Pseudocapacitive porous amorphous vanadium pentoxide with enhanced multicolored electrochromism

Development of high-performance transparent multicolored electrochromic (EC) materials is crucial for promoting the EC technology for see-through displays and sunglasses. Here, we report a photochemical method for accessing macroporous amorphous vanadium pentoxide (a-V2O5) films with enhanced EC performance for multicolored transparent EC devices. By tracking the composition and morphology evolution of precursor film under UV irradiation, we propose a bubble-templating mechanism to elucidate the formation of macropores in the a-V2O5. The amorphous phase combined with the macroporosity endow the V2O5 films with significantly enhanced multicolored EC performance, which can be attributed to the surface pseudocapacitive mechanism. The pseudocapacitive EC process exhibits faster electrochemical kinetics, higher charge capacity, and less structural destruction to the films than the conventional diffusion-controlled ion insertion/extraction electrochromism, leading to enhanced response times, color palettes, and cycling stability. The high-performance a-V2O5 films enable the fabrication of multicolored see-through EC devices that demonstrate promising application for sun-glasses.