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. (C) 2010 Elsevier Ltd. All rights reserved.