Preparation method and application of carbon material/redox electrolyte composite material

[0038] Example 1

[0039] A method for preparing graphene / redox electrolyte composite material includes the following steps: adding 4 g of graphite powder to concentrated sulfuric acid (92 mL) placed in an ice water bath, and stirring; subsequently, adding 9 g of KMnO 4 Carry out the reaction (the reaction temperature is 50℃); add H after the reaction is over 2 O 2 Reduce unreacted substances; obtain graphene aqueous solution after centrifugation and dialysis. Take 10 mL of the prepared graphene aqueous solution (solid content of 8 mg / mL), 10 mL of deionized water and 165 mg of potassium iodide powder, and transfer to a 25 mL polytetrafluoroethylene reactor for hydrothermal reaction to obtain graphene hydrogel. The reaction temperature is 180°C, and the reaction time is 6 hours. The graphene hydrogel was placed in a drying box and dried for 12 hours in a vacuum environment at 60°C. Subsequently, the obtained material was washed with deionized water and dried at 60° C. to obtain

[0040] Example 2

[0041] The graphene / potassium iodide composite material prepared in Example 1 was used as the working electrode (80wt.% graphene, 10wt.% conductive additive, 10wt.% binder mixed uniformly and coated with 316 stainless steel current collector), and platinum sheet was used as the counter Electrode, silver chloride as a reference electrode, at 1M H 2 SO 4 In the electrolyte, the three-electrode system is assembled to test the electrochemical performance of the electrodes. figure 2 It is the cyclic voltammetry curve of the electrode at a scan rate of 0.5mV / s. It has been tested that the electrode has an obvious redox peak at a potential of 0.4V (vs.Ag / AgCl), and the mass specific capacitance is 222F g -1 ,Volume specific capacitance is 290F L -1 . Figure 4 It is the impedance spectrum of the high-density graphene electrode and the graphene / redox electrolyte composite electrode. The graphene / potassium iodide composite material has been tested to have a charge

[0042] Example 3

[0043] The graphene / potassium iodide composite material prepared in Example 1 was prepared as an electrode (80wt.% graphene, 10wt.% conductive additive, 10wt.% binder mixed uniformly and coated with 316 stainless steel current collector), and used as a positive electrode Negative electrode (mass ratio of positive and negative electrode is 1 to 1), and 1M H 2 SO 4 The electrolyte and glass fiber diaphragm are assembled into a super capacitor. Image 6 Is the cyclic volt-ampere curve of the supercapacitor under the voltage window of 0-1.4V. The mass energy density of the supercapacitor is 39Whkg after testing -1 , The volumetric energy density can reach 50.7Wh L -1 .