Jing Yan

Electrospun cellulose acetate/poly(vinylidene fluoride) nanofibrous membrane for polymer lithium-ion batteries

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 (11.1xa0MPa), electrolyte uptake (768.2xa0%), thermal stability (no shrinkage under 80xa0°C without tension), and ionic conductivity (2.61xa0×xa010−3xa0Sxa0cm−1). The Li/GPE/LiCoO2 battery using this GPE exhibits superior cyclic stability and storage performance at room temperature. Its specific capacity reaches up to 204.15xa0mAhxa0g−1, with embedded lithium capacity utilization rate of 74.94xa0%, which is higher than the other lithium-ion batteries with the same cathode material LiCoO2 (about 50xa0%).

Preparation and characterization of tree-like cellulose nanofiber membranes via the electrospinning method

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.

CeF3-Doped Porous Carbon Nanofibers as Sulfur Immobilizers in Cathode Material for High-Performance Lithium–Sulfur Batteries

In this study, the CeF3-doped porous carbon nanofibers (PCNFs), prepared via electroblown spinning technique and carbonization process, are used as sulfur immobilizers in cathodes for lithium-sulfur (Li-S) batteries for the first time. The cathode composed of CeF3-doped PCNFs, carbon nanotubes (CNTs), and S is successfully prepared through the ball-milling and heating method. The formed porous structure in the PCNFs and CNTs facilitates the construction of highly electrically conductive pathways and effectively alleviates volume changes, which can maintain the stability of the cathode structure and make them in close contact between the electrodes. Meanwhile, the intermediate polysulfide dissolved and lost in the electrolyte can also be suppressed because of the hierarchical porous carbon nanofibers and CeF3. The Li-S battery using the cathode can display excellent electrochemical properties and stable capacity retention, presenting an initial discharge capacity of 1395.0 mAh g-1 and retaining a capacity of 901.2 mAh g-1 after 500 cycles at 0.5C. During the rate capability tests of battery, the discharge capacity of Li-S battery with the electrode slowed down from the discharge capacity of 1284.6 mAh g-1 at 0.5C to 1038.6 mAh g-1 at 1C and 819.3 mAh g-1 at 2C, respectively. It is noteworthy that the battery can still endow an outstanding discharge capacity of 1269.73 mAh g-1 with a high retention of 99.2% when the current density returns to 0.5C.

Electro-blown spun PS/PAN fibrous membrane for highly efficient oil/water separation

The preparation of high performance separation membrane is the key technology for developing efficient oil/water separation system. In this paper, hydrophilic/oleophilic Polystyrene (PS)/Polyacrylonitrile (PAN) bi-component membranes were prepared via electro-blown spinning (EBS) technique and exhibited extremely high oil flux. The addition of PAN component significantly enhanced the tensile strength of the PS based fibrous membranes and PS/PAN membrane with the weight ratio of 5:3 achieved a tensile strength of 2.1 MPa which was 3 times higher than pure PS membrane. The PS/PAN membranes demonstrated a high light oil flux up to 18000 l·m-2·h-1 and could remain the oil flux recovery ratio of 94.09 % after 10 cycles. The as-prepared membranes exhibited the superior oil/water separation performance with the separation efficiency higher than 99.5 % and have a great potential to deal with the oily waste water in the near future.

Facile construction of PCNF&CNT composite material by one-step simultaneous carbonization and chemical vapor deposition

Herein, the composite carbon material of porous carbon nanofiber and carbon nanotube is developed via electro-blown spinning and one-step simultaneous carbonization and chemical vapor deposition without injecting every kind of reaction gas in proportion and removing catalyst in secondary processing. The carbon nanotubes are uniformly growing on carbon skeleton which dramatically improve the performances such as specific surface area (from 334.066 to 644.589xa0m2xa0g−1) and electrical conductivity (from 42.22 to 146.20xa0Sxa0cm−1) comparing with porous carbon nanofibers. The different spinning parameters are investigated to optimize parameters, and the porous carbon nanofiber and carbon nanotube are studied and used as electrode for supercapacitors. The results showed that it possesses excellent electrochemical properties, including high specific discharge capacity (216.5xa0Fxa0g−1 at 1.0xa0Axa0g−1) and good cycle performance (retains ~u200998.68% after 5000 cycles). Moreover, the convenient one-step prepared method special throughout pores structure and superior performance provide a novel approach for designing new types of carbon composite materials which also possess potential application prospect in fields of catalyst, adsorption, etc.

Preparation of Polyurethane-Poly (Vinyl Alcohol) / Chitosan Blend Nanofiber Nonwovens by Coelectrospinning

Polyurethane-poly (vinyl alcohol)/chitosan (PU-PVA/CS) blend nanofiber nonwovens were successfully prepared by coelectrospinning in this paper. The morphology, diameter and structure of the electrospun nanomaterials were examined by SEM and FITR, and their mechanical properties were tested. The diameter distribution of the nanofibers was measured by Image-Pro Plus. The results show that the ideal nanofibers with the diameter in 50-350 nm can be obtained with the proper technical parameters of PU and PVA/CS nanofibers as follows: the spinning voltage at 30 kV and 40 kV, the extruding speed at 6 mL/h and 0.5 ml/h, the collecting distance at 150 mm and 200 mm, respectively.

Study on Hydrophilic Finish and Performance of Polypropylene Spun-Bonded Nonwovens

A new kind of polypropylene spun-bonded nonwovens (PSN) with excellent hydrophilic property was developed after finished with S 6237 hydrophilic agent. The infiltration time (IT) and the runoff (RO) were tested to evaluate the hydrophilicity of the finished PSN. The impacts of different agent concentrations, drying temperatures and drying time on hydrophilicity were investigated and PSN before and after finished were compared concerning softness, air penetrability, moisture regain and stretch performance. The results show that the optimum technological condition for the hydrophilicity is agent concentration: 4 %, drying time: 30s and drying temperatures: 120 °C, and the IT and the RO for the first time are 1.82s and 1.8% respectively. Softness and air penetrability of the finished PSN were improved significantly but mechanical performance was merely decrease a little.

Preparation and Properties of Antistatic SMS Composite Nonwovens

A kind of SMS composite nonwovens with excellent antistatic property was developed by mixing the polypropylene resin and the antistatic agent. Mechanical property, air permeability, drapability and antistatic property of the products at different antistatic agent content were analysed. The results show that the antistatic property of SMS composite nonwovens was improved significantly by blending antistatic agent, Although the mechanical property, drapability and permeability is deceased slightly.