Spontaneous Passivation of Selective Zn (101) Plating via Dangling Bond Saturation and Electrostatic Interaction Regulation for High-Utilization, Fast-Kinetics Zinc Anodes

Abstract

Although Zn (101) exhibits faster Zn²⁺ plating/stripping kinetics and stronger bonding with Zn2+ compared to Zn (002), the application of Zn (101) in Zn batteries has been limited due to its higher reactivity with water. However, a novel approach utilizing spontaneous self-passivation of plated Zn (101) offers the potential to harness its favorable kinetics and stronger Zn-Zn bonding for battery applications. Here, we present a high-utilization and fast-kinetics Zn anode by promoting selective (101) facet growth and achieving spontaneous passivation of the underlying Zn plating. A non-stoichiometric Sn-O system is selected as the modification material because of its ability of engineering crystal structures (amorphous, rutile, layered) and manipulating electrical polarity (n-type vs p-type). The optimized SnO1.17 saturates dangling bonds of Zn (101), benefiting the preferential growth of well-aligned Zn (101) planes. Besides, the Zn2+ plating location is altered underlying the interphase due to synergetic effects of lower Zn2+ migration barriers of the layered structure and electron-blocking properties of SnO1.17. Consequently, a high Zn utilization ratio of over 91.5% is achieved for 800 hours, with an impressively low overpotential of 43 mV. Furthermore, an anode-free system combining a ZnMn2O4 cathode and a SnO1.17@Cu anode retained 81.6% capacity after 200 cycles.