Research On The Integrated Fabrication And Performance Of Photoelectrochromic Energy Storage Device

In modern buildings,energy consumption issues such as window components and electronic device display screens have received extensive attention.At present,electrochromic devices(ECD)have been proposed and widely developed as smart windows,but they still need to be charged and discolored by an external power source,which greatly increases the installation cost and complexity of the devices.The photoelectrochromic supercapacitor(PESC)is a new type of photoelectrochromic energy storage device that combines optoelectronic function and electrochromic(EC),which can solve the output power problem of photovoltaic devices by storing electrical energy and controlling the energy output.The energy state of the device can also be reflected by the change in color.Therefore,it is of great significance to design and manufacture PESC with simple structure,excellent electrochemical performance,variable working modes,and energy storage function.In this paper,by designing metal oxides,sulfides,polymers and their composite materials with different structures as electrode materials,and selecting electrolytes with different states to prepare PESC with both electricity storage and electrochromic functions.The main research contents and results are as follows:(1)Porous tungsten trioxide(WO₃)thin films were prepared by the sol-gel method,and used as electrode materials to fabricate symmetric supercapacitors.The specific capacitance of the electrochromic supercapacitor(ESC)is 69.9 m F cm^-2 at a scan speed of5 m V s^-1 under a voltage window of 0?1 V.ESC and dye-sensitized solar cells(DSSC)were assembled into a multi-mode PESC based on H⁺tungsten-based aqueous electrolyte,and the photoelectrochemical performance of the device was tested.The device has a high spectral modulation amplitude and exhibits a specific capacitance of 72 F m^-2 after photocharging,which is higher than that of discrete symmetric devices assembled by an electrochemical workstation.It not only shows excellent electrochromic function,but also has good excellent energy storage effect and very stable cycling performance.(2)Polyvinyl alcohol/sulfuric acid(PVA/H₂SO₄)gels were prepared and used as electrolytes for ESC.The gel-electrolyte-based ESC had the functions of adjusting brightness,temperature,and energy storage,and exhibited good cycling stability.After3000 cycles of charge and discharge test,the capacity retention rate was 90%.At the same time,tungsten sulfide-tungsten trioxide(WS₂-WO₃)was used as the counter electrode of DSSC,and the gel electrolyte-based ESC and DSSC were assembled into a complementary semi-solid integrated PESC.The integrated device can not only convert and store solar energy into electricity,but also modulate UV-visible and near-infrared light transmittance.The specific capacitance reached 200.2 m F cm^-2 after photocharging.(3)The composite material of WO₃ and polyaniline(PANI)was prepared by the continuous ionic layer adsorption reaction(SILAR)method,and the WO₃@PANI double-layer electrochromic layer was used as the electrode material to prepare the double-layer ESC.After electrochemical testing,the ESC obtained an area specific capacitance of 46.3 m F cm^-2 and a capacity retention rate of 85%after 3000 cycles.The photocharging voltage of the bilayer PESC composed of bilayer ESC and DSSC can reach0.58 V.The double-layer PESC obtained an area specific capacitance of 147.8 m F cm^-2 at the current density of 0.1 m A cm^-2.It can display different colors according to different voltages,which shows the diversity of its electrochromic phenomenon.