Preparation Of Electrodes Based On Commercial Filter Paper And Construction Of Flexible Devices

With the rapid development of various flexible electronics,the demand for electronic products and wearable technology are growing substantially.Supercapacitors have received tremendous attentions in view of its fast charge-discharge rate,long cycling stability and high power density.Exploration of flexible supercapacitor electrodes with high capacity,low cost and long life remains a big challenge.In this thesis,the commercially available filter paper was used as the flexible substrate onto which the highly conductive material poly(3,4-ethylene dioxythiophene)(PEDOT)was coated in order to improve the conductivity of hybrid electrode.In the following section,the capacity of P-PEDOT was enhanced by growing pseudocapacitive FeOH nanoflakes by electrodeposition.The main contents in the thesis includes the following:In chapter III,with the commercial filter paper as the substrate,an oxidative polymerization was used to prepare conductive PEDOT on the surface of cellulose fibers.The conductivity of filter paper was improved dramatically.Our results show that the conductivity of as-prepared P-PEDOT hybrid electrode achieves 625 S m-1,and it can be bent into any shapes without obvious decrease of conductivity,showing good connection of PEDOT to the cellulose which also improve the mechanical strength of the overall electrode.The electrochemical measurement of the P-PEDOT in a standard three-electrode cell shows that that its specific areal capacitance is 132 mF cm-2(110 F g-1)in 1 M aqueous H2SO4 electrolyte.As the current density increases from 2 to 10 mA cm-2,the capacitance of P-PEDOT does not drop obviously.After 10000 cycle at 10 mA cm-2,the capacitance retention rate is 89%.A flexible supercapacitor built with the P-PEDOT as electrode and PVA/H2SO4 as the solid-state electrolyte shows an areal capacitance of 31 mF cm-2,an energy density of 0.08 mWh cm-3and power density of 144 mW cm-3.Moreover,the capacitor exhibits a good rate capability with 82%capacitance retention upon increasing the current density from 0.1 to 1 mA Cm-2.In chapter ?,the above mentioned P-PEDOT was used as conductive substrate to grow FeOOH nanoflakes using a constant current electrodeposition method.The mass loading of the FeOOH on P-PEDOT can be controlled simply by changing the electrodeposition time.The structure of FeOOH was characterized by SEM,XPS,XRD and elemental mapping.Results from electrochemical characterization shows that the growth of the FeOOH can dramatically enhance the areal capacitance of P-PEDOT up to 1287 mF cm-2(785 F g-1).Although the FeOOH on P-PEDOT are uniform,the rate performance of P-PEDOT-FeOOH is still poor,which is only 46%as the current density increases from 5 to 15 mA cm-2.