Hierarchically structured carbon nanofiber-silsesquioxane-polyaniline nanohybrids for flexible supercapacitor electrodes

In this report, in contrast to conventional processes which rely upon non-covalent wrapping, we manipulate the covalent binding of conjugated polymers to carbon nanofibers to synthesize hybrid nanostructures. First, the Friedel-Crafts acylation reaction was utilized to introduce carboxyl groups onto the nanofiber sidewalls. Octa-aminophenylsilsesquioxane was then uniformly covalently attached to the carboxylated nanocarbon (CNF-COOH) through amide linkage. Subsequently, the phenylamino groups on the CNF surface were copolymerized with aniline via chemical oxidative polymerization to create a unique CNF-conjugated polymer hybrid (CNFS-PANI), and a binder-free CNF-based composite paper electrode was generated by vacuum-filtration. Morphology investigations revealed the formation of 3D porous interconnected network structures with loosely stacked hyperbranched PANI nanobundles due to the incorporation of OASQ onto the skeleton of CNFs. Such a flexible CNFS-PANI nanohybrid paper further exhibited excellent electric conductivity (0.31 S cm(-1)) and specific capacitance (167 F g(-1)), which is much higher than that of original CNFs (2.5 F g(-1)), suggesting its potential use as an electrochemical electrode material.