Owing to the complex composition architecture of these solid solutions,some fundamental issues of the classical(1-x)(Bi_(1/2)Na_(1/2))TiO_(3) -x(Bi_(1/2)K_(1/2))TiO_(3)(BNT-xBKT)binary system,such as details of phase ...Owing to the complex composition architecture of these solid solutions,some fundamental issues of the classical(1-x)(Bi_(1/2)Na_(1/2))TiO_(3) -x(Bi_(1/2)K_(1/2))TiO_(3)(BNT-xBKT)binary system,such as details of phase evolution and optimal Na/K ratio associated with the highest strain responses,remain unresolved.In this work,we systematically investigated the phase evolution of the BNT-xBKT binary solid solution with x ranging from 0.12 to 0.24 using not only routine X-ray diffraction and weak-signal dielectric characterization,but also temperature-dependent polarization versus electric field(P-E)and current versus electric field(I-E)curves.Our results indicate an optimal Na/K ratio of 81/19 based on high-field polarization and elec-trostrain characterizations.As the temperature increased above 100?C,the x¼0.19 composition pro-duces ultrahigh electrostrains(>0.5%)with high thermal stability.The ultrahigh and stable electrostrains were primarily due to the combined effect of electric-field-induced relaxor-to-ferroelectric phase tran-sition and ferroelectric-to-relaxor diffuse phase transition during heating.More specifically,we revealed the relationship between phase evolution and electrostrain responses based on the characteristic tem-peratures determined by both weak-field dielectric and high-field ferroelectric/electromechanical property characterizations.This work not only clarifies the phase evolution in BNT-xBKT binary solid solution,but also paves the way for future strain enhancement through doping strategies.展开更多
3Lead-free(BiasNaus)TiO_(3)(BNT)-based relaxor ferroelectric(RFE)ceramics have attracted a lot of atten-tion due to their high power density and rapid charge-discharge apabilities,as well as their potential applicatio...3Lead-free(BiasNaus)TiO_(3)(BNT)-based relaxor ferroelectric(RFE)ceramics have attracted a lot of atten-tion due to their high power density and rapid charge-discharge apabilities,as well as their potential application in pulse power capacitors.However,because of the desire for smaller electronic devices,their energy storage performance(ESP)should be enhanced even further.We describe a defect engineering strategy for enhancing the antiferroelectric-like RFE feature of BNT-based ceramics by unequal substi-tution of rare-earth La^(3+)in this paper.The ESP of La^(3+)-doped samples is raised by 25%with the same synthetic procedure and thidkness,due to an inrease in the critical electric field(E-field)and saturated E-field during polarization response,which is induced by a modifiation in the energy barrier between the lattice torsion.More impressively,an ultrahigh recoverable energy storage density Wrec of 8.58J/cm^(3)and a high energy storage efficiengyηof 945%are simultaneously attained in 3 at.%La^(3+)-substituted 0.6(Bi_(0.5)Na_(0.4)K_(0.1))_(1-1.5x)La_(x)TiO_(3)-0.4[2/3SrTiO_(3)-1/3Bi(Mg_(2/3)Ni_(1/3))O_(3)]RFE ceamics with good temperatue stability(W_(rec)=4.6±0.2 J/cm^(3)and higher n of 290%from 30℃to 120℃),frequency stability,and fatigue resistance.The significant inrease in ESP achieved through defect engineering not only proves the effectiveness of our strategy,but also presents a novel dielectric material with potential applications in pulse power apacitors.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51772239 and 51761145024)the Fundamental Research Funds for the Central Universities(XJTU)。
文摘Owing to the complex composition architecture of these solid solutions,some fundamental issues of the classical(1-x)(Bi_(1/2)Na_(1/2))TiO_(3) -x(Bi_(1/2)K_(1/2))TiO_(3)(BNT-xBKT)binary system,such as details of phase evolution and optimal Na/K ratio associated with the highest strain responses,remain unresolved.In this work,we systematically investigated the phase evolution of the BNT-xBKT binary solid solution with x ranging from 0.12 to 0.24 using not only routine X-ray diffraction and weak-signal dielectric characterization,but also temperature-dependent polarization versus electric field(P-E)and current versus electric field(I-E)curves.Our results indicate an optimal Na/K ratio of 81/19 based on high-field polarization and elec-trostrain characterizations.As the temperature increased above 100?C,the x¼0.19 composition pro-duces ultrahigh electrostrains(>0.5%)with high thermal stability.The ultrahigh and stable electrostrains were primarily due to the combined effect of electric-field-induced relaxor-to-ferroelectric phase tran-sition and ferroelectric-to-relaxor diffuse phase transition during heating.More specifically,we revealed the relationship between phase evolution and electrostrain responses based on the characteristic tem-peratures determined by both weak-field dielectric and high-field ferroelectric/electromechanical property characterizations.This work not only clarifies the phase evolution in BNT-xBKT binary solid solution,but also paves the way for future strain enhancement through doping strategies.
基金This work was supported by the National Natural Science Foundation of China(Grant No.52172127)the National Key R&D Program of China(Grant Nos.2021YFE0115000 and SQ2021YFB380003202)the Fundamental Research Funds for the Central Universities(XJTU).The SEM work was done at International Center for Dielectric Research(ICDR),Xi’an Jiaotong University,Xi'an,China.
文摘3Lead-free(BiasNaus)TiO_(3)(BNT)-based relaxor ferroelectric(RFE)ceramics have attracted a lot of atten-tion due to their high power density and rapid charge-discharge apabilities,as well as their potential application in pulse power capacitors.However,because of the desire for smaller electronic devices,their energy storage performance(ESP)should be enhanced even further.We describe a defect engineering strategy for enhancing the antiferroelectric-like RFE feature of BNT-based ceramics by unequal substi-tution of rare-earth La^(3+)in this paper.The ESP of La^(3+)-doped samples is raised by 25%with the same synthetic procedure and thidkness,due to an inrease in the critical electric field(E-field)and saturated E-field during polarization response,which is induced by a modifiation in the energy barrier between the lattice torsion.More impressively,an ultrahigh recoverable energy storage density Wrec of 8.58J/cm^(3)and a high energy storage efficiengyηof 945%are simultaneously attained in 3 at.%La^(3+)-substituted 0.6(Bi_(0.5)Na_(0.4)K_(0.1))_(1-1.5x)La_(x)TiO_(3)-0.4[2/3SrTiO_(3)-1/3Bi(Mg_(2/3)Ni_(1/3))O_(3)]RFE ceamics with good temperatue stability(W_(rec)=4.6±0.2 J/cm^(3)and higher n of 290%from 30℃to 120℃),frequency stability,and fatigue resistance.The significant inrease in ESP achieved through defect engineering not only proves the effectiveness of our strategy,but also presents a novel dielectric material with potential applications in pulse power apacitors.