Tandem Interphase Design Achieves Two-Year Cycling of Aqueous Zinc Metal Batteries Under Extreme Conditions

The development of aqueous zinc metal batteries (AZMBs) is impeded by their limited lifespan, especially at extreme conditions (high current, low temperature etc.), primarily because the solid electrolyte interphase (SEI) on Zn anode cannot simultaneously balance the solvation/desolvation kinetics and deposition/stripping stability of Zn^{2 +}. The inherent incompatibility of the two properties stems from the inability of the SEI to simultaneously achieve hydrophilic-zincophobicity for rapid desolvation and hydrophobic-zincophilicity for stable deposition, which are inherently contradictory characteristics. Herein, we present a tandem structure SEI possessing outer-hydrophilicity/inner-zincophilicity (OHIZ) for Zn anode. Carboxylated carbon nanotubes (CCNT) and metallic tin (Sn) are screened as the outer/inner SEI (CCNT-Sn/Zn) via systematic screening framework. This tandem-structured SEI achieves a balance between the desolvation kinetics and deposition stability of Zn^{2 +} even at extreme current (100 mA cm^{- 2}) and temperature (-30°C∼-86°C). Moreover, the inner Sn undergoes a spontaneous phase transformation from β to α-phase at low temperature, leading to boosted ion transport kinetics. Correspondingly, the CCNT-Sn/Zn symmetric cells achieve remarkable stability more than two years at -30°C. The 1.3 Ah CCNT-Sn/Zn||LiMn₂O₄ pouch cells exhibit 94% capacity retention after 100 cycles. Our strategy provides valuable insight into the advancement of AZMBs.