Dual-mode interfacial regulation by a bifunctional additive for stable zinc anodes

Severe limitations like interface corrosion and dendritic proliferation on zinc anodes significantly restrict the practical application of aqueous zinc-ion batteries (AZIBs). Here, we introduce N-methylurea (NMU), a bifunctional electrolyte additive that concurrently regulates the electric double layer (EDL) and functions as an in situ solid electrolyte interphase (SEI) precursor. This substance has a tendency to adhere to the surfaces of zinc substrates, driving out water molecules to prevent the production of hydrogen and speed up the movement of Zn²⁺. Adsorbed N-methylurea is next electroreduced to create the situ solid electrolyte interphase, a dense organic-inorganic composite with ZnN bonding that physically separates the anode from the bulk electrolyte. This dual-protection mechanism enables the following stable electrochemical performance: a long-term lifespan of over 5500 h at a current density of 2 mA cm^-2 and more than 650 h at 20 mA cm^-2, together with a high average Coulombic efficiency (CE) of 99.5%. The present research verifies that one dual-functional electrolyte additive can tackle the persistent conflict between corrosion and dendrite formation within aqueous zinc cells synchronously, which delivers outstanding cycling stability and energy efficiency and creates an economical, feasible route for industrial scaling.