Preparation And Research Of Mesoporous Carbon Ror Supercapacitor Electrode Materials

Supercapacitor is a new type of energy storage devices between traditional capacitorand the battery we always used. Supercapacitor has the features of high power density,rapid charge and discharge, high energy density, long cycle life, low of price,maintenance-free, friendly to the environment, safety, etc. Thus supercapacitor draws wideattention from scientists all over the world, and has great market potential. It can bewidely used in areas of mobile communication, transportation, aerospace and defensescience and technology.In this paper, mesoporous carbon (MCs) and nitrogen-doped mesoporous carbon(NMCs) were prepared by high-temperature carbonization of precursors (glucose, glucoseand melamine) under nitrogen. In order to tune the pore size of MCs for supercapacitor,we can change the atmosphere pressure by controlling the amount of nitrogen in thecarbonization process of carbon precursors without template. Thus a perfect combinationof electric double-layer capacitance and pseudocapacitance was achieved. BET, HRTEM,XPS and CV, EIS, Galvanstatic charge-discharge were used to analyse and characterizethe morphology and structure and the electrochemical performance of the MCs and NMCselectrode materials.The results revealed that the porous carbon materials we obtained were amorphouscarbon. The porous carbon materials we obtained at620°C for4h in vacuum anddifferent nitrogen pressure. The MCs samples were microporous carbon materials in thecondition of vacuum and nitrogen pressure of0.05MPa. It was obvious in the nitrogenpressure of0.05MPa and0.1MPa that the pore size distribution changed from microporesto mesoporous and the distribution of pore size of MCs was2-4nm and2-3.5nm,respectively. With the increase of nitrogen pressure, the distribution of pore size was lessbecause the high pressure would compress the pores and impede the decomposition ofglucose.The NMCs prepared by different mass ratios of melamine and glucose showed thatthe N1s type was pyidinic (N-6) type nitrogen, pyrrolic/pyridonic (N-5) nitrogen andquaternary/graphitic (N-Q) nitrogen. The percentage of atoms was0.46%,1.04%å'Œ0.78%, respectively.The results of electrochemical test showed that the MCs samples activated by KOH had a better electrochemical and reversibility. The MCs sample prepared in the nitrogenpressure of0.05MPa had a highest specific capacitance of250F·g-1. After1000cycles atthe current density of2.0A·g-1, it lossed no more than4.5%of initial capacitance,showing good cycling stabilityThe NMCs samples were prepared by high-temperaturecarbonization of melamine and glucose with the different mass ratios of1,2and6in thenitrogen pressure of0.05MPa. The NMCs had a highest specific capacitance of442.5F·g-1when the mass ratio of melamine and glucose was2. Furthermore, the specificcapacitance of the MCs and NMCs samples at the current density of2.0A·g-1calculatedfrom charge-discharge curves were250F·g-1and442.5F·g-1, respectively.