Preparation And Electrochemical Performance Of Polyaniline/Graphene Composites

Supercapacitor is a kind of energy storage and conversion device,is widely used in various fields,due to its high power density,long cycle life and other significant advantages.Active materials are key parts of the supercapacitor,play a decisive role in the performance of supercapacitors,and therefore attract widespread attentions.Due to the excellent physical and chemical properties of graphene,graphene-based electrode materials are the current hotspots.However,because of the accumulation of graphene,graphene-based electrode materials are usually resulting in poor performance.Preparation of binary composites by combining with the conductive polymer can not only effectively inhibit the accumulation of graphene,but also introduce high pseudocapacitance to composites,significantly enhance the electrochemical performance of materials,is an effective pathway to prepare high-performance graphene-based electrode materials.In the present work,PANI/RGO composite electrode materials were prepared by a continuous in-situ polymerization-hydrothermal reduction two-step method,and the solubility of aniline and polyaniline in the reaction system was improved by adding isopropanol to the reactants.The effects of isopropanol on the composites were investigated by physical characterization and electrochemical analysis.The results show that the introduction of isopropanol can not only enhance the doping level and oxidation degree of PANI in the composites,but also increase the nitrogen content of RGO,and affect the pore structure and stability of the composites additionally.Electrochemical studies have shown that the introduction of isopropanol can enhance the conductivity of the composite material,thereby enhancing the electrochemical properties of the composite.The effect of the amount of isopropanol on the electrochemical properties of the composites was also studied.It was found that when the volume ratio of isopropanol was 1/3,the composite showed the best electrochemical performance.The composite provides a maximum specific capacitance(729.4 F g^-1,0.5 A g^-1)and a good rate performance（64.2%）,is a high-performance electrode material.In addition,some similar alcohols were used to prepare composites instead of isopropanol,and electrochemical studies have shown that similar alcohols also had a similar effect on the electrochemical performance of composite materials,but their enhancement effects were weaker than isopropanol,and the differences may come from their stronger molecular polarities.To further enhance the electrochemical performance of the composites,PANI/MWCNTs/RGO ternary composites were prepared by introduce a small amount of hydrophilic MWCNTs prepared by a one-step hydrothermal method,and the effects of the hydrophilicity of MWCNTs on the electrochemical performance of the ternary composites were investigated.The results show that the better the hydrophilicity of MWCNTs is,the easier it is to disperse in the reaction solvent,then the smaller the impedance of the composites is,therefore the higher the conductivity is,and the better the rate performance is.Through the introduction of hydrophilic MWCNTs,the composite material can achieve a maximum rate performance retention of 84.2%,and the enhancement effect is very significant.