Environmentally friendly antiferroelectric NaNbO,(NN)materials exhibit promising potential in energy storage and electrostrain applications.At room temperature,NN is an antiferroelectric P phase(Space group Pbma)that ...Environmentally friendly antiferroelectric NaNbO,(NN)materials exhibit promising potential in energy storage and electrostrain applications.At room temperature,NN is an antiferroelectric P phase(Space group Pbma)that coexists with a metastable ferroelectric Q phase(Space group P2_(1)ma),so the electric fieldinduced phase transition is irreversible.To stabilize the intrinsic antiferroelectric properties of NNs,phase structure regulation has emerged as a critical research focus.We chose the variable-valence elements Sn and Ce for doping in NN.Through atmospheric sintering,the valence states of the doped ions were altered,resulting in changes in their corresponding substitution positions.This confirmed that the doped ions could be successfully incorporated into the lattice as designed.Importantly,the x=0.04 ceramic exhibited a reversible phase transition between the AFE and FE state resulting in a standard double hysteresis loop at room temperature and a large electrostrain of 0.38%.These findings demonstrat that valence state-controlled co-doping effectively optimizes the antiferroelectric phase stability and functional performance of NN basedmaterials.展开更多
Traditional ferroelectric materials,such as lead zirconate titanate(PZT)ceramics,exhibit positive strain when subjected to an electric field along the polarization direction.In contrast,the piezoelectric polymer polyv...Traditional ferroelectric materials,such as lead zirconate titanate(PZT)ceramics,exhibit positive strain when subjected to an electric field along the polarization direction.In contrast,the piezoelectric polymer polyvinylidene fluoride(PVDF)and its copolymer P(VDF-TrFE)display unique negative strain properties.While extensive research has focused on understanding the origin and mechanisms of this negative strain,limited efforts have been directed toward regulating these properties.This study optimizes the electro-strain and ferroelectric properties of P(VDF-TrFE)piezoelectric films through the synergistic effect of PbTiO_(3)nanosheets and an in-situ electrostatic field.Our results demonstrate that while the incorporation of PbTiO_(3)nanosheets does not notably enhance ferroelectricity,it significantly improves electro-strain properties,particularly negative strain,which increases from-0.097%to-0.185%,an enhancement of 91%.Moreover,the ferroelectric polarization and positive strain of P(VDF-TrFE)are further enhanced under the combined influence of PbTiO_(3)nanosheets and in-situ electrostatic field,increasing maximum polarization from 10.79μmC/cm^(2)to 13.16μmC/cm^(2),a 22%improvement,and positive strain from 0.213%to 0.267%,a 25%enhancement.We propose a possible mechanism for these improvements,attributed to the enhanced flexibility of the amorphous phase and increased content of polar b-phase in P(VDF-TrFE)films under this synergistic effect.This work highlights novel strategies for controlling the electro-strain and ferroelectric properties of P(VDF-TrFE)piezoelectric films.展开更多
This paper investigates a system of 0.93Bi_(0.5)Na_(0.5)TiO_(3)–0.06BaTiO_(3)–0.01K_(0.5)Na_(0.5)NbO_(3)–xCuO(BNT–BT–KNN–xCuO,x=0-0:04 mol.%)ceramics,which were fabricated by the conventional solid-state process...This paper investigates a system of 0.93Bi_(0.5)Na_(0.5)TiO_(3)–0.06BaTiO_(3)–0.01K_(0.5)Na_(0.5)NbO_(3)–xCuO(BNT–BT–KNN–xCuO,x=0-0:04 mol.%)ceramics,which were fabricated by the conventional solid-state process through the granulation of vacuum freeze drier.The results show that the CuO doping made a significant enhancement on the piezoelectric properties of the BNT–BT–KNN ceramics.With the doping of CuO,the transition temperature between ferroelectric phase and ergodic relaxor state is reduced to near room temperature,resulting in pinched P–E loops and“sprout”shape S-E curves.For the composition with x=0.01,a high unipolar strain of 0.39%under 5 kV/mm contributes a large d^(*)33~780 pm/V at room temperature,which is competitive with the other BNT-based ceramics.展开更多
The(1−x)(0.94Bi_(0.5)Na_(0.5)TiO_(3)-0.06BaTiO_(3))-xKTaO_(3)(BNBT-xKT)lead-free ferroelectric ceramics were produced using the traditional solid-state sintering technique,and the phase structure,surface morphology,el...The(1−x)(0.94Bi_(0.5)Na_(0.5)TiO_(3)-0.06BaTiO_(3))-xKTaO_(3)(BNBT-xKT)lead-free ferroelectric ceramics were produced using the traditional solid-state sintering technique,and the phase structure,surface morphology,electrical properties were all thoroughly examined.Every ceramic has a single perovskite structure and there is no second phase,as shown by the XRD patterns and Raman spectra.Scanning electron microscopy revealed that all samples displayed dense microstructure and cubic grain.In addition,KT encourages grain growth due to the oxygen vacancies induced by doping or volatilization of ions at high temperatures.The Tm of the ceramics decreases with increasing doping levels due to oxygen vacancies acting as dipoles upon the addition of KT,and the dielectric loss of all samples is low at ambient temperature.In comparison to the pure BNBT ceramic’s bipolar strain value of 0.12%,the BNBT-2KT ceramic achieved a maximum bipolar strain of~0.506%and unipolar strain of~0.430%with the corresponding d33*up to 538 pm/V under 80 kV/cm field.Performance significantly improved as a result of this.A test of the correlation between temperature and ferroelectric properties shows that the largest strain value of the BNBT-2KT ceramic occurs at ambient temperature and that the phase change from ferroelectric to relaxor is complete.Additionally,it is discovered that the BNBT-3KT ceramic can sustain a stable strain across a broad temperature range,suggesting that it has good temperature stability.The aforementioned findings demonstrate that lead-based ceramics may be replaced with BNBT-xKT ceramics.展开更多
基金sponsored by the Guizhou Tongren University Ph.D.Start-up Fund,China(No.trxyDH2313)Department of Education of Guizhou Province,China(No.QJ[2022]055)+1 种基金Guizhou Key Laboratory of Green Metallurgy and Process Strengthening(No.[2023]026)Jingdezhen University Ph.D.Startup Fund,China(No.jdzxy2502).
文摘Environmentally friendly antiferroelectric NaNbO,(NN)materials exhibit promising potential in energy storage and electrostrain applications.At room temperature,NN is an antiferroelectric P phase(Space group Pbma)that coexists with a metastable ferroelectric Q phase(Space group P2_(1)ma),so the electric fieldinduced phase transition is irreversible.To stabilize the intrinsic antiferroelectric properties of NNs,phase structure regulation has emerged as a critical research focus.We chose the variable-valence elements Sn and Ce for doping in NN.Through atmospheric sintering,the valence states of the doped ions were altered,resulting in changes in their corresponding substitution positions.This confirmed that the doped ions could be successfully incorporated into the lattice as designed.Importantly,the x=0.04 ceramic exhibited a reversible phase transition between the AFE and FE state resulting in a standard double hysteresis loop at room temperature and a large electrostrain of 0.38%.These findings demonstrat that valence state-controlled co-doping effectively optimizes the antiferroelectric phase stability and functional performance of NN basedmaterials.
基金supported by the Zhejiang Provincial Natural Science Foundation(No.LD22E030005,LY22E020005)the“Leading Goose”R&D Program of Zhejiang Province(No.2022C01136)+2 种基金the Joint Funds of the National Science Foundation of China(No.U20A20172)the Fundamental Research Funds for the Central Universities(Grant No.226-2024-00120,226-2024-00188)the Open Research Project of Innovation Center of Yangtze River Delta of Zhejiang University.
文摘Traditional ferroelectric materials,such as lead zirconate titanate(PZT)ceramics,exhibit positive strain when subjected to an electric field along the polarization direction.In contrast,the piezoelectric polymer polyvinylidene fluoride(PVDF)and its copolymer P(VDF-TrFE)display unique negative strain properties.While extensive research has focused on understanding the origin and mechanisms of this negative strain,limited efforts have been directed toward regulating these properties.This study optimizes the electro-strain and ferroelectric properties of P(VDF-TrFE)piezoelectric films through the synergistic effect of PbTiO_(3)nanosheets and an in-situ electrostatic field.Our results demonstrate that while the incorporation of PbTiO_(3)nanosheets does not notably enhance ferroelectricity,it significantly improves electro-strain properties,particularly negative strain,which increases from-0.097%to-0.185%,an enhancement of 91%.Moreover,the ferroelectric polarization and positive strain of P(VDF-TrFE)are further enhanced under the combined influence of PbTiO_(3)nanosheets and in-situ electrostatic field,increasing maximum polarization from 10.79μmC/cm^(2)to 13.16μmC/cm^(2),a 22%improvement,and positive strain from 0.213%to 0.267%,a 25%enhancement.We propose a possible mechanism for these improvements,attributed to the enhanced flexibility of the amorphous phase and increased content of polar b-phase in P(VDF-TrFE)films under this synergistic effect.This work highlights novel strategies for controlling the electro-strain and ferroelectric properties of P(VDF-TrFE)piezoelectric films.
基金This work is financially supported by the National Natural Science Foundation of China(51772204)the State Key Laboratory of New Ceramics and Fine Processing of Tsin-ghua University.
文摘This paper investigates a system of 0.93Bi_(0.5)Na_(0.5)TiO_(3)–0.06BaTiO_(3)–0.01K_(0.5)Na_(0.5)NbO_(3)–xCuO(BNT–BT–KNN–xCuO,x=0-0:04 mol.%)ceramics,which were fabricated by the conventional solid-state process through the granulation of vacuum freeze drier.The results show that the CuO doping made a significant enhancement on the piezoelectric properties of the BNT–BT–KNN ceramics.With the doping of CuO,the transition temperature between ferroelectric phase and ergodic relaxor state is reduced to near room temperature,resulting in pinched P–E loops and“sprout”shape S-E curves.For the composition with x=0.01,a high unipolar strain of 0.39%under 5 kV/mm contributes a large d^(*)33~780 pm/V at room temperature,which is competitive with the other BNT-based ceramics.
基金the financial sponsorship of the National Natural Science Foundation of China(52073235).
文摘The(1−x)(0.94Bi_(0.5)Na_(0.5)TiO_(3)-0.06BaTiO_(3))-xKTaO_(3)(BNBT-xKT)lead-free ferroelectric ceramics were produced using the traditional solid-state sintering technique,and the phase structure,surface morphology,electrical properties were all thoroughly examined.Every ceramic has a single perovskite structure and there is no second phase,as shown by the XRD patterns and Raman spectra.Scanning electron microscopy revealed that all samples displayed dense microstructure and cubic grain.In addition,KT encourages grain growth due to the oxygen vacancies induced by doping or volatilization of ions at high temperatures.The Tm of the ceramics decreases with increasing doping levels due to oxygen vacancies acting as dipoles upon the addition of KT,and the dielectric loss of all samples is low at ambient temperature.In comparison to the pure BNBT ceramic’s bipolar strain value of 0.12%,the BNBT-2KT ceramic achieved a maximum bipolar strain of~0.506%and unipolar strain of~0.430%with the corresponding d33*up to 538 pm/V under 80 kV/cm field.Performance significantly improved as a result of this.A test of the correlation between temperature and ferroelectric properties shows that the largest strain value of the BNBT-2KT ceramic occurs at ambient temperature and that the phase change from ferroelectric to relaxor is complete.Additionally,it is discovered that the BNBT-3KT ceramic can sustain a stable strain across a broad temperature range,suggesting that it has good temperature stability.The aforementioned findings demonstrate that lead-based ceramics may be replaced with BNBT-xKT ceramics.
