Preparation Of Nitrogen-doped Porous Carbon Material And Its Electrochemical Performance

With the rapid development of industry and the increasing demand for electrical energy in people’s lives,ordinary capacitors can no longer meet the increasing demand,which forces scientists to develop better electrical energy storage and supply systems.Supercapacitors have been widely used in recent years due to their excellent charge storage capacity and short charge and discharge characteristics.However,porous carbon materials have broad application prospects in the electrochemical field due to their excellent electrical conductivity and low temperature limitation.However,after a certain high temperature treatment of carbon materials,the surface generally appears to be insensitive to chemical substances.After doping with nitrogen atoms,the effect of increasing active sites and specific surface area is achieved.Therefore,this article uses different nitrogen doping methods to prepare porous carbon materials with different morphologies,and specifically studies their electrochemical properties.The main content of the paper is as follows:1)Using the cigarette filter as a template and ammonium phosphate as the nitrogen/phosphorus source,through a simple impregnation activation process,a nitrogen-doped porous carbon sheet（MCF-x）is prepared.The electrode material with the best electrochemical performance is explored by changing the doping ratio of the activator.When the mass ratio of ammonium phosphate to cigarette filter is 3,the nitrogen-doped porous carbon sheet has a high specific surface area(1 486 m²·g^-1),a mesoporous pore size（2.1 nm）and a higher nitrogen content（4.15%）.When it is used as an electrode material,it exhibits excellent specific capacitance characteristics.When the current density is 1 A·g^-1,it has a high specific capacitance performance of 342 F·g^-1.The nitrogen-doped porous carbon sheet greatly reduces the transport resistance of electrolyte ions,thereby greatly increasing the specific capacitance.Generally,it is expected that this easy-to-synthesize heteroatom-doped porous material will become an effective electrode material for supercapacitors.2)Using ordered mesoporous resin spheres as a template and dopamine as a nitrogen source,through a one-pot synthesis strategy,nitrogen-doped ordered mesoporous carbon spheres（N-MCS）were prepared.Ordered mesoporous resin spheres（MCS）were synthesized by using Pluronic F127 as a template to mediate phenol formaldehyde.The prepared ordered mesoporous resin spheres are dispersed in a system of water and ethanol at room temperature,and fully mixed with the sole nitrogen source dopamine.The dopamine forms a uniform shell outside the MCS to achieve the purpose of nitrogen doping.The prepared N-MCS has high specific surface area(719 m²·g^-1),high nitrogen content（5.57%）and uniform pore size（3 nm）.In the alkaline electrolyte,due to the unique structural characteristics and ideal doping of N atoms,N-MCS shows a high specific capacitance of 325 F·g^-1 under the condition of 1 A·g^-1,which proves that it is in Huge potential applications in supercapacitors.3)Using SBA-15 as a template to limit the synthesis of resin balls,by dispersing different amounts of SBA-15 in a triaminophenol formaldehyde solution to prepare nitrogen-containing spherical carbon materials（HCP-x）with different morphologies（where x represents The degree of damage）,including the entire sphere（0）,partially damaged sphere（1）,uniform hemisphere（2）and broken hemisphere（3）.When the addition amount of SBA-15 is 0.2 g,a hemispherical structure with uniform particle size is synthesized and has a stable skeleton structure.When used as an electrode material,the sample has excellent electrochemical stability（95%）.After analysis and testing,the sample has a surface area of 465 m²·g^-1,a concentrated pore size of 3 nm and a nitrogen content of 3.75%.