Preparation And Electrochemical Performance Of Polyaniline-based Supercapacitor Electrode Materials

As the electrode material of pseudocapacitor supercapacitor,polyaniline(PANI)has the advantages of high theoretical specific capacity,good chemical stability and simple preparation method,but it is a proton doping/dedoping reaction in the occurrence of redox reaction.In this process,irreversible structural changes occur in the polyaniline molecular chain,which leads to the inability of the doping/de-doping reaction to proceed smoothly,which in turn leads to the further application of the PANI electrode material rate performance and cycle stability performance.By compared PANI with other materials,the problem of poor polyaniline rate performance and cycle stability can be effectively solved.Carbon-based nanomaterials such as porous carbon materials and graphene are widely used as electrode materials for supercapacitors because of their large theoretical specific surface area,good electrical conductivity,and stable physical and chemical properties.In view of the problem of poor rate performance and cycle stability of PANI electrode materials,this paper proposes the use of cellulose-based porous carbons(C-ACs)and graphene/carboxylated nanodiamond(rGO/cND)as carriers to grow polyaniline and prepare polyaniline/cellulose-derrived porous carbons(PANI/C-ACs)and graphene/carboxylated nanodiamond@polyaniline(rGO/cND@PANI)composites.On one hand,the advantages of high specific capacity of PANI are utilized,and on the other hand,and the rate performance and cycle stability can be solved by utilize the stable and the large specific surface area of C-ACs and rGO/cND.(1)C-ACs with three-dimensional porous structure were obtained by surface activation and low-temperature carbonization of cellulose filter paper.PANI/C-ACs binary composites prepared by in-situ polymerization using C-ACs as the skeleton.PANI uniformly grows on the C-ACs skeleton to form a unique three-dimensional porous structure.Under the synergistic action of PANI and C-ACs,the composite has high specific surface area and electron conductivity,accelerates the transport of electrolyte ions,and promotes the rapid and stable surface redox reaction of PANI,thus enhancing capacitive properties of composite materials.Among them,the specific capacity of PANI/C-ACs composites at current density of 1 A/g is as high as 765 F/g,which is 105 F/g higher than pure PANI.When the current density is increased from 1 A/g to 10 A/g,the capacity retention rate is as high as 62%,which is 24% higher than pure PANI.At the same time,the capacitance retention rate was as high as 91% after 5000 cycles of charging and discharging current density of 1 A/g under two-electrode system.(2)The carboxylated nano-diamond and graphene oxide were co-reduced then the graphene/carboxylated nano-diamond(rGO/cND)composite with three-dimensional multilayer structure was obtained via intercalation of cMND.Graphene/carboxylated nanodiamond@polyaniline(rGO/cND@PANI)ternary composites were prepared by insitu polymerization using rGO/cND as carrier.On the one hand,the rGO/cND composite with three-dimensional layered structure provides more active sites for PANI growth,on the other hand,it accelerates the conduction of electrons and the transport of ions.The rGO/cND @PANI composites have a specific capacitance of 693 F/g at 1 A/g,582 F/g at 10 A/g,and a capacitance retention of 84% was obtained,which is much higher 40% than that of pure PANI.At the same time,the capacitance retention rate was as high as 90% after 2000 cycles at a current density of 5 A/g in a two-electrode system,and the capacitance retention rate under the same conditions was 12% higher than that of pure PANI.