Preparation And Electrochemical Study Of N-Doped Carbon Materials Based On Biomass

With close attention paid to the world ecology and economy,Supercapacitors have received considerable attention,owing to their high power density,extremely long cycle life and fast charging/discharging rates.It has been reported that certain nitrogen doping seems to be the most promising method for enhancing capacity and electronic conductivity.N-doped carbons are synthesized from variety of materials,and biomass materials have become the hot choice due to low cost,renewable and environment friendly.In this paper,protic polyanion(ionic liquids)was synthesized by the direct reaction between a polyacid with small molecular organic bases or polymerization of polymeric small molecular protic ionic liquids,N-doped porous carbon material prepared by protic polyanion(ionic liquids)through KOH hydrothermal and activation method and respectively.The morphology and microstructure of the materials were investigated in depth by SEM,TEM,XRD,BET,XPS,Roman and TGA.In addition,the electrochemical performances of the as-obtained nanoporous carbons were measured in a two-electrode system,respectively.Nitrogen-doped Porous Carbon Materials from Alginic-based protic polyanion(ionic liquids)were obtained.The alginic acid was used as a green polyacid reacting with several organic bases to from serials of alginic-based protic polyanion(ionic liquids)(APILs)according the synthesis principle of traditional small molecule protic ionic liquids,which were used as precursors for the synthesis of nitrogen-doped porous carbon materials via carbonization and KOH activation method.The structural tunability and features of the carbon materials have been investigated systematically,and the electrochemistry properties also have been studied by assembling the carbon materials into symmetric supercapacitor.The correlation between the precursor structures and the properties of the final carbon materials are also discussed towards insights in the synthesis of specific carbon materials with controlled structure and properties.Nitrogen-doped Porous Carbon Materials from chitosan-based protic polyanion(ionic liquids)were obtained.As a renewable natural biomass,chitosan offers very attractive raw materials for the synthesis of carbon materials.Here we propose a new and cost-effective way to produce chitosan-based hierarchical porous carbons by the union of hydrothermal carbonization and chemical activation(such as KOH,KCl and K2 Fe O4).The effect of the preparation methods(such as carbonization and activation)on the Nitrogen content,the Nitrogen form and pore structures were be studied,and the new theory and new methods of controllable preparation of new-type hierarchical structured N-doped carbon materials will be established finally.With the supercapacitor as the application model,the structure-activity relationship between the material structures and electrochemical performance will be studied and elucidated.Pretreatment at 400°C gives high performance carbon materials(surface area up to 3300 m2 g-1 and 2.83 at% nitrogen),a significantly high gravimetric capacitance of up to 367 F g-1 at current density of 0.1A g-1,as well as a high cycling stability of 94 % capacitance retention after 20000 cycles.