Simultaneous tailoring of hydrogen evolution and dendrite growth via a fertilizer-derived additive for the stabilization of the zinc anode interface

Abstract

Zinc metal anodes suffer from unavoidable issues related to their charge–discharge stability (mainly inducing uneven dendrite formation and unwanted side reactions between the electrode and electrolyte), which lead to their inferior reversibility and hinder their commercial applications. Optimizing the nucleation behavior to improve reversible Zn electrodeposition has been extensively studied, but the poor cycling reversibility and additive cost remain challenging. Herein, an additive engineering approach using fertilizer-derived N-methylthiourea was designed to regulate the Zn-electrolyte interface while avoiding these problems. This sulfur-carrying urea molecule has a strong affinity for both Zn and Zn²⁺, and it preferentially adsorbs on the Zn surface to delay water adsorption and controls the secondary diffusion of Zn²⁺ to stabilize the Zn/electrolyte interface, extending the hydrogen evolution potential to −0.92 V. It also prolongs the induction time of Zn crystal formation, leading to uniform Zn plating/stripping as well as dendrite formation suppression. Consequently, the electrochemical performance was greatly improved in the Zn|Zn symmetric cell, showing a low overvoltage (40 mV) and stable cycling performance (1000 h) at 1 mA cm⁻². Further, the Zn|V₂O₅–C full-cell delivered a consistent capacity over 420 cycles with a coulombic efficiency of ∼98.6%. This study demonstrates a new strategy for metal–electrolyte interface stabilization that can be applied to practical metal-based batteries.