Preparation Of Porous Carbon Materials Derived From Organic Polymer And Its Application In Supercapacitors

The problems of energy shortage and environmental pollution increased greatly due to the rapid development of economy.The development of clean and efficient new energy to achieve carbon neutralization as soon as possible has become an important goal.Supercapacitors have attracted the attention of many researchers because of their fast charge and discharge and high energy density.One of the keys to improve supercapacitors is to find electrode materials with better performance.Porous carbon material is one of the directions of electrode material worth exploring and studying.The preparation methods of porous carbon materials can be divided into template-free method and template method.And the selection of carbonization precursors including natural biomass materials and synthetic materials is an important factor.In this thesis,a relatively rare porous polymer was used as the precursor,potassium hydroxide was used as the activator,and the new porous carbon material was prepared by template-free carbonization as the electrode material of supercapacitor.Then the specific capacitance performance of the material was tested by electrochemical workstation and Raman,BET and other characterization methods were applied to explore the reasons for the excellent performance of the material.Firstly,organic polymers were synthesized by solvothermal method,and then activated and carbonized the precursors with different materials and different ways.The synthesize and operate conditions of the supercapacitors were optimized to obtain the best properties of the porous carbon materials as excellent as possible.After a series of electrochemical performance tests,the results show that the highest specific capacitance of the material can reach 294 F/g at the current density of 1 A/g,and the maximum specific capacitance can reach 334 F/g at the current density of 0.1 A/g.The specific area of the carbon is 1843 m~2/g when carbonization temperature is 800℃.The capacitance retention rate is as high as 97.2%after 1000 cycles in the current density of 2 A/g.The material was characterized by scanning electron microscope,Raman spectroscopy and other instruments to find out the reason of its better specific capacitance performance in the view of material structures.Secondly,the porous polymer based on biphenyl was synthesized by solvothermal method,which made the structure of carbonization precursor more regular and symmetrical.After that,the specific capacitance performance of the product is optimized by optimizing the carbonization temperature,the proportion of materials and activators,etc.When the mass ratio of precursor to activator is 1:3,and the carbonization temperature is 800℃,the specific area of the material will reach to1419.2 m~2/g.The capacitance performance of the material reaches the best value of350 F/g at the current density of 1 A/g.After 1000 cycles,the capacity retention rate is 98.2%.Finally,the structure and morphology were also explored to investigate the reasons of good electrochemical performance.After carbonization,the meso-pores increased significantly which could enhance the conductivity of the material.