Studies On Preparation And Performances Of Nitrogen And Oxygen Co-doped Carbon Materials For The Application Of Supercapacitor

Electric double layer capacitors(EDLC)have received considerable attention as a new type of energy storage device,owing to their higher energy density than conventional capacitors and higher power density than batteries.The property of the electrode material is a important factor that determining the performance of the supercapacitor.Carbon materials are more earlier and more widely used materials than conducting polymers and metal oxides.Although a lot of researchers have done a lot of research on the common carbon materials used in supercapacitors in recent years,it is still difficult to make a breakthrough.Therefore,it is very important to design and prepare new carbon materials for supercapacitors.In addition,the single carbon material can not have excellent performance in all aspects of supercapacitors due to its own shortcomings.It is an effective way to improve the performance of supercapacitor by making composite materials with different carbon materials.In this study,first,we designed and prepared the carbon nanobelts with a new micromorphology using hydroquinone and formaldehyde as the main material,this material has a conducting network connected to each other,thus having excellent conductivity.In order to improve the electrochemical performance of carbon nanobelts,we have prepared the nitrogen and oxygen co-doped carbon nanobelts(NCNBs)by controlling carbonization and activation process.The as-prepared activated NCNBs-45 possess a high capacitance of 255 F/g at the current density of0.25 A/g and show an excellent capacity retention of 50.2%when the current density increase from 0.25 to 150 A/g.Moreover,HCNs-45 electrode exhibits superior electrochemical stability with 96.2%capacity retention after 10000 cycles at 5.0 A/g.Then,we use a one-step route to fabricate poly(aniline-co pyrrole)(PACP)copolymer hollow nanospheres by the polymerization of pyrrole and aniline in Triton X-100 solution.The nitrogen-enriched precursor becomes HCNs after carbonization of high temperature and activation by ammonia.The preparation of hollow carbon nanospheres by this method has the advantages of safe,simple and high productivity,the as-prepared HCNs has nanoscale and possess ultra-high SSA(up to 2693 m~2/g).The as-prepared activated HCNs-45 possess a high capacitance of 387 F/g at the current density of 0.25 A/g,and maintains 152 F/g of the highest capacitance even at a current density of 20 A/g.Moreover,HCNs-45 electrode exhibits superior electrochemical stability with 92.5%capacity retention after 10000 cycles at 5.0 A/g.Finally,because of composites can combine the performance advantages of the component materials and give new properties to the composite,NCNBs have excellent conductivity and excellent rate performance and HCNs have the advantages of high nitrogen content and higher specific capacitance,We have prepared the compound material of nitrogen and oxygen co-doped carbon nanobelts-hollow carbon nanospheres(NCHCs).This composite material combination the advantages of NCNBs and HCNs,As a supercapacitor electrode material,NCHCs-50%possess a high capacitance of 348 F/g at the current density of 0.25 A/g,and maintains 152 F/g of the highest capacitance even at a current density of 156 A/g.Moreover,NCHCs-50%electrode exhibits superior electrochemical stability with 93.8%capacity retention after 10000 cycles at 5.0 A/g.