Method for preparing nano MnO2 composite electrode for high-conductivity super-capacitor

A method for preparing nano MnO2 composite electrode for a high-conductivity super-capacitor includes the steps of taking a multi-walled carbon nanotube, adding the multi-walled carbon nanotube to mixed acid formed by sulfuric acid and nitric acid, wherein the molar ratio of the sulfuric acid and the nitric acid is 3:1, heating the mixed acid to 60 DEG C and stirring the mixed acid in a centrifugal mode, washing the mixed acid repeatedly with deionized water until the PH value of supernatant is 7, drying the multi-walled carbon nanotube for use, preparing electrolyte with the concentration between 0.1g/L and 2g/L, using stainless steel net electrodes as a cathode and an anode, applying direct-current voltage of 0.05-1V/cm2 across the cathode and the anode, depositing for 10-50min, obtaining a stainless steel net absorbing the multi-walled carbon nanotube, preparing a MnSO4 solution or a MnNO3 solution of 0.1mol/L as electrolyte, taking the stainless steel net to prepare an electrode, wherein the electrode serves as a positive pole and a platinum electrode serves as a negative pole, carrying out electrodeposition at a constant current of 0.5-50mA/cm2, keeping the temperature at 90 DEG C, and obtaining the nano MnO2 composite electrode after depositing for 5-30min. The method can conveniently and accurately control current density, electrolysis time, the type, components, the concentration, the PH value and other parameters of the electrolyte, and has the advantages of being simple to operate and low in cost.