Study On The Preparation And Electrochemical Performance Of Humic Acids Based Sphericalporous Carbon

Humic acids?HAs?as a chain of amphiphilic biomass precursor with more than 40wt%carbon contentand abundant functional groupscould be well-dispersed in aqueous or KOH solution,which can organize into nano-scale contact.The cheap and environmental-friendly carbon precursor with abundant production will be quite advantageous if applied for preparation of porous carbon materials.In this paper,the effects of morphology and particle size distribution of porous carbon on the electrochemical properties were studied systematically by using purified LFA as carbon precursors.By using the facile method of solvent evaporation,the porous carbon microbeads?PCM?have been successfully prepared at ambient pressure,and their channels were regulated by carbonization and KOH activation.Meanwhile,the difference of electrochemical behavior between spherical activated carbon and powdered activated carbon was also compared.The results showed that the sample exhibited remarkable improvement in textural properties and conductivity,and displayed excellent capacitive performances.The porous carbon materials electrodes with the "porous core structure" behaved superior specific capacitances of 320 F g^-1 at a current density of 0.05 A g^-1 in 6 M KOH electrolyte,which could still remain 193 F g^-1 when the current density increased to 100 A g^-1.Remarkably,in the 1 M TEABF₄/PC electrolyte,the PCM samples could reach 156 F g^-1 at 0.05 A g^-1,and possess a outstanding energy density of 39.50 Wh kg^-1 and maintain at 22.05 Wh kg^-1even the power density rised up to 5880 W kg^-1.The balance of structural characteristic and high performance,makes the porous carbon microbeads be a kind of competitive and promising supercapacitor electrode materials.In addition,combined with the excellent electrochemical performance of spherical carbon,we further constructed nano-carbon aerogels with three-dimensional skeleton structure,and explored the effect of spherical particle size on electrochemical behavior.The spherical nanoparticles can effectively reduce the distance of ion transport,and the stability of the carbon skeleton can further enhance the electrochemical cycling stability.The PCAs₂ sample exhibits a superior high specific capacitance of 368 F g^-1 at a current density of 0.05 A g^-1 in 6 M KOH electrolyte.The sample also has outstanding cycling stability with capacitance retention of 98.4%after10,000 cycles at a current density of 100 A g^-1.