Research On Super Activated Carbon Based On Different Precursors

With the rapid development of technology and society,there is an increasing demand for high performance power supplies.In this context,supercapacitors have gained a lot of attention because of their advantages that conventional electrostatic capacitors and batteries do not have.Carbon based electrode materials are currently dominant in industrial applications,and for carbon based materials,optimization of the pore structure is the key to enhance their energy density.Coal,petroleum coke and needle coke are natural carbon sources with high carbon content and can be activated to produce activated carbon materials with adjustable pore structure and high specific surface area,which are important components of supercapacitor electrode materials.In this paper,coal,petroleum coke and needle coke were used as precursors to explore the effects of different carbonization temperatures and activation ratios on their pore structure and energy density by carbonization and chemical activation,with their pore structure as the main focus.The characterization methods of the materials in the experiments mainly include scanning electron microscope test(SEM),Brunner-Emmet-Teller(BET)measurements,resistivity test,etc.The electrochemical test methods of the materials mainly include galvanostatic charge and discharge test(GCD),cyclic voltammetry test(CV)and electrochemical impedance spectroscopy test(EIS),etc.The main contents include.(1)Coal was used as the precursor and pre-carbonated at 400°C,500°C and600°C,and then activated at alkali-coal ratios of 2:1,3:1 and 4:1 respectively,to finally obtain a total of nine samples.After testing,it was found that the sample with the carbonization temperature of 600?and the activation ratio of 4:1 had the largest specific surface area of 2352.08 m~2/g,and also the largest specific capacity of 195.556F/g.(2)Petroleum coke was used as the precursor and pre-carbonized at 600°C,700°C and 800°C,and then activated with alkali-coke ratios of 2:1,3:1 and 4:1respectively,to finally obtain a total of nine samples.In the BET test,the activation difficulty of the material becomes larger as the carbonization temperature increases,and the largest specific surface area is the sample pre-carbonized at 600°C with an activation ratio of 4:1,which can reach 1443.636 m~2/g.In the galvanostatic charge and discharge test,the largest specific capacity is the sample pre-carbonized at 700°C with an activation ratio of 4:1,which can reach a specific capacity of about 241.941F/g.(3)The needle coke as precursor was firstly pre-carbonized at 600?,700?and 800?,and then activated with alkali-coke ratio of 2:1,3:1 and 4:1 respectively,and finally a total of 9 samples were obtained.It was found that their specific capacities decreased with the increase of carbonization temperature and increased with the increase of activation ratio,among which the highest specific capacity was the sample pre-carbonized at 600?with 4:1 activation ratio,which could reach 228.474 F/g.