Ceramic capacitors designed for energy storage demand both high energy density and efficiency.Achiev-ing a high breakdown strength based on linear dielectrics is of utmost importance.In this study,we present the remar...Ceramic capacitors designed for energy storage demand both high energy density and efficiency.Achiev-ing a high breakdown strength based on linear dielectrics is of utmost importance.In this study,we present the remarkable performance of densely sintered(1-x)(Ca_(0.5)Sr_(0.5)TiO_(3))-xBa_(4)Sm_(28)/3Ti_(18)O_(54) ceramics as energy storage materials,with a measured energy density(Wrec)of 4.9 J/cm^(3)and an ultra-high ef-ficiency(η)of 95%which is almost optimal in linear dielectric that has been reported.To unravel the underlying mechanisms,we conducted a systematic investigation on the influence of adding paraelec-tric Ba_(4)Sm_(28/3)Ti_(18)O_(54)(BST)on both microstructure and macroscopic electrical properties of Ca_(0.5)Sr_(0.5)TiO_(3)(CST).Notably,the addition of BST effectively reduces the grain size of CST.The conduction mechanism is primarily governed by grain boundaries,where high-density grain boundaries act as barriers to charge carrier transport due to their elevated resistivity.Moreover,the activation energy associated with grain boundaries increases with rising resistivity,implying a lower concentration of free vacancies within these regions.The increased barrier height for oxygen vacancy migration at grain boundaries compensates for the grain boundary defects,thereby resulting in enhanced breakdown strength.This characteristic offers a substantial advantage in terms of thermal and frequency stability(25-175℃,1-100 Hz).This work introduces a candidate material with outstanding comprehensive energy storage properties.展开更多
In this work,a novel high entropy perovskite oxide(1-x)(Na_(0.2)Bi_(0.2)Ba_(0.2)Sr_(0.2)Ca_(0.2))TiO_(3-x)NaNbO_(3)(abbrevi-ated as(1-x)NBBSCT-x NN,x=0,0.05,0.1,0.15,and 0.2)was designed to improve temperature dielect...In this work,a novel high entropy perovskite oxide(1-x)(Na_(0.2)Bi_(0.2)Ba_(0.2)Sr_(0.2)Ca_(0.2))TiO_(3-x)NaNbO_(3)(abbrevi-ated as(1-x)NBBSCT-x NN,x=0,0.05,0.1,0.15,and 0.2)was designed to improve temperature dielectric stability and energy storage performance by combining relaxor and antiferroelectric characteristics.The optimal composition of x=0.2 exhibits a high energy storage density of 3.51 J/cm^(3),together with wide temperature stable stability(■<15%,-70 to 110℃),excellent frequency stability(W rec andηvary by only±2.1%and±5.2%within the range of 1-600 Hz)and fast discharge rate(t_(0.9)=55.2 ns).This is mainly due to the enhancement of relaxation behavior and increase of E b caused by the decrease of grain size.These results offer a new strategy for designing high entropy ceramic materials of high performance in the future.展开更多
基金National Natural Science Foundation of China(No.52172118).
文摘Ceramic capacitors designed for energy storage demand both high energy density and efficiency.Achiev-ing a high breakdown strength based on linear dielectrics is of utmost importance.In this study,we present the remarkable performance of densely sintered(1-x)(Ca_(0.5)Sr_(0.5)TiO_(3))-xBa_(4)Sm_(28)/3Ti_(18)O_(54) ceramics as energy storage materials,with a measured energy density(Wrec)of 4.9 J/cm^(3)and an ultra-high ef-ficiency(η)of 95%which is almost optimal in linear dielectric that has been reported.To unravel the underlying mechanisms,we conducted a systematic investigation on the influence of adding paraelec-tric Ba_(4)Sm_(28/3)Ti_(18)O_(54)(BST)on both microstructure and macroscopic electrical properties of Ca_(0.5)Sr_(0.5)TiO_(3)(CST).Notably,the addition of BST effectively reduces the grain size of CST.The conduction mechanism is primarily governed by grain boundaries,where high-density grain boundaries act as barriers to charge carrier transport due to their elevated resistivity.Moreover,the activation energy associated with grain boundaries increases with rising resistivity,implying a lower concentration of free vacancies within these regions.The increased barrier height for oxygen vacancy migration at grain boundaries compensates for the grain boundary defects,thereby resulting in enhanced breakdown strength.This characteristic offers a substantial advantage in terms of thermal and frequency stability(25-175℃,1-100 Hz).This work introduces a candidate material with outstanding comprehensive energy storage properties.
基金This work was financially supported by the National Natural Science Foundation of China(No.52172118).
文摘In this work,a novel high entropy perovskite oxide(1-x)(Na_(0.2)Bi_(0.2)Ba_(0.2)Sr_(0.2)Ca_(0.2))TiO_(3-x)NaNbO_(3)(abbrevi-ated as(1-x)NBBSCT-x NN,x=0,0.05,0.1,0.15,and 0.2)was designed to improve temperature dielectric stability and energy storage performance by combining relaxor and antiferroelectric characteristics.The optimal composition of x=0.2 exhibits a high energy storage density of 3.51 J/cm^(3),together with wide temperature stable stability(■<15%,-70 to 110℃),excellent frequency stability(W rec andηvary by only±2.1%and±5.2%within the range of 1-600 Hz)and fast discharge rate(t_(0.9)=55.2 ns).This is mainly due to the enhancement of relaxation behavior and increase of E b caused by the decrease of grain size.These results offer a new strategy for designing high entropy ceramic materials of high performance in the future.
