Rational design of sandwiched polyaniline nanotube/layered graphene/polyaniline nanotube papers for high-volumetric supercapacitors

Abstract

The adjustment and optimization of graphene-based electrode structures are crucial to achieve both high volumetric and gravimetric capacitances for portable energy storage devices. Structures of reduced graphene oxide (RGO)-polyaniline (PANI) nanotube hybrid electrodes were facilely regulated and rationally designed by in-situ MnO2 nanowire-templated polymerization. Typically, two different architectures of RGO-PANI composites were obtained by controlling the content of MnO2 nanowires in graphene papers. The assembled symmetric device based on the porous RGO-PANI nanotube papers (0.18mgcm−2, 20.0μm), showed a high gravimetric specific capacitance of 956Fg−1 (against the mass of single electrode) at 1Ag−1 with excellent rate capability of 74.3% from 1Ag−1 to 10Ag−1. In addition, another symmetric device based on the sandwiched polyaniline nanotube/layered graphene/polyaniline nanotube papers (0.80mgcm−2, 4.02μm), provided an ultrahigh volumetric capacitance (722Fcm−3 at 2Acm−3) and a decent gravimetric capacitance (363Fg−1 at 1Ag−1) calculated against the volume and mass of single electrode. With these excellent volumetric and gravimetric capacitive performances, this polyaniline nanotube/layered graphene/polyaniline nanotube supercapacitor holds the potential for high-volumetric and gravimetric-performance energy storages.