In order to study the effects of conductive graphene fillers on the conductive mechanisms of epoxy-based materials

graphene/epoxy nanocomposites with different filler content were fabricated

and the conductive percolation threshold（1.35%） of graphene/epoxy systems were measured. Moreover

a DC conduction current measurement system was used for measuring the polarization current of neat epoxy and graphene/epoxy composites（0.3% of graphene filler） at different temperature（50

80 and 100 ℃） and under the electric field of 0.24

1

4.4 k V/mm. The results indicate that the decay rate of polarization current of both composites increases with the increase of temperature and electric field. The main conduction mechanism of both composites t

ransforms from ohmic conduction to space charge limited current（SCLC） conduction at a threshold of conduction current electric field（Ethi）

and the Ethi decreases with the increase of temperature. Moreover

the activation energy of conduction current density increases with the addition of graphene fillers

and the activation energy decreases with the increase of electric field. The conduction mechanisms of graphene/epoxy composites under high electric fields are influenced by SCLC and tunneling effect.