Strongly coupled N-doped carbon/Fe3O4/N-doped carbon hierarchical micro/nanostructures for enhanced lithium storage performance

A strong interface coupling is of vital importance to develop metal oxide/carbon nanocomposite anodes for next-generation lithium ion batteries.Herein,a rational N-doped carb on riveting strategy is designed to boost the lithium storage performance of Fe3O4/N-doped carbon tubular structures.Poly pyrrole(PPy)has been used as the precursor for N-doped carbon.N-doped carbon-riveted Fe3O4/N-doped carbon(N-C@Fe3O4@N-C)nanocomposites were obtained by pyrolysis of PPy-coated FeOOH@PPy nanotubes in Ar atmosphere.When tested as an anode for LIBs,the N-C@Fe3O4@N-C displays a high reversible discharge capacity of 675.8 mA h g-1 after 100 cycles at a current density of 100 mA g-1 and very good rate capability(470 mA h g_1 at 2 A g-1),which significantly surpasses the performance of Fe3O4@N-C.TEM analysis reveals that after battery cycling the FeOx particles detached from the carbon fibers for Fe3O4@N-C,while for N-C@Fe3O4@N-C the FeOx particles were still trapped in the carbon matrix,thus preserving good electrical contact.Consequently,the superior performance of N-C@Fe3C)4@N-C is attributed to the synergistic effect between Fe3O4 and N-doped carbon combined with the unique structure properties of the nanocomposites.The strategy reported in this work is expected to be applicable for designing other electrode materials for LIBs.

Laser Synthesis and Microfabrication of Micro/ Nanostructured Materials Toward Energy Conversion and Storage

Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics devices and even for biomedical purposes.In the past decade,laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction,including the laser processing-induced carbon and non-carbon nanomaterials,hierarchical structure construction,patterning,heteroatom doping,sputtering etching,and so on.The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices,such as light–thermal conversion,batteries,supercapacitors,sensor devices,actuators and electrocatalytic electrodes.Here,the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized.An extensive overview on laser-enabled electronic devices for various applications is depicted.With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies,laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.

A review of the techniques for the mold manufacturing of micro/nanostructures for precision glass molding

Micro/nanostructured components play an important role in micro-optics and optical engineering,tribology and surface engineering,and biological and biomedical engineering,among other fields.Precision glass molding technology is the most efficient method of manufacturing micro/nanostructured glass components,the premise of which is meld manufacturing with complementary micro/nanostructures.Numerous mold manufacturing methods have been developed to fabricate extremely small and high-quality micro/nanostructures to satisfy the demands of functional micro/nanostructured glass components for various applications.Moreover,the service performance of the mold should also be carefully considered.This paper reviews a variety of technologies for manufacturing micro/nanostructured molds.The authors begin with an introduction of the extreme requirements of mold materials.The following section provides a detailed survey of the existing micro/nanostructured mold manufacturing techniques and their corresponding mold materials,including nonmechanical and mechanical methods.This paper concludes with a detailed discussion of the authors recent research on nickel-phosphorus(Ni-P)mold manufacturing and its service performance.

Anticorrosion Coatings from Poly(Aniline-co-2-Ethylaniline) Micro/Nanostructures

PANI copolymer micro/nanostructures with different surface wettability were obtained from the chemical oxidation copolymerization of aniline(Ani)with 2-ethyl aniline(EA)at diverse[EA]/[Ani+EA]molar ratios,by employing ammonium persulfate as an oxidant.The results revealed that the poly(aniline-co-2-ethyl aniline)(PANI-EA)copolymer micro/nanostructures exhibited satisfactory anticorrosion performance for carbon steel,and the corrosion protection efficiency increased with the increase of water repellent property.Poly(2-ethyl aniline)(PEA)showed the largest contact angle(CA=145°)and show the best corrosion protection for the carbon steel(h=87.29%).It is found that the superior anticorrosion property of PEA is attributed to its high hydrophobicity,low conductivity and low porosity.

Simple Fabrication of Hierarchical Micro/Nanostructure Superhydrophobic Surface with Stable and Superior Anticorrosion Silicon Steel via Laser Marking Treatment

To improve the weak corrosion resistance of silicon steel to acid solution and alkaline solution with high temperature,a stable hierarchical micro/nanostructure superhydrophobic surface with myriad irregular micro-scale hump and sheet-like nanostructure was successfully prepared on silicon steel by a simple,efficient and facile operation in large-area laser marking treatment.The morphology,composition,wettability of the as-prepared surface were studied.The superhydrophobic performance of the surface was investigated as well.Additionally,the corrosion resistance of the superhydrophobic surface to acidic solutions at room temperature and alkaline solutions at high temperature (80 ℃) was carefully explored.The corrosion resistance mechanism was clarified.Moreover,considering the practical application of the surface in the future,the hardness of the hierarchical micro/nanostructure superhydrophobic surface was studied.The experimental results indicate that the hierarchical micro/nanostructure surface with texture spacing of 100 μm treated at laser scanning speed of 100 mms/ presents superior superhydrophobicity after decreasing surface energy.The contact angle can be as high as 156.6°.Additionally,the superhydrophobic surface provide superior and stable anticorrosive protection for silicon steel in various corrosive environments.More importantly,the prepared structure of the surface shows high hardness,which ensures that the surface of the superhydrophobic surface cannot be destroyed easily.The surface is able to maintain great superhydrophobic performance when it suffers from slight impacting and abrasion.

Superhydrophobic Micro/Nanostructured Copper Mesh with Self-Cleaning Property for E ective Oil/Water Separation

In this work, a simple method was carried out to successfully fabricate superoleophilic and superhydrophobic N-dodecyltrimethoxysilane@tungsten trioxide coated copper mesh. The as-fabricated copper mesh displayed prominent superoleophilicity and superhydrophobicity with a huge water contact angle about 154.39° and oil contact angle near 0° Moreover, the coated copper mesh showed high separation efficiency approximately 99.3%, and huge water flux about 9962.3 L·h^-1·m-2, which could be used to separate various organic solvents/ water mixtures. Furthermore, the coated copper mesh showed favorable stability that the separation efficiency remained above 90% after 10 separation cycles. Benefiting from the excellent photocatalytic degradation ability of tungsten trioxide, the coated copper mesh possessed the self-cleaning capacity. Therefore, the mesh contaminated with lubricating oil could regain superhydrophobic property, and this property of self-cleaning permitted that the fabricated copper mesh could be repeatedly used for oil and water separation.

Hierarchically Micro/Nanostructured Current Collectors Induced by Ultrafast Femtosecond Laser Strategy for High-Performance Lithium-ion Batteries

Commercial Cu and Al current collectors for lithium-ion batteries(LIBs)possess high electrical conductivity,suitable chemical and electrochemical stability.However,the relatively flat surface of traditional current collectors causes weak bonding strength and poor electrochemical contact between current collectors and electrode materials,resulting in potential detachment of active materials and rapid capacity degradation during extended cycling.Here,we report an ultrafast femtosecond laser strategy to manufacture hierarchical micro/nanostructures on commercial Al and Cu foils as current collectors for high-performance LIBs.The hierarchically micro/nanostructured current collectors(HMNCCs)with high surface area and roughness offer strong adhesion to active materials,fast electronic delivery of entire electrodes,significantly improving reversible capacities and cyclic stability of HMNCCs based LIBs.Consequently,LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(NCM523)cathode with Al HMNCC generated a high reversible capacity after 200 cycles(25%higher than that of cathode with Al CC).Besides,graphite anode with Cu HMNCC also maintained prominent reversible capacity even after 600 cycles.Moreover,the full cell assembled by graphite anode with Cu HMNCC and NCM523 cathode with Al HMNCC achieved high reversible capacity and remarkable cycling stability under industrial-grade mass loading.This study provides promising candidate for achieving high-performance LIBs current collectors.

Bioinspired micro/nanostructured surfaces prepared by femtosecond laser direct writing for multi-functional applications

manufacturing of biomimetic micro/nanostructures due to its specific advantages including high precision,simplicity,and compatibility for diverse materials in comparison with other methods(e.g.ion etching,sol-gel process,chemical vapor deposition,template method,and self-assembly).These biomimetic micro/nanostructured surfaces are of significant interest for academic and industrial research due to their wide range of potential applications,including self-cleaning surfaces,oil-water separation,and fog collection.This review presents the inherent relationship between natural organisms,fabrication methods,micro/nanostructures and their potential applications.Thereafter,we throw a list of current fabrication strategies so as to highlight the advantages of FLDW in manufacturing bioinspired microstructured surfaces.Subsequently,we summarize a variety of typical bioinspired designs(e.g.lotus leaf,pitcher plant,rice leaf,butterfly wings,etc)for diverse multifunctional micro/nanostructures through extreme femtosecond laser processing technology.Based on the principle of interfacial chemistry and geometrical optics,we discuss the potential applications of these functional micro/nanostructures and assess the underlying challenges and opportunities in the extreme fabrication of bioinspired micro/nanostructures by FLDW.This review concludes with a follow up and an outlook of femtosecond laser processing in biomimetic domains.

Icephobic performance on the aluminum foil-based micro-/nanostructured surface

The research of superhydrophobic materials has attracted many researchers＇ attention due to its application value and prospects.In order to expand the serviceable range,people have investigated various superhydrophobic materials.The simple and easy preparation method has become the focus for superhydrophobic materials.In this paper,we present a program for preparing a rough surface on an aluminum foil,which possesses excellent hydrophobic properties after the treatment with low surface energy materials at high vacuum.The resulting contact angle is larger than 160° and the droplet cannot freeze on the surface above-10 ℃.Meanwhile,the modified aluminum foil with the thickness of less than 100 μm can be used as an ideal flexible applied material for superhydrophobicity/anti-icing.

Fabrication of Ordered Micro/Nanostructures Using Probe‑Based Force‑Controlled Micromachining System

This paper presents a probe-based force-controlled nanoindentation method to fabricate ordered micro/nanostructures.Both the experimental and finite element simulation approaches are employed to investigate the influence of the interval between the adjacent indentations and the rotation angle of the probe on the formed micro/nanostructures.The non-contacting part between indenter and the sample material and the height of the material pile-up are two competing factors to determine the depth relationship between the adjacent indentations.For the one array indentations,nanostructures with good depth consistency and periodicity can be formed after the depth of the indentation becoming stable,and the variation of the rotation angle results in the large difference between the morphology of the formed nanostructures at the bottom of the one array indentation.In addition,for the indentation arrays,the nanostructures with good consistency and periodicity of the shape and depth can be generated with the spacing greater than 1μm.Finally,Raman tests are also carried out based on the obtained ordered micro/nanostructures with Rhodamine probe molecule.The indentation arrays with a smaller spacing lead to better the enhancement effect of the substrate,which has the potential applications in the fields of biological or chemical molecular detection.

Facile Synthesis of 3D Porous Flower-like ZnO Micro/nanostructure Films and Their Photocatalytic Performance

3D porous flower-like ZnO micro/nanostructure films grown on Ti substrates are synthesized via a very facile electrodeposition technique followed by heat treatment process. The ZnO architecture is assembled with ultra thin sheets, which consist of numbers of nanoparticles and pores, and the size of the nanoparticles can be controlled by adjusting the electrodepo- sition time or calcination temperature. It is worth noting that this synthetic method can provide an effective route for other porous metal oxide nanostructure films. Moreover, the photocatalytic performance shows the porous ZnO is an ideal photocatalyst.

Generating micro/nanostructures on magnesium alloy surface using ultraprecision diamond surface texturing process

The lightness and high strength-to-weight ratio of the magnesium alloy have attracted more interest in various applications.However,micro/nanostructure generation on their surfaces remains a challenge due to the flammability and ignition.Motivated by this,this study proposed a machining process,named the ultraprecision diamond surface texturing process,to machine the micro/nanostructures on magnesium alloy surfaces.Experimental results showed the various microstructures and sawtooth-shaped nanostructures were successfully generated on the AZ31B magnesium alloy surfaces,demonstrating the effectiveness of this proposed machining process.Furthermore,sawtooth-shaped nanostructures had the function of inducing the optical effect and generating different colors on workpiece surfaces.The colorful letter and colorful flower image were clearly viewed on magnesium alloy surfaces.The corresponding cutting force,chip morphology,and tool wear were systematically investigated to understand the machining mechanism of micro/nanostructures on magnesium alloy surfaces.The proposed machining process can further improve the performances of the magnesium alloy and extend its functions to other fields,such as optics.

Extrusion behavior of micro-nanostructured Al-18%Si alloy powders

The extrusion of Al-Si alloy powders with different particle sizes allows manufacture of different products with unique microstructures and therefore with unique mechanical properties. The effects of powder size on the extrusion behavior and process defect of Al-18%Si alloy were studied by means of microscopy (optical, scanning electron) and density determination. The main objective of the work is to demonstrate the influence of the powder material characteristics on final density and quality of bar. The results show that the bigger the powder particles, the better the performance of cold compacting. The surface of alloy bar extruded from big particles has good quality without cracking. While the smaller the powder particles, the higher the density and the better the microstructure and mechanical properties. For practice application, the mixed powders are better than single powder.

Underwater persistent bubble-assisted femtosecond laser ablation for hierarchical micro/nanostructuring

In this study,we demonstrate a technique termed underwater persistent bubble assisted femtosecond laser ablation in liquids(UPB-fs-LAL)that can greatly expand the boundaries of surface micro/nanostructuring through laser ablation because of its capability to create concentric circular macrostructures with millimeter-scale tails on silicon substrates.Long-tailed macrostructures are composed of layered fan-shaped(central angles of 45°–141°)hierarchical micro/nanostructures,which are produced by fan-shaped beams refracted at the mobile bubble interface(.50°light tilt,referred to as the vertical incident direction)during UPB-fs-LAL line-by-line scanning.Marangoni flow generated during UPB-fs-LAL induces bubble movements.Fast scanning(e.g.1mms−1)allows a long bubble movement(as long as 2mm),while slow scanning(e.g.0.1mms−1)prevents bubble movements.When persistent bubbles grow considerably(e.g.hundreds of microns in diameter)due to incubation effects,they become sticky and can cause both gas-phase and liquidphase laser ablation in the central and peripheral regions of the persistent bubbles.This generates low/high/ultrahigh spatial frequency laser-induced periodic surface structures(LSFLs/HSFLs/UHSFLs)with periods of 550–900,100–200,40–100 nm,which produce complex hierarchical surface structures.A period of 40 nm,less than 1/25th of the laser wavelength(1030 nm),is the finest laser-induced periodic surface structures(LIPSS)ever created on silicon.The NIR-MIR reflectance/transmittance of fan-shaped hierarchical structures obtained by UPB-fs-LAL at a small line interval(5μm versus 10μm)is extremely low,due to both their extremely high light trapping capacity and absorbance characteristics,which are results of the structures’additional layers and much finer HSFLs.In the absence of persistent bubbles,only grooves covered with HSFLs with periods larger than 100 nm are produced,illustrating the unique attenuation abilities of laser properties(e.g.repetition rate,energy,incident angle,etc)by persistent bubbles with different curvatures.This research represents a straightforward and cost-effective approach to diversifying the achievable hierarchical micro/nanostructures for a multitude of applications.

Nanostructured Ternary Metal Tungstate-Based Photocatalysts for Environmental Purification and Solar Water Splitting:A Review

Visible-light-responsive ternary metal tungstate(MWO_4) photocatalysts are being increasingly investigated for energy conversion and environmental purification applications owing to their striking features, including low cost,eco-friendliness, and high stability under acidic and oxidative conditions. However, rapid recombination of photoinduced electron–hole pairs and a narrow light response range to the solar spectrum lead to low photocatalytic activity of MWO_4-based materials, thus significantly hampering their wide usage in practice. To enable their widespread practical usage, significant efforts have been devoted, by developing new concepts and innovative strategies. In this review, we aim to provide an integrated overview of the fundamentals and recent progress of MWO_4-based photocatalysts. Furthermore, different strategies, including morphological control, surface modification, heteroatom doping, and heterojunction fabrication, which are employed to promote the photocatalyticactivities of MWO_4-based materials, are systematically summarized and discussed. Finally, existing challenges and a future perspective are also provided to shed light on the development of highly efficient MWO_4-based photocatalysts.

Particle Modeling Based on Interatomic Potential and Crystal Structure: A Multi-Scale Simulation of Elastic-Plastic Deformation of Metallic Material

We formulate a macroscopic particle modeling analysis of metallic materials (aluminum and copper, etc.) based on theoretical energy and atomic geometries derivable from their interatomic potential. In fact, particles in this framework are presenting a large mass composed of huge collection of atoms and are interacting with each other. We can start from cohesive energy of metallic atoms and basic crystalline unit (e.g. face-centered cubic). Then, we can reach to interparticle (macroscopic) potential function which is presented by the analytical equation with terms of exponent of inter-particle distance, like a Lennard-Jones potential usually used in molecular dynamics simulation. Equation of motion for these macroscopic particles has dissipative term and fluctuation term, as well as the conservative term above, in order to express finite temperature condition. First, we determine the parameters needed in macroscopic potential function and check the reproduction of mechanical behavior in elastic regime. By using the present framework, we are able to carry out uniaxial loading simulation of aluminum rod. The method can also reproduce Young’s modulus and Poisson’s ratio as elastic behavior, though the result shows the dependency on division number of particles. Then, we proceed to try to include plasticity in this multi-scale framework. As a result, a realistic curve of stress-strain relation can be obtained for tensile and compressive loading and this new and simple framework of materials modeling has been confirmed to have certain effectiveness to be used in materials simulations. We also assess the effect of the order of loadings in opposite directions including yield and plastic states and find that an irreversible behavior depends on different response of the particle system between tensile and compressive loadings.

Structure of Micro-nano WC-10Co4Cr Coating and Cavitation Erosion Resistance in NaCl Solution

Cavitation erosion （CE） is the predominant cause for the failure of overflow components in fluid machinery. Advanced coatings have provided an effective solution to cavitation erosion due to the rapid development of surface engineering techniques. However, the influence of coating structures on CE resistance has not been sys- tematically studied. To better understand their relationship, micro-nano and conventional WC-10Co4Cr cermet coat- ings are deposited by high velocity oxygen fuel spray- ing（HVOF）, and their microstructures are analyzed by OM, SEM and XRD. Meanwhile, characterizations of mechan- ical and electrochemical properties of the coatings are carried out, as well as the coatings＇ resistance to CE in 3.5 wt % NaC1 solution, and the cavitation mechanisms are explored. Results show that micro-nano WC-10Co4Cr coating possesses dense microstructure, excellent mechanical and electrochemical properties, with very low porosity of 0.26 4-0.07% and extraordinary fracture toughness of 5.58 4-0.51 MPa.m1/2. Moreover, the CE resistance of micro-nano coating is enhanced above 50% than conventional coating at the steady CE period in 3.5 wt % NaC1 solution. The superior CE resistance of micro- nano WC-10Co4Cr coating may originate from the unique micro-nano structure and properties, which can effectively obstruct the formation and propagation of CE crack. Thus,a new method is proposed to enhance the CE resistance of WC-10Co4Cr coating by manipulating the microstructure.

Study of Multi-Function Micro-Plasma Spraying Technology

A multi-functional micro-arc plasma spraying system was developed according to aerodynamics and plasma spray theory. The soft switch IGBT （Insulated Gate Bipolar Transistor） invert technique, micro-computer control technique, convergent-divergent nozzle structure and axial powder feeding techniques have been adopted in the design of the micro-arc plasma spraying system. It is not only characterized by a small volume, a light weight, highly accurate control, high deposition efficiency and high reliability, but also has multi-functions in plasma spraying, welding and quenching. The experimental results showed that the system can produce a supersonic flame at a low power, spray Al2O3 particles at an average speed up to 430 m/s, and make nanostructured AT13 coatings with an average bonding strength of 42.7 MPa. Compared to conventional 9M plasma spraying with a higher power, the coatings with almost the same properties as those by conventional plasma spray can be deposited by multi-functional micro-arc plasma spraying with a lower power plasma arc due to an improved power supply design, spray gun structure and powder feeding method. Moreover, this system is suitable for working with thin parts and undertaking on site repairs, and as a result, the application of plasma spraying will be greatly extended.

Microsized SnS/Few-Layer Graphene Composite with Interconnected Nanosized Building Blocks for Superior Volumetric Lithium and Sodium Storage

To develop anode materials with superior volumetric storage is crucial for practical application of lithium/sodium-ion batteries.Here,we have developed a micro/nanostructured Sn S/few-layer graphene(Sn S/FLG)composite by facile scalable plasma milling.Inside the hybrid,SnS nanoparticles are tightly supported by FLG,forming nanosized primary particles as building blocks and assembling to microsized secondary granules.With this unique micro/nanostructure,the Sn S/FLG composite possesses a high tap density of 1.98 g cm^(-3)and thus ensures a high volumetric storage.The combination of Sn S nanoparticles and FLG nanosheets can not only enhance the overall electrical conductivity and facilitate the ion diffusion greatly,but alleviate the large volume expansion of Sn S effectively and maintain the electrode integrity during cycling.Thus,the densely compacted Sn S/FLG composite exhibits superior volumetric lithium and sodium storage,including high volumetric capacities of 1926.5/1051.4 m Ah cm^(-3)at 0.2 A g^(-1),and high retained capacities of 1754.3/760.3 m Ah cm^(-3)after 500cycles at 1.0 A g^(-1).With superior volumetric storage performance and facile scalable synthesis,the Sn S/FLG composite can be a promising anode for practical batteries application.

Synthesis of Nano-Meter Micro-Porous Ni_xZn_((1-x))Fe_2O_4 by Hydrothermal Method

Nano-meter micro-porous Ni_xZn_((1-x))Fe_2O_4 (x=0,0.5) ferrites were obtained by hydrothermal method. Triethylamine was used as template by differential thermal analysis (DTA). The results of adsorption experiment show that the powder has micro-porous structure. The crystal structure of the powder was studied by X-ray Diffraction (XRD), and the results show that the powder is of spinel structure. The morphology of Ni_xZn_((1-x))Fe_2O_4 (x=0, 0.5) ferrite was studied by TEM, and the results show that Ni_(0.5)Zn_(0.5)Fe_2O_4 and ZnFe_2O_4 ferrite is well-crystal, well-degree of dispersion with little conglomeration because of weak magnetism. The size of the powder is below 50 nm.