Hierarchically Porous Carbon Materials:Study On The Dual-activator Optimization Synthesis And The Performances For Capacitor

With the rapid growth of global energy consumption and the huge loss of traditional fossil energy,human health,energy security and global environment are facing serious challenges.Therefore,there is an urgent need to develop environmentally friendly and high-performance energy storage and conversion equipment.Electric Double-Layer Capacitors?EDLCs?have attracted extensive attention of researchers because of their advantages of fast charge-discharge speed,high power density and cycle efficiency and so on.However,EDLCs still have the problem of low energy density(usually less than 6 W h kg^-1),which limits its application.Thus it is necessary to find the materials with large specific surface area,which are conducive to charge storage as EDLCs electrode materials in order to improve the electrochemical storage performance.Porous carbon materials are considered as one of the most valuable materials for EDLCs electrode materials because of their abundant pores,high surface modifiability,large specific surface area,adjustable pore size,wide source and low cost.The synthesis process plays an important role in the surface morphology,pore size distribution,graphitization degree,active site defect degree and surface functional group composition for porous carbon materials.Based on this,this paper focuses on the optimization of preparation for hierarchically porous carbon materials by dual-porogen method and the performances for hierarchically porous carbon materials capacitors.?1?Study on the preparation of hierarchically porous carbon materials by C₃N₃Na₃S₃/KOH dual-porogen method and their supercapacitor performances.Porous carbon materials with the abundant micropore,mesoporous and macropore are synthesized by using trisodium thiocyanate?C₃N₃Na₃S₃?and potassium hydroxide?KOH?as the dual porogens and egg yolk as carbon source,showing excellent supercapacitor performances.The results show that the supercapacitor assembled with sample ETK-700-1 has excellent performances.In 1 mol L^-1 H₂SO₄electrolyte,the specific capacitance is 549 F g^-1 at the current density of 1 A g^-1,288.6 F g^-1 at the current density of 30 A g^-1,and the capacitance retention rate is 96.3%?1000 cycles?and 94.5%?10000 cycles?,respectively.In the two-electrode system,the power density can reach 6007.7 W kg^-1 and the energy density can reach 12.7 W h kg^-1.?2?Study on the preparation of hierarchically porous carbon materials by C₃H₆N₆/KOH dual-porogen method and their supercapacitor performances.Using melamine?C₃H₆N₆?and KOH as dual porogens,Lycium barbarum as the biomass precursor,hierarchically porous carbon materials with abundant pore structure are prepared by carbonization and activation at high temperature.LMK-700-1 exhibits the high specific surface area(3343.80 m² g^-1),and high specific capacitance(520.0 F g^-1,291.0 F g^-1)in three-electrode system at 1 A g^-1 and 30 A g^-1 in 1 mol L^-1 H₂SO₄ electrolyte,respectively.The capacitance retention rates are 97.8%?1,000 cycles?and 96.8%?10,000 cycles?,respectively.Under the two-electrode system,the energy density can reach 12.5 W h kg^-1 at 0.5 A g^-1 and the power density can reach 5304.6 W kg^-1 at 30 A g^-1.?3?Study on the preparation of hierarchically porous carbon materials by C₁₀H₁₄N₂Na₂O₈/KOH dual-porogen method and their supercapacitor performances.The hierarchically porous carbon material?WDK-700-1?with high electrochemical properties are prepared by using edetate disodium(C₁₀H₁₄N₂Na₂O₈)and KOH as the dual porogens,and using walnut shell as carbon source,which is easily available and cheap.By adjusting the mass ratio of activating agents and activation temperature to optimize the synthesis conditions,the prepared materials assembled into supercapacitors have the excellent specific capacitance(557.8 F g^-1 at 1 A g^-1 and 291.0 F g^-11 at 30 A g^-1 in1 mol L^-1 H₂SO₄ electrolyte).The structure,composition and electrochemical properties of porous carbon materials are investigated by means of a series of structure characterization and electrochemical techniques.The results show that the porous carbon sample has reasonable pore size distribution,high specific surface area,excellent specific capacitance,excellent cycle stability and high power density and energy density,promoting the directive synthesis and screening of high energy storage materials for electrochemical capacitors.