Fig.1 Reported distribution of transition metal oxide electrochromic materials

Fig.2 Changes in crystal form, crystal plane orientation, and space group of WO3 with temperature variation[16]

Fig.3 Nano morphologies of various WO3 prepared by different preparation methods

Fig.4 (a) The proportion of various inorganic material papers in the field of electrochromism; (b) The trend of the number of published papers on tungsten based compounds in the field of electrochromism from 2014 to 2024

Fig.5 Common preparation methods of tungstate nanomaterials

Fig.6 (a) Transmittance curves of Li doped NWO and WO3 films at 300—1500 nm; (b) Transmittance curves of the device at 300—1000 nm under different biases; (c) Transmittance curves of the device at 300—1500 nm after being left to stand for different periods of time; (d) Time variation curve of device charge density with the number of cycles; (e) The variation curve of the device CV curve with the number of cycles; (f) The variation curve of device transmittance with the number of cycles at 300—1000 nm[81]

Fig.7 (a) Crystal structure of hexagonal sodium tungsten bronze; (b) Transmission electron microscopy image of sodium tungsten bronze; (c) Transmission spectra of sodium tungsten bronze in bleached and colored states (digital photo attached); (d) XRD patterns of sodium tungsten bronze in bleached and colored states; (e) Fourier transform infrared spectra of sodium tungsten bronze in bleached and colored states[19]

Fig.8 (a) Schematic diagram of H2W2O7, WO3·H2O, and WO3 structures; (b) CV curves at scanning speeds of 50, 100, 200, 500, and 1000 mV·s-1; (c) Scanning electron microscopy image of H2W2O7; (d) In situ Raman spectroscopy curve of H2W2O7; (e) Digital photos collected during in situ Raman spectroscopy of H2W2O7[89]

Fig.9 (a) Crystal structure of Cs3W11O35; (b) Transmittance and reflectance curves of Cs3W11O35 with different layers; (c) Transmission electron microscopy image of Cs3W11O35; (d) Visible and infrared images for thermal shielding test[94]

Fig.10 (a) Schematic diagram of WO3 structure; (b) Schematic diagram of Nb18W16O93 structure; (c) Schematic diagram of Nb2O5 structure; (d) CV curve at a scanning speed of 20 mV·s-1; (e) In situ transmittance voltage curve at 633 nm; (f) Transmittance curve of 300—1600 nm (corresponding photo in the illustration); (g) In situ transmittance curve with a square wave potential applied at 633 nm; (h) Transmittance curves at different voltages; (i) Coloring efficiency at 633 nm[39]

Fig.11 (a) Transmittance curves of Ce4W9O33 electrode under different applied potentials; (b) Electrochromic photo of Ce4W9O33 electrode; (c) Solar irradiation spectra of Ce4W9O33 electrode under different applied potentials; (d) In situ transmittance curve with a square wave potential applied at 633 nm; (e) In situ transmittance curve with a square wave potential applied at 1200 nm; (f) The cycling performance of Ce4W9O33 electrode[40]