The effectiveness of dual-doping as a method of improving the conductivity of sulfide solid electrolytes(SEs)is not in doubt;however,the atomic-level mechanisms underpinning these enhancements remain elusive.In this s...The effectiveness of dual-doping as a method of improving the conductivity of sulfide solid electrolytes(SEs)is not in doubt;however,the atomic-level mechanisms underpinning these enhancements remain elusive.In this study,we investigate the atomic mechanisms associated with the high ionic conductivity of the Li_(7)P_(3)S_(11)(LPS)SE and its response to Ag/Cl dual dopants.Synthesis and electrochemical characterizations show that the 0.2 M AgCl-doped LPS(Li_(6.8)P_(3)Ag_(0.1)S_(10.9)Cl_(0.1))exhibited an over 80%improvement in ionic conductivity compared with the undoped LPS.The atomic-level structures responsible for the enhanced conductivity were generated by a set of experiment and simulation techniques:synchrotron X-ray diffractometry,Rietveld refinement,density functional theory,and artificial neural network-based molecular dynamics simulations.This thorough characterization highlights the role of dual dopants in altering the structure and ionic conductivity.We found that the PS_(4) and P_(2)S_(7) structural motifs of LPS undergo transformation into various PS_(x) substructures.These changes in the substructures,in conjunction with the paddle-wheel effect,enable rapid Li migration.The dopant atoms serve to enhance the flexibility of PS_(4)–P_(2)S_(7) polyhedral frameworks,consequently enhancing the ionic conductivity.Our study elucidates a clear structure–conductivity relationship for the dual-doped LPS,providing a fundamental guideline for the development of sulfide SEs with superior conductivity.展开更多
The quantitative determination of the mass fractions of precipitates in steels is very difficult using traditional materials characterization techniques. The Rietveld full-pattern fitting algorithm was introduced to s...The quantitative determination of the mass fractions of precipitates in steels is very difficult using traditional materials characterization techniques. The Rietveld full-pattern fitting algorithm was introduced to solve this problem. The precipitated multicomponents’ mass fraction of M3C, MC, M7C3 and M23C6 were evaluated precisely and relatively quickly. It is found evolution of carbides apparently occurs during tempering at high temperatures, and a two-step transformation mechanism is proposed for M7C3 during early tempering treatment. The method is an effective way on the investigation of precipitation kinetics, which may play a promising role in propertities’ enhancement and design of the heat-resistant steels.展开更多
The crystal structure of compound ErNiSb has been refined by the Rietveld wholepatternfitting method from X-ray powder diffraction data.The compound ErNiSb is cubic, space group F43m and the structure parameters and r...The crystal structure of compound ErNiSb has been refined by the Rietveld wholepatternfitting method from X-ray powder diffraction data.The compound ErNiSb is cubic, space group F43m and the structure parameters and reliability factors were refined to be a=6.268 3(1), V=246.29^(3), Z=4, D_(x)=9.377 g/cm^3, R_(B)=3.57%, R_(F)=3.64%, R_(p)=6.63%, R_(WP)=8.80%.展开更多
The effect of the amount of Sn on the formation of fcc phase in Ti-13 Ta-x Sn(x=3,6,9 and 12,at.%)alloys was studied.The alloys were synthesized by mechanical alloying using a planetary mill,jar and balls of stabilize...The effect of the amount of Sn on the formation of fcc phase in Ti-13 Ta-x Sn(x=3,6,9 and 12,at.%)alloys was studied.The alloys were synthesized by mechanical alloying using a planetary mill,jar and balls of stabilized yttrium.Using Rietveld refinement,it was found that the obtained fcc phase has crystallite size smaller than 10 nm and microstrain larger than 10-3.Both conditions are required to form an fcc phase in Ti-based alloys.For all samples,the microstructure of the fcc phase consists of equiaxial crystallites with sizes smaller than 10 nm.The largest presence of fcc phase in the studied Ti alloy was found with 6 at.%Sn,because this alloy exhibits the largest microstrain(1.5×10-2)and crystallite size of 6.5 nm.Experimental data reveal that a solid solution and an amorphous phase were formed during milling.The necessary conditions to promote the formation of solid solution and amorphous phases were determined using thermodynamic calculations.When the amount of Sn increases,the energy required to form an amorphous phase varies from approximately 10 to approximately-5 k J/mol for 3 and 12 at.%Sn,respectively.The thermodynamic calculations are in agreement with XRD patterns analysis and HRTEM results.展开更多
Ferroelectric lead-free BaTi_(1-x)Zr_(x)O_(3)ceramic powder samples with various compositions(x=0,0.04,0.06)have been synthesized by conventional high-temperature solid-state reaction method at 1450℃for 10 h.Influenc...Ferroelectric lead-free BaTi_(1-x)Zr_(x)O_(3)ceramic powder samples with various compositions(x=0,0.04,0.06)have been synthesized by conventional high-temperature solid-state reaction method at 1450℃for 10 h.Influences of Zr doping on the inter-atomic bonding and charge density distributions inside the lattice structure of BaTiO_(3)were analyzed through powder X-ray diffraction(XRD)and maximum entropy method.Lattice parameter and cell volume values are found to be increasing with the incorporation of Zr content.Calculated average grain sizes are found to be in the range of 23-28 nm.Maximum entropy mapping of electron density analysis reveals the reduction in ionic nature along Ba-O bond and the enhancement of covalent nature along Ti-O bond.Energy band gap values were determined from ultraviolet-visible(UV-Vis)spectra.Surface morphology and microstructures of the samples were analyzed from scanning electron microscopy(SEM)micrographs.Particles with irregular sizes were observed in all the prepared ceramics.Stoichiometry of the samples was further confirmed by energydispersive X-ray spectroscopy(EDAX).展开更多
The CeTi 2O 6, which is formed above 1300 ℃ by ceramic method, was obtained at 700 ℃ using sol gel synthesis method. XRD analysis shows that there is 8% deficient of Ce in the structure. The chemical formula is C...The CeTi 2O 6, which is formed above 1300 ℃ by ceramic method, was obtained at 700 ℃ using sol gel synthesis method. XRD analysis shows that there is 8% deficient of Ce in the structure. The chemical formula is Ce 0.92 Ti 2O 5.84 , which has a monoclinic structure with space group of C 2/ m . Its cell parameters are a =0.9811(8) nm, b =0.3726(3) nm, c =0.6831(6) nm, and β =118.84°. After being treated at 1300 ℃ for 3 h, the system keeps stable but the deficient disappears, while the chemical formula change to the normal CeTi 2O 6, and the cell parameters are a =0.9813(3) nm, b =0.3752(4) nm, c =0.6883(5) nm, β =119.05°. The key to synthesis the precursors of CeTi 2O 6 is that Ti 4+ and Ce 3+ ions must reach the atomistic distributing state and prevent the oxidation of Ce 3+ during sol gel process.展开更多
In the present work, a sol-gel method was employed to prepare nanosized SrAl2O4 powders doped with Eu3＋ions. The raw nano- materials were thermally treated at 900 to 1100℃ for 3 h. The XRD analysis demonstrated that...In the present work, a sol-gel method was employed to prepare nanosized SrAl2O4 powders doped with Eu3＋ions. The raw nano- materials were thermally treated at 900 to 1100℃ for 3 h. The XRD analysis demonstrated that the powders were single-phase nanopowders with high crystallite dispersion. Our studies were focused on relating the luminescence properties of the Eu^3＋ dopant to the NC （nanocrystallites） size. This was achieved by varying the calcinations temperature between 900 and 1100 ℃. The average NC size varied accordingly between -36 and -75 nm. We found that size effect manifested mainly in the expansion of the cell volume and broadening of XRD peaks as indicated by Rietveld analysis. Moreover the emission and excitation spectra, although typical for Eu^3＋ ions, demonstrated some degree of variability with calcinations temperature and doping concentration. To explain these differences a detailed analysis of luminescence spectra by the Judd-Ofelt theory was performed.展开更多
The fine structure of hydrogen storage alloy powders MiNi4.3-xCoxMr0.4AI0.3(x=0.75, 0.45, 0.10; Ml: La-rich misch metal) prepared by rapidly solidifying gas atomization was investigated using a Rietveld analysis metho...The fine structure of hydrogen storage alloy powders MiNi4.3-xCoxMr0.4AI0.3(x=0.75, 0.45, 0.10; Ml: La-rich misch metal) prepared by rapidly solidifying gas atomization was investigated using a Rietveld analysis method. Two sets of CaCu5-type crystal constants were observed in the studied alloys and one set was larger than the other. With decreasing powder radius the solidification rate of powder increased, and so did the percentage of a particle part with larger crystal constants. The reason why there were two sets of crystal constants might be the difference of solidification rate between the outside and inside of a particle.展开更多
基金National Research Foundation of Korea,Grant/A ward Numbers:MEST,NRF-2021R1A2C2009596Engineeringand Physical Sciences Research Council,Grant/A ward Numbers:EP/R029431,EP/P020194,EP/T022213+1 种基金Korea government(Ministry of Science and ICT,MSIT),Grant/Award Number:RS-2023-00236572European Research Council,ERC,Grant/Award Numbers:EP/R029431,EP/P020194,EP/T022213。
文摘The effectiveness of dual-doping as a method of improving the conductivity of sulfide solid electrolytes(SEs)is not in doubt;however,the atomic-level mechanisms underpinning these enhancements remain elusive.In this study,we investigate the atomic mechanisms associated with the high ionic conductivity of the Li_(7)P_(3)S_(11)(LPS)SE and its response to Ag/Cl dual dopants.Synthesis and electrochemical characterizations show that the 0.2 M AgCl-doped LPS(Li_(6.8)P_(3)Ag_(0.1)S_(10.9)Cl_(0.1))exhibited an over 80%improvement in ionic conductivity compared with the undoped LPS.The atomic-level structures responsible for the enhanced conductivity were generated by a set of experiment and simulation techniques:synchrotron X-ray diffractometry,Rietveld refinement,density functional theory,and artificial neural network-based molecular dynamics simulations.This thorough characterization highlights the role of dual dopants in altering the structure and ionic conductivity.We found that the PS_(4) and P_(2)S_(7) structural motifs of LPS undergo transformation into various PS_(x) substructures.These changes in the substructures,in conjunction with the paddle-wheel effect,enable rapid Li migration.The dopant atoms serve to enhance the flexibility of PS_(4)–P_(2)S_(7) polyhedral frameworks,consequently enhancing the ionic conductivity.Our study elucidates a clear structure–conductivity relationship for the dual-doped LPS,providing a fundamental guideline for the development of sulfide SEs with superior conductivity.
基金Funded by the New Products Development Research Projects of Shang-hai Baoshan Iron & Steel Research Institute(X08ECEJ160)
文摘The quantitative determination of the mass fractions of precipitates in steels is very difficult using traditional materials characterization techniques. The Rietveld full-pattern fitting algorithm was introduced to solve this problem. The precipitated multicomponents’ mass fraction of M3C, MC, M7C3 and M23C6 were evaluated precisely and relatively quickly. It is found evolution of carbides apparently occurs during tempering at high temperatures, and a two-step transformation mechanism is proposed for M7C3 during early tempering treatment. The method is an effective way on the investigation of precipitation kinetics, which may play a promising role in propertities’ enhancement and design of the heat-resistant steels.
文摘The crystal structure of compound ErNiSb has been refined by the Rietveld wholepatternfitting method from X-ray powder diffraction data.The compound ErNiSb is cubic, space group F43m and the structure parameters and reliability factors were refined to be a=6.268 3(1), V=246.29^(3), Z=4, D_(x)=9.377 g/cm^3, R_(B)=3.57%, R_(F)=3.64%, R_(p)=6.63%, R_(WP)=8.80%.
基金financial support from FONDECYT Project No.1190797FONDEQUIP/EQM Project No.140095。
文摘The effect of the amount of Sn on the formation of fcc phase in Ti-13 Ta-x Sn(x=3,6,9 and 12,at.%)alloys was studied.The alloys were synthesized by mechanical alloying using a planetary mill,jar and balls of stabilized yttrium.Using Rietveld refinement,it was found that the obtained fcc phase has crystallite size smaller than 10 nm and microstrain larger than 10-3.Both conditions are required to form an fcc phase in Ti-based alloys.For all samples,the microstructure of the fcc phase consists of equiaxial crystallites with sizes smaller than 10 nm.The largest presence of fcc phase in the studied Ti alloy was found with 6 at.%Sn,because this alloy exhibits the largest microstrain(1.5×10-2)and crystallite size of 6.5 nm.Experimental data reveal that a solid solution and an amorphous phase were formed during milling.The necessary conditions to promote the formation of solid solution and amorphous phases were determined using thermodynamic calculations.When the amount of Sn increases,the energy required to form an amorphous phase varies from approximately 10 to approximately-5 k J/mol for 3 and 12 at.%Sn,respectively.The thermodynamic calculations are in agreement with XRD patterns analysis and HRTEM results.
文摘Ferroelectric lead-free BaTi_(1-x)Zr_(x)O_(3)ceramic powder samples with various compositions(x=0,0.04,0.06)have been synthesized by conventional high-temperature solid-state reaction method at 1450℃for 10 h.Influences of Zr doping on the inter-atomic bonding and charge density distributions inside the lattice structure of BaTiO_(3)were analyzed through powder X-ray diffraction(XRD)and maximum entropy method.Lattice parameter and cell volume values are found to be increasing with the incorporation of Zr content.Calculated average grain sizes are found to be in the range of 23-28 nm.Maximum entropy mapping of electron density analysis reveals the reduction in ionic nature along Ba-O bond and the enhancement of covalent nature along Ti-O bond.Energy band gap values were determined from ultraviolet-visible(UV-Vis)spectra.Surface morphology and microstructures of the samples were analyzed from scanning electron microscopy(SEM)micrographs.Particles with irregular sizes were observed in all the prepared ceramics.Stoichiometry of the samples was further confirmed by energydispersive X-ray spectroscopy(EDAX).
文摘The CeTi 2O 6, which is formed above 1300 ℃ by ceramic method, was obtained at 700 ℃ using sol gel synthesis method. XRD analysis shows that there is 8% deficient of Ce in the structure. The chemical formula is Ce 0.92 Ti 2O 5.84 , which has a monoclinic structure with space group of C 2/ m . Its cell parameters are a =0.9811(8) nm, b =0.3726(3) nm, c =0.6831(6) nm, and β =118.84°. After being treated at 1300 ℃ for 3 h, the system keeps stable but the deficient disappears, while the chemical formula change to the normal CeTi 2O 6, and the cell parameters are a =0.9813(3) nm, b =0.3752(4) nm, c =0.6883(5) nm, β =119.05°. The key to synthesis the precursors of CeTi 2O 6 is that Ti 4+ and Ce 3+ ions must reach the atomistic distributing state and prevent the oxidation of Ce 3+ during sol gel process.
基金Project supported by the Polish Ministry of Science and Higher Education (NN 204331537)National Science Centre (N N507 372335)
文摘In the present work, a sol-gel method was employed to prepare nanosized SrAl2O4 powders doped with Eu3＋ions. The raw nano- materials were thermally treated at 900 to 1100℃ for 3 h. The XRD analysis demonstrated that the powders were single-phase nanopowders with high crystallite dispersion. Our studies were focused on relating the luminescence properties of the Eu^3＋ dopant to the NC （nanocrystallites） size. This was achieved by varying the calcinations temperature between 900 and 1100 ℃. The average NC size varied accordingly between -36 and -75 nm. We found that size effect manifested mainly in the expansion of the cell volume and broadening of XRD peaks as indicated by Rietveld analysis. Moreover the emission and excitation spectra, although typical for Eu^3＋ ions, demonstrated some degree of variability with calcinations temperature and doping concentration. To explain these differences a detailed analysis of luminescence spectra by the Judd-Ofelt theory was performed.
文摘The fine structure of hydrogen storage alloy powders MiNi4.3-xCoxMr0.4AI0.3(x=0.75, 0.45, 0.10; Ml: La-rich misch metal) prepared by rapidly solidifying gas atomization was investigated using a Rietveld analysis method. Two sets of CaCu5-type crystal constants were observed in the studied alloys and one set was larger than the other. With decreasing powder radius the solidification rate of powder increased, and so did the percentage of a particle part with larger crystal constants. The reason why there were two sets of crystal constants might be the difference of solidification rate between the outside and inside of a particle.
