In this study, a novel membrane for the separator in a lithium-ion (Li-ion) battery was proposed via a mechanically pressed process with a poly(vinylidene fluoride) (PVDF) nanofiber subject and polyethylene terephthalate (PET) microfiber support. Important physical properties, such as surface morphology, wettability, and heat stability were considered for the PET-reinforced PVDF nanofiber (PRPN) hybrid separator. Images of scanning electron microscopy (SEM) showed that the PRPN hybrid separator had a homogeneous pore size and high porosity. It can wet out in battery electrolytes completely and quickly, satisfying wettability requirements. Moreover, the electrolyte uptake was higher than that of dry-laid and wet-laid nonwovens. For heat stability, no shrink occurred even when the heating temperature reached 135 °C, demonstrating thermal and dimensional stability. Moreover, differential scanning calorimetry (DSC) showed that the PRPN hybrid separator possessed a shutdown temperature of 131 °C, which is the same as conventional separators. Also, the meltdown temperature reached 252 °C, which is higher than the shutdown temperature, and thus can protect against internal cell shorts. The proposed PRPN hybrid separator is a strong candidate material for utilization in Li-ion batteries.

We demonstrate the modulation of physical and mechanical properties by controlling crystallinity in cross-linked poly(vinyl alcohol) (PVA) nanofibers using a simple and straightforward freezing/thawing process.

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We investigated and compared three different methods for synthesizing Ag/PVA nanofibers by effectively dispersing and loading Ag particles onto PVA nanofibers and preventing the detachment of Ag from the nanofibers. The three methods were: (a) the solution reduction method (Method 1) in which the reduction of Ag+ was conducted before electrospinning, resulting in mixing the polymer and the Ag nanoparticles in the electrospinning solution; (b) the immersion method (Method 2) in which electrospun PVA nanofibers were immersed in the Ag+ solution, resulting in loading the Ag particles onto the PVA nanofibers; and (c) the nanofiber reduction method (Method 3) in which the Ag+/PVA solution underwent electrospinning followed by the reduction process with Ag+/PVA nanofibers. All of the electrospun nanofibers had a crosslinked structure that resulted from the chemical reaction of glutaraldehyde with the hydroxyl group of PVA, to prevent dissolution in the aqueous solution. Fourier transform infrared spectra provided evidence of the successful formation of the crosslinked structure of the nanofibers, and x-ray photoelectron spectroscopy and transmission electron microscopy confirmed the loading of Ag nanoparticles onto the nanofibers. The release profiles were investigated by inductively coupled plasma, and the morphology of the nanofibers was observed by scanning electron microscopy. Method 3 had the best performances for loading Ag particles onto the nanofibers and for minimizing the loss of Ag nanoparticles from the nanofibers. These findings identified an effective method for fabricating metal/polymer composite nanofibers, and will allow the expansion of the applications of metal/polymeric composite nanofibers.

The photovoltaic performance of dye-sensitized solar cells (DSSCs) using a photoanode fabricated with graphene incorporated carbon nanofibers with a TiO2 layer on their surfaces is reported.

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