The Preparation Of N-doped Carbon Nanotubes And Its Research Of Electrochemical Performance

Because of the growing shortage of oil resource,and the pollution to theenvironment which is from disel-engine exhaust of burning oil is becoming increasingserious, people are studying a new energy device instead of oil resource. As for thestudy of chemical power source, it has been a research hot spot and has made someachievements. Supercapacitors with their excellent electrical properties, can substitute thetraditional oil partially or completely to be used for Vehicles of traction and start-up.Besides, Supercapacitors have much wider applications than the traditional chemical cells.In the research of supercapacitors, it is of great practical value and theoretical significanceto develop electrode materials with high specific capacity.Introducing non-carbon atom, nitrogen to the phase of carbon materials with highspecific surface area, electrode materials in supercapacitors, can improve itselectrochemical performance as electrode materials. In this paper, the composition ofconducting polymer （polyaniline and polypyrrole are studied here） with KC-CNT whosediameters are40nm and KF carbon nanotubes （KF-CNT） whose diameters are70nmwhich and their carbonization after synthesis are studied, and the electrochemicalperformance has been studied as electrode materials of supercapacitors. The main studiesof this paper as follows:1. Pyrrole and aniline are coated on carbon nanotubes, respectively, by in-situpolymerization, and then PPY-CNTs and PANI-CNTs are obtained. And then, they arecarbonized at700℃to get N-doped carbon nanotubes.2. Transmission electronic microscopy （TEM）、Laser raman spectroscopy（LRS） andX-ray photoelectron spectroscopy （XPS） are used to observe the surface morphology andthe composition of the materials. The results show that the conducting polymer can coaton the surface of carbon nanotubes smoothly, and nitrogen is doped in it successfully andthe structure of carbon nanotubes is not damaged after carbonization.3. Cyclic voltammetric measurements （CV） and electrochemical impedance spectrum（EIS） are used to discuss the electrochemical performance of the prepared materials. Theexperiment results suggest that after CNTs are doped with nitrogen, their specific capacityis remarkably higher than the original CNTs. Among them, when the N-CNT electrode isin6mol·L^–1KOH, the specific capacity of N-CNT carbonized from PANI-KC-CNT andcarbonized from PPY-KF-CNT can provide more than5-fold and14-fold improvement,respectively, at the current density of100mA·g–1.4. Cycle performance results show that the cycle performance of the N-doped carbonnanotubes is similar to that of the original carbon nanotubes, so it has good cycleperformance required by the electrode of the super capacitor materials. Therefore, theresearch of this paper can provide theoretical and experimental foundation for finding and preparing nitrogen-doped carbon material with better performance.