Functional Modification Of Ordered Mesoporous Carbon And Its Electrochemical Performance

In this paper,ordered mesoporous carbon materials were prepared by soft template method,and the ordered mesoporous carbon materials were functionalized by various elements to enhance the electrochemical performance.The structure and morphology of materials were characterized by means of TEM,XRD,SAXS,XPS and nitrogen adsorption desorption.Electrochemical performance was tested by electrochemical workstation,and the influence mechanism of functional modification of different elements on ordered mesoporous carbon was analyzed and summarized.?1?The ordered mesoporous carbon materials with high specific surface area and specific capacitance were successfully prepared via the solvent evaporation self-assembling?EISA?method by using the block copolymer F127 as template,phenol formaldehyde resin as carbon source,pyrrole monomer and urea as nitrogen sources simultaneously.The structural characterization shows that the mesoporous carbon materials have ordered two-dimensional hexagonal structure,high specific surface area?1351 m²/g¹469 m²/g?and pore volume(1.62 cm^3/g¹.92 cm³/g),and the pore size distribution is concentrated around 4 nm.Nitrogen elements exist in the framework of mesoporous carbon atoms mainly in three forms:pyridine nitrogen,pyrrole nitrogen and graphite nitrogen.Electrochemical tests showed that the N-doped ordered mesoporous carbon has excellent electrochemical performance.By controlling the amount of nitrogen source,the maximum specific capacity can reach 304 F/g at the current density of 1 A/g.More importantly,the N-doped mesoporous carbon materials still retain the specific capacitance of 94%after 1000 charge/discharge cycle numbers,which shows the excellent capacitance characteristics and cycle stability as the supercapacitor electrode material.?2?The Fe/N-codoped ordered mesoporous carbon material with large pore size,high surface area the Specific capacitance were prepared by using the block copolymer F127 as soft template,phenol-formaldehyde resol as carbon source,pyrrole monomer as the nitrogen source,FeCl₃ as the iron source through the radical polymerization and solvent evaporation induced self-assembly?EISA?.The structural characterization showed that the mesoporous carbon materials maintained the ordered porous structures.In addition,the pore channel showed the curved shape and relatively uniform pore size distribution.The pore size of the prepared mesoporous carbon material could reach 18nm,and the specific surface area was 288.65 m²/g⁴96.58 m²/g.Nitrogen atoms exist mainly in the form of carbon atoms in the form of pyridine nitrogen and graphitized nitrogen.The iron atoms exist mainly in the forms of?-Fe and Fe₃C.Electrochemical tests showed that the F/N-doped ordered mesoporous carbon materials with different capacitance were obtained through adjusting the molar ratio between iron sources and nitrogen.The highest specific capacitance can reach 257 F/g at sources.the current density is 1 A/g.Meanwhile,the mesoporous carbon materials still retain the specific capacitance of 92%after 1000 charge/discharge cycle numbers,which shows the excellent capacitance characteristics and cycle stability.?3?The N/P-codoped ordered mesoporous carbon materials with high surface area and specific capacitance were synthesized via the solvent evaporation induced aggregating assembly?EIAA?approach by using the phenolic resin as carbon source,ethanol and deionized water as solvent,the block copolymer F127 as surfactant,the pyrrole monomer and amino sanya methyl phosphoric acid?ATMP?as nitrogen source and phosphorus source,respectively.The structural characterization shows that the N/P-codoped ordered mesoporous carbon materials have the surface morphology of layered stacking,ordered two-dimensional hexagonal structure,uniform pore size distribution,high specific surface area?up to 1233.27 m²/g?and pore volume?1.73 cm³/g?,and pore size distribution is concentrated at 4⁵ nm.Additional,the nitrogen and phosphorus were covalently bonded with carbon atoms in the carbon skeleton.The nitrogen atoms mainly existed in the form of pyrrole nitrogen,pyridine nitrogen and graphitized nitrogen.Phosphorus atoms mainly existed in the form by P-C bond and P-O bond.The electrochemical tests show that the N/P-OMCs has the extremely high specific capacitance for 382.3 F/g at the current density of 1 A/g and in KOH electrolyte solution of 2 M.Moreover,the specific capacitance still retain the initial value of 95%after 1000cycles,which proves its excellent electrochemical performance and wide application prospect as electrode materials in supercapacitors field.