Step-Edge Guided Homoepitaxy Enables Highly Reversible Zn Plating/Stripping

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Hostless metal anodes are crucial for high-energy-density batteries but suffer from disordered plating and dendrite formation, limiting battery life.
• Disordered plating in metal anodes leads to side reactions, anisotropy, and ultimately, battery failure due to dendrite and void formation.

Purpose of the Study:

• To develop a method for ordered metal plating and stripping in rechargeable batteries.
• To overcome the limitations of disordered plating in hostless metal anodes.
• To enhance the Coulombic efficiency and cycle life of zinc metal batteries.

Main Methods:

• Engineered atomic terrace height on mono-oriented Zn(0002) foil anodes.
• Utilized step-edge guided homoepitaxy for controlled zinc deposition.
• Investigated in-plane and out-of-plane epitaxy through favored edge nucleation and interfacial energy minimization.

Main Results:

• Achieved ordered, layer-by-layer zinc plating and stripping regardless of charging conditions.
• Demonstrated electrochemical homoepitaxy of continuous Zn(0002) crystals with near-theoretical density.
• Attained 99.8% Coulombic efficiency, high depths of discharge (51% and 82%), and extended battery lifetimes.

Conclusions:

• Step-edge guided homoepitaxy enables reversible and ordered metal plating/stripping.
• This breakthrough offers new insights into intrinsic metal plating mechanisms for advanced batteries.
• The developed method significantly improves the performance and longevity of zinc metal batteries.