| In this thesis,graphite oxide was prepared by improved Hummers method,and poly(aniline-co-pyrrole)(PACP)was prepared by chemical oxidation polymerization method by changing the the molar ratio of oxidizing agent and monomer.The reduced graphene oxide/poly(aniline-co-pyrrole)composite(3DAP)was prepared by mixing GO and PACP as precursors,combin g with solution blending method and hydrothermal reduction method.The PANI nanofibers have been used as efficient seeds in the chemical polymerization of pyrrole monomers to obtain core-shell poly(aniline-co-pyrrole)(PANP),which was mixed with the suspension of graphene oxide(GOS)to prepare core-shell poly(aniline-co-pyrrole)/reduced graphene oxide composite(3GAP)using a hydrothermal method.P-phenylenediamine(PPD)as nitrogen source and reducing agent was mixed with graphite oxide suspension and then mixed with PACP to prepare nitrogen-doped graphene/poly(aniline-co-pyrrole)composite(3DPP).Scanning electronic microscopy(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),Fourier transform infrared spectra(FT-IR),Raman spectra(Raman),and electrochemical measurements were performed to investigate the morphology,structure,s pectral characteristics,and supercapacitive performance of 3DGS,PACP,PANP,3DAP,3GAP and 3DPP composites,and the formation mechanism of 3DAP,3GAP and 3DPP was further uncovered.The results show that the morphology of PACP was gradually regular granular at the nanometer scale with the increase of the molar ratio of oxidizing agent and monomer,and the particle size increased first and then decreased.The thermal stabilities have been significantly improved compared with the homopolymer.The best electrochemical performance was obtained when the molar ratio of oxidizing agent and monomer was 2:1,and the specific capacities reached 447.5 F·g-1 at the current density of 0.5 A·g-1.During the one-step hydrothermal method processes to prepare 3DAP,PACP was inlaid into the three-dimensional network structure,which not only improve the utilization of active substances,but also achieve the uniform dispersion of the copolymer.Furthermore,the synergies of 3DGS and PACP make 3DAP show a excellent supercapacitor performance,the specific capacity was 628.5 F·g-1 at a current density of 0.5 A·g-1,and its specific capacity was as high as 384 F·g-1 even at a high current density of 10 A·g-1.The retention rate was 86.1% after 1000 charge-discharge cycles at a current density of 1 A·g-1.During the combing PANP and GO to prepare 3GAP,PANP was inlaid into the three-dimensiona structure,in which significant sheet folds appeared and the excellent network of 3DGS was maintained.The 3GAP-X composites show the high current charge and discharge ability and cycle performance,which was attributed to the synergies of GS substrate and PANP nanofibers.With the increase of the mass ratio of GO to PANP,the specific capacit ies of 3GAP-X increase and then decrease.Among them,the 3GAP-0.9 electrode has the largest specific capacity,which reached 687.5 F·g-1 at a current density of 1 A·g-1 and reached 417 F·g-1 at a current density of 10 A·g-1.The retention of the specific capacity was 88% after 1000 charge-discharge cycles,and the optimum electrochemical performance was exhibited compared with homopolymer.The 3DPP composites were prepared by using p-phenylenediamine as nitrogen source and reducing agent,GS layer gradually transformed to helical porosity,and the PACP particles were uniformly dispersed in the spiral porosity and the edge of the lamellae to form 3D jellyfish topography with the change of nitrogen doping amount.The synergistic effect between GS layer and PACP prepared in 3DPP-N was effective,when the quality of PPD is 75 mg,the 3DPP-3 composite has the best supercapacitive performance.The specific capacity was 693.5 F·g-1 at a current density of 0.5 A·g-1,and the retention rate of the 3DPP-3 electrode was 90% after 1000 charge-discharge cycles,which suggest excellent electrochemistry reversibility,magnification performance and cyclic stability. |
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