Preparation And Performance Study Of Carbon-based Metal Oxide/hydroxide Electrode Materials

With the development of smart textiles and wearable electronic devices,flexible supercapacitors are considered to be the most competitive energy-storage devices which have the advantages of high power density,good flexibility,low cost and environmental protection.Therefore,the lightweight and high-performance flexible electrode materials have attracted much attention of researchers.In this paper,the carbon cloth was used as the conductive flexible substrate,then the nickel-cobalt double hydroxides(NiCo-DH)and iron oxides grown on the carbon cloth which were fabricated through the hydrothermal synthesis process.The binder-free electrodes for supercapacitors were prepared by combining the good electrical conductivity and better cycle stability of carbon cloth with the high specific capacitance of metal oxides/hydroxides.The properties of the electrodes have been studied,and the specific research contents are summarized up as follows:(1)The one-step hydrothermal synthesis method was used for fabricating the nickel-cobalt double hydroxides on carbon cloth,and the effect of different concentration of Ni2+ and Co2+ in the intial reactant on microstructure and electrochemical performance were studied.The results showed that flake-like structure grown intact gradually and uniformly on carbon cloth under the concentration of Ni2+=4 mmol,Co2+=8 mmol,which has the best electrochemical properties.The C-Ni-4-Co-8 electrode displayed the high specific capacitance of 4.19 F cm-2 at the current density of 5 mA cm-2 and excellent rate capability of 62%even at the high current density of 100 mA cm-2.The capacitance retention of electrode was up to 83%after charge/discharge 5000 cycles at 35 mA cm-2,which demonstrated the high specific capacitance and excellent electrochemical stability of the C-Ni-4-Co-8 electrode.(2)The Fe2O3 grown on the flexible carbon cloth was synthesized by hydrothermal method.Simultaneously,the morphology and electrochemical properties of the electrode materials which prepared at different hydrothermal temperatures were investigated.The results displayed that the optimum conditions for Fe2O3 growth were obtained when the hydrothermal temperature was 180? and the Fe2O3/CC-180 electrode showed the best electrochemical performance.The areal capacity reached 1.06 F cm-2 at the current density of 1 mA cm-2,and it also displayed good rate capability about 62%when the current density increases by 20 times.In addition,the specific capacitance of the electrode was only about 5%less than that of the original capacitance after charge/discharge 2000 cycles at the current density of 8 mA cm-2.The Fe2O3/CC-180 electrode exhibited high specific capacitance and remarkable cycle stability,which indicated that the electrode was a kind of supercapacitor anode material with research value.