Synthesis of NiCo2O4@MnO2 Core–Shell Arrays for High Performance Energy Storage

Abstract

Smooth NiCo2O4 nanowire@MnO2 nanosheet structure arrays grown on the surface of Ni foam base is synthesized via a simple two-step hydrothermal method. As-synthetic NiCo2O4@MnO2 electrode material shows higher performance of electrochemistry than single-phase NiCo2O4 and MnO2, which presents area capacitance of 877.4 C cm–2 at a current density 1 mA cm–2. This wonderful property could be associated with special core–shell structure, which possesses opening appearance with large active surface area and fabulous approaches of the electrolyte immersion and ion transmission. Further, the as-assembling device with a working voltage window of 1.5 V shows a highest energy density value of 0.64 Wh cm–3 and a highest power density value of 7.47 W cm–3. The device displays long-cycle stability with 75% increased of initial capacity after 8000 cycles. Providing a material used for the new-generation device for energy storing and high power and energy density with long life.