Preparation Of Cork-derived Porous Activated Carbon And The Research Of Electrochemical Properties

Biomass is widely used in the preparation of biomass carbon materiall owing to its wide sources,low cost and sustainable utilization.As-prepared biomass carbon materials possess the terrific application prospect in supercapacitors.There are a large amount of waste biomass produced in human production and living,annually.The waste biomass are mostly handled in the form of the landfill and incineration disposal,bringing about the waste of resources and environmental pollution.Waste biomass can be converted to carbon materials,which not only make use of resources rationally and improve the efficiency of resource utilization,but also protect the environment.In this paper,the waste material from cork products production was used as the precursor.Different preparation technologies were adopted to prepare cork-derived porous activated carbon with different structural characteristics and electrochemical performance of samples were studied.?1?Using the raw cork as precursor,the cork based porous activated carbon with suitable pore structure were prepared by activation of KOH at 800 ? after carbonization at 600 ?.The texture of as-prepared porous activated carbon have been conducted by N₂ adsorption method,scanning electron microscopy?SEM?,X-ray diffraction?XRD?and surface element analysis?XPS?.The capacitive property of the carbons was tested in different electrolyte systems.As a result,the obtained cork-derived porous activated carbon is a kind of thin sheet structure,and the highest specific surface area and pore volume were obtained at the alkali/carbon mass ratio of 4.5,which is 2313 m2/g and 1.28 cm3/g,severally.In three electrode system of KOH,the sample CO AC-4.5 exhibited a high specific capacitance of 296 F/g at 0.1 A/g.In 6 M KOH electrolyte,the assembled COAC-4.5//COAC-4.5 symmetric supercapacitor showed a little capacitance reduction of 0.5%after 5000 cycles,indicating a good electrochemical stability.In 1 M Na2S04 electrolyte,the symmetric supercapacitor displayed a good rate performance of 80.5%retention from 0.5 A/g?174 F/g?to 50 A/g?140 F/g?and a high energy density of 19.62 W h/kg.?2?The oxidation-reduction method of KMnO4 was used in this paper.The cork was mixed with KMnO₄ by certain proportion.The dry mixture obtained was carbonized at different carbonization temperature to prepare the cork based porous activated carbon with 3D hierarchical porous structure.The texture of Cork-derived hierarchical porous carbon have been conducted by N₂ adsorption method,scanning electron microscopy?SEM?,X-ray diffraction?XRD?and surface element analysis?XPS?.The capacitive property of the carbons was tested in different electrolyte systems.As a result,the obtained activated carbon possesses a 3D hierarchical porous structure.In all samples,the sample CHPC-600 prepared at 600? exhibits the best electrochemical performance,and its the specific surface area and pore volume is 689 m2/g and 0.96 cm/g,severally.In three electrode system of KOH,the sample CHPC-600 exhibited a high capacitance of 290 F/g at a 0.2 A/g.In 6 M KOH electrolyte,the assembled CHPC-600//CHPC-600 symmetric supercapacitor showed a a little capacitance reduction of 4.8%after 10000 cycles,indicating a good electrochemical stability.In 1 M Na2S04 electrolyte,the symmetric supercapacitor displayed a good rate performance of 89.7%retention from 1 A/g?165 F/g?to 10 A/g?148 F/g?and a high energy density of 14.7 W h/kg.