| The three-dimensional ordered porous carbon material has many advantages,such as wide source of raw materials,large specific surface area,and stable physical and chemical properties,so it has great application prospects in supercapacitor electrode materials.As a main by-product of petroleum processing,pitch is cheap and has a high carbon yield.Using it as a high-quality precursor for high-performance supercapacitor electrode materials greatly increases the additional utilization value of pitch.However,pure carbon materials only use the double electrode layer principle for energy storage,resulting in a low specific capacitance,which limits the improvement of energy density.Introducing nitrogen atom into the carbon material can effectively improve the wettability between the electrode material and the electrolyte,provide a more effective transmission channel for ions,and thus improve the electrochemical performance of the carbon material.In this work,MCM-48 is used as a template,mesophase pitch is used as a carbon source,and a series of ordered porous carbons are prepared by liquid phase impregnation-preoxidation-carbonization-HF etching.Through the electrochemical workstation,the effect of the mass ratio between mesophase pitch and MCM-48template on the electrochemical performance of ordered porous carbon was explored,and the best mass ratio of MP and MCM-48 for preparing mesophase pitch-based ordered porous carbon material were determined.The effects of different carbonization temperatures on the morphology,pore structure and electrochemical properties of ordered porous carbon materials were explored by SEM,TEM,XRD,XPS and BET.The results suggest that OMC-0.2-800（the optimal mass ratio of MP and MCM-48 is 0.2 and the optimal carbonization temperature is 800℃）with broccoli morphology has the best electrochemical performance(specific capacitance at 1 A g-1is 265.4 F g-1;energy density is 16.9 Wh kg-1at power density of 1000 W kg-1),the largest specific surface area(1369.9 m2g-1),and the highest oxygen content（6.37wt%）.Nitrogen-rich polypyrrole and mesophase pitch are used as precursors,nitrogen-doped porous carbon（NPC）was prepared by controlling the nitrogen-doped content of ordered porous carbon materials by different mass ratios of pyrrole and mesophase pitch,and explored the effect of different pyrrole content on the electrochemical performance of NPC.After determining the optimal nitrogen-doped content,the effects of different carbonization temperatures on the morphology and chemical structure of NPC were further explored by SEM,TEM,XRD,FTIR,Raman and other methods.The results show that NPC-3-700（the best mass ratio of pyrrole and mesophase pitch is 3 and the best carbonization temperature is 700℃）with uniform layered structure has the best electrochemical performance(specific capacitance at 2 A g-1is 232.2 F g-1;energy density is 15.3 Wh kg-1at a power density of 1000 W kg-1),but has a medium specific surface area(495.9 m2g-1)and nitrogen content（4.48 wt%）,and with the temperature rises,the nitrogen element gradually decreases.This phenomenon is because the introduction of nitrogen atom will produce pseudocapacitance,which is beneficial to improving the capacitance performance of the material.In order to further explore the effect of nitrogen-doped on ordered porous carbon materials,the same experimental method and the same processing temperature（700℃）was used to directly carbonize the precursor without adding pyrrole and obtain the porous carbon of none nitrogen-doped（PC-700）.The results show that the specific capacitance of the sample NPC-3-700 is 53.6 F g-1higher than that of the non-nitrogen-doped sample PC-700 at a current density of 2 A g-1.It is further proved that the introduction of nitrogen will produce pseudocapacitance,which is conducive to improving the capacitance characteristics of the material. |
