Omnidirectional porous fiber scrolls of polyaniline nanopillars array-N-doped carbon nanofibers for fiber-shaped supercapacitors

Rolled-up fiber scrolls with outer omnidirectional porous and inner hierarchical porous structure have been fabricated as electrodes of fiber-shaped supercapacitors (FSCs) by polymerizing polyaniline (PANi) nanopillars onto hierarchical 3D interconnected porous N-doped carbon nanofibers scrolls (PANi-HCNFs). The as-prepared fiber-shaped PANi-HCNFs electrode materials used for all solid-state FSCs display excellent electrochemical performance with a high specific capacitance of 339.3 F g(-1) (85.1 mF cm(-1)) and specific mass energy density of 11.6 Wh kg(-1) (areal energy density of 4.28 mu Wh cm(-2)). Meanwhile, PANi-HCNFs show good cycling stability with capacity retention of 74.2% after 3000 cycles at 0.5 A g(-1). The superior electrochemical performance can be attributed to the combining of PANi nanopillars array on the 3D interconnected conducting network with the outer omnidirectional porous and inner hierarchical porous composite structure. This unique composite structure can provide high specific surface area, enabling the effective transport of electrolyte to the inner region of the composite fiber. The backbones of N-doped carbon nanofibers form abundant interconnected conductive network and offer multiple electronic transfer paths. Meanwhile, introducing nanostructured PANi nanopillars array into the carbon matrix can improve higher energy density and provide better cycling stability. (C) 2017 Elsevier Ltd. All rights reserved.