BaTiO_(3)(BT)has attracted extensive attention among advanced lead-free ferroelectric materials due to its unique dielectric and ferroelectric properties.However,the enormous remanent polarization and coercive field s...BaTiO_(3)(BT)has attracted extensive attention among advanced lead-free ferroelectric materials due to its unique dielectric and ferroelectric properties.However,the enormous remanent polarization and coercive field severely impede the improvement of its energy storage capabilities.Here,the BaTiO_(3)e-Bi(Zn_(0.5)Hf_(0.5))O_(3)(BT-BZH)ceramics with high breakdown field strength and remarkable relaxation characteristics can be obtained by introducing the composite component BZH in BT to regulate the phase structure and grain size of the ceramics.The findings demonstrate that the improvement of energy storage performance is related to the increase of relaxation behavior.A large energy storage density(Wrec~3.62 J/cm^(3))along with superior energy storage efficiency(h~88.5%)is achieved in 0.88BT-0.12BZH relaxor ceramics only at 240 kV/cm.In addition,the sample suggests superior thermal stability and frequency stability within 25e115℃and 1e500 Hz,respectively.Furthermore,the outstanding chargedischarge properties with an ultrafast discharge time(100 ns),large discharged energy density(1.2 J/cm^(3)),impressive current density(519.4 A/cm^(2))and power density(31.1 MW/cm^(3))under the electric field of 120 kV/cm are achieved in studied ceramics.The excellent energy storage performance of BT-BZH ceramics provides a promising platform for the application of lead-free energy-storage materials.展开更多
Pb_(x)Sr_(1-x)TiO_(3)(x=0.30,0.35,0.40,0.45,0.50 and 0.55)ceramics were fabricated by a solid-state reaction route.Xeray diffraction data at room temperature show PST samples shift from cubic to tetragonal phase with ...Pb_(x)Sr_(1-x)TiO_(3)(x=0.30,0.35,0.40,0.45,0.50 and 0.55)ceramics were fabricated by a solid-state reaction route.Xeray diffraction data at room temperature show PST samples shift from cubic to tetragonal phase with the increase of Pb^(2+) content.The microstructures were observed by scanning electron microscopy.Dielectric measurement was employed to investigate the ferroelectriceparaelectric phase transition behavior.Temperature dependent polarizationeelectric field hysteresis loops were conducted to study the electrocaloric effect(ECE)of the ferroelectric ceramics by indirect methods over a wide temperature range.Direct measurement of temperature change(DT)at room temperature for all samples can achieve 0.79e1.86 K.What's more,a giant ECE(△T=2.05 K,EC strength(△T/△E)=0.51×10^(-6) K m/V,under 40 kV/cm)was obtained in the sample of x=0.35 near phase transition temperature.Our results suggest that the ceramics are promising cooling materials with excellent EC properties for energy related applications.展开更多
More and more researchers start to pay attention to the electrocaloric temperature change(DT)in polar materials,which is caused by an applied electric field.In this paper,Ba-doped PbHfO_(3)(PBH)films were prepared by ...More and more researchers start to pay attention to the electrocaloric temperature change(DT)in polar materials,which is caused by an applied electric field.In this paper,Ba-doped PbHfO_(3)(PBH)films were prepared by sol-gel method.Their components,microstructures,dielectric polarization and electro-caloric effects(ECEs)were investigated.With the addition of Ba^(2+),PBH films went from antiferroelectric(AFE)to ferroelectric(FE).At the same time,their dielectric peaks shifted toward lower temperature.The maximum DT obtained in Pb_(0.8)Ba_(0.2)HfO_(3)FE film is 41.1 K,which is an order of magnitude larger than PbHfO_(3)film(△T<4 K at 50℃)and Pb_(0.9)Ba_(0.1)HfO_(3)film(△T<4 K at 120℃).In order to explain this phenomenon,the Landau-Devonshire theory was adopted.Our analysis shows that the rapid variation of energy barrier height near the phase transition temperature is beneficial to obtain large polarization change and high△T,which is needed in solid-state cooling devices.展开更多
The development of antiferroelectric materials with large energy density and fast discharge speed makes dielectric capacitors possess great prospects for applications in pulsed power technology.Here,the PbHfO_(3)-base...The development of antiferroelectric materials with large energy density and fast discharge speed makes dielectric capacitors possess great prospects for applications in pulsed power technology.Here,the PbHfO_(3)-based ceramics with compositions of Pb(Hf_(1-x)Ti_(x))O_(3)(PHT,0.01≤x≤0.05)were synthesized,and their antiferroelectricity and phase transition behavior were studied.According to the tests of x-ray diffraction,dielectric spectrum,and polarization-electric field hysteresis loops,PHT ceramics gradually transition from an orthorhombic symmetric antiferroelectric phase to a hexagonal symmetric ferroelectric phase at room temperature as Ti^(4+)concentration increases.The forward phase switching field of antiferroelectric to ferroelectric phase transition can be markedly regulated by the introduction of Ti^(4+),and the optimal energy storage performance was obtained in Pb(Hf_(0.98)Ti_(0.02))O_(3) ceramics with a large recoverable energy storage density of Wrec~4.15 J/cm^(3) and efficiency ofη~65.3%only at a low electric field of 190 kV/cm.Furthermore,the outstanding charge-discharge properties with an ultrafast discharge time(71 ns),remarkable discharged energy density(2.84 J/cm^(3)),impressive current density(1,190 A/cm^(2)),and ultrahigh power density(101 MW/cm^(3))at a low electric field of 170 kV/cm were obtained in studied ceramics.The excellent energy storage performance of PHT ceramics provides a promising platform for the application of dielectric capacitors.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11574057,and 12172093),the Guangdong Basic and Applied Basic Research Foundation(Grant No.2021A1515012607),and the Science and Technology Program of Guangdong Province of China(Grant No.2017A010104022).
文摘BaTiO_(3)(BT)has attracted extensive attention among advanced lead-free ferroelectric materials due to its unique dielectric and ferroelectric properties.However,the enormous remanent polarization and coercive field severely impede the improvement of its energy storage capabilities.Here,the BaTiO_(3)e-Bi(Zn_(0.5)Hf_(0.5))O_(3)(BT-BZH)ceramics with high breakdown field strength and remarkable relaxation characteristics can be obtained by introducing the composite component BZH in BT to regulate the phase structure and grain size of the ceramics.The findings demonstrate that the improvement of energy storage performance is related to the increase of relaxation behavior.A large energy storage density(Wrec~3.62 J/cm^(3))along with superior energy storage efficiency(h~88.5%)is achieved in 0.88BT-0.12BZH relaxor ceramics only at 240 kV/cm.In addition,the sample suggests superior thermal stability and frequency stability within 25e115℃and 1e500 Hz,respectively.Furthermore,the outstanding chargedischarge properties with an ultrafast discharge time(100 ns),large discharged energy density(1.2 J/cm^(3)),impressive current density(519.4 A/cm^(2))and power density(31.1 MW/cm^(3))under the electric field of 120 kV/cm are achieved in studied ceramics.The excellent energy storage performance of BT-BZH ceramics provides a promising platform for the application of lead-free energy-storage materials.
基金the National Natural Science Foundation of China(Grant Nos.11574057 and 51604087)the Guangdong Provincial Natural Science Foundation of China(Grant No.2016A030313718)the Science and Technology Program of Guangdong Province of China(Grant Nos.2016A010104018,and 2017A010104022).
文摘Pb_(x)Sr_(1-x)TiO_(3)(x=0.30,0.35,0.40,0.45,0.50 and 0.55)ceramics were fabricated by a solid-state reaction route.Xeray diffraction data at room temperature show PST samples shift from cubic to tetragonal phase with the increase of Pb^(2+) content.The microstructures were observed by scanning electron microscopy.Dielectric measurement was employed to investigate the ferroelectriceparaelectric phase transition behavior.Temperature dependent polarizationeelectric field hysteresis loops were conducted to study the electrocaloric effect(ECE)of the ferroelectric ceramics by indirect methods over a wide temperature range.Direct measurement of temperature change(DT)at room temperature for all samples can achieve 0.79e1.86 K.What's more,a giant ECE(△T=2.05 K,EC strength(△T/△E)=0.51×10^(-6) K m/V,under 40 kV/cm)was obtained in the sample of x=0.35 near phase transition temperature.Our results suggest that the ceramics are promising cooling materials with excellent EC properties for energy related applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.11574057,12172093,11904056)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2021A1515012607)+1 种基金Guangdong University Research Platform and Research Project in 2022(Grant No.2022KQNCX216)the China Postdoctoral Science Foundation(Grant No.2022T150158).
文摘More and more researchers start to pay attention to the electrocaloric temperature change(DT)in polar materials,which is caused by an applied electric field.In this paper,Ba-doped PbHfO_(3)(PBH)films were prepared by sol-gel method.Their components,microstructures,dielectric polarization and electro-caloric effects(ECEs)were investigated.With the addition of Ba^(2+),PBH films went from antiferroelectric(AFE)to ferroelectric(FE).At the same time,their dielectric peaks shifted toward lower temperature.The maximum DT obtained in Pb_(0.8)Ba_(0.2)HfO_(3)FE film is 41.1 K,which is an order of magnitude larger than PbHfO_(3)film(△T<4 K at 50℃)and Pb_(0.9)Ba_(0.1)HfO_(3)film(△T<4 K at 120℃).In order to explain this phenomenon,the Landau-Devonshire theory was adopted.Our analysis shows that the rapid variation of energy barrier height near the phase transition temperature is beneficial to obtain large polarization change and high△T,which is needed in solid-state cooling devices.
基金National Natural Science Foundation of China(Grant Nos.11574057 and 12172093)Guangdong Basic and Applied Basic Research Foundation(Grant No.2021A1515012607)Science and Technology Program of Guangdong Province of China(Grant No.2017A010104022).
文摘The development of antiferroelectric materials with large energy density and fast discharge speed makes dielectric capacitors possess great prospects for applications in pulsed power technology.Here,the PbHfO_(3)-based ceramics with compositions of Pb(Hf_(1-x)Ti_(x))O_(3)(PHT,0.01≤x≤0.05)were synthesized,and their antiferroelectricity and phase transition behavior were studied.According to the tests of x-ray diffraction,dielectric spectrum,and polarization-electric field hysteresis loops,PHT ceramics gradually transition from an orthorhombic symmetric antiferroelectric phase to a hexagonal symmetric ferroelectric phase at room temperature as Ti^(4+)concentration increases.The forward phase switching field of antiferroelectric to ferroelectric phase transition can be markedly regulated by the introduction of Ti^(4+),and the optimal energy storage performance was obtained in Pb(Hf_(0.98)Ti_(0.02))O_(3) ceramics with a large recoverable energy storage density of Wrec~4.15 J/cm^(3) and efficiency ofη~65.3%only at a low electric field of 190 kV/cm.Furthermore,the outstanding charge-discharge properties with an ultrafast discharge time(71 ns),remarkable discharged energy density(2.84 J/cm^(3)),impressive current density(1,190 A/cm^(2)),and ultrahigh power density(101 MW/cm^(3))at a low electric field of 170 kV/cm were obtained in studied ceramics.The excellent energy storage performance of PHT ceramics provides a promising platform for the application of dielectric capacitors.
