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Graphical abstract Highlights • One-dimensional C/Ce-compound (CeF 3 and CeO 2) composite materials were successfully designed. • CeF 3 and CeO 2 nanoparticles were uniformly dispersed in the porous nanofiber framework. • The porous nanofiber skeleton was beneficial to overcome the drawbacks of nanoparticles. Abstract For practical application of Ce material, one-dimensional C/Ce-compound (CeF 3 and CeO 2) composite materials were successfully designed. Carbon skeleton with unique interconnected porous structure and high specific surface area were manufactured by electro-blown spinning method, using polyvinyl pyrrolidone as the carbon precursor and polytetrafluoroethylene as the pore forming agent. CeF 3 and CeO 2 nanoparticles were uniformly doped in PCNF framework by in-situ encapsulation and hydrothermal methods, respectively. The porous nanofiber skeleton was beneficial to overcome the agglomeration and recycling problem of Ce-compound nanoparticles. This designed structure provided a promising strategy to ameliorate nanostructure material, suggesting potential application in catalyst and energy storage system. [ABSTRACT FROM AUTHOR]

Abstract: Eco-friendly tree-like porous carboxyl modified cellulose nanofiber membranes as highly efficient adsorbents for heavy metal ions were fabricated by the electrospinning of cellulose acetate (CA)/tetrabutylammonium chloride (TBAC)/manganese dioxide (MnO2) solution, and subsequent deacetylation treatment to turn CA into cellulose and citric acid modification to graft carboxyl group on the surface of cellulose nanofibers. The addition of TBAC led to the formation of tree-like structure and MnO2 particles were used as pore-forming agents. The effects of pH, initial ion concentrations and contact time on the removal capacity of heavy metal ions were investigated. During the removal process, the abundant carboxyl groups (-COOH) transferred to carboxylate ions (-COO−) which had stronger ion exchange ability to the metal ion adsorption. In addition, the tree-like porous structure supplied large specific surface area and effectively increased the removal capacity. The removal process could reach a plateau in 90 min with the maximum removal amount of 399.14 mg/g. The removal process was also depicted by Langmuir and Freundlich isotherm model. Generally, the tree-like porous structure will have extensive prospects in the fields of filtration, electrochemistry, tissue engineering and so on.Graphical abstract: [ABSTRACT FROM AUTHOR]

Pullulan nanofiber membrane (Pull-NM) was prepared by electrospinning method and its stability in the water was improved by a chemical crosslinking with mixed solution of ethylene glycol diglycidyl ether (EGDE) and ethanol absolute as crosslinking agent. The effect of crosslinked pullulan nanofiber membrane (C-l-Pull-NM) with different process conditions was studied and the excellent crosslinking reaction condition is proved to be 1:70 (EGDE: ethanol absolute) for 24 h. The analytical methods, including SEM, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and differential scanning calorimetry, were used to study morphology, structure, and thermal performance of the nanofiber membrane. In addition, the swelling behavior and tensile were also discussed. The results showed that the water resistance of crosslinked nanofiber membrane had a significant improvement. Furthermore, the maximum water absorption and the strength were reached to about 520 and 192.7%, respectively. [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]

Recently, the multi-level structure materials with some superior performances has attracted broad attentions. In this study, the elastomeric tree-like thermoplastic polyurethane (TPU) nanofiber membranes with multilevel structure were prepared by introducing tetrabutylammonium chloride (TBAC) via one-step electrospinning. The coverage rate and average diameter of the TPU tree-like nanofibers could be controlled by varying the solution concentrations and electrospun parameters. The special multilevel structure with trunk fibers (diameter 300–500 nm) and branch fibers (diameter 20–80 nm) significantly improved crystallinity, hydrophilicity and flexibility performances comparing with pristine TPU nanofibers, and the novel hierarchical elastomeric tree-like nanofiber membrane had a bright future in various potential applications, such as medical, filtration and protective field, etc. [ABSTRACT FROM AUTHOR]

The membranes for gel polymer electrolyte (GPE) for lithium-ion batteries were prepared by electrospinning a blend of poly(vinylidene fluoride) (PVdF) with cellulose acetate (CA). The performances of the prepared membranes and the resulted GPEs were investigated, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), porosity, hydrophilicity, electrolyte uptake, mechanical property, thermal stability, AC impedance measurements, linear sweep voltammetry, and charge-discharge cycle tests. The effect of the ratio of CA to PVdF on the performance of the prepared membranes was considered. It is found that the GPE based on the blended polymer with CA:PVdF =2:8 (in weight) has an outstanding combination property-strength (11.1 MPa), electrolyte uptake (768.2 %), thermal stability (no shrinkage under 80 °C without tension), and ionic conductivity (2.61 × 10 S cm). The Li/GPE/LiCoO battery using this GPE exhibits superior cyclic stability and storage performance at room temperature. Its specific capacity reaches up to 204.15 mAh g, with embedded lithium capacity utilization rate of 74.94 %, which is higher than the other lithium-ion batteries with the same cathode material LiCoO (about 50 %). [ABSTRACT FROM AUTHOR]

• The different fabrication techniques of nanofiber materials are summarized. • The functional action mechanisms of nanofibers for inhibiting Li dendrites are reviewed. • Various protection strategies of nanofiber materials to suppress the Li dendrites growth are summarized. • The challenges and prospects of nanofiber materials for Li anode are discussed. Lithium metal batteries (LMBs) are regarded as one of the most promising candidates for next-generation energy storage systems. However, the uncontrolled dendritic lithium (Li) growth lead to low Coulombic efficiency and security issue, thus limiting the commercial applications of LMBs. Owing to the unique nanostructure characteristics, nanofiber materials offer innovative strategies and opportunities to resolve the tricky challenge. A comprehensive review of the fundamental researches and technological developments of various nanofiber materials for LMBs was presented in this paper. The fabrication techniques of nanofibers and several functional action mechanisms for inhibiting dendritic Li were outlined. Then the different protection technologies of nanofiber materials for LMBs to suppress the Li dendrites growth were summarized, which included modifying separators, introducing functional interlayers and constructing novel composite anodes and current collectors. Meanwhile, the electrochemical performances using different strategies of the overall LMBs were discussed. Finally, the current challenges and prospects of nanofiber materials for Li anode were discussed. These discussions and proposed strategies will enlighten thoughts and offer ways to the practical application of LMBs with excellent electrochemical performances in the future. [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, F-doped tree-like nanofiber structural poly-m-phenyleneisophthalamide (PMIA) membranes are prepared via one-step electrospinning approach and their application performance as separators for lithium-sulfur batteries are discussed. The F-doped PMIA membrane can be regarded as matrix to form gel polymer electrolyte. The F doping endows the PMIA membranes with extraordinary high electrolyte uptake, excellent ability of preserving the liquid electrolyte and forceful chemisorption to polysulfides. And the tree-like structure effectively blocks polysulfides by the physical confinement. The lithium-sulfur cell with the F-doped PMIA separator exhibits high first-cycle discharge capacity of 1222.5 mAh g −1 and excellent cycling stability with good capacity retention of 745.7 mAh g −1 and coulombic efficiency of 97.97% after 800 cycles. The remarkable performance can be ascribed to the suppressed shuttle effects through both the physical trapping of polysulfides by the gel polymer electrolyte based on matrix with F-doped PMIA membrane and the tree-like structure in a working cell. [ABSTRACT FROM AUTHOR]

A smart tree-like nanofiber membrane with pH-responsivity was successfully fabricated by electrospinning poly(vinylidene fluoride)-graft-poly(acrylic acid) (PVDF-g-PAA). X-ray photoelectron spectroscopy, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and Brunauer-Emmett-Teller surface area measurement were employed to study the molecular structure and morphology of membranes. Through realizing protonation and deprotonation in response to the pH of the aqueous media, the as-prepared membrane is able to alter its wettability and conformation, resulting in the switchable surface oil/water wettability in the aqueous media. More importantly, the as-prepared membrane realized on-demand oil/water separation using gravity alone by switching the pH of the medium. Both separations exhibited excellent efficiency and flux which were attributed to the tree-like structure of the membrane. We believed that this smart membrane with such excellent controllable permeation has potential to be used for several applications, such as water purification, oil recovery and some separation systems. [ABSTRACT FROM AUTHOR]