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[Display omitted] Constructing an anode with fast electron transport and high cycling stability is important but challenging for large-scale applications of sodium-ion batteries (SIB). In this study, hierarchical flower-like MXene structures were synthesized using poly (methyl methacrylate) (PMMA) microsphere as templates. Subsequently, a straightforward hydrothermal reaction was utilized to anchor small-sized MoS 2 nanosheets. The resulting MXene@MoS 2 heterostructure exhibits a distinctive three-dimensional (3D) porous hollow architecture. This structure effectively addresses challenges related to self-aggregation of MoS 2 nanosheets and volume expansion of the electrode material during Na+ insertion/extraction processes. Furthermore, the robust hetero-interface supports fast and stable electron transfer, thereby enhancing electrochemical reaction kinetics. The prepared MXene@MoS 2 electrode demonstrates the specific capacity of 682.1 mA h g−1 at 0.2 A/g and the reversible capacity of 494.4 mA h g−1 after 1000 cycles at 5 A/g. It is noteworthy that the full battery assembled with the composite material as the anode can still maintain the capacity of 456.2 mA h g−1 after 80 cycles at 0.5 A/g. This outstanding reversible capacity and sustained stability over numerous cycles highlights its potential for a wide range of applications. [ABSTRACT FROM AUTHOR]

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]

As a substitute for graphene-based carbon materials, carbon fiber (CF) based absorbing materials have enormous application prospects. Effective improvements have been made in solving the problems of heavy quality and complex preparation processes of ordinary absorbing materials. In order to obtain a flexible thin fiber membrane absorbing material with good stability and excellent performance, we prepared a multi-layer hollow carbon sphere/CF@MoSe 2 with carbon fiber as the matrix, and controlled the microstructure through hollow carbon shell and MoSe 2 , and introduced transition metal chalcogenides to coordinate electromagnetic parameters. As a result, the hollow carbon sphere/CF@MoSe 2 flexible composite film achieved a minimum reflection loss (RL min) of −47.98 dB at a thickness of 2.5 mm, and an effective bandwidth (EAB) of 8.1 GHz at a thickness of 2.7 mm. The RL min of the hollow carbon ball/CF composite film reached −45 dB at a thickness of 2.6 mm, and the EAB reached 3.2 GHz. The theoretical characterization results jointly prove the reason for the improved performance, and this study provides an experimental basis for a more in-depth exploration of the birth of new absorbing materials. [Display omitted] • Elucidated the growth mechanism of electromagnetic wave absorption in multi-layer core-shell heterostructures. • The prepared hollow carbon shell/CF@MoSe 2 achieved an effective absorption bandwidth of 8.1 GHz. • Hollow carbon shell/CF@ MoSe 2 achieves effective absorption in the X and Ku bands. [ABSTRACT FROM AUTHOR]

With the development of electronic communication technology, the issues of electromagnetic (EM) wave pollution have become increasingly prominent, and the requirements for EM wave absorbing materials are rising. Polypyrrole (PPy), an important type of conductive polymers, has attracted increasing attention in the applications of EM wave absorbing due to their facile synthesis process, low density, good conductivity, corrosion resistance, and stable chemical properties. Various PPy-based composite materials exhibit excellent electromagnetic absorbing properties and have been widely reported in the literature. In this review, the recent development and understanding of PPy and PPy-based composites materials in the applications of EM wave absorption are summarized in detail. In particular, as a conductive loss-type absorbing material, we focus on the design and fabrication of PPy-based composites and explore the significant impact of EM parameters on the EM wave absorbing properties. Finally, perspectives are provided for future directions of advanced PPy and PPy-based composites for microwave absorbers. [ABSTRACT FROM AUTHOR]

A simple preparation method of the anode is designed for sodium ion battery. The bimetallic selenide (CoSe 2 /ZnSe) and nitrogen-doped carbon composite materials are obtained by selenization and carbonization of the metal organic framework precursors, and applied to high-performance sodium ion storage. The ingenious nanostructure is shown in that CoSe 2 and ZnSe nanoparticles are evenly distributed on the fusiform flake carbon skeleton. This synergy can improve the capacity and conductivity, and inhibit the volume expansion during the cycle. For electrochemical performance analysis, the prepared 1:1-CoSe 2 /ZnSe@NCC electrode shows a high discharge specific capacity of 621.5 mA h g-1 at 0.1 A g-1 after 100 cycles (coulomb efficiency close to 100%, capacity retention reaches ~ 90%), and has advantages over other electrodes in terms of rate performance and reaction kinetics. The excellent electrochemical performance confirms the successful development of a high performance electrode for sodium ion storage by this strategy. [ABSTRACT FROM AUTHOR]

An online control by the magnetic method is considered as a nondestructive evaluation approach to detect the variation of the microstructure. The magnetic model used for each phase is based on a magneto-mechanical coupling model, which is characterized, on the one hand, by the influence of applied field on the magnetic susceptibility and magnetostriction; on the other hand, it is characterized by the effect of mechanical stress on magnetization of a material. In order to predict the macroscopic behavior correctly, this model takes not only account for the multiphased state of dual-phase steels for each phase separately but also for the heterogeneity of stress and magnetic field through a self-consistent localization-homogenization scheme. The proposed multiscale approach is based on the hypothesis of domain energy balance, including the localization step, the local constitutive law application, evaluation of the volumetric fraction of martensite, and the homogenization step. Results are discussed and compared with experimental data from the literature. [ABSTRACT FROM AUTHOR]

Hollow and porous three-dimensional Co(Ni)Se 2 /N-doped carbon composite particles prepared by a simple process using metal organic framework (MOF) precursors as the template are used as a high-efficiency anode material for sodium ion batteries. The composite material having a regular rhombohedral dodecahedral structure contains the N-doped porous carbon shell and the nano-metal selenide (CoSe 2 and NiSe 2) embedded in the carbon shell. Moreover, the metal selenide has a high capacity density, and the N-doped porous carbon structure can enhance the electrical conductivity and structural stability of the material to suppress volume expansion. Their effective synergistic combination shows excellent electrochemical performance. As the anode of the sodium ion battery, Co(Ni)Se 2 @NCC exhibits a very high specific capacity of up to 735.2 mA h g−1 after 100 cycles and superior rate performance. In addition to these, excellent kinetic performance and cycle stability and coulombic efficiency are sufficient to prove that this material has broad prospects in sodium-ion battery anodes. [ABSTRACT FROM AUTHOR]

High-performance lithium-ion batteries (LIBs) and sodium-ion battery (SIBs) anode materials Co 3 S 4 –ZnS/NC are prepared by carbonization and subsequent sulfidation using Co, Zn-based zeolitic imidazolate frameworks (ZIF) as a precursor. ZnS and Co 3 S 4 in-situ doping on polyhedral carbon framework, which enhances the conductivity and can buffer the volume expansion during the cycle and improve the kinetics. When Co 3 S 4 –ZnS/NC use as an anode material for LIBs, which can deliver reversible capacity 750 mA h g−1 after 200 cycles at current density of 1 A g−1. It also exhibits excellent sodium storage, with capacities remaining 316.5 mA h g−1, after 1000 cycles at current density of 1 A g−1. Compared with pure ZnS/NC and Co 3 S 4 /NC electrode, the Co 3 S 4 –ZnS/NC electrode also exhibits enhanced rate performance in both Li/Na storage. This excellent performance may be due to the following factors. (a) The polyhedral carbon skeleton makes the composites has superior conductivity and excellent structural stability. (b) The large specific surface area and porous structure can make the electrolyte fully infiltrate the electrode. (c) The high capacitance contribution gives the composite excellent Li/Na storage performance, especially at high current density. These results reveal the potential application prospects of Co 3 S 4 –ZnS/NC in high performance LIBs and SIBs. Schematic illustration of detailed synthesis of three composites material. Firstly, the ZIF polyhedral precursor was prepared by simple liquid phase diffusion method. Then the precursor was carbonized at 600 °C for 2 h under the protection of argon gas. Finally, the subsequent sulfidation process was completed under hydrothermal conditions with TAA, and finally three composites material was obtained. Image 1 [ABSTRACT FROM AUTHOR]

The FeCo@SiO2/holey reduced graphene oxide composite was successfully prepared by combining liquid-phase reduction reaction in argon atmosphere with high-temperature calcination. The FeCo@SiO2/holey reduced graphene oxide composite was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, vibrating sample magnetometer, Fourier transform infrared spectroscopy, Raman spectroscopy, transmission electron microscopy and scanning electron microscopy analysis and exhibit excellent electromagnetic wave absorption properties. The maximum reflection loss of FeCo@SiO2/holey reduced graphene oxide composite reaches –46.28 dB at 16.16 GHz with the thickness of 1.5 mm and the absorption bandwidth with the reflection loss below –10 dB was up to 3.92 GHz (from 14.08 GHz to 18 GHz) with the thickness of 1.5 mm. The absorption bandwidth with RL below –10 dB is up to 12.64 GHz. It is believed that the FeCo@SiO2/holey reduced graphene oxide composite can serve as an excellent microwave absorber. [ABSTRACT FROM AUTHOR]

Highlights • The NiCo 2 O 4 and NiCo 2 O 4 @MnO 2 composites synthesized by a hydrothermal method. • NiCo 2 O 4 @MnO 2 maintained reversible capacities of 1000 mA h g−1 after 100 cycles. • NiCo 2 O 4 @MnO 2 electrodes demonstrated an enhanced rate performance. Abstract 3D flower-like NiCo 2 O 4 and NiCo 2 O 4 @MnO 2 were successfully synthesized via a hydrothermal method. Scanning electron microscopy results illustrated that NiCo 2 O 4 is formed by stacking nanosheets, and after reaction in KMnO 4 solution, MnO 2 were evenly coated on the surface of NiCo 2 O 4 formed flower-like structure. The as-synthesized materials were evaluated as an anode materials for lithium-ion batteries, NiCo 2 O 4 and NiCo 2 O 4 @MnO 2 exhibited high specific capacities of 841.9 and 1 000 mA h g−1 after 100 cycles respectively. Moreover, NiCo 2 O 4 @MnO 2 composites demonstrate good rate performance. These enhanced electrochemical properties could be attributed to the distinctive 3D flower-like structure, which increases the contact area between the electrolyte and electrode material to provide more active sites, and reduced volume effects during repeated insertion/extraction of lithium ions. The results suggest that the NiCo 2 O 4 @MnO 2 composites could be promising LIBs anode materials. [ABSTRACT FROM AUTHOR]

Graphical abstract Synthesis and microwave absorption properties schematic diagram. Abstract A novel hierarchical composites for coupling thistle-like CoNi with dielectric Ag decorated graphene in paraffin wax as high performance microwave absorber has been synthesized by a facile two-step strategy. The components, particle size, microstructure and morphology of the resulting composites are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectra, scanning electron microscope, transmission electron microscopy and energy dispersive X-ray spectroscopy, etc. Due to the unique flower structure and good synergistic effect of dielectric loss and magnetic loss, thistle-like CoNi@dielectric Ag decorated graphene composites have showed glorious microwave absorption intensity and frequency width. The maximum reflection loss of −61.9 dB can be gained at 6.96 GHz, which has rarely been reported yet. In addition, the corresponding effective bandwidth with reflection loss less than −10 dB is 5.6 GHz ranging from 12.4 to 18 GHz at only 1.67 mm thickness. This highly efficient and broad band features endow thistle-like CoNi@dielectric Ag decorated graphene composites with promising applications in microwave absorption, electromagnetic shielding, information safety, direct broadcast satellite and military radar fields. [ABSTRACT FROM AUTHOR]

Abstract In this work, an eco-friendly and convenient microwave-assisted synthesis technique was applied in the entire experiment course. The first obtained graphene-Ni composite possess an unsatisfactory microwave absorption capacity due to unbalanced matching nature. Then a sulfurization process was tried at different temperatures to convert Ni into NiS/Ni 3 S 2 , and an innovative graphene-NiS/Ni 3 S 2 composite with a hierarchical architecture was fabricated under the condition of microwave irradiation. The investigation into microwave absorbing performances manifests that the absorption property of graphene-Ni can be obviously improved by sulfurization method. The results show, compared with graphene-Ni, the hierarchical-architecture graphene-NiS/Ni 3 S 2 composites generated at 150 ℃ (S-150) possess excellent absorbing ability with a maximum RL as strong as − 55.1 dB at 6.0 GHz with a thickness of 2.7 mm, and the effective bandwidth covers 8.6 GHz from 2.8 to 11.4 GHz with thickness varies in 1.5–4.5 mm range. The enhanced performances for S-150 mainly derive from the synergy of superior impedance matching character, high attenuation, dielectric loss and plenteous interface polarizations. [ABSTRACT FROM AUTHOR]

A free-standing Si@Co 9 S 8 CF electrode with excellent rate capability and cycling performance was obtained by electrospinning, vulcanization, and carbonization processes as high-performance anode for Li-ion batteries. [Display omitted] • Si@Co 9 S 8 CF films are explored by electrospinning, vulcanization and carbonization. • The yolk-shelled Si@Co 9 S 8 can remarkably alleviate the volume expansion. • The introduction of CFs can improve the electrical conductivity of the electrodes. • The free-standing anode avoids the conventional process of electrode preparation. Silicon-based (Si-based) materials have aroused extensive attention owing to their ultra-high theoretical specific capacity, while the huge volume expansion and inferior electronic conductivity have impeded their practical application in lithium-ion batteries (LIBs). Rational structural design has been regarded as a fascinating strategy, especially for yolk-shell structures. Herein, Si nanoparticles (Si NPs) were encapsulated in ZIF-67 metal–organic frameworks to obtain Si@ZIF-67 particles, which were wrapped in one-dimensional carbon fibers (CFs) by simple processes of electrospinning, vulcanization and carbonization to obtain a free-standing Si@Co 9 S 8 CF electrode. The yolk-shelled Si@Co 9 S 8 particles could remarkably ameliorate the volume variation of Si materials during the lithiation/de-lithiation cycling and the introduction of CFs endowed an efficient one-dimensional electronic pathway accurately to improve the conductivity of composite materials. In addition, it was not negligible that the as-obtained Si@Co 9 S 8 CF films could be as a self-supporting electrode, which avoided the traditional cumbersome procedure of the electrode preparation. The resulting composite electrodes possess an excellent rate performance and an ultra-stable cycling lifespan. We hope this work can provide some novel insights for the development of the self-supporting Si-based electrode materials. [ABSTRACT FROM AUTHOR]

Novel a - MoO 3 nanorods coated with SnS 2 nanosheets core-shell nanorod composite has been synthesized via two hydrothermal routes. More importantly, as the anode materials for lithium ion batteries, the MoO 3 @SnS 2 core-shell nanorod composite has not been investigated in detail. The one-dimensional core-shell nanorod composite has high surface area, which could offer larger contact area for material and electrolyte. In addition, there are large enough inner spaces between the SnS 2 nanosheets, which provides an efficient transport of electrons and ions. In addition, the core-shell nanostructure could accommodate the volume changes caused by the charge/discharge reaction and could avoid the agglomerations and pulverization of anode materials.As anode materials for LIBs, the as-prepared MoO 3 @SnS 2 core-shell nanorod composite displayed 1663.2mAh/g discharge capacity in the first cycle at the current of 60mA/g. After 100 cycles, the remained capacity is 568.2mAh/g, which is both higher than that of a-MoO 3 and SnS 2 . Considering the excellent electrochemical performance with high capacity and good cycling stability, the as-prepared the MoO 3 @SnS 2 core-shell nanorod composite has the potential to be the next generation anode materials for lithium ion batteries. [ABSTRACT FROM AUTHOR]

The surface of magnetic powders with diameter size of 10–20 μm was modified by SiO 2 . The appearance, structure and phase constitution of the powders before and after treatment were characterized by SEM, XRD. The electromagnetic and microwave absorbing properties of the obtained samples were measured by AV3629D network analyzer in the frequency ranges of 8.2–12.4 GHz. The band width below −10 dB for Fe(CO) 5 /SiO 2 nanocomposites absorber is far larger than that of Fe(CO) 5 absorber. The SiO 2 layer has an effect on the microwave absorbing properties of the composites. Fe(CO) 5 /SiO 2 nanocomposites absorber is a broadband absorption, high temperature resistant absorber in X band. [ABSTRACT FROM AUTHOR]

Porous SnO 2 /NiO/graphene ternary composites had been synthesized. Used as anode materials for lithium ion batteries, graphene supported porous SnO 2 /NiO ternary composites demonstrate excellent electrochemical performance and cycling stability. The first discharge capacity is 1280.4 mAh/g at a high current density of 300 mA/g. After 50 cycles, the reversible capacity is 410.74 mAh/g and the coulomb efficiency reaches at 99.4%. [ABSTRACT FROM AUTHOR]

The electromagnetic wave absorption properties of the quaternary composites consisting of reduced graphene oxide (rGO), polyaniline (PANI), FeNi 3 @SiO 2 (FeNi 3 nanocrystals encapsulated in SiO 2 ) nanoparticles had never been reported. In this case, we prepared FeNi 3 @SiO 2 @rGO–PANI quaternary composites and TEM results shows spherical nanoparticles are well distributed on the surface of rGO–PANI nanosheets. The investigation of the electromagnetic wave absorbability reveals that the quaternary composites exhibit wide absorption bandwidth and enhanced electromagnetic wave absorption properties. The absorption bandwidth with reflection loss less than −10 dB (90% attenuation) is up to 6.64 GHz (10.08–10.80 GHz, 12.08–18.0 GHz), and the maximum reflection loss reaches about −40.18 dB at 14.0 GHz with the thickness of 2.4 mm. It is believed that the FeNi 3 @SiO 2 @rGO–PANI composites can serve as excellent electromagnetic wave absorbent and can be widely used in practice. [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]

Flower-like ZnO/CuO microstructures have been fabricated on Cu substrate via a simple hydrothermal method. The as-prepared ZnO/CuO flowers/graphene (GNS) composites had distributed the ZnO/CuO flowers on the graphene sheets. As anode materials for lithium ion batteries (LIBs), the ZnO/CuO flowers/GNS composites showed substantially higher reversible capacity and better cycling stability compared to ZnO/CuO flowers, which has been attributed to the improvement of structure stability and electrical contact by GNS. The method may be readily extended to synthesize other classes of hybrids based on graphene sheets for technological applications. [ABSTRACT FROM AUTHOR]

Hydriodic acid and self-assembly approach are used to fabricate graphene wrapped sulfur composite. The self-assembly process of the relative “large” graphene sheet and “small” sulfur is quite controllable, and the sulfur particles are completely enfolded by RGO sheets with a unique stacked structure .The RGO/S composite with 80 wt.% sulfur shows an initial discharge capacity of 865.1 mAh g −1 at 0.5 mA/cm 2 . A high specific capacity of 720 mAh g −1 with a coulombic efficiency of 95% is achieved after 50 cycles of charge/discharge. The material also delivered a capacity of more than 580 mAh g −1 at 2 mA/cm 2 and can be recovered to 736 mAh g −1 when the rate is returned to 0.2 mA/cm 2 , representing a promising cathode material for high current discharge lithium-sulfur batteries. [ABSTRACT FROM AUTHOR]

Two kinds of hierarchical structures of graphene@Fe 3 O 4 @C@PANI (polyaniline) nanorod arrays were prepared by covalently and noncovalently grafting PANI nanorod arrays to the surface of graphene@Fe 3 O 4 @C, respectively. The measured electromagnetic parameters show that the bonding form between PANI nanorod arrays and graphene@Fe 3 O 4 @C have significantly effect on microwave absorption properties of graphene@Fe 3 O 4 @C@PANI nanorod arrays hierarchical structures, and the formation of covalent bond between PANI nanorod arrays and graphene@Fe 3 O 4 @C in hierarchical structures exhibits significantly enhanced microwave absorption performance. The maximum reflection loss is up to −44.2 dB at 11.4 GHz and the absorption bandwidth with a reflection loss below −10 dB ranges from 9.7 to 15.5 GHz with a thickness of 3 mm. Therefore, the high microwave absorption performance with lightweight and wide absorption frequency band can be realized by fabricating graphene-based hierarchical structures using covalent bond interaction. [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]

Hollow Zn 2 SnO 4 boxes@C/graphene ternary composites with a three-dimensional triple buffering structure are prepared by two hydrothermal processes followed by a calcined process. The structure, morphology and electrochemical properties of the ternary composites were investigated by means of XRD, FTIR, Raman, BET, BJH, SEM, TEM, and electrochemical measurements. The hollow Zn 2 SnO 4 boxes are coated with carbon layer and then supported by graphene sheets to form a 3D carbon conductive network. Compared with the hollow Zn 2 SnO 4 boxes@graphene binary composites, the hollow Zn 2 SnO 4 boxes@C binary composites, the hollow Zn 2 SnO 4 boxes and the solid Zn 2 SnO 4 cubes, the hollow Zn 2 SnO 4 boxes@C/graphene ternary composites show an enhanced electrochemical performance (726.9 mAh g −1 at a current density of 300 mA g −1 after 50 cycles) and high rate capability. With the unique structure design, this kind of composites with excellent electrochemical properties can be a promising anode material for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: The microwave absorption properties of the presented ternary composites are not satisfactory and the microwave absorption properties of the ternary composites composed of graphene, polypyrrole and Fe3O4 have never been reported. Herein, in order to expand the scope of microwave absorbers, the graphene/polypyrrole/Fe3O4 (GN/PPy/Fe3O4) composites were synthesized by a co-precipitation method. The microwave absorbability reveals that GN/PPy/Fe3O4 exhibits excellent microwave absorption properties and broad absorption bandwidths compared with GN, GN/PPy and GN/Fe3O4. The maximum reflection loss of GN/PPy/Fe3O4 is up to −56.9dB at 6.6GHz with a thickness of 5.3mm and the absorption bandwidths exceeding −10dB are more than 15.1GHz with a thickness in the range of 3–7mm. Furthermore, our strategy confirms that GN/PPy/Fe3O4 can be used as an attractive candidate for the new type of microwave absorbers. [Copyright &y& Elsevier]

Abstract: Flower-like Zn2SnO4 composites had been prepared through a green hydrothermal synthesis. The structural, morphological and electrochemical properties were investigated by means of XRD, BET, SEM, TEM, and electrochemical measurement. The results show that the as-prepared sample is in high purity phase and of good crystallinity; meanwhile it has a particular 3-D structure and large surface area. Electrochemical measurement suggests that flower-like Zn2SnO4 composites exhibit better cycling properties and lower initial irreversible capacities than the solid Zn2SnO4 cubes. The first discharge and charge capacities of the material are 1750mAhg−1 and 880mAhg−1 respectively. A higher reversible capacity of 501mAhg−1 was obtained after 50 cycles at a current density of 300mAg−1. The higher reversible capacity and good stability can be related to the special nanostructural features of the material. Such Zn2SnO4 structures synthesized by the simple and cheap method are expected to have potential application in energy storage. [Copyright &y& Elsevier]

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]

The composites of reduced graphene oxide-polyaniline film (RGO-PANI) were synthesized by an in situ polymerization method and the microwave absorption properties of the composites were investigated. FESEM results indicate that RGO is covered with polyaniline film, and some PANI nanoparticles with the diameter in the range of 10-30 nm embed in the film. As PANI film covered on RGO, the microwave adsorption properties of RGO are significantly enhanced. The maximum reflection loss of RGO-PANI is up to −41.4 dB at 13.8 GHz and the bandwidths exceeding −10 and −20 dB are 4.2 GHz (from 11.7 to 15.9 GHz) and 1.5 GHz (from 12.8 to 14.3 GHz) with a coating layer thickness of 2 mm. The excellent microwave absorption properties of the composites may be attributed to the unique structural characteristics and the charge transfer between RGO and PANI film. Thus, the composites can be used as an attractive candidate for the new type of microwave absorption materials. [ABSTRACT FROM AUTHOR]

Bamboo charcoal/LiSnO composites for lithium-ion batteries were synthesized by a sol-gel route. The structure, morphology, and electrochemical properties of the composites were detected by means of X-ray diffraction, scanning electron microscope, Raman spectroscopy, thermal gravimetric analysis, and electrochemical measurements. The results showed that LiSnO particles were loaded on the surface of bamboo charcoal and some of them entered into the hole. The bamboo charcoal/LiSnO composites exhibited good electrochemical performance with high capacity and good cycling stability (616.5 mAh g after 50 cycles). The composites showed a better electrochemical property than LiSnO and bamboo charcoal. [ABSTRACT FROM AUTHOR]

Abstract: Composite Li2SnO3/C with good cycle performance for lithium-ion batteries was synthesized by a hydrothermal route. The structure, morphology and electrochemical properties of the as-prepared materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA) and electrochemical measurements. Results show that the length of the Li2SnO3 nanorods are in the range of 40–60nm while the average diameter is approximately 30nm. Amorphous carbons are distributed among the Li2SnO3 nanoparticles. The first discharge–charge capacities of Li2SnO3/C are 2045.8mAhg−1 and 1756.6mAhg−1. After the 50th cycles, the capacity retained is 598.3mAhg−1 at a constant current density of 60mAg−1 in the voltage range of 0.05–2.0V. The composite Li2SnO3/C exhibits a better electrochemical property than Li2SnO3. [Copyright &y& Elsevier]

Abstract: Strontium ferrite particles were firstly prepared by sol–gel method and self-propagating synthesis, and then the polyaniline/strontium ferrite/multiwalled carbon nanotubes composites were synthesized through in situ polymerization approach. Structure, morphology and properties of the composite were characterized by various instruments. XRD analysis shows that the output of PANI increases with the increase of the content of MWCNTs, due to the large surface area of MWCNTs. Because of the coating of PANI, the outer diameter of MWCNTs increases from 10nm to 20–40nm. The electrical conductivity of the composites increases with the amount increase of MWCNTs and reaches 7.2196S/cm in the presence of 2g MWCNTs. The coercive force of the composites prepared with 2g MWCNTs is 7457.17Oe, which is much bigger than that of SrFe12O19 particles 6145.6Oe, however, both the saturation magnetization and the remanent magnetization of the composite become much smaller than those of SrFe12O19 particles. The electromagnetic properties of the composite are excellent in the frequency range of 2–18GHz, which mainly depend on the dielectric loss in the range of 2–9GHz, and mainly on the magnetic loss in the range of 9–18GHz. [Copyright &y& Elsevier]

The ternary composite material ZnFe 2 O 4 @PANI-rGO with a core-shell structure and excellent electromagnetic absorption properties has been prepared by covalently modifying reducing graphene oxide with the binary magnetic material ZnFe 2 O 4 @PANI. The ternary composite material ZnFe 2 O 4 @PANI/rGO forms a " CO–NH ″ covalent bond between ZnFe 2 O 4 @PANI and rGO through hydrothermal routes and mechanical stirring. By comparing the two types of the connection method covalent and non-covalent bonds, it was surprised to find that formed by covalently connecting the binary ZnFe 2 O 4 @PANI material and rGO (C-ZPr) to obtain extremely excellent electromagnetic absorption performance. By adjusting the thickness from 1 mm to 4 mm, when the filler ratio is 20%, the minimum reflection loss (R Lmin) at 2.1 mm was as low as −49.99 dB at 17.28 GHz and the effective absorption bandwidth (R L < 10 dB) was almost 4.32 GHz. The introduction of covalent bonds becomes a bridge connecting magnetic materials and dielectric materials, adjusting electromagnetic parameters, enhancing reflection loss, and achieving impedance matching and improved electromagnetic absorbing performance. This preparation method is expected to provide new ideas for the preparation of high-performance absorbing materials in the future. [Display omitted] [ABSTRACT FROM AUTHOR]

The random packing of aggregate particles is an important factor affecting the mechanical properties of concrete at the mesoscopic scale. In the current study, a meso-mechanical pretreatment algorithm is developed to construct the random ellipsoidal aggregate model for the mesoscopic structure of fully graded concrete. The Fuller curve combined with equivalent diameter is adopted to ensure equality between the gradation and content of the random ellipsoidal aggregates and those of the actual geometric aggregates. A 'removing occupied space' method is proposed to improve the packing efficiency based on the background grids strategy. A modified search algorithm consisting of rough and fine detection for determining the overlaps is proposed to improve the optimised simulation of the meso-structure of cement-based composites. A random ellipsoidal aggregate model with different aspect ratios of ellipsoid is developed and compared with the existing algorithms to test the efficiency of the new pretreatment algorithm. The effect of the ellipsoidal shape on the random packing fraction is investigated based on the proposed pretreatment algorithm. The pretreatment algorithm proposed greatly improves the efficiency of packing and provides a powerful tool for the realisation of three-dimensional large-scale numerical meso-concrete. [ABSTRACT FROM AUTHOR]

A high-strength and water-soluble magnesium sulfate bonded sand core (WSMBS) material cured by twice microwave heating was successfully fabricated using magnesium sulfate aqueous solution as a binder, which is suitable for manufacturing hollow composite structures castings. The effects of various factors on the properties of WSMBS were investigated. The results shows that WSMBS possesses some advantages of good water solubility, high curing speed and strength. The tensile strength of WSMBS is more than 0.6 MPa under optimal parameters, and when the temperature of WSMBS ranges from 105 °C to 116 °C, the tensile strength is superior and MgSO 4 ·7H 2 O is dehydrated to MgSO 4 ·4H 2 O or MgSO 4 ·3H 2 O. The moisture absorbability of WSMBS is quite high, and it rises with increasing the stored time and the magnesium sulfate binder content. The scanning electron microscope analysis shows that there are some micro-cracks or holes in the bonding bridge that decreases the strength of WSMBS after being put in humidistat for several hours. The energy dispersive X-ray analysis shows that the bonding bridge mainly comprises magnesium sulfate and so the use of WSMBS in casting does not release toxic gases. The water-solubility rate of WSMBS is 57.9 kg·min −1 ·m −2 , which can be dissolved in water quickly after casting and overcome the poor leachability of the common bonded sand core, and therefore the used WSMBS can be easily reclaimed by water scrubbing method and the use of WSMBS can improve the production efficiency of the complex hollow composite castings with many interior channels or passages, undercuts. What is more, the aqueous solution of magnesium sulfate can be made from waste water which is used for dissolving the sand core after casting, and therefore it can realize green casting with no toxic gas during casting and recycling magnesium sulfate binder. [ABSTRACT FROM AUTHOR]

Tissue engineering approaches have been adapted to reconstruct and restore functionality of impaired tissue for decades. Porous biomimetic composite scaffolds of Chitosan (CH) with hydroxyapatite (HA) for bone regeneration have also been extensively studied in the past. These porous scaffolds play a critical role in providing successful regeneration by acting as a three-dimensional template for delivering nutrients and metabolites and the removal of waste by products. The aim of the current study was to investigate in- vitro and in- vivo degradation rates of porous freeze gelated chitosan (CH) and CH hydroxyapatite scaffolds by scanning electron microscopy (SEM) to observe for morphological changes, Fourier Transform Infrared Spectroscopy (FTIR) in conjunction with photo-acoustic sampling (PAS) accessory for the analysis of chemical changes, pH analysis and UV–Vis spectroscopy of degraded supernatant. SEM results showed significant alterations in the surface morphology. FTIR-PAS spectra showed changes in the finger print region and glycosidic bonds showed signs of breakage. pH values and UV–Vis spectroscopy of the degraded supernatant were indicative of CH bonds scission in neat samples. HA incorporated specimens showed more stability. Histological sections performed after in- vivo implantation also showed greater cellular infiltration and delayed degradation profiles by HA loaded samples. Within 30 days of implantation, neat CH scaffolds showed complete in- vivo biodegradation. The current findings show the advantage of adding hydroxyapatite to porous templates which enhances hard tissue regeneration. In addition, it allows easy and cost effective fabrication of bioactive composite scaffolds. [ABSTRACT FROM AUTHOR]

Hydrogel has attracted tremendous attentions due to its excellent biocompatibility and adaptability in biomedical field. However, it is challenging by the conflicts between inadequate mechanical properties and service requirements. Herein, a rapid and robust hydrogel was developed by interpenetrating networks between chitosan and silk fibroin macromolecules. Thanks to these unique networks, the chitosan-based hydrogel exhibited superior mechanical performances. The maximum breaking strength, Young's modulus and swelling ratio of the hydrogel were 1187.8 kPa, 383.1 MPa and 4.5 % respectively. The hydrogel also supported the proliferation of human umbilical vein endothelial cells for 7 days. Notably, the hydrogel was easily molded into bone screw, and demonstrated compressive strengths of 45.7 MPa, Young's modulus of 675.6 MPa, respectively. After 49-day biodegradation, the residual rate of the screw in collagenase I solution was up to 89.6 % of the initial weight. In vitro , the screws not only had high resistance to biodegradation, but also had outstanding biocompatibility of osteoblast. This study provided a promising physical-chemical double crosslinking strategy to build orthopedic materials, holding a great potential in biomedical devices. In order to enhance the stability of the composite hydrogels at mesoscale, chitosan was used as the base material to form interpenetrating networks with structural proteins. The CSMA/SF hydrogel was successfully prepared into reinforced bone screws. The screws exhibited superior biocompatibility, anti-biodegradability and mechanical properties. This study offered promising avenues for the rapid preparation of orthopedic devices. [Display omitted] • Interpenetrating CSMA/SF hydrogel was prepared by physical and photocrosslinking strategy. • CSMA/SF hydrogel was reinforced by these interpenetrating networks. • CSMA/SF hydrogel was easily process into the bone screw with high mechanical properties. • The CSMA/SF bone screw showed high anti-biodegradation and biocompatibility. [ABSTRACT FROM AUTHOR]

Thermal Spraying technologies are proven to be capable of producing composite materials and structures. In the present work, an innovative composite coating was produced to achieve high wear and thermal resistant properties in a single-step process using air plasma spraying ( APS) technique. Tungsten carbide has shown high wear resistance and zirconia coatings exhibited excellent tribological and insulation properties. It is speculated that a composite material consisting of zirconia and tungsten carbide exhibits excellent thermomechanical properties. A powder mixture of 50wt% WC-10wt% Ni ( WC-Ni) and 50wt% ZrO2-8wt% Y2O3 ( YPSZ) was deposited on a low carbon steel substrate using APS technique. Important microstructural properties of WC-Ni/ YPSZ coating such as splat boundaries, pore and grain morphology, microcracks, phase composition, elemental distribution of coatings, and lattice parameters of the crystals were investigated using optical microscopy, scanning electron microscopy ( SEM), energy dispersive X-ray ( EDS), and X-ray diffractometry ( XRD). A good adhesion was observed between different phases in tungsten carbide mixed with zirconia coatings. Decarburization process which occurred during APS process resulted in formation of tungsten hemi-carbide (W2C) phase in plasma sprayed samples. The calculated crystal size for APS-deposited coating was smaller than those of feedstock powder. [ABSTRACT FROM AUTHOR]

• The classification of MOF-based material for FSSCs electrode is summarized. • The typical fabrication techniques for MOFs-based FSSCs are thoroughly discussed. • A broad overview of reported MOFs-based flexible devices is provided. • The perspective on the development of MOFs-based electrodes for FSSCs is present. The recent rapid growth in Metal-organic Frameworks (MOFs)-based supercapacitors (SCs) has reached the level where there is a need for meet the demand of portable and wearable electronic equipment. Herein, we focus on the recent progresses toward the MOFs-based flexible solid-state supercapacitors (FSSCs). Some pristine MOFs used for the FSSCs have been reported, but it is usually restricted by its low conductivity. Now, there have the three strategies to improve the conductivity of MOFs material: exploiting new pristine conductive MOFs, developing the different multifunctional MOFs-based composite materials and obtaining the MOFs-derived materials. In this review, the classification of MOFs-based material for FSSCs electrode materials, together with the typical fabrication techniques for MOFs-based flexible devices, are totally discussed. A summary of the overall electrochemical performances and current development of the reported MOFs-based material assembled devices are presented gradually to predict the future tendency toward the actualization of an ultimate-performance MOFs-based FSSCs. [ABSTRACT FROM AUTHOR]

Abstract: MnO2 and carbon nanotubes (CNT) composite electrodes have been built on the interdigital stack layers of Fe–Al/SiO2 and Fe–Al/Au/Ti/SiO2 for the electrochemical micro-capacitors, using photolithography and thin-film technologies. The electrode properties and the performance of micro-cells are measured and analyzed with cyclic voltammetry (CV), impedance spectroscopy, and galvanostatic charge/discharge test in 0.1M Na2SO4 electrolyte. The vertically aligned CNT, grown on Fe–Al/SiO2, is more suitable for supporting the pseudocapacitive MnO2 than the random CNT on Fe–Al/Au/Ti/SiO2, but ohmic resistance of the former electrode is higher. We have prepared three cells on each stack layer with different electrode materials. The Ragone plot shows systematic variations in power and energy performance, reflecting their differences in electrode structure and polarization loss. The asymmetric cell of a pseudocapacitive positive electrode, loaded with MnO2 and CNT, exhibits a small IR drop and a high specific energy during discharge. Built on Fe–Al/SiO2, this asymmetric cell discharges at specific power 0.96kWkg−1 with specific energy 10.3Whkg−1; while on Fe–Al/Au/Ti/SiO2, the asymmetric cell discharges at power 1.16kWkg−1 with energy 5.71Whkg−1. [Copyright &y& Elsevier]

Abstract: A novel silicon-based glassy composite anode material with high initial coulombic efficiency and long cycling performance for lithium-ion batteries was synthesized by a wet mechanochemical reduction method. The in situ formed Si particles with size of 5–10nm were uniformly distributed in the glassy matrices formed by B2O3 and P2O5. The as-prepared composite electrode revealed an initial charge and discharge capacity of 432.7 and 514.4mAhg−1, respectively, with an initial coulombic efficiency of 84%. After 100cycles, the reversible capacity retention rate was still up to 97%, meaning a favorable cycling stability. [Copyright &y& Elsevier]

Abstract: To enhance the field emission characteristics, needle-like ruthenium dioxide (RuO2) nanocrystals (NCs) were grown on vertically aligned carbon nanotubes (VACNTs) using metal organic chemical vapor deposition (MOCVD). The VACNTs were the principal part and template with the needle-like RuO2 NCs grown outwardly from the VACNTs. Each needle-like RuO2 NC can be regarded as an individual field emitter, resulting in field emission site enhancement. The results demonstrated that the RuO2/VACNTs composite is an emitter material with great potential. [Copyright &y& Elsevier]