Study On Electrochromic Supercapacitor Based On Graphene/W₁₈O₄₉ Nanocomposite And Polyaniline

Electrochromism is a phenomenon in which a device can reversibly change its optical properties when a certain applied voltage is provided.Because of this,it has been increasingly explored in the applications of smart optical displays and energy-saving smart windows.Since the energy storage is similar to the electrochromic device in terms of materials,device structure,and kinetic principles in the reaction,it can be imagined that the super capacitor and electrochromic device can be combined to produce a new multifunctional device that integrates energy storage and discoloration.It can store energy,change its optical properties,and its color can intuitively reflect the energy storage of the device in real time,that is,power visualization.This thesis focuses on the research and application of graphene/W₁₈O₄₉nanomaterials and polyaniline in electrochromic properties.The research content is as follows:1.W₁₈O₄₉nanowires and nanorods were prepared by solvothermal method and H₂pyrolysis reduction method respectively.W₁₈O₄₉nanowires have better electrochromic properties than W₁₈O₄₉nanorods.One-step reduction of graphene oxide and W₁₈O₄₉nanowires into graphene/W₁₈O₄₉nanowires?rGO-WNS?composite material was Implemented by solvothermal method.Through cyclic voltammetry?CV?and electrochemical impedance testing,it was found that the the electron transfer ability and capacitance of the composite are improved due to the addition of graphene.Therefore,compared with the single component W₁₈O₄₉nanowire,the coloring time of the composite rGO-WNS electrode was shortened from 10 s to 2 s,and the bleaching time was shortened from 7 s to 4 s.The coloration efficiency is 52.72 cm-²·C^-1.2.Polyaniline?PANI?film was prepared by electrochemical polymerization.The best conditions for the preparation of PANI film were obtained from the CV chart and the charge and discharge curve?GCD?,that is,the PANI film performance reached the optimal when the voltage was 0-1.3V and the rate of 50 m V/s was cycled for 4 times.3.rGO-WNS and PANI are assembled into electrochromic supercapacitors,where rGO-WNS is a cathode electrochromic material and PANI is an anode electrochromic material.The two materials are electrochemically matched and the electrolyte solutions are similar.rGO-WNS is used as the negative electrode in the supercapacitor,it is in a colored state when charging,and is bleached during discharge;PANI shows the opposite situation.In the supercapacitor,PANI is used as a positive electrode,and PANI is colored when charged,and bleached during discharge.It can be seen from the GCD graph that when the current density is 0.2 m A cm^-2,the area specific capacitance of the device is 13.98 m F·cm^-2.In the process of charging and discharging,the device gradually changes from the original light green to dark green,then to dark blue,and then back to the original light green,the coloring efficiency is 76.37 cm^-2·C^-1,this multi-functional device with rich color changes can allow people to directly observe the energy status of the device,has a good application prospect.