Effect of supercritical CO2 on fabrication of free-standing hierarchical graphene oxide/carbon nanofiber/polypyrrole film and its electrochemical property

Abstract

In this paper, supercritical carbon dioxide (SC CO₂) was first reported to help prepare unique flexible free-standing graphene oxide/nanofiber (GC) films. A novel hierarchical superior electrode material with polypyrrole (PPy) deposited on GO/CNF-SC (GC-SC) films was prepared via an in situ polymerization process. Our experimental results indicate that SC CO₂ can not only enlarge the space between GO sheets but also improve the conductivity of the films. The electrochemical measurements show that the as-obtained PPy-coated GC-SC products display remarkably higher capacitive properties than pristine GC/PPy products as electrode materials. Excellent rate performance and stable capacitance retention (89% after 5000 cycles) were observed during the continuous charge–discharge cycles, which verify that SC CO₂ provides a convenient route to the scalable production of hierarchical GO/CNF/PPy films for potential application in supercapacitors.