Advanced lead-free energy storage ceramics play an indispensable role in next-generation pulse power capacitors market.Here,an ultrahigh energy storage density of~13.8 J cm^(-3)and a large efficiency of~82.4%are achie...Advanced lead-free energy storage ceramics play an indispensable role in next-generation pulse power capacitors market.Here,an ultrahigh energy storage density of~13.8 J cm^(-3)and a large efficiency of~82.4%are achieved in high-entropy lead-free relaxor ferroelectrics by increasing configuration entropy,named high-entropy strategy,realizing nearly ten times growth of energy storage density compared with low-entropy material.Evolution of energy storage performance and domain structure with increasing configuration entropy is systematically revealed for the first time.The achievement of excellent energy storage properties should be attributed to the enhanced random field,decreased nanodomain size,strong multiple local distortions,and improved breakdown field.Furthermore,the excellent frequency and fatigue stability as well as charge/discharge properties with superior thermal stability are also realized.The significantly enhanced comprehensive energy storage performance by increasing configuration entropy demonstrates that high entropy is an effective but convenient strategy to design new high-performance dielectrics,promoting the development of advanced capacitors.展开更多
High-performance ferroelectric materials are widely used in various electronic devices owing to the function of mutual conversion among different energies,which mainly relates to their special structure gene of polari...High-performance ferroelectric materials are widely used in various electronic devices owing to the function of mutual conversion among different energies,which mainly relates to their special structure gene of polarization configuration.Recent researches show that the high-entropy strategy has emerged as an effective and flexible approach for boosting physical properties in high-entropy ferroelectrics via the delicate design of local polarization configurations and other intrinsic effects caused by entropy increment,such as entropy stabilization,lattice disorder,inhibition of grain coarsening,improved mechanical properties,cocktail effect,and so on.In this review,the recent research progress about high-entropy ferroelectrics has been summarized,especially for the directional design of novel local polarization configurations according to the characteristics of different electrical properties such as high piezoelectricity,high-efficiency energy storage,and large electrostriction,providing a guidance for designing and exploring more novel local polarization configurations in high-entropy ferroelectrics for generating higher performance.展开更多
Electrostrictive materials have wide applications in modern high-precision electronic devices.Driven by growing environmental concerns,there is demand for lead-free materials with superior electrostriction behaviors.I...Electrostrictive materials have wide applications in modern high-precision electronic devices.Driven by growing environmental concerns,there is demand for lead-free materials with superior electrostriction behaviors.In this study,we demonstrate a record-high electrostrictive coefficient of~0.0712 m^(4) C^(-2) in perovskite ferroelectric ceramics,along with hysteresis-free strain as well as excellent frequency and thermal stabilities,in lead-free BaTiO_(3)-based ceramics through a polarization nanocluster design.By appro-priately introducing Li+and Bi^(3+)into the BaTiO 3 lattice matrix,the long-range ferroelectric ordering can be broken,and polarization nanoclusters can be formed,resulting in a relaxor state with concurrently suppressed polariza-tion and maintained electro-strain.A three-dimensional atomic model constructed using advanced neutron total-scattering data combined with the reverse Monte Carlo method indicates the existence of Bi and Li segregations at the subnanometer scale,which confirms the prediction made by density functional theory calculations.Such a short-range chemical order destroys the long-range ferroelectric order of the off-centered Ti polar displacements and leads to the embedding of Li+/Bi ^(3+)-rich polar nanoregions in the Ba^(2+)-rich polarization disorder matrix.Further,a completely reversible electric-field-induced lattice strain is observed,giving rise to pure electrostriction without hysteresis behavior.This work provides a novel strategy for developing lead-free relaxor ferroelectrics with high electrostriction performance.展开更多
Bi_(0.5)Na_(0.5)TiO_(3)-BaTiO_(3)(BNT-100xBT)ceramics are promising candidates for piezoelectric applications.The correlation between their structure and piezoelectric properties has attracted considerable interest.He...Bi_(0.5)Na_(0.5)TiO_(3)-BaTiO_(3)(BNT-100xBT)ceramics are promising candidates for piezoelectric applications.The correlation between their structure and piezoelectric properties has attracted considerable interest.Herein,the structures of 6BT and 7BT with distinct piezoelectricity are investigated via in-situ synchrotron X-ray diffraction and transmission electron microscopy.It is found that although both compositions present morphotropic phase boundary(MPB)features with coexisting R3c and P4bm phases,their refined structures are significantly different.6BT is composed of the R3c phase with a small P4bm fraction after electrical poling,while 7BT presents comparable fractions of the two phases.Less pronounced structure distortion and oxygen octahedral tilting occur in 7BT,which favor the phase transformation,resulting in an enhanced piezoelectricity.This enhancement driven by structural flexibility is elucidated by phenomenological analysis.These results demonstrate that the design of high piezoelectricity at MPBs should consider not only the phase-coexisting states but also the refined crystal structure.展开更多
Relaxor ferroic dielectrics have garnered increasing attention in the past decade as promising materials for energy storage.Among them,relaxor antiferroelectrics(AFEs)and relaxor ferroelectrics(FEs)have shown great pr...Relaxor ferroic dielectrics have garnered increasing attention in the past decade as promising materials for energy storage.Among them,relaxor antiferroelectrics(AFEs)and relaxor ferroelectrics(FEs)have shown great promise in term of high energy storage density and efficiency,respectively.In this study,a unique phase transition from relaxor AFE to relaxor FE was achieved for the first time by introducing strong-ferroelectricity BaTiO_(3)into NaNbO_(3)-BiFeO_(3)system,leading to an evolution from AFE R hierarchical nanodomains to FE polar nanoregions.A novel medium state,consisting of relaxor AFE and relaxor FE,was identified in the crossover of 0.88NaNbO_(3)–0.07BiFeO_(3)–0.05BaTiO_(3)ceramic,exhibiting a distinctive core-shell grain structure due to the composition segregation.By harnessing the advantages of high energy storage density from relaxor AFE and large efficiency from relaxor FE,the ceramic showcased excellent overall energy storage properties.It achieved a substantial recoverable energy storage density W_(rec)~13.1 J/cm^(3)and an ultrahigh efficiencyη~88.9%.These remarkable values shattered the trade-off relationship typically observed in most dielectric capacitors between W_(rec)andη.The findings of this study provide valuable insights for the design of ceramic capacitors with enhanced performance,specifically targeting the development of next generation pulse power devices.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.21825102,22235002,52172181,and 22105017)Key R&D Plan of the Ministry of Science and Technology of China(Grant No.2022YFB3204000)。
文摘Advanced lead-free energy storage ceramics play an indispensable role in next-generation pulse power capacitors market.Here,an ultrahigh energy storage density of~13.8 J cm^(-3)and a large efficiency of~82.4%are achieved in high-entropy lead-free relaxor ferroelectrics by increasing configuration entropy,named high-entropy strategy,realizing nearly ten times growth of energy storage density compared with low-entropy material.Evolution of energy storage performance and domain structure with increasing configuration entropy is systematically revealed for the first time.The achievement of excellent energy storage properties should be attributed to the enhanced random field,decreased nanodomain size,strong multiple local distortions,and improved breakdown field.Furthermore,the excellent frequency and fatigue stability as well as charge/discharge properties with superior thermal stability are also realized.The significantly enhanced comprehensive energy storage performance by increasing configuration entropy demonstrates that high entropy is an effective but convenient strategy to design new high-performance dielectrics,promoting the development of advanced capacitors.
基金National Key R&D Program of China,Grant/Award Number:2022YFB3204000National Natural Science Foundation of China,Grant/Award Numbers:21825102,22235002,22161142022Fundamental Research Funds for the Central Universities,Grant/Award Number:FRF-IDRY-21-002。
文摘High-performance ferroelectric materials are widely used in various electronic devices owing to the function of mutual conversion among different energies,which mainly relates to their special structure gene of polarization configuration.Recent researches show that the high-entropy strategy has emerged as an effective and flexible approach for boosting physical properties in high-entropy ferroelectrics via the delicate design of local polarization configurations and other intrinsic effects caused by entropy increment,such as entropy stabilization,lattice disorder,inhibition of grain coarsening,improved mechanical properties,cocktail effect,and so on.In this review,the recent research progress about high-entropy ferroelectrics has been summarized,especially for the directional design of novel local polarization configurations according to the characteristics of different electrical properties such as high piezoelectricity,high-efficiency energy storage,and large electrostriction,providing a guidance for designing and exploring more novel local polarization configurations in high-entropy ferroelectrics for generating higher performance.
基金This work was supported by the National Natural Science Foundation of China(grant nos.21825102,and 22075014)the Fundamental Research Funds for the Central Univer-sities,China(FRF-MP-20-40)+1 种基金National Postdoctoral Program for Innovative Talents(BX20200044,and BX20200043)the State Key Lab of Advanced Metals and Materials(2020-ZD01)。
文摘Electrostrictive materials have wide applications in modern high-precision electronic devices.Driven by growing environmental concerns,there is demand for lead-free materials with superior electrostriction behaviors.In this study,we demonstrate a record-high electrostrictive coefficient of~0.0712 m^(4) C^(-2) in perovskite ferroelectric ceramics,along with hysteresis-free strain as well as excellent frequency and thermal stabilities,in lead-free BaTiO_(3)-based ceramics through a polarization nanocluster design.By appro-priately introducing Li+and Bi^(3+)into the BaTiO 3 lattice matrix,the long-range ferroelectric ordering can be broken,and polarization nanoclusters can be formed,resulting in a relaxor state with concurrently suppressed polariza-tion and maintained electro-strain.A three-dimensional atomic model constructed using advanced neutron total-scattering data combined with the reverse Monte Carlo method indicates the existence of Bi and Li segregations at the subnanometer scale,which confirms the prediction made by density functional theory calculations.Such a short-range chemical order destroys the long-range ferroelectric order of the off-centered Ti polar displacements and leads to the embedding of Li+/Bi ^(3+)-rich polar nanoregions in the Ba^(2+)-rich polarization disorder matrix.Further,a completely reversible electric-field-induced lattice strain is observed,giving rise to pure electrostriction without hysteresis behavior.This work provides a novel strategy for developing lead-free relaxor ferroelectrics with high electrostriction performance.
基金supported by the National Natural Science Foundation of China(Grant Nos.22075014,12004032,51972028 and 22001014)China National Postdoctoral Program for Innovative Talents(BX20200044 and BX20200043)+2 种基金China Postdoctoral Science Foundation(2021M690366)the Fundamental Research Funds for the Central Universities,China(Grant Nos.06500162,06500145,and FRF-MP-20-40)a US Department of Energy(DOE)Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No.DEAC02-06CH11357.
文摘Bi_(0.5)Na_(0.5)TiO_(3)-BaTiO_(3)(BNT-100xBT)ceramics are promising candidates for piezoelectric applications.The correlation between their structure and piezoelectric properties has attracted considerable interest.Herein,the structures of 6BT and 7BT with distinct piezoelectricity are investigated via in-situ synchrotron X-ray diffraction and transmission electron microscopy.It is found that although both compositions present morphotropic phase boundary(MPB)features with coexisting R3c and P4bm phases,their refined structures are significantly different.6BT is composed of the R3c phase with a small P4bm fraction after electrical poling,while 7BT presents comparable fractions of the two phases.Less pronounced structure distortion and oxygen octahedral tilting occur in 7BT,which favor the phase transformation,resulting in an enhanced piezoelectricity.This enhancement driven by structural flexibility is elucidated by phenomenological analysis.These results demonstrate that the design of high piezoelectricity at MPBs should consider not only the phase-coexisting states but also the refined crystal structure.
基金financially supported by the National Natural Science Foundation of China(Nos.52172181,22105017)Interdisciplinary Research Project for Young Teachers of USTB(No.FRFIDRY-21–002)。
文摘Relaxor ferroic dielectrics have garnered increasing attention in the past decade as promising materials for energy storage.Among them,relaxor antiferroelectrics(AFEs)and relaxor ferroelectrics(FEs)have shown great promise in term of high energy storage density and efficiency,respectively.In this study,a unique phase transition from relaxor AFE to relaxor FE was achieved for the first time by introducing strong-ferroelectricity BaTiO_(3)into NaNbO_(3)-BiFeO_(3)system,leading to an evolution from AFE R hierarchical nanodomains to FE polar nanoregions.A novel medium state,consisting of relaxor AFE and relaxor FE,was identified in the crossover of 0.88NaNbO_(3)–0.07BiFeO_(3)–0.05BaTiO_(3)ceramic,exhibiting a distinctive core-shell grain structure due to the composition segregation.By harnessing the advantages of high energy storage density from relaxor AFE and large efficiency from relaxor FE,the ceramic showcased excellent overall energy storage properties.It achieved a substantial recoverable energy storage density W_(rec)~13.1 J/cm^(3)and an ultrahigh efficiencyη~88.9%.These remarkable values shattered the trade-off relationship typically observed in most dielectric capacitors between W_(rec)andη.The findings of this study provide valuable insights for the design of ceramic capacitors with enhanced performance,specifically targeting the development of next generation pulse power devices.