Interfacial dual-modulation through deoxygenation effect and tuning hydrogen-bonding environment toward highly reversible Zn metal anodes

Abstract

In aqueous zinc-ion batteries (AZIBs), the Zn anode is consistently plagued by severe corrosion reactions and dendrite growth issues, leading to rapid degradation in performance. Herein, these challenges are addressed by carbohydrazide (CBZ) additive via tuning hydrogen-bonding environment and chemical deoxygenation effect. The polar functional groups (-C=O and -NH/-NH₂) of CBZ preferentially anchor to the Zn anode and form stronger H-bonds with water molecules, which can alter Zn²⁺ migration pathways and restrain parasitic reactions associated with water molecules. Moreover, due to the unique deoxygenation effect, CBZ can react chemically with dissolved oxygen (DO) in aqueous electrolyte, thereby preventing DO from corroding the zinc metal anode and effectively suppressing surface passivation with hydrogen evolution reactions (HER). Consequently, the Zn//Zn symmetric cell with CBZ-modified electrolyte confers an extended lifespan of up to 2800 h at 5 mA cm^-2. Furthermore, the Zn//NVO pouch cell with ∼1.2 Ah capacity demonstrates excellent cycling stability.