Engineering 3D-interconnected graphene nanoplatelets and polyaniline nanocomposite for high energy density energy storage

Abstract

A high-performance, seaweed-shaped 3D interconnected nanocomposite electrode comprising graphene nanoplatelets (GNP) and polyaniline (PANI) as an electrode material for supercapacitors is synthesized via conventional in-situ chemical oxidative polymerization. This research aims to enhance the electrochemical performance of the GNP/PANI nanocomposite electrode material by manipulating their shape and electroactive characteristics for greater optimization. While seaweed-shaped GNP/PANI nanocomposites have been reported previously, none have demonstrated high electrochemical performance with an optimized 40 wt% of GNP in GNP/PANI nanocomposite. This deficiency is attributed to the lack of 3D well-interconnected nanocomposite formation and the electroactivity of GNP/PANI when compared to individual PANI or GNP in H2SO4 electrolyte.The electrochemical study confirms an upward revision in specific capacitance, from 400 Fg−1 for GNP and 514 Fg−1 for PANI, to 1088 Fg−1 for the GNP/PANI electrode material in an aqueous 1 M H2SO4 electrolyte solution. It is envisioned that formation of such 3D interconnected GNP/PANI nanocomposite contributes in increasing the interplanar and interchain distances in the nanocomposite particularly in GNP layered structure. Additionally, it is observed that the electrochemical impedance parameters, such as charge transfer resistance Rct (0.12 Ω), high response frequency (1.367 Hz), and short relaxation time (τo ∼ 0.73 s) of the GNP/PANI nanocomposite electrode material, demonstrate excellent performance. The seaweed-shaped GNP/PANI nanocomposite exhibits promising potential as an electrode material for next-generation symmetric supercapacitors due to its high specific capacitance, low cost, and ease of fabrication.