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Pomegranate-shaped Sn/SnO x /nanocarbon composites are fabricated via a simple one-step solvothermal method. The Sn and SnO x nanoparticles are uniformly embedded in the sheet-like nanocarbon membranes. As the anode of lithium-ion battery, the pomegranate-shaped Sn/SnO x /nanocarbon composites exhibit ultrafast-charging and long-life performance. At super high current rate of 10 C, 15 C and 20 C (the charging process is shortened to merely 6, 4 and 3 min, respectively), the reversible capacity of pomegranate-shaped Sn/SnO x /nanocarbon composites is 545, 467 and 421 mAh g −1 , respectively. After 2000 cycles, the capacity can still maintain at 192, 139 and 101 mAh g −1 at 10 C, 15 C and 20 C rate, respectively. Even after 5000 cycles at 15 C rate, the discharge capacity can still keep at 135 mAh g −1 . Such superior performance can be attributed to the unique structure, good electronic conductivity, short paths for lithium diffusion and interfacial charging mechanism. The present results indicate a new way to produce pomegranate-shaped metal/metal-oxide/nanocarbon composites with ultrafast-charging/long-life lithium-storage performance. [ABSTRACT FROM AUTHOR]

The effect of 2–8 mol.% Mo and 4 mol.% C additions on magnetic properties of TiC–10TiN–30Ni (mol.%) cermet was investigated. Saturation magnetization M s , remanence M r and Curie temperature T c of as-sintered cermets (1420 °C, 1 h) decreased with increasing Mo. This was mainly attributed to that the total content of non-magnetic alloying elements Mo and Ti in Ni-based binder phase increased with increasing Mo in cermets, leading to the weakening of magnetic exchange interaction among Ni atoms in binder phase. The further addition of 4 mol.% C inversely increased M s , M r and T c of cermets, which was mainly attributed to that it decreased the total content of Mo and Ti in binder phase, leading to the strengthening of magnetic exchange interaction among Ni atoms in binder phase. T c of cermets without C addition was about 250 K at 6 mol.% Mo and 115 K at 8 mol.% Mo, respectively, and that of cermets with 4 mol.% C addition was about 194 K at 8 mol.% Mo. [ABSTRACT FROM AUTHOR]

Liquid phase deposition (LPD) technique was employed to prepare α-Fe 2 O 3 films for photoelectrocatalytic degradation of pollutants. The obtained LPD films were characterized by various surface analysis techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS). The results indicated that α-Fe 2 O 3 films with porous structure were successfully deposited on the titanium substrates by the LPD process. The UV–Visible diffuse reflectance spectroscopic (DRS) analysis showed that the obtained LPD α-Fe 2 O 3 film mainly absorbed visible light, which was advantageous to the utilization of solar energy. Under visible light illumination, the Fe 2 O 3 film electrodes exhibited sensitive photocurrent responses, which were affected by the calcination temperature. Consistent with the photocurrent analysis, the α-Fe 2 O 3 film calcined at 600 °C showed the best photoelectrocatalytic performance, and different organic pollutants such as methyl orange (MO) and p -nitrophenol (PNP) were effectively degraded over the LPD film electrode by photoelectrocatalytic treatment under visible light illumination. [ABSTRACT FROM AUTHOR]

Metal sulfides are considered as promising anodes for lithium-ion batteries (LIBs) because of their high capacity. Among all of these metal sulfides, Tin(II) sulfide (SnS), possessing a unique 2D structure and with high lithium storage capacity, attract more attention as a promising anode for LIBs. However, serious volume change, sluggish kinetics, and low electric conductivity during the charging/discharging process, lead to poor rate capability and fast capacity fading. Herein, a ZnS/SnS@C yolk-shell microspheres (ZSS@NC) is synthesized through a facile hydrothermal process coupled with a PPy coating and sulfidation-in-microsphere strategy. The built-in electric field generated from ZnS/SnS heterostructure benefits the rapid transport of Li-ion and enhances the electric conductivity. Meanwhile, the N-doped carbon further improves the electronic conductivity and provides a robust support architecture, which can mitigate the volume variation of ZnS/SnS during the lithiation/delithiation process. Therefore, the ZnS/SnS@NC delivers high capacity (775.5 mA h g−1 at 200 mA g−1 after 200 cycles), outstanding rate performance (395.8 mA h g−1 at 5 A g−1), and superior long-term cycling performance (571.2 mA h g−1 at 1 A g−1 after 1000 cycles). • ZnS/SnS@C microspheres are synthesized through a facile hydrothermal process coupled with a PPy coating. • The built-in electric field generated from ZnS/SnS heterostructure benefits the rapid transport of Li-ion. • The N-doped carbon can improve the electronic conductivity and mitigate the volume variation. • The ZnS/SnS@NC composite presents long-life cycle performance and superior rate capability. [ABSTRACT FROM AUTHOR]

Layered double hydroxides (LDHs) containing transition metals with unsaturated d-bands are ideal candidates for oxygen evolution reaction (OER). However, the bulk layers and congested interlayers block the active sites and avoid the electrolyte access to the internal space. In this work, we report a simple coprecipitation coupled with the hydrothermal method for the direct growth of bimetallic NiCo-LDHs (5.01 nm), NiMn-LDHs (3.45 nm) and trimetallic NiCoMn-LDHs nanosheets (1.26 nm) on Ni foam and these fabricated electrodes exhibit the superior performance for OER. Notably, the NiCoMn-LDHs nanosheets exhibit the lowest overpotential of 290 mV at 20 mA cm−2 and the smallest Tafel slope of 87 mV dec−1, reducing by 20–40 mV and 31–39 mV dec−1 in comparison with those of bimetallic NiCo-LDHs (310 mV, 118 mV dec−1) and NiMn-LDHs (330 mV, 126 mV dec−1). This excellent performance is attributed to the 2D structure of the nanosheets and an abundance of exposed active sites, especially oxygen vacancies. Additionally, NiCoMn-LDHs nanosheets exhibit the smallest charge transfer resistance (R ct) of 6.3 Ω and the largest electrochemical double layer capacitance (C dl) of 5.52 mF cm−2 than those of the bimetallic NiCo-LDHs (11.0 Ω, 4.85 mF cm−2) and NiMn-LDHs (30.6 Ω, 3.00 mF cm−2). Furthermore, NiCoMn-LDHs nanosheets maintain good durability over 10 h and cyclic stability without distinct change. This work offers a facile strategy to design various types of bimetallic and trimetallic LDHs boosting for OER process. • Ultrathin LDHs nanosheets on Ni foam are successfully synthesized. • Ultrathin LDHs nanosheets expose an abundance of active metal sites. • The NiCoMn-LDHs on Ni foam show excellent OER activity. • Abundant oxygen vacancies and cooperative effects impart superior performance. [ABSTRACT FROM AUTHOR]

(Ti 1-x W x )C solid solutions (x = 0.05, 0.15, 0.25, 0.35) were synthesized by carbothermal reduction and then were used as hard phases to prepare (Ti,W)C-Ni 3 Al cermets by vacuum sintering. (Ti,W)C-Ni 3 Al cermets showed weak core-rim structure carbide particles embedded in Ni 3 Al binder. As W content in (Ti,W)C increased, core-rim structure of carbide particles got weaker and the contrast of particles lowered down in SEM-BSE morphologies. Furthermore, the densification of cermets was promoted with W content in solid solution increasing, meanwhile TRS and toughness of cermets were improved obviously. In this paper, the wettability of molten metal on different group transition metal carbides was discussed in detail based on valence-electron configurations (VECs) of carbides. [ABSTRACT FROM AUTHOR]

As an efficient energy storage device, supercapacitor has attracted increasing attention from researchers. However, there are two major problems that hinder the commercialization of electrode materials. First, the morphology and structure of electrode materials are not reasonable and the specific surface area is small, which leads to insufficient active sites; second, it is difficult to reach the theoretical specific capacitance due to the poor conductivity of active materials. Dealloying is a technical means that takes into account the design of material morphology and its phase structure. Porous metal materials prepared by dealloying have the characteristics of controllable morphology, simple preparation method and rapid reaction, so they have been widely used in electrode materials of supercapacitor. In this review, firstly, the dealloying preparation methods and materials suitable for electrode materials are introduced, and then, how to prepare materials from two aspects of morphology and phase composition design by dealloying technology is introduced in detail. Finally, the existing problems of the present stage dealloying technology in the electrode materials of supercapacitor and the future development direction are pointed out. • Summary of the application of dealloying methods to supercapacitors from a morphological and phase structure perspective. • Based on many research phenomena, a two-dimensional model of dealloying corrosion structure is proposed. • Suggestions are put forward for the development of dealloying in the field of supercapacitors. [ABSTRACT FROM AUTHOR]

TiC–9.0TiN–19.5WC–0.5Cr 3 C 2 –0.3C–38.0(Ni– x Cr) ( x = 0, 10, 20 and 30 wt.%) cermets were prepared, to investigate microstructure and mechanical properties of Mo-free Ti(C,N)-based cermets with Ni– x Cr binders. 20–30 wt.% Cr in binders led to the obvious increase of the dissolution rate of WC, which was mainly attributed to the decease of the solid/liquid transition temperature of Ni-based binder phase. In the final microstructure, Ti(C,N) grains exhibited two kinds of the core/rim structure: one consisted of black core, white inner rim and grey outer rim, and the other consisted of white core and grey rim. Ti(C,N) grains with black core were on the whole larger in size, independently of Cr content in binders, and their grey outer rim increased in thickness with the increase of Cr content in binders. More often than not, white inner rims were thin and incomplete in shape, and there were fine white speckles in black cores, when Cr content in binders reached 20–30 wt.%. Lattice parameter of Ni-based binder phase increased with the increase of Cr content in binders, which was attributed to that the total amount of such alloying elements as Ti, W and Cr in this phase increased with the increase of Cr content in binders, and however, it increased slightly when Cr content in binders was in the range of 10–20 wt.%. Transverse rupture strength reached a peak value when Cr content in binders was 20 wt.%, and hardness increased with the increase of Cr content in binders. [ABSTRACT FROM AUTHOR]

Transition metal phosphides (TMPs) have emerged as highly promising electrocatalysts for the hydrogen evolution reaction (HER) due to their earth-abundance reserves, rich electrochemical active sites and high stability. Herein, to cope with the inert atoms on the basal plane and sluggish electrochemical kinetics, we propose a novel strategy involving the in-situ conversion of urchin-like NiCo-LDH into a nitrogen-doped NiCoP electrocatalyst on nickel foam (N-NiCoP/NF) via a hydrothermal-phosphorylation approach. In this structure, NiCoP nanoneedles are assembled into a tip-rich urchin-like structure on NF substrates, delivering abundant mismatched active sites for capturing catalytic intermediates, accelerating charge transport and constructing an optimized heterogeneous interface. Additionally, heterogeneous N-atom doping can further regulate the charge distribution of NiCoP needles, and significantly contribute to enhancing the electrocatalytic performance for HER. Benefitting from the synergistic effect of the abundant active sites provided by tip-rich NiCoP nano-urchin, electronic modulation by heterogeneous N-species and optimized interfacial coupling, the N-NiCoP/NF electrocatalyst displays low overpotentials of 75 mV and obtains 10 mA cm−2 in alkaline electrolyte without significant decrease even after 5000 cycles, indicating high catalytic activity and stability. This study provides a low-cost and controlled approach for developing novel heteroatom-doped TMPs for HER applications.The various properties of the materials surprisingly demonstrate that our diatomic codoping strategy prepared by facile hydrothermal phosphatization with annealing can effectively enhance the HER properties of the materials. The unique morphology possessed by the material provides advantages such as active sites and accelerated charge transport that can further enhance the catalytic performance of the material, which is further formalized by our DFT calculations. Our theoretical and experimental studies provide a good case for the development of simple and low-cost electrocatalytic materials. • A tip-rich N-NiCoP/NF nano-urchin electrocatalysts is fabricated for HER via a hydrothermal-phosphorylation approach. • The N-NiCoP/NF electrocatalyst exhibits optimal HER catalytic performance in alkaline electrolyte. • Tips of N-NiCoP nano-needles can capture catalytic intermediates, accelerating charge transportation and optimizing hetero-interface. [ABSTRACT FROM AUTHOR]

MnS is considered as a potential anode own to its merits of high specific capacity, suitable voltage potential, and unique α→β phase transition reaction. Nevertheless, its intrinsic low conductivity, volume variation, and polysulfide dissolution during the lithiation/delithiation process, resulting in inferior cycling performance, then limit its practical application for LIBs. Herein, a novel anode material composited of Mn-Sn bimetallic sulfides heterostructure and N-doped carbon shell (MnS/SnS@NC) is designed. In such a designed MnS/SnS@NC composite, the N-doped carbon is tightly wrapped in the inner MnS/SnS heterostructure through the C-S-Mn bond, which is beneficial to keep the structural stability and enhance the electrochemical reaction kinetics during the lithiation/delithiation process. Furthermore, the heterostructure boosts the ion and electron transfer, and the N-doped carbon buffers the volume change during the cycling process. As a result, the MnS/SnS@NC delivers an excellent long-cycle performance (719.6 mAh g−1 at 1.0 A g−1 after 1000 cycles) and an outstanding rate performance (416.6 mAh g−1 at 5 A g−1). [Display omitted] • A novel heterostructure composited of Mn-Sn bimetallic sulfides was synthesized. • The carbon coating method was dopted via a simple metal chelate-assisted method. • The heterojunctions and N-doped carbon layer co-construct an advanced LIBs anode material. • The MnS/SnS@NC composite exhibits stable cycle performance and superior rate capability. [ABSTRACT FROM AUTHOR]

Abstract The Ti-based composites reinforced by in-situ formed TiB and TiC particles were successfully produced by laser powder-bed fusion (LPBF) additive manufactured technology using a B 4 C/Ti composite powder mixture, in order to further enhance the mechanical properties of commercially pure titanium (CP-Ti). The effects of applied laser energy density on the microstructure and attendant mechanical properties of the LPBF-processed parts were investigated, and meanwhile, the underlying formation mechanisms of the TiB and TiC particles by LPBF were elucidated. It showed that the whisker-like TiB and near-granular TiC reinforcements were in-situ formed through a laser-induced reaction of Ti-B 4 C system via a diffusion-nucleation-growth mechanism from the melt. The in-situ reinforcements arranged from dendrite to cellular morphology were primarily determined by the thermal convections that transformed from dendrite to annular patterns as a result of the great elevation of temperature gradient between molten Ti liquid and heated B 4 C particles as an increase in the applied laser energy density. The tensile tests revealed that the LPBF-ed Ti-based composites possessed an enhanced tensile strength from 893 ± 5 MPa to 1211 ± 8 MPa and a slightly reduced elongation from 18.1% to 16.8% with the transition of typically fracture morphologies from elongated dimples to equiaxed-ultrafine dimples, respectively, attributed to the combined grain refinement and microstructure strengthening effects. Highlights • Ti-based composites with novel reinforcements were produced through laser powder-bed fusion. • Thermal convection induced by laser energy input is responsible for the arrangement of in-situ TiB-TiC reinforcements. • Composite with dendrite-shaped exhibits a low tensile strength in comparison to that with cellular one. [ABSTRACT FROM AUTHOR]

Abstract The present work investigated magnetic and mechanical properties of TiC– x TiN–15MC– y Ni (wt.%, MC = Mo 2 C, WC, x = 0, 3, 6, 9, 12, 15, and y = 20, 40) cermets. Room-temperature (RT) saturation magnetization M s of Mo 2 C-containing and WC-containing cermets decreased with increasing x , and that of Mo 2 C-containing cermets was lower at the same x and y. Ferromagnetism disappeared at RT for Mo 2 C-containing cermets regardless of x and y and for WC-containing cermets at x = 15 for y = 20 and x ≥ 12 for y = 40, mainly due to high total content of non-magnetic Mo (or W) and Ti in binder phase. At x = 15, Curie temperature T c of Mo 2 C-containing cermets decreased to about 97 K for y = 20 and 16 K for y = 40. For Mo 2 C-containing cermets, transverse rupture strength (TRS) and hardness reached the maximum at x = 6 for y = 20, and they increased with increasing x for y = 40. For WC-containing cermets, TRS reached the maximum at x = 6 whereas hardness decreased slowly with increasing x for y = 20, and TRS and hardness reached the maximum at x = 12 and 6 for y = 40, respectively. TRS and hardness of Mo 2 C-containing cermets were higher than those of WC-containing cermets at the same x and y , except x = 0, 15 for y = 20, mainly due to stronger ceramic grain refinement strengthening effect and stronger substitutional solid-solution strengthening effect of binder phase. Highlights • RT M s of cermets decreased with increasing TiN content, regardless of MC. • Ferromagnetism of cermets disappeared at RT for MC = Mo 2 C, regardless of x and y. • Ferromagnetism of cermets disappeared at RT for MC = WC at x = 15 for y = 20, 40. • For MC = Mo 2 C, T c of cermets decreased to ∼97 K for y = 20 and ∼16 K for y = 40. • TRS and hardness of cermets were generally higher for MC = Mo 2 C than for MC = WC. [ABSTRACT FROM AUTHOR]

Microstructure and shear strength of Ti(C,N)-based cermet/Cu 30Ag 3Ti filler metal/W9Mo3Cr4V steel joints were investigated after brazing in vacuum at 870, 910, and 950 °C for 20 min, and 910 °C for 10, 20, 30 and 40 min. The reaction layer of Cu Ni Ti solid solution between cermet and filler metal was difficult to form during brazing at 870 °C, leading to very low shear strength of joints. During brazing at 910 °C, Cu Ni Ti solid solution was formed between cermet and filler metal, and it became thick with the increase of holding time. Shear strength of joints reached a peak value for 30 min, due to the appropriate thickness of Cu Ni Ti solid solution. During brazing at 950 °C, Cu Ni Ti solid solution was formed and then grew on the whole along with Ag-based solid solution in filler metal, but was not formed between cermet and filler metal, thus deteriorating shear strength of joints. [ABSTRACT FROM AUTHOR]

The exploration of promising anode materials with high capacity represent great challenge for LIBs and SIBs. Zinc sulfide (ZnS), has attracted more attention owing to its high capacity and abundant resource. However, the poor cycle performance have seriously hinder the practical application, which induced by the seriously volume expansion during the lithiation process. In this work, in-situ growth of the ZnS nanoparticles (NPs) on 3D N-doped carbon architecture (ZnS/NC) have been prepared by a simple method. In such a architecture, the N-doped carbon can not only avoid the volume change of ZnS, but also much improve the conductivity of hybrids, as well as facilitate a fast ions/electrons transport. As a result, the ZnS/NC composite exhibits outstanding cycle performance (377.1 mAh g−1 after 400 cycles at 1.0 A g−1) and outstanding rate performance (404 mA h g−1 at 3 A g−1) for LIBs. As for SIBs, a high reversible capacity of 244.1 mAh g−1 is obtained after 900 cycles at 1.0 A g−1, and high even at 3.0 A g−1, high reversible capacity of 241 mAh g−1 is also achieved, demonstrating excellent cycling performance and rate performance. • ZnS nanoparticles decorated on 3D N-doped carbon architecture was synthesized. • The N-doped carbon architecture can maintain structural stability during cycling process. • ZnS/NC composite exhibit high reversible capacity and outstanding cycling performance for LIBs. • ZnS/NC composite demonstrate long-term cycling stability and excellent rate capability for SIBs. [ABSTRACT FROM AUTHOR]