Preparation Of Heteroatom-Doped Porous Carbons For High-Performance Supercapacitors

Supercapacitors have been widely used in industry due to their high energy density and cycle stability.Carbon materials are the most widely used electrode materials for supercapacitors.The traditional method to prepare carbon materials is complicated,hydrophilic and specific surface area is small,so the capacitance performance is not ideal.Heteroatom doping can be considered to improve the wettability and pseudocapacitance of carbon materials.In this paper,heteroatom doped porous carbon materials were prepared by in-situ template method and KOH activated polypyrrole method,respectively.The carbon materials were characterized by various methods,and their electrochemical performances were tested.The relationship between the specific surface area,pore volume,pore size and heteroatom content of carbon materials and the capacitance value of capacitor was explored.The research details are as follows:1.One-pot synthesis of N-doped mesoporous carbon materials for high-performance supercapacitorsTEOS,TEA and TEAOH were polymerized by one-pot method to form a polymer precursor which was carbonized at different temperatures to form C-Si O₂ composites.Mesoporous carbon materials were prepared by removing Si O₂ by HF.The results show that the specific surface area of carbon material reaches 1050 m² g^-1 at 700^oC.In the three electrode system,the specific capacitance of TUD-700 is 360 F g^-1.In the two electrode system with Li NO₃ as electrolyte,the energy density of the capacitor reaches 30.4 Wh kg^-1.After 10000 cycles in KOH electrolyte,the capacitance retention is 96.5%of the initial value.2.Preparation of nitrogen sulfur co doped porous carbon with ultra-high specific surface area and Study on its supercapacitor performancePolypyrrole compounds were prepared by pyrrole sulfuric acid polymerization,and then nitrogen and sulfur co-doped carbon materials with ultra-high specific surface area were prepared by KOH activation.The specific surface area of the activated carbon is 3648m² g^-1 at 700 ^oC,and the specific capacitance is 454 F g^-1 at three electrode system.In the two electrode system with Li NO₃ as electrolyte,the energy density is as high as 37.9 Wh kg^-1.After 10000 cycles in KOH electrolyte,the capacitance value is 97.6%of the initial value.