Fabrication of free-standing NiCo2O4 nanoarrays via a facile modified hydrothermal synthesis method and their applications for lithium ion batteries and high-rate alkaline batteries

Abstract

Self-supported NiCo2O4 nanoflake arrays on nickel foam are prepared by a facile hydrothermal method. The obtained NiCo2O4 nanoflakes with thicknesses of ∼25nm grow vertically to the nickel foam substrate and form an interconnected porous network with pore diameters of 50–500nm. As anode material of LIBs, the NiCo2O4 nanoflake arrays show a high initial coulombic efficiency of 76%, as well as good cycling stability with a capacity of 880mAhg−1 at 0.5Ag−1, and 523mAhg−1 at 1.5Ag−1 after 50 cycles. As the cathode of alkaline batteries, a high capacity of 95mAhg−1 is achieved at 2Ag−1 and 94% retention is maintained after 10,000 cycles. The superior electrochemical performance is mainly due to the unique nanoflake arrays structure with large surface area and shorter diffusion length for mass and charge transport.