Color-changing Energy Storage Dual-function Device Based On Prussian Blue Coating And Its Performance Optimization

Electrochromic glass is a kind of intelligent optical functional device that realizes stable and reversible adjustment of its optical performance by responding to external voltage changes.With this advantage,Electrochromic glass has broad applications,such as low-energy buildings,energy-saving displays,and smart stealth.The discoloration process of electrochromic devices is driven by electrochemical reactions,and the reaction mechanism and active material components are similar to the charge storage process of energy storage devices such as batteries and supercapacitors.Therefore,a new type of multifunctional electrochromic device with energy storage and color-changing functions can be developed by combining electrochromic technology with energy storage technology.In this paper,Prussian blue(PB)is used as the electrochromic material to explore the working principle,color change characteristics,electrochemical reaction behavior,and performance regulation mechanism of the dual-function device with zinc and tin anodes.Furthermore,the optical and electrochemical performance of the device is optimized.The specific research content and results of the thesis are as follows:(1)Aiming at the problem that the color change performance of Prussian blue film decays rapidly when the color change cycle in the traditional electrolyte is fast,an experimental concept of optimizing the cycle stability of the Prussian blue film by adjusting the pH of the electrolyte is proposed.First,a uniform Prussian blue(PB)electrochromic film was deposited on the surface of FTO(fluorine-doped tin oxide)glass through a hydrothermal reaction,and then the film was subjected to a cyclic voltammetric scanning test under a three-electrode system.Experiments show that when the electrolyte is acidified with HCl to pH=3,the color change cycle stability of the Prussian blue(PB)film is significantly improved.Subsequently,the Prussian blue film deposited by the hydrothermal method was used as the electrochromic electrode,Metal zinc(Zn)was used as the counter electrode,and prussian blue/zinc electrochromic energy storage dual-function device was constructed in a dual-ion electrolyte(pH=3)containing Zn²⁺and K⁺acidified by HCl.It was found that the device using acidified electrolyte can obtain a larger area capacity(46m Ah/cm²)and short coloring time(4.1s),and higher coloring efficiency(75.1cm²/C)(2)To solve the corrosion problem of the zinc anode in the acid electrolyte,this paper uses metal tin(Sn)with a higher electrode potential(-0.13 V vs.SHE)and also a large hydrogen evolution overpotential as the counter electrode to construct Prussia Blue/Sn dual-function device,and systematically investigated the electrochemical and optical properties of the device.Studies have shown that metallic tin can effectively inhibit the hydrogen evolution corrosion reaction on the metal counter electrode,thereby slowing down the performance degradation caused by it;At the same time,in the hydrochloric acid acidified electrolyte,Cl^-can act as a dissolution inhibitor of the Prussian blue film.With the above design,the cycle life of Prussian blue can be improved,and the hydrogen evolution corrosion problem of the metal counter electrode can be better solved.Prussian blue prepared by hydrothermal method was used as the positive electrode,metal tin(Sn)was used as the counter electrode,and carboxymethyl cellulose(CMC)/HCl/KCl solution are added as the electrolyte to construct a color-changing energy storage dual-function device,the device can be obtained a large area capacity(58 m Ah/m²),higher cycle life(capacity remains71%after 4000 cycles)and higher light modulation amplitude(49.3%change in light transmittance at 633 nm)when the electrolyte pH is 0.7.