| WO3 is the most widely studied inorganic electrochromic material,and it is usually used to prepare the core electrode layer of electrochromic devices.Under the action of an applied voltage,double injection/extraction of electrons and ions can be achieved to change its color.However,its limited ionic capacity and electronic conductivity greatly limit the further improvement and application of WO3 electrochemical performance.Designing and constructing nanostructures is a common material modification method.It can effectively increase the contact area between the material surface and the electrolyte and provide more active sites for ion insertion,thereby improving the electrochemical performance of the material.On the other hand,with the increasing energy consumption in modern society and the more serious environmental pollution,the development of new energy storage devices has gradually attracted attention in recent years.Pseudocapacitive devices are the most commonly used electrochemical energy storage devices,which share similar device structures,active materials and working mechanisms with electrochromic devices.Therefore,they can be organically combined to develop new bifunctional integrated devices.This integrated device can be used as an energy storage device,and its energy storage state can be monitored at any time according to the color change.This thesis focuses on the preparation and properties of WO3 nanostructure and its application in electrochromic energy storage devices,aiming to prepare high-performance electrochromic energy storage devices by optimizing the properties of electrode materials and device structures.The main research contents and results are as follows:(1)Preparation and electrochromic properties of WO3 nanostructured films based on magnetron sputtering technology.In this study,WO3 nanoparticle seed layer films were prepared on indium-doped tin oxide(ITO)glass substrates by co-sputtering of Ag target and W target.On this basis,Gd-doped WO3 nanowire films were grown by sputtering using a Gd sheet placed on a W target.The best WO3 nanowire films were obtained at a Gd doping concentration of 0.49 at.%.Compared with the pure WO3 film,the nanowire film exhibited enhanced optical modulation at 633 nm(?T=52.7%),high coloring efficiency(87.3 cm~2 C-1),high diffusion coefficient(95.2×10-11 cm~2/s)and excellent cycling stability(capacitance retention of 87.4%after 1000 cycles).In addition,the WO3 nanowire films exhibited excellent charge storage capacity with a maximum areal capacitance of 8.44 m F cm-2 under galvanostatic charge and discharge of 0.4 m A.Through the film structure characterization and electrochemical analysis,it can be seen that the improvement of its performance is attributed to the increased specific surface area of the WO3 nanowire film,which reduces the ion diffusion distance.And the nanostructure ensures sufficient contact with the electrolyte.(2)Design and fabrication of an electrochromic energy storage device.In this study,Ni O films were prepared by magnetron sputtering as the counter electrode,and 1 mol/L Li Cl O4/PC solution was used as the electrolyte to obtain an electrochromic energy storage device with high charge storage capacity by encapsulation technology.The device gradually changed from a transparent state to a dark blue state during charging,and then gradually changed from a dark blue state to a transparent state during discharging.This device can continuously supply power to a LED,and its energy storage state can be easily assessed by visually observing the color change of the device. |
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