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Abstract 'Corn-on-the-cob' structured ZnS nanoparticles anchored on porous carbon nanofibers (ZnS/PCNFs) were rationally designed and prepared using preoxidized PVA/PTFE nanofibers as porous matrix precursors through subsequent solvothermal and carbonization. The obtained ZnS/PCNFs composite as anode material for lithium ion batteries exhibit a promising cycling performance with high reversible capacity of 718 mAh g−1 at 0.2 A g−1 after 150 cycles and excellent rate capability with discharge capacity of 438 mAh g−1 at 2 A g−1. The prominent battery performance of ZnS/PCNFs electrode might be ascribed to the distinct hybrid structure, where the uniformly arranged nanosized ZnS 'corns' endowed the hybrid with excellent lithium capacitive performance, and the rationally designed PCNFs 'cob' with large specific surface area not only improved the conductivity but also enhanced the diffusion of electrolyte and ion movement within the hybrid. Graphical abstract Unlabelled Image Highlights • Porous carbon nanofibers were introduced as conductive matrices to hybridize with ZnS. • ZnS nanoparticles were uniformly anchored on porous carbon nanofibers with a unique 'corn-on-the-cob' structure. • The composites exhibited exceptional electrochemical performance. [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]

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]

Highlights • A novel electrospun PVDF-HFP/PMIA nanofiber membrane is successfully prepared. • The membrane can be acted as matrix for heat-resistant gel polymer electrolyte. • The separator has outstanding electrolyte uptake, thermal stability and strength. • The separator possesses high ionic conductivity and stable electrochemical window. • The assembled battery shows high safety and excellent electrochemical properties. Abstract In this work, a novel nanofiber composite membrane constituting poly (vinylidene fluoride-co-hexafluoropropylene) / poly-m-phenyleneiso-phthalamide (PVDF-HFP/PMIA) was successfully fabricated through one-step electrospinning technique. The PVDF-HFP/PMIA nanofibers possessed low average diameter and uniform diameter distribution, which were able to be acted as matrix for gel polymer electrolyte. Significantly, the presence of PVDF-HFP endowed PMIA membrane with considerable high electrolyte uptake and porosity, eminent mechanical strength and remarkable thermal shrinkage resistance. Compared with pure PMIA and polyethylene separators, the PVDF-HFP/PMIA separator obtained higher ionic conductivity, lower interfacial resistance and more stable electrochemical window. The Li/LiCoO 2 battery with the prepared separator reflected admirable cycle stability with outstanding first discharge capacity up to 153.8 mAh g−1 at 0.5C rate and superior capacity retention of 88.75% after 100 cycles. [ABSTRACT FROM AUTHOR]

Highlights • A novel hybrid Octaphenyl-POSS/PMIA membrane is successfully prepared. • The separator has outstanding thermal stability and strength. • The separator shows excellent ability to absorb and store liquid electrolyte. • The separator has high ionic conductivity and stable electrochemical window. • The battery presents high safety and excellent electrochemical performance. Abstract In this study, a hybrid Poly-m-phenyleneisophthalamide/Octaphenyl-Polyhedral oligomeric silsesquioxane (PMIA/Octaphenyl-POSS) membrane (HPPS) was fabricated by electrospinning technique and its application performance as lithium-ion battery separators was discussed. The organic-inorganic feature of Octaphenyl-POSS (OPS) endowed admirable compatibility of membrane matrix for the HPPS membranes. The nanofiber membranes with OPS nanoparticles were provided with commendable thermal stability, robust mechanical strength (21.79 MPa), high porosity and electrolyte uptake, which laid a good foundation for improving the safety and cycle performance of the cells with the separator. The lithium-ion battery with the HPPS separator displayed a high ionic conductivity of 1.93 × 10−3 S·cm−1 and a stable electrochemical window of 4.98 V. More significantly, the HPPS nanofiber membrane based Li/LiCoO 2 cell exhibited excellent cycling stability with high first discharge capacity up to 157.9 mAh·g−1 and superior capacity retention of 89.04% after 100 cycles. Therefore, the HPPS separator has extraordinary potential to be used in high-performance lithium-ion battery. [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]