Controllable Synthesis Of Hierarchical Porous Carbon Materials By Hard Templates For Supercapacitor Electrode

Supercapacitor is one of the energy storage device,which has the characteristics of ultra-high capacitance,high power density,fast charge/discharge speed,long cycle life,safety and environmental protection.It has a broad application prospect in a variety of portable electronic devices,electric vehicles and other fields.The electrode materials mainly cause its performance.In this thesis,hierarchical porous carbon materials,hierarchical porous nitrogen-doped carbon materials and porous carbon/poly?o-phenylenediamine?composites were synthesized by hard template method and used as supercapacitor electrode materials.The relationship between structure and properties of these materials was explored.The main contents and results are as follows:Porous carbon materials were synthesized using basic zinc carbonate?BZC?and potassium carbonate?PC?as reaction hard template and activator respectively.The effects of carbon-containing precursors,carbonization temperature and the proportion of precursors on the structure and properties of the samples were investigated.When glucose?G?is used as carbon precursor and the mass ratio of precursor,reaction hard template and activator is 2:1:1,the sample HPC?G-BZC-PC?has micro-mesoporous hierarchical pore structure,high specific surface area,high degree of graphitization and no heteroatom doping.In the test of 6m KOH button battery,the specific capacitance reaches 241.1 F/g(at 1 A g^-1),even if the current density increases to 20A/g,it has a good rate performance?86.2%?.After 10000 charge-discharge cycles,it still maintains an initial capacitance of 97.1%,showing good cycle stability.In addition,in the neutral electrolyte test,the potential range is broadened and the energy density of the capacitor is increased to12.0 Wh/Kg?400 W/Kg?.Using the above preparation method,a series of nitrogen doped samples?N-HPCs?were synthesized by adding N dopant.The effects of dopant,doping ratio and the type of reaction hard template on the structure and properties of the samples were investigated.When BZC is used as hard template,urea?U?is used as dopant,and the mass ratio of precursor,reaction hard template and activator is 2:1:2:2,the synthesized N-HPC?G/U-BZC-PC?has rich coral-like morphology,micro-mesoporous hierarchical pore structure and high specific surface area.N doping increases the specific capacitance of supercapacitor electrode material to 301.9F/g?1 A/g?,and still has good rate performance?10 A/g,89.4%?and cycle stability?98.1%after 10000 times?.A series of composites?N-HPC/PoPD?were prepared by in-situ oxidative polymerization of nitrogen-doped N-HPC?G/U-BZC-PC?and o-phenylenediamine?oPD?.The effects of composite ratio and the type of oxidant on the structure and electrochemical properties of the materials were investigated.The sample N-HPC/PoPD?1:1?synthesized with FeCl₃ as oxidant and the mass ratio of N-HPC to oPD at 1:1 showed the highest electrochemical performance.Under the three-electrode system test,the specific capacitance reaches 679 F/g?1 A/g?and the rate performance is 81.6%?up to 10 A/g?.Under the button battery test,the specific capacitance is as high as 441 F/g,and the rate performance is 86.6%.It has the potential to be used as a supercapacitor electrode material.At the same time,a series of composites?N-MC/PoPD?were synthesized by using self-synthesized ordered mesoporous carbon N-MC instead of N-HPC.The specific capacitance of the three-electrode system was only 229.3 F/g?1 A/g?.