Polypyrrole thin film on electrochemically modified graphite surface for mechanically stable and high-performance supercapacitor electrodes

A few-layer graphene oxide-based supercapacitor electrode was fabricated via direct and controlled electrochemical exfoliation of graphite in 0.1 M H₂SO₄ electrolyte. The graphite electrode exfoliated for a 5 min reaction shows the presence of a few layers of graphene oxide on the surface and exhibited excellent electrochemical performance with a maximum areal capacitance of 993 mF cm⁻². However, the electrode failed to retain its surface state under continuous charge/discharge cycles due to the subsequent exfoliation of graphene layers from the graphite surface. But, the deposition of a thin polypyrrole layer effectively reinforces the surface states of the electrode with better mechanical stability as well as electrochemical performances. The fabricated graphite/graphene oxide/polypyrrole electrode showed an improved areal capacitance of 1320 mF cm⁻². Moreover, the electrode exhibited ∼83% cyclic stability after 5000 charge/discharge cycles, which is higher than the stability of graphite/graphene oxide electrode (67%).