Steel Anti‐Corrosion Strategy Enables Long‐Cycle Zn Anode

Abstract The progress of aqueous zinc batteries (AZBs) is limited by the poor cycling life due to Zn anode instability, including dendrite growth, surface corrosion, and passivation. Inspired by the anti‐corrosion strategy of steel industry, a compounding corrosion inhibitor (CCI) is employed as the electrolyte additive for Zn metal anode protection. It is shown that CCI can spontaneously generate a uniform and ≈30 nm thick solid‐electrolyte interphase (SEI) layer on Zn anode with a strong adhesion via ZnO bonding. This SEI layer efficiently prohibits water corrosion and guides homogeneous Zn deposition without obvious dendrite formation. This enables reversible Zn deposition and dissolution for over 1100 h under the condition of 1 mA cm −2 and 1 mAh cm −2 in symmetric cells. The Zn‐MnO 2 full cells with CCI‐modified electrolyte deliver an ultralow capacity decay rate (0.013% per cycle) at 0.5 A g −1 over 1000 cycles. Such an innovative strategy paves a low‐cost way to achieve AZBs with long lifespan.