In situ construction of a static-dynamic hybrid interface toward stable Zn anodes for aqueous Zn-ion batteries

Abstract

Aqueous Zn-ion batteries are promising candidates for next-generation energy storage devices due to the advantages of high safety, low cost and good environmental friendliness. However, the uncontrollable dendrite growth and undesirable side reactions occurring on the Zn anode result in poor cycling stability. Herein, a Lewis base, triethanolamine, is used as the electrolyte additive to construct a hybrid solid-electrolyte interphase layer composed of a static ZnSO₄·3Zn(OH)₂·4H₂O layer and dynamic quaternary ammonium ion adsorption layer. The static SEI layer acts as a physical barrier between the Zn anode and electrolyte, thus effectively suppressing chemical corrosion and the hydrogen evolution reaction. The dynamic layer can not only regulate the ion flux at the interface, but also promote the de-solvation of solvated Zn²⁺, thus leading to homogenous Zn deposition along the (002) electro-crystallization orientation. As a result, the Zn anode demonstrates an extended cycle life of 2500 h at a current density of 1.0 mA cm⁻², with an areal capacity of 1.0 mA h cm⁻² and a high coulombic efficiency (CE) of 98.94%. The Zn‖V₂O₅ cells exhibit a specific capacity of 178.4 mA h g⁻¹ after 500 cycles, indicating both high capacity and robust cycling stability, which are essential for practical applications.