Electrical conductivity of ion-doped graphite/polyethersulphone composites

The electrical conductivity of polyethersulphone (PES) insulating polymer was improved by incorporation of electrically conductive graphite and ions. An initial conducting pathway of the PES/graphite composites was formed at lower than 3 wt.% of the filler content. LiCl was found to be an effective dopant for the improvement of the electrical conductivities of the PES/graphite composites. By doping with 0.06 wt.% of LiCl the electrical conductivity was enhanced by two orders of magnitude. The enhancement resulted from intercalation of Li+ ions into interlayer spaces of the graphite. Upon intercalation, an acceptor GIC, Li-GIC, was consequently formed. The stability of the improved electrical conductivities of the composites contributed with doped-ions was assessed. The electrical conductivity of both un-doped and doped graphite/PES composites slightly increased with increasing temperature and slightly decreased by physical ageing. The enhancement of the electrical conductivities by doping ions was stable at the high temperatures.