Novel synthesis of ZIF67-derived MnCo2O4 nanotubes using electrospinning and hydrothermal techniques for supercapacitor

Abstract

Bimetallic oxides with multiple redox states and high theoretical capacitances have attracted attention as efficient electroactive material of supercapacitors (SC). MnCo2O4 is applied on SC due to high oxidation potential and multiple oxidation states. One-dimensional nanotube can provide efficient charge-transfer path, large surface area and voids for ions confinements. In this study, it is firstly to synthesize MnCo2O4 nanotubes using electrospinning and hydrothermal techniques for SC. Hydrothermal duration determines redox extents of ZIF67 and Mn precursor, while Mn concentration dominates particle amounts on nanotubes. The optimized MnCo2O4 electrode shows the highest specific capacitance (CF) of 101.9 ​F/g at 20 ​mV/s and the best high-rate performance, due to complete conversion of ZIF67 and KMnO4 as well as well-constructed particle-assembled wall. The symmetric SC presents a maximum energy density of 3.40 ​Wh/kg at 350 ​W/kg, and excellent cycling stability with Coulombic efficiency of 91.2% and CF retention of 91.2% in 5500 cycles.