Core-sheath heterostructure of MnCo2O4 nanowires wrapped by NiCo-layered double hydroxide as cathode material for high-performance quasi-solid-state asymmetric supercapacitors

Core-sheath heterostructures composed of MnCo2O4 nanowires wrapped by nanosheets of NiCo-layered double hydroxide (NiCo-LDH) have been obtained on nickel foam (NF) substrate (MnCo2O4@NiCo-LDH/NF). In which, the MnCo2O4 nanowires play role as core structure, while interconnected NiCo-LDH nanosheets acts as the sheath material. The fabrication is achieved by coupling hydrothermal preparation with electrochemical deposition. This heterostructure combines the advantages of interconnection among NiCo-LDH nanosheets, the high conductivity of MnCo2O4, with excellent mechanical strength and 3D open structure of NF. Benefiting from the core-sheath heterostructures and the interaction among these multi-component, when the MnCo2O4@NiCo-LDH/NF composite is utilized as cathode material for supercapacitors, it delivers a superior specific capacitance of 4555.0 F g(-1) at a current density of 1 A g(-1) and maintains a capacitance of 78.7% after 5000 successive charging-discharging cycles using 6M KOH aqueous as electrolyte. In addition, the composite has been used as electrode for assembling the MnCo2O4@NiCo-LDH/NF//AC quasi-solid-state asymmetric supercapacitor (ASC) using active carbon (AC) as counter electrode. Such an ASC exhibits an outstanding energy density of 21.3 W h kg(-1) at a power density of 160.0 W kg(-1) and can light up the green LED indicator for more than 30 min, showing promising prospect for practical applications. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

In this study, core-sheath heterostructures composed of MnCo2O4 nanowires wrapped by nanosheets of NiCo-layered double hydroxide (NiCo-LDH) were successfully obtained. The fabricated composite exhibited high specific capacitance, excellent cycling stability, and promising energy density, making it a potential candidate for practical applications in supercapacitors and asymmetric supercapacitors.