The Study On The Carbon Electrode Materials Based On Graphene And The Graphitization Of Fibers

Supercapacitor is a new kind of energy device,which has attracted widespread attention aroud the world due to its high rate capability and fast charge and discharge characteristic.The electrode materials have been regarded as the key factor to affect supercapacitors performance.Among these electrode materials,Nitrogen-doped carborn materials can be used as the electrode materials with high electrochemical properties because of their high pseudocapacitance and cycle stability.This paper focused on the study of high performance electrode materials for supercapacitors and the low temperature graphitization of poly?o-phenylenediamine?fibers.The main research content and results of the text are summarized as follows:In this paper,we prepared graphene hydrogels using o-phenylenediamine?OPD?and grapheneoxide?GO?in the hydrothermal process,and then got a porous carbon/graphene material named PGC10/500 with three-dimensional?3D?cross-linked network and high Nitrogen-doped content.Meanwhile the PGC10/500 showed a high specific capacitance of 673F/g at current density of 1A/g,as well as a high capacitance retention of 94.8%at current density of 5 A/g after 1000charge-discharged cycles.At the same time,the density of PGC10/500 is 1.06cm³/g with a volumetric capacitance of 713F/cm³ at current density of 1A/g.We prepared graphene hydrogels using OPD,GO and single-walled carborn nanotubes?SCNT?in the hydrothermal process,and used SCNT to block the stack of graphene layer when directly dried the hydrogels.And then we got a graphene/carbon material named PGSC5/500 with a stratified structure and a high content of nitrogen atoms.Meanwhile the PGSC5/500 showed a high specific capacitance of 569.2F/g at current density of 1A/g,as well as a high capacitance retention of 95.2%at current density of 10 A/g after 1000 charge-discharged cycles.At the same time,the density of PGC10/500 is 1.36cm³/g with a volumetric capacitance of 774.1F/cm³ at current density of 1A/g.The polymerizing poly?o-phenylenediamine?fiber?POPD-F₂?was got through a two-step method and the carborn fiber?POPD-CF?can be prepared at 950?.It is turned out that the POPD-F₂ had little different to the POPD-F₁ prepared through the one-step method on the morphology and can maintain the fiber morphology in the carbonation process.What's more the carborn fiber POPD-CF with high degree of graphitization was obtained through annealing the POPD-F₂ at a low temperature?950??.