Syntheses And Electrochemcal Capacitive Performance Of CNFs/Co₃O₄@PANI Composites

Supercapacitor?also known as electrochemical capacitor?,with fast charge and discharge,long cycle life,high power output,no maintenance and so on,is a new type of electrochemical energy storage devices.As an important part of electrochemical capacitors,electrode materials are the key to improve the performances of supercapacitors.Cobalt tetroxide?Co₃O₄?gets people's high attentions because of its low cost,green,theoretical high capacity and so on.But it has the shortcomings of poor electrical conductivity,easy to reunion,resistance and so on.Polyaniline?PANI?as developed the emerging conductive material in recent years,have the advantages of good electrical conductivity,high capacitance,environmental and so on.In addition to its poor cycle stability,it is a good carbon coating material.The use of carbon nanofibers?CNFs?as a matrix can not only reduce the use of insulating adhesives but also can promote the diffusion of electrolyte and electron transport.Therefore,we can composite three materials using the synergies to improve electrode material performances.In this paper,the following research work is carried out on the preparation,morphology and electrochemical properties of Co₃O₄/CNFs electrode materials with different morphologies and CNFs/Co₃O₄@PANI composite electrode materials.?1?Changing the ratio of raw materials and reaction temperature,Co₃O₄/CNFs electrode materials with various nanomorphology were prepared by hydrothermal reaction.The morphology of the materials were analyzed by SEM and the electrochemical performances were studied.And the results show that Co₃O₄/CNFs nanowires electrode materials have good capacitance.The results show that Co₃O₄/CNFs nanowires electrode materials have good capacitance characteristics.The specific capacitance of Co₃O₄/CNFs nanowire electrode material is668.6 F/g at 1 A/g,and the specific capacitance is 399.5 F/g when the current density reaches 20 A/ g.So the specific capacitance is 59.8%.?2?CNFs/Co₃O₄@PANI composite electrode materials were prepared by electropolymerization of Co₃O₄/CNFs nanowires and polyaniline using carbon nanofibers as matrix materials.The morphology of the composites was analyzed by XRD? SEM and Raman.The electrochemical properties exhibited in two electrolyte were studied.It was found that the specific capacitance of CNFs/Co₃O₄@PANI composites was 1246 F/g at 1 A/ g.When the current density reaches 20 A/ g,the specific capacitance is 59.8%.And the specific retention was 85% after 1000 cycles.