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Functional surfaces that enable both hot water repellency and effective condensation have attracted great interest in both academic research and practical applications. Two kinds of 1-alkyl-3-methylimidazolium hexafluorophosphate ionic liquids (ILs) with different chain lengths ([C n mIm][PF 6 ], n = 4 ([BmIm][PF 6 ]), n = 8 ([OmIm][PF 6 ])) are respectively infused into the porous surface constructed by nanocone arrays of (Ni,Co)-(CO 3 ) 0.5 (OH) 0.11 H 2 O (NiCo-NCA), aiming to produce slippery surfaces (SSs) with stable non-wetting performance. Before the ILs infusion, the NiCo-NCA surface is functionalized by low surface energy material for conferring superhydrophobicity. The superhydrophobicity of the modified NiCo-NCA becomes ineffective after the heat treatment up to about 240 °C due to the formation of cracks on the surface. However, the slippery surfaces can be maintained in the ILs-infused samples followed by the same heat treatment due to the self-healing ability and thermal stability of the infused fluids. Moreover, hot water droplets are repellent on the ILs-infused SSs while pinned on the superhydrophobic surface. The nucleation process of condensing water droplets is easier on the ILs-infused SSs than that on the superhydrophobic surface. The sliding speed of the condensed water and the hot water droplets on the [OmIm][PF 6 ]-infused SS are slower than those on the [BmIm][PF 6 ]-infused SS due to the higher viscosity of [OmIm][PF 6 ]. As well, the ILs-infused SSs can endure physical damage and impacting droplet. The ILs-infused SSs shows promise potential applications in hot liquid self-cleaning and high efficiency droplet manipulation. [ABSTRACT FROM AUTHOR]

The ZrN/Zr/a-C multilayered coatings were deposited onto Ti6Al4V and Si substrates using a closed field unbalanced magnetron sputtering. The morphology and microstructure of the multilayers were performed by scanning electron microscopy (SEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM). The multilayer consists of a-C layers, Zr layers and ZrN layers. The Zr interlayers can improve the weak adhesion between a-C layers and ZrN layers. The multilayer exhibits a low residual stress of − 0.5 GPa and a hardness of 18.7 GPa. The tribological properties were evaluated by a ball-on-disk tribometer. The friction coefficient and wear rate of the multilayer in fetal bovine serum (FBS) kept very low values during sliding at an applied load of 2 N, which indicated excellent long-term wear resistance. What is more, the multilayer also presented a low wear rate in FBS even at a high applied load of 10 N. Additionally, the corrosion resistance of Ti6Al4V in Hank's solution is significantly improved by the multilayer. This study demonstrates that the ZrN/Zr/a-C multilayer exhibits excellent performance including low residual stress, high corrosion resistance as well as good bio-tribological properties and it is proper to protect Ti6Al4V alloy. [ABSTRACT FROM AUTHOR]

Platinum/exfoliated Ni-Al layered double hydroxides (LDHs)/reduced graphene oxide (rGO) ternary composite (Pt/LDH/rGO) as a highly active electrocatalyst for efficient methanol oxidation reactions (MORs) was fabricated by a facile self-assembly method with controlling electrostatic interactions between precursors. The introduction of 2D atomic layers of Ni-Al LDH sheet is of vital importance for the removal of poisonous carbonaceous intermediates on Pt surface in the methanol oxidation process due to its outstanding performance in dissociative absorption of water molecules. Structural characterizations show that the active Pt particles with a size range of 3–5 nm are uniformly dispersed on the LDH 2D platelets and the rGO sheet acts as a conductive supporter for the Pt/LDH composites. An in-situ reactivation process for recovery of Pt activity is proposed in virtue of different working potential ranges between Ni-Al LDH and Pt in alkaline solution. Under periodic reactivation, the activity of Pt can be fully recovered without renewing the reaction solution. Electrochemical tests show that the as-prepared ternary composite exhibits better activity and durability towards MOR than the commercial Pt/C catalyst. [ABSTRACT FROM AUTHOR]

A novel ionothermal strategy for developing a chemical conversion film on magnesium alloys is proposed based on the interaction of a deep eutectic solvent (DES) with the substrate. Upon heating the choline chloride/urea mixture-based DES can react with the AZ31B magnesium alloy surface to form a promising anti-corrosion conversion film. Interestingly, the chemical conversion film is mainly composed by MgH 2 and MgCO 3 phases. The as-grown conversion film exhibits superhydrophobicity after surface modification in a stearic acid/ethanol solution. Electrochemical tests and visual investigations indicate the corrosion resistance of the magnesium alloy can be improved by the conversion film. [ABSTRACT FROM AUTHOR]

A novel electrocatalyst for methanol oxidation reaction in alkaline medium is elaborately fabricated by a sponge-template method involving an electroless plating of amorphous Ni–P on sponge and the following annealing process at 500 °C in air. The electrocatalyst is characterized by NiO nanoparticle/nanoflake grown on the Ni–P alloy tube. The vital annealing process aims to remove templates, crystallize Ni–P, and generate NiO nanostructures on the outside surface of Ni–P tubes, thus leading to the final structure of NiO/Ni–P composites. The tubular Ni–P framework surface is decorated with microspherical NiO (EP-M) or nanoflake NiO (EP-F), which strongly depends on the electroless plating time. For comparison, porous NiO nanoflakes are also synthesized by chemical bath deposition. The EP-M containing ∼83.8 wt.% NiO and ∼16.2 wt.% Ni–P has the largest BET surface area of 210.03 m 2 g −1 among the three samples. Moreover, the EP-M exhibits a high current density (∼467 A g −1 ) and long-term chronoamperometry stability (≥20,000 s) toward methanol oxidation in alkaline solution. The improved catalytic activity of the composite catalyst might be attributed to the strong electronic interaction between NiO and Ni–P as revealed by X-ray photoelectron spectroscopy. [ABSTRACT FROM AUTHOR]

A facile one-pot solvothermal method is proposed to fabricate a new series of Ni-Co-P-O compound-based electrocatalysts for methanol oxidation in alkaline environment. It is found that the chemical composition, surface morphology, as well as the crystallographic structure of the final Ni-Co-P-O composites are largely depends on the Co 2+ /Ni 2+ molar ratios in the reaction system. The sample of NiCoPO-2 possessing an urchin-like architecture and a hybrid composition of nano-scaled Ni/Co phosphides and phosphates was produced at a Co 2+ /Ni 2+ molar ratio of 0.18. A larger specific surface area of 540.5 m 2 g −1 and a bimodal pore size distribution are found in the NiCoPO-2 sample. As a potential catalyst, the NiCoPO-2 delivers a highest oxidation current density (∼1567 A g −1 ) and a good durability (≥20000 s) toward the methanol electrooxidation reaction. The superior catalytic performance of the NiCoPO-2 catalyst should be attributed to its unique microstructure and compositions. It is also supposed that the formation of electron tunneling junctions between the metal phosphides and phosphates could provide new channels for facilitating electron transfer throughout the composite electrocatalysts. [ABSTRACT FROM AUTHOR]

Adsorption is often time consuming due to slow diffusion kinetic. Sizing he adsorbent down might help to accelerate adsorption. For CoFe spinel oxide, a magnetically separable adsorbent, the preparation of nanosheets faces many challenges including phase separation, grain growth and difficulty in preparing two-dimensional materials. In this work, we prepared porous CoFe oxide nanosheet with chemical formula of Co 2.698 Fe 0.302 O 4 through topochemical transformation of a CoFe precursor, which has a layered double hydroxide (LDH) analogue structure and a large interlayer spacing. The LDH precursor was synthesized from a cheap deep eutectic solvent (DES) system. The calcined Co 2.698 Fe 0.302 O 4 has small grain size (10–20 nm), nanosheet morphology, and porous structure, which contribute to a large specific surface area of 79.5 m 2 g −1 . The Co 2.698 Fe 0.302 O 4 nanosheets show fast removal ability and good adsorption capacity for both organic waste (305 mg g −1 in 5 min for Congo red) and toxic heavy metal ion (5.27 mg g −1 in 30 min for Cr (VI)). Furthermore, the Co 2.698 Fe 0.302 O 4 can be separated magnetically. Considering the precursor can be prepared through a fast, simple, surfactant-free and high-yield synthetic strategy, this work should have practical significance in fabricating adsorbents. [ABSTRACT FROM AUTHOR]

Manganese oxides with desired structure are controllably obtained through annealing MnCO 3 precursors with required structures. The structures of MnCO 3 precursors are determined by a “mesocrystal formation” process in an ionic liquid system of a choline chloride/urea (CU) mixture. Without addition of surfactants, only CU solvent and manganese chloride are needed in the reaction system, in which the CU acts as reaction medium as well as control agent for particle growth. A shape transformation of MnCO 3 particles from well-defined rhombohedral mesocrystals to ellipsoidal polycrystal ensembles, and to nanoparticulate aggregates is observed when heating the reaction system for 4 h at 120, 150, and 180 °C, respectively. With a longer aging time at 120 °C, etching and disassembly of MnCO 3 mesocrystals happened. The correlation between the microstructure and the underlying formation mechanism is highlighted. Porous and nanowire-like MnO x nanostructures are obtained through a facile thermal conversion process from the diverse MnCO 3 precursors, which are demonstrated as effective and efficient adsorbents to remove organic waste (e.g. Congo red) from water. Significantly, the nanowire-like MnO x nanostructures obtained by annealing the MnCO 3 mesocrystals at 300 °C for 4 h can remove about 95% Congo red in waste water at room temperature in only one minute, which is superior to the reported hierarchical hollow nanostructured MnO 2 . [ABSTRACT FROM AUTHOR]

Abstract: A NiO–graphene hybrid film with 3D hierarchically porous structure has been rationally designed and constructed through a series of controlled fabrication processes. Multilayered porous graphene sheet network with the pore size of several micrometers is created via a so-called “on-water spreading” method, which is facile, economical, efficient and scalable. Then, the cross-like NiO nanoflakes film is uniformly grown onto the porous graphene sheet framework by a chemical bath deposition. The NiO–graphene hybrid film exhibits specific capacitance of 540 F g−1 at 2 A g−1 with 80% capacitance retention after 2000 cycles in 2 M KOH aqueous solution, which is much higher than that achieved from the bare NiO nanoflakes film (370 F g−1, with 66% capacitance retention). Moreover, chronoamperometry and electrochemical impedance spectroscopy measurements reveal that the NiO–graphene hybrid demonstrates enhanced reaction kinetics with about only 50% of respond time for NiO/NiOOH reaction and 79% of charge-transfer resistance compared with those of the bare NiO film. The proposed strategy could offer an effective way to fabricate graphene-based electrode materials for applications in various energy-storage devices. [Copyright &y& Elsevier]

Abstract: Two NiO products with different microstructures have been obtained using a traditional NaOH-induced aqueous-phase precipitation and a homogeneous precipitation in choline chloride/urea mixture-based deep eutectic solvent (DES), respectively. The synthesis processes play a key role in the structure construction of NiO precursors as well as the final NiO products, and possible formation mechanisms are proposed. The DES-based homogeneous precipitation method provides plentiful nucleation sites, moderate crystal growth process and possible template effect, which could conduce to the production of flower-like NiO with continuously self-supporting mesoporous structure assembled by tiny grains. The flower-like NiO electrode exhibits higher current density, faster charge-transfer process, better electrode accessibility, and improved stability for methanol electro-oxidation in an electrolyte of 0.1 M CH3OH + 0.005 M KOH than the disorderly aggregated NiO nanoparticles. We believe that the DES-based homogeneous precipitation method can provide an effective approach to fabricate advanced electrocatalyst materials with homogeneous and well-assembled microstructure. [Copyright &y& Elsevier]

Abstract: The collective influence of crucial electrodeposition parameters (temperature, deposition voltage and bath composition) on the properties of Zn–Ni films electrodeposited in a choline chloride–urea eutectic-based ionic liquid was investigated. The microstructures, chemical compositions, phase structures and corrosion behaviors of electrodeposited films were analyzed using scanning electron microscope, energy dispersive X-ray spectroscopy, X-ray diffraction and linear cyclic voltammetry, respectively. The surface morphologies and chemical compositions of the films were strongly dependent on the electrodeposition parameters. It was found that the amounts of nickel in the Zn–Ni alloy films were significantly higher than that present in the electrolytes and was always above 50%, indicating normal codeposition mechanism. Electrodeposition of high Zn content alloy is favorable at high electrodeposition voltages, high temperatures and high Zn (II)/Ni (II) ratios. Electrochemical measurements shows that under the conditions considered, the Zn–Ni film from 0.45M Zn (II)–0.05M Ni (II) deposited at 55°C and 0.8V exhibits the highest barrier corrosion resistance compared with the other films and this was attributed to a dense, smooth and crack free morphology with optimum Zn content. [Copyright &y& Elsevier]

Highlights: [•] Ni-P films with different surface morphologies and thicknesses were successfully synthesized. [•] Ni-P films were grown based on Ni films which were electrodeposited using ionic liquids. [•] Ni2P film obtained by Ni electrodeposition for 30min exhibits a rough surface with plenty of pores. [•] Ni2P film delivered a discharge capacity of 398.5mAhg−1 with the capacity retention of 91.4%. [•] The film exhibits a capacity increase with cycling phenomena relating to its surface morphology. [ABSTRACT FROM AUTHOR]

Abstract: Nanostructured nickel oxide (NiO) thin films were prepared by a simple electrodeposition in choline chloride-based ionic liquid followed by an oxidation in air. Uniform granules and some voids opened between these granules were presented in the polycrystalline NiO films deposited for 10 and 30s, but the film became compact as the deposition time increased to 60s. The optical transmittance of the film decreased with the increase of the film thickness. All the NiO films exhibit high coloration efficiency, fast electrochromic switching and good cycling durability. The ultra fast switching time (0.74s and 0.88s) and maximum coloration efficiency of 250cm2 C−1 were observed for the film deposited for 10s. [Copyright &y& Elsevier]

Abstract: A comparative study was carried out on the deposition mechanism, microstructure, and corrosion resistance of Cu films electrodeposited from the base electrolyte of CuCl2·2H2O in a choline chloride–ethylene glycol eutectic solvent with absence and presence of the additive of ethylene diamine (EDA). The base electrolyte is unstable and produces rough Cu films with columnar grains. Upon the introduction of EDA, the modified electrolyte becomes stable and the nucleation of Cu deposits is strongly inhibited, thus producing a smooth and compact surface with finer grains. Uniform corrosion and decreased corrosion current density are recognized in the fine grained Cu films. [Copyright &y& Elsevier]

Abstract: Porous tin-based films are electrodeposited on copper foils from a choline chloride/ethylene glycol based electrolyte containing SnCl2·2H2O without any complexing agent or additive. Increasing the deposition time and voltage produces thicker films. The initially deposited Sn grains are relatively uniform with an average size of 200–300 nm and a kind of self-assembly distribution constructing an open and bicontinuous porous network. The architecture of these films possesses a double-layer structure, i.e. SnO2 (superficial layer)/Sn–Cu alloy (bottom layer), which is revealed by X-ray diffractometer and X-ray photoelectron spectroscopy. The electrochemical performance of the porous tin-based films as anode for lithium-ion batteries is measured. Although the capacity fades gradually with repeated cycling, a reversible capacity of 300-350 mAh g−1 is maintained for more than 50 cycles, which suggests that the in situ formed Sn--Cu alloy could provide an interlocking interface between active materials and current collector. Therefore, the tin''s shedding from the current collector can be restrained. Moreover, the inactive materials, such as the oxide in the superficial layer and the Cu in the bottom layer, could also act as buffers to relieve the induced volume expansion of Sn during the repeated lithiathion/delithiation process, thus giving the good cycle performances. [Copyright &y& Elsevier]

Abstract: Pure Ni and three Ni–Co alloys films, i.e. Ni–4wt.%Co, Ni–18wt.%Co, and Ni–40wt.%Co, are electrodeposited at room temperature from the choline chloride/ethylene glycol deep eutectic solvent dissolved by nickel or/and cobalt chlorides. Electrodeposition mechanism, microstructure, and corrosion properties of the films are investigated. Surface morphology and chemical composite of the films are significantly dependent on the Ni2+ and Co2+ concentrations in the electrolytes. Interestingly, it is found that the amount of cobalt in the Ni–Co alloy films is significantly lower than that present in the electrolytes, which indicates an absence of anomalous codeposition process for the non-aqueous electrolytes. However, anomalous codeposition of Ni–Co deposits is frequently observed for the aqueous electrolytes. The Ni–Co alloy films possess face-centered cubic structures and refined grains revealed by X-ray diffractometer and scanning electron microscope. Potentiodynamic polarization measurements show that the Ni film exhibits the noblest corrosion potential and the lowest corrosion current compared with the Ni–Co alloys films. Moreover, the more Co content the Ni–Co films have, the more negative corrosion potential and the higher corrosion current the films exhibit. [Copyright &y& Elsevier]

Abstract: A fully dense nanocrystalline (nc) Ni film on the brass substrate was fabricated by a simple electrodeposition from a choline chloride-based ionic liquid (choline chloride–ethylene glycol) at working voltage (between the two electrodes) of 1.0V and room temperature. It is found that the nc Ni with an average grain size of about 6nm has a face-centered cubic crystal structure. At the film/substrate interface, the epitaxial growth of some nc Ni grains on brass grains can be evidenced by the high resolution transmission electron microscope. The 6nm grain sized Ni exhibits a high strain rate sensitivity (m =0.051) and enhanced hardness values in the range of 7.6–9.7GPa. The deformation mechanism of the nc Ni under indentation is also discussed with the theoretical model fitting. The potentiodynamic polarization curve shows that the nc Ni film exhibits a much negative corrosion potential, which provides a sacrificial anode protection for the brass substrate. [Copyright &y& Elsevier]

Abstract: Carbon perfectly coated LiFePO4 cathode materials are synthesized by carbon-thermal reduction method using polystyrene (PS) spheres as carbon source. The PS spheres with diameters of 150–300nm used for the pyrolysis reaction not only inhibit the particle growth but also lead to uniform distribution of carbon coating on the surface of LiFePO4 particles. Rate capability and cycling stability of LiFePO4/C with the carbon contents ranging from 1.4wt% to 3.7wt% are investigated at −20°C. The LiFePO4/C with 3.0wt% C exhibits excellent electrochemical capability at low temperature, which delivers 147mAhg−1 at 0.1C. After 100 cycles at a charge–discharge rate of 1C, there is still 100% of initial capacity retained for the LiFePO4/C electrode at −20°C. According to the transmission electron microscope analysis and cyclic voltammetry measurement, this can be attributed to the good carbon coating morphology and optimal carbon coating thickness. [Copyright &y& Elsevier]

Abstract: This work attempts to reveal the microstructure of interface and the relation between interface mixing and hardening mechanism in TiN/CNx multilayer films. The growth and microstructure of these interfacial layers are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Investigation result indicates that the interface species are mainly composed of Ti–C–N, the growth of interlayer mainly depends on the deposition temperature. The thickest interlayer (about 2.5nm) is produced at 300°C, and the interlayer disappears at 500°C. Nanoindentation testing indicates that the film with a maximum interlayer thickness of about 2.5nm exhibits superhardness up to 40GPa. Based on the experimental results, it is suggested that the interfacial intermixing and the crystal quality of TiN are the main reasons for the superhardness effect in TiN/CNx nanostructured multilayers. [ABSTRACT FROM AUTHOR]

Abstract: A new route for silver electroless deposition on Si(100) substrate is developed based on the galvanic displacement process. The basic electroless bath contains NaF and AgNO3 with different concentrations. The morphologies of electrolessly deposited silver nanostructures, including silver nanowires and nanoparticles, are strongly dependent on the electrolyte composition. Adding an excess dosage of polyvinylpyrrolidone into the basic electrolyte yields final silver films of porous structures composed by multitudinous Ag nanoparticles. The porous silver films possess the surface hydrophobic property after the modification with n-dodecanethiol. Unidirectional wetting and spreading of a water droplet are also demonstrated on the patterned porous Ag films. [ABSTRACT FROM AUTHOR]

a-C/a-C:Ti multilayer films were deposited on medical Ti6Al4V alloy using a closed field unbalanced magnetron sputtering system with various substrate bias duty cycle. The tribological and corrosion behaviors of the multilayer films in Hank's solution were evaluated by a ball-on-disk tribometer and an electrochemical workshop. The duty cycle has a significant effect on the bonding structure, and mechanical and tribological properties of the films. The polarization resistance of the films on Ti alloy is approximately ten times more than that of Ti6Al4V which indicates that higher corrosion resistance can be achieved in Hank's solution at 37 °C. However, the polarization resistance and corrosion current do not change so much with the variation of duty cycle, implying that its influence on corrosion behavior of these a-C/a-C:Ti multilayer films is not so obvious. [ABSTRACT FROM AUTHOR]

Abstract: The surface of graphene is modified by nickel nanoparticles which are in-situ reduced from NiO nanoparticles by graphene. The nickel nanoparticles obtained are up to 10nm in size and are strongly anchored on the surface of graphene sheets. As an anode material for lithium ion batteries, the graphene–Ni hybrid material delivers a reversible capacity of 675mAhg−1 after 35 discharge/charge cycles at a current density of 100mAg−1, corresponding to 85% retention of the initial charge capacity. In addition, the graphene–Ni hybrid electrode exhibits much better rate capability compared to its pure counterpart operated at various rates between 200 and 800mAg−1. Such enhanced lithium storage performance of the graphene–Ni hybrid electrode can be ascribed to the enhanced electronic transport and Li+ migration through the solid electrolyte interphase (SEI) film as a consequence of that the anchored nickel nanoparticles increase the electronic conductivity and modify the structure of SEI film covering the surface of graphene. [Copyright &y& Elsevier]

Abstract: TiN/CN x multilayer films with bilayer periods of 4.5–40.3nm were deposited by direct-current magnetron sputtering. Layer morphology and structure of the multilayered films were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The TiN/CN x multilayers exhibited coherent epitaxial growth due to the mutual growth-promoting effect at small bilayer period and some crystalline regions going through the interface of TiN/CN x . Nanoindentation tests showed that the hardness of the multilayers varied from 12.5 to 31GPa, with the highest hardness being obtained with a bilayer period of 4.5nm. The tribological properties of the films were investigated using a ball-on-disk tribometer in humid air, and the TiN/CN x multilayer with a bilayer period of 4.5nm also exhibited the lowest friction coefficient and the highest wear resistance. [Copyright &y& Elsevier]

Abstract: Carbon nitride (CN x ) films were deposited by direct current magnetron sputtering at different N2 fractions and a substrate temperature of 450°C. The composition and microstructure of CN x films were investigated by high resolution transmission electron microscopy, X-ray absorption near-edge spectroscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. The CN x films change from amorphous to fullerene-like nanostructure as the N2 fraction is ranged from 0.05 to 0.1, and then to nitridized graphite nanocrystals in amorphous matrix at pure N2, and the curvature of the basal planes decreases with the increase of N content in CN x films. Meanwhile, the structural analysis provides the identification of spectral signatures related with the formation and promotion of FL arrangements, and the formation of C-sp3 sites has been generally considered as the cross-linking path in fullerene-like CN x . Their mechanical and tribological properties were also investigated in detail, aiming at illustrating excellent mechanical, friction and wear behaviours of the fullerene-like CN x film with respect to its high hardness and elastic recovery and less dependence on humidity and oxygen as compared with the amorphous CN x film. [ABSTRACT FROM AUTHOR]

Polypyrrole-coated high Na content Na 0.91 MnO 2 porous microcubes are prepared through high temperature calcination followed by a chemical ice water bath process. The higher sodium content of Na 0.91 MnO 2 makes capacity increase up to 50 mAh g−1 compared with Na 0.7 MnO 2.05. The thus wider interlayer space makes ion/electron insertion/extraction faster. Porous structure providing shorter ion/electron diffusion distance compared with hollow sphere structure. The conductive polymer modified sodium manganate oxide cathode for sodium ion full batteries exhibits ultrahigh initial capacity, cycling stability and rate capability. Highly conductive cathode material with enhanced Na+ diffusion kinetics is of great importance in the exploration of sodium ion batteries. In this work, Na 0.91 MnO 2 porous microcube which is coated with highly conductive polypyrrole (PPy) is obtained. The high Na content in the layered sodium manganate oxide brings about wider interlayer distance resulting in high capacity and electrochemical kinetics. The higher sodium content of Na 0.91 MO 2 makes capacity increase up to 50 mAh g−1 compared with Na 0.7 MnO 2.05. Furthermore, the well-designed combination between porous structure and conductive PPy coating exhibits fast ion/electron transfer inside the electrode and high cycling stability. The PPy coated Na 0.91 MnO 2 delivers a high initial capacity of 208 mAh g−1, encouraging capacity retention and rate capability. Based on the porous Na 0.91 MnO 2 @PPy cathode, the sodium ion full cells with puffed millet porous carbon anode show remarkably stable cycling and high-rate performances. [ABSTRACT FROM AUTHOR]

Tin oxide (SnO 2) has been widely used as an anode material for sodium-ion storage because of its high theoretical capacity. However, it suffers from large volume expansion and poor conductivity. To overcome these limitations, in this study, we have designed and prepared Mo-doped SnO 2 nanoflake arrays anchored on carbon foam (Mo-SnO 2 @C-foam with 38.41 wt% SnO 2 and 3.7 wt% Mo content) by a facile hydrothermal method. The carbon foam serves as a three-dimensional conductive network and a buffer skeleton, contributing to improved rate performance and cycling stability. In addition, Mo doping enhances the kinetics of sodium-ion transfer, and the interlaced SnO 2 nanoflake arrays is beneficial to promote the conversion reactions during the charge/discharge process. The as-prepared composite with a unique structure demonstrate a high initial capacity of 1017.1 mAh g−1 at 0.1 A g−1, with a capacity retention over three times higher than that of the control sample (SnO 2 @C-foam) at 1 A g−1, indicating a remarkable rate performance. [ABSTRACT FROM AUTHOR]

Improving the insulating nature of sulfur and retaining the soluble polysulfides in sulfur cathodes are crucial for realizing the practical application of lithium–sulfur batteries (LSBs). Biomass-based carbon is becoming increasingly popular for fabricating economical and efficient cathodes for LSBs owing to its unique structure. Herein, we report a facile strategy to transform bovine bone with an organic–inorganic structure into cellular hierarchical porous carbon via carbonization and KOH activation, followed by CoS 2 modification through hydrothermal treatment. The synthesized composite can load abundant sulfur and produce a dual effect of "physical confinement and chemical entrapment" on polysulfides. The conductive carbon frame with the developed porous structure provides adequate space to accommodate sulfur and physically suppress the shuttle effect of polysulfides. The embedded half-metallic CoS 2 sites can chemically anchor the polysulfides and enhance the electrochemical reaction activity as well. Owing to the multifunctional structure and dual restraint effect, the designed electrode exhibits enhanced electrochemical properties including high initial capacity (1230.9 mAh g−1 at 0.2 C), improved cycling stability and enhanced rate capability. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A 3D network GPE composed of PVDF-HFP and PETT-Ester is successfully fabricated. • The GPE exhibits a wide electrochemical window of 5.05 V (vs. Li/Li+). • The GPE effectively suppresses the extension of lithium dendrite. • The Li/GPE/S cell shows a high specific capacity retention. Abstract A UV-light polymerized three-dimensional (3D) network gel polymer electrolyte (GPE) is designed and fabricated for solid-state lithium-sulfur (Li-S) batteries. The GPE exhibits wide electrochemical window up to 5.05 V (vs. Li+/Li), outstanding thermostability and mechanical property. Besides, the GPE effectively suppresses the extension of lithium dendrite and the electron-donating groups in GPE inhibit the shuttle of lithium polysulfides. The assembled solid-state Li-S batteries with the 3D network GPE show high specific capacity retention of 69.1% after 300 cycles at 0.5 C. With the consideration of these, the GPE in this report undoubtedly provides an effective technique to design high performance solid-state Li-S batteries. [ABSTRACT FROM AUTHOR]

Abstract A compositive synthesis of gel polymer electrolytes by blending poly(propylene carbonate) (PPC) into poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) as a polymer host is proposed. The blending polymer is produced by a facile solution casting method and ester groups of PPC are successful introduced into PVDF-HFP. The gel polymer electrolyte displays an excellent ion conductivity of 1.18 × 10−3 S cm−1, broad electrochemical window up to 4.8 V (vs. Li/Li+) and outstanding electrochemical stability within rechargeable lithium batteries at room temperature. The improvement of ion conductivity is attributed to the decrease of polymer crystallizability and the increase of micro pores. The strategy of blending is promising for the modification of PVDF-HFP electrolyte and foreground application in next-generation solid energy conversion devices. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Exploring high performance cathode materials is of great means for the development of bi-functional electrochromic energy storage devices. Herein, Nb-doped WO 3 mesoporous films as integrated high-quality cathode are successfully constructed via a facile sol-gel method. Chemical state and crystallinity of the WO 3 based films are significantly influenced by doping concentration. Compared with the pure WO 3 , the optimal Nb-doped film shows improved optical-electrochemical properties with high specific capacity (74.4 mAh g−1 at 2 A g−1), excellent high-rate capability, large optical contrast (61.7% at 633 nm), and ultra-fast switching speed (3.6 s and 2.1 s for coloring and bleaching process, respectively). These positive features suggest the potential application of Nb-doped WO 3 mesoporous cathode. Our research paves the way for the development of multifunctional photoelectrochemical energy devices. [ABSTRACT FROM AUTHOR]

High-quality solid electrolyte is essential for the growing need of lithium ion batteries. Herein, we report a novel organic-inorganic composite electrolyte based on Li 7 La 3 Zr 2 O 12 ceramic powder incorporated into PVDF-HFP through a simple combined method. At room temperature, the composite polymer electrolyte (CPE) possesses a good ionic transmission improvement of 3.71 × 10 −4  S cm −1 . The CPE behaves a fine lithium ion transference number of 0.58 and an electrochemical window of up to 4.65 V. CPEs display meliorative electrochemical stability compared to pure PVDF-HFP electrolyte. The cathode presents an excellent initial discharge capacity of 163.1 mAh g −1 at 0.2 C in Li/CPE/LiFePO 4 cell. The cell with CPE displays much better capacity retention than that with pure PVDF-HFP electrolyte. The Li 7 La 3 Zr 2 O 12 modified PVDF-HFP is a promising electrolyte for lithium ion batteries. [ABSTRACT FROM AUTHOR]

Lithium metal has always been considered as a “Holy Grail” of anode materials for high-energy-density batteries owing to its extremely high theoretical gravimetric capacity of 3860 mAh g −1 and the lowest electrochemical potential of −3.04 V. Unfortunately, huge challenges including unlimited dendrite growth and complex interfacial reaction accompanied with relatively low Coulombic efficiency have extremely restricted its practical applications for decades. In this review, we discuss recently exciting achievements in modifying Li metal anodes, particularly regarding porous structure design, surface modification, heterogeneous seed strategy, potential substitutes including Li powder, and pre-lithiated composite. Although each improvement method has its own advantage, we believe appropriate combination of them will yield more promising results. Finally, we discuss core issues and potential opportunities of Li metal anode, expecting to shed new light on future research in this field. [ABSTRACT FROM AUTHOR]

Biomedical Ti6Al4V alloy exhibits excellent mechanical and anti-corrosion properties but poor wear resistance. In order to improve the combination performance of Ti6Al4V alloy, Zr-doped graphite-like carbon (GLC) nanomultilayer and nanocomposite coatings are deposited by magnetron sputtering. The microstructures of the coatings are characterized by transmission electron microscopy (TEM) and Raman spectroscopy. The Zr-doped GLC nanomultilayer shows low friction coefficient and wear rate at applied loads of 1 N and 3 N in Hank's solution. In addition, both the Zr-doped GLC nanomultilayer and nanocomposite coatings present high corrosion resistance, which results from the corrosion-resistant GLC and zirconium oxide. Compared to the Zr-doped GLC nanocomposite, the nanomultilayer is more promising in the applications under simultaneously tribological and corrosive conditions. [ABSTRACT FROM AUTHOR]

Design/fabrication of solid state electrolytes with high ionic conductivity is of great importance to develop next-generation Li ion batteries. In this work, the Li 7 P 3 S 11 glass-ceramic electrolyte is successfully synthesized by dissolution- evaporation approach. The solvent effect on the electrochemical performance of Li 7 P 3 S 11 is investigated by electrochemical impedance spectroscopy and chronoamperometry tests. The Li 7 P 3 S 11 electrolyte prepared by a solution of acetonitrile has a high ionic conductivity of 9.7 × 10 −4 S cm −1 at 298 K and a low activation energy of 31.2 kJ mol −1 . Impressively, a wide and stable electrochemical window up to 5 V (vs. Li/Li + ) is demonstrated between the solid electrolyte and lithium electrode. The developed dissolution-evaporation approach shows good industrial prospect due to its advantages of energy conservation and high efficiency. [ABSTRACT FROM AUTHOR]

Integral construction of lithium sulfide (Li 2 S) cathode is indispensable and vital for developing high-performance lithium-sulfur (Li-S) batteries. Herein we have demonstrated a facile strategy for fabricating free-standing carbon paper supported Li 2 S@C (P-Li 2 S@C) integrated cathode. The P-Li 2 S@C cathode is synthesized through simple pyrolysis of low-cost lithium sulfate (Li 2 SO 4 ) and chitosan, and embedded in the double carbon matrixes with carbon paper support and outer CVD-carbon layer. Li 2 S nanoparticles are homogeneously dispersed in the above designed double carbon matrixes. The P-Li 2 S@C cathode exhibits an initial discharge capacity of 820 mAh g −1 at 0.1 C and still maintains 430 mAh g −1 after 100 cycles, superior to the P-Li 2 S counterpart (480 mAh g −1 at 0.1 C and 150 mAh g −1 after 100 cycles). Our research verifies the effectiveness of double carbon modification on the Li 2 S, especially, the outer carbon coating not only improves the electrical conductivity of electrode, but also further prohibits the “shuttle effect” of polysulfides. [ABSTRACT FROM AUTHOR]

To meet the requirements for high-rate battery with desirable performance, a self-supported Ni 2 P@Ni sponge electrode is synthesized via simple steps, in which the Ni sponge substrate is synthesized by a one-pot hydrothermal method and the Ni 2 P nanosheets grown on the novel substrate are converted from Ni(OH) 2 via a phosphorization reaction. This hybrid composite combines the 3D porous structure of Ni sponge and high capacity of Ni 2 P nanosheets, which exhibits lightweight, flexible and highly-conductive properties, resulting in an excellent specific capacity of 430.3 mAh g −1 at a current density of 1 A g −1 and remaining as high as 77.0% capacity even at 40 A g −1 . More importantly, the Ni 2 P@Ni sponge//C cell exhibits the maximum energy density of 182.1 W h kg −1 at a power density of 205 W kg −1 along with superior capacity retention of 85.2% after 3000 cycles. It is suggested that the Ni 2 P nanosheet@ Ni sponge composite is a promising electrode material for high-rate batteries. [ABSTRACT FROM AUTHOR]

To meet the design requirements for high-rate battery electrodes, self-supporting hierarchical rGO@Ni nanosheet@Co 3 O 4 nanowire array film with light weight is synthesized via a series of controllable fabrication processes. Due to modifying the highly conductive nickel nanosheets onto the surface of rGO film, the energy storage performance of this hybrid film is enhanced, especially in rate capability. The whole high-rate battery, which is fabricated by using this film as the positive electrode, manifests the maximum energy density of 20.3 Wh kg −1 at a power density of 326 W kg −1 along with excellent capacity retention of 81.4% after 5000 cycles. Therefore, the rGO-Ni-Co 3 O 4 hybrid film is a promising electrode material for flexible long-life cycling high-rate batteries. [ABSTRACT FROM AUTHOR]

Surface conductive engineering on Li 2 S is critical for construction of advanced cathodes of lithium-sulfur batteries. Herein, we construct a high-performance Li 2 S-based composite cathode with the help of three-dimensional reduced graphene oxide (3D-rGO) network and outer carbon coating. Typically, the Li 2 S@C particles are uniformly embedded into 3D-rGO to form a binder-free 3D-rGO-Li 2 S@C cathode by the combination of a liquid solution-evaporation coating and PVP (Polyvinyl Pyrrolidone) carbonization. The 3D-rGO-Li 2 S@C cathode exhibits a high initial discharge capacity of 856 mAh g −1 at 0.1C, superior cycling stability with a capacity of 388.4 mAh g −1 after 200 cycles at 1C, corresponding to a low capacity fading rate. It is demonstrated that the outer conductive coating is effective and necessary for electrochemical enhancement of Li 2 S cathodes by improving electrical conductivity and prohibiting polysulfide from shuttling during cycling. [ABSTRACT FROM AUTHOR]

Metal-doping is considered to be an effective way for construction of advanced semiconducting metal oxides with tailored physicochemical properties. Herein, Mo-doped WO 3 nanowire arrays are rationally fabricated by a sulfate-assisted hydrothermal method. Compared to the pure WO 3 , the optimized Mo-doped WO 3 nanowire arrays exhibit improved electrochromic properties with fast switching speed (3.2 s and 2.6 s for coloration and bleaching, respectively), significant optical modulation (56.7% at 750 nm, 83.0% at 1600 nm and 48.5% at 10 μm), high coloration efficiency (123.5 cm 2 C −1 ) and excellent cycling stability. In addition, as a proof of concept, the Mo-doped WO 3 nanowire arrays are demonstrated with electrochemical energy storage monitored by the electrochromism. This electrode design protocol can provide an alternative way for developing high-performance active materials for bi-functional electrochromic batteries. [ABSTRACT FROM AUTHOR]

A unique MoS 2 -based composite composed of MoS 2 nanosheets wrapped by a conductive polypyrrole (PPY) layer and closely incorporated within reduced graphene oxide (rGO) nanosheets is prepared by all-solution method. As a free-binder electrode for lithium-ion batteries, the ternary electrode delivers an initial discharge capacity of 1428 mAh g −1 , maintains 1070 mAh g −1 after 400 cycles at a current density of 200 mA g −1 , and also exhibits superior rate capacity of 600 mAh g −1 at a high current density of 2000 A g −1 . The enhanced electrochemical performance is attributed to the advantageous combination of the 3D hierarchically rGO skeleton and in-situ formed conductive PPY coating. This design route represents a new direction for high-performance lithium ion batteries and related energy storage application with advanced nanostructured materials. [ABSTRACT FROM AUTHOR]

The construction of advanced cathode materials is indispensable and vital for developing high-performance lithium–sulfur batteries. Herein, we develop a facile in-situ route to synthesize three-dimensional reduced graphene oxide supported Li 2 S/carbon composite (3D-rGO-Li 2 S/C). The Li 2 S/C nanoparticles are intimately anchored on the surface of 3D-rGO forming an integrated 3D porous composite. Due to the improved conductivity and reduced polysulfide dissolution, the 3D-rGO-Li 2 S/C cathode exhibits enhanced electrochemical performances with a high initial capacity of 819 mAh g −1 at 0.1C, as well as good cycling stability with a capacity retention of 415 mAh g −1 after 100 cycles at 1C. The integrated 3D conductive network is responsible for the enhancement of the electrochemical properties by providing fast ion/electron transfer and high mechanical stability. [ABSTRACT FROM AUTHOR]

High-performance electrochromic films with large color contrast and fast switching speed are of great importance for developing advanced smart windows. In this work, crystalline/amorphous WO 3 core/shell (c-WO 3 @a-WO 3 ) nanowire arrays rationally are synthesized by combining hydrothermal and electrodeposition methods. The 1D c-WO 3 @a-WO 3 core/shell hierarchical structures show a synergistic effect for the enhancement of optical modulation, especially in the infrared (IR) region. By optimizing the electrodeposition time of 400 s, the core/shell array exhibits a significant optical modulation (70.3% at 750 nm, 42.0% at 2000 nm and 51.4% at 10 μm), fast switching speed (3.5 s and 4.8 s), high coloration efficiency (43.2 cm 2 C −1 at 750 nm) and excellent cycling performance (68.5% after 3000 cycles). The crystalline/amorphous nanostructured film can provide an alternative way for developing high-performance electrochromic materials. [ABSTRACT FROM AUTHOR]

Scrupulous design and fabrication of advanced anode materials are of great importance for developing high-performance lithium ion batteries. Herein, we report a facile strategy for construction of free-standing and free-binder 3D porous carbon coated MoS 2 /nitrogen-doped graphene (C-MoS 2 /N-G) integrated electrode via a hydrothermal-induced self-assembly process. The preformed carbon coated MoS 2 is strongly anchored on the porous nitrogen-doped graphene aerogel architecture. As an anode for lithium ion batteries, the C-MoS 2 /N-G electrode delivers a high first discharge capacity of 1600 mAh g −1 and maintains 900 mAh g −1 after 500 cycles at a current density of 200 mA g −1 . Impressively, superior high-rate capability is achieved for the C-MoS 2 /N-G with a reversible capacity of 500 mAh g −1 at a high current density of 4000 mA g −1 . Furthermore, the lithium storage mechanism of the obtained integrated electrode is investigated by ex-situ X-ray photoelectron spectroscopy and transmission electron microscopy in detail. [ABSTRACT FROM AUTHOR]

Construction of high-capacity anode is highly important for the development of next-generation high-performance lithium ion batteries (LIBs). Herein we fabricate Si/Ag nanowires/reduced graphene oxide (Si/Ag NWs/rGO) integrated composite film by introducing binary conductive networks (Ag NWs and rGO) into Si active materials with the help of a facile vacuum-filtration method. Active Si nanoparticles are homogeneously encapsulated by binary Ag NWs-rGO conductive network, in which Ag NWs are interwoven among the rGO sheets. The electrochemical properties of the integrated Si/Ag NWs/rGO composite film are thoroughly characterized as anode of LIBs. Compared to the Si/rGO composite film, the integrated Si/Ag NWs/rGO composite film exhibits enhanced electrochemical performances with higher capacity, better high-rate capability and cycling stability (1269 mAh g −1 at 50 mA g −1 up to 50 cycles). The binary conductive network plays a positive role in the enhancement of performance due to its faster ion/electron transfer, and better anti-structure degradation caused by volume expansion during the cycling process. [ABSTRACT FROM AUTHOR]

A novel of Si/porous reduced graphene oxide (rGO) composite is fabricated by steam etching of Si/rGO aerogel. The rGO sheets with nano-holes build a unique three-dimensional porous network and can encapsulate the Si nanoparticles. The porous structure of Si/rGO composite can reduce the transfer distance of Li ions and restrain the aggregation and destruction of Si particles. The in-situ transmission electron microscopy (TEM) observation demonstrates that the porous rGO sheets help the entire electrode to maintain highly conductive and facilitate the lithiation of Si nanoparticles. The composite electrode presents high specific capacity and good cycling stability (1004 mAh g −1 at 50 mA g −1 up to 100 cycles). [ABSTRACT FROM AUTHOR]

A novel 2Li 3 V 2 (PO 4 ) 3 ·LiV 3 O 8 composite with short rod and thin plate shapes is synthesized through sol–gel method followed by hydrothermal and solid–state reaction. LiV 3 O 8 is used as an additive to improve the capacity of Li 3 V 2 (PO 4 ) 3 . In the composite cathode, active impurity phase Li 0.3 V 2 O 5 is also present, which has little impact on the whole electrochemical properties. The 2Li 3 V 2 (PO 4 ) 3 ·LiV 3 O 8 composite delivers a high initial capacity of 162.8 mAh g −1 at a current density of 100 mA g −1 in the voltage range of 2.0–4.3 V. Furthermore, the composite with high crystallinity also shows high electrochemical reversibility and good rate capability. The diffusion coefficient of Li ions in the composite is in the range of 10 −11 –10 −9 cm 2 s −1 obtained from galvanostatic intermittent titration technique. [ABSTRACT FROM AUTHOR]

A novel 0.6Li 3 V 2 (PO 4 ) 3 ·0.4Li–V–O composite cathode material is synthesized by sol-gel method followed by solvothermal and solid state reaction. The morphology and structure of the composite are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photo-electron spectroscopy (XPS). The composite particles are well-crystallized and present uniform nanoplate alike. Except Li 3 V 2 (PO 4 ) 3 phase, LiV 2 O 5 and VO 2 are also present in the composite. The 0.6Li 3 V 2 (PO 4 ) 3 ·0.4Li–V–O electrode delivers a discharge capacity of 149.3 mAh g −1 at 50 mAg −1 between 2.0 V and 4.3 V, and has higher rate property than Li 3 V 2 (PO 4 ) 3 . The diffusion coefficients of Li ions in the composite are in the range of 10 −9.5 − 10 −7.5 cm 2 s −1 obtained from galvanostatic intermittent titration technique (GITT). [ABSTRACT FROM AUTHOR]

Fe 2 O 3 nanospindles assembled with nanoparticles as primary building blocks are directly synthesized by a versatile ionothermal strategy in the choline chloride/urea mixture-based deep eutectic solvent system. The proposed ionothermal protocol is attractive and environmental friendly because choline chloride and urea are both naturally biocompatible compounds. As an anode material for lithium-ion batteries, the resultant Fe 2 O 3 nanospindles show high capacity and good cycle stability (921.7 mAh g −1 at a current density of 200 mA g −1 up to 50 cycles), as well as the excellent rate capability. The good electrochemical performance can be attributed to the nanospindle structure with high sufficient interfacial contact area between the active material and electrolyte, the short diffusion distance of Li ions. The environmentally benign strategy proposed in this study is expected to offer an attractive technique for the ionothermal synthesis of electrochemical energy storage materials. [ABSTRACT FROM AUTHOR]

Fe 2 O 3 nanorods are synthesized by combustion method using alcohol as both solvent and fuel, which is a facile and effective strategy for the large-scale and inexpensive fabrication. The Fe 2 O 3 nanorods are with the well distributed diameters of 20–30 nm and length ranging from 80 to 100 nm. As an anode material for lithium-ion batteries, the Fe 2 O 3 nanorod electrode delivers a high discharge capacity of 761.7 mA h g −1 after 60 cycles at 500 mA g −1 , and 727.2 mA h g −1 at a high current density of 2000 mA g −1 . The good electrochemical performance is attributed to the sufficient contact of active material and electrolyte, large surface area, and short diffusion length of Li + . [ABSTRACT FROM AUTHOR]

Abstract: All the Li metal anode-based batteries suffer from a high propensity to form Li dendrites. To prevent the formation of dendritic lithium on the electrodes, amorphous carbon coatings are deposited onto the surface of metallic lithium foil by magnetron sputtering technique. The electrochemical performances of the amorphous carbon-coated lithium (Li/C) electrodes are investigated by galvanostatic charge/discharge tests, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The compact carbon coatings on the surface of lithium foil can suppress the growth of dendritic lithium during charge–discharge process. The thickness of amorphous carbon coating affects the electrode from two aspects; the thick coating can prevent the formation of dendritic lithium much efficiently, but lead to a large impedance of Li+ transfer. [Copyright &y& Elsevier]