Studies On Synthesis And Electrochemical Properties Of Graphene Composite Aerogel

As one of the most promising electrochemical energy storage devices,supercapacitors have attracted intense interest owing to their high efficiency energy-storage and long cycle life.Graphene attracts much attention because of its large theoretical surfacearea,low density,extraordinary electrical conductivity and excellent mechanical stability.The true capacity of graphene is largely limited by agglomeration of graphene sheets.As a consequence,the graphene aerogel with 3D porous network structure has been assembled to prevent GO sheets from collapsing.Incorporating transition metal oxide and conducting polymer with graphene aerogel to fabricate graphene composite aerogel.Here,self-assembled hydrothermal method was used to prepare the graphene-based composite aerogel by combining graphene with MnO₂ and PANI.The morphology and structure were characterized by a series of techniques such as FTIR,XRD,BET and SEM.When as the working electrode,its electrochemical properties were studied.The specific work content and achievements are as follows:?1?Incorporating MnO₂ with RGO to fabricate MnO₂/RGO composite aerogel.The microstructure of MnO₂/RGO composite aerogel was analyzed by SEM,BET and other tests,and it was found that the MnO₂/RGO composite aerogel maintained porous structure.Electrochemical performance tests showed that the MnO₂/RGO composite aerogel had the specific capacity of 252 F/g at a current density of 1 A/g and even 146F/g at a high rate of 40 A/g.The capacity retention rate was 57.9%.The capacitance has remained 87.8%after 10000 cycles at a current density of 20 A/g.?2?MnO₂/P-RGO composite aerogel prepared by modifying MnO₂/RGO with phytic acid?PA?retained the 3D porous network structure.The introduction of PA reduces the particle size of MnO2 and improves the dispersion of MnO2 particles.Electrochemical performance tests showed that the MnO₂/P-RGO composite aerogel could achieve the specific capacitance of 645 F/g under the current density of 1 A/g and 410 F/g at a high rate of 40 A/g.The capacity retention rate was 63.6%.The capacitance has remained 91.8%after 10000 cycles at a current density of 20 A/g.?3?MnO₂/S-PANI/P-RGO composite aerogel was prepared by modifying MnO2/P-RGO with solvent-free polyaniline?S-PANI?.The microstructure of MnO2/S-PANI/P-RGO composite aerogel was analyzed by SEM,BET and other tests,and it was found that the MnO₂/S-PANI/P-RGO composite aerogel maintains the 3D porous structure.The introduction of S-PANI enhances the conductivity and reduces the ion diffusion impedance of MnO₂/S-PANI/P-RGO composite aerogel.Electrochemical performance tests showed that the MnO₂/S-PANI/P-RGO composite exhibited the specific capacitance of 571 F/g at a current density of 1 A/g and even 413 F/g at a high current density of 40 A/g.The capacity retention rate was 72.6%,showing a good rate capability.The MnO₂/S-PANI/P-RGO composite aerogel exhibited remarkable long-term stability,96.2% of the initial capacitance after 10,000 cycles under the high current density of 20 A/g.