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.