Single Exposed Zn (0002) Plane and Sustainable Zn-Oriented Growth Achieving Highly Reversible Zinc Metal Batteries.

ABSTRACT

To prevent dendrite growth and hydrogen evolution reaction, directional epitaxial growth of Zn2+ ions on Zn anode, especially along the lowest-surface-energy Zn (0002) plane, is pursued for highly reversible zinc metal batteries (ZMBs). However, designing single Zn (0002) exposed anodes for sustained uniaxial crystalline orientation of Zn electroplating faces challenges. Herein, we propose an anode engineering that utilizes a low lattice mismatch substrate and ordered Zn2+ migration channels to modify Zn anodes with single (0002) surface exposure and sustainable Zn-oriented growth, yielding highly reversible ZMBs. A vapor-deposited metal-organic framework Cu3(C6O6)2 film on brass foil shows low lattice mismatch (4.24 %) with electrodeposited Zn anodes, enabling the exposure of a single (0002) plane. Furthermore, the low desolvation energy (-1.36 eV) between solvated Zn2+ ions and the ordered porous Cu3(C6O6)2 film guides sustainable Zn-oriented nucleation along the Zn (0002) surface. Consequently, the Zn||Zn cells with brass-Cu3(C6O6)2 substrate shows a high average Coulombic efficiency of 99.55 % after 4,000 cycles at 10 mA cm-2. This work provides a new window to design highly reversible Zn metal anode with a single-exposed Zn (0002) plane and sustainable oriented growth for emerging ZMBs.