A high breakdown strength(E_(b))together with a large maximum polarization(P_(m))is essential for achieving a high recoverable energy density(W_(rec))in energy storage dielectric ceramics.However,meeting the urgent ne...A high breakdown strength(E_(b))together with a large maximum polarization(P_(m))is essential for achieving a high recoverable energy density(W_(rec))in energy storage dielectric ceramics.However,meeting the urgent need for practical applications remains a challenge due to the intrinsic properties of bulk dielectric ceramics.Herein,a composition and structure optimization strategy combined with a two-step sintering(TSS)process is proposed to design and fabricate(1−x)Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.9)O_(3−x)Bi(Mg_(1/2)Sn_(1/2))O_(3)(BCZT-BMSx-TSS)lead-free ceramics.Highly dynamic locally polar nano-regions(PNRs)are formed via composition optimization,exhibiting a very high P_(m) and energy storage efficiency(η).Compared to the traditional one-step sintering(OSS)process,the TSS process results in a composition with finer grain size and higher density,dramatically increasing E_(b).As a result,an ultrahigh energy storage performance with W_(rec)∼10.53 J cm^(−3) and η∼85.71%is achieved for the BCZT-BMSx-TSS(x=0.08)ceramic which is attributed to a record high E_(b)∼830 kV cm^(−1) and a large P_(m)∼44.66μC cm^(−2).Complex impedance spectroscopy revealed that the activation energies of the bulk and grain boundary counterparts significantly increased,suggesting an increase in insulation resistance and a decrease in oxygen vacancies,which is the main reason for the high E_(b) value.In addition,excellent thermal/frequency stability is achieved in both energy density and efficiency,along with good charge–discharge performance.These findings suggest that BCZT-based lead-free ceramics have the potential for practical use in the future.展开更多
Based on the fundamentals of energy storage capacitors,recoverable energy storage density(Wrec)is greatly dependent on breakdown strength(Eb).In this work,the breakdown performance of 0.92Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_...Based on the fundamentals of energy storage capacitors,recoverable energy storage density(Wrec)is greatly dependent on breakdown strength(Eb).In this work,the breakdown performance of 0.92Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.9)O_(3)-0.08Bi_(2/3)(M_(1/3)Ta_(2/3))O_(3)(M=Mg and Zn)is significantly improved through the synergistic effect of defect chemistry and energy band engineering.The addition of A-site deficient Bi_(2/3)(M_(1/3)Ta_(2/3))O_(3)triggers a ferroelectric-to-relaxor ferroelectric phase transition,leading to the formation of local polar nano-regions(PNRs).More importantly,the introduction of Bi_(2/3)(M_(1/3)Ta_(2/3))O_(3)into Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.9)O_(3)effectively increases the band gap of samples and reduces grain growth and leakage current density by inhibiting the formation of oxygen vacancies,thus enhancing Eb.As a result,an ultrahigh Eb of~681.7 kV cm^(-1) for the 0.92Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.9)O_(3)-0.08Bi_(2/3)(Zn_(1/3)Ta_(2/3))O_(3)ceramic accompanied by a large maximum polarization(~31.6μC cm^(-2))contributes to a high Wrec of~6.93 J cm^(-3) and efficiency of~82%.Furthermore,all these ceramics exhibited excellent thermal/frequency stability and charge-discharge performances.These findings suggest that defect chemistry and energy band engineering is an effective strategy for developing novel lead-free relaxor ferroelectric ceramics.展开更多
基金supported by the Projects of the Jilin Provincial Science and Technology Department(Grant No.YDZJ202201ZYTS420)the Projects of the Jilin Provincial Education Department(Grant No.JJKH20230298KJ)the National Science Foundation for Yong Scientists China(Grant No.62004081).
文摘A high breakdown strength(E_(b))together with a large maximum polarization(P_(m))is essential for achieving a high recoverable energy density(W_(rec))in energy storage dielectric ceramics.However,meeting the urgent need for practical applications remains a challenge due to the intrinsic properties of bulk dielectric ceramics.Herein,a composition and structure optimization strategy combined with a two-step sintering(TSS)process is proposed to design and fabricate(1−x)Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.9)O_(3−x)Bi(Mg_(1/2)Sn_(1/2))O_(3)(BCZT-BMSx-TSS)lead-free ceramics.Highly dynamic locally polar nano-regions(PNRs)are formed via composition optimization,exhibiting a very high P_(m) and energy storage efficiency(η).Compared to the traditional one-step sintering(OSS)process,the TSS process results in a composition with finer grain size and higher density,dramatically increasing E_(b).As a result,an ultrahigh energy storage performance with W_(rec)∼10.53 J cm^(−3) and η∼85.71%is achieved for the BCZT-BMSx-TSS(x=0.08)ceramic which is attributed to a record high E_(b)∼830 kV cm^(−1) and a large P_(m)∼44.66μC cm^(−2).Complex impedance spectroscopy revealed that the activation energies of the bulk and grain boundary counterparts significantly increased,suggesting an increase in insulation resistance and a decrease in oxygen vacancies,which is the main reason for the high E_(b) value.In addition,excellent thermal/frequency stability is achieved in both energy density and efficiency,along with good charge–discharge performance.These findings suggest that BCZT-based lead-free ceramics have the potential for practical use in the future.
基金supported by the National Science Foundation for Yong Scientists China(Grant No.62004081)the Projects of Jilin Provincial Science and Technology Department(Grant No.YDZJ202201ZYTS420)Projects of the Jilin Provincial Education Department(Grant No.JJKH_(2)0230298KJ and JJKH_(2)0230301KJ).
文摘Based on the fundamentals of energy storage capacitors,recoverable energy storage density(Wrec)is greatly dependent on breakdown strength(Eb).In this work,the breakdown performance of 0.92Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.9)O_(3)-0.08Bi_(2/3)(M_(1/3)Ta_(2/3))O_(3)(M=Mg and Zn)is significantly improved through the synergistic effect of defect chemistry and energy band engineering.The addition of A-site deficient Bi_(2/3)(M_(1/3)Ta_(2/3))O_(3)triggers a ferroelectric-to-relaxor ferroelectric phase transition,leading to the formation of local polar nano-regions(PNRs).More importantly,the introduction of Bi_(2/3)(M_(1/3)Ta_(2/3))O_(3)into Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.9)O_(3)effectively increases the band gap of samples and reduces grain growth and leakage current density by inhibiting the formation of oxygen vacancies,thus enhancing Eb.As a result,an ultrahigh Eb of~681.7 kV cm^(-1) for the 0.92Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.9)O_(3)-0.08Bi_(2/3)(Zn_(1/3)Ta_(2/3))O_(3)ceramic accompanied by a large maximum polarization(~31.6μC cm^(-2))contributes to a high Wrec of~6.93 J cm^(-3) and efficiency of~82%.Furthermore,all these ceramics exhibited excellent thermal/frequency stability and charge-discharge performances.These findings suggest that defect chemistry and energy band engineering is an effective strategy for developing novel lead-free relaxor ferroelectric ceramics.
