Hierarchical MnO2 nanosheets coated on MnCo2O4.5 nanoneedles as advanced electrode for high-efficient hybrid supercapacitor

The MnCo2O4.5@MnO2 composite nanomaterial was successfully designed and synthesized via successive hydrothermal and subsequent calcination methods, in which MnO2 nanosheets coated on MnCo2O4.5 nanoneedle arrays were directly grown on Ni foam. Compared with pristine MnCo2O4.5 nanoneedle electrode, MnCo2O4.5@MnO2 composite electrode exhibits a high specific discharge capacitance of 1155 F g(-1) at a current density of 1.43 A g(-1), the capacitance retention of 93.4% after 5000 cycles, and low initial internal resistance of 1.9 Omega. The results reveal that the rational design of MnCo2O4.5@MnO2 electrode with such structure and composition is an effective strategy to improve electrochemical performances of MnCo2O4.5. Due to unique nanostructure and brilliant electrochemical properties of MnCo2O4.5@MnO2 electrode, the fabricated hybrid supercapacitor based on MnCo2O4.5@MnO2 positive electrode and activated carbon negative electrode delivers the wide operating voltage window of 1.6 V, a capacitance retention of 87.8% after 8000 continuous charge-discharge cycles at a current density of 1.33 A g(-1), the maximum energy density of 40.8 Wh kg(-1) at a power density of 263.9 W kg(-1), and highest power density of 1336.6 W kg(-1) to achieve an energy density of 24.4 Wh kg(-1). Herein, the designed MnCo2O4.5@MnO2 composite is a distinguished candidate material for hybrid supercapacitor.

Automated summary

The MnCo2O4.5@MnO2 composite nanomaterial was successfully synthesized via hydrothermal and calcination methods, showing improved electrochemical performance and cycling stability in supercapacitors.