Interfacial Reconstruction of a SnO/PVDF Coating Induced by Cycling for Stable Zn Metal Anodes

Abstract

Aqueous zinc–ion batteries are promising for safe and low-cost energy storage, but Zn metal anodes still suffer from dendritic deposition, corrosion, hydrogen evolution, and insulating by-products. Conventional protective layers can block water contact or tune surface wettability, but many static coatings gradually lose regulatory capability as the Zn/electrolyte interface evolves during repeated plating/stripping. Herein, a SnO/PVDF composite coating prepared by a doctor-blade method is developed to induce interfacial reconstruction on Zn. PVDF maintains coating continuity, while SnO provides polar Sn–O sites and, more importantly, undergoes cycling-induced chemical evolution to generate cooperative Sn and oxidized Sn–O environments (SnO and SnO2). During Zn plating/stripping, the coating evolves into a mixed Sn/SnO/SnO2-containing interphase that promotes uniform Zn nucleation, moderates local electric-field and ion-flux heterogeneity, and suppresses water-induced side reactions. Consequently, the optimized 60% SnO/PVDF-coated Zn anode shows a reduced nucleation overpotential of 16.6 mV, delivers stable Zn plating/stripping for over 2000 h under 1 mA cm−2, and over 1000 h under 5 mA cm−2. Furthermore, the full cell paired with an NH4V4O10 cathode achieves stable cycling for over 2000 cycles. This work highlights interfacial reconstruction induced by cycling as an effective strategy for stabilizing aqueous Zn metal anodes.