Common-ion driven self-assembly of Cu nanoparticles for interfacial stabilization of Zn anodes

Abstract

Constructing uniform electrochemically active sites and chemically robust interphases is essential to mitigate the interfacial degradation of Zn anodes in mildly acidic electrolytes. Herein, a self-assembled Cu layer is formed on a Zn electrode via a 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 the 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, the preferential (002) orientation and the in situ formation of a Cu–Zn alloy enable 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.