Nitrogen-doped porous carbon coated on MnCo2O4 nanospheres as electrode materials for high-performance asymmetric supercapacitors

Spinel-based nanostructured materials are commonly used as promising electrode materials for super -capacitor applications. The combination of heteroatom-doped carbon material with spinel oxides sub-stantially improves the specific capacitance and cyclic stability. In this work, dopamine-derived nitrogen -doped carbon was coated on spinel phase MnCo2O4 nanospheres using simple solvothermal and calci-nation methods. Surface morphology and the crystalline structure of the prepared MnCo2O4@Nitrogen-doped carbon were confirmed by FESEM and X-ray diffraction. The electrochemical performance of MnCo2O4@Nitrogen-doped carbon electrode material was analyzed by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy techniques. MnCo2O4@nitrogen-doped carbon exhibits the highest specific capacitance of 1200 F/g compared to MnCo2O4 spheres are 726 F/g at 1 A/g and exhibits excellent cyclic stability (capacitance retention of 87% at 7 A/g after 3000 cycles). The enhanced performance of the composite might be benefitted from the synergistic effect between nitrogen-doped carbon on porous MnCo2O4 spheres. Furthermore, an asymmetric supercapacitor device was fabricated by using the optimized composition of MnCo2O4@NC-2 as a positive electrode and ni-trogen, sulfur-doped reduced graphene oxide (NS-rGO) as a negative electrode, respectively. This asymmetric supercapacitor device achieves a maximum energy density of 61.0 Wh/kg at a power density of 2889 W/kg and possesses excellent capacitance retention of 95% after 5000 cycles at 7 A/g.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

In this study, dopamine-derived nitrogen-doped carbon was coated on spinel phase MnCo2O4 nanospheres. The electrochemical performance of the MnCo2O4@Nitrogen-doped carbon electrode material was analyzed, showing high specific capacitance and excellent cyclic stability. The composite's enhanced performance can be attributed to the synergistic effect between nitrogen-doped carbon and porous MnCo2O4 spheres. Moreover, an asymmetric supercapacitor device was fabricated, achieving high energy density and good capacitance retention.