Electrochemical synthesis of porous polyaniline/graphene nanocomposite for advanced supercapacitor applications

Polyaniline (PANI) is a conducting polymer valued for its conductivity, making it attractive for supercapacitor electrodes. Various PANI-based nanocomposites have been developed to enhance the charge storage capability of pristine PANI. However, their performance is limited by insufficient porosity and poor capacitance retention, which hinder efficient ion transport and utilization of electroactive sites. This study introduces a facile electrochemical approach to synthesize porous PANI/graphene nanocomposites using an organic dye, methylene blue (MB) as a pore-forming agent. This method eliminates the need for templates, which complicate the synthesis of porous structures. Graphene was synthesized by electrochemical exfoliation of graphite. The electrochemical polymerization was carried out to synthesize PANI in the presence of graphene and MB. The MB-adsorbed PANI/graphene nanocomposite was deposited on the stainless steel (SS) substrate. The substrate was immersed in ethanol to extract the MB, resulting in the formation of pores in the PANI structure. Structural characterization data confirmed the deposition of the nanocomposite on the SS substrate. Cyclic voltammetry (CV) data showed the porous PANI/graphene achieved an areal capacitance of 20 mF cm −2 at 5 mV s −1 , showing a 163% increase over PANI (7.6 mF cm −2 ). Galvanostatic charge-discharge (GCD) data revealed an energy density of 2.33 μWh cm −2 at a power density of 0.077 mW cm −2 , along with a capacitance retention of 94% after 10 cycles. Electrochemical impedance spectroscopy (EIS) data confirmed the enhanced electrochemical performance of porous PANI/graphene. The results concluded that the proposed method is effective in synthesizing the nanocomposite, which enhances the charge storage capability of PANI.