Facile synthesis of papillae-like polyaniline nanocones on graphene nanosheets for ultracapacitors

Papillae-like polyaniline (PANI) nanocones arrays growing on graphsene nanosheets (GNs) were synthesized in mass at low cost by in situ polymerization with the assistant of ethanol. Scanning electron microscopy and transmission electron microscopy images show that papillae-like PANI nanocones arrays are located uniformly on flexible two-dimensional GNs. Electrochemical properties are tested by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The electrochemical performances of GNs/PANI hybrid are better than those of bare GNs or PANI. GNs/PANI electrode delivered a maximum specific capacitance of 372 F g^?1 at a current density of 0.1 A g^?1 in 1.0 M Na₂SO₄ aqueous solution. And the composite exhibit an excellent cycle life with ~80% specific capacitance retention over 3000 cycles at 1 A g^?1. The GNs/PANI nanocomposites will be one of the most promising flexible electrode materials for high-performance ultracapacitors.