Design and Fabrication of Petal-Like NiCo2O4@ NiMoO4 Core/Shell Nanosheet Arrys Electrode for Asymmetric Supercapacitors

The integrated design and fabrication of novel petal-like NiCo2O4@ NiMoO4 core/shell nanosheet arrys electrode through two-step different hydrothermal and annealing process, the unique core-shell structure is beneficial to the diffusion of ion and the transport of charge, furthermore, the integrated structure electrode fully utilizes the synergistic effect of NiCo2O4 as a core material and NiMoO4 as a shell material and exhibits excellent electrochemical performance. The optimized NiCo2O4@ NiMoO4 electrode (4h) delivers 6.91 F cm(-2) and 1974 F g(-1) at 5 mA cm(-2), the capacitance maintains 76% after 5000 cycles at 40 mA cm(-2), Moreover, an asymmetric supercapacitor was assembled by utilizing NiCo2O4@ NiMoO4 electrode (4h) and activated carbon (AC) as the positive and negative electrodes, the viable operating voltage can expand to 1.6 V and energy density can reach 47 Wh kg(-1) at the power density of 0.4 kW kg(-1), the asymmetric supercapacitor shows outstanding cycling stability since the capacitance maintains 87% after 4000 cycles at 5 A g(-1). This prominent electrochemical performance mean NiCo2O4@ NiMoO4 core/shell nanosheet arrays electrode will has a lot of potential applications in energy storage. (C) 2017 The Electrochemical Society. All rights reserved.