Preparation And Electrochemical Performance Of Porous Carbon Materials With Controllable Morphology

Due to the rapid development of scientific technology,problems of fossil energy including pollution to environment,inadequate utilization of energy have been gradually exposed.Therefore,supercapacitors,clean and efficient storage devices,have emerged.Compared with traditional batteries,supercapacitors have many advantages,such as:near non-pollution,high safety performance,and fast charging and discharging speed.With them as energy storage devices,the energy efficiency can be greatly improved.In this way,supercapacitors are often put into use by the combination with renewable energy sources such as wind and solar energy.By the fact that the electrode material is one of the most important parts of the supercapacitor,the choice of material and type of electrode used in the preparation of high-performance supercapacitors is indeed crucial.At present,scholars have already discovered that the microscopic morphology,specific surface area and other specific factors of electrode materials will be the key factors to improve the performance.As the porous carbon has the characteristics of adjustable morphology and large specific surface area,it has become one of the focuses of current research.In this paper,a simple and effective method was used to prepare porous carbon materials with different morphologies,and the properties of the materials were improved by nitrogen doping,and the following studies were mainly carried out:1)The hollow boat carbon nanotubes with controllable morphology was successfully prepared by chemical activation:We mainly use Mn O₂ nanorods as hard templates,resorcinol-formaldehyde（RF）resin as carbon precursor,and ethylene diamine（EDA）catalyzes and introduces nitrogen,and KNO₃ as chemical activator to form hollow carbon nanotubes with different morphologies.The obtained N-doped hollow mesoporous nanotubes（N-HMNT-3）have a high specific surface area of 1 312.9 m²·g^-1.Under the condition of 1 A·g^-1,the measured specific capacitance is 277 F·g^-1.After 10 000 cycles of charging and discharging operations,the capacitor retention can reach 94.7%.2)By optimizing and improving the St（?）ber method,nitrogen-doped hollow bowl-shaped carbon spheres was prepared.Using Si O₂ as the hard template,covering the surface of the Si O₂sphere with m-aminophenol-formaldehyde resin,using ethylenediamine（EDA）as the nitrogen source,and removing the structure directing agent CTAB,nitrogen-doped hollow bowl-shaped carbon spheres were successfully prepared（N-HBCS）.In three-electrode system,the specific capacitance is 231 F·g^-1 under the condition of 1 A·g^-1.Moreover,even after testing under 10 A·g^-1,it was found that there was only attenuated by52 F·g^-1.After the cycle stability test,it was found that the stability of the N-HBCS we prepared performed well,and reached 97.4%.3)Nitrogen-doped hollow carbon nanotubes were prepared by using a simple one-pot method.By using Zn O nanorods as hard templates,resorcinol-formaldehyde（RF）resin as carbon precursor,and ethylenediamine（EDA）catalyzes and introduces nitrogen,nitrogen-doped hollow carbon nanotubes（N-HMCN-x）was successfully made.The thickness of the hollow carbon nanotubes is adjusted by changing the amount of RF added.N-HMCN-3 has a high specific capacitance value and excellent stability.Through BET analysis,it is found that N-HMCN-3 has a high specific surface area of 654.5 m²·g^-1.And,under the condition of 1 A·g^-1,the specific capacitance value is 291 F·g^-1.