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A high-performance proton exchange membrane was successfully prepared by incorporating an interconnected PMIA nanofiber@ZIF-8 network (ZHNFs) into Nafion solution, in which the unique ZHNFs were fabricated via in-situ growth of ZIF-67 on the surface of hierarchical PMIA nanofibers (HNFs) with multiscale nanofibers and high hydrophilicity. The hybrid membrane presents an outstanding performance with a peak proton conductivity of 0.277 S cm−1 at 80 °C, 100RH% and a decreased methanol permeability of 1.415 × 10−7 cm2 s−1, implying a promising application in direct methanol fuel cells. The superior performance of the membranes could be due to the interconnected structure, high specific surface area of 122.637 m2 g−1 and active chemical bond of (−N–H) of ZHNFs. Specifically, the 3D interconnected structure of ZHNFs provides consecutive conduction path for protons, ensuring the improvement of proton conductivity. The effective interfacial acid-base pairs (−N–H ... −SO 3 H) formed via the tight interactions between the –N–H bonds in ZHNFs and –SO 3 H groups in Nafion matrix could effectively ameliorate the compatibility of the nanofiber fillers and Nafion matrix, further promoting the methanol barrier of the hybrid membranes. Moreover, the generated acid-base pairs are beneficial for the efficient and rapid proton transfer via providing abundant proton conducting sites. • Interconnected PMIA nanofiber@ZIF-8 network was obtained. • Hierarchical proton-conducting channels and hindered methanol penetration routs were simultaneously achieved. • Proton conductivity was highly of 0.277 S cm−1 at 80 °C, 100 RH%. [ABSTRACT FROM AUTHOR]

Superhydrophobic waterproof-breathable membranes, which possess a huge superiority in multi-functional applications including self-cleaning, anti-icing, anticorrosion and protective clothing, have aroused considerable attention owing to their excellent performance. Herein, the robust superhydrophobic microporous fibrous membranes were efficiently prepared via a facile and environmental-friendly electro-blown spinning (EBS) technique followed by calcination. Compared with hydrophobic pure PTFE fibrous membranes, the bead-like SiO 2 @PTFE nanofiber membranes (BLNFMs) exhibited superhydrophobic surface with the advancing water angle (θ adv ) and the water contact angle (WCA) up to 161° and 155°, respectively. The SiO 2 nanoparticles were introduced as fillers which can alter the pore structure and form the multilevel rough surface. The BLNFMs could maintain superhydrophobic surface even after abrasion for 30 times or exposing to a strong corrosive solution with PH from 0 to 12 for 24 h. Besides, the BLNFMs were endowed with the modest vapor permeability (9.7 kg·m −2 ·d −1 ) and air permeability (7.2 mm·s −1 ) when the concentration of SiO 2 nanoparticles reached to 7.3 wt%. In addition, a potential relationship among θ adv , maximum pore size (d max ) and breathability (effective breathing area) was proposed in order to design the waterproof-breathable membranes with excellent properties. Furthermore, the superhydrophobic membranes with durable self-cleaning property provided the advantages of potential applications in the fields of membrane distillation, versatile protective clothing, etc. [ABSTRACT FROM AUTHOR]

In this study, the MnO 2 & carbon composite porous nanofibers (CPNF) were prepared via electro-blown spinning and in-situ hydrothermal synthesis. The MnO 2 nano-sheets were uniformly growing on carbon skeleton and filling in honeycomb-like carbon porous nanofibers, and the clear CPNFs were formed. The different hydrothermal parameters including the mass ratios of honeycomb-like porous carbon nanofiber and potassium permanganate, hydrothermal times and temperatures were discussed to obtain optimizing reaction conditions. The CPNFs were investigated by scanning electron microscopy (SEM), transmission electron microscope (TEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and low temperature nitrogen adsorption, respectively, and the supercapacitor performance of CPNF was preliminary tested. The discharge capacity was 421.5 F g −1 at 0.5 A g −1 , and it retained ∼81.2% after 3000 cycles at the current densities of 1.0 A g −1 . Moreover, this CPNF owned special structure and a great industrialization potentiality which could realize the applications in absorption and catalyst fields. [ABSTRACT FROM AUTHOR]

The PVA-based carbon nanofibers with honeycomb-like carbon porous structure were successfully prepared by electro-blown spinning (EBS), pretreatment and carbonation processes. PVA was used as the carbonized polymer while PTFE was used as the sacrificial polymer. The carbon nanofibers with various pore sizes and distribution were prepared by varying the amount of PTFE loading in the spinning solution and optimizing carbonized parameters. The honeycomb-like carbon nanofibers were investigated by scanning electron microscopy (SEM), transmission electron microscope (TEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectrum and low temperature nitrogen adsorption. It was found that specific surface area and pore volume could reach 591.33 m 2 g −1 and 0.58 cm 3 /g, respectively, and large amount of micro-, meso- and macro-pores existed in this kind of porous carbon fiber when the PVA/PTFE was 1:15. This porous carbon nanofiber with special structure and high yield may realize the applications in the fields of adsorption, ion exchange, catalyst supports, etc., and the prepared method has a great industrialization potentiality. [ABSTRACT FROM AUTHOR]

Membrane distillation (MD) is an attractive membrane process for seawater and brine water desalination. One of the main obstacles for MD application is the absence of an effective MD membrane with high water permeability and an excellent salt rejection. This work proposes a novel design strategy of hydrophobic/hydrophilic bi-component membranes for MD by electrospinning and calcination. Unlike the conventional dual-layer hydrophobic/hydrophilic membranes, the bi-component membrane developed in this work is composed of multiple layers of hydrophilic polyimide (PI) nanofibers and hydrophobic polytetrafluoroethylene (PTFE) microclusters, which interweave with each other in the entire membrane. The optimal hydrophobic/hydrophilic bi-component membrane #PTFE/PI-2 shows robust three-dimensional (3D) superhydrophobic and self-cleaning properties. It exhibits a highly competitive permeation flux of 42 ± 3 L m−2 h−1 and an excellent salt rejection above 99.9% in a 400-h continuous DCMD operation when the feed solution was synthetic seawater with a NaCl concentration of 3.5 wt% at 60 °C. Moreover, it is able to achieve an outstanding water flux of 40 ± 2 L m−2 h−1 and a salt rejection over 99.9% when the feed solution was brine water with a NaCl concentration of 25 wt%. The high vapor permeability of #PTFE/PI-2 should be attributed to the high membrane porosity, negligible mass transfer resistance of PI nanofibers and more effective water evaporation area on its superhydrophobic surface. Meanwhile, the excellent anti-wetting property should be due to a unique 3D superhydrophobicity constructed by multiple layers of PTFE microclusters. Image 1 • Hydrophobic/hydrophilic bi-component membrane is proposed. • It composes of PTFE microclusters and PI nanofibers. • The resultant membrane exhibits robust 3D superhydrophobicity. • #PTFE/PI-2 shows a water flux of 40 ± 2 L/m2·h and a salt rejection above 99.9% in MD. [ABSTRACT FROM AUTHOR]

In this work, the inorganic-organic nanofibrous composite separators were successfully prepared for Li-ion capacitor (LIC) via wet-laid method using electro-blown spun inorganic alumina (Al 2 O 3) nanofibers and electrospun organic polyimide (PI) nanofibers as components. Benefitting from the synergistic action of fast ions transfer performance and outstanding fire-resistance offered by Al 2 O 3 nanofibers as well as heat-resistance and entangled force derived from PI nanofibers, the novel membranes exhibited excellent film forming property, outstanding flexibility and high ionic conductivity. Moreover, it delivered superior fire-resistance with dimensional stability after burning. It was discovered that the novel membranes prepared with 50 wt% Al 2 O 3 nanofibers showed better ionic conductivity of 2.71 × 10−3 S cm−1 and broader electrochemical stability window of 5.3 V than those of commercial membranes. The LIC assembled with this novel separator reached the energy density of 12.5 Wh kg−1 even at the high power density of 15 kW kg−1. In addition, this LIC presented a high energy density of 57.3 Wh kg−1 at the current density of 0.5 A g−1 and maintained a high cycle stability even after 10,000 cycles. This study provided the design idea and experimental basis for the development of high-performance LIC separator. [ABSTRACT FROM AUTHOR]

Abstract In this study, a novel core-shell structured poly-m-phenyleneisophthalamide@polyvinylidene fluoride (PMIA@PVDF) nanofiber separator was successfully synthesized via facile coaxial electrospinning. The thermal resistance, electrolyte uptake, ion conductivity as well as anodic stability window of the nanofiber separator were synchronously improved to above 260 °C, 753%, 1.7 mS cm−1 and 5.0 V, which resulted in an appealing safety and electrochemical performance. The markedly enhanced performance could be ascribed to the synergistic advantages of the PMIA core and PVDF shell in the homogeneous PMIA@PVDF nanofiber separator. The PMIA core in PMIA@PVDF nanofiber with high melting point and rigidity character acting as stable skeleton strengthened the thermal stability and integrity of the whole separator. Meanwhile, the lyophilic PVDF shell along with the interconnected open pore structure of electrospinning membrane guaranteed the membrane wettability to electrolyte so as to the ion conduction. Most impressively, under high temperature treatments above 180 °C, the PVDF shell could melt and completely occlude the macropores in PMIA@PVDF nanofiber separator to shut down the battery operation without obvious dimensional shrinkage. Thus, the superiorities in electrochemical performance and safety made PMIA@PVDF nanofiber separator a highly qualified separator for high performance lithium ion battery. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Lithium-sulfur battery is one of the most prospective chemistries in secondary energy storage field due to its high energy density and theoretical capacity, but the rapid decay of capacity is still a huge challenge. Herein, we reported an ingenious design of nitrogen doped carbon nanofibers with honeycomb-like porous structure for the cathode of lithium-sulfur battery which can effectively suppress the “shuttle effect”. The special porous material with three dimensional (3D) interconnected pore structure is beneficial to enhance the adsorption of lithium polysulfides and accommodate the volume expansion of active materials. In addition, the doped nitrogen can not only improve the conductivity of cathode, but also form a strong interfacial interaction to trap lithium polysulfides. Therefore, the battery with the cathode exhibited a high reversible discharge capacity of 1093.9 mAh g −1 and good capacity retention of 76.0% after 300 cycles at 0.5C rate. After acidification, the cycling performance of the cathode could achieve upon 300 cycles with a very low decay rate of 0.027% at 0.5C. [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes replacing traditional liquid electrolytes are considered as an important strategy for developing lithium metal batteries with high safety and energy density. However, poor ionic conductivity and weak mechanical performances have greatly limited the development of solid polymer electrolytes. Here, we dispersed inorganic ceramic particles Li 6 · 4 La 3 Zr 1 · 4 Ta 0 · 6 O 12 (LLZTO) in the polyvinylidene fluoride (PVDF) electrospun nanofibers and then introduced them into polyethylene oxide (PEO) polymers to prepare composite electrolytes. The PVDF nanofibers with embedded LLZTO fillers can simultaneously reduce the crystallinity of the PEO polymer and provide a strong framework support for the composite electrolyte, thereby promoting the transmission of lithium ions and improving the lithium dendrite growth inhibition ability of the composite electrolyte. In addition, the uniform dispersion of garnet-type LLZTO active ceramic filler in the PVDF nanofiber membrane can further optimize the migration path of lithium ions. More importantly, the dehydrofluorination of PVDF due to the introduction of LLZTO can enhance the interaction among PVDF, LLZTO and lithium salts, which promotes dissociation of the lithium salt. The ionic conductivity of the composite electrolyte is as high as 9.30 × 10−4 S cm−1 at 50 °C, and the voltage of Li/Li symmetrical battery would not change significantly during 1200 h at 0.3 mA cm−2. Additionally, the composite electrolytes exhibit good electrochemical stability with the capacity retention rate of 96% under 1 C after 500 cycles. These results provide a strategy for the development of next-generation high-safety all-solid-state lithium metal batteries. An all-solid-state composite electrolyte is synthesized, which has superior ion transmission characteristics, mechanical strength and flexibility, bringing excellent long-cycle stability to Li/Li symmetric battery and Li/LiFePO 4 battery. Image 1 • An all-solid-state composite polymer electrolyte are successfully prepared. • Composite polymer electrolyte exhibits excellent mechanical strength and flexibility. • Li/Li batteries and Li/LiFePO 4 batteries assembled with the composite electrolytes have superior long-cycle stability. [ABSTRACT FROM AUTHOR]

A novel tree-like cellulose nanofiber membrane was controllably fabricated via the electrospinning method by adding certain amount of tetra butyl ammonium chloride (TBAC) into the cellulose acetate solution followed by a deacetylation treatment process. The morphological structure, material structure and air filtration performance of both the cellulose and the cellulose acetate tree-like nanofiber membranes were characterized. Water contact angles, mechanical properties, and air filtration properties were also evaluated. The air filtration efficiency of cellulose acetate tree-like nanofiber membrane can reached 99.58%, and the eventually cellulose tree-like membrane still maintain 98.37%. The eventual cellulose tree-like nanofiber membranes exhibited small pore size, excellent hydrophilicity, good solvent resistance and preferable mechanical property. The small average pore size caused by the tree-like structure and the strong resistance to organic solvent can make it a potential candidate for the membrane separation. [ABSTRACT FROM AUTHOR]

In this study, the F-doped poly-m-phenyleneisophthalamide (PMIA) solution was synthesized by low temperature polymerization method and spun to be three-dimensional nanofibrous membranes by electrospinning. The Energy Dispersive X-Ray Spectroscopy and Fourier Transform Infrared Spectroscopy investigations verified that F was successfully doped in PMIA membrane. The X-ray diffraction patterns showed the crystallinity degree of PMIA membrane decreased with the addition of F. The morphology, pore size and aperture distribution tests manifested that the average diameter of F-PMIA fibers became finer and their distribution was more uniform than these of PMIA fibers. The electrolyte uptake, preserving liquid electrolyte, thermal stability and shrinkage resistance of the F-dopoed membrane were also significantly enhanced than that of pure PMIA membrane. The F-PMIA membrane could be acted as matrix to prepare gel polymer electrolyte. Finally, the F-doped PMIA membrane was used in the assembled coin cells to test the properties including the electronic conductivity, battery interfacial characteristics, electrochemical stability windows and cycle performances of battery. The lower electronic conductivity and interfacial resistance, higher electrochemical stability window (5.7 V) of F-doped PMIA membranes were obtained when comparing to the pure PMIA and commercial polyethylene membrane. The cell exhibited high first-cycle discharge capacity with 145 mAh g −1 and excellent cycling stability with good capacity retention of 93.1% and coulombic efficiency of 99.3% after 100 cycles. [ABSTRACT FROM AUTHOR]

Lithium (Li) metal is deemed as a promising anode for next-generation high-energy-density battery. However, the rebellious dendrites growth leads to the low Coulombic efficiency and safety hazards, which has been a key challenge in the application of Li metal anode. Herein, the ZnF 2 /ZnS heterostructures and N-doped carbon decorated porous carbon nanofibers (ZnF 2 /ZnS/NC/PCNFs) are fabricated through the electro-blow spinning (EBS), metal-organic framework (MOF)-assisted method, and carbonization process. And its application performances as coating functional interlayer of lithium metal batteries (LMBs) to suppress the Li dendrites growth are systematically researched. The conductive interconnected skeleton of NC/PCNFs provides convenient electrons/ions transmission channels and reduces local current density. The lithiophilic ZnF 2 and ZnS nanoparticles can trigger similar alloying reaction with Li-ions to guide the uniform Li deposition. In particular, the inbuilt electric field triggered at the interface of ZnF 2 /ZnS heterostructures improves charge transfer and surface reaction kinetics. Combining with these merits, the Li|LiFePO 4 (Li|LFP) cells with ZnF 2 /ZnS/NC/PCNFs deliver an optimal initial discharge capacity of 143.2 mAh g−1 and capacity retention rate of 93.6% after 600 cycles at 1 C. Moreover, the Li|Li symmetric cells show lower overpotential than that without the interlayer. Extraordinarily, the lithium-sulfur (Li|S) cells with ZnF 2 /ZnS/NC/PCNFs also display excellent cycle stability due to the strong captured or adsorbed ability to dissolved lithium polysulfides. All these results reveal that the utilization of the ZnF 2 /ZnS/NC/PCNFs interlayer provides new insight for protecting the Li metal anode and improving the electrochemical properties and safety of LMBs. [Display omitted] • The ZnF 2 /ZnS/NC/PCNFs interlayer was successfully prepared. • The interlayer provided convenient ions/electrons transmission channel. • ZnF 2 /ZnS heterostructures could enhance the charge transfer kinetics. • The interlayer could inhibit the Li dendrites growth for LMBs and absorb lithium polysulfides for Li.|S batteries. [ABSTRACT FROM AUTHOR]

Owing to high energy density, lithium sulfur (Li–S) battery is regarded as one of the most promising candidates for future energy storage. However, "shuttle effect" and sluggish redox kinetics of lithium polysulfides impede its practical application. Herein, a novel g-C 3 N 4 /Co-based MOFs derived chestnut-like superstructure (Co/CNT@DCNS) was prepared to act as the component of interlayer through a low-temperature one-step carbonization strategy. The prepared superstructure was constructed by the strong catalysis of 0D Co nanoparticles, high conductivity of 1D CNTs and excellent polysulfides adsorption of 2D defect C x N y nanosheets, which could not only ensure the rapid electrons/ions transport and fast redox kinetics, but also provide sufficient spaces for accommodating the volume expansion of active materials. Therefore, the cells with the prepared interlayer exhibited stable performances with an initial capacity of 1348.3 mAhg−1 and an extended cycling stability of 0.04% per cycle during the 1000 cycles at 1C. Even at a high sulfur loading of 3.1 mg cm−2, a specific capacity of 691.7 mAh g−1 can be maintained after 500 cycles at 0.5C. This work shares a convenient and safe strategy for the synthesis of multi-dimension, dual-functional and stable superstructure interlayer for advanced Li–S batteries. Image 1 [ABSTRACT FROM AUTHOR]

In this study, a novel MOFs-anchored-nanofiber framework (UiO-66-NH 2 @NFs) is designed via electrospinning. To hybridize with Nafion matrix, UiO-66-NH 2 @NFs/Nafion membranes with acid-base pairs are fabricated. In the framework, sulfonated poly(ether sulfone) (SPES) nanofibers with effective –SO 3 H groups serve as bonding platforms and UiO-66-NH 2 with –NH 2 groups act as co-reinforcement units tethering in nanofibers. As systematically studied and compared in membrane performance, the homogeneous UiO-66-NH 2 @NFs/Nafion membrane with a moderate UiO-66-NH 2 filler amount of 8 wt% present excellent performance on elevating proton conductivity of 0.27 S cm−1 (80 °C, 100% RH) and inhibiting methanol permeability of 7.54 × 10−7 cm2 s−1, respectively. The above superiorities can be attributed to the unique MOFs-anchored-nanofiber framework with balanced acid-base pairs. The interconnected UiO-66-NH 2 @NFs framework with hydrophilic SPES nanofibers and UiO-66-NH 2 offer consecutive proton transfer channels, making protons easily transfer via the hydration channels. Moreover, –NH 2 groups in UiO-66-NH 2 and –SO 3 H groups in matrix interact via acid-base pairs, which synergistically conducts protons via proton hopping channels in the membranes. Meanwhile, the good compatibility of UiO-66-NH 2 @NFs with Nafion matrix resulting from the tight electrostatically interactions between –NH 2 and –SO 3 H groups endow the hybrid membranes with suppressed methanol permeation and strengthened mechanical properties. Image 1 • UiO-66-NH 2 @NFs with acid-base pairs were built as proton-conducting highways. • Hybrid PEMs were prepared by incorporating UiO-66-NH 2 @NFs into Nafion matrix. • Acid-base interaction and consecutive proton conducting channels were well formed. • The hybrid PEMs exhibited high proton conductivity of 0.270 S cm−1 at 80 °C. [ABSTRACT FROM AUTHOR]