Fabrication Of 3D Ordered Honeycomb-like Nitrogen-doped Carbon/PANI Composite And Its Ectrochemical Performance

As an efficient energy storage and clean energy source,supercapacitors have attracted more and more attention.It can provide a higher power density,longer cycle life,faster charging and discharging time.And it is a clean,environmentally friendly,safety,large capacity,strong energy storage device.The electrode material is the key factor affecting its performance,so research and development of materials with high energy and stable performance have become the research hotspot.Carbon materials with various nanostructures,high specific surface area,relatively low cost,good conductivity,long cycle life and good stability have been widely used,but their theoretical specific capacitance value is lower.Polyaniline has become a promising electrode material for pseudocapacitors due to its low production cost,simple synthesis methods,multiple redox states and high theoretical specific capacitance.However,it is prone to expansion and contraction of volume during high-speed charging/discharging,resulting in poor cycle stability and serious capacitance decay.Therefore,more and more researchers are devoting to fabrication the carbon materials and polyaniline composites to solve the limitations of single materials on supercapacitors and expand their commercial development.Among them,three-dimensional porous nitrogen-doped carbon and PANI composites have attracted much attention.Based on the above analysis,three-dimensional ordered honeycomb nitrogen-doped carbon matrix?HNC?was used as carrier to prepare the HNC/PANI composites.The main research contents are as follows:SiO₂ nanospheres were synthesized by modified St?ber method as templates.Carbon and nitrogen precursors were synthesized by in situ polymerization of PANI.Carbonization and etching were carried out at high temperature to obtain three-dimensional ordered honeycomb nitrogen-doped carbon matrix with high specific surface area.And the HNC/PANI composites were obtained by the PANI was coated on the surface of HNC through in situ assembly.At the same time,the effects of the precursors prepared by polyaniline with different contents on the properties of the composites were also studied,the effect of carbon matrix and aniline concentration ratio on properties of composites as well as the morphology of carbon matrix on the properties of composites were also discussed.The morphology and structure of HNC carbon matrix and HNC/PANI composites were characterized by SEM,TEM,FT-IR,XRD,BET and Raman spectroscopy.The capacitance and cyclic stability of HNC carbon matrix and HNC/PANI composites were studied by CV,GCD and EIS.Through the analysis and research,the following conclusions are drawn:?1?The results show that the prepared HNC has a honeycomb-like structure with interconnection and uniform pore size,uniform distribution of nitrogen elements,specific surface area of 1056 m² g^-1 and total pore volume of 1.04 cm³ g^-1.The electrochemical analysis shows that the ordered carbon material HNC has excellent electrochemical properties,and the specific capacitance of HNC reaches 215 F g^-1 at current density of 1 A g^-1,and when current density up to 10 A g^-1,the specific capacitance of HNC reaches to 215 F g^-1 and the specific capacitance still reaches 92.2%of the initial capacitance after 5 000 constant current charging/discharging cycles.?2?Through the microscopic characterization of HNC/PANI composites,PANI nanofibers were evenly loaded on the surface of honeycomb-like carbon matrix,and the porous structure did not change significantly during the polymerization process.The electrochemical analysis shows that the specific capacitance and cyclic stability of HNC/PANI composites are significantly improved.The specific capacitance of HNC/PANI composites reaches to 686 F g^-1 at 1 A g^-1 of current density and 74.1%initial capacitance is retained at 10 A g^-1 of current density.After 5 000 cycles of charging/discharging,the capacitance of HNC/PANI composites can be kept at 87.8%,which is better than that of disordered template nitrogen-doped carbon/polyaniline?NDC/PANI?composites of 76.3%.Therefore,the preparation of composite materials with excellent properties is expected to become the electrode materials of high performance supercapacitors.