in-plane diameter increases from~10-20 nm at lower temperatures to~30 nm).These preferably oriented and periodically regulated nanograins have resulted in a small remnant polarization and a delayed polarization saturation in the film’s P-E behavior,leading to a high recyclable energy density.Meanwhile,an improved polarizability/dielectric constant of the BaTiO_(3) film has produced a much larger maximum polarization than those deposited at lower temperatures at the same electric field,leading to a record-breaking responsivity for this simple perovskite.展开更多
Dielectric capacitors with ultrahigh power density and ultra-fast charge/discharge rate are highly desired in pulse power fields.Environmental-friendly AgNbO_(3) family have been actively studied for its large polariz...Dielectric capacitors with ultrahigh power density and ultra-fast charge/discharge rate are highly desired in pulse power fields.Environmental-friendly AgNbO_(3) family have been actively studied for its large polarization and antiferroelectric nature,which greatly boost the electric energy storage performance.However,high-quality AgNbO_(3)-based films are difficult to fabricate,leading to a low breakdown field E_(b)(<1.2 MV/cm)and consequently arising inferior energy storage performance.In this work,we propose an interface engineering strategy to mitigate the breakdown field issue.A Ag(Nb,Ta)O_(3)/BaTiO_(3) bilayer film is proposed,where the BaTiO_(3) layer acts as a p-type semiconductor while Ag(Nb,Ta)O_(3) layer is n-type,together with the n-type LaNiO_(3) buffer layer on the substrate,forming an n-p-n heterostructure.The np-n heterostructure elevates the potential barriers for charge transport,greatly reducing the leakage current.An extremely large breakdown field E_(b)~4.3 MV/cm is achieved,being the highest value up to date in the niobate system.A high recoverable energy density Wrec~62.3 J/cm^(3) and a decent efficiency h~72.3%are obtained,much superior to that of the Ag(Nb,Ta)O_(3) monolayer film(W_(rec)~46.4 J/cm^(3) and h~80.3%at E_(b)~3.3 MV/cm).Our results indicate that interface engineering is an effective method to boost energy storage performance of dielectric film capacitors.展开更多
AgNbO_(3)-based antiferroelectric ceramics can be used to prepare dielectric ceramic materials with energy storage performance.However,their efficiency is much lower than that of relaxors,which is one of the biggest o...AgNbO_(3)-based antiferroelectric ceramics can be used to prepare dielectric ceramic materials with energy storage performance.However,their efficiency is much lower than that of relaxors,which is one of the biggest obstacles for their applications.To overcome this problem,AgNbO_(3) ceramics co-doped with Eu^(3+) and Ta^(5+) at the A-and B-sites were prepared in this work.The Ag_(0.97)Eu_(0.01)Nb_(0.85)Ta_(0.15)O_(3) sample has a Wr of 6.9 J/cm^(3) and an h of 74.6%.The ultrahigh energy storage density and efficiency of Ag_(0.97)Eu_(0.01)Nb_(0.85)Ta_(0.15)O_(3) has been ascribed to the synergistic effect of the increase in the breakdown electric field,the enhancement of antiferroelectric stability,the construction of multiphase coexistence,and the modification of the domain structure morphology.The Ag_(0.97)Eu_(0.01)Nb_(0.85)Ta_(0.15)O_(3) ceramic is expected to be one of the options for preparing dielectric capacitors.展开更多
Lead-free dielectric relaxor ferroelectric(RFE)ceramics are one of the promising materials for dielectric energy storage applications.However,the contradiction between high polarization and low hysteresis leads to int...Lead-free dielectric relaxor ferroelectric(RFE)ceramics are one of the promising materials for dielectric energy storage applications.However,the contradiction between high polarization and low hysteresis leads to interior energy storage performance,which greatly limits their applications in high/pulsed power systems.Here,we propose an effective strategy to significantly improve the energy storage properties of 0.94Bi_(0.5)Na_(0.5)TiO_(3)-0.06BaTiO_(3)(0.94BNT-0.06BT)with a morphotropic phase boundary(MPB)composition by constructing multiscale polymorphic domains and local heterogeneous structures.The introduction of Nd(Mg_(1/2)Hf_(1/2))O_(3)(NMH)facilitates the formation of short-range ordered polar nanoregions(PNRs).Moreover,small amounts of nanodomains with high polarization are resulted from local heterogeneous structures with Bi-and Ti-rich regions.Multiscale polymorphic domains with the coexistence of rhombohedral/tetragonal(R+T)nanodomains and PNRs ensure both high polarization and low hysteresis,which is crucial for improving the energy storage performance.Furthermore,the excellent electrical insulation is resulted from the high insulation resistivity,grain size at the submicron scale and a wide band gap by NMH doping.Therefore,a high recoverable energy density(Wrec)of 7.82 J/cm^(3) with an ultrahigh efficiency(η)of 93.1%is realized in the designed BNT-BT-NMH ternary system because of both a largeΔP and high Eb.These findings,together with good temperature/frequency/cycling stability,indicate that the optimum composition ceramics are very promising materials for energy storage applications in high/pulsed power systems.展开更多
Dielectric capacitors,serving as the indispensable components in advanced high-power energy storage devices,have attracted ever-increasing attention with the rapid development of science and technology.Among various d...Dielectric capacitors,serving as the indispensable components in advanced high-power energy storage devices,have attracted ever-increasing attention with the rapid development of science and technology.Among various dielectric capacitors,ceramic capacitors with perovskite structures show unique advantages in actual application,e.g.,excellent adaptability in high-temperature environments.And the optimization of their energy storage performance has become a hot research topic recently.This review presents the basic principles of energy storage in dielectric ceramics and introduces multi-scale synergic optimization strategies according to the key factors for superior energy storage performance.By summarizing the common points in numerous works,several universal modification strategies are reviewed,and future research on fatigue fracture of ceramic capacitors under multi-field including but not limited to force,electric,and thermal coupling conditions is also anticipated.展开更多
Relaxor dielectric ceramic capacitors are very attractive for high-power energy storage.However,the low breakdown strength severely restricts improvements to the energy storage density and practical application.Here,a...Relaxor dielectric ceramic capacitors are very attractive for high-power energy storage.However,the low breakdown strength severely restricts improvements to the energy storage density and practical application.Here,a strategy of designing small grain sizes and abundant amorphous grain boundaries is proposed to improve the energy storage properties under the guidance of phase field theory.0.925(K_(0.5)Na_(0.5))NbO_(3)-e0.075Bi(Zn_(2/3)(Ta_(0.5)Nb_(0.5))1/3)O_(3)(KNNe-BZTN)relaxor ferroelectric ceramic is taken as an example to verify our strategy.The grain sizes and grain boundaries of the KNNeBZTN ceramics are carefully controlled by the high-energy ball milling method and twoestep sintering strategy.Impedance analysis and diffusion reflectance spectra demonstrate that KNNeBZTN ceramics with a small grain size and abundant amorphous grain boundary exhibit a lower charge carrier concentration and higher band gap.As a consequence,the breakdown electric field of KNNeBZTN ceramics increases from 222 kV/cm to 317 kV/cm when the grain size is decreased from 410 nm to 200 nm,accompanied by a slightly degraded maximum polarization.KNNeBZTN ceramics with an average grain size of~250 nm and abundant amorphous grain boundaries exhibit optimum energy storage properties with a high recoverable energy density of 4.02 J/cm^(3) and a high energy efficiency of 87.4%.This successful local structural design opens up a new paradigm to improve the energy storage performance of other dielectric ceramic capacitors for electrical energy storage.展开更多
Advances in flexible electronics are driving dielectric capacitors with high energy storage density toward flexibility and miniaturization.In the present work,an all-inorganic thin film dielectric capacitor with the c...Advances in flexible electronics are driving dielectric capacitors with high energy storage density toward flexibility and miniaturization.In the present work,an all-inorganic thin film dielectric capacitor with the coexistence of ferroelectric(FE)and antiferroelectric(AFE)phases based on Pb_(0.96)La_(0.04)(Zr_(0.95)Ti_(0.05))O_(3)(PLZT)was prepared on a 2D fluorophlogopite mica substrate via a simple one-step process.The flexible capacitor exhibits a high recoverable energy density(U_(rec))of z 44.2 J/cm^(3),a large electric breakdown strength(E BDS)of 3011 kV/cm,excellent frequency stability(500 Hz-20 kHz)and high thermal stability over 30-190℃.It also demonstrates an outstanding bending endurance,which can maintain a high energy storage performance under various bending radii(R=2-10 mm)or 103 repeated bends at 4 mm.The FE phase is stable near the film surface and the interface with the bottom electrode.The AFE phase with multi-domains has incommensurate modulation structures with super-periodicity of 6.5,6.9 and 5.2.It indicates that the PLZT/LNO/F-Mica capacitor has high potential for energy storage application and may provide great opportunities for exploring new energy storage materials.展开更多
Polymer-based dielectric capacitors are widely-used energy storage devices.However,although the functions of dielectrics in applications like high-voltage direct current transmission projects,distributed energy system...Polymer-based dielectric capacitors are widely-used energy storage devices.However,although the functions of dielectrics in applications like high-voltage direct current transmission projects,distributed energy systems,high-power pulse systems and new energy electric vehicles are similar,their requirements can be quite different.Low electric loss is a critical prerequisite for capacitors for electric grids,while high-temperature stability is an essential pre-requirement for those in electric vehicles.This paper reviews recent advances in this area,and categorizes dielectrics in terms of their foremost properties related to their target applications.Requirements for polymer-based dielectrics in various power electronic equipment are emphasized,including high energy storage density,low dissipation,high working temperature and fast-response time.This paper considers innovations including chemical structure modification,composite fabrication and structure re-design,and the enhancements to material performances achieved.The advantages and limitations of these methods are also discussed.展开更多
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
Dielectric capacitors have been widely used in pulsed power devices owing to their ultrahigh power density,fast charge/discharge speed,and excellent stability.However,developing lead-free dielectric materials with a c...Dielectric capacitors have been widely used in pulsed power devices owing to their ultrahigh power density,fast charge/discharge speed,and excellent stability.However,developing lead-free dielectric materials with a combination of high recoverable energy storage density and efficiency remains a challenge.Herein,a high energy storage density of 7.04 J/cm^(3) as well as a high efficiency of 80.5%is realized in the antiferroelectric Ag(Nb_(0.85)Ta_(0.15))O_(3)-modified BiFeO3-BaTiO3 ferroelectric ceramic.This achievement is mainly attributed to the combined effect of a high saturation polarization(Pmax),increased breakdown field(Eb),and reduction of the remnant polarization(Pr).The modification of pseudotetragonal BiFeO3 by Ag(Nb_(0.85)Ta_(0.15))O_(3) leads to a high Pmax,and the enhanced relaxor behavior gives rise to a small Pr.The promoted microstructure(such as a dense structure,fine grains,and compact grain boundaries)after modification results in a high breakdown strength.Furthermore,both the recoverable energy density and efficiency exhibit high stability over a broad range of operating frequencies(1–50 Hz)and working temperatures(25–120℃).These results suggest that the(0.67–x)BiFeO_(3)-0.33BaTiO_(3)-xAg(Nb_(0.85)Ta_(0.15))O_(3) ceramics can be highly competitive as a lead-free relaxor for energy storage applications.展开更多
The NaNbO_(3) antiferroelectrics have been considered as a potential candidate for dielectric capacitorsapplications. However, the high-electric-field-unstable antiferroelectric phase resulted in low energystorage den...The NaNbO_(3) antiferroelectrics have been considered as a potential candidate for dielectric capacitorsapplications. However, the high-electric-field-unstable antiferroelectric phase resulted in low energystorage density and efficiency. Herein, good energy storage properties were realized in (1-x)NaNbO_(3)- xNaTaO_(3) ceramics, by building a new phase boundary. As a result, a high recoverable energy density(Wrec) of 2.2 J/cm3 and efficiency (h) of 80.1% were achieved in 0.50NaNbO_(3)-0.50NaTaO_(3) ceramic at300 kV/cm. The excellent energy storage performance originates from an antiferroelectric-paraelectricphase boundary with simultaneously high polarization and low hysteresis, by tailoring the ratio ofantiferroelectric and paraelectric phases. Moreover, the 0.50NaNbO_(3)-0.50NaTaO_(3) ceramic also exhibitedgood temperature and frequency stability, together with excellent charge-discharge performance. Theresults pave a good way of designing new NaNbO_(3)-based antiferroelectrics with good energy storageperformance.展开更多
With its extremely strong capability of data analysis,machine learning has shown versatile potential in the revolution of the materials research paradigm.Here,taking dielectric capacitors and lithium‐ion batteries as...With its extremely strong capability of data analysis,machine learning has shown versatile potential in the revolution of the materials research paradigm.Here,taking dielectric capacitors and lithium‐ion batteries as two representa-tive examples,we review substantial advances of machine learning in the research and development of energy storage materials.First,a thorough discussion of the machine learning framework in materials science is presented.Then,we summarize the applications of machine learning from three aspects,including discovering and designing novel materials,enriching theoretical simulations,and assisting experimentation and characterization.Finally,a brief outlook is highlighted to spark more insights on the innovative implementation of machine learning in materials science.展开更多
Although dielectric ceramic capacitors possess attractive properties for high-power energy storage,their pronounced electrostriction effect and high brittleness are conducive to easy initiation and propagation of crac...Although dielectric ceramic capacitors possess attractive properties for high-power energy storage,their pronounced electrostriction effect and high brittleness are conducive to easy initiation and propagation of cracks that significantly deteriorate electrical reliability and lifetime of capacitors in practical applications.Herein,a new strategy for designing relaxor ferroelectric ceramics with K_(0.5)Na_(0.5)NbO_(3)-core/SiO_(2)-shell structured grains was proposed to simultaneously reduce the electric-field-induced strain and enhance the mechanical strength of the ceramics.The simulation and experiment declared that the bending strength and compression strength of the core-shell structured ceramic were shown to increase by more than 50% over those of the uncoated sample.Meanwhile,the electric-field-induced strain was reduced by almost half after adding the SiO_(2) coating.The suppressed electrical deformation and enhanced mechanical strength could alleviate the probability of generation of cracks and prevent their propagation,thus remarkably improving breakdown strength and fatigue endurance of the ceramics.As a result,an ultra-high breakdown strength of 425 kV cm^(-1) and excellent recoverable energy storage density(Wrec~4.64 J cm^(-3))were achieved in the core-shell structured sample.More importantly,the unique structure could enhance the cycling stability of the ceramic(Wrec variation<±2% after 105 cycles).Thus,mechanical performance optimization via grain structure engineering offers a new paradigm for improving electrical breakdown strength and fatigue endurance of dielectric ceramic capacitors.展开更多
Dielectric materials with high energy storage density(Wrec)and efficiency(η)are expected for energy storage capacitors.In this work,<001>-textured Na0.7Bi0.1NbO_(3)(NBN)ceramics were prepared by a templated gra...Dielectric materials with high energy storage density(Wrec)and efficiency(η)are expected for energy storage capacitors.In this work,<001>-textured Na0.7Bi0.1NbO_(3)(NBN)ceramics were prepared by a templated grain growth technique.The effects of microstructure and orientation degree on dielectric properties,polarization and energy storage performance were investigated.The textured ceramic with an optimized orientation degree(70%)showed a high Wrec of 2.4 J/cm^(3) andηof 85.6%.The excellent energy storage properties of textured ceramic originate from the co-effect of interfacial polarization and clamping effect.The results indicate that texture development is a potential candidate to optimize the energy storage properties of functional ceramics.展开更多
基金the funding of National Key R&D Program of China(No.2020YFA0711700)Hunan National Natural Science Foundation(2021JJ30652)+3 种基金National Natural Science Foundation of China(52002404)Natural Science Foundation of Guangdong Province(2020A1515011198)Characteristic Innovation Projects of Colleges and Universities in Guangdong Province(2020KT SCX081)State Key Laboratory of Powder Metallurgy,Central South University,Changsha,China
文摘How to achieve synergistic improvement of permittivity(ε_(r))and breakdown strength(E_(b))is a huge challenge for polymer dielectrics.Here,for the first time,theπ-conjugated comonomer(MHT)can simultaneously promote theε_(r)and E_(b)of linear poly(methyl methacrylate)(PMMA)copolymers.The PMMA-based random copolymer films(P(MMA-co-MHT)),block copolymer films(PMMA-b-PMHT),and PMMA-based blend films were prepared to investigate the effects of sequential structure,phase separation structure,and modification method on dielectric and energy storage properties of PMMA-based dielectric films.As a result,the random copolymer P(MMA-coMHT)can achieve a maximumε_(r)of 5.8 at 1 kHz owing to the enhanced orientation polarization and electron polarization.Because electron injection and charge transfer are limited by the strong electrostatic attraction ofπ-conjugated benzophenanthrene group analyzed by the density functional theory(DFT),the discharge energy density value of P(MMA-co-PMHT)containing 1 mol%MHT units with the efficiency of 80%reaches15.00 J cm^(-3)at 872 MV m^(-1),which is 165%higher than that of pure PMMA.This study provides a simple and effective way to fabricate the high performance of polymer dielectrics via copolymerization with the monomer of P-type semi-conductive polymer.
基金supported by the Slovenian Research Agency(Nos.P2-0091,J2-2510,N2-0187,N2-0149,and P1-0125)the Swiss National Science Foundation(Lead Agency Grant No.192047)the Region Hauts-de-France(Projects TERRA(AAP STARS-N°21002758)and TRANSITION(CPER MANIFEST-N°22006563)).
文摘Ensuring reliable and safe operation of high-power electronic devices necessitates the development of high-quality dielectric nano-capacitors with high recoverable energy density(URec)and efficiency(η)at low applied electric fields(E)/voltages.In this work,we demonstrate ultra-high URec andηat low E<500 kV/cm in as-grown epitaxial relaxor ferroelectric(RFE)PMN-33PT films,rivaling those typically achieved in state-of-the-art RFE and antiferroelectric(AFE)materials.The high energy storage properties were achieved using a synergistic strategy involving large polarization,a giant built-in potential/imprint(five times higher than the coercive field),and AFE like behavior.The structural,chemical,and electrical investigations revealed that these achievements mainly arise from the effects of strain,dipole defects,and chemical composition.For instance,at low E,the capacitors exhibit under 160 kV/cm(i.e.,8 V)and 400 kV/cm(i.e.,20 V),respectively,an ultra-highΔP(45μC/cm^(2)and 60μC/cm^(2)),UE=URec/E(21 J·MV/cm^(2)and 17 J·MV/cm^(2)),and UF=URec/(1-η)(20 J/cm^(3)and 47 J/cm^(3))with a robust charge-discharge fatigue endurance and outstanding frequency and thermal stability.Additionally,the designed films exhibit outstanding energy storage performance at higher E up to 2 MV/cm(ΔP≈78μC/cm^(2),UE≈17.3 J·MV/cm^(2)and UF≈288 J/cm^(3))due to their low leakage current density.
基金supported by the Key Project of the Anhui Provincial Department of Education Fund(No.2023AH051103)the National Innovation and Entrepreneurship Training Program for College Students(Nos.202410360029 and 202310360023)+1 种基金the Anhui Provincial Natural Science Foundation(No.2108085QE193)the Guangdong Provincial Key Laboratory of Electronic Functional Materials and Devices(No.EFMD2024013M).
文摘Antiferroelectric(AFE)ceramic materials with excellent temperature stability are critical for meeting ever-increasing demands for practical energy storage applications.However,how to remain high dielectric breakdown strategy at high temperature,at the same time to keep energy storage density(W_(rec))with high energy storage efficiency(η)is still a major challenge.In this work,polyurethane-Cu(PU-Cu)was introduced into a(Pb_(0.64)Tm_(0.04)La_(0.2))(Zr_(0.55)Sn_(0.44)Ti_(0.01))(PTL2ZST)AFE thick film to enhance the energy storage performance at high temperatures.PTL2ZST dispersed in PU-Cu because PU-Cu functions by introducing carrier traps,reducing conduction and leakage currents at high temperatures.As a result,at a working temperature of 140℃,its W_(rec)andηremain within the range of±5%compared with those of pure PTL2ZST(W_(rec)decreases by 21.7%,ηincreases by 9.4%at 100℃).Furthermore,ultrahigh W_(rec)of 17.01 J/cm^(3)withηof 80.31%in PTL2ZST-90%PU-Cu thick films at 2500 kV/cm at room temperature(RT)was obtained.Moreover,this study has outstanding filtering performance because the high degree of insulation caused by carrier traps weakens the charge carrier transport.In the rectifier circuit,the PTL2ZST-90%PU-Cu films can filter off 90%of the clutter.This study provides a feasible method to produce high-performance dielectric materials because of their high energy storage performance and heat resistance,which also broadens the field of filter application.
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supported by the National Natural Science Foundation of China(Grant Nos.52032007,52302145)the Natural Science Foundation of Shandong Province(ZR2023QE126).
文摘Combining layers with high breakdown resistance and high polarization is a promising approach for designing dielectric capacitors with high energy density and efficiency.However,such combinations often accompany strong interfacial polarization,magnification of local electric fields,leading to premature breakdown.This work addresses this issue via controlled formation of diffusospheres.We constructed multilayer heterogeneous films using two Bi_(0.5)Na_(0.5)TiO_(3)(BNT)-based substances with high breakdown resistance and high polarization properties.Experimental results and finite element simulations demonstrate that the energy storage capacity of these films effectively harnesses the advantages of both phases.Notably,the interface polarization is minimal.Instead,a solid solution-like diffusosphere,formed by the mutual diffusion of ions between the two phases,plays a crucial role.The diffusosphere acts as a transition zone,mitigating charge aggregation at the interfaces and optimizing the relaxor and breakdown characteristics of the capacitor.With six diffusospheres,the multilayer heterogeneous capacitor achieves a recoverable energy storage density of 94 J/cm^(3),a significant advancement in BNTbased energy storage films.This work proposes and validates the concept of diffusospheres and their role in reducing interfacial polarization in multilayer heterogeneous films,enhancing the understanding of heterogeneous composite structures and advancing the field of dielectric energy storage.
基金the National Natural Science Foundation of China(Grant Nos.51772175 and 52002192)Natural Science Foundation of Shandong Province(Grant Nos.ZR2022ZD39,ZR2022ME075,ZR2020QE042,ZR2022ME031,and ZR2022QB138)+3 种基金the Science,Education and Industry Integration Pilot Projects of Qilu University of Technology(Shandong Academy of Sciences)(Grant Nos.2022GH018 and 2022PY055)the Jinan City Science and Technology Bureau(Grant No.2021GXRC055)the Education Department of Hunan Province/Xiangtan University(Grant No.KZ0807969)funding for top talents at Qilu University of Technology(Shandong Academy of Sciences).
文摘In the research field of energy storage dielectrics,the“responsivity”parameter,defined as the recyclable/recoverable energy density per unit electric field,has become critically important for a comprehensive evaluation of the energy storage capability of a dielectric.In this work,high recyclable energy density and responsivity,i.e.,W_(rec)=161.1 J·cm^(-3) and ξ=373.8 J·(kV·m^(2))^(-1),have been simultaneously achieved in a prototype perovskite dielectric,BaTiO_(3),which is integrated on Si at 500℃ in the form of a submicron thick film.This ferroelectric film features a multi-scale polar structure consisting of ferroelectric grains with different orientations and inner-grain ferroelastic domains.A LaNiO_(3) buffer layer is used to induce a{001}textured,columnar nanograin microstructure,while an elevated deposition temperature promotes lateral growth of the nanograins(in-plane diameter increases from~10-20 nm at lower temperatures to~30 nm).These preferably oriented and periodically regulated nanograins have resulted in a small remnant polarization and a delayed polarization saturation in the film’s P-E behavior,leading to a high recyclable energy density.Meanwhile,an improved polarizability/dielectric constant of the BaTiO_(3) film has produced a much larger maximum polarization than those deposited at lower temperatures at the same electric field,leading to a record-breaking responsivity for this simple perovskite.
基金the financial support from the National Natural Science Foundation of China(Grant No.52072218,12334006,51772175 and 52002192)National Key R&D Program of China(Grant No.2021YFB3601504)+4 种基金Natural Science Foundation of Shandong Province(Grant No.ZR2020QE042,ZR2020KE019,ZR2022ZD39,ZR2022ME075,ZR2022QB138,ZR2022ME031 and ZR2022YQ43)the Science,Education and Industry Integration Pilot Projects of Qilu University of Technology(Shandong Academy of Sciences)(Grant Nos.2022GH018,2022PY055)J.Ouyang acknowledges the support from the Jinan City Science and Technology Bureau(Grant No.2021GXRC055)the Education Department of Hunan Province/Xiangtan University(Grant No.KZ0807969)the seed funding for top talents at Qilu University of Technology(Shandong Academy of Sciences).We would like to thank the Analytical Center for Structural Constituent and Physical Property of Core Facilities Sharing Platform,Shandong University for XRD,SEM and XPS analysis.
文摘Dielectric capacitors with ultrahigh power density and ultra-fast charge/discharge rate are highly desired in pulse power fields.Environmental-friendly AgNbO_(3) family have been actively studied for its large polarization and antiferroelectric nature,which greatly boost the electric energy storage performance.However,high-quality AgNbO_(3)-based films are difficult to fabricate,leading to a low breakdown field E_(b)(<1.2 MV/cm)and consequently arising inferior energy storage performance.In this work,we propose an interface engineering strategy to mitigate the breakdown field issue.A Ag(Nb,Ta)O_(3)/BaTiO_(3) bilayer film is proposed,where the BaTiO_(3) layer acts as a p-type semiconductor while Ag(Nb,Ta)O_(3) layer is n-type,together with the n-type LaNiO_(3) buffer layer on the substrate,forming an n-p-n heterostructure.The np-n heterostructure elevates the potential barriers for charge transport,greatly reducing the leakage current.An extremely large breakdown field E_(b)~4.3 MV/cm is achieved,being the highest value up to date in the niobate system.A high recoverable energy density Wrec~62.3 J/cm^(3) and a decent efficiency h~72.3%are obtained,much superior to that of the Ag(Nb,Ta)O_(3) monolayer film(W_(rec)~46.4 J/cm^(3) and h~80.3%at E_(b)~3.3 MV/cm).Our results indicate that interface engineering is an effective method to boost energy storage performance of dielectric film capacitors.
基金supported by the National Science Foundation of China(NSFC No.52172119)Shaanxi Province Postdoctoral Science Foundation(2023BSHYDZZ105)the Fundamental Research Funds for the Central Universities(GK202304007).
文摘AgNbO_(3)-based antiferroelectric ceramics can be used to prepare dielectric ceramic materials with energy storage performance.However,their efficiency is much lower than that of relaxors,which is one of the biggest obstacles for their applications.To overcome this problem,AgNbO_(3) ceramics co-doped with Eu^(3+) and Ta^(5+) at the A-and B-sites were prepared in this work.The Ag_(0.97)Eu_(0.01)Nb_(0.85)Ta_(0.15)O_(3) sample has a Wr of 6.9 J/cm^(3) and an h of 74.6%.The ultrahigh energy storage density and efficiency of Ag_(0.97)Eu_(0.01)Nb_(0.85)Ta_(0.15)O_(3) has been ascribed to the synergistic effect of the increase in the breakdown electric field,the enhancement of antiferroelectric stability,the construction of multiphase coexistence,and the modification of the domain structure morphology.The Ag_(0.97)Eu_(0.01)Nb_(0.85)Ta_(0.15)O_(3) ceramic is expected to be one of the options for preparing dielectric capacitors.
基金supported by the National Key R&D Program of China(No.2021YFB3201100)the National Natural Science Foundation of China(Nos.51931004,12264012,52172128 and 52472250)+2 种基金111 Project 2.0(No.BP2018008)the Natural Science Foundation of Guangxi(Nos.AB24010230,AA22068080,and AA23023027)the Science and Technology Plan of Guilin(Nos.2022H03 and ZY20220101).
文摘Lead-free dielectric relaxor ferroelectric(RFE)ceramics are one of the promising materials for dielectric energy storage applications.However,the contradiction between high polarization and low hysteresis leads to interior energy storage performance,which greatly limits their applications in high/pulsed power systems.Here,we propose an effective strategy to significantly improve the energy storage properties of 0.94Bi_(0.5)Na_(0.5)TiO_(3)-0.06BaTiO_(3)(0.94BNT-0.06BT)with a morphotropic phase boundary(MPB)composition by constructing multiscale polymorphic domains and local heterogeneous structures.The introduction of Nd(Mg_(1/2)Hf_(1/2))O_(3)(NMH)facilitates the formation of short-range ordered polar nanoregions(PNRs).Moreover,small amounts of nanodomains with high polarization are resulted from local heterogeneous structures with Bi-and Ti-rich regions.Multiscale polymorphic domains with the coexistence of rhombohedral/tetragonal(R+T)nanodomains and PNRs ensure both high polarization and low hysteresis,which is crucial for improving the energy storage performance.Furthermore,the excellent electrical insulation is resulted from the high insulation resistivity,grain size at the submicron scale and a wide band gap by NMH doping.Therefore,a high recoverable energy density(Wrec)of 7.82 J/cm^(3) with an ultrahigh efficiency(η)of 93.1%is realized in the designed BNT-BT-NMH ternary system because of both a largeΔP and high Eb.These findings,together with good temperature/frequency/cycling stability,indicate that the optimum composition ceramics are very promising materials for energy storage applications in high/pulsed power systems.
基金supported by the National Natural Science Foundation of China(52073144 and 12004181)the Natural Science Foundation of Jiangsu Province(BK20201301 and BK20200473)+2 种基金State Key Laboratory of New Ceramics and Fine Processing,Tsinghua University(KF202114)the Research Fund of State Key Laboratory of Mechanics and Control of Mechanical Structures,Nanjing University of Aeronautics and Astronautics(MCMS-I-0522G02)a Project Funded by a project of the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions.
文摘Dielectric capacitors,serving as the indispensable components in advanced high-power energy storage devices,have attracted ever-increasing attention with the rapid development of science and technology.Among various dielectric capacitors,ceramic capacitors with perovskite structures show unique advantages in actual application,e.g.,excellent adaptability in high-temperature environments.And the optimization of their energy storage performance has become a hot research topic recently.This review presents the basic principles of energy storage in dielectric ceramics and introduces multi-scale synergic optimization strategies according to the key factors for superior energy storage performance.By summarizing the common points in numerous works,several universal modification strategies are reviewed,and future research on fatigue fracture of ceramic capacitors under multi-field including but not limited to force,electric,and thermal coupling conditions is also anticipated.
基金supported by the National Natural Science Foundation of China(Grant Nos.52072150,51702119,51702122,51972146)Young Elite Scientists Sponsorship Program by CAST.
文摘Relaxor dielectric ceramic capacitors are very attractive for high-power energy storage.However,the low breakdown strength severely restricts improvements to the energy storage density and practical application.Here,a strategy of designing small grain sizes and abundant amorphous grain boundaries is proposed to improve the energy storage properties under the guidance of phase field theory.0.925(K_(0.5)Na_(0.5))NbO_(3)-e0.075Bi(Zn_(2/3)(Ta_(0.5)Nb_(0.5))1/3)O_(3)(KNNe-BZTN)relaxor ferroelectric ceramic is taken as an example to verify our strategy.The grain sizes and grain boundaries of the KNNeBZTN ceramics are carefully controlled by the high-energy ball milling method and twoestep sintering strategy.Impedance analysis and diffusion reflectance spectra demonstrate that KNNeBZTN ceramics with a small grain size and abundant amorphous grain boundary exhibit a lower charge carrier concentration and higher band gap.As a consequence,the breakdown electric field of KNNeBZTN ceramics increases from 222 kV/cm to 317 kV/cm when the grain size is decreased from 410 nm to 200 nm,accompanied by a slightly degraded maximum polarization.KNNeBZTN ceramics with an average grain size of~250 nm and abundant amorphous grain boundaries exhibit optimum energy storage properties with a high recoverable energy density of 4.02 J/cm^(3) and a high energy efficiency of 87.4%.This successful local structural design opens up a new paradigm to improve the energy storage performance of other dielectric ceramic capacitors for electrical energy storage.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51971030 and 11775018)Beijing Municipal Natural Science Foundation 2202032.
文摘Advances in flexible electronics are driving dielectric capacitors with high energy storage density toward flexibility and miniaturization.In the present work,an all-inorganic thin film dielectric capacitor with the coexistence of ferroelectric(FE)and antiferroelectric(AFE)phases based on Pb_(0.96)La_(0.04)(Zr_(0.95)Ti_(0.05))O_(3)(PLZT)was prepared on a 2D fluorophlogopite mica substrate via a simple one-step process.The flexible capacitor exhibits a high recoverable energy density(U_(rec))of z 44.2 J/cm^(3),a large electric breakdown strength(E BDS)of 3011 kV/cm,excellent frequency stability(500 Hz-20 kHz)and high thermal stability over 30-190℃.It also demonstrates an outstanding bending endurance,which can maintain a high energy storage performance under various bending radii(R=2-10 mm)or 103 repeated bends at 4 mm.The FE phase is stable near the film surface and the interface with the bottom electrode.The AFE phase with multi-domains has incommensurate modulation structures with super-periodicity of 6.5,6.9 and 5.2.It indicates that the PLZT/LNO/F-Mica capacitor has high potential for energy storage application and may provide great opportunities for exploring new energy storage materials.
基金This research was supported by Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ18E030004)State Key Laboratory of Electrical Insulation and Power Equipment(Grant No.EIPE19204)Zhejiang Top Priority Discipline of Textile Science and Engineering/Material Science and Engineering(Grant No.2019YBZX03).
文摘Polymer-based dielectric capacitors are widely-used energy storage devices.However,although the functions of dielectrics in applications like high-voltage direct current transmission projects,distributed energy systems,high-power pulse systems and new energy electric vehicles are similar,their requirements can be quite different.Low electric loss is a critical prerequisite for capacitors for electric grids,while high-temperature stability is an essential pre-requirement for those in electric vehicles.This paper reviews recent advances in this area,and categorizes dielectrics in terms of their foremost properties related to their target applications.Requirements for polymer-based dielectrics in various power electronic equipment are emphasized,including high energy storage density,low dissipation,high working temperature and fast-response time.This paper considers innovations including chemical structure modification,composite fabrication and structure re-design,and the enhancements to material performances achieved.The advantages and limitations of these methods are also discussed.
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 Basic Science Center Project of NSFC no.52388201Tsinghua University-Toyota Research Center.
文摘Dielectric capacitors have been widely used in pulsed power devices owing to their ultrahigh power density,fast charge/discharge speed,and excellent stability.However,developing lead-free dielectric materials with a combination of high recoverable energy storage density and efficiency remains a challenge.Herein,a high energy storage density of 7.04 J/cm^(3) as well as a high efficiency of 80.5%is realized in the antiferroelectric Ag(Nb_(0.85)Ta_(0.15))O_(3)-modified BiFeO3-BaTiO3 ferroelectric ceramic.This achievement is mainly attributed to the combined effect of a high saturation polarization(Pmax),increased breakdown field(Eb),and reduction of the remnant polarization(Pr).The modification of pseudotetragonal BiFeO3 by Ag(Nb_(0.85)Ta_(0.15))O_(3) leads to a high Pmax,and the enhanced relaxor behavior gives rise to a small Pr.The promoted microstructure(such as a dense structure,fine grains,and compact grain boundaries)after modification results in a high breakdown strength.Furthermore,both the recoverable energy density and efficiency exhibit high stability over a broad range of operating frequencies(1–50 Hz)and working temperatures(25–120℃).These results suggest that the(0.67–x)BiFeO_(3)-0.33BaTiO_(3)-xAg(Nb_(0.85)Ta_(0.15))O_(3) ceramics can be highly competitive as a lead-free relaxor for energy storage applications.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.11864004 and 52072080)The author also thanks to the fund(Grant No.20KF-16)from the Key Laboratory of New Processing Technology for Nonferrous Metal&Materials,Ministry of Education/Guangxi Key Laboratory of Optical and Electronic Materials and Devices,Guilin University of Technology,Guilin(541004),China.
文摘The NaNbO_(3) antiferroelectrics have been considered as a potential candidate for dielectric capacitorsapplications. However, the high-electric-field-unstable antiferroelectric phase resulted in low energystorage density and efficiency. Herein, good energy storage properties were realized in (1-x)NaNbO_(3)- xNaTaO_(3) ceramics, by building a new phase boundary. As a result, a high recoverable energy density(Wrec) of 2.2 J/cm3 and efficiency (h) of 80.1% were achieved in 0.50NaNbO_(3)-0.50NaTaO_(3) ceramic at300 kV/cm. The excellent energy storage performance originates from an antiferroelectric-paraelectricphase boundary with simultaneously high polarization and low hysteresis, by tailoring the ratio ofantiferroelectric and paraelectric phases. Moreover, the 0.50NaNbO_(3)-0.50NaTaO_(3) ceramic also exhibitedgood temperature and frequency stability, together with excellent charge-discharge performance. Theresults pave a good way of designing new NaNbO_(3)-based antiferroelectrics with good energy storageperformance.
基金This study was supported by the Basic Science Center Program of NSFC(Grant No.51788104)Major Research Plan of NSFC(Grant No.92066103)+2 种基金NSF of China(Grant No.52002300)Major Program of NSFC(Grant No.51790490)Young Elite Scientists Sponsorship Program by CAST(Frant No.2019QNRC001)。
文摘With its extremely strong capability of data analysis,machine learning has shown versatile potential in the revolution of the materials research paradigm.Here,taking dielectric capacitors and lithium‐ion batteries as two representa-tive examples,we review substantial advances of machine learning in the research and development of energy storage materials.First,a thorough discussion of the machine learning framework in materials science is presented.Then,we summarize the applications of machine learning from three aspects,including discovering and designing novel materials,enriching theoretical simulations,and assisting experimentation and characterization.Finally,a brief outlook is highlighted to spark more insights on the innovative implementation of machine learning in materials science.
基金This work was supported by the National Natural Science Foundation of China(grants nos.52072150,51972146,and 51772175)the China Association for Science and Technology(Young Elite Scientists Sponsorship Program)the State Key Laboratory of New Ceramic and Fine Processing Tsinghua University(project no.KF202002).
文摘Although dielectric ceramic capacitors possess attractive properties for high-power energy storage,their pronounced electrostriction effect and high brittleness are conducive to easy initiation and propagation of cracks that significantly deteriorate electrical reliability and lifetime of capacitors in practical applications.Herein,a new strategy for designing relaxor ferroelectric ceramics with K_(0.5)Na_(0.5)NbO_(3)-core/SiO_(2)-shell structured grains was proposed to simultaneously reduce the electric-field-induced strain and enhance the mechanical strength of the ceramics.The simulation and experiment declared that the bending strength and compression strength of the core-shell structured ceramic were shown to increase by more than 50% over those of the uncoated sample.Meanwhile,the electric-field-induced strain was reduced by almost half after adding the SiO_(2) coating.The suppressed electrical deformation and enhanced mechanical strength could alleviate the probability of generation of cracks and prevent their propagation,thus remarkably improving breakdown strength and fatigue endurance of the ceramics.As a result,an ultra-high breakdown strength of 425 kV cm^(-1) and excellent recoverable energy storage density(Wrec~4.64 J cm^(-3))were achieved in the core-shell structured sample.More importantly,the unique structure could enhance the cycling stability of the ceramic(Wrec variation<±2% after 105 cycles).Thus,mechanical performance optimization via grain structure engineering offers a new paradigm for improving electrical breakdown strength and fatigue endurance of dielectric ceramic capacitors.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52072080 and 11864004)the Guangxi Natural Science Fund for Distinguished Young Scholars(Grant No.2022GXNSFFA035034).
文摘Dielectric materials with high energy storage density(Wrec)and efficiency(η)are expected for energy storage capacitors.In this work,<001>-textured Na0.7Bi0.1NbO_(3)(NBN)ceramics were prepared by a templated grain growth technique.The effects of microstructure and orientation degree on dielectric properties,polarization and energy storage performance were investigated.The textured ceramic with an optimized orientation degree(70%)showed a high Wrec of 2.4 J/cm^(3) andηof 85.6%.The excellent energy storage properties of textured ceramic originate from the co-effect of interfacial polarization and clamping effect.The results indicate that texture development is a potential candidate to optimize the energy storage properties of functional ceramics.
