Preparation Of Metal Oxide/poly(5-formylindole) Nanocomposites And Investigation Of Its Electrochromic-Supercapacitive Properties

The nanocomposites of conducting polymer and metal oxide can combine with the good electrochromic properties of conducting polymer and the excellent supercapacitivepropertiesofmetaloxide.Basedonthis,an electrochromic-supercapacitor difunctional device with multi-color changes,high coloring efficiency,short response time,large storage power and long device life will be designed.The development of the difunctional device will be an effective strategy to realize the intelligent application of supercapacitors.In this paper,three different kinds of nanocomposites based on conducting polymer poly?5-formylindole??P5FIn?with different morphology of metal oxides were successfully prepared:Nickel oxide/polypoly?5-formylindole??NiO/P5FIn?,Manganesedioxide/poly?5-formylindole??MnO₂/P5FIn?andTungstenoxide/poly?5-formylindole??WO₃/P5FIn?.Based on the above metal oxide/poly?5-formylindole?nanocomposites,three kinds of high performance electrochromic-supercapacitors are constructed.The electrochemical properties,electrochromic properties and capacitance properties of the composite films and its devices were tested.1.NiO with nanoflakes morphology was prepared by hydrothermal method on the transparent conducting glass of FTO.On this basis,P5FIn was electrochemically polymerized by cyclic voltammetry,and the composite film of NiO/P5FIn was obtained.The electrochemical properties of the film were characterized,and it was found that the polymer film with better redox activity and electrical conductivity may be caused by the synergistic effect of two monomers.At 495 nm,the maximum light contrast of NiO/P5FIn composite film was 13.45%with the response time of 3.70 s.NiO/P5FIn composite film had reversible transformation between yellow and brown.When the charging current density was 0.2 mA cm^-2,the specific capacitance value of NiO/P5FIncompositefilmwas35.37mFcm^-2.Nickeloxide/poly poly?5-formylindole?//poly?3,4-polyethylenethiophene??NiO/P5FIn//PEDOT?electrochromic-supercapacitor was prepared based on NiO/P5FIn nanocomposite.The NiO/P5FIn//PEDOT device can change from light green to dark green,and the energy storage can be monitored by the color change.When the charging current density was0.02 mA cm^-2,the specific capacitance value of NiO/P5FIn//PEDOT device was 2.37mF cm^-2.The result of charge and discharge stability test showed that NiO/P5FIn//PEDOT device had good electrochemical stability.After 1000 cycles,the specific capacitance remained 97%of the inital value.2.MnO₂ with nanorods morphology was prepared by hydrothermal method on FTO electrode.P5FIn was grown by cyclic voltammetry on this substrate,and MnO₂/P5FIn nanostructure composite were obtained.The prepared MnO₂/P5FIn nanocomposite film had good redox activity and its stability,which was better than P5FIn and MnO₂.The electrochromic properties of MnO₂/P5FIn nanocomposite film were studied,and the results showed that the nanocomposite film can be reversibly transformed between yellow and green.At 493 nm,the response time of MnO₂/P5FIn nanocomposite film was 4.65 s.The supercapacitive properties of MnO₂/P5FIn nanocomposite film was characterized by charge-discharge test.When the charging current density was 0.1 mA cm^-2,the specific capacitance value of MnO₂/P5FIn nanocompositefilmwas22.65mFcm^-2.MnO₂/P5FIn//PEDOT electrochromic-supercapacitor was built based on MnO₂/P5FIn nanocomposite.MnO₂/P5FIn//PEDOT device can change from light brown to dark green,and the energy storage can be monitored by the color change.When the charge and discharge currentdensitywas1.0mAcm^-2,thespecificcapacitancevalueof MnO₂/P5FIn//PEDOT device was 10.83 mF cm^-2.After 1000 cycles of charge-discharge test,the specific capacitance of MnO₂/P5FIn//PEDOT device remained 97%,which showed that MnO₂/P5FIn//PEDOT device had good energy storage capacity and electrochromic properties.3.WO₃ with nanoflakes morphology was prepared by hydrothermal method on FTO electrode.P5FIn was grown by cyclic voltammetry method to obtain the nanostructure composite film of WO₃/P5FIn.The impedance value of WO₃/P5FIn nanocomposite was 8?.The WO₃/P5FIn nanocomposite film can be reversibly transformed from dark green-yellow-light green.The optical contrast was 45%at 745nm.The response time from the oxidation state to the reduced state was 4.75 s and the response time from the reduced state to the oxidation state was still 4.75 s.When the charging current density was 0.1 mA cm^-2,the specific capacitance value of WO₃/P5FInnanocompositefilmwas34.13mFcm^-2.Thesymmetry electrochromic-supercapacitor based on WO₃/P5FIn nanocomposite was prepared.WO₃/P5FIn//WO₃/P5FIn device can change from light green to dark green.When the charge and discharge current density was 0.025 mA cm^-2,the specific capacitance value of WO₃/P5FIn//WO₃/P5FIn device was 1.97 mF cm^-2.After 1000electrochemical cycles,the device still had good electrochemical activity,and its specific capacitance can remain 96.7%of the inital value.