Abstract:

The core-shell structured VO₂（M）@SiO₂ materials can be prepared by sol-gel method aiming to significantly enhance their visible light transmittance（T_lum） and effectively slow down the oxidation process of VO₂（M）.It has significant implications for enhancing the application value of smart windows.While the Stöber method was a traditional approach for fabricating VO₂（M）@SiO₂ core-shell structures，the sol-gel method was used to simplify the preparation process，reduce production cost，and minimize process control factors.Preliminary investigations on the silica sol-gel experiment were conducted to explore the process parameters for silica sol gelation and verify the feasibility of silica sol-gel coating on VO₂（M）.The research results demonstrated that the optimal gelation capacity of the silica sol was achieved with a pH value of 5~6 and a solid content of 15%~20%.Additionally，the gelation time was shortened with the increase of gelation temperature，and the crystallinity and thermal stability of SiO₂ powder obtained after roasting were increased.Dense and stable core-shell structured VO₂（M）@SiO₂ materials were successfully synthesized using the optimized process parameters for silica sol-gel.The coating coverage reached 93.3%，and the transmittance of the thin film was improved to 65%.Furthermore，the phase transition temperature of the material was decreased，and the hysteresis loop width was narrowed.Therefore，the sol-gel method with silica sol provided a simplified and cost-effective approach for preparing highly performance core-shell structured VO₂（M）@SiO₂ materials，holding significant potential for applications such as smart windows.

Key words: sol-gel method using silica sol, coating, core-shell structure, VO₂（M）@SiO₂ materials