Effect of graphitization temperature on structure and electrical conductivity of poly-acrylonitrile based carbon fibers

Carbon fibers (CF) with perfect graphitic crystallographic ordering is highly desirable for numerous applications such as carbon interconnects, as electrode material for lithium ion battery, in composites and as hydrogen storage material. In the present manuscript, we report about the effect of graphitization temperature on the crystallinity and electrical conductivity of Poly-acrylonitrile based CF. The change in the crystallinity of graphitized fibers has been explored by using High resolution transmission electron microscopy, X-ray diffractometry, Raman spectroscopy and X-ray photoelectron spectroscopy. Upon graphitization at 1800 degrees C and 2200 degrees C both the in-plane crystallinity (L-a) and out of plane crystallinity (L-c) are found to monotonically increase. The observed spectral features in the Raman spectra have been correlated with graphitic order achieved. The electrical conductivity monotonically increases from 5.32 S/cm to 51.01 S/cm and 75.91 S/cm for PAN fibers graphitized at 1000 degrees C, 1800 degrees C and 2200 degrees C respectively making it one of the promising material for electrical applications.