Highly efficient and stable negative electrode for asymmetric supercapacitors based on graphene/FeCo2O4 nanocomposite hybrid material

The integration of two-dimensional (2D) reduced graphene oxide (rGO) and binary metal oxide in a single electrode for asymmetric supercapacitors (ASC) is promising for overcoming the challenges driven by increasing energy-storage demands. In present work, we proposed a novel rGO/FeCo2O4 hybrid electrode as a negative electrode for asymmetric supercapacitors (ASC). Briefly, we engineered 3-dimensional nanocomposite materials by decorating FeCo2O4 nanoparticles on rGO nanosheets using facile strategy. Owing to the strong chemical bonding between the FeCo2O4 nanoparticles and rGO nanosheets, as-prepared rGO/FeCo2O4 hybrid electrode shows an ultrahigh specific capacitance of 1710 F/g on the negative potential side. Later, asymmetric supercapacitor was assembled using MnO2 nanowires as positive electrode and rGO/FeCo2O4 hybrid as negative electrode, respectively. The proposed device achieved a maximum specific capacitance of 260 F/g with a specific energy of 67.5 Wh/kg and exhibited excellent cycling performance (96.02% capacity retention after 5000 cycles). Thus, the proposed design of the high-energy ASC is promising for next-generation energy-storage devices being developed for modern consumer applications. (C) 2018 Elsevier Ltd. All rights reserved.