Porous Ternary High Performance Supercapacitor Electrode Based on Reduced Graphene Oxide, NiMn2O4, and Polyaniline

This paper reports a novel porous ternary nanohybrid based on NiMn2O4, reduced graphene oxide, and polyaniline (GNMOP) as a superior supercapacitor electrode material. GNMOP was fabricated using a hydrothermal-assisted thermal annealing method, followed by the conductive wrapping of polyaniline through in-situ polymerization. The structure and morphology of the ternary nanohybrid were characterized by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). FTIR, XRD, and XPS confirmed the formation of ternary nanohybrid. SEM and Brunauer-Emmett-Teller (BET) measurement revealed the porous nature of GNMOP, whereas HRTEM analysis demonstrated the wrapping of conducting polyaniline (PANI) on binary composite. Such PANI wrapping enhanced the electrochemical performance of the binary nanocomposite. A specific capacitance of 757 Fg (1) was achieved for GNMOP at a current density of 1 Ag (1), which is much higher than that of the binary nanocomposite and mixed transition metal oxide. In addition, GNMOP exhibited a maximum energy density of 70 Whkg (1) and high capacitance retention of similar to 93% after 2000 cycles. These outstanding electrochemical performances of GNMOP can be attributed to the proper wrapping of conducting polymer and the synergistic impact of distinct components. (C) 2016 Elsevier Ltd. All rights reserved.