Study On The Preparation And Capacitance Properties Of Nitrogen-doped Porous Carbon Materials Derived From Polyindole

With the progress of society and economic development,people's demand for energy is unceasingly increasing.The global energy obtaining depends heavily on fossil energy such as coal,oil and natural gas.However,fossil energy is non-renewable energy,and large-scale use of fossil energy will induce serious environmental problems,which is not in accordance with the concept of sustainable development.For the sake of facing with the increasing demand for energy and solving these urgent environmental problems,it is necessary to develop green energy and new energy storage equipment.Among numerous energy storage systems being developed?such as fuel batteries,lithium batteries,and super-capacitors,etc.?,the super-capacitors have attracted wide attention thanks to their long life,high power density,high safety and environmental pollution-free.Currently,the major problem that limits the application is the low energy density of supercapacitors.How to improve the energy density of supercapacitors on the premise of maintaining high power and long life is an urgent problem to be solved.Carbon materials are the most studied super-capacitor materials featuring as low price,high life stability and so on,and supercapacitors based carbon materials have been commercially applied.In recent years,conductive polymers,as the precursor preparation of carbide heteroatom doped with carbon materials have been studied and the electrode with high performance have been obtained.However,the preparation of porous carbon materials using as precursor has rarely been reported.This paper uses chemical oxidation to polymerize indoles and take polyindole as precursor and prepares nitrogen doped porous carbon materials by carbonizing precursor with KOH as activator under high temperature.Specific research is as follows:?1?Using polyindole as precursor and KOH as activator,the optimum conditions were found by changing carbonization temperature and the concentration of KOH.The prepared material possesses the highest specific surface area of 2238 m² g^-1.Carbon cloth is used as the current collector in the preparation of the electrode.When the current density is 1 A g^-1,the specific capacitance of the prepared electrode is 328 F g^-1,presenting an energy density of around 15 Wh kg^-1,and the capacitance retention rate is 91%after 1000 cycles.?2?The use of binders during the preparation of electrodes can lead to the degradation of the performance of the electrodes.Polyindole and KOH were mixed and coated on carbon fibre cloth,and then carbonized it in tubular furnace at high temperature.Nitrogen doped with three-dimensional porous carbon material was successfully prepared,and no binder was used during the preparation of the electrode.The specific capacitance is 416 F g^-1 at 1 A g^-1.After 10,000 cycles,the device can still maintain 91.8%of the initial capacitance.?3?Graphene is a two-dimensional material with excellent conductivity.In the third experiment,graphene oxide and polyindole are compounded to prepare PIn/GO composites.The composites are coated on carbon cloth and carbonized at high temperature.The specific capacitance of the prepared electrode is 451 F g^-1 when the is 1 A g^-1,and the ratio is increased to 72%.These results suggest that the prepared porous carbon materials have potential application prospects in energy storage devices with high performance.