Studies on transmittance modulation and ions transfer kinetic based on capacitive-controlled 2D VOinverse opal film for electrochromic energy storage application.

Two-dimensional vanadium pentoxide inverse opal (2D VOIO) architecture was fabricated by polystyrene (PS) sphere template assisted electrodeposition process. In comparison to the un-templated VOfilm, the 2D VOIO film exhibited a highly ordered hexagonal close-packed bowel-like array, as well as noticeable electrochromism, such as transmittance modulation up to 42.6% at 800 nm, high coloration efficiency (28.6 cm · C), fast ions transfer kinetic ( = 7.2 s, = 2.5 s). These improvements of electrochromic performance were attributed to the ordered morphology with larger surface areas, which considerably shortened the ions diffusion paths and accelerated ions migration. An electrochromic energy storage device assembled from the 2D VOIO film with simultaneous electrochromic and pseudocapacitive performance could not only show transmittance modulation accompanied by multicolor variations but also powered an LCD screen and an LED bulb, demonstrating a promising potential for practical applications.