Construction of hierarchical sea urchin-like manganese substituted nickel cobaltite@tricobalt tetraoxide core-shell microspheres on nickel foam as binder-free electrodes for high performance supercapacitors

Construction of binder-free electrodes with hierarchical core-shell nanostructures is considered to be an effective route to promote the electrochemical performance of supercapacitors. In this work, the porous Ni0.5Mn0.5Co2O4 nanoflowers anchored on nickel foam are utilized as framework for further growing Co3O4 nanowires, resulting in the hierarchical sea urchin-like Ni-0.5Mn0.5Co2O4@Co3O4 core-shell micro spheres on nickel foam. Owing to the advantages brought by unique porous architecture and synergistic effect of the multi-component composites, the as-prepared electrode exhibits a high specific capacitance (931 F/g at 1 A/g), excellent rate performance (77% capacitance retention at 20 A/g) and outstanding cycle stability (92% retention over 5000 cycles at 5 A/g). Additionally, the assembled Ni0.5Mn0.5Co2O4@Co3O4//AC (activated carbon) asymmetric supercapacitor achieves a high energy density (50 Wh/kg at 750 W/kg) and long durability (88% retention after 5000 cycles). (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

The construction of binder-free electrodes with hierarchical core-shell nanostructures has been shown to be an effective way to enhance the electrochemical performance of supercapacitors. The electrode prepared in this work exhibited high specific capacitance, excellent rate performance, and outstanding cycle stability due to the advantages brought by unique porous architecture and synergistic effect of the multi-component composites. Additionally, the assembled asymmetric supercapacitor achieved high energy density and long durability.