Preparation And Capacitive Performance Of Nitrogen-containing Polymer-derived Porous Carbon

The rapid development of portable electronic has been stimulated extensive research in new energy storage technologies.Among them,supercapacitor?SC?have attracted highly attention due to their higher power density,fast charging/discharging rate,long lifetime properties and environmental benignity.In this paper,nitrogen-containing polymers?polypyrrole,polyaniline and LA133?were employed as carbon sources for the synthesis of a series of polymer-derived porous carbons,using potassium hydroxide as the activator.The morphology,porous structure and electrochemical performance were studied in detail by TEM,SEM,FTIR,XPS,XRD,Raman,BET,and the electrochemical means.The main conclusions are as follows.Firstly,N/P co-doped porous carbon was prepared from polypyrrole as carbon sources through one-step carbonization/activation at 750 ^oC in nitrogen atmosphere.Results show that the specific surface area of carbon material?A-Z0?after activation was found to be 1433 m² g^-1 with a total pore volume of 0.96 cm³ g^-1.Nitrogen and phosphorus contents were 1.78 at%and 0.24 at%,respectively.Specific capacitances of A-Z0 reached 209.3 F g^-1 and 176 F g^-1 at current densities of 0.5 A g^-1 and 30 A g^-1,respectively,showing relatively high specific capacitance and excellent rate performance.In addition,A-Z0 exhibited superior cyclic stability(the loss of the capacitance was only 2%after 10000 cycles at 4 A g^-1).In neutral electrolyte,the symmetrical two-electrode supercapacitor was assembled using the A-Z0 materials as positive and negative electrodes,which delivered energy density as high as 13.3Wh kg^-1.Second,a ternary system?PEG/PANI/MgO?was evolved into hierarchically porous nanoflake-connected carbons by the template-assisted carbonization and further activation.The influences of mass ratio in ternary system and pyrolysis temperature on the morphology,specific surface area and pore structure,were explored.The study indicated that,when KOH-activated product?APC3-700?using the PEG/PANI/MgO system in 10:3:7 mass ratio under 700 ^oC showed remarkable features of high BET area(1455 m² g^-1),plentiful pores and O/N co-existed structure.As electrode material for supercapacitor,the enhanced capacitance of 225 F g^-1 at 1A g^-1 was obtained for APC3-700,and can remain 91%capacitance was remained at high current of 20 A g^-1.Besides,APC3-700 electrodes delivered a power density of4274 W kg^-1 at 20 A g^-1 and an energy density of 6.3 Wh kg^-1 at 1 A g^-11 with significantly outstanding cyclability?near 100%retention after 20000 cycles?.Thirdly,a kind of novel hierarchical porous carbon?A-LAC2?was prepared by using waterborne adhesive?15%LA133,acrylonitile copolymer?as the carbon source via a simple one-step carbonization/activation process.A new strategy of HCl-assistant flocculation was proposed in this work.As a result,the BET surface area and total pore volume of A-LAC2 was up to 2446 m² g^-1 and 1.29 cm³ g^-1,respectively.Besides,the A-LAC2 possessed high specific capacitance(317.5 g^-1 at0.5 A g^-1,258.9 g^-1 at 30 A g^-1)and high-rate capability?81.5%retention?with the increase of the current density from 0.5 A g^-1 to 30 A g^-1.It also displayed a high electrochemical performance in the aqueous symmetric supercapacitor(1 mol L^-1Na₂SO₄ aqueous electrolyte,energy and power densities of 17.8 Wh kg^-1 and 7064W kg^-1)or solid-state symmetric supercapacitor device(6.6 Wh kg^-1/3486 W kg^-1).All the results indicated that the proposed method in this research may provide a simple process to guide the rational design of carbonaceous materials for high efficient storage.