Preparation And Performance Study Of TiO₂ Nanoarrays Composite Electrode Materials For Supercapacitors

Supercapacitor is a new type of energy storage devices,with ultra power density,long cycle life,good cycle stability,and environmental friendly,etc.Electrode material quality directly affects the performance of supercapacitor performance,and therefore much attention has been paid to the development and application of new type of electrode materials research.Due to the performance of electrode materials is affected by its material properties and surface state,can make use of surface modification to form core-shell structure or exotic atoms doping and increase the quantity of oxygen concentration to materials,and improve the electrochemical performance of material.In this paper,the preparation of one dimensional core-shell structure of TiO2 nanorods arrays and Mo doped W18O49 nanofibers(W18O49-Mo)as the research object,to carry out the material preparation process optimization,explore its applications as electrode materials for supercapacitors.First of all.The TiO2 nanorods array was preparation on conductive glass FTO by hydrothermal synthesis method,investigation on oxygen content in the electrolyte effect on electrochemical performance of the array.Secondly,the TiO2 nanorods array as a skeleton,using hydrothermal method,glucose as carbon source,through high temperature carbonization,preparation of TiO2@C core-shell structure of nanorods array.On this base,WCl6 used as tungsten source,aimed at the preparation of TiO2@C@WO3 nanorods array.The result show that when the concentration of glucose solution of 0.01 M,TiO2@C@WO3 nanorods array showed the best electrochemical performance.Under the scan rate of 8 mV/s,the specific capacitance of TiO2,TiO2@C and TiO2@C@WO3 nanorods array are 2.53,4.582 and 8.63 mF·cm-2,respectively.Na2WO4·2H2O as tungsten source,different morphology of WO3 nanomaterial were prepared by adding different structure oriented agent and the concentration of hydrochloric acid.The growth mechanism of W18O49-Mo nanofibers prepared by hydrothermal method was further explored,the structure and microstructure of the samples were analyzed by the X-ray powder diffraction,scanning electron microscope(SEM).Furthermore,Na2MoO4·2H2O as molybdate source,samples were prepared by control the Mo/W ratio and reaction time.The results show that the morphology of samples transform gather nanosheet to nanofibers;When the Mo/W=1 and reaction time is 2 h,as-prepared one-dimension W18O49-Mo nanofibers has a good electrochemical performance with specific capacitance of 723.3 F g"1 and the specific capacitance remained 84.8%after 2 000 times cycle;The asymmetric supercapacitor W18O49-Mo//AC was assembled by W18O49-Mo nanofibers and active carbon(AC),with a 0-1.5 V.wording voltage window,energy density of 26.2 Wh-kg-1 ans power density of 375 W-kg-1.Due to the one-dimension structure can provided directional transmission channel for electro transfer,Mo ato doping at the same time,increased the oxygen vacancy concentration,the number of active sites and W6+ in W18O49 structure,improved the conductivity and electrochemical of materials.