In‐Situ Solid Electrolyte Interface via Dual Reaction Strategy for Highly Reversible Zinc Anode

In‐situ construction of solid electrolyte interfaces (SEI) is an effective strategy to enhance the reversibility of zinc (Zn) anodes. However, in‐situ SEI to afford high reversibility under high current density conditions (≥ 20 mA cm−2) is highly desired yet extremely challenging. Herein, we propose a dual reaction strategy of spontaneous electrostatic reaction and electrochemical decomposition for the in‐situ construction of SEI, which is composed of organic‐rich upper layer and inorganic‐rich inner layer. Particularly, in‐situ SEI performs as “growth binder" at small current density and “orientation regulator” at high current density, which significantly suppresses side reactions and dendrite growth. The in‐situ SEI affords the record‐breaking reversibility of Zn anode under practical conditions, Zn//Zn symmetric cells can stably cycle for over 1300 h and 400 h at current densities of 50 mA cm−2 and 100 mA cm−2, respectively, showcasing an exceptional cumulative capacity of 67.5 Ah cm−2. Furthermore, the practicality of this in‐situ SEI is verified in Zn//PANI pouch cells with high mass loading of 25.48 mg cm−2. This work provides a universal strategy to design advanced SEI for practical Zn‐ion batteries.