Study On The Electrodeposition Preparation And Capacitive Performance Of C/MnO₂ Composite Electrode Materials

Supercapacitors are a new type of environmental energy storage device between batteries and traditional capacacitor.It has attracted tremendous researchers'attention,because of their high power density,excellent reversibility,and cycle life and fast charge and discharge.The supercapacitors mainly consists of electrodes,separators and electrolytes.The electrode plays an important role in the performance of the supercapacitors.However,the traditional electrode manufacturing process is complexed and requires the use of a binder in the electrode manufacturing process.The binder will increase the internal resistance of the electrode,resulting in the loss of energy of the supercapacitor when it works.In this paper,the active material has been electrodeposited on the current collector and fabricated as the supercapacitor,so that the use of the binder in the electrode manufacturing process can be avoided,and the electrodeposition method can be controlled by controlling the deposition conditions during the preparation of the electrode material.For the purpose of the electrode material structure,this paper explores the effects of different deposition conditions on the capacitive properties of the electrode material.The main conclusions are as follows:?1?Manganese dioxide was prepared on a nickel sheet by electrodeposition.The result shows that the nano-amorphous manganese dioxide was prepared by electrodeposition.The electrode material has abundant pores,which increases the specific surface area of the electrode material,and is advantageous to increase the contact area between the manganese dioxide and the electrolyte,thereby improving the manganese dioxide conductivity.The electrode prepared by 15 cycles in the voltage window of-0.5¹.5 V showed excellent electrochemical performance in a 0.5 M Na₂SO₄ electrolyte,and the specific capacitance was as high as 168.66 F/g at the current density of 0.5 mA/cm².?2?CNTs/MnO₂ composite electrode materials were deposited on nickel sheet by electrodeposition.Manganese dioxide nanoflowers were conformally electrodeposited onto carbon nanotube.Such nanostructures effectively decrease the ion diffusion and charge transport resistance in the electrode.The addition of carbon nanotubes can effectively improve the electrochemical performance of electrode materials.The composite electrode material exhibited excellent capacitance performance in 0.5 M Na₂SO₄ electrolyte,and the specific capacitance was as high as 337.37 F/g at a current density of 0.5 mA/cm².The internal resistance of the composite electrode material is also obviously improved because of the addition of carbon nanotubes than the electrodeposited manganese dioxide electrode.?3?Through electrodeposition method,manganese dioxide?RGO and carbon nanotube make up different composites,and the three composites exerted their complementary advantages.Manganese dioxide can be deposited on the CNTs and RGO surfaces to can prevent RGO overlap.The CNTs/RGO/MnO₂ composite electrode material exhibited excellent capacitance performance,the specific capacity can reach 535.01 F/g at the current density of 0.5 mA/cm²,and the capacity still remains at 87.74%after 500 cycles.