An in situ self-assembled 3D zincophilic heterogeneous metal layer on a zinc metal surface for dendrite-free aqueous zinc-ion batteries

Abstract

Aqueous zinc-ion batteries (ZIBs) are extremely promising for large-scale energy storage equipment owing to their low cost, high capacity, and safety. However, severe dendrite growth during repeated plating/stripping processes restricts their further development. Herein, a 3D heterogeneous metal protective layer is formed on the Zn surface through a self-assembly chemical reaction. The in situ formed heterogeneous metal layer (HML) possesses a large specific surface area and plenty of micropores, which can not only alleviate the volume expansion during cycles, but also can ensure excellent Zn²⁺ ion transfer and regulate the uniform stripping/plating of Zn²⁺ ions. More importantly, the Zn/Sn layer with high conductivity and strong zincophilic can further reduce the nucleation barrier, inhibit dendrite formation, and decrease hydrogen evolution. As a result, Zn/Sn symmetric cells exhibit a long life of more than 900 h at 1 mA h cm⁻¹ with low voltage polarization. More impressively, Zn/Sn-CaV₆O₁₆·3H₂O full cells demonstrate significantly enhanced cycle stability (800 cycles without capacity attenuation), which is much better than that of bare zinc. This facile and scalable strategy provides a universal design for dendrite-free zinc anodes.