1. Top-view SEM images of coralline V₂O₅ nanorod architecture (a), digital photos of coralline V₂O₅ architecture under different voltages (b), SEM images of SnO₂/V₂O₅ films (c), color parameters (Lab color mode) and optical images of SnO₂/V₂O₅ films at different working states (d), cross-sectional SEM image of the ITO/WO₃/Ta₂O₅/Li/V₂O₅/ITO ECD (Electrochromic Device) (e), digital photos of the ECD in the bleached and colored state (f), schematic illustration of a large-scale Zn-SVO electrochromic display showing three intrinsic colors (g), and digital photographs of the large-scale Zn-SVO display under different voltage bias conditions (h)^{[17,18,19,20]}

2. Color effects recorded at a 60° angle for cathodic coloration (yellow stack) and anodic coloration (green stack) of an orange-red 7 double-layer nanoparticle NiO/WO₃ stack (a), and electrochromic properties of dense WO₃ film and 4-bilayer electrochromic distributed Bragg reflectors with various Bragg wavelength (b) (λ_B=450, 550, 650 nm)^[22,23]

3. Color gallery obtained from F-P nanocavity-type electrochromic electrode at different applied potentials^[24]

4. Scheme and photographs of the two-electrode electrochromic cell (a), digital images of the film during coloration (5-30 s) and bleaching process (1-3 s) (b)^[25,26,27]

5. Schematic diagram of ECD structure (a) and infrared reflectance spectra (b)^[35]

6. Spectral emittance of ECD (a) and infrared optical photograph (b)^[40]

7. Schematic diagrams of ECD structures (a, b) and infrared reflectance spectra with different crystalline WO₃ (c-e)^[42]

8. Cross-sectional SEM image of the ECD (a) and visible-to-infrared spectral emittance (b)^[43]

9. Schematic drawing of graphene device (a), schematic representation of working principle of the graphene device (b), thermal camera images of device under the voltage bias of 0 and 3 V, respectively (c, d)^[44]

10. Crystal structures of Li₄Ti₅O₁₂ and Li₇Ti₅O₁₂ (a), visible-to-infrared spectral reflectance (b), photograph (top) and thermograph (bottom) in the two states (c)^[45]