Preparation and electrochemical properties of polyimide-based carbon nanofibers
In order to develop a sustainable and environmentally friendly supercapacitor energy storage de-vice,a kind of poly(amic acid)(PAA)solution is synthesized by low-temperature condensation reaction us-ing self-made 9,9'-bis[4-(4-nitro-3-hydroxyphenoxy)phenyl]fluorene(BAHPPF)and phthalic anhydride(PMDA)as monomers,and the PAA nanofibers are prepared by electrospinning technology.Then,the rear-rangeable polyimide-based carbon nanofibers(RPICNFs)are prepared by thermal imidization,thermal rear-rangement,and carbonization treatment.The effects of PAA solution concentration and carbonization tempera-ture on the microstructure and electrochemical properties of RPICNFs are studied by using infrared spectrosco-py,scanning electron microscopy,thermogravimetric analysis,X-ray diffraction,Raman spectroscopy,ni-trogen adsorption,and electrochemical performance testing.The experimental results show that when the mass fraction of PAA solution is 25%and the carbonization temperature is 800℃,the as-prepared RPICNF-800-25 sample exhibits a specific surface area of 611.06 m2/g and a pore volume of 0.391 cm3/g.At a current density of 0.5 A/g,the specific capacitance of RPICNF-800-25 is 171.3 F/g,and it still maintains 70%of the initial capacitance at 10 A/g,demonstrating a good rate performance.