Preparation And Electricity Storage Performance Of Porous Carbon Nanosheets From Phenanthrene For Supercapacitor

As an energy storage device with excellent performance,supercapacitors not only gradually occupy a certain market,but also will have great development prospects in the future.In this paper,phenanthrene was used as a carbon source,and a high-performance porous carbon material was controllably synthesized by a template strategy coupled with physical and chemical activation method.The synthesized porous carbon materials were analyzed by trasmission electron microscopy,field emission scanning electron microscopy,and nitrogen adsorption-desorption techniques.The morphology and pore structure of the porous carbon materials were analyzed using infrared spectroscopy and Raman spectroscopy to analyze the surface functional groups and the degree of graphitization of the synthesized porous carbon materials.Cyclic voltametry,electrochemical impedance spectroscopy and galvanostatic charge and discharge methods were used to research the electrical storage performance in three-electrode system.The main conclusions are as follows:Curled porous carbon nanosheets(CPCNs)were prepared from phenanthrene a carbon source with calcium carbonate as a template and KOH as activation agent by conventional heating method.When the mass of phenanthrene,calcium carbonate,and KOH was 5 g,10 g,and 10 g,respectively,and the activation final temperature was 1173 K,the resulting material was named as CPCN1173.CPCN1173 has a large amount of curled sheet-like structure,and interconnected spatial three-dimensional structures are formed.The specific surface area,total pore volume,and average pore size of CPCN1173 are 1456 m2 g-1,3.50 cm3 g-1,and 9.61 nm,respectively.The specific capacitance of CPCN1173 is 125.0 F g-1 at a current density of 0.05 A g-1 in 6 M KOH electrolyte,while the specific capacitance retains 43.9 F g-1 at 20 A g-1.The porous carbon nanosheets were controllably synthesized from phenanthrene by conventional heating method and calcium hydroxide,calcium oxide,magnesium hydroxide and calcium carbonate temlate.When the masses of phenanthrene,magnesium hydroxide,and KOH was 5 g,10 g,and 10 g,respectively,and the activation final temperature was 1173 K,the prepared porous carbon material was named as PCMg(OH)2.The results show that PCMg(OH)2 has eccellent pore structure parameters: specific surface area up to 1823 m2 g-1,an average pore size of 2.78 nm,and a total pore volume up to 1.27 cm3 g-1.In a three-electrode system,when the current density is 0.05 A g-1,the specific capacitance of PCMg(OH)2 can reach 344.7 F g-1,and the specific capacitance of PCMg(OH)2 retains 132.7 F g-1 at 10 A g-1.Thick porous carbon nanosheets(PCs)were prepared from phenanthrene as a carbon source,calcium carbonate as a template,KOH as activation agent by conventional heating method,the resulting material was named as PCX-T(where X and T refer to the ratio of alkali to carbon and activation final temperature).In the three-electrode system,good capacitance performance was PC4-1173.When the current density was 0.05 A g-1,the specific capacitance of PC4-1173 was 338.6 F g-1,and the specific capacitance of PC4-1173 retains 155.7 F g-1 at 10 A g-1.The reason why PC4-1173 has a larger specific capacitance is because that contains more micropores and facilitates the adsorbtion of electrolyte ions.PC4-1173 has the largest BET specific surface area(SBET)and its specific surface area is 1992 m2 g-1.At the same time,the total pore volume(Vt)and micropore volume(Vmic)of the three samples are also the largest for PC4-1173,which are 1.51 cm3 g-1 and 0.286 cm3 g-1,respectively.