Pea-like MoS_(2)@NiS_(1.03)-carbon heterostructured hollow nanofibers for high-performance sodium storage

The rational synergy of chemical composition and spatial nanostructures of electrode materials play important roles in high-performance energy storage devices.Here,we designed pea-like MoS_(2)@NiS_(1.03)-carbon hollow nanofibers using a simple electrospinning and thermal treatment method.The hierarchical hollow nanofiber is composed of a nitrogen-doped carbon-coated NiS_(1.03) tube wall,in which pea-like uniformly discrete MoS_(2) nanoparticles are enclosed.As a sodium-ion battery electrode material,the MoS_(2)@NiS_(1.03)-carbon hollow nanofibers have abundant diphasic heterointerfaces,a conductive network,and appropriate volume variation-buffering spaces,which can facilitate ion diffusion kinetics,shorten the diffusion path of electrons/ion,and buffer volume expansion during Na^(+)insertion/extraction.It shows outstanding rate capacity and long-cycle performance in a sodium-ion battery.This heterogeneous hollow nanoarchitectures designing enlightens an efficacious strategy to boost the capacity and long-life stability of sodium storage performance of electrode materials.

Hierarchically electrospun nanofibers and their applications:A review

Electrospinning is a popular method for generating long and continuous nanofibers due to its simplicity and versatility.However,conventional electrospun products have weak strength and low availability,which restrict their functionality in complex applications.Hierarchical morphology introduces additional and distinctive structural layers onto electrospun fibers.This requires either an extra fabrication step or controlling electrospinning parameters to achieve the desired morphology.Hierarchical morphology can improve the properties of electrospun nanofibers while also mitigating the undesired characteristics.This review discusses the primary and secondary hierarchical structures of electrospun nanomaterials.Hierarchical structures were found to enhance the functionality of nanomaterials and improve pore connectivity and surface areas of electrospun nanofibers.A further advantage is the ability to impart multiple functionalities on nanostructures.With a better understanding of some of the dominant hierarchical structures,nanomaterials applications in drug delivery,tissue engineering,catalysis,and energy devices industries can be improved.

Fabrication and Applications of Multi-Fluidic Electrospinning Multi-Structure Hollow and Core–Shell Nanofibers

Recently,electrospinning(ESP)has been widely used as a synthetic technology to prepare nanofibers with unique properties from various raw materials.The applications of functionalized nanofibers have gradually developed into one of the most exciting topics in the field of materials science.In this review,we focus on the preparation of multi-structure fibrous nanomaterials by means of multi-fluidic ESP and review the applications of multi-structure nanofibers in energy,catalysis,and biology.First,the working principle and process of ESP are introduced;then,we demonstrate how the microfluidic concept is com-bined with the ESP technique to the multi-fluidic ESP technique.Subsequently,the applications of multi-structure nanofibers in energy(Li^(+)/Na^(+)batteries and Li–S batteries),hetero-catalysis,and biology(drug delivery and tissue engineering)are introduced.Finally,challenges and future directions in this emerging field are summarized.

Large-area ultrastrong and stiff aramid nanofiber based layered nanocomposite films

One-dimensional(1D)aramid nanofiber(ANF)based nanocomposite films have drawn increasing attentions in various applications due to their excellent mechanical properties and impressive chemical and thermal stabilities.However,the large-area fabrication of aramid nanocomposite films with ultrastrong mechanical properties under mild conditions remains a great challenge.Here we present a facile superspreading-assisted strategy to produce aramid nanofiber based oriented layered nanocomposites using phase inversion process that occurs at the fully swollen hydrogel surfaces.The nanocomposite films based on ANF,carboxylation carbon tube(CNT–COOH),poly(vinyl alcohol)(PVA),and MXene nanosheet exhibit a tensile strength of up to 870.8±85 MPa,a Young’s modulus of 21.8±2.2 GPa,and outstanding toughness(up to 43.2±4.6 MJ/m^(3)),which are much better than those conventional aramid nanofiber based materials.Electrical conductivity of our nanocomposite films reaches the maximum of about 1100 S/m.The fabulous mechanical properties combination and continuous production capability render our strategy representing a promising direction for the development of high-performance nanocomposites.

Continuous preparation of strong and tough PVA nanocomposite fibers by mechanical stretching-assisted salting-out treatment

Polymer composite fibers with superior properties such as excellent combined strength and toughness and biocompatibility can be used in high-tech applications of braided protective devices and smart wearable,however the research of high-performance polymer composite fiber remains in the infant stage.Here we present a strategy to produce strong and tough anisotropic polymer nanocomposite fibers with orientedly aligned salt rods using mechanical stretching-assisted salting-out treatment.The prepared nanocomposite fibers have a tensile strength of up to 786±2.7 MPa and an elongation at break of 81%,and the anisotropic fibers exhibit good transmission of mechanical vibration in the longitudinal direction with high resolution.During the fabrication process,the salt builds up into oriented rods during the directional salting process,and the polymer is confined to the 150 nm domain between the rods after the solvent is completely evaporated,giving the nanocomposite fibers superior mechanical properties.The presented strategy can be applied to the continuous mass production of nanocomposite fibers and is also generalizable to other polymer nanocomposites,which could extend the applicability of nanocomposite fibers to conditions involving more demanding mechanical loading and mechanical vibration transmission.

Bioinspired Double-stranded Yarn with Alternating Hydrophobic/Hydrophilic Patterns for High-efficiency Fog Collection

Efforts to develop innovative water harvesting strategies offer powerful solutions to alleviate the water crisis,especially in remote and arid areas.Inspired by the hydrophobic/hydrophilic pattern of desert beetles and water self-propulsion property of spider silks,a double-strand hydrophobic PVDF-HFP/hydrophilic PAN nanofibers yarn is proposed by electrospinning and twisting techniques.The double-strand cooperation approach allows for water deposition on hydrophobic PVDF-HFP segment and transport under the asymmetric capillary driving force of hydrophilic PAN segment,thus speeded up the aggregation and growth of droplets.The effects of the composition and the diameter ratio of the two primary yarns were studied and optimized for boosting fog collection performance.The double-strand anisotropic yarn not only provide an effective method for water harvesting,but also hold the potential to inspire innovative design concepts for fog collection materials in challenging environments.

Co3O4 modified Ag/g-C3N4 composite as a bifunctional cathode for lithium-oxygen battery

Rechargeable lithium-oxygen(Li-O2)batteries have appeal to enormous attention because they demonstrate higher energy density than the state-of-the-art Li-ion batteries.Whereas,their practical application is impeded by several challenging problems,such as the low energy round trip efficiencies and the insufficient cycle life,due to the cathode passivation caused by the accumulation of discharge products.Developing efficient catalyst for oxygen reduction and evolution reactions is effective to reduce the overpotentials in Li-O2cells.In our work,we report a Co3O4modified Ag/g-C3N4nanocomposite as a bifunctional cathode catalyst for Li-O2cells.The g-C3N4substrate prevents the accumulation of Ag and Co3O4nanoparticles and the presence of Ag NPs improves the surface area of g-C3N4and electronic conductivity,significantly improving the oxygen reduction/evolution capabilities of Co3O4.Due to a synergetic effect,the Ag/g-C3N4/Co3O4nanocomposite demonstrates a higher catalytic activity than each individual constituent of Co3O4or Ag/g-C3N4for the ORR/OER on as catalysts in Li-O2cells.As a result,the Ag/gC3N4/Co3O4composite shows impressive electrochemical performance in a Li-O2battery,including high discharge capacity,small gap between charge and discharge potential,and high cycling stability.

Designing of anisotropic gradient surfaces for directional liquid transport:Fundamentals,construction,and applications

Many biological surfaces are capable of transporting liquids in a directional manner without energy consumption.Inspired by nature,constructing asymmetric gradient surfaces to achieve desired droplet transport,such as a liquid diode,brings an incredibly valuable and promising area of research with a wide range of applications.Enabled by advances in nano-technology and manufacturing techniques,biomimetics has emerged as a promising avenue for engineering various types of anisotropic material system.Over the past few decades,this approach has yielded significant progressin both fundamental understanding and practical applications.Theoretical studies revealed that the heterogeneous composition and topography mainly govern the wetting mechanisms and dynamics behavior of droplets,including the interdisciplinary aspects of materials,chemistry,and physics.In this review,we provide a concise overview of various biological surfaces that exhibit anisotropic droplet transport.We discussed the theoretical foundations and mechanisms of droplet motion on designed surfaces and reviewed recent research advances in droplet directional transport on designed plane surfaces and Janus membranes.Such liquid-diode materials yield diverse promising applications,involving droplet collection,liquid separation and delivery,functional textiles,and biomedical applications.We also discuss the recent challenges and ongoing approaches to enhance the functionality and application performance of anisotropic materials.

Porous Ti_(3)C_(2)T_(x) MXene nanosheets sandwiched between polyimide fiber mats for electromagnetic interference shielding

With the rapid development of wireless communication technology and electronic devices,the issue of electromagnetic interference(EMI)is becoming increasingly severe.Developing a new and flexible electromagnetic interference shielding material has become a challenging task.Here,a sandwich-structured EMI shielding composite film was prepared using electrospinning and vacuum filtration methods.In this process,a porous MXene was synthesized through a reaction with cobalt acetate and served as the intermediate layer in the composite film to shield electromagnetic waves.The electrospun polyimide(PI)fibers were used as the top and bottom layers of the composite film,which can protect the porous MXene from oxidation.This lightweight and flexible composite film integrates electromagnetic interference shielding and thermal insulation capabilities,showing excellent comprehensive performance.The composite film achieves an EMI shielding effectiveness of 48.8 dB in X-band(8.2–12.4 GHz),and absolute shielding effectiveness of the composite film reached a satisfying 4142.43(dB·cm^(2))/g.Owing to the design of a multi-layer porous structure,the density of the composite film is 0.65 g/cm3.Furthermore,the thermal conductivity of the film is 0.042 W/(m·K)due to the clamping of electrospun PI fibers,showing excellent thermal insulation performance.Additionally,the composite film exhibits excellent high and low-temperature resistance.In summary,this work provides a feasible strategy for preparing a lightweight polymer-based EMI shielding film.

Progress of Fabrication and Applications of Electrospun Hierarchically Porous Nanofibers

In recent years,electrospun nanofibers have attracted great attention for their facile adjustable structure,morphology feature and chemical composition.Especially,significant interest has been devoted to the development of electrospun nanofibers with multiscale pores from micropores and mesopores to macropores,owing to their large specific surface area,hierarchical pore structures,abundant active sites and many other unique properties and applications.This review presents an overview on the design strategies,preparation methods,physical properties and applications of electrospun hierarchical porous nanofibers.At first,electrospinning fabrication of nanofibers with different types of pores including micropores,mesopores,macropores and hierarchical pores are introduced.Then the structures,properties of electrospun porous nanofibers and their applications in several important areas,such as catalysis,energy storage,adsorption and separation,heat insulation and flame retardant,sound absorption and wave absorption,sensor and biomedical are summarized.At last,challenges and potential opportunities of electrospun porous nanofibers in the future are highlighted.

Bioinspired membranes for multi-phase liquid and molecule separation

Water pollution is a serious problem around the world. It causes the lack of clean drinking water and brings risks to human health.Membrane technology has become a competitive candidate to treat the contaminated wastewater due to its high separation efficiency and low energy consumption. In this review, we introduce the recent development of several kinds of bioinspired separation membranes, involving the membrane design and applications. We emphasize the multi-phase liquid separation membranes inspired from nature with special wettability applied for oil/water separation, organic liquids mixture separation, and emulsion separation. After separating multi-phase liquids using these membranes, small molecule pollutants still exist in singlephase liquid. Therefore, we also expand the scope to small molecule-scale separation membranes, such as the nacre-like graphene oxide separation membrane and other nanofiltration membranes. Summary and outlook concerning the future development of separation membranes are also introduced briefly.

Electrospinning Janus Nanofibrous Membrane for Unidirectional Liquid Penetration and Its Applications

Janus membrane with opposite wettability on its two sides has witnessed an explosion of interest in the field of liquid spontaneous and directional transport for their promising prospect.The advances in fabrication technology and natural bionics have brought remarkable progress for the development of Janus materials.Among the exciting progress,the micro/nanofabrication technique of electrospinning shows advantages in constructing thin porous fibrous membrane materials with controllable surface wettability and hierarchical structures.Here,a brief review of bioinspired Janus membrane for unidirectional liquid penetration fabricated by electrospinning is presented,and the underlying scientific mechanism is discussed with an emphasis on the materials design involving asymmetric surface wettability and micro-topology structure.An overview of recent emerging applications is also reviewed,with special attentions to liquid separation,water collection,distillation,and smart textile,etc.As researchers keep to develop more efficient strategies on designing new Janus membrane with higher performances,it has become increasingly important to understand the mechanism of liquid moving dynamics at the asymmetric interface in order to better recognize the scientific limitations currently hindering the field development.At last,the challenges currently faced and possible strategies on developing new Janus membranes for optimization and engineering in the future are proposed.

Anti-vapor-penetration and condensate microdrop self-transport of superhydrophobic oblique nanowire surface under high subcooling

It is well-known that microscale gaps or defects are ubiquitous and can be penetrated by vapor,resulting in the failure of superhydrophobic effect and undesired condensate flooding under high subcooling.Here,we propose and demonstrate that such problem can be solved by the oblique arrangement of nanowires.Such a structure has been demonstrated to own anti-vapor-penetration and microdrop self-transport functions under high subcooling,unaffected by the microscale gaps.This is because vapor molecules can be intercepted by oblique nanowires and preferentially nucleate at near-surface locations,avoiding the penetration of vapor into the microscale gaps.As-formed microdrops can suspend upon the nanowires and have low solid-liquid adhesion.Besides,oblique nanowires can generate asymmetric surface tension and microdrop coalescence can release driving energy,both of which facilitate the microdrop self-removal via sweeping and jumping ways.This new design idea helps develop more advanced condensation mass and heat transfer interfaces.

Furan-based liquid-crystalline small-molecule donor guest improving the photovoltaic performance of organic solar cells with amorphous packing

Introducing liquid-crystalline small-molecule donors(SMDs)into binary systems based on the strong intermolecular interactions of SMDs is a facile and effective strategy to tune the active layer morphology and improve the performance of organic solar cells(OSCs).Contrary to conventional understanding,this research proposes a new strategy for ternary OSCs implicating that"weakly crystalline materials can also optimize the morphology of the active layer and improve the OSCs performance".Herein,we designed and synthesized two liquid-crystalline SMDs,Z1 and Z2,based on benzodifuran(BDF)units.The amorphous Z2-incorporated ternary devices present an unexpectedly improved power conversion efficiency(PCE)>18%with good stability.By contrast,the highly ordered Z1-based ternary devices possess a significantly depressed efficiency.Multiple characterizations reveal that the Z2-based ternary blend films possess improved miscibility and efficient charge transport.This novel strategy for the selection of the third component is significant for the fabrication of high-efficiency ternary OSCs.

An end-capped strategy for crystalline polymer donor to improve the photovoltaic performance of non-fullerene solar cells

The effects of end-capped modifications of a polymer donor with high molecular weight on non-fullerene solar cells are largely ignored,even if the chain-end-functionalized method of conjugated polymers is an effective strategy in modulating polymeric optical-electronic properties.In this study,we design and synthesize an end-capped polymer,PM6TPO,via a reaction with the parent polymer PM6.Meanwhile,the conventional detection methods of X-ray photoelectron spectroscopy(XPS),matrix-assisted laser desorption/ionization time-of-flight(MALDI-TOF),and ^(1)H nuclear magnetic resonance(^(1)H NMR) were replaced by simple solution-based inductively coupled plasma-mass spectrometry(ICP-MS) to evaluate the end-capped efficacy of PM6TPO.By introducing end-capped groups on a high molecular weight polymer donor,we could finely tune the aggregated behavior,strengthen the miscibility between the donor and acceptor without sacrificing the strong aggregated properties,and reduce the non-radiative recombination with a lower energy loss.Therefore,the PM6TPO-based organic solar cell(OSC)realized a higher open-circuit voltage of 0.843 V and PCE of 17.26% than that of the non-end-capped parent polymer,PM6(0.824 V and 16.21%,respectively).This work not only provides a straightforward method for verifying the end-capped efficacy of a high molecular weight polymer but also indicates a new research direction for improving the photovoltaic performance of non-fullerene-based solar cells.

Regularly channeled MXene membranes for ionic and molecular separation

Membrane-based separation technologies,compared with other traditional separation operations such as evaporation,extraction,precipitation and distillation,have the merits of low energy consumption,small land footprint and high efficiency and have,therefore,attracted wide attention in past decades[1,2].Laminar membranes formed by twodimensional(2D)nanosheet stacking showed high flexibility in adjusting the subnanoscale interlayer spacing to allow the unhindered transport of small ions or molecules,demonstrating high separation performance and economic applicability[3].