Controlling Li ion transport in glasses at atomic and molecular levels is key to realizing all-solid-state batteries,a promising technology for electric vehicles.In this context,Li_(3)PS_(4)glass,a promising solid ele...Controlling Li ion transport in glasses at atomic and molecular levels is key to realizing all-solid-state batteries,a promising technology for electric vehicles.In this context,Li_(3)PS_(4)glass,a promising solid electrolyte candidate,exhibits dynamic coupling between the Li^(+)cation mobility and the PS_(4)^(3-)anion libration,which is commonly referred to as the paddlewheel effect.In addition,it exhibits a concerted cation diffusion effect(i.e.,a cation-cation interaction),which is regarded as the essence of high Li ion transport.However,the correlation between the Li^(+)ions within the glass structure can only be vaguely determined,due to the limited experimental information that can be obtained.Here,this study reports that the Li ions present in glasses can be classified by evaluating their valence oscillations via Bader analysis to topologically analyze the chemical bonds.It is found that three types of Li ions are present in Li_(3)PS_(4)glass,and that the more mobile Li ions(i.e.,the Li3-type ions)exhibit a characteristic correlation at relatively long distances of 4.0-5.0A.Furthermore,reverse Monte Carlo simulations combined with deep learning potentials that reproduce X-ray,neutron,and electron diffraction pair distribution functions showed an increase in the number of Li3-type ions for partially crystallized glass structures with improved Li ion transport properties.Our results show order within the disorder of the Li ion distribution in the glass by a topological analysis of their valences.Thus,considering the molecular vibrations in the glass during the evaluation of the Li ion valences is expected to lead to the development of new solid electrolytes.展开更多
Simultaneous ultrasonic elastic wave velocity and in situ synchrotron X-ray measurements on grossular garnet were carried out up to 17 GPa and 1 650 K. P- and S-wave vdoeities and bulk and shear modulus showed linear ...Simultaneous ultrasonic elastic wave velocity and in situ synchrotron X-ray measurements on grossular garnet were carried out up to 17 GPa and 1 650 K. P- and S-wave vdoeities and bulk and shear modulus showed linear pressure and temperature dependence. These data yielded a pressure derivative of the bulk modulus of 4.42（7） and a shear modulus of 1.27（3）, which are in good agreement with those of garnets with variable chemical compositions. Temperature dependence of the bulk modulus of grossular （-1.36×10^-2 GPafK） is also similar to that of other garnets, while the temperature dependence of the shear modulus of grossular （-1.11×10^-2 GPa/K） is higher than those of magnesium end-member garnets and pyrolitic garnet.展开更多
Synchrotron radiation x-ray diffraction investigations of iron(Fe)and nickel(Ni)are conducted at pressures up to 354 and 368 GPa,respectively,and the equations of state(EOSs)at 298 K for the two elements are obtained ...Synchrotron radiation x-ray diffraction investigations of iron(Fe)and nickel(Ni)are conducted at pressures up to 354 and 368 GPa,respectively,and the equations of state(EOSs)at 298 K for the two elements are obtained for data extending to pressures as high as those at the center of the Earth,using the latest Pt-EOS pressure scale.From a least-squares fit to the Vinet equation using the observed pressure–volume data,the isothermal bulk modulus K0 and its pressure derivative K′0 are estimated to be 159.27(99)GPa and 5.86(4)for hcp-Fe,and 173.5(1.4)GPa and 5.55(5)for Ni.By comparing the present EOSs and extrapolated EOSs reported in the literature for Fe and Ni,the volumes of Fe and Ni at 365 GPa are found to be 2.3%and 1.5%larger than those estimated from extrapolated EOSs in previous studies,respectively.It is concluded that these discrepancies are due to the pressure scale.The present results suggest that the densities of Fe and Ni at a pressure of 365 GPa corresponding to the center of the Earth are 2.3%and 1.5%,respectively,lower than previously thought.展开更多
Gold clusters and small nanoparticles supported on metal oxides could be prepared by deposition‐precipitation followed by microwave irradiation as a drying method and then calcination.The drying method influenced the...Gold clusters and small nanoparticles supported on metal oxides could be prepared by deposition‐precipitation followed by microwave irradiation as a drying method and then calcination.The drying method influenced the size of the Au particles.Au(III)was partly reduced during conventional oven drying,resulting in Au aggregates.In contrast,Au(III)was preserved during microwave drying owing to rapid and uniform heating,and the Au diameter was minimized to1.4nm on Al2O3.This method can be applied to several metal oxide supports having different microwave absorption efficiencies,such as MnO2,Al2O3,and TiO2.These catalysts exhibited higher catalytic activities for CO oxidation at low temperature and for selective aerobic oxidation of sulfide than those prepared by conventional methods.展开更多
The uncontrollable Li electrostripping and plating process that results in dendritic Li growth and huge volume change of Li anode limits the practicality of Li metal batteries(LMBs).To simultaneously address these iss...The uncontrollable Li electrostripping and plating process that results in dendritic Li growth and huge volume change of Li anode limits the practicality of Li metal batteries(LMBs).To simultaneously address these issues,designing three-dimensional(3D),lithiophilic and mechanically robust electrodes seems to be one of the cost-effective strategies.Herein,a new 3D Li-B-C-Al alloy anode is designed and fabricated.The prepared 3D alloy anode exhibits not only superior lithiophilicity that facilitates uniform Li nucleation and growth but also sufficient mechanical stability that maintains its structural integrity.Superior performance of the prepared 3D alloy is demonstrated through comprehensive electrochemical tests.In addition,non-destructive and 3D synchrotron X-ray computed tomography(SX-CT)technique is employed to investigate the underlying working mechanisms of the prepared alloy anode.A unique twofold Li electrostripping and plating mechanism under different electrochemical cycling conditions is revealed.Lastly,improved performance of the full cells built with the 3D alloy anode and LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cathode corroborate its potential application capability.Overall,the current work not only showcases the superiority of the 3D alloy as potential anode material for LMBs but also provides fundamental insights into its underlying working mechanisms that may further propel its research and development.展开更多
The early Cambrian pentamerous microfossil Olivooides/Punctatus in South China, which is characterized by a diagnostic stellate tubular apex, has been well-known for its almost complete development sequence that can b...The early Cambrian pentamerous microfossil Olivooides/Punctatus in South China, which is characterized by a diagnostic stellate tubular apex, has been well-known for its almost complete development sequence that can be confidently traced from embryos and hatched juveniles, to conical adults. However, its zoological affinity remains highly controversial. Here we describe the internal microanatomic structures of the soft-body inside the peridermal theca of Olivooides multisulcatus Qian, 1977, including interradial pairs of tentacles, adradial and perradial frenula, perradial oral marginal lappets and twins of perradial gastric saccule-like humps as well as a circular velarium with striated coronal muscles. Particularly, one specimen shows bifurcated velarial canals along the bell aperture. Both the components of the soft-body and the external theca （or cyst） are arranged in perfect pentaradial symmetry. These characteristics are more compatible with those of living cubomedusans and co-occurring Cambrian athecate embryonic cubozoans. Concerning the presence of peridermal theca, Olivooides most likely represents an extinct thecate stem-group cubomedusae but devoid of both perradial eyes and specialized pedalia. The well-grown soft body inside the peridermal tube displays a set of mixed features of both polyp and medusa.展开更多
Lead dissolved in water must be removed in order not to cause diseases, especially from high pH aqueous solution. Various oxides having high specific surface area are often applied to remove lead in water media. To im...Lead dissolved in water must be removed in order not to cause diseases, especially from high pH aqueous solution. Various oxides having high specific surface area are often applied to remove lead in water media. To improve removal ability for lead species, it is necessary to understand the adsorbed structure of lead species on oxides. At first, the adsorption behavior of lead from high pH solution in the presence of Ca<sup>2+</sup> and Na+ was compared. Lead and calcium species were adsorbed up to the monolayer, and the adsorption isotherm was analyzed as Langmuir-type adsorption. In the presence of Ca<sup>2+</sup>, the amount of removed lead was reduced. To clarify this influence of Ca<sup>2+</sup>, X-ray absorption spectroscopy was adopted. It was for the first time revealed that lead species at pH > 12 and pH < 10.5 differed, and that lead species adsorbed on various oxides had a similar structure.展开更多
Negative thermal expansion(NTE)is fascinating,as it involves a material’s volume contraction rather than expansion upon heating.Although NTE lattices typically have highly flexible frameworks,the magnitude of NTE is ...Negative thermal expansion(NTE)is fascinating,as it involves a material’s volume contraction rather than expansion upon heating.Although NTE lattices typically have highly flexible frameworks,the magnitude of NTE is often very small,and they frequently exhibit a narrow temperature range for controllable NTEs.It remains a great challenge to achieve large NTE while maintaining a wide temperature operation range from the currently available materials.Herein,we present a novel PbTiO_(3)(PT)-based perovskite system,(1−x)PbTiO_(3)-xBiYbO_(3),synthesized via a distinctive highpressure and high-temperature technique.Compared with pristine PbTiO_(3)(c/a=1.064),the system exhibited unusual enhanced tetragonalities.Consequently,NTE over an extended temperatureαVαVαV range has been realized in 0.95PbTiO_(3)-0.05BiYbO_(3)(-av=−2.18×10^(−5)K^(−1),300-820 K)and 0.90PbTiO_(3)−0.10BiYbO_(3)(-av=−1.85×10^(−5)K^(−1),300-850 K)compared with that of pristine PbTiO_(3)(-av=−1.99×10^(−5)K^(−1),300-763 K).Our experimental and theoretical studies indicate that the improved tetragonality and expanded NTE temperature range result from larger ionic displacements and an enhanced asymmetric charge distribution,both of which are induced by BiYbO_(3) substitution.The present study presents a new example of an NTE across a broad temperature range,highlighting its potential as an effective thermal expansion compensator.展开更多
Negative thermal expansion(NTE)is a notable physical property where a material’s volume decreases instead of increasing when heated.The identification of NTE materials is crucial for thermal expansion control enginee...Negative thermal expansion(NTE)is a notable physical property where a material’s volume decreases instead of increasing when heated.The identification of NTE materials is crucial for thermal expansion control engineering.Most NTE materials exhibit NTE only within a narrow temperature range,restricting their applications.Achieving NTE across a broad temperature range remains a significant challenge.This study developed a novel PbTiO_(3)-based system,(1-x)PbTiO_(3–x)BiLuO_(3),incorporating rare-earth elements,using a distinctive high-pressure and high-temperature synthesis technique.We achieved NTE across a broad temperature range by coupling lattice(c/a)with ferroelectric order parameters.The incorporation of BiLuO_(3)resulted in distinctive ferroelectric characteristics,including increased tetragonality,spontaneous polarization,and NTE over a broad temperature range.NTE over an extended temperature range has been achieved in 0.95PbTiO_(3)–0.05BiLuO_(3)(■=−1.7×10^(–5)K^(−1),300–840 K)and 0.90PbTiO_(3)–0.10BiLuO_(3)(■=−1.4×10^(–5)K^(−1),300–860 K),compared to pristine PbTiO_(3)(■=−1.99×10^(–5)K^(−1),300–763 K).The improved tetragonalities and broader NTE temperature range result from the strong hybridization of Pb/Bi–O and Ti/Lu–O atoms,as demonstrated by combined experimental and theoretical analyses,including high-energy synchrotron X-ray diffraction,Raman spectroscopy,and density functional theory calculations.This study introduces a novel example of NTE over a broad temperature range,highlighting its potential as a high-performance thermal expansion compensator.Additionally,it presents an effective method for incorporating rare-earth elements to achieve NTE in PbTiO_(3)-based perovskites across a wide temperature range.展开更多
With exceptional capacity during high-voltage cycling,P3-type Nadeficient layered oxide cathodes have captured substantial attention.Nevertheless,they are plagued by severe capacity degradation over cycling.In this st...With exceptional capacity during high-voltage cycling,P3-type Nadeficient layered oxide cathodes have captured substantial attention.Nevertheless,they are plagued by severe capacity degradation over cycling.In this study,tuning and optimizing the phase composition in layered oxides through Li incorporation are proposed to enhance the high-voltage stability.The structural dependence of layered Na_(2/3)LixNi_(0.25)Mn_(0.75)O_(2)þδoxides on the lithium content(0.0≤x≤1.0)offered during synthesis is investigated systematically on an atomic scale.Surprisingly,increasing the Li content triggers the formation of mixed P2/O3-type or P3/P2/O3-type layered phases.As the voltage window is 1.5-4.5 V,P3-type Na2/3Ni_(0.25)Mn_(0.75)O_(2)(NL0.0NMO,R3m)material exhibits a sequence of phase transformations throughout the process of(de)sodiation,that is,O3⇌P3⇌O30⇌O3″.Such complicated phase transitions can be effectively suppressed in the Na2/3Li_(0.7)Ni_(0.25)Mn_(0.75)O_(2.4)(NL_(0.7)NMO)oxide with P2/P3/O3-type mixed phases.Consequently,cathodes made of NL0.7NMO exhibit a substantially enhanced cyclic performance at high voltages compared to that of the P3-type layered NL0.0NMO cathode.Specifically,NL0.7NMO demonstrates an outstanding capacity retention of 98%after 10 cycles at 1 C within 1.5-4.5 V,much higher than that of NL0.0NMO(83%).This work delves into the intricate realm of bolstering the high-voltage durability of layered oxide cathodes,paving the way for advanced sodium-ion battery technologies.展开更多
High-performance all-solid-state lithium-ion batteries require observation,control,and optimization of the electrode structure.X-ray computational tomography(CT)is an effective nondestructive method for observing the ...High-performance all-solid-state lithium-ion batteries require observation,control,and optimization of the electrode structure.X-ray computational tomography(CT)is an effective nondestructive method for observing the electrode structure in three dimensions.However,the limited availability of synchrotron radiation CT,which offers high-resolution imaging with a high signal-to-noise ratio,makes it difficult to conduct experiments and restricts the use of X-ray CT in battery development.Conversely,laboratory CT systems are widely available,but they use X-rays emitted from a metal target,resulting in lower image quality and resolution compared with synchrotron radiation CT.This study explores a method for achieving comparable resolution in laboratory CT images of all-solid-state batteries to that of synchrotron radiation CT.Our method involves using the synchrotron radiation CT images as training data for machine learning super-resolution.The results demonstrate that,by employing an appropriate machine learning algorithm and activation function,along with a sufficiently deep network,the image quality of laboratory CT becomes equivalent to that of synchrotron radiation CT.展开更多
基金partially supported by JSPS KAKENHI(Grant Numbers 19 K05025,19H05814,19H05815,19H05816,20H02430,21H02038,and 21H05549)
文摘Controlling Li ion transport in glasses at atomic and molecular levels is key to realizing all-solid-state batteries,a promising technology for electric vehicles.In this context,Li_(3)PS_(4)glass,a promising solid electrolyte candidate,exhibits dynamic coupling between the Li^(+)cation mobility and the PS_(4)^(3-)anion libration,which is commonly referred to as the paddlewheel effect.In addition,it exhibits a concerted cation diffusion effect(i.e.,a cation-cation interaction),which is regarded as the essence of high Li ion transport.However,the correlation between the Li^(+)ions within the glass structure can only be vaguely determined,due to the limited experimental information that can be obtained.Here,this study reports that the Li ions present in glasses can be classified by evaluating their valence oscillations via Bader analysis to topologically analyze the chemical bonds.It is found that three types of Li ions are present in Li_(3)PS_(4)glass,and that the more mobile Li ions(i.e.,the Li3-type ions)exhibit a characteristic correlation at relatively long distances of 4.0-5.0A.Furthermore,reverse Monte Carlo simulations combined with deep learning potentials that reproduce X-ray,neutron,and electron diffraction pair distribution functions showed an increase in the number of Li3-type ions for partially crystallized glass structures with improved Li ion transport properties.Our results show order within the disorder of the Li ion distribution in the glass by a topological analysis of their valences.Thus,considering the molecular vibrations in the glass during the evaluation of the Li ion valences is expected to lead to the development of new solid electrolytes.
基金supported by the research proposal to SPring-8 by Y Kono (No. 2007B1648)the Grant-in-Aid for Scientific Research from the Japanese Government to T Irifune
文摘Simultaneous ultrasonic elastic wave velocity and in situ synchrotron X-ray measurements on grossular garnet were carried out up to 17 GPa and 1 650 K. P- and S-wave vdoeities and bulk and shear modulus showed linear pressure and temperature dependence. These data yielded a pressure derivative of the bulk modulus of 4.42（7） and a shear modulus of 1.27（3）, which are in good agreement with those of garnets with variable chemical compositions. Temperature dependence of the bulk modulus of grossular （-1.36×10^-2 GPafK） is also similar to that of other garnets, while the temperature dependence of the shear modulus of grossular （-1.11×10^-2 GPa/K） is higher than those of magnesium end-member garnets and pyrolitic garnet.
基金JSPS KAKENHI Grant Nos.JP17·6708,JP19740332,and JP19K04051 to N.H.and Grant No.JP17K05550 to Y.A.the SPring-8 facility with the approval of the JASRI(Proposal Nos.2005B0272,2005B0307,2006A1077,2006A1307,2006A1792,2007A1277,2007A1286,2008B1247,2009A1444,2018B1144,and 2020A1194).
文摘Synchrotron radiation x-ray diffraction investigations of iron(Fe)and nickel(Ni)are conducted at pressures up to 354 and 368 GPa,respectively,and the equations of state(EOSs)at 298 K for the two elements are obtained for data extending to pressures as high as those at the center of the Earth,using the latest Pt-EOS pressure scale.From a least-squares fit to the Vinet equation using the observed pressure–volume data,the isothermal bulk modulus K0 and its pressure derivative K′0 are estimated to be 159.27(99)GPa and 5.86(4)for hcp-Fe,and 173.5(1.4)GPa and 5.55(5)for Ni.By comparing the present EOSs and extrapolated EOSs reported in the literature for Fe and Ni,the volumes of Fe and Ni at 365 GPa are found to be 2.3%and 1.5%larger than those estimated from extrapolated EOSs in previous studies,respectively.It is concluded that these discrepancies are due to the pressure scale.The present results suggest that the densities of Fe and Ni at a pressure of 365 GPa corresponding to the center of the Earth are 2.3%and 1.5%,respectively,lower than previously thought.
基金supported by JSPS KAKENHI Grant Numbers JP26810098 and JP16K17943~~
文摘Gold clusters and small nanoparticles supported on metal oxides could be prepared by deposition‐precipitation followed by microwave irradiation as a drying method and then calcination.The drying method influenced the size of the Au particles.Au(III)was partly reduced during conventional oven drying,resulting in Au aggregates.In contrast,Au(III)was preserved during microwave drying owing to rapid and uniform heating,and the Au diameter was minimized to1.4nm on Al2O3.This method can be applied to several metal oxide supports having different microwave absorption efficiencies,such as MnO2,Al2O3,and TiO2.These catalysts exhibited higher catalytic activities for CO oxidation at low temperature and for selective aerobic oxidation of sulfide than those prepared by conventional methods.
基金supported by the National Natural Science Foundation of China(U1904216).
文摘The uncontrollable Li electrostripping and plating process that results in dendritic Li growth and huge volume change of Li anode limits the practicality of Li metal batteries(LMBs).To simultaneously address these issues,designing three-dimensional(3D),lithiophilic and mechanically robust electrodes seems to be one of the cost-effective strategies.Herein,a new 3D Li-B-C-Al alloy anode is designed and fabricated.The prepared 3D alloy anode exhibits not only superior lithiophilicity that facilitates uniform Li nucleation and growth but also sufficient mechanical stability that maintains its structural integrity.Superior performance of the prepared 3D alloy is demonstrated through comprehensive electrochemical tests.In addition,non-destructive and 3D synchrotron X-ray computed tomography(SX-CT)technique is employed to investigate the underlying working mechanisms of the prepared alloy anode.A unique twofold Li electrostripping and plating mechanism under different electrochemical cycling conditions is revealed.Lastly,improved performance of the full cells built with the 3D alloy anode and LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cathode corroborate its potential application capability.Overall,the current work not only showcases the superiority of the 3D alloy as potential anode material for LMBs but also provides fundamental insights into its underlying working mechanisms that may further propel its research and development.
基金supported by the Natural Science Foundation of China(NSFC grant 41272019,41372021)the "973 project" of the Ministry of Science and Technology of China"(2013CB835002, 2013CB837100)+1 种基金the "111 project" of the Programs of Introducing Talents of Discipline to Universities(No: W20136100061)the MOST Special Fund from the State Key Laboratory of Continental Dynamics,Northwest University,China
文摘The early Cambrian pentamerous microfossil Olivooides/Punctatus in South China, which is characterized by a diagnostic stellate tubular apex, has been well-known for its almost complete development sequence that can be confidently traced from embryos and hatched juveniles, to conical adults. However, its zoological affinity remains highly controversial. Here we describe the internal microanatomic structures of the soft-body inside the peridermal theca of Olivooides multisulcatus Qian, 1977, including interradial pairs of tentacles, adradial and perradial frenula, perradial oral marginal lappets and twins of perradial gastric saccule-like humps as well as a circular velarium with striated coronal muscles. Particularly, one specimen shows bifurcated velarial canals along the bell aperture. Both the components of the soft-body and the external theca （or cyst） are arranged in perfect pentaradial symmetry. These characteristics are more compatible with those of living cubomedusans and co-occurring Cambrian athecate embryonic cubozoans. Concerning the presence of peridermal theca, Olivooides most likely represents an extinct thecate stem-group cubomedusae but devoid of both perradial eyes and specialized pedalia. The well-grown soft body inside the peridermal tube displays a set of mixed features of both polyp and medusa.
文摘Lead dissolved in water must be removed in order not to cause diseases, especially from high pH aqueous solution. Various oxides having high specific surface area are often applied to remove lead in water media. To improve removal ability for lead species, it is necessary to understand the adsorbed structure of lead species on oxides. At first, the adsorption behavior of lead from high pH solution in the presence of Ca<sup>2+</sup> and Na+ was compared. Lead and calcium species were adsorbed up to the monolayer, and the adsorption isotherm was analyzed as Langmuir-type adsorption. In the presence of Ca<sup>2+</sup>, the amount of removed lead was reduced. To clarify this influence of Ca<sup>2+</sup>, X-ray absorption spectroscopy was adopted. It was for the first time revealed that lead species at pH > 12 and pH < 10.5 differed, and that lead species adsorbed on various oxides had a similar structure.
基金supported by the National Key R&D Program of China(No.2021YFA1400300)the National Natural Science Foundation of China(Nos.22271309,12304268,12425403,and 12261131499)+4 种基金the Beijing Natural Science Foundation(No.F251005)the Chinese Academy of Sciences(No.XDB33000000)Duo Wang acknowledges financial support from the Science and Technology Development Fund from Macao SAR(No.0062/2023/ITP2)the Macao Polytechnic University(No.RP/FCA-03/2023)The synchrotron X-ray powder diffraction experiments were performed at SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute(Nos.2024A1506 and 2024A1695).
文摘Negative thermal expansion(NTE)is fascinating,as it involves a material’s volume contraction rather than expansion upon heating.Although NTE lattices typically have highly flexible frameworks,the magnitude of NTE is often very small,and they frequently exhibit a narrow temperature range for controllable NTEs.It remains a great challenge to achieve large NTE while maintaining a wide temperature operation range from the currently available materials.Herein,we present a novel PbTiO_(3)(PT)-based perovskite system,(1−x)PbTiO_(3)-xBiYbO_(3),synthesized via a distinctive highpressure and high-temperature technique.Compared with pristine PbTiO_(3)(c/a=1.064),the system exhibited unusual enhanced tetragonalities.Consequently,NTE over an extended temperatureαVαVαV range has been realized in 0.95PbTiO_(3)-0.05BiYbO_(3)(-av=−2.18×10^(−5)K^(−1),300-820 K)and 0.90PbTiO_(3)−0.10BiYbO_(3)(-av=−1.85×10^(−5)K^(−1),300-850 K)compared with that of pristine PbTiO_(3)(-av=−1.99×10^(−5)K^(−1),300-763 K).Our experimental and theoretical studies indicate that the improved tetragonality and expanded NTE temperature range result from larger ionic displacements and an enhanced asymmetric charge distribution,both of which are induced by BiYbO_(3) substitution.The present study presents a new example of an NTE across a broad temperature range,highlighting its potential as an effective thermal expansion compensator.
基金financially supported by the National Natural Science Foundation of China(Nos.22271309,12425403 and 12261131499)the National Key R&D Program of China(No.2021YFA1400300)+2 种基金financial support from the Science and Technology Development Fund from Macao SAR(No.0062/2023/ITP2)Macao Polytechnic University(No.RP/FCA-03/2023)Synchrotron X-ray powder diffraction experiments were conducted at SPring-8,approved by the Japan Synchrotron Radiation Research Institute(Nos.2024A1506,2024A1695 and 2024B1807)
文摘Negative thermal expansion(NTE)is a notable physical property where a material’s volume decreases instead of increasing when heated.The identification of NTE materials is crucial for thermal expansion control engineering.Most NTE materials exhibit NTE only within a narrow temperature range,restricting their applications.Achieving NTE across a broad temperature range remains a significant challenge.This study developed a novel PbTiO_(3)-based system,(1-x)PbTiO_(3–x)BiLuO_(3),incorporating rare-earth elements,using a distinctive high-pressure and high-temperature synthesis technique.We achieved NTE across a broad temperature range by coupling lattice(c/a)with ferroelectric order parameters.The incorporation of BiLuO_(3)resulted in distinctive ferroelectric characteristics,including increased tetragonality,spontaneous polarization,and NTE over a broad temperature range.NTE over an extended temperature range has been achieved in 0.95PbTiO_(3)–0.05BiLuO_(3)(■=−1.7×10^(–5)K^(−1),300–840 K)and 0.90PbTiO_(3)–0.10BiLuO_(3)(■=−1.4×10^(–5)K^(−1),300–860 K),compared to pristine PbTiO_(3)(■=−1.99×10^(–5)K^(−1),300–763 K).The improved tetragonalities and broader NTE temperature range result from the strong hybridization of Pb/Bi–O and Ti/Lu–O atoms,as demonstrated by combined experimental and theoretical analyses,including high-energy synchrotron X-ray diffraction,Raman spectroscopy,and density functional theory calculations.This study introduces a novel example of NTE over a broad temperature range,highlighting its potential as a high-performance thermal expansion compensator.Additionally,it presents an effective method for incorporating rare-earth elements to achieve NTE in PbTiO_(3)-based perovskites across a wide temperature range.
基金Distinguished Young Foundation of Sichuan Province,Grant/Award Number:2020JDJQ0027National Natural Science Foundation of China,Grant/Award Numbers:22108218,20A20145,21878195+2 种基金German Research Foundation,Grant/Award Number:390874152“Young Talent Support Plan”of Xi'an Jiaotong University,Grant/Award Number:HG6J016Qinchuangyuan Innovative Talent Project,Grant/Award Number:QCYRCXM-2022-137。
文摘With exceptional capacity during high-voltage cycling,P3-type Nadeficient layered oxide cathodes have captured substantial attention.Nevertheless,they are plagued by severe capacity degradation over cycling.In this study,tuning and optimizing the phase composition in layered oxides through Li incorporation are proposed to enhance the high-voltage stability.The structural dependence of layered Na_(2/3)LixNi_(0.25)Mn_(0.75)O_(2)þδoxides on the lithium content(0.0≤x≤1.0)offered during synthesis is investigated systematically on an atomic scale.Surprisingly,increasing the Li content triggers the formation of mixed P2/O3-type or P3/P2/O3-type layered phases.As the voltage window is 1.5-4.5 V,P3-type Na2/3Ni_(0.25)Mn_(0.75)O_(2)(NL0.0NMO,R3m)material exhibits a sequence of phase transformations throughout the process of(de)sodiation,that is,O3⇌P3⇌O30⇌O3″.Such complicated phase transitions can be effectively suppressed in the Na2/3Li_(0.7)Ni_(0.25)Mn_(0.75)O_(2.4)(NL_(0.7)NMO)oxide with P2/P3/O3-type mixed phases.Consequently,cathodes made of NL0.7NMO exhibit a substantially enhanced cyclic performance at high voltages compared to that of the P3-type layered NL0.0NMO cathode.Specifically,NL0.7NMO demonstrates an outstanding capacity retention of 98%after 10 cycles at 1 C within 1.5-4.5 V,much higher than that of NL0.0NMO(83%).This work delves into the intricate realm of bolstering the high-voltage durability of layered oxide cathodes,paving the way for advanced sodium-ion battery technologies.
基金The synchrotron radiation measurements were performed at BL20XU at SPring-8,with the approval of the Japan Syn-chrotron Radiation Research Institute(JASRI,proposal numbers 2022B1020,2022A1003,2021B1005,2021B1004,2021A1017,2020A1782).
文摘High-performance all-solid-state lithium-ion batteries require observation,control,and optimization of the electrode structure.X-ray computational tomography(CT)is an effective nondestructive method for observing the electrode structure in three dimensions.However,the limited availability of synchrotron radiation CT,which offers high-resolution imaging with a high signal-to-noise ratio,makes it difficult to conduct experiments and restricts the use of X-ray CT in battery development.Conversely,laboratory CT systems are widely available,but they use X-rays emitted from a metal target,resulting in lower image quality and resolution compared with synchrotron radiation CT.This study explores a method for achieving comparable resolution in laboratory CT images of all-solid-state batteries to that of synchrotron radiation CT.Our method involves using the synchrotron radiation CT images as training data for machine learning super-resolution.The results demonstrate that,by employing an appropriate machine learning algorithm and activation function,along with a sufficiently deep network,the image quality of laboratory CT becomes equivalent to that of synchrotron radiation CT.
