Metal-organic framework-derived porous MnNi2O4 microflower as an advanced electrode material for high-performance supercapacitors

Abstract

Metal-organic framework (MOF)-derived materials have attracted considerable research interest for electrochemical energy storage and conversion due to their porosity characteristics and relatively simple synthesis routes. Spinel-type ternary transition metal oxide nanomaterials are promising electrode materials in energy-related fields in view of their high reactivity. In this work, flower-like manganese nickelate (MnNi2O4) assembled with porous nanosheets building unite were successfully prepared by using a MOF-derived method. Benefiting from high specific surface area and rich active sites, the as-obtained product exhibited a remarkable electrochemical performance. When tested as an electrode material for supercapacitors, they delivered a high specific capacitance of 2848 F g−1 at 1 A g−1 and a good stability of 93.25% capacitance retention after 5000 cycles at 10 A g−1. To examine their practical application, a hybrid supercapacitor was fabricated using the as-synthesized MnNi2O4 as a positive electrode and active carbon (AC) as a negative electrode. The assembled devices exhibited a high energy density of 142.8 Wh kg−1 at a high power density of 800 W kg−1. When the power density reached 16 kW kg−1, they still delivered a high energy density of 56.8 Wh kg−1. The superior electrochemical performance can be ascribed to the unique microstructures, elemental composition and synergism of flower-like MnNi2O4.