One-step Preparation Of Manganese Dioxide Polyaniline Electrode Material And Supercapacitor Performance

Supercapacitors have the characteristics of high power density,long cycle life,fast charge and discharge rates,etc.And it have attracted widespread attention in energy storage.There are many types of electrode materials for supercapacitors,including carbonaceous materials,metal oxides and conductive polymers.Among metal oxides,manganese dioxide?MnO₂?is favored for its advantages such as simple synthesis,rich resources,non-toxicity,good cycle stability,large specific surface area,environmental friendliness,and high theoretical specific capacitance.However,its decomposition in the acid electrolyte and its own poor electrical conductivity severely limit its application in supercapacitors.Therefore,compounding MnO₂ with polyaniline?PANI?,which has high electrical conductivity and good redox reversibility,can effectively overcome the defects of MnO₂.While PANI protects MnO₂,MnO₂ can also provide support for PANI,limiting its volume expansion and contraction,thereby improving the cycle stability of the electrode material.Therefore,in this paper,the two materials are combined to prepare a composite material that can fully utilize the advantages of each material and overcome the defects of a single material.Among many preparation methods,the redox method is a commonly used method,which is relatively easy to implement in the laboratory and industry.However,due to the electrostatic interaction between the product particles and the existence of non-bridged hydroxyl groups in the product gel,a large number of product particles are easily stacked together,agglomeration occurs,and the structural advantage of the product is lost.This article solves the problem of agglomeration by adding surfactants.In this paper,a manganese dioxide/polyaniline composite electrode was prepared in one step by a redox method.In the preparation process,by adding a surfactant to control the micro-morphology of the composite material,the optimal ratio of manganese dioxide and polyaniline composite was discussed.And the influence of different types of surfactants on the electrochemical performance of the prepared MnO₂/PANI composites,and the scanning electron microscope,transmission electron microscope,cyclic voltammetry,electrochemical AC impedance and other methods were used to characterize and test them.The manganese dioxide/polyaniline composite electrode prepared with sodium dodecyl sulfate?SDS?as a surfactant has significantly improved electrochemical performance.Aniline has a positive charge and attracts each other with anionic surfactants to control its shape.Appearance and improve its electrochemical performance.By changing the design ratio of PANI:?MnO₂/PANI?,the composite material with the best performance was obtained.When the ratio of PANI:?MnO₂/PANI?is 70%,and the current density is 0.5A/g,the specific capacitances of the electrodes without SDS and SDS manganese dioxide/polyaniline composite materials are respectively 108.4 F/g and 533.7 F/g.Different types of surfactants were selected in the experiment,namely non-ionic surfactant polyvinyl pyrrolidone?PVP?,cationic surfactant cetyl trimethyl ammonium bromide?CTAB?,and anionic surfactant twelve.Sodium alkyl sulfate?SDS?was used for experiments with a PANI:?MnO₂/PANI?ratio of 70%.The test results show that non-ionic surfactants and cationic surfactants do not control the morphology of the composites well,and have poor electrochemical performance.When the current density is 1 A/g,the specific capacitances are respectively 267F/g and 125 F/g.While the anionic surfactant has a good effect on the morphology of the composite,the electrochemical performance is significantly improved,the current density is 1 A/g,and the specific capacitance is 427 F/g.