A Facile Strategy To Construct Au@VxO2x+1 Nanoflowers as a Multicolor Electrochromic Material for Adaptive Camouflage

Transition metal oxides (TMOs) are promising inorganic electrochromic materials (ECMs) that can be widely used in electronic displays and adaptive camouflage. However, there are still huge challenges for TMOs to simultaneously achieve multicolor transformation capability and good cycling stability. Herein, we assemble Au-modified (0.01 wt %) VxO2x+1 (x > 2) nanoflowers (Au@VxO2x+1 NFs) composed of two-dimensional porous nanosheets containing two valences states of vanadium (V4+ and V5+). The Au@VxO2x+1 NFs exhibits outstanding electrochromic performance with five reversible color transformations (orange, yellow, green, gray, and blue) at a voltage less than 1.5 V and excellent cycling stability (2000 cycles without significant decay). To the best of our knowledge, this is the first time that a single vanadium oxide ECM, rather than a device, realizes five color changes. This work provides a feasible way for the efficient preparation of multicolor electrochromic TMOs. The newly developed Au@VxO2x+1 NFs demonstrate the potential application in adaptive camouflage.