Sabatier Principle Inspired Bifunctional Alloy Interface for Stable and High-Depth Discharging Zinc Metal Anodes

Abstract

Achieving stable Zn anodes is essential for advancing high-performance Zn metal batteries. Here, we propose a Sabatier principle inspired bifunctional transition-metal (TM) interface to enable homogeneous Zn dissolution during discharging and dendrite-free Zn deposition during charging. Among various TM-coated Zn (TM@Zn) electrodes, Cu@Zn exhibits the highest reversibility and structural stability, attributed to the optimal interaction between Cu and Zn. The heteroatomic interaction-dependent electrochemical performance parallels the Sabatier principle. Morphological analyses reveal that bare Zn anodes display detrimental etching pits during stripping, which is different from the uniform dissolution for Cu@Zn electrodes. During subsequent plating, the conductive interface serves as a secondary current collector for uniform Zn deposition in Cu@Zn, thus demonstrating a bifunctional nature. Atomic observations disclose the working mechanisms of this interface as a gradual phase transition from Cu to CuZn5 during cycling. The Cu@Zn anodes exhibit an ultralong cycling lifespan of over 8000 h at a low current of 1 mA cm-2 and over 250 h at a high depth of discharge of 80%. They also demonstrate practical feasibility by maintaining 88.7% capacity retention after 1000 cycles in Cu@Zn||VO2 full cells. This work provides new insights into the Sabatier chemistry inspired bifunctional layers for Zn metal battery system.