Selective Adsorption of La ³⁺ Enables a Protective Layer for Dendrite-Free Zinc Anodes in Aqueous Zinc-Ion Batteries

Abstracts: Aqueous zinc-ion batteries (AZIBs) represent a promising clean energy technology thanks to their high safety, low cost, and abundant zinc reserves. However, unstable zinc anode interfaces, dendrite growth, corrosion, and hydrogen evolution side reactions limit their practical applications. This work introduces lanthanum sulfate as an effective electrolyte additive to enhance the interfacial stability and electrochemical reversibility of zinc anodes. Benefiting from the higher charge density of La 3+ than Zn 2+, La 3+ is selectively and preferentially adsorbed on the zinc anode surface, forming in situ a dense and robust inorganic protective layer. This layer physically blocks direct contact between the electrolyte and the anode, greatly suppressing corrosion and hydrogen evolution. Meanwhile, the adsorbed La 3+ regulates the interfacial electric field, directing the uniform nucleation and two-dimensional lateral deposition of Zn 2+, thus inhibiting vertical dendrite growth and tip aggregation. The Zn//Zn symmetric battery with La-ZSO electrolyte exhibits stable cycling for over 800 h in rate tests and for more than 1000 h at 1 mA cm −2, far exceeding the bare ZSO electrolyte that fails within 80 h. When paired with a sodium-doped vanadium pentoxide (NVO) cathode, the full battery delivers nearly twice the discharge capacity at 1 A g −1 . This study provides a reliable strategy for constructing dendrite-free, high-performance zinc anodes for advanced aqueous zinc-ion batteries.