Multiscale strain alleviation of Ni-rich cathode guided by in situ environmental transmission electron microscopy during the solid-state synthesis

Ni-rich layered oxides are one of the most promising cathode materials for Li-ion batteries due to their high energy density.However,the chemomechanical breakdown and capacity degradation associated with the anisotropic lattice evolution during lithiation/delithiation hinders its practical application.Herein,by utilizing the in situ environmental transmission electron microscopy(ETEM),we provide a real time nanoscale characterization of high temperature solid-state synthesis of LiNi_(0.8)CO_(0.1)Mn_(0.1)O_(2)(NCM811) cathode,and unprecedentedly reveal the strain/stress formation and morphological evolution mechanism of primary/second ary particles,as well as their influence on electrochemical performance.We show that stress inhomogeneity during solid-state synthesis will lead to both primary/secondary particle pulverization and new grain boundary initiation,which are detrimental to cathode cycling stability and rate performance.Aiming to alleviate this multiscale strain during solid-state synthesis,we introduced a calcination scheme that effectively relieves the stress during the synthesis,thus mitigating the primary/secondary particle crack and the detrimental grain boundaries formation,which in turn improves the cathode structural integrity and Li-ion transport kinetics for long-life and high-rate electrochemical performance.This work remarkably advances the fundamental understanding on mechanochemical properties of transition metal oxide cathode with solid-state synthesis and provides a unified guide for optimization the Ni-rich oxide cathode.

In situ electrochemical synthesis of MOF-5 and its application in improving photocatalytic activity of BiOBr

Metal-organic frameworks（MOFs） are important functional materials. MOF-5（IL）（Zn4O（BDC）3（BDC=1,4-benzenedicarboxylate） was in situ synthesized by the electrochemical method using a tunable ionic liquid（IL）, 1-butyl-3-methylimidazolium chloride, as template. The crystallization of distinctly spherical MOF-5（IL） synthsized in ionic liquid by the electrochemical method is attributed to π-π stacking effect, ionic bond, and coordination bond. The analysis results show that the product MOF-5（IL） exhibits better crystallinity and higher thermal stability than MOF-5 generated using the solvothermal method. The cyclic voltammetry reveals that the electrosynthesis reaction is irreversible and controlled by the diffusion. The experiments on methylorange degradation show that the unique structure characteristics of MOF-5（IL） can enhance the photocatalytic ability of Bi OBr. Therefore, MOFs can replace noble metals to improve the photocatalytic properties of bismuth oxyhalide.

In situ Synthesis of SAPO-34 Zeolites in Kaolin Microspheres for a Fluidized Methanol or Dimethyl Ether to Olefins Process

SAPO-34 zeolite is considered to be an effective catalyst for methanol or dimethyl ether conversion to olefins. In this study,we developed the in situ synthesis technology to prepare SAPO-34 zeolite in kaolin micro-spheres as a catalyst for fluidized methanol or dimethyl ether to olefins process. The silicoaluminophosphate zeolite was first time reported to be synthesized in kaolin microspheres. The SAPO-34 content of synthesized catalyst was about 22% as measured by three different quantitative methods(micropore area,X-ray fluorescence and energy dispersive spectroscopy element analysis) . Most of the SAPO-34 zeolites were in nanoscale size and distributed uniformly inside the spheres. The catalytic performance was evaluated in fixed bed and fluidized bed reactors. Compared with the conventional spray-dry catalyst,SAPO/kaolin catalyst showed superior catalytic activities,bet-ter olefin selectivities(up to 94%,exclusive coke) ,and very good hydrothermal stability. The in situ synthesis of SAPO-34 in kaolin microspheres is a facile and economically feasible way to prepare more effective catalyst for fluidized MTO/DTO(methanol to olefins/dimethyl ether to olefins) process.

Formation of ZrB2in MgO-C Composite Materials Using In-Situ Synthesis Method

ZrB2 in MgO-C composite materials obtained by both microwave sintering synthesis and in-situ reaction at lower temperature was investigated. The test result shows that 66.67 % of reactant changed into Zrb2, and the other form Al2O3, which could optimize the properties of carbon containing materials. Therefore, the method of in situ synthesizing ZrB2 acting as antioxidant in carbon containing materials is considered as one of best ways to reduce the cost and ZrB2 as refractories is used on a large-scale.

Hydrothermal in situ Ligand Synthesis from 1,10-Phenanthroline-5,6-dione and Characterization of 1D Coordination Polymers [Co(bpdc)(H_2O)_3]·H_2O and [Cu(bpy)V_2O_6]

Hydrothermal treatment of MCl2 （ M = Co or Cu ） , NH4 VO3, and 1,10-phenanthroline-5,6-dione （pdon） resulted in the formation of a duplex coordination polymer [ Co （ bpdc ） （ H2O ） 3 ] · H2O （ bpdc = 2,2＇-bipyridine-3,3＇-dicarboxylate） and a chain-like coordination polymer [ Cu （bpy） V2O6 ] （ bpy = 2,2＇-bipyridine ）. X-ray single-crystal structural analysis shows that under hydrothermal conditions and in the presence of different transition metals, the organic reagent pdon was transformed in situ into bpdc and bpy, respectively. Mechanism of the in situ ligand synthesis reaction has been discussed.

A Novel 3D Zn-La Heterometallic Coordination Polymer Involving in situ Glycinate Ligand Synthesis

One novel 3D 3d-4f coordination polymer, [LaZn（glc）（ox）2（H20）2]n （1, glc = glycinate, ox = oxalate）, was obtained by the in situ synthesis of glycinate from the reaction of tetrazole-l-acetic acid, sodium oxalate, zinc nitrate and lanthanide oxide in the presence of a trace quantity of nitric acid under hydrothermal conditions. Compound 1 is of monoclinic, space group P21/n with a = 0.99601（9）, b = 1.14592（10）, c = 1.19107（10） nm and β = 108.7150（10）°. 1 exhibits an unusual 3D heterometallic coordination framework constructed by heterometallic dinuclear LaZn subunits and mixed ox and glc linkers with a uninodal 6-connected vine {33.43.58.6} net.

In Situ Synthesis of Cuprous Oxide/Cellulose Nanofibers Gel and Antibacterial Properties

Cellulose nanofibers were synthesized by acetobacter xylinum(xylinum 1.1812).The cellulose nanofibers with 30-90 nm width constructed three-dimension network gel,which could be used as a wound dressing since it can provide moist environment to a wound.However,cellulose nanofibers have no antimicrobial activity to prevent wound infection.To achieve antimicrobial activity,the cellulose nanofibers can load cuprous oxide(Cu2O)particles on the surface.The cuprous oxide is a kind of safe antibacterial material.The copper ions can be reduced into cuprous oxides by reducing agents such as glucose,N2H4 and sodium hypophosphite.The cellulose nanofibers network gel was soaked in CuSO4 solution and filled with copper ions.The cuprous oxide nanoparticles were in situ synthesized by glucose and embedded in cellulose nanofibers network.The morphologies and structure of the composite gel were analyzed by FESEM,FTIR,WAXRD and inductively coupled plasma(ICP).The sizes of Cu2O embedded in cellulose nanofibers network are 200-500 nm wide.The peak at 605 cm−1 attributed to Cu(I)-O vibration of Cu2O shits to 611 cm−1 in the Cu2O/cellulose composite.The Cu2O/cellulose nanofibers composite reveals the obvious characteristic XRD pattern of Cu2O and the results of ICP show that the content of Cu2O in the composite is 13.1%.The antibacterial tests prove that the Cu2O/cellulose nanofibers composite has the high antibacterial activities which is higher against S.aureus than against E.coli.

In Situ Hydrothermal Synthesis of a Mononuclear Copper(Ⅱ) Complex: Cu(H_2SIP-O)(bpy)(H_2O) (H_4SIP-O=4-Hydroxyl-5-sulfoisophthalic Acid)

The mononuclear complex, Cu（H2SIP-O）（bpy）（H2O） （H4SIP-O = 4-hydroxyl- 5-sulfoisophthalic acid and bpy = 2,2＇-dipyridyl）, has been synthesized by the hydrothermal reaction of Cu（OH）2 with NaH2SIP and bpy at 160 ℃, and characterized by single-crystal X-ray diffraction, elemental analysis and IR spectrum. The new ligand 4-hydroxyl-5-sulfoisophthalic acid derived from 5-sulfoisophthalic acid ligand under an in situ hydrothermal condition. The crystal of the complex crystallizes in a triclinic system, space group P1, with a = 7.757（4）, b = 10.663（6）, c = 11.727（7）A, α = 94.272（4）, β = 104.067（7）, γ = 97.400（7）°, V= 927.4（9）A^3, Z = 2, C18H14N2O9SCu, Mr= 497.93, Dc= 1.783 g/cm^3,μ = 1.350 mm^-1, F（000） = 506, the final R = 0.0518 and wR = 0.1513 for 4180 observed reflections with I 〉 2σ（I）. The central Cu（II） ion is five-coordinated by two oxygen atoms from the H2SIP-O^2- ligand and two nitrogen atoms of bpy ligand in a distorted square-planar geometry as well as a water oxygen atom in the apical position to complete a distorted square-pyramidal coordination geometry. The mononuclear copper molecules are linked by hydrogen bonds between coordinated water molecules and sulfonate groups to form a one-dimensional double-chain structure. The chains are further held together through extensive π-π stacking interactions between the aromatic rings to form a three- dimensional supramolecular structure.

In-Situ Synthesis of Terbium Complex with Salicylic Acid in Silica Matrix by a Two-Step Sol-Gel Process

A process for in situ synthesis of terbium complex with salicylic acid by a two-step solgel method in silica matrix has been proposed. The luminescence properties of the silica gelscodoped with terbium and salicylic acid have also been discussed with respect to that of the geldoped with terbium and that of pure terbium complex with salicylic acid.

In-situ Synthesis of ZSM-5 with Different Si/AlRatios on Honeycomb-shaped Cordierite and their Behavior on NO Decomposition

Zeolites ZSM-5 with different Si/Al ratios were in-situ synthesized on the surface ofhoneycomb-shaped cordierite support for the first time. Characterizations of XRD and SEM wereperformed and it has been proved that the zeolite ZSM-5 was grown on the surface of the cordieritehomogeneously. NO decomposition on the Cu exchanged ZSM-5/cordierite monolith catalysts wasalso studied. It was found that the monolith catalysts have a fine initial activity at 673K and GHSVof 10,000h-1. Such method should be a good way to make auto exhaust converter with monolithcatalyst for NOx removal.

Study on the In-situ Synthesis of Aluminum Titanate Sintered by Waste Aluminum Slag

Aluminum titanate was in-situ synthesized by using industrial waste-residue in the aluminum factory and TiO2 as the main raw materials and the influence of different reaction temperatures on the purity and microstructures of synthesized products were mainly discussed. The obtained Al2TiO5 was characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and relevant analytical software. The results show that elevating the sintering temperature can increase the content of aluminum titanate; and at 1420 ℃, it reaches the highest in the synthesized ceramic. When the sintering temperature continues to increase, the produced aluminum titanate will decompose resulting in the drop of its content. Therefore, the optimum sintering temperature of in-situ synthesis of aluminum titanate is determined as 1420 ℃, at which the grains of aluminum titanate grow completely, the purity of aluminum titanate is 89.3wt%., the highest density is 2.75 g/cm^3, and the porosity is 9%.

Application of Ceramic Coat Synthesized by In-Situ Combustion Synthesis to BF Tuyere

A novel technology of tuyere protection is introduced. The ceramic coat .is synthesized by using in-situ combustion process as the internal, external, and nose protecting coat of BF tuyeres. It can effectively protect the tuyeres and reduce heat loss by cooling water. The technglogy is quick-acting, easy to use, energy-saving and can make tuyeres have long service life. The feasibility of the application of the tuyere ceramic coat is discussed and the energy-saving effect of the tuyere is compared with that of the tuyeres lined with refractory.

In Situ Synthesis of NaY Zeolite with Coal-Based Kaolin

NaY zeolites were in-situ synthesized from coal-based kaolin via thehydrothermal method. The effects of various factors on the structure of the samples were extensivelyinvestigated. The samples were characterized by N_2 adsorption, XRD, IR and DTG-DTA methods, andthe results show that the crystallization temperature and amount of added water play an importantrole in the formation of the zeolite structure. The 4A and P zeolites are the competitive phasepresent in the resulting product. However, NaY zeolites with a higher relative crystallinity,excluding impure crystals and the well hydrothermal stability, can be synthesized from coal-basedkaolin. These zeolites possess a larger surface area and a narrow pore size distribution, and thismeans that optimization of this process might result in a commercial route to synthesize NaYzeolites from coal-based kaolin.

In situ synthesis of Fe-based alloy clad coatings containing TiB_2–TiN –(h-BN)

Fe-based alloy coatings containing TiB2–TiN –（h-BN） were synthesized in situ on Q235 steel substrates by a plasma cladding process using the powders of Fe901 alloy, Ti, and h-BN as raw materials. The effects of Ti/h-BN mass ratio on interfacial bonds between the coating and substrate along with the microstructures and microhardnesses of the coatings were investigated. The results show that the Ti/h-BN mass ratio is a vital factor in the formation of the coatings. Free h-BN can be introduced into the coatings by adding an excess amount of h-BN into the precursor. Decreases in the Ti/h-BN mass ratio improve the microstructural uniformity and compactness and enhance the interfacial bonds of the coatings. At a Ti/h-BN mass ratio of 10/20, the coating is free of cracks and micropores, and mainly consists of Fe-Cr, Fe3B, TiB2, TiN, Ti2N, TiB, FeN, FeB, Fe2B, and h-BN phases. Its average microhardness in the zone between 0.1–2.8 mm from the coating surface is about Hv0.2 551.5.

Synthesis of Ti_3SiC_2/TiB_2 Composite by In-situ Hot Pressing (HP) Method

Ti3SiC2/TiB2 composite was successfully obtained by hot pressing Ti/TiC/Si/B4C power mixtures.Volume fraction of TiB2 in Ti3SiC2/TiB2 composite can not exceed 10%.Incorporation of excessive TiB2 will affect the reactions process.TiC and Ti5Si3 were two important intermediate phases during the whole reactions.The microstructure characteristics of the Ti3SiC2/TiB2 composites were analyzed using scanning electron microscopy （SEM） and transmission electron microscopy （TEM）.The experimental results show that the grains of Ti3SiC2/TiB2 composite are structured in a layered form,and the formation of TiB2 particles as reinforcements with elongated or equiaxed shape distributes in Ti3SiC2 matrix.

Study of the Performance and Microstructure of CeB_6/B_4C Ceramic Composite via in-situ Synthesis

CeB6/B4C ceramic composite was fabricated by hot-pressed sintering via in-situ synthesis reaction among B4C, CeOand C. The effects of CeB6 content on the performance and microstructure of CeB6/B4C composites were investigated. As the content of CeB6 was 2.42%, the microhardness of CeB6/B4C composite reached the maximum of 40.64 GPa, which was higher than that of monolithic B4C by 52.5%. As the content of CeB6 was 4.89%, the flexibility strength and the fracture toughness of CeB6/B4C composite reached the peak values of 346.7 MPa and 5.95 MPa·m1/2 respectively, which were higher than those of monolithic B4C by 17.96% and 61.7% respectively. The integrated mechanical property of CeB6/B4C ceramic composite with the 4.89% CeB6 content is optimal. It was also found that as in-situ synthesis of CeB6, the crystal grain growth was inhibited, and crystallite arrangement was so compact that the pores gradually reduced. The main fracture mode of CeB6/B4C ceramic composite was intercrystalline rupture, while the transcrystalline rupture was minor.

In-Situ Synthesis and Characteristics of TiC-Fe Cermet Graded Composite Coating on a Steel Substrate

By means of an inherent elevated-temperature of poured liquid steel,a Ti-C-30wt%Fe preform,which was pre-placed in a mould cavity,was directly ignited and a combustion synthesis reaction took place.As a result,a TiC-Fe cermet coating with a thickness of about 10mm was simultaneously synthesized on the solidified steel matrix.The synthesized coating exhibits a feature of graded composite structure,in which both the amount and size of TiC particles decrease gradually with an increasing distance from the furface of the coating.Moreover,by a proper casting technique,the pores formed during the combustion synthesis of the preform could be centrally distributed in 2-3mm in outer layer of the coating.When this outer porous layer was worn off,the rest coating with a thickness of about 8mm possesses a dense structure and a high abrasive wear resistance.

A novel strategy for in situ maskless synthesis of biochips:Self-driving micro-fluid porous type printing (SMPTP)

A novel maskless technique, self-driving micro-fluid porous type printing （SMPTP）, was reported to in situ synthesize oligonucleotide arrays on glass slide, which has the merits of low cost, high quality and simple craft. In SMPTP for fabricating gene- chips, porous fiber tubes with a number of nanometric or micron channels functioned as ＂active letters＂ and were assembled in designed patterns, which are identical to the distribution of monomers in each layer of the array, and four patterns were needed for each layer. By means of capillarity, the synthesis solution was automatically taken into porous tubes assembled in a printing plate and reached the surface. An oligonucleotide array of 160 features with four different 15-mer probes was in situ synthesized using this technique. The four specific oligonucleotide probes, including the matched and the mismatched by the fluorescent target sequence, gave obviously different hybridization fluorescent signals.

Synthesis of PMA/Eu_2O_3 porous-layered nanocomposite by in situ polymerization and its morphology

The PMA/Eu2O3 porous and layered nanocomposite was prepared by in situ polymerization and characterized by means of X-ray diffraction （XRD）, transmission electron microscopy （TEM）, scanning electron microscope （SEM）, and inflared ray （IR）. Microscopic investigation of the nanocomposite was carded out by atomic force microscopy （AFM）. The results showed that the shape of the composite was layered and porous. Eu2O3 was grafted when methyl acrylate （MA） polymerized; thus Eu2O3 particles appeared on both sides of the chains of polymeric methyl acrylate （PMA）.