Facile Hydrothermal Synthesis of Binder-Free Hexagonal MnO2 Nanoparticles for a High-Performance Supercapacitor's Electrode Material

Manganese dioxide (MnO2)-based nanostructures are promising electrode materials for supercapacitors (SCs) due to their low cost, eco-friendly nature, and high theoretical capacitance. However, the conductivity of MnO2 is poor, which is a big problem when trying to achieve the desired capacitance value. Herein, hexagonal-phase MnO2 nanoparticles (NPs) are directly grown on a 3D conductive carbon cloth (CC) (denoted as MnO2-NPs@CC) as a binder-free electrode through a simple and scalable hydrothermal strategy. The results show that MnO2-NPs@CC with a large specific surface area and high porosity could be employed as a positive electrode material for high-performance SCs. Owing to these attractive properties, the MnO2-NPs@CC electrode delivers a high specific capacitance of 660 F/g at a current density of 2 A/g in 6 M KOH aqueous electrolytes. Moreover, the MnO2-NPs@CC electrode demonstrates excellent cycling stability with high capacitance retention of 92.8% over 10,000 cycles. Such remarkable findings suggest that MnO2-NPs@CC with enhanced electrochemical performance is a favorable electrode material for next-generation high-performance SCs.