Design、preparation And Performance Of Polyaniline-based Electrode Materials For Supercapacitors

Polyaniline（PANI）is a typical conductive polymer.When used as an electrode material,it is widely used in supercapacitors because of its excellent pseudocapacitance properties.By adding special dopants,high-performance PANI electrode materials with special morphology can be prepared.After compounding PANI and graphene,the energy density of the device can be effectively improved through the construction of strong interaction.When PANI is used as the electrode material,it can exhibit outstanding electrochemical performance in asymmetric supercapacitors.This paper introduces the doping mechanism,conductivity mechanism,different preparation methods and applications of PANI in supercapacitors.Based on the PANI,starting from the morphology design of the polyaniline electrode itself,constructing stable interactions between polyaniline and inorganic materials and the efficient construction of asymmetric supercapacitors three methods were used to prepare PANI electrode materials with excellent electrochemical performance.First,2,2`-[（1,1`-biphenyl）-4,4`-diyldi-2,1-ethylenediyl]bisbenzenesulfonic acid disodium salt（CBS-X）was used as a dopant under acidic conditions,a feather fan-like PANI electrode material composed of connected at the ends was synthesized.The special morphology of polyaniline was verified by SEM and TEM,and the structure of the material was characterized by FTIR and UV-vis.The formation mechanism of the special morphology of PANI was discussed,and its influence on the electrochemical performance of PANI was deeply studied.The results show that the feather fan-like of PANI can significantly improve the electrolyte ion transport and can effectively resist the volume change of the polymer chain during the long-term charge and discharge cycle.The prepared PANI/CBS-X electrode has a maximum specific capacitance of 403.5 F/g at a current density of 0.5A/g,and the electrochemical stability is significantly improved.Secondly,select 4-aminophenyl modified graphene（GNS-NH2）as the copolymerization template of aniline,p-phenylenediamine and triphenylamine monomer.Through stable interaction built between the graphene substrate and the polymer,and between the polymer chain and the polymer chain,it not only provides a larger delocalized orbit for the carrier,but also improves the stability of the material during electrolyte ions embedding/disembedding.X-ray photoelectron spectroscopy was used to verify the modification of the 4-aminophenyl on the surface of graphene and the successful preparation of the composite material.The composite electrode has a specific capacitance value of1701.1 F/g at a sweep speed of 5 mV/s.The solid supercapacitor assembled with this electrode material has a power density of 50 W/kg and can increase the energy density to 15.3 Wh/kg.After 5000electrochemical cycles,it showed a specific capacitance retention rate of 94.9%.The above data provides strong data support for the practical application of PANI composite materials in supercapacitors.Finally,the electrochemical polymerization method was used to prepare a polyaniline flexible electrode with regular morphology on the carbon cloth substrate by adjusting the polymerization sweep speed and polymerization time.The electrode and the MoS₂ electrode prepared by the solvothermal method are assembled into a flexible asymmetric supercapacitor.The elemental composition confirmed the successful preparation of the two electrode materials.The two electrode materials have specific capacitance values of 423.4 F/g（5 mV/s）and 1538 F/g（5 mV/s）,respectively,and both can retain more than 98%of the specific capacitance after 5000 cycles.The assembled supercapacitors showed good flexibility,the specific capacitance retention rate reached 85.5%after5000 cycles,the energy density of the supercapacitors reaches 17.2 Wh/kg at a power density of 100W/kg,which strongly proves that PANI has great application potential in flexible supercapacitors.