A thermostability gel polymer electrolyte with electrospun nanofiber separator of organic F-doped poly-m-phenyleneisophthalamide for lithium-ion battery

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.