Three-dimensional sea urchin-like MnCoO nanoarchitectures on Ni foam towards high-performance asymmetric supercapacitors

To construct supercapacitors (SCs) with high-efficient electrochemical properties, the morphology and structure of applied electrode materials are the key factors. Herein, three-dimensional (3D) sea urchin-like MnCoO nanoarchitectures grown on Ni foam (NF) were successfully synthesized via a simple solvothermal method and subsequent annealing treatment. Electrochemical tests revealed that the area specific capacitances of the MnCoO electrode and the corresponding assembled asymmetric device can achieve 1634 and 522 mF·cm, respectively. When the power density of the assembled asymmetric supercapacitor (ASC) is 2.25 mW·cm, the maximum energy density can reach 0.163 mW·h·cm. After 5500 cycles of long-term stability test, the capacity retention rate maintains 91.7%. The excellent electrochemical performance can be mainly ascribed to the unique nanostructure of the material, which provides a great quantity of electroactive sites for Faraday redox reactions as well as accelerates the process of the ions/electrons transport. This work provides a certain reference value for the preparation of MnCoO electrode with novel structure and excellent electrochemical performance for SCs.