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Studied the microwave absorption performance of carbon fiber, mixed carbon fiber/MoSe 2 (CM) bilayer composite materials in the range of 2–18 GHz. The flower-shaped layer and core-shell double-layer interface of MoSe 2 work together to improve electromagnetic wave absorption, providing a new approach for designing lightweight, broadband, and strong absorption-absorbing materials. To address the drawbacks of the high conductivity of pure carbon fibers, transition metal sulfides were introduced promptly, and the CM core-shell materials with flower-shaped outer shell structures were prepared. An in-depth analysis of the working mechanism of CM absorbing materials and the influence of the interface between carbon fibers and MoSe 2 on the absorbing performance has been conducted, providing a favorable experimental basis for the application of fiber membranes in absorbing materials. [Display omitted] • Easy preparation of carbon fiber @ MoSe 2 (CM) through electrospinning. • Compared with pure carbon fiber, the microwave absorption ability of CM is greatly enhanced. • The CM achieved a reflection loss of −41.8 dB, with an effective absorption bandwidth of 5.23 GHz. [ABSTRACT FROM AUTHOR]

Abstract The 3D microsheets contain cobalt particles and numerous interlaced carbon nanotubes (denoted as Co-NCNTs) with different pyrolysis temperature (700 °C, 800 °C and 900 °C) were successfully fabricated by a novel solution phase method. That is, polyolized the prepared g-C 3 N 4 to form a g-C 3 N 4 @Co-glycolate hybrid precursor microsheets, which was then subjected to pyrolysis treatment under an inert gas. The effects of pyrolysis temperature in the range of 700°C–900 °C on the microwave absorption properties of the Co-NCNTs were investigated in detail. As an absorber, Co-NCNTs with the pyrolysis temperature of 800 °C exhibit superior electromagnetic wave absorption properties with the optimal reflection loss (R L) value of −46 dB in the thickness of 2.5 mm, wide effective bandwidth (R L ≤ −10 dB) of 7.2 GHz. This excellent performance attributed to the special microsheet structures, uniform Co particle distribution and the better impedance matching. Highlights • The 3D Co-NCNTs microsheets were fabricated by a novel solution phase method. • The MW absorption properties at different pyrolysis temperature were investigated. • Many interlaced N-CNTs and Co particles are entwined on the surface of microsheets. • The maximum R L of Co-NCNTs/800 °C is −46 dB at the thickness of 2.5 mm. • The uniform Co particle distribution contribute to the enhancement of ability. [ABSTRACT FROM AUTHOR]

Abstract Flexible electrodes with light weight, favorable mechanical strength and high energy/power density have attracted tremendous interest for next-generation lithium-ion batteries. Here we develop a novel architecture for preparing a freestanding binder-free flexible electrode (Hierarchical SnS 2 Nanoplates Decorated on the Graphene Supported by Carbon Cloth), which possesses superhigh mass-loading and large specific surface area. The electrode provides the high-rate transportation of electrolyte ions and electrons throughout the electrode matrix and buffers the volumetric expansion effect generated from Li+ insertion/desertion. The uniform size and homogeneous SnS 2 nanoplates on the graphene nanosheets reduced electrode polarization, leading to excellent electrochemical performance. The flexible electrode exhibits an extraordinary initial capacity of 1987.4 mAh g−1, a specific capacity up to 638.1 mAhg−1 after 150 cycles, which integrates that the design strategies to enhance the mass loading of active materials can be responsible for the superior lithium storage performance. Highlights • An insight into design for binder-free SnS 2 /graphene/carbon cloth flexible electrodes. • The electrodes possess larger specific surface area and higher mass loading. • The hierarchical SnS 2 and cross-linking graphene accelerate the transportation of ions and electrons. • The optimized anodes exhibit high specific capacity and stable cycling performance. [ABSTRACT FROM AUTHOR]

Abstract A ternary composite material FeCo@SiO 2 @PPy with high-performance electromagnetic absorption have been successfully synthesized and characterized. In this paper, the components, structure and morphology of the FeCo@SiO 2 @PPy have subsequently tested by XRD, TEM and SEM. The electromagnetic wave parameters of the composite was detected by the vector network analyzer (VNA). The reflection loss (R L) of FeCo@SiO 2 @PPy composites reaches −65.17 dB with the thickness of 2.1 mm at 16.48 GHz and the absorption frequency bandwidth R L -10 dB was up to 6.8 GHz (10.4 GHz–17.2 GHz) with the layer of 2.5 mm. The absorption frequency bandwidth lower than −10 dB is up to 13.12 GHz with the range of thickness from 2.1 to 5.0 mm. Highlights • The FeCo@SiO 2 @ PPy was fabricated using a sample two-step method. • The maximum R L value of FeCo@SiO 2 @PPy is up to −65.17 dB at 16.48 GHz. • The absorption bandwidth with R L below −10 dB is achieved 6.8 GHz. • The R L of FeCo@SiO 2 @PPy composite are significantly enhanced compared with FeCo@SiO 2. [ABSTRACT FROM AUTHOR]

A simple synthesize method of hybrid transition metal oxides is important for the application of electrodes materials. In this work, we report one-pot hydrothermal method to synthesize 3D hierarchical MnMoO 4 /NiWO 4 microspheres. Notably, the 3D hierarchical MnMoO 4 /NiWO 4 microspheres electrodes with a MnMoO 4 /NiWO 4 molar ratio of 4:3 present outstanding electrochemical performance. The excellent specific capacitance of the hybrid materials is 598 F g -1  at a discharge current density of 1 A g −1 and the capacitance retains 82% of its initial capacitance even after 5000 cycles, which are attributed to the obtained 3D hierarchical MnMoO 4 /NiWO 4 microspheres are constituted by self-assembly MnMoO 4 nanoflakes and NiWO 4 nanoparticals and feature with abundant transportation shortcuts for electrolyte ions and excellent electrochemical performance. The results reveal that the 3D hierarchical MnMoO 4 /NiWO 4 microspheres have great application prospect for electrochemical energy storage and the quick and facile method provides a new avenue for the preparation of hybrid materials. [ABSTRACT FROM AUTHOR]

In this work, a microporous and high surface area carbon material with excellent electron conductivity is synthesized through carbonizing and activation processes using waste shaddock wadding. Because of the unique multi-hole, thin sheets cluster and irregular wrinkled surface coexisting structure, the shaddock wadding carbon-sulfur (SWD-S) composite can be used as a kind of cathode material for rechargeable lithium-sulfur batteries by loading element sulfur into the shaddock wadding activated carbon via simple heat treatments. Because of the high specific surface area of SWD (1637.3 m 2 g −1 ), the SWD-S composite has a sulfur content about 73.7 wt%, and delivers a high initial discharge capacity of 1050 mAh g −1 at a rate of 0.2C. Moreover, SWD-S composite exhibits a good rate capacity and excellent cycle ability. Over 200 cycles it achieves with a high columbic efficiency around 95%. After 200 cycles at 0.2C, it still remains a capacity of 599 mAh g −1 . [ABSTRACT FROM AUTHOR]

To address the issues of existing powder metallurgy particle reinforced composites, such as poor wettability between ceramic reinforcement and Al matrix, the toxicity of quasicrystal, the compositional limitations of high entropy alloy, and poor thermal stability of amorphous alloy reinforcement, etc. Al matrix composites reinforced with Co-based hard particles (M7) were synthesized by a powder metallurgy process. The effects of sintering temperature, M7 hard particle content, and particle size on the microstructure and mechanical behavior of the composites were investigated. The results show that as the sintering temperature rises, the interdiffusion reaction between M7 particles and Al matrix is enhanced, the diffusion layer becomes thicker, the in-situ generated intermetallic compounds such as Al 3 Ni 2 , Al 13 Cr 2 , Co 2 Al 9 and Al 72.5 Co 16.5 Ni 11 become more abundant, and parts of M7 particles gradually dissolve in the Al matrix and the interdiffusion layer disappeared. When the sintering temperature was raised from 580°C to 640°C, the microhardness and yield strength were improved from 23.9 to 34.7 HV 0.1 and 40.9–175.2 MPa, respectively. The composites' microhardness and strength increase as the M7 particle content increases. Meanwhile, the smaller the particle size, the greater the microhardness and yield strength. The strengthening mechanism of M7/Al composites is mainly attributed to the synergistic effects of the in-situ generated multiphase intermetallic compounds strengthening, solid solution strengthening, and M7 hard particles dispersion strengthening. Furthermore, the M7/Al composites' microhardness and strength were respectively 27.6% and 146.1% higher than those of the SiC/Al composites containing the same size and content of SiC particles, which is mainly due to the good interfacial wettability between M7 and Al matrix. It indicates that metal-based hard particles could be better alternative reinforcements to produce high performance composites. • Al matrix composites reinforced with Co-based hard particles were synthesized by PM. • There was a significant improvement in the mechanical properties of the M7 /Al composites. • The synergistic reinforcement mechanism for M7 /Al composites is proposed. [ABSTRACT FROM AUTHOR]

Three-dimensional graphene@carbon nanotube (G@CNT) composite was coated on polypropylene separator as an interlayer for high performance of lithium-sulfur batteries. In this study, the novel G@CNT nanotubes coated separator offers not only fast electron pathway for insulating sulfur, but also outstanding restriction of dissolving polysulfides. The heat impregnation of sulfur in carbon black also plays an auxiliary role on the cycling performance of the G@CNT interlayer assisted cathodes. As the dual sulfur locking strategy by heat impregnation and G@CNT interlayer, the prepared Li-S cells exhibited high rate capacity and sustainably enhanced cycling stability. Excellent cycling performance with a high capacity 935.1 mAh g −1 at 0.2C and 755.6 mAh g −1 at 1C after 200 cycles is achieved. Moreover, the cell delivers reversible discharge capacities up to 669.7 mAh g −1 and 555.1 mAh g −1 after 200 cycles even at 2C and 4C. [ABSTRACT FROM AUTHOR]

In this paper, we report the original synthesis of hollow Si-Ni 3 Sn 2 @ graphene composite and its high reversible capacity as lithium-ion battery anodes. To build the new architecture, three strategies of hollow architectures, porous surface and specific composition of graphene are attempted to develop lithium storage with far greater energy density and outstand rate performance. The results show that as-designed hollow Si-Ni 3 Sn 2 @graphene composites exhibit outstanding reversible capacity of 855.7 mAh g −1 during the first cycle, and 576.6 mAh g −1 can be maintained during a cycling test of 50 cycles at 300 mA g −1 . The rate capability is also enhanced, delivering reversible capacity of 449.8, 420.4, 392.7 and 377.1 mAh g −1 at current densities of 600, 800, 1200 and 1800 mA h g −1 , thus exhibiting great potential as an anode material for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

The reduced graphene oxide (RGO)/CoFe 2 O 4 magnetical nanocomposites have been successfully fabricated via a facile method combining co-precipitation and hydrothermal process. The TEM results show that the CoFe 2 O 4 nanoparticles with diameters about 10–20 nm are well dispersed on the entire graphene nanosheets without aggregation. In this work, the CoFe 2 O 4 nanoparticles were used to bring magnetic loss ability, while the graphene nanosheets were designed to bring dielectric loss ability. It could enhance impedance matching characteristic, further improving the electromagnetic (EM) wave absorption performance. Therefore, the as-prepared RGO/CoFe 2 O 4 nanocomposites exhibit excellent EM wave absorption properties in terms of both the maximum reflection loss and the absorption bandwidth. The maximum reflection loss of RGO/CoFe 2 O 4 nanocomposites is −53.6 dB at 11.4 GHz with the thickness of 2.5 mm and the maximum absorption bandwidth with the reflection loss below −10 dB is up to 5.0 GHz (from 12.2 to 17.2 GHz) with the thickness of 2.0 mm. And also the absorption bandwidth with the reflection loss below −10 dB is up to 13.5 GHz (from 4.5 to 18.0 GHz) with a thickness in the range of 1.5–5.0 mm. The above results all suggest that the RGO/CoFe 2 O 4 nanocomposites can serve as an ideal candidate for an efficient broad band EM wave absorber. [ABSTRACT FROM AUTHOR]

Nitrogen and sulfur co-doped graphene supported hollow ZnFe 2 O 4 nanosphere composites have been successfully synthesized via a facile, two-step hydrothermal method. The obtained ZnFe 2 O 4 /NSG samples show interconnected hollow sphere nanostructure with a size of ∼250 nm. The product demonstrated a high initial discharge capacity of 2478.6 mAhg −1 at a rate of 300 mAg −1 . After 100 cycles, it delivered a high reversible capacity of 729.06 mAhg −1 and coulombic efficiency of 99.36%, while at high rate capability of 1800 mAg −1 , the rate capacity stabilize at 650.1 mAhg −1 . It is believed that the composite with good rate capability and stability can be a competitive anode for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

High-performance electromagnetic wave absorption materials with strong absorption intensity, broad bandwidth, low density and thin thickness can be widely applied in the civil and military areas. In this paper, FeNi 3 nanoalloy decorated on 3D architecture composite of reduced graphene oxide/molybdenum disulfide (FeNi 3 @RGO/MoS 2 ) was prepared by two-step of hydrothermal reaction. RGO/MoS 2 composite was synthesized by a hydrothermal process and then FeNi 3 nanoalloy was decorated on the RGO/MoS 2 nanosheets via the second hydrothermal process. Electromagnetic wave absorption performances of FeNi 3 @RGO/MoS 2 composite with different filler loadings in paraffin matrix were investigated for the first time and it improves significantly with the increase of filler loading. The maximum absorption bandwidth is 4.72 GHz with the thickness of 2.0 mm and the corresponding reflection loss value is −30.39 dB when the filler loading of FeNi 3 @RGO/MoS 2 is 40%. The ternary composite possesses dielectric loss and magnetic loss in the testing frequency region, magnetic loss plays an important role in low-frequency region and dielectric loss occupies the main part in the high-frequency area. [ABSTRACT FROM AUTHOR]

Flower-like NiFe 2 O 4 decorated on 2D graphene nanosheets composite and spherical NiFe 2 O 4 decorated on 2D graphene nanosheets composite have been synthesized through an easy method including one-pot hydrothermal route and one-pot heat treatment, respectively. In the well-designed 3D dimensional system, 2D graphene nanosheets work as conductive matrix to support the flower-like NiFe 2 O 4 and spherical NiFe 2 O 4 . The structure integrates the advantage of graphene nanosheets to preserve the electrode activity and integrity, improving the electrochemical performance. Lithium storage properties of the two kind of composites are compared as anode materials. The results presented that flower-like NiFe 2 O 4 /graphene composite shows better electrochemical performance and cycling stability. The first discharge capacity is 2632.6 mA h/g at a high current density of 100 mA/g. After 50 cycles, the reversible capacity is 606.2 mA h/g and the coulomb efficiency reaches at 98.86%. With the excellent electrochemical properties, flower-like NiFe 2 O 4 decorated on 2D graphene nanosheets could be a kind of promising potential candidate anode materials for LIBs. This research offers possibility to improve the lithium ion storage capacity of transition metal oxides through advisablely controlling the architecture and composition of anode materials. [ABSTRACT FROM AUTHOR]

The novel sandwich structures of graphene@Fe 3 O 4 @PANI decorated with TiO 2 nanosheets were firstly successfully prepared by simple hydrothermal method and in situ polymerization. VSM results reveal that the nanocomposites have a superparamagnetic behavior. Structure and morphology were characterized by X-ray diffraction, transmission electron microscopy, and field-emission scanning electron microscopy. Electron microscopy images show that TiO 2 nanosheets are mostly grown upright on the top of graphene@Fe 3 O 4 @PANI support with a random orientation, and form hierarchical structures. Electromagnetic (EM) wave absorption properties of graphene@Fe 3 O 4 @PANI@TiO 2 nanosheets containing 50wt% paraffin were investigated in the frequency region of 2–18 GHz. The maximum reflection loss of the nanocomposites is up to −41.8 dB at 14.4 GHz with a thickness of 1.6 mm, and the absorption bandwidth of R L < −10 dB is almost up to 3.5 GHz. Thus, the enhanced EM wave absorption properties of graphene@Fe 3 O 4 @PANI@TiO 2 nanosheets can be used as promising EM wave absorbers. [ABSTRACT FROM AUTHOR]

We report the characteristics of reflectance spectra of the 15- and 20-period ZnTe/ZnSe distributed Bragg reflector grown on GaAs (001) substrates by molecular beam epitaxy. The reflectance spectra measured at various incident angles and polarizations were investigated by the theoretical curves simulated using transfer matrix method. The wavelength variation of the refractive indices described by Sellmeier equation and random thickness model were also considered for the interpretation of the experimentally observed curves. An omnidirectional reflection range defined from the edge of incident-angle-dependent reflection band with TE and TM polarizations is about 15 nm, and is consistent with the observed experimental curves. The results showed that the selected ZnTe and ZnSe materials are suitable for constructing multilayer structures having omnidirectional reflection band. [ABSTRACT FROM AUTHOR]

The reduced graphene oxide (RGO)/cobalt ferrite (CoFe 2 O 4 ) composites with three different (RGO)/(CoFe 2 O 4 ) ratios were synthesized by a one-pot hydrothermal route. To research the influence of graphene reduction degree on electromagnetic parameters of graphene composites, RGO/CoFe 2 O 4 -2 was treated further by reduction process with different reducing agents (N 2 H 4 /NaBH 4 ). The crystalline structure, morphology, thermal stability, magnetic property of the synthesized samples were characterized by XRD, TEM, SEM, FT-IR, Raman, TG, VSM and XPS. The absorption properties of the RGO/CoFe 2 O 4 composites were studied. The maximum R L of RGO/CoFe 2 O 4 -2 composite is −47.9 dB at 12.4 GHz with a thickness of 2.3 mm, and the absorption bandwidth with the R L below −10 dB is up to 5.0 GHz (from 12.4 to 17.4 GHz) with a thickness of 2.0 mm. The results indicated that the RGO/CoFe 2 O 4 composites have remarkably electromagnetic performance, which are attributed to effective complementarities between the dielectric loss and the magnetic loss. Additionally, the microwave absorption properties of the RGO/CoFe 2 O 4 composites can be tuned easily by varying the (RGO)/(CoFe 2 O 4 ) ratio, the reduction degree of graphene and layer thickness of the samples. [ABSTRACT FROM AUTHOR]

The electromagnetic wave absorption properties of the ternary nanocomposites consisting of graphene, poly (3,4-ethylenedioxythiophene) and Fe 3 O 4 nanoparticles had never been reported. Herein, in order to expand the scope of electromagnetic wave absorption materials, the nanostructured graphene/poly (3,4-ethylenedioxythiophene) hybrid materials with Fe 3 O 4 nanoparticles had been synthesized by a controllable co-precipitation method. The nanocomposites were characterized by FTIR, XRD, TEM, Raman spectroscopy, XPS and TG analysis. The investigation of the electromagnetic parameters revealed that the excellent electromagnetic wave absorption properties of the nanocomposites may be attributed to the improved impedance matching, the enhanced interfacial effects and the geometric effect. The maximum reflection loss of the nanocomposites was up to −56.5 dB at 8.9 GHz and the absorption bandwidths exceeding −10 dB were 3 GHz with a thickness of 2.9 mm. Furthermore, our development strategies expanded the scope of the electromagnetic wave absorption materials and confirmed that the modification of graphene with poly (3,4-ethylenedioxythiophene) and Fe 3 O 4 nanoparticles makes the nanocomposites have a promising future in electromagnetic wave absorption materials. [ABSTRACT FROM AUTHOR]

Highlights: [•] The ternary nanocomposites of GN–PANI–Fe3O4 were synthesized via a two-step method. [•] The size of Fe3O4 nanoparticles on GN–PANI is in the range of 5–20nm. [•] The maximum RL of GN–PANI–Fe3O4 is −43.9dB at 11.4GHz with a thickness of 2.5mm. [•] All the maximum RL was less than −24.2dB when the thicknesses vary from 2 to 4mm. [•] The bandwidths exceeding −10dB are 11.0GHz when the thicknesses in 2–4mm. [ABSTRACT FROM AUTHOR]

Highlights: [•] PPy-RGO-Co3O4 nanocomposites were firstly synthesized by a three-step method. [•] The size of Co3O4 nanoparticles is in the range of 10-30nm. [•] The maximum RL of PPy-RGO-Co3O4 is −33.5dB at 15.8GHz at a thickness of 2.5mm. [•] The absorption bandwidth of PPy-RGO-Co3O4 with RL below −10dB is up to 11.4GHz. [Copyright &y& Elsevier]

To obtain high performance composites for thermal management fields, we adopt a new route to prepare the graphite flakes (Gf)/aluminum (Al) composites via vacuum pressure infiltration process. In this study, aluminum nitride (AlN) particles were used as supporting particles to obtain infiltration pathways for the penetration of the molten Al matrix. Gf, starch, urea and AlN were mixed evenly in the mass ratio of 1: 0.035: 0.058: 0.3 and then sintered at 330 °C to prepare porous preforms. It was observed that these substances had excellent chemical compatibility using characterization equipment. The improvement of the thermal transfer and mechanical properties of the composites for silicon coating was also studied. When the volume fraction of graphite was about 54%, compared with the samples without coating, the samples with SiC coating displayed an excellent thermal conductivity (TC) of 467.8 W/m·K and a promising bending strength of 58.8 Mpa, which increased about 82.1 and 238.0%, respectively. The coefficient of thermal expansion (CTE) of composites also decreased about 23.3% from 2.19 × 10−5 K−1 to 1.68 × 10−5 K−1 from room temperature to 380 °C. • Pretreatment of graphite with concentrated sulfuric acid produced a smoother surface with fewer impurities. • Si@Gf was successfully prepared by salt bath plating, in which silicon was in the form of SiC and SiO2. AlN as supporting particles can be evenly distributed in the composites. • When the graphite volume fraction was 53.1%, and the silicon volume fraction was 5.93%, the TC of the composite was up to 467.8 W/mK, and there was a stable CTE of about 1.68 × 10-5 K-1 at 380 °C, and the bending strength was 58.8 Mpa. [ABSTRACT FROM AUTHOR]

Due to high theoretical specific capacity, energy density, and low-cost lithium-sulfur (Li-S) batteries became the most potential energy storage devices for the next generation. The harsh shuttling effect, poor electroconductibility of sulfur, and volume change affect the Li-S battery's practical application. Herein, the rational design of porous hollow carbon aerogel (PHCA) with an ultra-high specific surface area of 2054.5 m2 g−1 and outstanding adsorption ability is firstly fabricated to restrict the shuttling effect of lithium polysulfides (LiPSs) by using commercialized nano-CaCO 3 as a template. As a sulfur host, the S/PHCA cathode delivers initially discharge specific capacity of 992.7 mAh g−1 with an average Coulombic efficiency of 97.6%. After 200 cycles, it obtains the reversible specific capacities of 600.1 mAh g−1 for S/PHCA cathode at 0.1C (2.2 mg cm−2) corresponding to 60.45% of their initial discharge specific capacity. As a PHCA interlayer, the Li-S battery with the PHCA interlayer exhibits initially discharge specific capacity of 1267.7 mAh g−1 with an average Coulombic efficiency of 99.36% at 0.1C (3.2 mg cm−2) and maintains at 863.3 mAh g−1 with the discharge specific capacity retention rate of 69.2%. This is an effective strategy to improve the outstanding electrochemical performance which is beyond reported carbon materials, which is attributed to stronger adsorption of LiPSs by the micropore. This work provides a new direction for the modification of a sulfur host and interlayer and simultaneously reveals the relationship between the heteroatom distribution and LiPSs. • The porous hollow carbon aerogel with an ultra-high specific surface area as a sulfur host and interlayer to absorb LiPSs. • The abundant porous structure acts as a lubricant role between LiPSs and the heteroatom of the PHCA. • Li-S batteries with a lightweight PHCA interlayer exhibit the outstanding electrochemical performance. • The areal density of the PHCA interlayer is only 0.008 mg cm−2. [ABSTRACT FROM AUTHOR]

Uniform Ag and Si layers were successfully prepared on the surface of graphite films (GF) to improve thermal conductivity (TC) by physical vapor deposition method (PVD). The results demonstrate that the unique cubic crystal structure of Ag layer with different deposition time show good interface bonding and no carbide product of Ag/GF composites. Meanwhile, the dense Si coating contribute to the enhancement of the thermal diffusion ability. The Ag/GF composites with the deposition time of 2 h possess the best comprehensive property with the TC of 9.93 (W/m·K), which is approximately 73.30% higher than untreated GF. The TC of Si/GF composites reach the maximum TC of 11.12 W/(m·K) and increase about 101.81% due to the nano-Si layer comparing with untreated GF. Those composites with high performance make them promising thermal management laminated materials. • Designing of three-dimensional structure of nano-plating benefits the surface property of heat export and displays strong bonding force with matrix (graphite film). • The TC of Si/GF composite increase about 101.81% due to the nano-Si layer. The performance of Ag/GF composites show an increase of 73.30% in TC. • Application of the Ag/GF and Si/GF composites make it potentially as one of the most promising thermal management materials for the stability of equipment. [ABSTRACT FROM AUTHOR]

High volume fraction of carbon material reinforced aluminum matrix composites were developed by optimized vacuum gas pressure infiltration method, among which the reinforced materials are graphite flake and carbon fiber. To enhance the wettability between the reinforments and aluminum matrix, graphite flake was coated with a thin layer of copper by electroless plating and CF was doped with nitrogen, which proves to be effective and efficient. With the increase of reinforcements from 50 to 80 vol%, the flexural strength of the composites remains at practical level; the coefficients of thermal expansion decrease under the same temperature in direction parallel to basal planes of graphite flake; the thermal conductivity of the composites increase from 327 to 402 W/m K, adding up to relatively high comprehensive performances. • Nitrogen doped carbon fiber was first introduced into the ternary aluminum matrix composites. • An insight into the composites to have a better understanding of the inner structure. • The obtained composites have high comprehensive properties, making them competive in related fields. [ABSTRACT FROM AUTHOR]

The core-shell composite of FeCo alloy coated with amorphous carbon and mesoporous silica (mSiO 2 for short) has been successfully fabricated through liquid-phase reduction, hydrothermal reaction as well as high temperature calcination, forming nanoparticles around 400 nm in size. The alloy core provides strong magnetic loss and keeps stable under the protection of the shell, while the carbon shell reduces density and promotes dielectric loss. The outer layer of mSiO 2 provides a larger specific surface area for multiple reflections, and meanwhile effectively adjusting the impedance matching, resulting in a better absorption. With a thickness of 3.5 mm, the maximum R L of the composite reaches −46.79 dB at 11.84 GHz, and the effective absorption bandwidth with the R L below −10 dB is up to 8.8 GHz (from 9.2 to 18.0 GHz). Hence, FeCo@C@mSiO 2 composite is potential to become an excellent candidate in the field of microwave absorption. • The iron-cobalt is well covered by amorphous carbon and mesoporous silica. • The reflection loss reaches −46.79 dB at 11.84 GHz with a thickness of 3.5 mm. • The composite shows a broad effective absorption bandwidth of 8.8 GHz. [ABSTRACT FROM AUTHOR]

SnS is an ideal material for supercapacitors because of its unique layered structure and excellent electrochemical performance, but the research of SnS based electrode materials of flexible self-supporting supercapacitors has been rarely exploited. In this study, microsphere like Co doped SnS grown on carbon nanofibers (Co-SnS@CNF) was prepared by electrospinning, hydrothermal method and annealing treatment. Co-SnS@CNF has great flexibility, high specific capacitance, excellent rate performance and cycle stability. Specifically, the specific capacitance is 750 F g−1 at the current density of 1 A g−1. The special microsphere structure with more electrochemical active sites and lower resistance of ion and charge transfer by Co doping are responsible for the superior electrochemical performances. Furthermore, when assembled Co-SnS@CNF as the symmetrical supercapacitor device, the energy density of 20.89 Wh Kg−1 and the power density of 376 W Kg−1 are achieved at the current density of 1 A g−1, while showing ultra-high cycle stability. Therefore, the Co-SnS@CNF offers excellent application potential for flexible self-supporting supercapacitors. • Revealing reasons for the high-performance of the microspherical Co-doped SnS. • The specific capacitance is 750 F g−1 at the current density of 1 A g−1. • The assembled symmetrical device exhibits the ultra-high cycle stability. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) with a honeycomb arrangement were designed onto graphene as the electrochemical electrodes. The honeycomb arrangement provided a relatively larger surface area to store more ions with a stronger structure to maintain long-term surface morphology. The combination of CNTs and graphene exhibited robust durability during electrochemical performance. The pseudo-capacitive property of IrO 2 was coated onto the CNT surface to enhance the capacitance. Cyclic voltammetry and charging–discharging measurements were used to examine the electrochemical behaviors. The CNTs/graphene and IrO 2 /CNTs/graphene capacitances were 3.93 and 129.40 F/g, respectively. The designed electrode demonstrates excellent characteristics and is appropriate for electrochemical applications. [ABSTRACT FROM AUTHOR]

Metal oxides are considered as promising anodes for alkali-ion batteries due to their high theoretical capacity and moderate volume expansion. However, they still suffer from the low electrical conductivity and capacity decay, resulting poor rate capability and cyclic stability. In this work, core-shell ZnO polyhedrons coated by Co nanoparticle embedded in N-doped carbon (ZnO@Co/NC) were prepared via a convenient route using zeolitic imidazolate frameworks as precursors. The unique structural design not only synergistically forms a three-dimensional conductive network to promote the transfer and storage of Li+/K+ ions, but also restrains the volume changes of ZnO polyhedron during repeated lithiation/potassiation processes, contributing to enhanced lithium and potassium storage performances. The ZnO@Co/NC anode delivers 458.3 mAh g−1 after 1000 cycles at an ultrahigh current density of 10 A g−1 with a capacity retention of 95% for LIBs, and remains 181.5 mAh g−1 after 1000 cycles at 200 mA g−1 with 84% retention for KIBs. When coupled with commercial LiFePO 4 cathode, the full cell delivers a capacity of 140.6 mAh g−1 after 250 cycles at 1 A g−1. This work not only shows the promising potential ZnO-based materials for long-term and high-rate lithium-ion batteries, but also gives an insight into the design of ZnO-based anodes for potassium storage. [Display omitted] • The Co-containing N-doped carbon layer provides three-dimensional networks to accelerate the transfer of ions and electrons. • The shell restrains the volume expansion of ZnO and modified the interfacial properties between anode and electrolyte. • The optimized anodes exhibit excellent cyclic stability and rate capability both in both lithium and potassium storage. • The potassium storage behaviors of ZnO-based electrode is revealed and analyzed in detail. [ABSTRACT FROM AUTHOR]

Amorphous carbon nitride (ACN) is a promising semiconductor photocatalyst for photocatalytic H 2 O 2 production. However, its actual activity is hindered by a high recombination rate of photoexcited charge carriers. Herein we report a K-doped ACN (K-ACN) photocatalyst synthesized via Ar plasma treatment to the modified melamine and KCl powder mixture at a moderate temperature. The as-synthesized K-ACN exhibits significantly enhanced photocatalytic properties for H 2 O 2 production with a yield of 6.21 mM h−1, which is 6 times higher than that of bulk CN. Moreover, the H 2 O 2 yield can be further increased to 13.95 mM h−1 by adjusting the pH value. The significantly enhanced photocatalytic property is mainly attributed to the introduction of K+, which is conducive to tuning the electronic structure, extending π conjugated system, passivating trap states and enhancing photocatalytic activity. The result has provided a facile and effective strategy for the modification of ACN to significantly boost its photocatalytic activity. [Display omitted] • K-ACN photocatalyst was synthesized via Ar plasma treatment to the modified melamine and KCl powder mixture. • The as-synthesized K-ACN exhibits 6-fold photocatalytic H 2 O 2 production relative to pristine carbon nitride. • The passivated trap states were observed in K-ACN and result in faster transport of light-induced active electrons. • K doping is conducive to tuning the electronic structure and enhanceing photocatalytic activity of ACN. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS 2 ) films are currently the most potential semiconductor materials of the two-dimensional nano-material heterojunction. Few-layer MoS 2 is an n-type semiconductor that has good mechanical strength, high carrier mobility, and has similar thickness as graphene. Graphene is presently the thinnest two-dimensional material with good thermal conductivity and high carrier mobility. The graphene Fermi level can be precisely controlled using the oxygen adsorption. Therefore, graphene can be tuned from zero-gap to p-type semiconductor material using the amount of adsorbed oxygen. In this study we combine few-layer MoS 2 and graphene to produce a heterojunction and exhaustively study the interface properties for heterojunction diode application. According to the results, the MoS 2 band-gap increases with decreasing thickness. The I–V characteristics of the MoS 2 /Graphene p-n junction diodes can be precisely tuned by adjusting different thicknesses of the MoS 2 films. By applying our fabricating method, MoS 2 /Graphene heterojunction diode can be easily constructed and have potential to different applications. [ABSTRACT FROM AUTHOR]

In filled CoSb 3 thin films with various In content were prepared on flexible substrates by multi-step co-sputtering method, which provided a promising way to prepare low-cost and high performance thin films. The influence of In content on the microstructure and thermoelectric properties of the CoSb 3 based thin films are systematically investigated. The thin film transforms from P -type to N -type with the increasing of In content. Both of the electrical conductivity and the Seebeck coefficient of the thin films increase after In filled. The thermal conductivity of the In filled thin film significantly decreases and the ZT value of the In-filled thin films are much higher than that of the unfilled thin film. It can be observed that the In filled thin films are single CoSb 3 phase and the grain size increases after In filled. The average grain size of all the thin films are less than 50 nm, indicates the thin films are nano-particles structure. [ABSTRACT FROM AUTHOR]

The g-C 3 N 4 (CN) microrods with superficial C, N dual vacancies were synthesized by facial thermal polymerization of melamine--cyanuric acid supramolecular (MCS) precursors under H 2 flow. Compared with bulk g-C 3 N 4 (BCN), the as-synthesized defective CN microrods with an increased specific surface area exhibit an enhanced photocatalytic performance with a kinetic constant (K) of ~0.19 min−1 for RhB degradation and an ~718.36 µmol g−1h−1 for H 2 O 2 production rate, which are about~17-fold and ~3-fold higher than that of BCN, respectively. The C, N dual vacancies are very effective in reducing the bandgap and inhibiting carrier recombination. The pivotal active species in RhB degradation is determined to be·O 2 -, and the pathway of H 2 O 2 production is confirmed as a sequential two-step single-electron reduction. The results have provided a great potential way to promote the practical application of CN for photocatalytic organic pollutant removal and H 2 O 2 production. The as-prepared g-C 3 N 4 microrods with superficial C, N dual vacancies exhibits enlarged specific surface area, improved photogenerated carriers separation efficiency, and enhanced photocatalytic performance for RhB degradation and H 2 O 2 production. [Display omitted] • The CN microrods with superficial C, N dual vacancies were synthesized by a facile thermal polymerization of MCS precursors under H 2 flowing. • Compared with BCN, the defective CN microrods exhibit significantly enhanced photocatalytic performance and high H 2 O 2 production rate. • The pathway of H 2 O 2 production is confirmed as a sequential two-step single-electron reduction. • The significantly enhanced photocatalytic performance is attributed to the synergistic effect of superficial C, N dual vacancies and morphology. [ABSTRACT FROM AUTHOR]

Abstract: The high quality La x Ce1− x B6 (x =0, 0.2, 0.4, 0.6, 1) single crystals with large emission current density have been successfully grown by floating zone method. The crystal structure, crystal quality and emission properties of La x Ce1−xB6 single crystals were characterized by 360° Phi scanning single crystal diffractometer, X-ray Laue diffraction and the thermal electron emission measurements. It is found that the as-grown crystals have a good crystal quality without subgrains and twin crystal phenomenon. The thermionic emission measurement results show that the maximum emission current density on (100) surface of La0.2Ce0.8B6 single crystal is 71.2A/cm2 at 1873K under an applied voltage of 800V, which is larger than the reported values in the literatures up to now. Furthermore, the crystals with different components also show a higher emission current density such as 53.8A/cm2 for La0.4Ce0.6B6 and 53.3A/cm2 for CeB6 single crystals. The field emission single tip made by LaB6 single crystal shows a superior performance than the polycrystalline LaB6 field emission tip and its field enhancement factor (β) is 36,231cm−1. Thus, the La x Ce1− x B6 single crystals will have promising application prospects as a hot or cold cathode. [Copyright &y& Elsevier]

Abstract: Three-dimensional flowerlike YBO3:Tb3+ phosphors have been successfully prepared by an efficient surfactant-free hydrothermal process directly without further sintering treatment. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDS) spectrometry, selected area electron diffraction (SAED), photoluminescence (PL) spectra were used to characterize the samples. The as-obtained samples present flowerlike agglomerates composed of nanoflakes with thickness of 20nm and high crystallinity in spite of the moderate reaction temperature of 180°C. The reaction mechanism has been considered as a dissolution/precipitation mechanism; the self-assembly evolution process has been proposed on homocentric layer-by-layer growth style. The different luminescent intensity with different molar ratio of Y–Tb [Y:Tb=8:2; 7:3; 6:4; 5:5; 4:6], YBO3:Tb3+ phosphors exhibit different light (white, red, green) under ultraviolet excitation, which might find potential applications in the fields such as light display systems and optoelectronic devices. [Copyright &y& Elsevier]

Abstract: Optical anisotropy of the below and above band-edge transitions in three samples of well-aligned and tilted ZnO nanorods has been characterized using thermoreflectance (TR) and photoluminescence (PL) measurements in the temperature range between 30 and 300K. The TR and PL spectra of the well-aligned nanorods with the largely top planes of {0001} show considerable difference in energy with respect to those of the other tilted nanorods with the largely side planes of . Optical-axial anisotropy of the defects and band-edge excitonic transitions in the well-aligned and tilted ZnO nanorods are observed. Temperature dependences of transition energies of the defect emissions and band-edge excitons for the ZnO are analyzed. The crystallinity for the as-deposited ZnO thin films is also discussed. [Copyright &y& Elsevier]

In order to construct tighter heterostructures, a novel Z-scheme β-Bi 2 O 3 /g-C 3 N 4 composite (xBC) was synthesized by in-situ growth method. The crystal phase, morphology, chemical composition, optical and photoelectrochemical properties of the composites were investigated by XRD, FT-IR, SEM, TEM, XPS, UV–vis DRS, EIS, etc. The characterizations verified that β-Bi 2 O 3 nanosheets grew uniformly on the surface of g-C 3 N 4. Meanwhile, the photocatalytic performance of xBC composites were also evaluated by degrading Rhodamine B (RhB) and p -Nitrophenol (PNP) under visible-light irradiation. As a result, 0.5BC exhibited the most superior performance, the removal efficiencies reached 71.6% for PNP in 300min and 94.8% for RhB in 120 min, with a rate constant (0.0233min−1) of 7.1 and 5.8 times than that of g-C 3 N 4 and β-Bi 2 O 3 , respectively. Evidences that Z-scheme carries transfer path were strongly confirmed by XPS, PL and reactive species analysis. Herein, we synthesized a novel direct Z-scheme β-Bi 2 O 3 /g-C 3 N 4 heterostructure by in-situ growth method. Image 1 • An in-situ growth method was proposed to synthesize g-C 3 N 4 /β-Bi 2 O 3 heterojunction. • The growth process of β-Bi 2 O 3 on the surface of g-C 3 N 4 was illustrated in detail. • The Z-scheme charge transfer pathway was proved by various characterizations. • The optimum mass ratio of β-Bi 2 O 3 to g-C 3 N 4 was 0.5 for RhB and PNP degradation. [ABSTRACT FROM AUTHOR]