Preparation And Study Of Novel Tungstate-based Supercapacitor Electrode Materials

Supercapacitor is a new type of energy storage device.Its energy storage mechanism is based on Helmholtz electric double layer theory,which has attracted much attention in recent years because of its high energy density,power density and environmental friendliness.In the process of energy storage,the choice of electrode material is very important.The electrode material with larger specific surface area and rich active site will provide better electrochemical performance to the supercapacitor.Therefore,the research of supercapacitor electrode material is very important for the promotion of new energy.The development of the device is of great importance.In this paper,the transition metal tungstate supercapacitor electrode material directly grown on the collector was prepared by hydrothermal coprecipitation method,and the effect of the introduction of surfactant on the morphology and electrochemical properties of the transition metal tungstate electrode was investigated.The specific research contents are as follows:.?1?CoWO₄/ZnWO₄ supercapacitor electrode materials were prepared by hydrothermal coprecipitation method directly on the surface of the collector.The effects of surfactants on the structure and electrochemical properties of the supercapacitor electrode materials were investigated by controlling the introduction of surfactants in the preparation.The CoWO₄/ZnWO₄ electrode material with lamellar structure and feather structure were successfully prepared.The specific capacitance of the two kinds of electrode materials reached 1352.42 F g-1 and 2705.23 F g-1,respectively,at 1 A g-1 current density.The specific capacitance of electrode material with feather-like structure can be kept at about 900 F g-1 after 3000 times of cyclic charge and discharge test at a high current density of 20 A g-1,indicating that the CoWO₄/ZnWO₄ electrode materials prepared by CTAB intervention has a higher specific capacitance and more excellent cycle stability.?2?The NiWO₄/ZnWO₄ supercapacitor electrode material,which was directly grown on the surface of the collector,was successfully prepared by hydrothermal method.The introduction of CTAB makes the electrode material of this system have a more uniform cross-linked needle-like structure,scattered in the collector surface uniform and dense.This morphological change allows the material to have greater specific capacitance and better magnification characteristics.At the current density of 1A g-1,the CTAB-assisted electrode material in the preparation process has a specific capacitance of 1578.21 F g-1,which is 1.47 times of the specific capacitance of the electrode material without CTAB.Note that the addition of surfactants in this system can alter the morphology of the prepared electrode material,although it also increases the resistance of the electrode material,but the larger specific surface area,the richer active sites,and the a large number of channels due to cross-linked to make up for this shortcoming,Faraday oxidation and reduction occurred more thoroughly and comprehensively so that a greater increase in capacitance than the capacitor.?3?When the NiWO₄ / CoWO₄ supercapacitor electrode material was prepared by direct hydrothermal method,the samples without the introduction of the surfactant CTAB showed better electrochemical performance compared with the samples introduced with CTAB,and had a larger specific capacity,better magnification performance,smaller resistance,so it has a good application prospects and development potential.