Preparation And Supercapactitive Performance Of Petroleum Pitch Based Porous Carbon Materials

With the rapid development of society and the progress of techology,increasing energy consumption with each passing day.The continuous exploitation of coal,oil and natural gas leads to the increasing shortage of fossil energy and environmental pollution.Therefore,people's voice for energy conservation and environmental protection is getting higher and higher.By comparison,people prefer green renewable energy such as wind energy and solar energy.So it is urgent to find more suitable energy storage devices.As a new generation of energy storage components,supercapacitors have attracted wide attention due to their long life,high safety,wide temperature and environmental protection.Carbon materials play an important role in the process of energy storage and conversion.It is of great practical significance to develop new carbon materials and find cheap carbon sources.Porous carbon materials are widely used as electrode materials for supercapacitors because of their high specific surface area,simple preparation process,high chemical stability,good compatibility and environmental friendliness.Petroleum asphalt,a by-product of petroleum cracking,has high carbon content and low price,which is the most potential raw material for preparing porous carbon materials.In this paper,porous carbon materials were prepared from petroleum asphalt by liquid phase oxidation,template method and chemical activation method,and applied to supercapacitors to explore the causes of specific capacitance differences.?1?Aqua-mesophase pitch was prepared by liquid phase oxidation of petroleum asphalt,using aqua-mesophase pitch as carbon source,zinc nitrate as template,pore-forming agent and nitrogen source to prepare nitrogen and oxygen co-doped hierarchical porous carbon materials.The effects of template dosage and carbonization temperature on the electrochemistry of materials were systematically investigated.The sample HPC_1:4 has a high content of nitrogen?7.13%?and oxygen?6.48%?and a specific capacitance of 235.5 F g^-1 and 138 F g^-1 at current densities of1 A g^-1 and 50 A g^-1.In addition,HPC_1:4:4 shows excellent cyclic stability.Even after10,000 cycles at 10 A g^-1 current density,the capacity of HPC_1:4 does not decrease significantly,showing excellent electrochemical performance.?2?Mesoporous carbon materials were prepared by one-step carbonization using aqua-mesophase pitch as precursor and copper nitrate as template.The specific surface area and total pore volume of sample MC_1:4 can reach 443.9 m² g^-1 and 1.176cm³ g^-1.The nitrogen and oxygen contents of sample MC_1:4 are the highest,which are6.18%and 12.90%respectively.The specific capacitance of MC_1:4:4 reaches 257.5 F g^-1at 1 A g^-1 current density.Even at 100 A g^-1 current density,the specific capacitance of MC_1:4:4 can still reach 125 F g^-1.?3?Three-dimensional interchangeable porous carbon materials were prepared by chemical oxidation and in-situ activation with aqua-mesophase pitch as construction unit and KOH as activator.The specific surface area of UMPC₁ was 1520 m² g^-1.The total pore volume,micropore volume and mesopore volume were 0.731 cm³ g^-1,0.604cm³ g^-1 and 0.127 cm³ g^-1,respectively.At current densities of 0.5 A g^-1 and 1 A g^-1,the specific capacitance of UMPC₁ is as high as 421 F g^-1 and 383 F g^-1.Even at current densities of 100 A g^-1,the specific capacitance of UMPC₁ can still reach 230 F g^-1.Compared with the traditional activation method,the consumption of KOH is greatly reduced,and UMPC₁ has high specific capacitance and excellent rate performance,which is expected to become the most potential electrode material for supercapacitors.