Preparation And Characterization Of Graphene-based Supercapacitor Electrode Materials

Environmental pollution and energy waste often exist in the development and use of fossil energy.Energy conservation is one of the main means to solve such problems.To upgrade the energy saving system and to avoid energy waste to the greatest extent,how to develop efficient energy storage devices is a new challenge facing mankind.Supercapacitors have the advantages of high power density,short charge and discharge time,high energy conversion efficiency and long cycle life.Graphene is a two-dimensional carbon monolayer composed of sp² hybrid carbon,with excellent properties such as light weight,high conductivity and thermal conductivity,high specific surface area and good chemical stability.These excellent properties of the graphene?RGO?electrode materials in electrochemical energy storage and sustainable energy production more attractive,based on the graphene as reinforced material,respectively,the preparation of the graphene reinforced composite aerogel electrodes,electrode and carbon fiber paper discusses the graphene two electrodes to strengthen,the main research results are as follows:?1?The improved Hummers method was used to treat the natural graphite powder and prepare the GO suspension with a concentration of 2 mg/ml.The aerogel electrode materials of RGO were prepared with hydroquinone as the reinforcing and reducing agent.The test results showed that hydroquinone successfully reduced GO.After compressing the membrane electrode at the pressure of 1MPa,the maximum capacitance can reach 83.5 F/g at the current density of 1mA cm^-2.?2?Nano-cellulose fiber?CNF?with a diameter of about 10-50 nm was prepared using bamboo powder as the raw material by means of acid-base alternating treatment and mechanical grinding ultrasonic method.As a hydrophilic material,nano-cellulose fiber can alleviate the hydrophobicity and agglomeration of graphene to a certain extent.?3?Nano-cellulose was introduced into graphene,hydroquinone was used as reducing agent,and self-assembly method was used to mix nano-cellulose into graphene sheets,which not only improved the hydrophilicity of graphene but also alleviated the agglomeration between graphene sheets.A CNF/RGO aerogel electrode with high electrical capacity was prepared.At the current density of 1 mA cm^-2,the electrode capacitance reached 1517 mF cm^-2.At the scanning rate of4mA cm^-2,88.3%capacitance was retained after 2000 cycles.?4?Carbon fiber paper?CFP?is a material with excellent electrical conductivity,which is very suitable for the preparation of supercapacitor electrodes,but its hydrophobicity and low specific capacitance limit its application in the direction of supercapacitors.This paper,by using sulfuric acid?H₂SO₄?and mixed acid,nitric acid?HNO₃?under 60oC chemical treatment of carbon fiber paper,to improve its hydrophilicity.The preparation of composite electrode by suction filtration method was made.?5?The activated carbon fiber paper?A-CFP?obtained from the activation treatment was used as the substrate,and the graphene oxide solution?2 mg/ml?was vacuumized and filtered to the surface of A-CFP,and then reduced to prepare the CFP/RGO binary composite electrode?CR?.After that,it was placed in potassium permanganate solution,and manganese dioxide?MnO₂?was made to grow on the surface of CR by soaking and deposition,so as to prepare CFP/RGO/MnO₂ ternary composite electrode?CRM?.The CRM composite electrode ratio was tested by electrochemical analysis.CR was about 225 mF cm^-22 higher than that of MnO₂,indicating that MnO₂ successfully enhanced the electrochemical properties of CR and that RGO and MnO₂ had a strong synergistic effect,providing a better way for the interface reaction between electrodes and electrolytes.