1：Experimental Design and Method Selection:

The study employed a soft chemistry aqueous route for synthesis, using pH adjustment and hydrothermal conditions. Structural characterization involved XRD, TEM, SEM, STEM, and spectroscopic methods. Electrochemical properties were evaluated using a three-electrode cell setup.

2：Sample Selection and Data Sources:

Samples were synthesized from sodium tungstate dihydrate and hydrazine in water, with pH adjusted to 0.6. Data were obtained from laboratory experiments and computational modeling (DFT).

3：Data were obtained from laboratory experiments and computational modeling (DFT). List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included PanAlytical X’Pert Pro diffractometer, Hitachi S3400-N SEM, Tecnai spirit G2 TEM, JEOL JEMARM200cF STEM, Perkin Elmer Lambda 900 UV/Vis/NIR spectrometer, Omicron XPS apparatus, Bruker X-band ESR spectrometer, Mettler LF1600 TGA/DTA, BEL Belsorp Max and Belprep II for sorption, Solartron Modilab potentiostat. Materials included Na2WO4·2H2O, hydrazine, HCl, ethanol, FTO substrates, H2SO4 electrolyte.

4：Experimental Procedures and Operational Workflow:

Synthesis involved dissolving Na2WO4·2H2O in water, adding hydrazine, adjusting pH to 0.6 with HCl, aging, heating at 120°C for 12h, washing, and drying. Characterization steps included XRD for structure resolution, microscopy for nanostructure imaging, spectroscopy for optical and electronic properties, and electrochemical testing for electrochromic performance.

5：6 with HCl, aging, heating at 120°C for 12h, washing, and drying. Characterization steps included XRD for structure resolution, microscopy for nanostructure imaging, spectroscopy for optical and electronic properties, and electrochemical testing for electrochromic performance. Data Analysis Methods:

5. Data Analysis Methods: Data were analyzed using Rietveld refinement for XRD, DFT calculations for electronic structure, and standard electrochemical and spectroscopic techniques for property evaluation.