Comparison of the interface reaction behaviors of CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) solid-state systems based on the diffusion couple method

The formation mechanism of calcium vanadate and manganese vanadate and the difference between calcium and manganese in the reaction with vanadium are basic issues in the calcification roasting and manganese roasting process with vanadium slag.In this work,CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples were prepared and roasted for different time periods to illustrate and compare the diffusion reaction mechanisms.Then,the changes in the diffusion product and diffusion coefficient were investigated and calculated based on scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) analysis.Results show that with the extension of the roasting time,the diffusion reaction gradually proceeds among the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples.The regional boundaries of calcium and vanadium are easily identifiable for the CaO–V_(2)O_(5) diffusion couple.Meanwhile,for the MnO_(2)–V_(2)O_(5) diffusion couple,MnO_(2) gradually decomposes to form Mn_(2)O_(3),and vanadium diffuses into the interior of Mn_(2)O_(3).Only a part of vanadium combines with manganese to form the diffusion production layer.CaV_(2)O_(6) and MnV_(2)O_(6) are the interfacial reaction products of the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples,respectively,whose thicknesses are 39.85 and 32.13μm when roasted for 16 h.After 16 h,both diffusion couples reach the reaction equilibrium due to the limitation of diffusion.The diffusion coefficient of the CaO–V_(2)O_(5) diffusion couple is higher than that of the MnO_(2)–V_(2)O_(5) diffusion couple for the same roasting time,and the diffusion reaction between vanadium and calcium is easier than that between vanadium and manganese.

A review of ^(17)O isotopic labeling techniques for solid-state NMR structural studies of metal oxides in lithium-ion batteries

Recent advances in utilizing ^(17)O isotopic labeling methods for solid-state nuclear magnetic resonance(NMR)investigations of metal oxides for lithium-ion batteries have yielded extensive insights into their structural and dynamic details.Herein,we commence with a brief introduction to recent research on lithium-ion battery oxide materials studied using ^(17)O solid-state NMR spectroscopy.Then we delve into a review of ^(17)O isotopic labeling methods for tagging oxygen sites in both the bulk and surfaces of metal oxides.At last,the unresolved problems and the future research directions for advancing the ^(17)O labeling technique are discussed.

Solid-state mechanochemistry advancing two dimensional materials for lithium-ion storage applications:A mini review

The vigorous development of two-dimensional(2D)materials brings about numerous opportunities for lithiumion batteries(LIBs)due to their unique 2D layered structure,large specific surface area,outstanding mechanical and flexibility properties,etc.Modern technologies for production of 2D materials include but are not limited to mechanochemical(solid-state/liquid-phase)exfoliation,the solvothermal method and chemical vapor deposition.In this review,strategies leading to the production of 2D materials via solid-state mechanochemistry featuring traditional high energy ball-milling and Sichuan University patented pan-milling are highlighted.The mechanism involving exfoliation,edge selective carbon radical generation of the 2D materials is delineated and this is followed by detailed discussion on representative mechanochemical techniques for tailored and improved lithium-ion storage performance.In the light of the advantages of the solid-state mechanochemical method,there is great promise for the commercialization of 2D materials for the next-generation high performance LIBs.

Strontium ferrite powders prepared from oily cold rolling mill sludge by solid-state reaction method

Oily cold rolling mill （CRM） sludge is one of the pollutants emitted by iron and steel plants. Recycling oily CRM sludge can not only reduce pollution but also bring social and environmental benefits. In this study, using oily CRM sludge as sources of iron oxide, the strontium ferrite powders were synthesized in multiple steps including vacuum distillation, magnetic separation, oxidizing roasting, and solidstate reaction. The optimal technological conditions of vacuum distillation and oxidizing roasting were studied carefully. To consider the effects of Fe203/ SrCO3 tool ratio, calcination temperature, milling time and calcination time on magnetic properties of prepared strontium ferrite powders, the orthogonal experimental method was adopted. The maximum saturation magneti- zation （62.6 mA-m2.g-1） of the synthesized strontium ferrite powders was achieved at the Fe203/SrCO3 mol ratio of 6, 5 h milling time, 1250 ~C calcination temperature, and 1 h calcination time. Strontium ferrite powders syn- thesis method not only provides a cheap, high quality raw material for the production of strontium ferrite powders, but also effectively prevents the environmental pollution.

Preparation of Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 powders for cathode material in secondary battery by solid-state method

Employing Li2CO3, NiO, Co3O4, and MnCO3 powders as starting materials, Li[Ni1/3Co1/3Mn1/3]O2 was synthesized by solid-state reaction method. Various grinding aids were applied during milling in order to optimize the synthesis process. After successive heat treatments at 650 and 950 ℃, the prepared powders were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy, and transmission electron microscopy. The powders prepared by adding salt (NaCl) as grinding aid exhibit a clear R3m layer structure. The powders by other grinding aids like heptane show some impurity peaks in the XRD pattern. The former powders show a uniform particle size distribution of less than 1 μm average size while the latter shows a wide distribution ranging from 1 to 10 μm. Energy dispersive X-ray (EDX) analysiss show that the ratio of Ni, Co, and Mn content in the powder is approximately 1/3, 1/3, and 1/3, respecively. The EDX data indicate no incorporation of sodium or chlorine into the powders. Charge-discharge tests gave an initial discharge capacity of 160 mAh·g-1 for the powders with NaCl addition while 70 mAh·g-1 for the powders with heptane.

Thermal kinetic analysis of a complex process from a solid-state reaction by deconvolution procedure from a new calculation method and related thermodynamic functions of Mn_(0.90)Co_(0.05)Mg_(0.05)HPO_4?3H_2O

Three individual peaks of thermal solid-state reaction processes of the synthesized Mn0.90Co0.05Mg0.05HPO4?3H2O were observed corresponding to dehydration I,dehydration II and polycondensation processes.An alternative method for the calculation of the extent of conversion was proposed from the peak area of the individual DTG peak after applying the best fitting deconvolution function(Frazer–Suzuki function).An iterative integral isoconversional equation was used to compute the values of the apparent activation energy Eαand they were found to be 65.87,78.16 and 119.32 kJ/mol for three peaks,respectively.Each individual peak was guaranteed to be a single-step kinetic system with its unique kinetic parameters.The reaction mechanism functions were selected by the comparison between experimental and model plots.The results show that the first,second and final individual peaks were two-dimensional diffusion of spherical symmetry(D2),three-dimensional diffusion of spherical symmetry(D3)and contracting cylinder(cylindrical symmetry,R2)mechanisms.Pre-exponential factor values of 3.91×106,1.35×107 and 2.15×107 s?1 were calculated from the Eαvalues and reaction mechanisms.The corresponded standard thermodynamic functions of the transition-state(activated)complexes were determined and found to agree well with the experimental data.

A Hybrid Backward Euler Control Volume Method to Solve the Concentration-Dependent Solid-State Diffusion Problem in Battery Modeling

Several efficient analytical methods have been developed to solve the solid-state diffusion problem, for constant diffusion coefficient problems. However, these methods cannot be applied for concentration-dependent diffusion coefficient problems and numerical methods are used instead. Herein, grid-based numerical methods derived from the control volume discretization are presented to resolve the characteristic nonlinear system of partial differential equations. A novel hybrid backward Euler control volume (HBECV) method is presented which requires only one iteration to reach an implicit solution. The HBECV results are shown to be stable and accurate for a moderate number of grid points. The computational speed and accuracy of the HBECV, justify its use in battery simulations, in which the solid-state diffusion coefficient is a strong function of the concentration.

Effect of Ball-Milling Time on the Performance of Ni-Al2O3 Catalyst for 1,4-Butynediol Hydrogenation to Produce 1,4-Butenediol

The Ni-Al2O3 catalyst was prepared by the mechanochemical method in combination with a planetary ballmilling machine.Effect of milling time on the crystal structure,the reduction characteristics and the catalytic performance of Ni-Al2O3 catalyst for hydrogenation of 1,4-butynediol to produce 1,4-butenediol were investigated.The catalysts were characterized by PSD,EDX,XRD,H2-TPR,BET,TEM,and NH3-TPD methods.Results showed that the MCt2.5 catalyst treated at a ball milling time of 2.5 h could form a smallest particle size of 191.0 nm.The evaluation experiments revealed that the activity of the prepared catalyst increased at first and then reached a constant value with the extension of ballmilling time.The BYD conversion,BED selectivity and yield on the MCt2.5 catalyst reached 35.63%,33.48%and 32.46%,respectively,which were higher than those obtained by other samples.The excellent performance of MCt2.5 sample is mainly related to the following three reasons from characterization results.Firstly,it has a smallest particle size of 191.0 nm;and then,the surface acidity(in terms of strong acids)of the catalyst was weaker than other catalysts;and eventually,the loading amount(23.84%)of the active component Ni exceeded the theoretical value(20%).

The effect of agglomerate on micro-structural evolution in solid-state sintering

Discrete element method （DEM） is used in the present paper to simulate the microstructural evolution of a planar layer of copper particles during sintering. Formation of agglomerates and the effect of their rearrangement on densification are mainly focused on. Comparing to the existing experimental observations, we find that agglomerate can form spontaneously in sintering and its rearrangement could accelerate the densification of compacts. Snapshots of numerical simulations agree qualitatively well with experimental observations. The method could be readily extended to investigate the effect of agglomerate on sintering in a three- dimensional model, which should be very useful for understanding the evolution of microstructure of sintering systems.

First Principle Material Genome Approach for All Solid-State Batteries

Due to ever-increasing concern about safety issues in using alkali metal ionic batteries, all solid-state batteries (ASSBs) have attracted tremendous attention. The foundation to enable high-performance ASSBs lies in delivering ultra-fast ionic conductors that are compatible with both alkali anodes and high-voltage cathodes. Such a challenging task cannot be fulfilled, without solid understanding covering materials stability and properties, interfacial reactions, structural integrity, and electrochemical windows. Here in this work, we will review recent advances on fundamental modeling in the framework of material genome initiative based on the density functional theory (DFT), focusing on solid alkali batteries. Efforts are made in offering a dependable road chart to formulate competitive materials and construct "better" batteries.

Effect of Dopant Concentration on Luminescence Properties of KCaPO4:Sm

KCaPO4 doped with different concentrations of Sm was synthesised by a high-temperature solid-state method, and the crystal structure, morphology, TL and OSL properties of Sm-doped KCaPO4 were systematically investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermoluminescence (TL), and optically stimulated luminescence (OSL) techniques. The results show that 0.3 mol% Sm-doped KCaPO4 annealed at 1073 K for 1 h has the highest TL intensity, and thus is expected to be a candidate material for thermoluminescence dosimetry applications.

AN ENERGY-STABLE PARAMETRICFINITE ELEMENT METHOD FOR SIMULATING SOLID-STATE DEWETTING PROBLEMS INTHREE DIMENSIONS

We propose an accurate and energy-stable parametric finite element method for solving the sharp-interface continuum model of solid-state dewetting in three-dimensional space.The model describes the motion of the film/vapor interface with contact line migration and is governed by the surface diffusion equation with proper boundary conditions at the contact line.We present a weak formulation for the problem,in which the contact angle condition is weakly enforced.By using piecewise linear elements in space and backward Euler method in time,we then discretize the formulation to obtain a parametric finite element approximation,where the interface and its contact line are evolved simultaneously.The resulting numerical method is shown to be well-posed and unconditionally energystable.Furthermore,the numerical method is generalized to the case of anisotropic surface energies in the Riemannian metric form.Numerical results are reported to show the convergence and efficiency of the proposed numerical method as well as the anisotropic effects on the morphological evolution of thin films in solid-state dewetting.

Preparation of BaCe_(0.5)Zr_(0.4)Y_(0.1)O_(3-α) by Sol-Gel Method and Its Electrical Properties

A precursor of BaCe0.5Zr0.4Y0. 1O3-α electrolytes was synthesized by the sol-gel method and sintered at temperature which were 150 - 250 ℃ lower than by solid state reaction. The AC impedance spectrums of electrolytes were measured by AUTOLAB PGSTA30 electrochemical measuring device at different temperatures. The conductivities of the electrolytes are 1.62×10^-4 - 6.43×10^-3, 2.52×10^-5 - 3.73×10^-3S·cm^-1 in the temperature range of 350-800℃. The activity energies are 0.54 and 0.84 eV. At the same time BaCe0.9Y0.1O3-α was prepared by direct solid state reaction. The conductivity of BaCe0.9Y0.1O3-α is 1 × 10^-4- 4×10^-3 S·cm^-1 and the activation energy is 0.50 eV at the same condition. The results show that conduction of electrolyte prepared by sol-gel method is higher than the one by solid state reaction. As far as BaCe0.9Y0.1O3-α concerned, its conductivity of the Zr-substituted specimens is decreased.

Study of Sm_(0.2)Ce_(0.8)O_(1.9)(SDC) electrolyte prepared by a simple modified solid-state method

Sm0.2Ce0.8O1.9 （SDC） electrolyte was prepared by a modified solid state method at relatively low sintering temperatures without any sintering promoters. The phase composition and microstructure of the electrolytes were investigated by X-ray diffraction （XRD） and field emission scanning electron microscopy （FESEM） technologies. A relative density of SDC electrolyte sintered at 1300 ℃ reached 97.3%and the mean SDC grain size was about 770 nm. Their ionic conductivity and thermal expansion coefficient were also measured by electrochemical workstation and dilatometer. The electrolyte attained a high conductivity of 5×10^-2 S/cm at 800 ℃ with an activation energy of 1.03 eV and a proper thermal expansion coefficient of 12.6×10^-6 K^-1.

Research on charge ordering and magnetic properties in La_(0.3)Ca_(0.7)Mn_(1-x)W_xO_3 system

The perovskite manganite sample La0.3Ca0.7Mn1-xWxO3 （x = 0.08, 0.12） was prepared by the solid-state reaction method. The effect of W doping on the Mn site to La0.3Ca0.7MnO3 charge ordering phase and the changing process of magnetic properties were studied through the measurement of the M-T curve, M-H curves, and ESR curves of the sample. The results showed that when x = 0.08, the charge ordering （CO） phase exists in the system, the transition temperature Tco= 275 K, and the system exhibits PM when T 〉 275 K. The system transforms from spin-disordering paramagnetism to spin-ordering antiferromagnetism in the charge ordering state with the temperature decreasing from 275 K to 230 K. The long-range antiferromagnetism forms and AFM/CO states coexist between 230 K and 5 K. There is a little ferromagnetic component in the AFM/CO background in a low temperature range. When x = 0.12, the CO phase in the system has almost melted completely. There is a little remnant of the CO phase below 150 K. The system exhibits paramagnetism when T 〉 150 K and transforms from paramagnetism to ferromagnetism when T〈 150 K.

Preparation and Characterization of W-Type Hexaferrite Doped with La^(3+)

A series of W-type ferrites with the composition ofBal-xLaxCo2Fe16O27（where, x =0.0, 0.05, 0.10, 0.15, 0.20 and 0.25） were prepared by solid-state reaction method. The structure transformations of the ferrites were examined by XRD, DTA-TG and XPS, and the microwave-absorbing properties were investigated by evaluating the permeability and permittivity of materials（μτ,ετ, ）. The results showed that the phase-transition temperature increased with the addition of La^3＋ content, and a single-phase was formed at 1250℃ at last. Microwave properties were obviously improved as a result of the substitution of La^3＋ for Ba^2＋ at the frequency range of 0.5 - 18.0 GHz.

AB_5-type Hydrogen Storage Alloy Modified with Ti/Zr Used as Anodic Materials in Borohydride Fuel Cell

Fuel cell using borohydride as the fuel has received much attention. AB5-type hydrogen storage alloy used as the anodic material instead of noble metals has been investigated. In order to restrain the generation of hydrogen and enhance the utilization of borohydride, Ti/Zr metal powders has been added into the parent LmNi4.78Mn0.22 （where Lm is La-richened mischmetal） alloy （LNM） by ball milling and heat treatment methods. It is found that the addition of Ti/Zr metal powders lowers the electrochemical catalytic activity of the electrodes, at the same time, restrains the generation of hydrogen and enhances the utilization of the fuel. All the results show that the hydrogen generation rate or the utilization of the fuel is directly relative to the electrochemical catalytic activity or the discharge capability of the electrodes. The utilization of the fuel increases with discharge current density. It is very important to find a balance between the discharge capability and the utilization of the fuel.

A Novel Synthesis of Polyaniline Doped with Heteropolyacid and its Special Property

Polyaniline doped with heteropolyacid was synthesized using solid-state synthesis method. XRD pattern showed that polyaniline molecule has highly ordered arrangement. Fluorescence property of the polyaniline materials was found.

Synthesis and characterization of Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-σ)

Perovskite-type Ba0.5Sr0.5Co0.8Fe0.2O3-σ （BSCFO） powders were synthesized using two methods, solid-state reaction （SSR） method and citrate-EDTA complexing method （CC-EDTA）. Then the powders were pressed to green disks of 19 nun in diameter and sintered at 1140℃ for 5 h. The shrinkage rate and relative density of the membranes prepared from the perovskite-type powders were determined and calculated, and the powders and derived membranes were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The resuits show that the shrinkage rates of the two kinds of disks are nearly the same （about 10%）. The disks prepared by the SSR method had a bigger grain size and lower relative density than those prepared by the CC-EDTA method. The conductivity of the membranes prepared by the SSR method was about 38 S/cm, higher than that of the membranes prepared by the CC-EDTA method, which was about 30 S/cm, at the same temperature of600℃.

Growth and Spectral Properties of Yb^(3+)-doped Ba_3Gd(BO_3)_3 Crystal

Crystal of Yb^3＋-doped Ba3Gd（BO3）3 has been grown by the Czochralski method. The spectroscopic characterizations have been investigated at room temperature. The Yb^3＋：Ba3Gd（BO3）3 crystal exhibits broad absorption at 976 nm with FWHM of 7 nm and large overall spitting of ^2F7/2 manifold （823 cm^-1）. The absorption and emission cross sections are 5.09×10^-21 cm^2 at 976 nm and 0.97×10^-21 cm^2 at 1040 nm, respectively. The fluorescence lifetime is 2.84 ms.