A three-dimensional tunnel ion sieve interface for ultra-long life Zn metal anodes

The stable Zn metal anode is pivotal for advancing aqueous Zn-ion batteries, yet it remains challenged by rampant dendrite growth and parasitic side reactions. Herein, the spinel structured ZnV₂O₄ with moderate oxygen vacancies serves as an ion-sieve interphase on the Zn anode, whose superior selectivity of tunnel size enables a high ionic conductivity up to 10.56 mS·cm⁻¹. The surface oxygen vacancies can promote the strong adsorption towards Zn ions and subsequent desolvation. The moderate oxygen vacancy content preserves the inner integrality of connectivity tunnels for ZnV₂O₄ interphase facilitating the rapid ion transport kinetics. COMSOL simulation and density functional theory (DFT) calculation conjointly confirm the higher Zn²⁺ flux and the accelerated desolvation kinetics. Consequently, equipped with ZnV₂O₄@Zn anode, the symmetric cell delivers an ultra-stable cycling lifespan exceeding 3700 h at 4 mA·cm⁻²/1 mAh·cm⁻². Even at the condition of 8 mA·cm⁻²/1 mAh·cm⁻², the symmetric cell maintains a stable cycling for over 900 h. This work underscores the critical factor of the compatibility of oxygen vacancy and ion sieve tunnel geometry, thereby paving a promising avenue for constructing durable aqueous Zn-ion batteries.