Common-Ion Driven Self-Assembly of Cu Nanoparticles for Interfacial Stabilization of Zn Anodes

Abstract

Constructing uniform electrochemical-active sites and chemically robust interphases is essential to mitigate interfacial degradation of Zn anodes in mildly acidic electrolytes. Herein, a self-assembled Cu layer is formed on Zn electrode via galvanic replacement reaction driven by the reduction potential difference. Unlike conventional physical coatings, this strategy leverages a common-ion effect to finely regulate redox kinetics and control nanoparticle nucleation and growth behavior, leading to the formation of a conformal and densely packed Cu layer without the need for external energy input. This chemically guided Cu layer effectively modulates surface energy and Zn²⁺ ion flux, resulting in preferential Zn nucleation and suppresses parasitic byproduct formation. Electrochemical analyses reveal that the Cu-coated Zn anodes can improve cycling stability, with symmetric Zn||Zn cells maintaining stable operation for over 1150 hours and asymmetric Zn||Cu cells operating for more than 1800 hours at 1 mA cm⁻², with high coulombic efficiency. Moreover, preferential (002) orientation and the in situ formation of Cu−Zn alloy enable to lower nucleation barriers and promote uniform Zn deposition. This synergistic combination of structure and interfacial properties highlights a promising strategy for interfacial regulation in high-performance Zn-based energy storage systems.