Supercapacitor is an eco-friendly energy technology equipment,which has attracted a lot of attention because of its excellent stability and higher power density than electrochemical cells.Among them,the electrochemical double layer capacitor(EDLC)relies on the charge transfer between the electrolyte and the electrode surface for energy storage,so the electrode materials significantly affects the performance of capacitors.Carbon based materials play a huge role in EDLC due to their high charge storage and release characteristics.However,based on the pure double layer charge storage mechanism of carbon materials,carbon based capacitors can achieve low energy density,which is difficult to meet the high energy density requirements of the device.In this paper,carbon cloth based composite electrode materials with multiple active site and high active material loading are prepared by heteroatom doping,introduction of oxygen containing groups and design of apparent morphology based on carbon cloth,and are applied to EDLC for electrochemical performance research.The main research contents and results are as follows:(1)Firstly,through a polymerization reaction,many polypyrrole(PPy)balls are grown on the surface of carbon cloth,and then heat treated to convert them into nitrogen containing carbon balls.Finally,through electrochemical oxidation treatment,oxygen-containing groups are introduced on the surface,and an oxygen nitrogen doped carbon cloth based electrode(Q-NCS-ACC)is prepared.The experimental results show that the electrode exhibits good electrochemical performance in EDLC,providing a high area specific capacitance of 1490.4 m F·cm-2 at a current density of 1 m A·cm-2,significantly improving the electrochemical performance of the pure carbon cloth electrode.The assembled symmetrical capacitor exhibits a specific capacitance of 566.4 m F·cm-2 at 8m A·cm-2.The cycle stability test shows that after 20000 long cycles,the specific capacitance can be maintained to 96%of the initial value,showing good stability.(2)In order to improve the energy storage capacity of carbon cloth based electrode,an oxygen and nitrogen co doped carbon cloth based electrode with a core-shell structure consisting of Ni Co2O4 core and nitrogen doped carbon shell is prepared(QNC-MNW@AC).First,Ni Co2O4 nanowires are grown onto the surface of carbon cloth,and the nanowire structure increases the longitudinal specific surface area,and then increases the load of nitrogen-containing carbon layer obtained by subsequent deposition and heat treatment of polyamine(PDA).After electrochemical oxidation,surface activation and loading of oxygen containing groups are achieved.The experimental results show that the prepared electrode obtained shows a high area specific capacitance of 1794 m F·cm-2 at a current density of 1 m A·cm-2,and the assembled EDLC achieves a high energy density of 6.55 m Wh·cm-3 at a power density of 180 m W·cm-3.This preparation method provides an effective way to design high electrochemical energy storage electrodes and new generation devices.(3)In order to further improve the energy storage capacity of carbon cloth based electrodes,Ag,oxygen and nitrogen co doped carbon cloth based electrode material with porous structure and good conductivity is prepared(Ag@ONCC).Firstly,based on the oxidation-reduction reaction between PDA and Ag+,metal Ag particles and PDA layers are deposited onto the surface of carbon cloth,and then a layer of PDA is deposited to achieve high-quality loading.After that,the active composite electrode material with porous structure is prepared through heat treatment and electrochemical oxidation.The experimental results show that in a three electrode system,the electrode material can achieve an area specific capacitance of 2739.6 m F·cm-2(at a current density of 1 m A·cm-2).In a symmetrical two electrode system,when the current density is 10 m A·cm-2,the specific capacitance can reach 812.8 m F·cm-2.After 20000 cycles,the specific capacitance loss is only 12.3%,and the stability is good. |