Design of Highly Stable Binder-Free Sn–Al Sol Coating for Zinc Metal Anode

The construction of artificial solid electrolyte interfaces on zinc anodes is recognized as an effective strategy to mitigate zinc dendrite formation and side reactions; however, existing methods are often complex and time-consuming. In this study, we successfully fabricated a highly stable Sn-Al sol protective layer on the surface of the zinc anode using a simple spray-coating technique. This protective layer significantly enhances the electrochemical performance of zinc symmetric cells, achieving stable cycling for over 2500 h at 1 mA cm^-2. In Zn//Cu half-cells, the Sn-Al sol coating improves charge-discharge efficiency and cycling stability, with over 500 and 950 cycles at 1 and 5 mA cm^-2, respectively. The average charge-discharge efficiency during stable cycling reaches 95.7%, in contrast to 85.0% for bare Zn, indicating improved utilization of Zn²⁺. Additionally, the Sn-Al sol coating offers enhanced corrosion resistance and effectively promotes uniform Zn²⁺ growth along the (101) crystal plane, reducing dendrite formation. Overall, this simple spray-coating approach presents significant potential for high-stability modifications of zinc anodes, offering a novel strategy for the industrial application of zinc-ion batteries.