Control Of Coal-based Carbon Anode Materials And The Electrochemical Performance Study Of The Supercapacitor

As a new type of energy storage device different from batteries and capacitors,supercapacitors are often used in the field of energy storage systems due to their high power density,energy density and stable cycling capability,such as the automotive industry,aerospace and aviation,communications,etc.In order to further improve the utilization rate and added value of coal,it is of great significance to design and prepare high-performance,low-cost coal-based electrode materials.In this paper,coal-based carbon materials are prepared by pretreatment and alkali activation using Qitaihe bituminous coal as raw material,and the pore structure and chemical composition of the coal-based carbon materials are regulated by adjusting the preparation conditions and doping process.The surface morphology of the samples is observed and the pore structure parameters are analysed by SEM and BET characterisation methods;the electrochemical properties of the coal-based anode materials with different preparation conditions are tested,and the energy storage performance of the composed symmetrical supercapacitor is tested and its application potential is evaluated.The main studies are as follows:（1）Pore structure regulation and performance research of different coal-based anode materials.The specific surface area of the samples with the pyrolysis temperature of 750～950℃is 2228～2504 m~2·g^-1;the specific surface area of the samples with the pyrolysis time of2～4 h is 2461～3113 m~2·g^-1;The specific surface area of samples with a ratio of 1:3 to 1:5ranges from 2583 to 3355 m~2·g^-1.The electrochemical performance of CAC-1:4 is better.Under the current density of 1 A·g^-1,its specific capacitance is 193.6 F·g^-1.When the current density increases to 120 A·g^-1,its specific capacitance is 193.6 F·g^-1.It can still reach 150.3 F·g^-1,and the specific capacitance retention rate is 77.6%.（2）Pore structure modulation and performance study of coal-based negative electrode materials with different doping processes.The use of different dopants can lead to changes in the pore structure and the amount of heteroatom doping of the samples,and the electrochemical performance of the samples using melamine as the nitrogen source is better;the use of different doping sequences can lead to changes in the pore structure of the samples,and the electrochemical performance of the samples with heteroatom doping followed by activation is better,and the specific capacitance of CAC-NC is 220.2 F·g^-1at a current density of 1 A·g^-1.The chemical characterisation analysis shows the presence of nitrogen-containing functional groups（N-5,N-6,N-Q）on its surface.（3）The electrochemical performance and energy storage performance of CAC-NC//CAC-NC are tested,and the power density and energy density are 499.3 W·kg^-1and7.6 Wh·kg^-1at 10 A·g^-1current density,respectively.And after 10,000 charge-discharge cycles,the initial specific capacitance retention rate is 87.6%.