Fabrication And Assembly Of Supercapacitor Based On MnO₂ Electrode Material

In recent years,traditional energy consumption and environmental pollution have increased,which leads to a huge threat to human society.Therefore,the development of sustainable and renewable energy storage systems is a very urgent task.In addition,alternative energy systems need to meet low-cost and environmentally friendly energy conversion and storage characteristics.Among them,supercapacitors have the characteristics of high power density and excellent cycle stability,which are the current research hotspots.In this paper,Mn O₂-based supercapacitor electrode materials with excellent electrochemical properties are prepared by hydrothermal method,and the dendritic Mn O₂nanostructure and core-shell structure of CoMn-LDH@Mn O₂hybridization are characterized by SEM,TEM,EDS,XPS and other test methods.The microstructure of the nanostructure,the electrochemical performance of the prepared material is tested,and the prepared core-shell CoMn-LDH@Mn O₂hybrid materials are assembled into an asymmetric supercapacitor and electrochemical performance is obtained.The main contents are as follows:（1）Dendrite-like Mn O₂nanostructures on carbon fiber cloth（CFC）have been fabricated through a hydrothermal approach.The electrode materials grown at 125 ^oC show a specific capacitance of 430 F g^-1in 1 M Na₂SO₄electrolyte and 82.75%of the initial capacitance after 10000 cycles.Moreover,an asymmetric supercapacitor is constructed by using Mn O₂structures as positive electrode.The as-assembled device shows an energy density of 20.65 Wh kg^-1at power density of 437.30 W kg^-1and the equipment voltage window can reach 2.45 V.（2）Hybrid CoMn-LDH@Mn O₂products grown on Ni foam have been obtained through a facile hydrothermal route.The as-synthesized products as electrode materials deliver a specific capacitance of 2325.01 F g^-1at 1 A g^-1.An assembled asymmetric supercapacitor using the products as positive electrode shows a maximum energy density of59.73 Wh kg^-1at power density of 1000.09 W kg^-1.（3）The prepared CoMn-LDH@Mn O₂was tested for practical application.The assembled device can drive a small fan for up to 52 s,and the equipment are bent at different angles,and the capacitance of the device hardly changes.This result shows that it has good flexibility characteristics.