Effect of supercritical CO(2) on fabrication of free-standing hierarchical graphene oxide/carbon nanofiber/polypyrrole film and its electrochemical property.

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.