Preparation And Electrochemical Performance Of Sheet-like Porous Carbon Oriented By Graphene Oxide

Energy and environment is the key to sustainable development of the society.As a new generation of energy storage device,owning to the quick charging and discharging speed,high power density,good cycle performance,environmental and etc.,supercapacitors have been attracted much attention.The three-dimensional materials are widely used in the supercapacitor because of the advantages of high specific surface area,good conductivity and well electron transportation performance.Graphene oxide(GO),formaldehyde(F)and resorcinol(R)were used as raw materials.And the three-dimensional carbon/reduced graphene oxide composite nanosheets(CGSs)were constructed via a wet-chemistry reaction.Then,the 3-D carbon/reduced of graphene oxide nanosheets with hierarchical pore structure were synthesized from prepared CGSs by chemical activation using KOH.The morphology,specific surface area and pore structure of products were analyzed by SEM,TEM,XRD,Raman,XPS,N2 absorption/desorption.The constant current charge-discharge(GCD),cyclic voltammograms(CV)and electrochemical impedance spectrogram(EIS)test were utilized to characterize the electrochemical performances of samples.The idiographic works are summarized as follows:1,Three-dimensional carbon/graphene oxide/carbon nanosheets was synthesized in a wet-chemistry synthesis system.During the preparation progress,formaldehyde resorcinol resin was used as carbon source and graphene oxide was used as shape orientation regent.The influence of the ratio of raw materials on the morphology and the electrochemical performance of the materials were investigated.When the mass ratio of GO,R and F was 3:50:34,the as-prepared sandwich like nanosheets had a thin thickness of 17 nm and a high specific area of 352 m2/g.At a current density of 1A/g,CGSs had a specific capacity of 173.8 F/g.The CGSs with tunable thickness were prepared by changing the mass ratio of GO and RF-resin.Thicker samples increase the electron transfer distance and the electrolyte ion transfer resistance,resulting in poor electrochemical performance.2,3D carbon/reduced of graphene oxide nanosheets with hierarchical porous structure were synthesized from prepared CGSs by chemical activation using KOH.The effects of the mass ratio for CGSs/KOH and activation temperature on the structure and electrochemical properties of the materials were discussed.The results showed that the sample activated at 600 ℃ with the mass ratio of 1:1 had the optimal performances.The optimal sample had a high specific surface area of 690 m2/g,a high specific capacitance of 224 F/g at 1 A/g,and an excellent cycle life with 99.2% capacitance retention after 8000 cycles at the high current density of 5 A/g.