Freestanding RGO—Co₃O₄—PPy Composite Films as Electrodes for Supercapacitors

Abstract

Supercapacitors are of great importance for energy storage and have been the subject of intensive research in recent years, in which conductive polymers are used to make flexible and freestanding electrodes. However, their insufficient access to the electrolytes and the low chemical stability of these conductive polymers lead to their poor performance. To solve these issues, a facile method that can be used to synthesize freestanding composite film electrodes of reduced graphene oxide–cobalt oxide–polypyrrole (RGO—Co 3 O 4 —PPy) as supercapacitors is demonstrated. They exhibit a high specific capacitance of 532.8 F g −1 and nearly no degradation after 700 cycles of charging and discharging. The synergistic effect of Co 3 O 4 , RGO, and PPy is responsible for the superior property. The three‐phase composite electrode utilizes the RGO nanosheet as a substrate to provide a large surface area for loading Co 3 O 4 nanoparticles and also to enhance the electron transfer. Furthermore, the deposition of PPy largely reduces the resistivity of RGO—Co 3 O 4 —PPy, and the introduction of Co 3 O 4 nanoparticles significantly improves cycle stability.