Synthesis of a highly efficient 3D graphene–CNT–MnO2–PANI nanocomposite as a binder free electrode material for supercapacitors

Abstract

Graphene based nanocomposites have been investigated intensively, as electrode materials for energy storage applications. In the current work, a graphene–CNT–MnO₂–PANI (GCM@PANI) nanocomposite has been synthesized on 3D graphene grown on nickel foam, as a highly efficient binder free electrode material for supercapacitors. Interestingly, the specific capacitance of the synthesized electrode increases up to the first 1500 charge–discharge cycles, and is thus referred to as an electrode activation process. The activated GCM@PANI nanocomposite electrode exhibits an extraordinary galvanostatic specific capacitance of 3037 F g⁻¹ at a current density of 8 A g⁻¹. The synthesized nanocomposite exhibits an excellent cyclic stability with a capacitance retention of 83% over 12 000 charge–discharge cycles, and a high rate capability by retaining a specific capacitance of 84.6% at a current density of 20 A g⁻¹. The structural and electrochemical analysis of the synthesized nanocomposite suggests that the astonishing electrochemical performance might be attributed to the growth of a novel PANI nanoparticle layer and the synergistic effect of CNT/MnO₂ nanostructures.