Influence of Bulk Graphite Density on Electrical Conductivity

Abstract Electrical conductivity of bulk graphite was investigated as a function of its volume density and temperature. The bulk graphite was prepared from pressing natural graphite powders obtained from two different conditions: i) without any treatment and ii) with 24 hr of ultrasonic treatment. Powders from each condition were consolidated using an isobaric press of different pressures, including 5, 10, 20, 30, 40 and 50 MPa. Ultrasonic treatment helped to exfoliate graphene from its parent graphite which enhanced the electrical conductivity of the compressed bulk graphite. Scanning electron microscopy (SEM) and UV-Vis spectroscopy confirmed that multilayer graphenes and nanographite were obtained after the sonication. Raman spectroscopy was also used to investigate the graphitic characteristics of sonicated graphite. The bulk graphite of 50 MPa consolidation from the sonicated powders offered the highest electrical conductivity which was due to its highest density as well as a combination of multilayer graphene. Effect of temperature on the electrical conductivity was discussed. The conductivity increases when increasing the temperature.