Design and synthesis of ternary cobalt ferrite/graphene/polyaniline hierarchical nanocomposites for high-performance supercapacitors

A ternary cobalt ferrite/graphene/polyaniline nanocomposite (CGP) is designed and fabricated via a facile two-step approach: cobalt ferrite nanoparticles dispersed on graphene sheets are achieved by a hydrothermal method, followed by coating with polyaniline (PANI) through in situ polymerization process. Electrochemical measurements demonstrate that the specific capacitance of the resulting ternary hybrid (CGP) is up to 1133.3 F g(-1) at a scan rate of 1 mV s(-1) and 767.7 F g(-1) at a current density of 0.1 A g(-1) using a three-electrode system, while 716.4 F g(-1) at a scan rate of 1 mV s(-1) and 392.3 F g(-1) at a current density of 0.1 A g(-1) using a two-electrode system, which are significantly higher than those of pure CoFe2O4, graphene and PANI, or binary CoFe2O4/graphene, CoFe2O4/PANI and graphene/PANI hybrids. In addition, over 96% of the initial capacitance can be retained after repeating test for 5000 cycles, demonstrating a high cycling stability. The extraordinary electrochemical performance of the ternary CGP nanocomposite can be attributed to its well-designed nanostructure and the synergistic effects of the individual components. (C) 2013 Elsevier B.V. All rights reserved.