Na_(0.5)Bi_(0.5)TiO_(3)(NBT)-based ceramics have been widely used as dielectric materials for energy storage capacitors because of their environmental friendliness and excellent ferroelectric properties.However,their ...Na_(0.5)Bi_(0.5)TiO_(3)(NBT)-based ceramics have been widely used as dielectric materials for energy storage capacitors because of their environmental friendliness and excellent ferroelectric properties.However,their energy storage performance still needs to be further improved to satisfy the increasing demand.Herein,we report a novel 0.90(Na_(0.5)Bi_(0.5))0.7Sr_(0.3)TiO_(3-0.10)Bi(Ni_(0.5)Sn_(0.5))O_(3)(0.90NBST-0.10BNS)ceramic with significantly improved energy density(5.0 J cm3),enhanced recoverable energy density(4.18 J cm^(3))and high energy efficiency(83.64%)through the incorporation of Bi(Ni0.5Sn0.5)O3(BNS),due to the increased breakdown strength and the relaxation ferroelectric(RFE)properties.The first-order reversal curve(FORC)measurements confirm that the addition of BNS improves RFE properties by breaking the order of long-range ferroelectricity.The 0.90NBST-0.10BNS ceramic also possesses an outstanding temperature and frequency stability of energy storage properties in the range of 20C e140C and 1 Hze100 Hz,respectively.More importantly,the discharge properties characterized by a preeminent power density(36.19 MW cm^(3)),transient energy release times(144.2 ns),and high discharge energy density(1.16 J cm3)also synchronously observed in 0.90NBST-0.10BNS ceramic.These results show that the 0.90NBST-0.10BNS ceramic with outstanding comprehensive performances is a promising energy storage ceramic candidate for capacitors in high power systems.展开更多
To reduce the coercive field of Na_(0.5)Bi_(0.5)TiO_(3),Ba TiO_(3)were added as dopant materials.Then the(1-x)Na_(0.5)Bi_(0.5)TiO_(3)-xBaTiO_(3)ceramic samples were produced in solid synthetic way.The optimum preparat...To reduce the coercive field of Na_(0.5)Bi_(0.5)TiO_(3),Ba TiO_(3)were added as dopant materials.Then the(1-x)Na_(0.5)Bi_(0.5)TiO_(3)-xBaTiO_(3)ceramic samples were produced in solid synthetic way.The optimum preparation condition and piezoelectric properties of the samples were investigated.The XRD results show that the fabric transites from rhombohedral to tetragonal gradually with the substitution of the Ba^(2+).The morphotropic phase boundaries(MPB)exists in the composition range of 0.06.展开更多
Na_(0.5)Bi_(0.5)TiO_(3)-based lead-free piezoelectrics are considered for potential replacement of the lead-based commercial piezoceramics in high-power transducer applications.We have examined the role of grain size ...Na_(0.5)Bi_(0.5)TiO_(3)-based lead-free piezoelectrics are considered for potential replacement of the lead-based commercial piezoceramics in high-power transducer applications.We have examined the role of grain size in influencing the structural-polar inhomogeneity of stoichiometric and off-stoichiometric Na_(0.5)Bi_(0.5)TiO_(3)(NBT),and its morphotropic-phase-boundary(MPB)derivative 0.94Na_(0.5)Bi_(0.5)TiO_(3)-0.06BaTiO_(3)(NBT-6BT).Our study reveals that size effect comes into play in these systems on a very large length scale(on the scale of microns)considerably affecting its global structure and properties.展开更多
For efficient solid-state refrigeration technologies based on electrocaloric effect(ECE),it is a great challenge of simultaneously obtaining a large adiabatic temperature change(DT)within a wide temperature span(Tspan...For efficient solid-state refrigeration technologies based on electrocaloric effect(ECE),it is a great challenge of simultaneously obtaining a large adiabatic temperature change(DT)within a wide temperature span(Tspan)in lead-free ferroelectric ceramics.Here,we studied the electrocaloric effect(ECE)in(1-x)(Na_(0.5)Bi_(0.5))TiO_(3)-xCaTiO_(3)((1-x)NBT-xCT)and explored the combining effect of morphotropic phase boundary(MPB)and relaxor feature.The addition of CT not only constructs a MPB region with the coexistence of rhombohedral and orthorhombic phases,but also enhances the relaxor feature.The ECE peak appears around the freezing temperature(Tf),and shifts toward to lower temperature with the increasing CT amount.The directly measured ECE result shows that the ceramic of x=0.10,which is in the MPB region,has an optimal ECE property of DTmax=1.28 K@60℃under 60 kV/cm with a wide Tspan of 65C.The enhanced ECE originates from the electric-field-induced transition between more types of polar nanoregions and long-range ferroelectric macrodomains.For the composition with more relaxor feature in the MPB region,such as x?0.12,the ECE is relatively weak under low electric fields but it exhibits a sharp increment under a sufficiently high electric field.This work provides a guideline to develop the solidestate cooling devices for electronic components.展开更多
Influence of BiFeO_(3)(BF)on phase formation,unit cell parameters,microstructure,dielectric and ferroelectric properties of solid solutions close to the morphotropic phase boundary in the(Na_(0.5)Bi_(0.5))TiO_(3)–(K_...Influence of BiFeO_(3)(BF)on phase formation,unit cell parameters,microstructure,dielectric and ferroelectric properties of solid solutions close to the morphotropic phase boundary in the(Na_(0.5)Bi_(0.5))TiO_(3)–(K_(0.5)Na_(0.5))NbO_(3) system additionally modified by the low-melting KCl additives has been studied.The formation of pure perovskite structure samples decrease in the unit cell parameters and increase in the TC value stimulated by the BF addition have been revealed.It was proved that modification of compositions by small amounts of the BF and KCl additives leads to improvement of dielectric parameters.展开更多
基金The authors sincerely thank the support from the National Natural Science Foundation of China(Grant No.51572159)the Shaanxi Science&Technology Co-ordination&Innovation Project of China(Grant No.2017TSCXL-GY-08-05)the Science Fund for Distinguished Young Scholars of Shaanxi Province(Grant No.2018JC-029).
文摘Na_(0.5)Bi_(0.5)TiO_(3)(NBT)-based ceramics have been widely used as dielectric materials for energy storage capacitors because of their environmental friendliness and excellent ferroelectric properties.However,their energy storage performance still needs to be further improved to satisfy the increasing demand.Herein,we report a novel 0.90(Na_(0.5)Bi_(0.5))0.7Sr_(0.3)TiO_(3-0.10)Bi(Ni_(0.5)Sn_(0.5))O_(3)(0.90NBST-0.10BNS)ceramic with significantly improved energy density(5.0 J cm3),enhanced recoverable energy density(4.18 J cm^(3))and high energy efficiency(83.64%)through the incorporation of Bi(Ni0.5Sn0.5)O3(BNS),due to the increased breakdown strength and the relaxation ferroelectric(RFE)properties.The first-order reversal curve(FORC)measurements confirm that the addition of BNS improves RFE properties by breaking the order of long-range ferroelectricity.The 0.90NBST-0.10BNS ceramic also possesses an outstanding temperature and frequency stability of energy storage properties in the range of 20C e140C and 1 Hze100 Hz,respectively.More importantly,the discharge properties characterized by a preeminent power density(36.19 MW cm^(3)),transient energy release times(144.2 ns),and high discharge energy density(1.16 J cm3)also synchronously observed in 0.90NBST-0.10BNS ceramic.These results show that the 0.90NBST-0.10BNS ceramic with outstanding comprehensive performances is a promising energy storage ceramic candidate for capacitors in high power systems.
基金Funded by the National Natural Science Foundation of China (No.61704113)the Shenzhen Science and Technology Program (No.GJHZ20210705141805015)the Scientific Research Project in School-level (SZIIT2019KJ026)。
文摘To reduce the coercive field of Na_(0.5)Bi_(0.5)TiO_(3),Ba TiO_(3)were added as dopant materials.Then the(1-x)Na_(0.5)Bi_(0.5)TiO_(3)-xBaTiO_(3)ceramic samples were produced in solid synthetic way.The optimum preparation condition and piezoelectric properties of the samples were investigated.The XRD results show that the fabric transites from rhombohedral to tetragonal gradually with the substitution of the Ba^(2+).The morphotropic phase boundaries(MPB)exists in the composition range of 0.06.
文摘Na_(0.5)Bi_(0.5)TiO_(3)-based lead-free piezoelectrics are considered for potential replacement of the lead-based commercial piezoceramics in high-power transducer applications.We have examined the role of grain size in influencing the structural-polar inhomogeneity of stoichiometric and off-stoichiometric Na_(0.5)Bi_(0.5)TiO_(3)(NBT),and its morphotropic-phase-boundary(MPB)derivative 0.94Na_(0.5)Bi_(0.5)TiO_(3)-0.06BaTiO_(3)(NBT-6BT).Our study reveals that size effect comes into play in these systems on a very large length scale(on the scale of microns)considerably affecting its global structure and properties.
基金supported by grants from National Natural Science Foundation of China(52173217)and 111 project(B170003).
文摘For efficient solid-state refrigeration technologies based on electrocaloric effect(ECE),it is a great challenge of simultaneously obtaining a large adiabatic temperature change(DT)within a wide temperature span(Tspan)in lead-free ferroelectric ceramics.Here,we studied the electrocaloric effect(ECE)in(1-x)(Na_(0.5)Bi_(0.5))TiO_(3)-xCaTiO_(3)((1-x)NBT-xCT)and explored the combining effect of morphotropic phase boundary(MPB)and relaxor feature.The addition of CT not only constructs a MPB region with the coexistence of rhombohedral and orthorhombic phases,but also enhances the relaxor feature.The ECE peak appears around the freezing temperature(Tf),and shifts toward to lower temperature with the increasing CT amount.The directly measured ECE result shows that the ceramic of x=0.10,which is in the MPB region,has an optimal ECE property of DTmax=1.28 K@60℃under 60 kV/cm with a wide Tspan of 65C.The enhanced ECE originates from the electric-field-induced transition between more types of polar nanoregions and long-range ferroelectric macrodomains.For the composition with more relaxor feature in the MPB region,such as x?0.12,the ECE is relatively weak under low electric fields but it exhibits a sharp increment under a sufficiently high electric field.This work provides a guideline to develop the solidestate cooling devices for electronic components.
基金The work was supported by the Russian Foundation for Basic Research(Grant 15-03-03269).
文摘Influence of BiFeO_(3)(BF)on phase formation,unit cell parameters,microstructure,dielectric and ferroelectric properties of solid solutions close to the morphotropic phase boundary in the(Na_(0.5)Bi_(0.5))TiO_(3)–(K_(0.5)Na_(0.5))NbO_(3) system additionally modified by the low-melting KCl additives has been studied.The formation of pure perovskite structure samples decrease in the unit cell parameters and increase in the TC value stimulated by the BF addition have been revealed.It was proved that modification of compositions by small amounts of the BF and KCl additives leads to improvement of dielectric parameters.
文摘采用传统固相法制备了(Na0.5Bi0.5)0.6(Bi1-ySry)04TiO3压电陶瓷(记为NBBST-y),利用复阻抗谱分析了电性能,探究了陶瓷中微观组成与电性能的关联.对于NBBST-y压电陶瓷,其晶粒电阻具有典型负温度系数的电阻-温度特性,根据Arrhenius Law拟合计算得到激活能0.574 eV <Ea<0.980 eV,表现为电子导电特征.
