This paper reports an eco-friendly approach for extracting cellulose acetate (CA) from waste cigarette filter to construct a cellulose-based membrane separator for a high-performance lithium-ion battery. A cellulose/poly(vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) nanofiber membrane was prepared by coaxial electrospinning of a cellulose acetate core and PVDF-HFP shell, then hydrolyzed by LiOH. The cellulose-core/PVD-HFP-shell fibrous membrane shows good tensile strength (34.1 MPa), high porosity (66%), excellent thermal stability (to 200 °C), and super electrolyte compatibility (355% electrolyte uptake). It has a lower interfacial resistance (98.5 Ω) and higher ionic conductivity (6.16 mS cm^-1) than those of commercial separators (280.0 Ω and 0.88 mS cm^-1). In addition, the rate capability (138 mAh·g^-1) and cycling performance (75.4% after 100 cycles) are also superior to those of the commercial separators, demonstrating the cellulose-core fibrous membrane to be a promising separator for a high-power and more secure lithium-ion battery.

Polyacrylonitrile (PAN) nanofibers were prepared by electrospinning and they were modified with hydroxylamine to synthesize amidoxime polyacrylonitrile (AOPAN) chelating nanofibers, which were applied to adsorb copper and iron ions. The conversion of the nitrile group in PAN was calculated by the gravimetric method. The structure and surface morphology of the AOPAN nanofiber were characterized by a Fourier transform infrared spectrometer (FT-IR) and a scanning electron microscope (SEM), respectively. The adsorption abilities of Cu²⁺ and Fe³⁺ ions onto the AOPAN nanofiber mats were evaluated. FT-IR spectra showed nitrile groups in the PAN were partly converted into amidoxime groups. SEM examination demonstrated that there were no serious cracks or sign of degradation on the surface of the PAN nanofibers after chemical modification. The adsorption capacities of both copper and iron ions onto the AOPAN nanofiber mats were higher than those into the raw PAN nanofiber mats. The adsorption data of Cu²⁺ and Fe³⁺ ions fitted particularly well with the Langmuir isotherm. The maximal adsorption capacities of Cu²⁺ and Fe³⁺ ions were 215.18 and 221.37 mg/g, respectively.