Preparation And Electrochemical Performance Of Graphene/Carbon Aerogels

Graphene/carbon areogels used for electric double layer capacitor(EDLC) were prepared via a sol-gel process in graphene oxide (GO) solution using resorcinol(R) and formaldehyde(F) as carbon precursorThe results indicate that the structure of graphene/carbon areogels changed from agglomeration to three-dimensional cross-linked network as the pH rises. Porous carbons with the highest specific area of 513m2/g in neutral solution. The specific capacity of the carbon is 149F/g.In neutral solution, graphene/carbon areogels were prepared by solvent exchanging with acetone. The results indicate that graphene can alter the structure of porous carbons from a macroporous structure to carbon platelets, finally formed as carbon spheres. As the content of RF increases, the specific surface area increases firstly and then decreases, reaching the maximum value of 711m2/g when w(GO)/w(RF)= 1:100. Electrochemical measurements show that GO/RF-100 has the highest specific capacitance of 184F/g at the scan rate of lmV/s.Graphene/carbon areogels were prepared by freeze-drying. The trend of morphology change are similar as solvent exchanging samples. The maximum specific surface area is 1178m2/g when w(GO)/w(RF)=1:75. While GO/RF-100 has the highest specific capacitance of 169F/g, corresponding to the specific surface area is 791 m2/g. Indicate that the capacitance may be controlled not only by surface area, but pore distribution and so on.Based on above studies, it comes to a conclusion that graphene can act as nucleation and growth sites for carbon aerogels. At low mass loading level of RF, a macroporous structure was formed, and the structure of carbon aerogels originated from the sheet-structure of GO precursor. With increasing the mass of RF, RF carbon aerogel results in dispersed carbon platelets, the thickness of RF products increase along with RF mass loading. While at high mass loading levels, carbon spheres are obtained.This phenomenon has a very good application prospect in preparation of porous carbon for electric double layer capacitor because of its controllable pore structure.