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Because aluminum-based parts cannot be used for long-term applications in large load-wear environments, nickel–tungsten (molybdenum disulfide)/carbon fiber/aluminum composites were successfully prepared in this study for that purpose. By adjusting the plating solution ratio, nickel–tungsten was used as a carrier to introduce molybdenum disulfide nanoparticles, forming a nickel–tungsten/molybdenum disulfide composite coating on the surface of carbon fibers. To enhance the interfacial bonding strength between the carbon fiber and aluminum matrix, a laser was employed to induce the formation of a honeycomb-like structure on the surface of the aluminum base. This increased the contact area between the carbon fiber, aluminum matrix, and epoxy resin adhesives, forming a nickel–tungsten (molybdenum disulfide)/carbon fiber/aluminum composite material. The performance of this composite material was tested and analyzed. The results demonstrated that compared with the carbon fiber/aluminum composite material, the shear strength of the nickel–tungsten (molybdenum disulfide)/carbon fiber/aluminum composite material was increased by 129.7 %, and the friction coefficient and wear rate were reduced by 54.8 % and 83 %, respectively. Next, investigation of the mechanism underlying the honeycomb structure's contribution to the adhesive strength of the composites and their resistance to shear load revealed that the wear-resistant mechanism of molybdenum disulfide nanoparticles reinforced the nickel–tungsten composite coatings. The preparation and study of nickel–tungsten (molybdenum disulfide)/carbon fiber/aluminum composites provide a reference for expanding the applications of aluminum-based composite materials to meet the service requirements of complex environments. [ABSTRACT FROM AUTHOR]

To obtain γ-Al 2 O 3 ultrafiltration membranes, AlOOH sols which were usually derived from aluminum alkoxide were used as the top layer precursor. However, the colloidal sols obtained by this process were complex, high cost and time-consuming. Pseudo-boehmite, an industrial product with characteristics of high purity, excellent gelation and strong caking property, was widely used to prepare γ-Al 2 O 3 products. In this work, mesoporous γ-Al 2 O 3 ultrafiltration membranes were prepared conveniently and quickly by using pseudo-boehmite powder as precursor with colloidal sol-gel route at room temperature. The effects of H+/Al3+ molar ratio and polyvinyl alcohol (PVA) content on the properties of AlOOH sols and γ-Al 2 O 3 ultrafiltration membranes were analyzed. Results showed that the viscosity and hydrodynamic particle diameter of the AlOOH sols can be controlled by changing the H+/Al3+ molar ratio, and the pore size of the prepared γ-Al 2 O 3 ultrafiltration membranes could be varied by adjusting the PVA content in the AlOOH sols coating slurry. The pore size increased from 6.98 nm to 11.34 nm by increasing PVA content from 1.25% to 1.50%. Additionally, the γ-Al 2 O 3 ultrafiltration membranes derived from the pseudo-boehmite exhibited a relatively high permeability (＞94.5 L m−2 h−1⋅MPa−1), which was higher than that of the aluminum alkoxide derived. [ABSTRACT FROM AUTHOR]

This study presents an analysis of the characterization and crystal structure of a series of materials, namely ZrW 2- x Mo x O 8 (0 ≦ x ≦ 1). The isotropic coefficient of thermal expansion of these materials exhibited a systematic and progressive approach from negative values to zero thermal expansion, which is dependent on the increasing value of x. The range of the linear coefficient of thermal expansion, α l , for the entire series was observed to be between −8.44 × 10−6/°C and approximately −4.0 × 10−6/°C. In-situ X-ray diffraction and In-situ Raman spectroscopy were used to study the different structures of ZrW 2- x Mo x O 8 (0 ≦ x ≦ 1), elucidating the changing rule of the thermal expansion coefficient and the mechanism of the ordered-disordered phase transition. According to Rietveld refinement results, Mo doping causes a decrease in the lattice parameters of the entire system and slows down the transverse motion of the bridge oxygen atoms in the small cell volume, which reduces the negative thermal expansion. As the interaction between W (Mo) and a single coordination oxygen atom weakened, the phase transition temperature decreased. This is because the W(Mo)1O 4 and W(Mo)2O 4 polyhedron can be flipped more easily via the "ratchet" process due to the lower electronegativity of the Mo atom (2.16 Pauling) compared to that of the W atom (2.36 Pauling). Furthermore, the impact of Mo substitution for W sites on the electronic structure was initially reported through X-ray photoelectron spectroscopy. [ABSTRACT FROM AUTHOR]

FeSiCr soft magnetic composites (SMCs) with yttrium iron garnet (YIG) coating layer were studied in this work. The YIG with nano size was synthesized by reverse co-precipitation method, which was coated on FeSiCr powders with different YIG contents. The effect of the annealing temperature on the FeSiCr/YIG SMCs was also investigated. It was found that a moderate amount of YIG ferrite could form a thin and uniform layer, resulting in significant optimizations in core loss, permeability, and DC bias characteristics. The results show that the FeSiCr/YIG SMCs with 0.75 wt% YIG exhibit the best magnetic performance (P cv = 131.34 mW/cm3, μ e = 44.5 at 10 mT and 500 kHz). In addition, it was demonstrated that the FeSiCr/YIG SMCs with 0.75 wt% YIG presented the lowest core loss and largest permeability at the optimal annealing temperature of 500 °C. This study provides a new kind of FeSiCr/YIG SMCs which have good prospects to be used in high-frequency fields. [ABSTRACT FROM AUTHOR]

In this work, expanded graphite (EG) was dispersed inside modified polysiloxane resin and successfully printed various cellular structures with span feature via ultraviolet-thermal field co-assisted direct ink writing. The carbon-rich layer was in-situ deposited in the designed porous structure surface by no gas flow pyrolysis process. The characterization of Raman and X-ray photoelectron spectroscopy indicate that the deposited cladding structure possessed amounts of sp2-C, and mainly bonds to the matrix in the manner of Si–C. The presence of cladding structure played a vital role in enhancing the electric conductivity and interface polarization, resulting in excellent microwave absorption performance. The addition of expanded graphite also improved the dielectric property by reinforcing the internal interfacial polarization and achieving a good impedance matching. Finally, the structure reached a minimum reflection loss of −59.31 dB at the thickness of 2.8 mm, and a broadband absorption of 4.2 GHz in the X-band (8.2–12.4 GHz) at 3.1 mm, covering the whole X band. The novelty strategy of controlling the surface state by pyrolysis vapor self-deposition can open a new avenue to tailor the functional characteristic of materials, especially on the assist of direct ink writing which can easy realize complex structural geometry on-demand. [ABSTRACT FROM AUTHOR]

With the rapid development of microelectronics and portable devices, flexible piezoelectric electricity generators (FPEGs) as self-powered devices have attracted extensive attention. Piezoelectric ceramic-polymer composites with good flexibility is the core component of FPEGs. Having high d 33 and g 33 values is also essential for power generation. Herein, the porous ceramic skeleton is prepared using PZT based as the ceramic powder and polyurethane sponge as the template, followed by compounding the porous ceramic skeleton with polydimethylsiloxane (PDMS) by vacuum impregnation to prepare a 3-3 interconnected composite. When the ratio of ceramic phase in the ceramic slurry is 75 wt%, the volume fraction of the ceramic phase in the composite can achieve 37 vol%. Before compounding PDMS, porous ceramics are polarised, which is called pre-polarisation. The d 33 value of the pre-polarised composites can reach 158 pC/N as compared to not polarising the porous ceramic and then polarising it after composite; the improvement is 48%. In addition, the g 33 value of the pre-polarized composites is up to 144 mV m/N. Moreover, the 3.0 × 1.2 × 0.2 cm3 FPEG can generate a maximum output voltage of 15 V and a maximum short circuit current of 167 nA at 9% compression strain. The maximum instantaneous power density is 990 nW/cm2, thereby providing a new idea for piezoelectric power generation. [ABSTRACT FROM AUTHOR]

Fe/C core-shell nanofibers were prepared via a coaxial electrospinning technique integrated with high-temperature carbonization, in which the Fe(NO 3) 3 -containing PAN solution and Fe(NO 3) 3 constituted the shell and core structures, respectively. The core-shell structure was perfectly maintained after carbonization, and Fe nanoparticles were uniformly distributed within the carbon nanofibers. The effects of the microscopic morphology and crystallinity of the carbon components on the electromagnetic properties, matching characteristics, and electromagnetic wave absorption properties of the Fe/C nanofibers were investigated by adjusting the carbonization temperature. As-prepared Fe/C-800 °C core-shell nanofibers mixed with 10 wt% of paraffin showed a minimal reflection loss (RL min) of −20.6 dB under 11.52 GHz at 2.5 mm of thickness and lower than −20 dB under 2.3–5.0 mm of thickness. The efficient absorption bandwidth (EAB) was 6.24 GHz in the range of 11.76–18 GHz at 2.1 mm, covering the whole Ku band. The absorption bandwidth can cover the whole X and Ku bands by varying the sample thickness. The efficient absorption bandwidth was 3.84 GHz in the range of 8.08–11.92 GHz at 2.9 mm, covering the X band. The effective complementarities between the magnetic loss of Fe nanoparticles, the dielectric loss of PAN-based carbon, and the core-shell structure promoted impedance matching and multiple interface polarization, endowing the produced composites with prominent absorption characteristics of microwaves. Therefore, the prepared Fe/C core-shell nanofibers are an ideal lightweight and broadband electromagnetic wave (EMW)-absorbing material that exhibits high-performance microwave absorption. [ABSTRACT FROM AUTHOR]

Core-shell ceramics fibers with multiple composition are ideal candidates for thermal insulation application at high temperature. Herein, ultrathin C–SiC/ZrSi x O y C z core-shell fibers were successfully fabricated by coaxial electrospinning and high temperature pyrolysis with polycarbosilane (PCS) as core precursor and Zirconium butoxide as shell precursor, respectively. The ceramics fibers revealed distinct core-shell partition. The average diameter was about 3 μm and the shell thickness increased to 500 nm with increasing pyrolysis temperature. Thermogravimetry analysis (TGA) results showed that the weight of the fibers reduced to 60% in Ar atmosphere and rose to 108% in O 2 atmosphere, which confirmed the excellent thermal stability and anti-oxidation properties due to the protection effect of shell layer and the self-healing mechanism. Moreover, the ceramics fibers maintained good flexibility and deformability. Such optimized anti-oxidation and mechanical performance indicates that the prepared core-shell fibers could be an excellent thermal insulation material for high temperature application. [ABSTRACT FROM AUTHOR]

In order to enhance the slag resistance of Al 2 O 3 -spinel castables, (Al,Cr) 2 O 3 is added into Al 2 O 3 -spinel system as a pre-synthesized micro-powder. Firstly, (Al,Cr) 2 O 3 micro-powder is synthesized by sintering under reduction conditions to prevent the formation of hexavalent chromium. The Al 2 O 3 -spinel castables are prepared using tabular alumina, fused spinel, α-Al 2 O 3 micro-powder, calcium aluminate cement and (Al,Cr) 2 O 3 micro-powder as the raw materials. The bulk density, porosity, mechanical properties, and slag resistance of the samples are tested. Afterward, the effects of (Al,Cr) 2 O 3 micro-powder (0–3 wt%) on the slag resistance and microstructures of the Al 2 O 3 -spinel castables are assessed by X-ray diffraction (XRD) and energy-dispersive (SEM-EDS) analysis. The results show that the addition of (Al,Cr) 2 O 3 micro-powder can could inhibit the deteriorating effects of Cr3+ on the mechanical properties of the samples. The microstructure results also shows that with the addition of the (Al,Cr) 2 O 3 micro-powder, a secondary solid solution of Ca(Al,Cr) 12 O 19 formed, causing the unit cell to become larger. In the slag erosion area, CA 6 crystals formed with network-like interwoven structures, high density, and greater thickness. These characteristics significantly reduce the erosion and permeability indices of the castables, and improve the slag erosion resistance of the material. [ABSTRACT FROM AUTHOR]

As a lead-free material, AgNbO 3 has received a lot of attention for its potential application in the field of energy storage. Herein, Ag x NbO 2.5+ x /2 ceramics were successfully synthesized via solid state reaction with the x ranged from 1 to 0.92. The effect of silver deficiency on structure, dielectric properties and energy storage performance was investigated. As x value decreased from 1 to 0.94, the unit volume of Ag x NbO 2.5+ x /2 ceramics contracted. Meanwhile, all the compositions displayed double hysteresis loops with reduced P max , P r and enhanced transformation fields (E F and E B) as functions of silver deficiency. Silver deficiency stabilized the antiferroelectric state in the FIE (-like) phase and improved the energy storage performance of AgNbO 3 ceramics. Hence, an enhanced energy storage performance (W rec = 3.1 J/cm3, η = 49%) were achieved in Ag 0.94 NbO 2.97 ceramic. [ABSTRACT FROM AUTHOR]

In this study, dicobalt tetrasulfide (NiCo 2 S 4) nanoneedles were successfully synthesized by a two-step hydrothermal method on nickel foam. A layer of polypyrrole (PPy) was further wrapped on the surface of the NiCo 2 S 4 nanoneedles by in-situ polymerization. The obtained NiCo 2 S 4 @PPy composite was investigated for supercapacitor applications, which exhibited a capacitance of 1842.8 F g−1 at 1 A g−1. An asymmetric supercapacitor device fabricated with an activated carbon negative electrode and NiCo 2 S 4 @PPy positive electrodes exhibited an energy density of 41.2 Wh kg−1 at 402.2 W kg−1 with a high charge–discharge cycling stability (92.8% after 5000 cycles). These results demonstrate that NiCo 2 S 4 @PPy electrodes have broad application prospects as energy storage electrode materials. [ABSTRACT FROM AUTHOR]

A laser etching method was performed to achieve the dual purpose of fabricating grating structures and laser annealing on aluminum-doped zinc oxide (AZO) thin films, and thus improve the film photoelectric performances. Different line spacings and laser fluences were adopted to systematically explore the optimal laser etching condition. Too narrow line spacings or too high laser fluences led to light reflections at the grating external surface to cause more light dissipation, and too wide line spacings or too low laser fluences resulted in relatively small total grating lateral areas being detrimental to multiple internal light reflections. Moreover, too narrow line spacings brought about laser-caused lattice disorder and too high laser fluences produced laser-ablated spots or overburned traces. Therefore, using the medium line spacing and laser fluence, e.g. 40 μm and 0.6 J/cm2 in the present work, was more suitable for synchronously realizing grating structure fabrication and laser annealing. The corresponding AZO film exhibited the maximum figure of merit of 2.89 × 10−2 Ω−1, which was 1.6 times that of the untreated AZO film. This study is expected to expand performance improvement methods of TCO films and promote the application of laser-etched grating structures. [ABSTRACT FROM AUTHOR]

Li–S battery is considered as one of the most competitive energy storage devices mainly due to the high theoretical specific capacity and high specific energy. However, when facing with the practical application, some issues, especially poor electro-conductivity of element sulfur and severe polysulfides (LiPSs) migration, are still needed to solve to further improve the performance of the Li–S batteries. Aiming at the above two disadvantages, in this work, multifunctional separators are designed as efficient LiPSs absorber via coating vapor grown carbon fiber/MoS 2 (VGCF/MoS 2) composites on the polypropylene separator (PP) near the cathode side. For the as-prepared VGCF/MoS 2 coated polypropylene separator (VM/PP), MoS 2 could provide strong chemical adsorption for the LiPSs, while the VGCF framework could act as an electronic transmission channel for the conversion of LiPSs, and also provide physical adsorption for LiPSs at the same time. Benefit from these characteristics, the batteries with VM/PP exhibits a high initial capacity of 1208.7 mAh g−1 at 0.2C and maintains at 862.4 mAh g−1 after 200 cycles. Impressively, the VM/PP shows the high specific capacity of 904.3 mAh g−1 and long-lasting cycling stability with 0.03% capacity attenuation per cycle over 600 cycles at 1.0C, demonstrating excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

In this study, polysiloxane resin was modified at the molecular scale to make it amenable to ultraviolet-curing and suitable for direct ink writing. The characterization results regarding the rheological properties and infrared spectra demonstrated that the conversion of C C is proportional to the viscosity and modulus of ink. As a result, three-dimensional cellular structures with a certain span and tailored porosity were obtained. The printed structures were then subjected to pyrolysis at temperatures higher than 1000°C to form uniform, crack-free, dense SiOC cellular ceramic structures, with ceramic yield of up to 70% and linear shrinkage as low as 25%. This technique enables the inexpensive and fast fabrication of SiOC ceramic products with relatively complex shapes. [ABSTRACT FROM AUTHOR]

At present, due to the existent trap levels, the investigation of the dual-fluorescence emission with temperature-dependency of Eu2+ and Eu3+ in long afterglow materials needs to be supplemented. In this work, Eu2+ and Eu3+ co-doped borate glass materials containing Ca/SrAl 2 O 4 crystals are successfully prepared though solid phase melting method, presenting a temperature-dependent fluorescence emission changing from blue-violet to red-orange between 300 and 500K. This interesting finding is proved to be the different thermal quenching behavior caused by the varied luminescence transition mode of Eu2+ (440 nm) and Eu3+ (614 nm). Further, the instantaneous and the delayed trap carriers release is demonstrated to moderate the thermal quenching behavior, leading to better sensing performance at high temperatures in sample of more trap distribution, with S r (max) being 1.3535% K−1 at 483K. Finally, good thermal cycling reversibility of the material shows that the temperature-dependent luminescence of Eu2+/Eu3+ assisted by traps is potential for optimizing the application of temperature sensing. [ABSTRACT FROM AUTHOR]

Abstract Thermal debinding is an important step in a gelcasting process, and the proper selection of the debinding technique is crucial for the quality of a green body. In this work, the pyrolysis characteristics of an N,N-dimethylacrylamide/N,N′-methylenebisacrylamide gel system in a thermal debinding process of a gelcast SiAlON green body were investigated through nonisothermal thermogravimetric analysis and a thermogravimetric analyzer coupled with Fourier transform infrared spectroscopy analysis. In addition, the pyrolysis kinetics of the thermal debinding process of the gelcast SiAlON green body were described by using a three-parallel-distributed activation energy model. The results showed that the conversion (α) and reaction rate (dα/dT) curves predicted by the kinetic model agreed well with the experimental data. The kinetic parameters (E 0, i , k 0, i , and σ i) of the global thermal debinding process were 116.0–158.0 kJ/mol, 9.31 × 108 s−1 and 2.19–20.52 kJ/mol, respectively. Finally, a solid–fluid–thermal–mechanical coupling numerical model of the thermal debinding process was established through finite element methods on the basis of theories of the porous medium seepage and thermodynamics. The distributions of the residual content of the gel polymer, the temperature, the pressure, and the stress in the green body throughout the entire thermal debinding process were evaluated using this model. It was shown that a high heating rate leads to a high temperature gradient and von Mises stress inside the green body. Moreover, a reasonable debinding technique was proposed to effectively prevent and eliminate defects caused by excessive stress or a temperature gradient inside the green body. In a given DMAA/MBAM gel system, the strongest stress peak can be effectively eliminated by holding at 310 °C for no less than 2 h at a heating rate of 1 °C/min. This work aims to provide a theoretical basis for studying thermal debinding kinetics and optimizing debinding techniques for the gelcasting of various materials. [ABSTRACT FROM AUTHOR]

Abstract The spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) cathode materials suffer from severe capacity fade during the charge-discharge process, which is caused by the instability of material structure under high voltage. Herein, a novel LNMO microsphere is prepared via simple co-precipitation method. The SEM images show that the LNMO spheres are constructed by many octahedral nano-particles. The structure stability of the LNMO cathode materials is improved so that the as-prepared LNMO cathode materials exhibit excellent electrochemical performance. It delivers a discharge capacity of 133.29 mA h g−1 at 0.2 C. Even the specific capacity still remains 127.46 mA h g−1 and the capacity retention rate is up to 95.6% after 300 cycles at 0.2 C. It is mainly attributed to the fact that the as-prepared LNMO materials expose the (111) crystal plane with the lowest surface energy. [ABSTRACT FROM AUTHOR]

Solid-state lithium-ion conductors suffer the disadvantages of high grain-boundary resistance. Perovskite-type LLTO was prepared via bacterial cellulose templating in this paper. BET analysis indicated that a broad range of pores formed in the LLTO templated onto bacterial cellulose. XRD examinations showed that the crystallinity of LLTO reduced upon being templated onto bacterial cellulose. SEM observations indicated that grains of LLTO pellets with bacterial cellulose became much larger and well-connected. The boundaries between grains of LLTO with bacterial cellulose became much less sharp, and the grains were almost inseparable. Under the influence of BC, the average grain-boundary thickness decreased. LLTO with 2% bacterial cellulose exhibited the highest total conductivity, 9.38 × 10−5 S/cm, which increased by 146% compared with pure LLTO. Both the reduced crystallinity and the decreased grain-boundary thickness contributed to the increase of the total conductivity by facilitating the migration of lithium ions across the grain boundaries. An electrochemical test cell of Li 4 Ti 5 O 12 //LLTO-2%BC//LiCoO 2 was demonstrated. [ABSTRACT FROM AUTHOR]

Because of their potential applications in gas sensing and catalysis, reduced graphene oxide (RGO) and ZnO have been the focus of much recent attention. However, few reported materials have been produced via the combination of hierarchical ZnO structures with RGO to achieve high sensing performances. In this paper, a hydrothermal method was used to synthesize hierarchical porous ZnO nanoflowers, which were then combined with graphene to enhance their sensing performances. The rapid detection of 1 ppm NO 2 was achieved at 174 °C. The morphologies and structures of these materials were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. Photoluminescence measurements and X-ray photoelectron spectroscopy were also used to investigate the mechanism of gas sensing by these materials. [ABSTRACT FROM AUTHOR]

Aluminum-doped zinc oxide (AZO) layers were deposited on polyethylene terephthalate (PET) flexible substrates and optimized by laser annealing using a 532 nm nanosecond pulsed laser. Effects of overlap rates, i.e. laser spot overlap rate ( SO R ) and laser scan line overlap rate ( LO R ), on AZO/PET films were investigated by X-ray diffractometer (XRD), scanning electron microscope (SEM), UV–visible transmittance spectra and digital four-point probe instrument, respectively. Laser annealing could greatly enhance grain crystallinity, increase crystallite size and avoid damage to the PET flexible substrates, thus effectively enhance transmittance and conductivity of the films. The results showed that the AZO/PET film annealed by using 85% SO R and 60% LO R presented the highest average visible transmittance of 76.2% and the lowest resistivity of 1.95×10 −3 Ω cm, which respectively improved by approximately 23% and 75% compared to those of the as-deposited AZO/PET film. This work may be of great importance from the viewpoint of performance optimization of transparent conductive oxide (TCO) flexible films. [ABSTRACT FROM AUTHOR]

Hierarchical porous mullite monoliths have been prepared via a sol–gel process accompanied by phase separation. Propylene oxide (PO) acted as an acid scavenger to mediate the gelation, poly(ethylene oxide) (PEO) as the phase-separation inducer and network former, aluminum chloride hexahydrate (AlCl 3 ·6H 2 O) as the aluminum source. The route was improved by using hypotoxic tetraethylorthosilicate (TEOS) and nontoxic aqueous colloidal silica (Aq) instead of tetramethoxysilane (TMOS). The synthesis mechanism and microstructural development were comparatively investigated by scanning electron microscopy (SEM), thermogravimetry-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and nitrogen adsorption–desorption. It was found that the mixing degree of precursors and concurrent process of gelation and phase separation are key elements to get well-defined hierarchical porous mullite monoliths. In addition, the monoliths with high relative crystallinity are more likely to be obtained under low transformation temperature in organic silicon sources system. [ABSTRACT FROM AUTHOR]

Hierarchical urchin-like hollow spheres of ZnO nanorods with reduced graphene oxide (Urc-ZGO) have been synthesized via an efficient one step solvothermal method. The ZnO hollow spheres with a size of 0.5–2 µm are anchored homogeneously on the surface of reduced graphene oxide (RGO) layers. When used as a gas sensor for detection of NO 2 , the Urc-ZGO composite shows much higher sensitivity towards NO 2 at room temperature (RT) than the corresponding RGO. It is found that Urc-ZGO hollow spheres prepared with 30 mg weight addition ratio of graphene (Urc-ZGO-30) exhibit the highest response at RT. The obvious enhancement of the gas sensing properties is attributed to the hierarchical hollow spheres in the structure of Urc-ZGO. [ABSTRACT FROM AUTHOR]

The dielectric response and electrical properties of Bi 4 Ti 2 Fe 0.5 Nb 0.5 O 12 (BTFN) ceramics have been investigated by frequency and temperature dependent dielectric/impedance spectroscopy. The detailed frequency spectrum analysis demonstrates the existence of two dielectric relaxations in the ceramics. The high-frequency relaxation is evidenced to originate from the grains and the low-frequency relaxation is ascribed to the contribution of grain boundaries. The resistance of grain boundaries is much larger than that of grains, whereas the values of capacitance of grain boundaries and grains are in the same level. Above ~340 °C, the conduction and relaxations of the material are attributed to the motion of ionized oxygen vacancies. As temperature above ~540 °C is close to the ferroelectric transition temperature, the smart dielectric response to the external applied ac field was apparently reflected by the conductance of grain boundaries, the capacitance of grains and the consequent relaxations. [ABSTRACT FROM AUTHOR]

Abstract: Silver nanoparticles (Ag NPs) were prepared on commercial fluorine-doped tin oxide (FTO) glass by direct current (DC) magnetron sputtering and thermal annealing treatment. The effects of Ag layer thickness on the morphology of Ag NPs and performance of Ag/FTO bilayer films were investigated. The annealed Ag/FTO bilayer film with a 5nm-thick Ag layer (Ag5/FTO bilayer film), which was covered with densely distributed 70-nm Ag NPs, possessed a sheet resistance of 5.7Ω/sq that is lower than that of the FTO single-layer film (8.5Ω/sq). The annealed Ag5/FTO bilayer film was selected for further optimization by coating it with sputtered aluminum-doped zinc oxide (AZO) layers. After thermal annealing, the AZO/Ag/FTO trilayer film with a 500nm-thick AZO layer had a figure of merit of 2.97×10−2 Ω−1, which is more than double that of the FTO single-layer film (1.30×10−2 Ω−1). The results indicate that the introduction of Ag NPs and AZO layer can effectively improve the overall photoelectric property of FTO single-layer films. [Copyright &y& Elsevier]

In this study, SrMoO 4 :Tb3+ phosphors were successfully synthesized for a single-band ratiometric (SBR) thermometry utilizing the redshift of CTB. The SrMoO 4 :Tb3+ phosphors have a tetragonal system owing to I 4 1 /a space group and irregular microparticles possessing a mean size of 20 μm. The incorporation of Tb3+ ions into the SrMoO 4 matrix lattice leads to a reduction in the bandgap energy owing to occurrence of defects level in gap-band. Thermal quenching concentration of Tb3+ is 1%, due to the dipole-dipole interaction between Tb3+ and Tb3+ ions. This study observed an interesting redshift in the edge of the CTB with increasing temperature, which can be explained using the configurational coordinate diagram. This phenomenon can be utilized to construct this SBR temperature measurement strategy by selecting appropriate excitation peaks or bands with different thermal responses. The study also demonstrated that SrMoO 4 : 1%Tb3+ has higher S a value of 13.31 × 10−2 K−1 @573 K and S r value of 3.54 K-1@298 K in optical thermometry, making it a suitable candidate for optical temperature measurement. [ABSTRACT FROM AUTHOR]

The thermochromic properties of vanadium dioxide (VO 2) hold great promise for applications in smart glass windows. VO 2 films exhibit a high phase transition temperature (T c), low visible transmission (T lum), and low solar modulating ability (ΔT sol), making them inadequate for the requirements of smart glass windows. While some improvement in VO 2 film performance can be achieved through single-element doping, these limited enhancements still fall short of ideal results. Therefore, there is a pressing need for the improvement of VO 2 films. In this study, we utilized the sol-gel method to prepare VO 2 samples simultaneously doped with three elements: W, Sn, and Zr. Microscopic characterization confirmed the successful incorporation of these elements. Optical measurements, including ultraviolet–visible–near-infrared spectroscopy, were conducted to assess the optical properties of the films. Ultimately, outstanding T lum (69%) and ΔT sol (14%) were achieved, along with an appropriate T c (27.6 °C). Energy consumption simulations were performed using the EnergyPlus model with experimental data, revealing that compared to conventional glass, VO 2 glass reduces total cooling energy consumption by 9.8%. In comparison to previous work, the multi-element-doped films push the performance limits of VO 2 films, offering a viable approach for fabricating superior VO 2 smart glass windows. [Display omitted] [ABSTRACT FROM AUTHOR]

Titanium niobate prepared by traditional techniques has the shortcomings of low ion diffusion coefficient as well as poor electrical conductivity, which drastically reduce its applicability. In this work, we prepare carbon coated Ti 2 Nb 10 O 29 hollow submicron ribbons (Ti 2 Nb 10 O 29 @C HSR) using a simple electrospinning procedure. As anode material for lithium-ion batteries (LIBs), it delivers a high charge capacity of 259.7 mAh g−1 at 1 C with low capacity loss of 0.013% in long-term cycles. Increased the current density to 5 C, Ti 2 Nb 10 O 29 @C HSR can maintain a reversible capacity of 189.9 mAh g−1, indicating its good rate performance. Additionally, this work uses in-situ X-ray diffraction (XRD) to provide an explanation for the lithium storage process in Ti 2 Nb 10 O 29 @C HSR, demonstrating the high reversibility during charge/discharge cycles. Therefore, Ti 2 Nb 10 O 29 @C HSR has outstanding cycle adaptability and structural reversibility to be a promising anode for LIBs. [ABSTRACT FROM AUTHOR]

Low sensitivity, long recovery times and unstable ability at high humidity has become a problem to develop humidity sensors. To overcome these problems, iron sesquioxide/carbon nanotube (Fe 2 O 3 /CNT) composite was prepared by hydrothermal technique as the humidity sensor material. The results of XRD and FI-IR reveal that Fe 2 O 3 /CNT with abundant hydrophilic functional groups are successfully synthesized. Meanwhile, First-principles (DFT) results demonstrate that Fe 2 O 3 has higher binding energy and density of states (DOS) peak shift when worked with water molecules than ferric oxide (Fe 3 O 4), indicating it has better adsorption kinetics thus to high humidity sensitivity on the surface. Furthermore, the capability of the Fe 2 O 3 material to sense humidity was investigated via hysteresis and response/recovery test. Based on the hydrophilic functional groups and high adsorption capacity for water molecules, when compared with Fe 3 O 4 -based humidity sensor, this Fe 2 O 3 /CNT device has an excellent humidity sensitivity, which display low hysteresis, good repeatability, and short response time. This work suggests that Fe 2 O 3 /CNT could be a promising candidate material for developing high-performance humidity sensor. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous Zn//MnO 2 batteries are the promising alternatives to lithium-ion batteries owing to their high safety, high energy density, low cost, and environmental friendliness. However, the unstable MnO 2 cathode causes poor practical energy density and serious capacity fading. To overcome this issue, herein, a unique 2D nanosheets self-supported 3D δ -MnO 2 microflower hierarchical architecture is rationally designed and synthesized by taking advantage of its microwave-absorbing characteristics. The 2D nanosheets with high surface area could expose numerous active sites for ions/electrons transfer. Also, the 3D assembled structure acting as building blocks would ensure structural stability for long-life cycles. Benefiting from these synergistic merits, the δ -MnO 2 microflowers deliver a high capacity of 287.6 mA h g−1 at 0.5 C, an excellent rate capability of 202.7 mA h g−1 at 5 C, and a superior cycling retention of 76.5% over 1000 cycles at 10 C. Furthermore, a storage mechanism of H+/Zn2+ co-insertion accompanied by the deposition of zinc sulfate hydroxide hydrate is clarified by the aid of ex-situ XRD and SEM technologies. This work provides a new pathway for developing high capacity and long lifespan ZIBs. [Display omitted] [ABSTRACT FROM AUTHOR]

To prevent bacterial contamination and enhance wear-resistance of titanium-based tools and implants, it is crucial to develop functional coatings with inherent antimicrobial property and high surface hardness. In this study, the micro-arc oxidation technique was employed to prepare ceramic oxide films with antibacterial properties on titanium metal surfaces by incorporating trace amounts of copper. It was found that the phytic acid (C 6 H 18 O 24 P 6) used as the chelating agent in the Cu-containing electrolyte can not be recycled and the adding of alternative chelating agent calcium gluconate (C 12 H 22 O 14 Ca) can significantly promote the cyclic utilization. The oxide film prepared by using C 12 H 22 O 14 Ca as the chelating agent exhibits a typical volcanic micro-arc oxidation morphology with uniform copper distribution, high hardness and excellent substrate adhesion. Most importantly, in vitro antibacterial tests demonstrate the outstanding antibacterial performance of Cu-doped TiO 2 film with an antibacterial rate of up to 99.9% against Escherichia coli and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

To prevent bacterial contamination and enhance wear-resistance of titanium-based tools and implants, it is crucial to develop functional coatings with inherent antimicrobial property and high surface hardness. In this study, the micro-arc oxidation technique was employed to prepare ceramic oxide films with antibacterial properties on titanium metal surfaces by incorporating trace amounts of copper. It was found that the phytic acid (C 6 H 18 O 24 P 6) used as the chelating agent in the Cu-containing electrolyte can not be recycled and the adding of alternative chelating agent calcium gluconate (C 12 H 22 O 14 Ca) can significantly promote the cyclic utilization. The oxide film prepared by using C 12 H 22 O 14 Ca as the chelating agent exhibits a typical volcanic micro-arc oxidation morphology with uniform copper distribution, high hardness and excellent substrate adhesion. Most importantly, in vitro antibacterial tests demonstrate the outstanding antibacterial performance of Cu-doped TiO 2 film with an antibacterial rate of up to 99.9% against Escherichia coli and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

In this work, La 2 NiMnO 6 , which exhibits a remarkably unique combination of ferromagnetic properties and high resistivity, was employed as an insulation coating to improve the magnetic properties of iron-based soft magnetic composites (SMCs). La 2 Ni x Mn 2-x O 6 (x = 0.4–1.6) were synthesized via the sol-gel method at different temperatures (500–700 °C). The optimal crystallinity and magnetic properties were observed at 700 °C with x = 1, thus La 2 NiMnO 6 synthesized under these specific conditions was utilized as an insulation coating medium. With the increase of La 2 NiMnO 6 , the saturation magnetization of La 2 NiMnO 6 /Fe SMC gradually decreases; however, this decrease is minimal due to the inherent ferromagnetic properties of La 2 NiMnO 6. As La 2 NiMnO 6 increases, the effective permeability of La 2 NiMnO 6 /Fe SMC initially increases and then decreases, while the core loss initially decreases and then increases. The highest effective permeability and lowest core loss are achieved at a coating amount of 1.2 wt%. As the operating temperature increases from −40 °C to 100 °C, the permeability gradually increases while losses decrease, making it suitable for use as a power device. [ABSTRACT FROM AUTHOR]

Here Pt loaded SnO 2 –Co 3 O 4 composite was fabricated using a hydrothermal method and was applied to gas sensing for the first time. The structure, morphology, surface and gas sensing property of the sensing composites were respectively studied by XRD, SEM, HRTEM (Mapping), BET, XPS and electrochemical workstation. The gas sensing results showed that the response value of 1%Pt loaded SnO 2 /5%Co 3 O 4 to hydrogen gas was 57.9, which was 9.6 times of pristine SnO 2. And the response time of 1%Pt-loaded SnO 2 /5%Co 3 O 4 to hydrogen was 12 s, which was much faster than that of pristine SnO 2. The material also exhibited other excellent sensing performance such as selectivity for detecting H 2 gas. Based on the experiments, the improved H 2 sensing properties was due to synergistic effect of the spillover effect of Pt element and the formation of p-n junction. This work will provide valid method to fabricate SnO 2 -based gas sensing materials for real application to detect target gas. • Pt loaded SnO 2 –Co 3 O 4 was fabricated and applied to gas sensor for the first time. • The response of 1%Pt loaded SnO 2 /5%Co 3 O 4 to 100 ppm H 2 reached 57.9. • The synergistic effect of Pt and Co elements are discussed. • The average size of 1%Pt loaded SnO 2 /5%Co 3 O 4 composite is only 6 nm. (Debye length). • The sensor has excellent sensing selectivity to H 2 against the tested interfering gases. [ABSTRACT FROM AUTHOR]

SiBCN ceramic aerogels have excellent properties such as ultra-high temperature stability, low density and high thermal insulation. The aerogels have better potential applications in aerospace and other fields. However, similar to inorganic aerogels, the low mechanical strength of SiBCN ceramic aerogels are the main limitation of its application. Based on the principle of inorganic double network enhancement, the first network was constructed by PVA and HNTs, and HNTs/SiBCN dual network aerogels were constructed by SiBCN ceramic aerogels as the second network. The structure and mechanical properties were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), specific surface area analyzer and pressure tester. Compared with SiBCN ceramic aerogels, 6 wt% HNTs-SiBCN ceramic hybrid aerogels have better microscopic properties (maintaining basic porous network structure and structural stability) and mechanical properties.The continuous HNTs first network can effectively transfer the stress load and enhance the strength of SiBCN ceramic aerogels. [ABSTRACT FROM AUTHOR]

LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) is a typical nickel (Ni)-rich ternary cathode material with several advantages, such as high specific capacity, low-cost, and environmentally friendly, making it a good candidate for use in lithium-ion batteries. However, its Ni content is as high as 80%; therefore, several new problems have emerged with gradually increasing applications. In this review, Li–Ni disorder and corresponding modification methods are first briefly reviewed, and then the origin of complex surface defect, which has a crippling effect on diffusion processes of Li+ at electrolyte/cathode interface, is discussed in detail. Analyses showed the importance of selecting appropriate surface modification material/technique for enhancing electrochemical properties. Therefore, popular surface coating materials and methods including metal oxides, fluorides, phosphates, fast ion conductors, and other compounds/elements used for the development of NCM811 are subjected to extensive and thorough research. Finally, several new perspectives and insights related to stability and safety at high voltages and temperatures, and the optimization of production process are also proposed. [ABSTRACT FROM AUTHOR]

For a long time, rare-earth ion-doped phosphors have been widely used in temperature sensing because of their excellent light-emitting properties. However, most of the rare earth elements are relatively rare and expensive, so the transition group elements that are economical and easy to obtain have been favored by researchers. This paper presents a new type of phosphor doped with rare earth ion and transition metal for optical temperature measurement. In recent years, Mn4+-doped phosphors have attracted wide attention because of their strong deep red light-emitting properties. La 2 LiSbO 6 provides a good host environment for Mn4+ and Eu3+ due to its unique crystal structure. In this paper, a series of La 2 LiSbO 6 phosphors singly doped with Mn4+ and Eu3+, and co-doped with Eu3+/Mn4+ were synthesized. The crystal phases and optical properties of these materials were characterized and analyzed in detail. We specifically studied the temperature dependence of the fluorescence intensity of the optimized La 2 LiSbO 6 : Eu3+, Mn4+ phosphors at 303K–523K. The experimental results prove that the thermal responses of Mn4+ and Eu3+ are different. With increasing temperature, the thermal quenching of the Mn4+ fluorescence intensity is much faster than that of Eu3+, so the temperature characteristics can be explored by the fluorescence intensity ratio (FIR) of Eu3+ to Mn4+. At 523 K, its maximum relative sensitivity and maximum absolute sensitivity can reach 0.891% K−1 and 0.000264 K-1, respectively. Our experimental analysis shows that La 2 LiSbO 6 :Eu3+/Mn4+ phosphors have relatively high temperature sensitivity and have potential application prospects in the field of high temperature sensing. [ABSTRACT FROM AUTHOR]

The serious reaction between Mn in molten steel and SiO 2 in calcium silicate-based mold flux during continuous casting of Al-free high-Mn cryogenic steels could change the mold flux properties and in-mold performance. In this study, the combination of rotating viscometer, FTIR spectroscopy, Raman spectroscopy and O 1s X-ray photoelectron spectroscopy (XPS) was employed to get a deep insight into the effect of the reaction levels characterized by MnO/SiO 2 ratios on the viscosity and structure of mold fluxes. The results exhibit that the transformation of mold flux from Newtonian fluid to non-Newtonian fluid can be reflected by viscosity change with varying rotation speeds. The viscosity decreases continuously with increasing MnO/SiO 2 ratio but the temperature dependence of viscosity decreases at high MnO/SiO 2 ratio. Structural information from FTIR revealed the slag system is mainly a silicate structure. The deconvoluted results of Raman spectra show an increase in NBO/Si, amounts of Q0 ([SiO 4 ]4–) and Q1 ([Si 2 O 7 ]6–) units with increasing MnO/SiO 2 ratio, whereas a decrease in amounts of Q2 ([SiO 3 ]2–) and Q3 ([Si 2 O 5 ]2–) units in the meantime, this indicates the depolymerization of the silicate structure with proceeding of the slag/steel reaction. According to semiquantitative analysis of XPS spectra, the relative proportion of bridge oxygen (O0) decreases at the cost of non-bridged oxygen (O–), which suggests that the silicate structure gradually depolymerizes. The structural analysis supports the change of viscous behavior of mold flux with slag/steel reaction. [ABSTRACT FROM AUTHOR]

CaMoO 4 :Pr3+ thermochromic phosphors with diverse thermal responses for temperature sensing were prepared by the traditional solid-phase reaction method. The typical CaMoO 4 :Pr3+ had scheelite structure belonging to tetragonal crystal system and space group of I 4 1 / a (88). Pr3+ ions can be easily substituted for Ca2+ ions of host CaMoO 4 because of similar ionic radius. CaMoO 4 : 1.5% Pr3+ have the block structure with mean size of 6.84 μm. The E g (∼3.93 eV) value of pure CaMoO 4 is bigger than that (∼3.65 eV) of CaMoO 4 : 1.5%Pr3+, attributing to the existence of intermediate defect energy levels. Appropriate Pr3+ doping concentration is 1.5%, and the concentration quenching phenomenon can be explained by the concrete electric multipole type of d-d interaction. The emission peak at ∼605 nm from 1D 2 →3H 4 transition have a good thermal stability of 99.452%@423 K, while the wide band centered at ∼490 nm from 3T 1,2 → 1A 1 transition in the MoO 4 2− complex and 3P 0 →3H 4 transition in Pr3+ have a poor thermal stability of 27.572%@423 K. Calculated activation energy is 0.239 eV. Temperature-dependent FIR for optical thermometry was constructed due to their diverse thermal responses. CaMoO 4 : Pr3+ phosphor had good relative sensitivities of 2.216%, 0.969% and 0.932% based on FIR of I 605 nm /I 490 nm with Boltzmann distribution, modified Boltzmann distribution and exponential equation fitting. Thermochromic behavior and thermal quenching mechanism are investigated. The obtained relative sensitivity is better than that of most phosphors, implying that CaMoO 4 : Pr3+ has a potential for application in optical thermometry. [ABSTRACT FROM AUTHOR]

This study focused on utilizing a boron nitride (BN) layer to improve the photoelectric property stability of the flexible Al/Cu/ZnO multilayer thin film, which was prepared on a polyethylene terephthalate (PET) substrate by radio frequency (RF) magnetron sputtering. By analyzing surface morphology, chemical composition and photoelectric properties of flexible BN/Al/Cu/ZnO multilayer films with different BN layer thicknesses, the BN/Al/Cu/ZnO film with a 100-nm-thick BN layer (BN 100 /Al/Cu/ZnO), which had the best comprehensive photoelectric property with a figure of merit of 0.82 × 10−3 Ω−1, was chosen to further study the performance stability with storage temperature and time. It was found that as compared to the Al/Cu/ZnO film, the BN 100 /Al/Cu/ZnO film had more stable photoelectric properties at different storage temperatures and times, which was inferred to be attributed to the excellent heat and oxidation resistances of the BN layer that were conducive to avoiding surface damage and oxidation of the film. The results in this work demonstrate the key role of the BN layer in enhancing photoelectric property stability of the flexible Al/Cu/ZnO film, and may provide a feasible strategy for improving thermal and long-time stability of single-layer or multilayer flexible transparent conductive films. [ABSTRACT FROM AUTHOR]

Particle size plays an important role in the electrochemical properties of cathode materials for lithium-ion battery, and the sizes of cathode powders are often designed to specific scales to obtain desired rate capacity, cyclic stability, etc. Nano-sized or micron-sized primary/secondary particles were both reported to be helpful to heighten the electrochemical properties of the same material system. However, the relationship between particle size and electrochemical properties of Ni-rich LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM-811) has not been discussed in detail. Here, we prepared the pristine NCM-811 powders with various micro-sized particles by using solid state reaction, and investigated the influence of particle size on the electrochemical properties of typical NCM-811 cathode material, to clarify the importance of size effect. The result indicates that pristine NCM-811 cathode powders with D 50 = 7.7 μm displayed the best initial discharge specific capacity (224.5 and 169.1 mA h/g at 1/20 C and 1 C rate, respectively) and retention capacity (71.0% at 1 C rate) after 100th cycling at room temperature. The mutual acting mechanism in terms of layered structure, cation mixing degree, polarization state, charge-transfer resistance, and the diffusion ability of lithium-ion was confirmed by XRD, XPS, CV and EIS analyses, respectively. [ABSTRACT FROM AUTHOR]

In this study, the effects of A-site La and Ca defects with Mn2+ doping on the structure, magnetic phase transition, magnetocaloric effect, critical indices, and magnetic interactions of La 0.66-x Ca 0.33-y Mn 1+x + y O 3 porous nanospheres were investigated. The results indicated that the critical parameters of La 0·66 Ca 0·33 MnO 3 porous nanospheres were similar to those of the short-range ordered Ising model. The A-site La-defect Mn2+ doping makes the critical parameters β and γ tend to the Ising model and mean-field model, respectively. When A-site Ca-defect Mn2+ doping is obtained, β and γ tend to follow the Ising model and 3D-Heisenberg model, respectively. The phase transition exhibited a second-order ferromagnetic-paramagnetic transition for all samples. The A-site defect Mn2+ doping in La 0.66-x Ca 0.33-y Mn 1+x + y O 3 porous nanospheres enhanced the Curie temperature to near room temperature without affecting magnetic entropy change. The effect of A-site defect Mn2+ doping on the magnetic interaction of La 0.66-x Ca 0.33-y Mn 1+x + y O 3 was visualized by the first-order reversal curve. The variation of interaction field distribution at the Curie temperature and 300 K indicated that exchange interaction was dominant at high temperature and dipole interaction was dominant at the Curie temperature. [Display omitted] • Non-stoichiometric La 0.66-x Ca 0.33-y Mn 1+x + y O 3 porous nanospheres were prepared using a solvothermal method. • The role of Mn2+ doped in La 0.66-x Ca 0.33-y Mn 1+x + y O 3 porous nanospheres were investigated. • The Mn2+ doping in La 0.66-x Ca 0.33-y Mn 1+x + y O 3 porous nanospheres enhanced the T C to near RT without affecting | -ΔS M max |. • The changes in magnetic interaction of La 0.66-x Ca 0.33-y Mn 1+x + y O 3 porous nanospheres were visualized by FORC. [ABSTRACT FROM AUTHOR]

Rational composition and structural design of electrode substances are critical for lithium-ion batteries (LIBs) and supercapacitors (SCs) with good cycling steadiness and superb rate capability. Therefore, we report a novel electrode material consisting of V 2 O 3 quantum dots (QDs, about 6.64 nm) well-distributed on mesoporous carbon (MC) nanosheets. V 2 O 3 has high intrinsic conductivity and an open tunnel-like lattice structure, facilitating electron transfer and ion intercalation. The composite architectures can offer more electrochemical active sites, shorten ion/electron diffusion paths, and reduce volume swings during the charging/discharging process. The synergic effect of these merits significantly improves the reaction kinetics and prevents structural damage to the entire electrode. As a result, V 2 O 3 -QDs/MC nanosheets exhibit a large capacity/capacitance, excellent cycling steadiness, and high rate performance. For LIBs, V 2 O 3 -QDs/MC displays a great reversible capacity of 931 mAh g−1 at 0.2 A g−1 over 500 cycles and fast and stable lithium storage behaviors with 822 mAh g−1 at 2 A g−1 after 1000 cycles. For SCs, V 2 O 3 -QDs/MC manifests a considerable specific capacitance of 270 F g−1 at 1 A g−1 and satisfactory durability for at least 5000 cycles at 10 A g−1. This work informs a good structure design for constructing advanced metal oxide-based nanostructured electrode materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Hollow graphene spheres are successfully prepared and employed as the separator coating materials for lithium-sulfur batteries. The hollow graphene spheres coated separator has been proven an efficient trap to adsorb and block polysulfide, greatly alleviating the shuttle effect. In the case of using elemental sulfur as cathode active material and the weight of the diaphragm is only increased by 10.3%, the lithium-sulfur battery with hollow graphene spheres coated separator delivers a high initial specific capacity of 1172.3 mAh g−1 at the current density of 0.2 C, and the discharge capacity remains at 829.6 mAh g−1 after 200 cycles with a capacity decay of 0.146% per cycle, showing excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

Abstract An ultrasonic-vibration-assisted laser annealing method was developed to enhance the performance of fluorine-doped tin oxide (FTO) thin films. The influences of ultrasonic vibration, laser scan line overlapping rate (L OR) and laser spot overlapping rate (S OR) on surface morphology, FTO layer thickness, RMS roughness, crystal structure and photoelectric properties of the FTO films were investigated. The results indicated that the presence of ultrasonic vibration during laser annealing could significantly enhance the film compactness, and using moderate L OR and S OR values resulted in significantly decreased FTO layer thicknesses and RMS roughnesses as well as slightly increased crystallite sizes, thus yielding significantly improved optical transmittance values and slightly enhanced electrical conductivity values. It was found that the optimal L OR and S OR values for ultrasonic-vibration-assisted laser annealing of the FTO films were 80% and 90%, respectively. The as-obtained film possessed the best overall photoelectric property with an average transmittance (400–800 nm) of 85.9%, a sheet resistance of 8.7 Ω/sq and a figure of merit of 2.51 × 10–2 Ω–1. This work may be of great significance in terms of performance optimization of transparent conducting oxide (TCO) thin films. [ABSTRACT FROM AUTHOR]

Metal sulfide CoS 2 is prepared and used as host materials for Li-S batteries. The CoS 2 particle could immobilize the polysulfide by catalyzing the redox reactions of soluble polysulfide to insoluble polysulfide. Besides, the employment of vapor growth carbon fiber (VGCF) interlayer between CoS 2 /S cathode and separator has a positive effect on physically adsorbing polysulfide. Consequently, the chemical and physical adsorption could exist in one Li-S battery system at the same time. As a result, the initial discharge capacity of CoS 2 /S composite cathode with VGCF interlayer is 1278 mAh g −1 at the rate of 0.1 C. After 200 cycles, the capacity still remains as high as 701 mAh g −1 , which is better than the battery without CoS 2 , showing excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

In order to improve the properties of white light-emitting diodes (WLEDs), a number of phosphors have been investigated. In this study, a variety of SLGO phosphors doped with Bi3+/Eu3+, Bi3+/Tb3+, and Bi3+/Eu3+/Tb3+ ions were synthesized by the solid-state reaction method. The crystal structure, site occupancy of the SLGO host, and the phase composition of the synthesized phosphors were discussed. The optical properties of the synthesized phosphors were characterized by UV–vis, PLE and PL techniques. The relative PL mechanisms and energy transfer (ET) processes (Bi3+→Eu3+, Bi3+→Tb3+ and Tb3+→Eu3+) were discussed in detail. In addition, the CIE chromaticity coordinates of these phosphors were calculated. Tunable PL has been achieved througth adjusting the concentrations of three doping ions and ET process. The ET process was verified by the fluorescence lifetime test. The thermal stability of the phosphor was also studied and discussed. Finally, a WLED device was fabricated by combining the SLGO:Bi3+/Tb3+/Eu3+ phosphor with a 275 nm LED chip, and the electroluminescence was measured. The values of CCT and CRI were 5263 K and 78, respectively. The results demonstrate that the synthesized phopshors have potential applications in the field of WLEDs. [ABSTRACT FROM AUTHOR]

In the present work, YSZ TBCs and 10 wt% CeO 2 -doped YSZ thermal barrier coatings (CeYSZ TBCs) were prepared via atmospheric plasma spraying(APS) respectively, whereupon high temperature oxidation experiment was carried out at 1100 °C to compare the high temperature oxidation behavior and mechanism of the two TBCs. The results showed that the doping of CeO 2 reduced the porosity of YSZ TBCs by 23%, resulting in smaller oxidation weight gain and lower TGO growth rates for CeYSZ TBCs. Besides, the TGO generated in CeYSZ TBCs was obviously thinner and there were fewer defects inside it. For YSZ TBCs, as the oxidation process proceeded, Al, Cr, Co and Ni elements in the bonding coating were oxidized successively to form loose and porous spinel type oxides (CS), which was apt to cause the spalling failure of TBCs. While, the Al 2 O 3 layer of the TGO generated in CeYSZ TBCs ruptured later than that in YSZ TBCs, which delayed the oxidation of Cr, Co, and Ni elements and the formation of CS accordingly. Therefore, CeO 2 doping can effectively improve the high temperature oxidation resistance of YSZ TBCs. [ABSTRACT FROM AUTHOR]

Commercial fluorine-doped tin oxide (FTO) thin films were subjected to laser annealing coupled with ultrasonic vibration (48 kHz and 350 W). The effects of ultrasonic vibration, laser fluence and defocusing amount were systematically studied. Laser annealing could result in grain growth or damage of the FTO layer, and introducing ultrasonic vibration during laser annealing could effectively enhance the film compactness, decrease the film thickness and refine the grains in the film. As a result, the optical and electrical properties of the ultrasonic-vibration-assisted laser-annealed FTO films were significantly improved by using low laser fluences and high defocusing amounts, and were slightly deteriorated when high laser fluences and low defocusing amounts were adopted. The results indicated that the film obtained by ultrasonic-vibration-assisted laser annealing using a laser fluence of 0.6 J/cm 2 and a defocusing amount of 2.0 mm had the best overall photoelectric property with an average transmittance of 84.1%, a sheet resistance of 8.9 Ω/sq and a figure of merit of 1.99×10 –2 Ω –1 , outperforming that of the film obtained by pure laser annealing using the same experimental parameters. The present study confirms the efficacy of ultrasonic-vibration-assisted laser annealing in optimizing performance of FTO films. [ABSTRACT FROM AUTHOR]

The 0.5Bi 4 Ti 3 O 12 -0.5BiFe 0.98 Mn 0.02 O 3 (BTBF) composite film based on fluorine doped tin dioxide (FTO)/glass was prepared by the sol-gel method. The structure, oxygen vacancy concentration, electrical properties and aging of BTBF composite films were tested and analysed at various annealing temperatures (T = 570, 585, 600, 615, 630 °C). X-ray diffraction (XRD) analysis indicated that Bi 4 Ti 3 O 12 and BiFe 0.98 Mn 0.02 O 3 formed an Aurivillius structure with a 4-layer perovskite structure after being made into a solid solution, and the crystallinity of the sample at T = 615 °C was better. The scanning electron microscope (SEM) results showed that the average crystal size of the samples increased with increasing annealing temperature. X-ray photoelectron spectroscopy (XPS) fitting results indicated that the specimens all had oxygen vacancy defects and that the concentration of oxygen vacancies in the specimens was lower at T = 615 °C. By analysing the electrical properties of the BTBF composite film, it was found that the samples at 615 °C had better ferroelectricity and lower leakage current density, the remnant polarization intensity (2P r) was approximately 31.1 μC/cm2, the coercive field intensity (2E c) was approximately 682.1 kV/cm, and the leakage current density was approximately 1.3 × 10−5 A/cm−2 when the electric field was 400 kV/cm. In addition, the aging of the samples was analysed, and it was found that the samples underwent different degrees of aging. The aging mechanism is also discussed. [ABSTRACT FROM AUTHOR]

Crack generation and propagation in refractories is inevitable during their service life, which ultimately contributes to their failure. Accordingly, this study proposes a method that includes a watershed algorithm and classification criterion to quantitatively evaluate the fracture behavior in refractories. Additionally, to demonstrate the stability and reliability of the algorithm, its crack analysis results were compared with those of manual methods for alumina-magnesia ramming materials and corundum castables. The results indicated that the algorithm was capable of automatically identifying, extracting, and classifying cracks. Additionally, the type of crack propagation and its length and width were analyzed to determine the performance and properties of refractories. The proposed method was highly effective and accurate for the automated evaluation of material fracture behavior. [ABSTRACT FROM AUTHOR]