Oxidative MnO₂ Template Assisted Electrochemical Fabrication of Graphene/Polypyrrole Supercapacitor Electrodes

Abstract

Improving the morphological structure of active materials is a reliable strategy for the fabrication of highperformance supercapacitor electrodes. In this study, we introduce a feasible approach to constructing the graphene/polypyrrole (PPy) composite film implanted onto the current collector through a two-step electrochemical deposition method utilizing MnO 2 as an intermediary template. The reduced graphene oxide (rGO) hydrogel film is first hydrothermally grown on a carbon cloth (CC) substrate to obtain a porous rGO@CC electrode on which MnO 2 is electrodeposited. Then the as-prepared rGO/MnO 2 @CC electrode is subjected to the electrochemical polymerization of pyrrole, with MnO 2 acting as an oxidizing template to facilitate the oxidative polymerization of pyrrole, ultimately yielding an rGO/ PPy composite film on CC. The PPy synthesized via this methodology exhibits a distinctive interconnected structure, resulting in superior electrochemical performance compared with the electrode with PPy directly electrodeposited on rGO@CC. The optimized electrode achieves an impressive specific capacitance of 583.6 F g −1 at 1 A g −1 and retains 83% of its capacitance at 20 A g −1 , with a capacitance loss of only 9.5% after 5000 charge−discharge cycles. The corresponding all-solid-state supercapacitor could provide a high energy density of 22.5 Wh kg −1 and a power density of 4.6 kW kg −1 , with a capacitance retention of 82.7% after 5000 charge− discharge cycles. Furthermore, the device also demonstrates good flexibility performance upon bending at 90 and 180°. This work presents an innovative method for the preparation of carbon material/conducting polymer electrodes with specific structural characteristics and superior performance.