Dielectric Constant Enhancement with Low Dielectric Loss Growth in Graphene Oxide/Mica/Polypropylene Composites

Polypropylene has been widely used as dielectric material in organic thin-film capacitors due to their high breakdown strength, low dielectric loss and self-healing capability. However, polypropylene’s energy density is relatively low. Increasing the energy density of polypropylene by adding materials with a high dielectric constant is commonly used. Still, it often leads to an increase in dielectric loss, lower dielectric strength and other shortcomings. In this study, a thin 2D platelet of mica/graphene oxide composite material was made from exfoliated mica as a substrate and attached by graphene oxide. The mica/graphene oxide platelets were added to polypropylene to make a plastic dielectric composite. The non-conductive flat inorganic additive can increase the dielectric constant and dielectric strength of the composite without increasing dielectric loss. The tiny mica/graphene oxide platelets can significantly improve the dielectric properties of polypropylene. The results show that by adding a small amount (less than 1 wt%) mica/graphene oxide, the relative dielectric constant of polypropylene can increase to more than 3.7 without causing an increase in dielectric loss and the dielectric strength of polypropylene can also enhance.